United States Department of Agriculture

Proceedings of the Fifth Interagency Conference on Research in the Watersheds

Headwaters to Estuaries: Advances in 

Watershed Science and Management

March 2-5, 2015, North Charleston, South Carolina

Forest Service

Research & Development 

Southern Research Station

e-General Technical Report SRS-211
Cover art prepared by James R. Douglas of the U.S. Geological Survey, 

South Atlantic Water Science Center.

www.srs.fs.usda.gov 

January 2016

Southern Research Station

200 W.T. Weaver Blvd.

Asheville, NC 28804

Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, 

or otherwise does not necessarily constitute or imply endorsement, recommendation, or favoring by the United States 

Government. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the 

United States Government, and shall not be used for any endorsement purposes.

Papers published in these proceedings were submitted by authors in electronic media. Some editing was done to ensure 

a consistent format. Authors are responsible for content and accuracy of their individual papers and the quality of 

illustrative materials.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds

Headwaters to Estuaries: Advances in 

Watershed Science and Management

March 2-5, 2015, North Charleston, South Carolina

Edited by Christina E. Stringer, Ken W. Krauss, and James S. Latimer

CUAHSI

Sponsored by:
iv Headwaters to Estuaries: Advances in Watershed Science and Management

The Fifth Interagency Conference on Research in the 

Watersheds (ICRW) was held in North Charleston, 

South Carolina, March 2-5, 2015. The conference theme 

was selected to recognize the focus of many natural 

resource agencies and universities in understanding 

how ecosystems are connected from interior upland 

habitats to the estuaries, as land use in the upper portion 

of watersheds often affect hydrological, ecological, and 

sociological processes downstream. This theme builds 

on past ICRW programs held in Arizona, North Carolina, 

Colorado, and Alaska, by delivering a strong southeastern 

Coastal Plain theme while maintaining a broad national 

focus that highlights ongoing interagency research and 

management initiatives.

Human- and climate-mediated impacts to watersheds 

continue to mount nationally, from the accumulated 

effects of many small-scale actions (e.g., construction 

of new roads and neighborhoods) to large-scale 

development (e.g., port facilities) or climate anomalies 

affecting critically important watershed processes. 

While water resource issues are often discussed among 

western States, this issue came to the forefront in the 

Southeast during a wide-spread drought of 2005–2007. 

Residents of Tennessee, Florida, Alabama, and Georgia 

found themselves coping with water-use restrictions, 

affecting nearly everything from cropland irrigation and 

lake recreation to water quality and aquifer recharge. 

That issue, droughts in other regions, sea level rise, 

catastrophic wildfire, and severe storm events have 

lifted watershed science to national importance; 

studying individual habitats is necessary, but discerning 

connectivity among multiple individual habitats 

within a watershed is paramount to water and nutrient 

management.

The 5th ICRW was structured to focus on key issues 

faced by managers and scientists throughout the United 

States, with many of these issues having a strong coastal 

watershed focus. Thematic areas included managing 

forested wetlands and agricultural catchments, identifying 

research advances from experimental watersheds, 

tracking the fate of contaminants through landscapes, 

advancing restoration ecology of connected ecosystems, 

and understanding the role of climatic perturbations (e.g., 

drought, severe storms) on watersheds. In addition, the 

role that ecosystems play in water use and management 

was a focal point, including modeling and measuring 

evapotranspiration associated with land use change. 

The 5th ICRW provided 20 technical sessions and 

6 field trips for the 187 participants. The technical 

program contained talks, poster presentations, and 

plenary addresses. These proceedings serve as a written 

transaction for this meeting. The presenters were given 

the option to contribute an extended abstract or short 

paper to replace the short abstract that was conveyed in 

the program. Accordingly, the contributions are identified 

in three categories: (1) short abstracts, (2) extended 

abstracts, and (3) papers. The papers contained herein 

have undergone the requisite review process required by 

the authors’ institution and technical editing to provide 

a consistent format. My hope is that this proceeding will 

provide a timely conveyance of the excellent work that 

was presented at the conference and serve as a useful 

reference for all. 

The presentation of this excellent body of work could 

not have been possible without the commitment and hard 

work of the Program Committee, the excellent facilities 

provided at Trident Technical College, and the support 

provided by the USDA Forest Service, U.S. Geological 

Survey, U.S. Environmental Protection Agency, USDA 

Agricultural Research Service, North Carolina Water 

Resource Research Institute, and the North Carolina and 

South Carolina Sea Grant programs. The program for the 

5th ICRW is available at: http://www.hydrologicscience.

org/icrw5/.

With great appreciation for all those who participated in the 5th ICRW.

Carl C. Trettin, Conference Chair

USDA Forest Service

Preface
Proceedings of the Fifth Interagency Conference on Research in the Watersheds v

Supporting Agencies

USDA Forest Service

US Geological Survey

US Environmental Protection Agency

USDA Agricultural Research Service

North Carolina Water Resource Research Institute 

North Carolina and South Carolina Sea Grant Programs

Consortium of Universities for the Advancement of 

Hydrologic Science, Inc.

Conference Chair 

Carl Trettin, USDA Forest Service 

Steering Committee 

Scott Davis, Bureau of Land Management 

Rick Hooper, Consortium of Universities for the 

Advancement of Hydrologic Science, Inc. 

Chuck Lane, US Environmental Protection 

Agency- 6th ICRW Conference Chair 

Susan Moran, Agricultural Research Service, USDA

Rick Webb, US Geological Survey 

Technical Program 

Devendra Amatya, USDA Forest Service - Co-Chair 

Mary Culver, National Oceanic & Atmospheric 

Administration - Co-Chair 

Andy Dolloff, US Fish & Wildlife Service 

Natalie Griffiths, Oak Ridge National Laboratory, 

US Department of Energy 

Anand Jayakaran, Clemson University 

Bob McKane, US Environmental Protection Agency 

Denise Sanger, SC Department of Natural Resources 

Hayden Smith, College of Charleston 

Facility & Events 

Randy Fowler, USDA Forest Service, Chair 

Field Tours 

Paul Conrads, US Geological Survey - Chair 

Timothy Callahan, College of Charleston 

Heidi Hadley, Bureau of Land Management 

Raye Nilius, US Fish & Wildlife Service 

Proceedings Editors 

Christina Stringer, USDA Forest Service - Chair 

Ken Krauss, US Geological Survey 

Jim Latimer, US Environmental Protection Agency 

Communications 

Barbara Doll, NC Sea Grant - Chair 

Rick Devoe, SC Sea Grant 

Bill Kepner, US Environmental Protection Agency 

Rick Webb, US Geological Survey

Plenary Speakers

Jimmy Reaves, USDA Forest Service

Christopher Impellitteri, US Environmental Protection 

Agency

Jerad Bales, US Geological Survey

Irena Creed, University of Western Ontario

Laurie Alexander, US Environmental Protection Agency

Joe Gellici, South Carolina Department of Natural 

Resources

Mark Walbridge, USDA Agricultural Research Service

Lawrence Band, University of North Carolina

Session Moderators

Robert Doudrick, Bill Kepner, Carl Trettin—

Plenary Sessions

Ron McCormick—Managing Forested Wetlands in 

Coastal Watersheds

Devendra Amatya—Multicollaborative Research on 

Turkey Creek Watershed and Beyond

David Bosch, Devendra Amatya—New Insights into 

Studies on Long-term Experimental Watersheds

Paul Bradley—Mercury Fater, Transport, and 

Bioaccumulation in Wetland Influenced Ecosystems

Natalie Griffiths, Jim Latimer—Water Quality

Anand Jayakaran—Watershed Responses to Management 

and Restoration

Christina Stringer—Watershed Assessment: Tools 

and Data

Chuck Lane—Watershed Assessments at Multiple Scales

Hayden Smith—Environmental History of Lowcountry 

Rice Culture

Paul Conrads—Coastal Drought

Acknowledgments
vi Headwaters to Estuaries: Advances in Watershed Science and Management

Susan Moran—Assessments for Watershed Management

Mary Culver—Monitoring and Management

Barbara Doll—Linking Terrestrial and Marine 

Ecosystems

Rick Webb—Hydrology and Water Quality Monitoring

Brooke Czwartacki—Tidal Freshwater Rivers and Creeks

Andy Doloff—Interdisciplinary Research in the 

Watersheds

Devendra Amatya—Advances in Evapotranspiration and 

Modeling on Multiple Land Uses

Field Tour Facilitators

Cape Romain National Wildlife Refuge: Exploring Bulls 

Island—Chris Crolley, Coastal Expeditions

A Tour of the Santee Experimental Forest Research 

Watersheds, Huger, SC and the Tidal Freshwater 

Forested Watershed along Quenby Creek—Devendra 

Amatya and Andy Harrison, USDA Forest Service

Exploring the ACE Basin—John Lefler, South Carolina 

Department of Natural Resources

Tidal Marsh Reconnection and Restoration—Kim Counts 

Morganello, Clemson Extension; Lisa Vandiver, 

NOAA; Anand Jayakaran, Clemson 

Research and Coastal Zone Management Issues in 

the Southeastern United States: Considerations at 

the Interface of the Terrestrial Watersheds and the 

Ocean—Mike Fulton, NOAA 

Support Staff

Jessica Annadale, Consortium of Universities for the 

Advancement of Hydrologic Science, Inc.

Artheera Bayles, USDA Forest Service

Emily Clark, Consortium of Universities for the 

Advancement of Hydrologic Science, Inc.

Kathy Flowers, USDA Forest Service

Juanita Lockwood, USDA Forest Service

Chrissie Shepard, NC Sea Grant

Cathy Smith, NC Sea Grant

College of Charleston Student Assistants

Sean Bath

Austin Morrison

Mikala Randich

Andrea Sassard

Lauren Senn

Kimberly Sitta

Conference Venue

Trident Technical College Conference Center, North 

Charleston, SC

Proceedings Layout and Design

Virginia Ruark, USDA Forest Service

Maureen Stuart, USDA Forest Service

The organizers would like to thank all of the additional individuals not named here, including the 

conference participants and presenters, for helping to make the 5th ICRW such a success.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds vii

Contents

Preface...............................................................................................................................................................iv

Acknowledgments.............................................................................................................................................v

Plenary Session ............................................................................................................................................... 1

STRENGTHENING THE SCIENTIFIC FOUNDATION FOR THE CLEAN WATER ACT THROUGH 

FEDERAL PARTNERSHIP AND TRANSDISCIPLINARY COLLABORATION ................................................................ 1

Laurie C. Alexander, William G. Kepner, and David C. Goodrich

Managing Forested Wetlands in Coastal Watersheds ................................................................................... 5

OVERVIEW OF FOREST CONDITIONS IN COASTAL COUNTIES .............................................................................. 6

Eunice A. Padley, Sonja N. Oswalt

REGULATORY OVERVIEW .................................................................................................................................... 7

Robert Huff

LOSS OF FORESTED WETLANDS - QUESTIONS, ANSWERS, AND MORE QUESTIONS ........................................... 8

Susan-Marie Stedman

EMERGING ISSUES WITH SILVICULTURE PRACTICES IN WETLANDS ................................................................... 9

Mike Wylie

EFFECT OF MINOR DRAINAGE ON HYDROLOGY OF FORESTED WETLANDS ...................................................... 10

Wayne Skaggs, George Chescheir

SOUTH CAROLINA’S BEST MANAGEMENT PRACTICES FOR FORESTY FOR MINOR DRAINAGE...........................11

Tonya Smith, Herb Nicholson

Multicollabortive Research on Turkey Creek Watershed and Beyond: 

10-Year Accomplishments and New Directions .......................................................................................... 13

COASTAL PLAIN SOILS AND GEOMORPHOLOGY: A KEY TO UNDERSTANDING FOREST HYDROLOGY ............... 14

Thomas M. Williams and Devendra M. Amatya 

TEN YEARS OF REAL-TIME STREAMFLOW GAGING OF TURKEY CREEK – WHERE WE HAVE 

BEEN AND WHERE WE ARE GOING .................................................................................................................... 22

Paul Conrads, Devendra Amatya

SYNTHESIS OF 10-YEARS OF HYDROLOGIC STUDIES ON TURKEY CREEK WATERSHED 

AND NEW INITIATIVES ........................................................................................................................................ 23

Devendra Amatya, Carl Trettin

DECIPHERING STORM-EVENT RUNOFF BEHAVIOR IN A COASTAL PLAIN WATERSHED 

USING CHEMICAL AND PHYSICAL HYDROGRAPH SEPARATION TECHNIQUES ................................................... 34

Timothy Callahan, Austin E. Morrison

DEFINING ECOHYDROLOGICAL FUNCTION TO SUPPORT LOW IMPACT 

DEVELOPMENT IN COASTAL SOUTH CAROLINA ................................................................................................ 35

Daniel Hitchcock, A.D. Jayakaran, T. H. Epps, J. A. Palazzolo, T. M. Williams, D. M. Amatya

ENHANCING HYDROLOGIC MAPPING USING LIDAR AND HIGH RESOLUTION AERIAL 

PHOTOS ON THE FRANCIS MARION NATIONAL FOREST IN COASTAL SOUTH CAROLINA ................................... 36

Andy Maceyka and William F. Hansen
viii Headwaters to Estuaries: Advances in Watershed Science and Management

FRANCIS MARION NATIONAL FOREST FOREST PLAN REVISION-ECOSYSTEMS & 

RESTORATION NEEDS ....................................................................................................................................... 40

Mark Danaher

New Insights into Studies on Long-term Experimental Watersheds to Address 

Contemporary Emerging Issues (PART 1) .................................................................................................... 41

THE LONG TERM AGROECOSYSTEM RESEARCH NETWORK – SHARED RESEARCH STRATEGY ........................ 42

Jean L. Steiner, Timothy Strickland, Peter J.A. Kleinman, Kris Havstad, Thomas B. Moorman, 

M. Susan Moran, Phil Heilman, Ray B. Bryant, David Huggins, and Greg McCarty

PERSPECTIVES ON THE DEVELOPING COMMON EXPERIMENT ACROSS THE 18 SITES 

WITHIN THE LONG TERM AGROECOSYSTEM RESEARCH NETWORK ................................................................. 52

Kris Havstad

STORYTELLING TO SUPPORT WATERSHED RESEARCH ON EMERGING ISSUES ................................................ 53

Philip Heilman

THE USDA-ARS EXPERIMENTAL WATERSHED NETWORK – EVOLUTION, LESSONS 

LEARNED, AND MOVING FORWARD ................................................................................................................... 54

David Goodrich, Phil Heilman, Susan Moran, Jurgen Garbrecht, Danny Marks, David Bosch, 

Jean Steiner, John Sadler, Matt Romkens, Daren Harmel, Peter Kleinman, Stacey Gunter, Mark Walbridge

CENTRAL MISSISSIPPI RIVER BASIN LTAR SITE OVERVIEW ............................................................................... 61

Edward J. Sadler, Claire Baffaut, Kenneth A. Sudduth, Robert N. Lerch, Newell R. Kitchen, 

Earl D. Vories, Kristen S. Veum, and Matt A. Yost

THE SOUTHERN PLAINS LTAR WATERSHED RESEARCH PROGRAM ................................................................... 68

Patrick Starks, Jean L. Steiner

Mercury Fate, Transport, and Bioaccumulation in Wetland Influenced Ecosystems: 

Field Studies and Modeling ........................................................................................................................... 69

IMPACT OF BASIN SCALE AND TIME-WEIGHTED MERCURY METRICS ON 

INTRA-/INTER-BASIN MERCURY COMPARISONS ............................................................................................... 70

Paul Bradley, Mark E. Brigham

WATERSHED CYCLING OF MERCURY AND CONTROLS ON METHYLMERCURY PRODUCTION IN 

NORTHERN MINNESOTA LANDSCAPES ............................................................................................................. 71

Randy Kolka, Carl Mitchell, Ed Nater

SENSITIVITY OF STREAM METHYL HG CONCENTRATIONS TO ENVIRONMENTAL CHANGE IN THE 

ADIRONDACK MOUNTAINS OF NEW YORK, USA ................................................................................................ 72

Doug Burns, Karen Riva Murray, Elizabeth A. Nystrom, David M. Wolock, Geofrey Millard, Charles T. Driscoll

OPTIMIZING FISH AND STREAM-WATER MERCURY METRICS FOR CALCULATION 

OF FISH BIOACCUMULATION FACTORS ............................................................................................................. 73

Paul Bradley, Karen Riva Murray, Barbara C. Scudder Eikenberry, Christopher D. Knightes, 

Celeste A. Journey, Mark A. Brigham

SIMULATING MERCURY AND METHYL MERCURY STREAM CONCENTRATIONS AT MULTIPLE 

SCALES IN A WETLAND INFLUENCED COASTAL PLAIN WATERSHED (McTIER CREEK, SC, USA) ........................ 74

Chris Knightes, G.M. Davis, H.E. Golden, P.A. Conrads, P.M. Bradley, C.A. Journey

SCALING UP WATERSHED MODEL PARAMETERS—

FLOW AND LOAD SIMULATIONS OF THE EDISTO RIVER BASIN .......................................................................... 75

Toby Feaster, Stephen Benedict, Jimmy Clark, Paul Bradley, Paul Conrads
Proceedings of the Fifth Interagency Conference on Research in the Watersheds ix

EVALUATION OF MERCURY LOADS FROM CLIMATE CHANGE PROJECTIONS .................................................... 76

Paul Conrads, Paul M. Bradley, Stephen T. Benedict, Toby D. Feaster

CLIMATE CHANGE AND WATERSHED MERCURY EXPORT IN A COASTAL PLAIN WATERSHED ............................ 77

Heather Golden, Christopher D. Knightes, Paul A. Conrads, Toby D. Feaster, Gary M. Davis, 

Stephen T. Benedict, Paul M. Bradley

Water Quality (PART 1)................................................................................................................................... 79

THE USE OF ACOUSTIC DOPPLER METERS TO ESTIMATE SEDIMENT AND NUTRIENT 

CONCENTRATIONS IN FRESHWATER INFLOWS TO TEXAS COASTAL ECOSYSTEMS .......................................... 80

Zulimar Lucena, Michael Lee

FUSING LONG-TERM, HISTORICAL, AND HIGH-RESOLUTION DATA TO INFORM 

ESTIMATES OF WATERSHED-SCALE NITROGEN RETENTION ............................................................................. 81

Jonathan Duncan, Lawrence Band

COMPARING NUTRIENT EXPORT FROM FIRST, SECOND, AND THIRD ORDER 

WATERSHEDS IN THE SOUTH CAROLINA ATLANTIC COASTAL PLAIN ................................................................. 82

Augustine Muwamba, Devendra M. Amatya, Carl C. Trettin, and James B. Glover

QUANTIFYING IN-STREAM NITRATE REACTION RATES USING CONTINUOUSLY-COLLECTED 

WATER QUALITY DATA....................................................................................................................................... 89

Matthew Miller, Anthony Tesoriero, Paul Capel

A WATERSHED-SCALE CHARACTERIZATION OF DISSOLVED ORGANIC CARBON 

AND NUTRIENTS ON THE SOUTH CAROLINA COASTAL PLAIN ........................................................................... 90

Daniel Tufford, Setsen Altan-Ochir

Water Responses to Management and Restoration .................................................................................... 91

EVALUATING HYDROLOGICAL RESPONSE OF FUTURE LAND COVER CHANGE SCENARIOS IN 

THE SAN PEDRO RIVER (U.S./MEXICO) WITH THE AUTOMATED GEOSPATIAL WATERSHED 

ASSESSMENT (AGWA) TOOL .............................................................................................................................. 92

William G. Kepner, I. Shea Burns, David. C. Goodrich, D. Phillip Guertin, Gabriel S. Sidman, 

Lainie R. Levick, Wilson W.S. Yee, Melissa M.A. Scianni, Clifton .S. Meek, Jared B. Vollmer

ECOHYDROLOGY OF A FLOODPLAIN FOREST: RELATIONSHIPS BETWEEN VEGETATION 

AND GROUNDWATER RESOURCES AT CONGAREE NATIONAL PARK, SOUTH CAROLINA USA .......................... 102

Timothy Callahan, Lauren Senn

RELATIONSHIPS BETWEEN WILDLAND FIRES AND WATERSHED HYDROLOGY 

ACROSS THE CONTIGUOUS U.S. ..................................................................................................................... 103

Dennis W. Hallema, Ge Sun, Peter V. Caldwell, Steven P. Norman, Erika C. Cohen, 

Yongqiang Liu, Steven G. McNulty

RIPARIAN AREA HARVESTING IMPACTS ON VEGETATION COMPOSITION AND DIVERSITY ............................... 104

Katherine Elliot, James M. Vose

ADVANCING STREAM RESTORATION DESIGN: A SCIENCE-BASED APPROACH 

USING DATA AND METHODOLOGIES FROM THE AGENCIES ............................................................................. 105

Jessica Palazzolo, Joshua Robinson, Philip Ellis

Watershed Assessment- Tools and Data .................................................................................................... 107

MANAGING THE SPACE-TIME-LOAD CONTINUM IN TMDL PLANNING: A CASE STUDY FOR UNDERSTANDING 

GROUNDWATER LOADS THROUGH ADVANCED MAPPING TECHNIQUES ......................................................... 108

Phillip Harte, Marcel Belaval, Andrea Traviglia
x Headwaters to Estuaries: Advances in Watershed Science and Management

THE ROLE OF WATERSHED CHARACTERISTICS IN ESTUARINE CONDITION: 

AN EMPIRICAL APPROACH .............................................................................................................................. 109

James Latimer, Melissa Hughes, Michael Charpentier, Christine Tilburg

WETLAND EXTENT AND PLANT COMMUNITY COMPOSITION VULNERABILITY 

TO CLIMATE CHANGE.......................................................................................................................................110

Michael Nassry, Denice H. Wardrop, Anna T. Hamilton, Christopher J. Duffy, Jordan M. West

LAND COVER CHANGE IN COASTAL WATERSHEDS 1996 TO 2010 .....................................................................111

Nate Herold

MAPPING VARIABLE WIDTH RIPARIAN BUFFERS ..............................................................................................112

Sinan Abood

Watershed Assessments at Multiple Scales ...............................................................................................113

PAIRED FORESTED WATERSHED EXPERIMENTS IN THE PIEDMONT OF NORTH CAROLINA ..............................114

Johnny Boggs, Ge Sun, Steven McNulty

VERIFICATION OF HYDROLOGIC LANDSCAPE DERIVED BASIN-SCALE CLASSIFICATIONS 

IN THE PACIFIC NORTHWEST ...........................................................................................................................115

Keith Sawicz

WATERSHED AND LONGITUDINAL MONITORING EVENTS .................................................................................116

Harold Harbert, Steven Blackburn

A VALIDATION STUDY OF A RAPID FIELD-BASED RATING SYSTEM FOR DISCRIMINATING 

AMONG FLOW PERMANENCE CLASSES OF HEADWATER STREAMS IN SOUTH CAROLINA ...............................117

William Wenerick, Ken M. Fritz, Mitchell S. Kostich

QUANTIFYING VARIABILITY: PATTERNS IN WATER QUALITY AND BIOTA FROM 

A LONG-TERM, MULTI-STREAM DATASET .........................................................................................................118

Camille Flinders, Douglas McLaughlin

WATERSHEDS, ECOREGIONS AND HYDROLOGIC UNITS: THE APPROPRIATE USE OF

EACH FOR RESEARCH AND ENVIRONMENTAL MANAGEMENT DECISIONS .......................................................119

James Glover, James Omernik, Robert Hughes, Glenn Griffith, Marc Weber

Environmental History of Lowcountry Rice Culture: A Current Study 

of Interdisciplinary Investigations .............................................................................................................. 121

ENVIRONMENTAL RELATIONS BETWEEN INLAND RICE CULTURE AND THE COOPER 

AND WANDO RIVER WATERSHEDS, SOUTH CAROLINA .................................................................................... 122

Hayden R. Smith

CLAY IS EVERYTHING: ARCHAEOLOGICAL ANALYSES OF COLONIAL PERIOD 

INLAND SWAMP RICE EMBANKMENTS ............................................................................................................ 129

Andrew Agha

ADVANCED GEOSPATIAL TECHNIQUES AND ARCHAEOLOGICAL METHODS TO 

INVESTIGATE HISTORICAL RICE CULTIVATION AT WORMSLOE HISTORIC SITE ................................................ 132

Alessandro Pasqua

Coastal Drought............................................................................................................................................ 133

DROUGHT AND COASTAL ECOSYSTEMS: AN ASSESSMENT 

OF DECISION MAKER NEEDS FOR INFORMATION ............................................................................................ 134

Kirsten Lackstrom, Amanda Brennan, Kirstin Dow
Proceedings of the Fifth Interagency Conference on Research in the Watersheds xi

DEVELOPMENT OF A COASTAL DROUGHT INDEX USING SALINITY DATA��������������������������������������������������������� 135

Paul Conrads, Lisa Darby

A WATERSHED-SCALE CHARACTERIZATION OF DISSOLVED ORGANIC CARBON 

AND NUTRIENTS ON THE SOUTH CAROLINA COASTAL PLAIN ������������������������������������������������������������������������� 136

Daniel L. Tufford, Setsen Altan-Ochir, Warren Hankinson

THE EXTENT OF TIDAL INFLUENCE IN THE WACCAMAW RIVER, SOUTH CAROLINA����������������������������������������� 137

Benjamin Thepaut, John Shelton, Susan Libes, Paul Conrads, Robert Sheehan

New Insights into Studies on Long-term Experimental Watersheds to 

Address Contemporary Emerging Issues (PART 2) ����������������������������������������������������������������������������������� 139

HYDROLOGIC CHANGE IN A COAST REDWOOD FOREST, CASPAR CREEK 

EXPERIMENTAL WATERSHEDS: IMPLICATIONS FOR SALMONID SURVIVAL ������������������������������������������������������ 140

Elizabeth Keppeler

IMPACT OF SOIL MOISTURE DEFICIT ON ECOSYSTEM FUNCTION ACROSS THE UNITED STATES�������������������� 148

Susan Moran, Morgan Ross, Mallory Burns

TESTING RESILIENCY OF HYDROLOGIC DYNAMICS OF A PAIRED FORESTED WATERSHED 

AFTER A HURRICANE IN ATLANTIC COASTAL PLAIN USING LONG-TERM DATA������������������������������������������������ 149

Devendra Amatya, Herbert Ssegane, Charles Andy Harrison, Carl Trettin

HYDROLOGICAL EFFECTS OF TROPICAL LAND USE MANAGEMENT INCENTIVES: 

PANAMA CANAL WATERSHED ������������������������������������������������������������������������������������������������������������������������� 150

Fred Ogden, Jefferson S. Hall, Holly Barnard, Robert F. Stallard, Eli Fenichel, Vic Adamowicz, Brent Ewers, 

Ed Kempema, Julian Zhu

IDENTIFICATION OF TEMPORAL PATTERNS OF LONG-TERM HYDROLOGICAL SIGNALS 

IN LOWER MISSISSIPPI RIVER BASIN USING WAVELET ANALYSIS�������������������������������������������������������������������� 151

Ying Ouyang

Assessments for Watershed Management ������������������������������������������������������������������������������������������������ 153

INTEGRATING TIDAL AND NONTIDAL ECOLOGICAL ASSESSMENTS����������������������������������������������������������������� 154

Mark Southerland and Roberto Llansó

DEVELOPMENT OF AN INTEGRATED ECOSYSTEM MODEL TO DETERMINE EFFECTIVENESS 

OF POTENTIAL WATERSHED MANAGEMENT PROJECTS ON IMPROVING OLD TAMPA BAY ������������������������������ 156

Edward T. Sherwood, Holly Greening, Lizanne Garcia, Kris Kaufman, Tony Janicki, Ray Pribble, 

Brett Cunningham, Steve Peene, Jim Fitzpatrick, Kellie Dixon, and Mike Wessel

WATERSHED PLANNING, IMPLEMENTATION AND ASSESSMENT: 

THE MAY RIVER WATERSHED ACTION PLAN CASE STUDY������������������������������������������������������������������������������� 164

Kimberly W. Jones, Christopher L. Ellis, Jeremy S. Ritchie

THE 2014 ASSESSMENT OF STREAM QUALITY IN THE PIEDMONT AND SOUTHERN 

APPALACHIAN MOUNTAIN REGION OF SOUTHEASTERN UNITED STATES �������������������������������������������������������� 171

Celeste Journey, Paul M. Bradley, Peter Van Metre

CEAP WATERSHED ASSESSMENTS: ACCOMPLISHMENTS 

AND OPPORTUNITIES FOR NEW ADVANCES���������������������������������������������������������������������������������������������������� 172

Lisa Duriancik, Mark Walbridge, Deanna Osmond, Roberta Parry

USDA’S NATIONAL INSTITUTE OF FOOD AND AGRICULTURE (NIFA): ENGAGING KNOWLEDGE 

AND TECHNOLOGY, INCENTIVES AND POLICIES TO PROMOTE APPROPRIATE DECISION 

MAKING IN THE MANAGEMENT OF WATER AND WATERSHEDS ����������������������������������������������������������������������� 173

James Dobrowolski
xii Headwaters to Estuaries: Advances in Watershed Science and Management

Water Quality (PART 2)................................................................................................................................. 175

SOIL AND STREAM CHEMISTRY RELATIONSHIPS IN HIGH ELEVATION WATERS ............................................... 176

Jennifer Knoepp, Katherine J. Elliott, William A. Jackson, James M. Vose, Chelcy Ford Miniat, Stanley J. Zarnoch

SOIL AND SALINITY MOBILIZATION AND TRANSPORT 

IN THE COLORADO RIVER BASIN ..................................................................................................................... 177

Cole Green Rossi, Mark A. Weltz, Kossi Nouwakpo, Ken McGwire

NUTRIENT AND SALT MASS BALANCE ON THE LOWER ARKANSAS RIVER AND A CONTRIBUTING 

TRIBUTARY IN AN IRRIGATED AGRICULTURAL SETTING .................................................................................. 178

Alexander Huizenga, Ryan T. Bailey, Timothy K. Gates

EVALUATING THE EFFECTS OF WOODY BIOMASS PRODUCTION FOR BIOENERGY ON 

WATER QUALITY AND HYDROLOGY IN THE SOUTHEASTERN UNITED STATES ................................................. 179

Natalie Griffiths, C. Rhett Jackson, Menberu Bitew, Enhao Du, Kellie Vaché, 

Jeffrey J. McDonnell, Julian Klaus, and Benjamin M. Rau

UNDERWATER AERATION AND ARTIFICIAL FLOATING WETLANDS TO TREAT WATER 

QUALITY NUTRIENT ISSUES IN PONDS ............................................................................................................ 180

Mike Haberland, Craig McGee

Monitoring and Management ...................................................................................................................... 181

REGIONAL EFFECTS OF AGRICULTURAL CONSERVATION PRACTICES ON NUTRIENT TRANSPORT ................. 182

Anna Maria Garcia, Richard B. Alexander, Jeffrey G. Arnold, Lee Norfleet, 

Mike White, Dale M. Robertson, Gregory Schwarz

ASSESSMENT OF FORESTRY BEST MANAGEMENT PRACTICES, I: STREAM WATER 

CHEMISTRY NATURAL VARIABILITY AND FERTILIZATION INFLUENCES ............................................................ 183

Erik Schilling, Daniel McLaughlin, Matt Cohen, Larry Korhnak, Paul Decker, Camille Flinders 

ASSESSMENT OF FORESTRY BEST MANAGEMENT PRACTICES, II: PATTERNS IN STREAM 

BIOLOGICAL ENDPOINTS IN TERMS OF NATURAL VARIABILITY AND FERTILIZATION ....................................... 184

Camille Flinders, Daniel L McLaughlin, Larry Korhnak, William J Arthurs, Joan Ikoma, 

Matthew J Cohen, Erik B Schilling

CONTINUOUS WATER-QUALITY MONITORING TO IMPROVE LAKE MANAGEMENT AT 

LAKE MATTAMUSKEET NATIONAL WILDLIFE REFUGE ...................................................................................... 185

Michelle Moorman, Tom Augspurger 

MANAGING WATERSHEDS TO CHANGE WATER QUALITY: LESSONS LEARNED FROM 

THE NIFA-CEAP WATERSHED STUDIES ............................................................................................................ 186

Deanna Osmond, M. Arabi, D. Hoag, G. Jennings, D. Line, A. Luloff, M. McFarland, D. Meals, A. Sharpley

Linking Terrestrial and Marine Ecosystems ............................................................................................... 187

THE PHYSICAL AND GEOCHEMICAL INTERACTION BETWEEN A TIDALLY-DOMINATED ESTUARY 

SYSTEM (WASSAW SOUND, GA) AND A RIVER-DOMINATED ESTUARY (SAVANNAH RIVER, GA) 

THROUGH SALINITY AND INORGANIC CARBON ............................................................................................... 188

Mike Scaboo, Christopher Hintz

WATER SOURCES IN MANGROVES IN FOUR HYDROGEOMORPHIC SETTINGS IN FLORIDA AND MEXICO ........ 189

Christina Stringer, Mark Rains

DESIGNING A MANGROVE RESEARCH AND DEMONSTRATION FOREST IN THE RUFIJI DELTA, TANZANIA ........ 190

Mwita M. Mangora, Mwanahija S. Shalli, Immaculate S. Semesi, 

Marco A. Njana, Emmanuel J. Mwainunu, Jared E. Otieno, Elias Ntibasubile, Herry C. Mallya, 

Kusaga Mukama, Matiko Wambura, Nurdin A. Chamuya, Carl C. Trettin, Christina E. Stringer
Proceedings of the Fifth Interagency Conference on Research in the Watersheds xiii

WATERSHED MANAGEMENT TO SUPPORT CORAL REEF RECOVERY AND RESILIENCY ................................... 193

Lisa Vandiver, Tom Moore, Sean Griffin, Michael Nemeth, Rob Ferguson

WATERSHED PROCESSES FROM RIDGE TO REEF: CONSEQUENCES OF FERAL UNGULATES 

FOR CORAL REEF AND EFFECTS OF WATERSHED MANAGEMENT ................................................................... 194

Gordon Tribble, Jonathan Stock, Jim Jacobi

Hydrology and Water Quality Monitoring ................................................................................................... 195

LINKING STATISTICALLY- AND PHYSICALLY-BASED MODELS FOR IMPROVED STREAMFLOW 

SIMULATION IN GAGED AND UNGAGED WATERSHEDS .................................................................................... 196

Jacob LaFontaine, Lauren Hay, Stacey Archfield, William Farmer, Julie Kiang

BLIZZARDS TO HURRICANES: COMPUTER MODELING OF HYDROLOGY, WEATHERING, 

AND ISOTOPIC FRACTIONATION ACROSS HYDROCLIMATIC REGIONS ............................................................. 197

Richard MT Webb, David L Parkhurst

A WATERSHED-BASED SPATIALLY-EXPLICIT DEMONSTRATION OF AN INTEGRATED 

ENVIRONMENTAL MODELING FRAMEWORK FOR ECOSYSTEM SERVICES IN THE 

COAL RIVER BASIN (WV, USA) .......................................................................................................................... 198

John M. Johnston, Mahlon C. Barber, Kurt Wolfe, Mike Galvin, Mike Cyterski, Rajbir Parmar, Luis Suárez

WATERSHED MODELING AND DEVELOPMENT OF ECOLOGICAL FLOWS IN THE APALACHICOLACHATTAHOOCHEE-FLINT RIVER BASIN, ALABAMA, FLORIDA, AND GEORGIA................................................... 199

William Hughes, Mary Freeman, Elliott Jones, John Jones, Jacob Lafontaine, Jaime Painter, 

Lynn Torak, Steve Walsh

INTERANNUAL VARIABILITY IN THE EXTENT OF WETLAND-STREAM CONNECTIVITY WITHIN THE 

PRAIRIE POTHOLE REGION ............................................................................................................................. 200

Melanie Vanderhoof, Laurie Alexander 

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions ................. 201

UNDERSTANDING THE LINKAGES BETWEEN A TIDAL FRESHWATER FORESTED WETLAND 

AND AN ADJOINING BOTTOMLAND HARDWOOD FOREST ............................................................................... 202

Brooke Czwartacki, Carl C. Trettin, Timothy J. Callahan

BIOGEOCHEMICAL AND SURFACE ELEVATION CONTROLS OVER TIDALLY INFLUENCED 

FRESHWATER FORESTED WETLANDS AS THEY TRANSITION TO MARSH ........................................................ 203

William Conner, Ken W. Krauss, Gregory B. Noe, Jamie A. Duberstein, Nicole Cormier, Camille L. Stagg

TRACKING SALINITY INTRUSIONS IN A COASTAL FORESTED FRESHWATER WETLAND SYSTEM ..................... 204

Anand D. Jayakaran, Thomas M. Williams, and William H. Conner

LINKING TIDAL HYDROLOGY TO CARBON CYCLING IN BOTTOMLAND HARDWOOD FORESTS ........................ 207

Carl C. Trettin, Brooke J. Czwartacki, Craig J. Allan, Devendra M. Amatya

DETERMINING VOLUME SENSITIVE WATERS IN BEAUFORT COUNTY, SC TIDAL CREEKS ................................. 214

Andrew Tweel, Denise Sanger, Anne Blair, John Leffler 

STORMWATER RUNOFF IN WATERSHEDS: A SYSTEM FOR PREDICTING IMPACTS OF 

DEVELOPMENT AND CLIMATE CHANGE .......................................................................................................... 215

Ann Blair, Denise Sanger, Susan Lovelace
xiv Headwaters to Estuaries: Advances in Watershed Science and Management

Interdisciplinary Research in the Watersheds: A Forum for Team Players ............................................. 217

ENVIRONMENTAL SUSTAINABILITY OF INTERCROPPING SWITCHGRASS IN A LOBLOLLY PINE FOREST .......... 218

Andrew Dolloff, Craig Roghair, Colin Krause, John Moran, Allison Cochran, 

Mel Warren, Susie Adams, Wendell Haag 

ENVIRONMENTAL SUSTAINABILITY OF INTERCROPPING SWITCHGRASS IN A LOBLOLLY PINE FOREST .......... 219

George Chescheir, François Birgand, Mohamed Youssef, Jami Nettles, Devendra Amatya

PREDICTING FISH POPULATION DYNAMICS WITH SPATIALLY EXPLICIT, INDIVIDUAL-BASED MODELS: 

INTEGRATION OF ECOLOY, HYDROLOGY, GEOMORPHOLOGY AND MORE ....................................................... 220

Bret Harvey, Steve Railsback

MANAGEMENT OF RIPARIAN AND AQUATIC ECOSYSTEMS USING VARIABLE-WIDTH BUFFERS ....................... 221

Brian Pickard, Gordon H. Reeves, K. Norman Johnson

WILD SALMON RESPONSE TO NATURAL DISTURBANCE PROCESSES ............................................................. 222

Russell F. Thurow, John M. Buffington

AN ECOLOGICAL ASSESSMENT OF LAND USE IMPACTS IN SMALL WATERSHEDS

OF THE CHESAPEAKE BAY .............................................................................................................................. 223

Andrew Leight, John Jacobs, Lonnie Gonsalves, Gretchen Messick, Shawn McLaughlin, 

Jay Lewis, Julianna Brush, Eric Daniels, Matthew Rhodes, Lewis Collier, Robert Wood

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary 

Emerging Issues (PART 3) ............................................................................................................................ 225

INSIGHTS FROM LONG-TERM RESEARCH ON THE FERNOW EXPERIMENTAL FOREST .................................... 226

Mary Beth Adams

LONG-TERM HYDROLOGIC RESEARCH ON THE SAN DIMAS EXPERIMENTAL FOREST, 

SOUTHERN CALIFORNIA: LESSONS LEARNED AND FUTURE DIRECTIONS ....................................................... 227

Peter M. Wohlgemuth

WATER-LIMITING CONDITIONS BASED ON MONTHLY WATER BALANCES AND POTENTIAL 

EVAPOTRANSPIRATION AT PANOLA MOUNTAIN RESEARCH WATERSHED, GEORGIA, U.S.A. ............................ 233

Brent Aulenbach, Norman E. Peters, James Freer

CHANGES IN BASEFLOW CONDITIONS OVER A 42 YEAR OBSERVATION PERIOD FOR THE 

LITTLE RIVER EXPERIMENTAL WATERSHED IN SOUTH GEORGIA ..................................................................... 234

David D. Bosch, Randall G. Williams, Timothy C. Strickland, Jeff G. Arnold and Peter G. Allen

THIRTY-YEAR RESULTS FROM A PAIRED-CATCHMENT STUDY OF UPLAND FLOWPATH 

RESPONSES TO FOREST COVER CONVERSION IN NORTHERN MINNESOTA .................................................... 237

Stephen Sebestyen, Randy Kolka

LONG TERM RECORDS PROVIDE INSIGHTS ON THE RELATIVE INFLUENCE OF CLIMATE AND 

FOREST COMMUNITY STRUCTURE ON WATER YIELD IN THE SOUTHERN APPALACHIANS .............................. 238

Peter Caldwell, Chelcy Ford Miniat, Steven Brantley, Katherine Elliott, Stephanie Laseter, Wayne Swank

EVALUATING BIOLOGICAL AND PHYSICAL DRIVERS OF EVAPOTRANSPIRATION TRENDS AT 

NORTHEASTERN US WATERSHEDS ................................................................................................................. 239

John L. Campbell, Matthew A. Vadeboncoeur, Heidi Asbjornsen, Mark B. Green, Mary Beth Adams, 

and Elizabeth W. Boyer
Proceedings of the Fifth Interagency Conference on Research in the Watersheds xv

Advances in Evapotranspiration and Modeling on Multiple Land Uses .................................................. 243

UNDERSTANDING AND MANAGING THE WATER USE OF PLANTED FORESTS IN A 

CHANGING ENVIRONMENT .............................................................................................................................. 244

Jami Nettles

COMPARATIVE ANALYSES OF MEASURED EVAPOTRANSPIRATION FOR VARIOUS LAND SURFACES ................ 245

Suat Irmak

URBAN EVAPOTRANSPIRATION IN A HUMID ENVIRONMENT - ORLANDO, FLORIDA, USA ................................. 246

David M. Sumner, Cor M. J. Jacobs

OPERATIONAL ET REMOTE SENSING (RS) PROGRAM FOR IRRIGATION SCHEDULING 

AND MANAGEMENT: CHALLENGES AND OPPORTUNITIES ............................................................................... 247

Prasanna Gowda

ADVANCED IMAGE PROCESSING APPROACH FOR ET ESTIMATION WITH REMOTE 

SENSING DATA OF VARYING SPECTRAL, SPATIAL AND TEMPORAL RESOLUTIONS .......................................... 248

Sudhanshu Panda, Devendra Amatya, Young Kim, Ge Sun

ESTIMATING WATERSHED EVAPOTRANSPIRATION ACROSS THE UNITED STATES 

USING MULTIPLE METHODS ............................................................................................................................ 249

Ge Sun, Shanlei Sun, Jingfeng Xiao, Peter Caldwell, Devendra Amatya, Suat Irmak, 

Prasanna H. Gowda, Sudhanshu Panda, Steve McNulty, Yang Zhang

Poster Session .............................................................................................................................................. 251

LONG-TERM TRENDS IN CLIMATE AND HYDROLOGY IN AN AGRICULTURAL 

HEADWATER WATERSHED OF CENTRAL PENNSYLVANIA, USA ........................................................................ 252

Ray B. Bryant, Haiming Lu, Kyle R. Elkin, Anthony R. Buda, Amy S. Collick, Gordon J. Folmar, and Peter J. Kleinman 

THE WALNUT GULCH LTAR .............................................................................................................................. 261

Phillip Heilman, Susan Moran, Mark Nearing, Mary Nichols, Russ Scott, David Goodrich

LONG TERM AGROECOSYSTEM RESEARCH IN THE SOUTHERN PLAINS ........................................................ 262

Jean L. Steiner, Patrick J. Starks, Jurgen Garbrecht, Daniel Moriasi, Paul Bartholomew, Jim Neel, 

Kenneth E. Turner, and Brian Northup

GULF ATLANTIC COASTAL PLAIN LONG TERM AGROECOSYSTEM RESEARCH SITE, TIFTON, GA..................... 265

Timothy Strickland, David D. Bosch, Dinku M. Endale, Thomas L. Potter

REYNOLDS CREEK LONG-TERM AGRICULTURAL RESEARCH .......................................................................... 266

Mark Seyfried, Fred Pierson, Tony Svjecar, Kathleen Lohse

AN INTERACTIVE TOOL FOR PROCESSING SAP FLUX DATA FROM THERMAL DISSIPATION PROBES ............... 267

A. Christopher Oishi, Chelcy F. Miniat

THE CONEWAGO CREEK INITIATIVE: A MODEL FOR COMMUNITY WATERSHED ENGAGEMENT 

AND RESTORATION ......................................................................................................................................... 268

Matt Royer, Kristen Kyler, Jennifer Fetter

CONEWAGO STREAM TEAMS – INCLUDING YOUTH IN WATERSHED RESTORATION 

CREATES LOCAL WATERSHED CONNECTIONS, PROMPTS COMMUNITY SERVICE, 

AND INCREASES WATER LITERACY IN YOUTH ................................................................................................. 269

Jennifer Fetter, Sanford Smith, Matt Royer

CHANGES IN SEDIMENT YIELD AND STREAM MORPHOLOGY IN AN ACTIVELY MANAGED 

FORESTED WATERSHED DUE TO UPSTREAM DISTURBANCES ........................................................................ 270

Ilkim Cavus, Latif Kalin, Ferhat Kara
xvi Headwaters to Estuaries: Advances in Watershed Science and Management

REAL TIME MONITORING OF NITROGEN, CARBON, AND SUSPENDED SEDIMENT FLUX IN 

TWO SUBBASINS OF THE CHOPTANK RIVER WATERSHED ������������������������������������������������������������������������������ 271

Gregory McCarty, Megan Lang

ALBEMARLE SOUND DEMONSTRATION STUDY OF THE NATIONAL MONITORING 

NETWORK FOR U.S. COASTAL WATERS AND THEIR TRIBUTARIES������������������������������������������������������������������� 272

Michelle Moorman, Sharon Fitzgerald, Keith Loftin, and Elizabeth Fensin

PUBLICALLY ACCESSIBLE DECISION SUPPORT SYSTEM OF THE SPATIALLY REFERENCED 

REGRESSIONS ON WATERSHED ATTRIBUTES (SPARROW) MODEL AND MODEL 

ENHANCEMENTS IN SOUTH CAROLINA����������������������������������������������������������������������������������������������������������� 273

Celeste Journey, Anne B. Hoos, David E. Ladd, John W. Brakebill, Richard A. Smith

THE MID-ATLANTIC REGIONAL WETLAND CONSERVATION EFFECTS ASSESSMENT PROJECT ������������������������ 274

Megan Lang, Greg McCarty, Mark Walbridge, Patrick Hunt, Tom Ducey, Clinton Church, Jarrod Miller, 

Laurel Kluber, Ali Sadeghi, Martin Rabenhorst, Amir Sharifi, In-Young Yeo, Andrew Baldwin, Margaret Palmer, 

Tom Fisher, Dan Fenstermacher, Sanchul Lee, Owen McDonough, Metthea Yepsen, Liza McFarland, 

Anne Gustafson, Rebecca Fox, Chris Palardy, William Effland, Mari-Vaughn Johnson, Judy Denver, Scott Ator, 

Joseph Mitchell, Dennis Whigham

GUAM PAGO WATERSHED CONSERVATION ����������������������������������������������������������������������������������������������������� 276

Maria Lynn Cruz, Laura F. Biggs

HAS THE PROMISE OF DNA BARCODING BEEN ACHIEVED? 

A CRITICAL LOOK AT THE APPLICATION OF EDNA BARCODING TO BIOMONITORING�������������������������������������� 277

Carolina Penalva-Arana, Erik Pilgrim, John Martinson 

ASSESSING THE RELATIONSHIP BETWEEN FORESTS AND WATER IN THE HIGH ROCK LAKE 

WATERSHED OF NORTH CAROLINA����������������������������������������������������������������������������������������������������������������� 278

Tom A. Gerow, Jr., David G. Jones, and Wenwu Tang

INTEGRATED RESEARCH – WATER QUALITY, SOCIOLOGICAL, ECONOMIC, AND MODELING – 

IN A REGULATED WATERSHED: JORDAN LAKE, NC������������������������������������������������������������������������������������������ 279

Deanna Osmond, Mazdak Arabi, Caela O’Connell, Dana Hoag, Dan Line, Marzieh Motallebi, Ali Tasdighi

WATER USE EFFICIENCY AT BASIN AND FARM SCALES����������������������������������������������������������������������������������� 280

Ehsan Goodarzi, Lotfollah Ziaei, Saeid Eslamian

GROUNDWATER AVAILABILITY IN THE CROUCH BRANCH AND MCQUEEN BRANCH AQUIFERS, 

CHESTERFIELD COUNTY, SOUTH CAROLINA, 1900–2012 ��������������������������������������������������������������������������������� 281

Bruce Campbell, James E. Landmeyer

DEVELOPING A DROUGHT EARLY WARNING INFORMATION SYSTEM FOR COASTAL ECOSYSTEMS 

IN THE CAROLINAS������������������������������������������������������������������������������������������������������������������������������������������ 282

Kirsten Lackstrom, Amanda Brennan, Paul Conrads, Lisa Darby, Kristin Dow, Daniel Tufford

PRECIPITATION PARTITIONING IN SHORT ROTATION BIOENERGY CROPS: IMPLICATIONS FOR 

DOWNSTREAM WATER AVAILABILITY �������������������������������������������������������������������������������������������������������������� 283

Peter Caldwell, Chelcy F. Miniat, Doug Aubrey, Rhett Jackson, Jeff McDonnell

VARIATIONS IN CANOPY AND LITTER INTERCEPTION ACROSS A FOREST CHRONOSEQUENCE 

IN THE SOUTHERN APPALACHIAN MOUNTAINS����������������������������������������������������������������������������������������������� 284

Steven T. Brantley, Paul V. Bolstad, Stephanie H. Laseter, A. Christopher Oishi, Kimberly A. Novick, Chelcy F. Miniat

RESTORATION OF SOUTHERN APPALACHIAN RIPARIAN FORESTS AFFECTED BY EASTERN 

HEMLOCK MORTALITY ������������������������������������������������������������������������������������������������������������������������������������ 285

Katherine Elliott, Chelcy F. Miniat, Jennifer Knoepp, Michael A. Crump, C. Rhett Jackson

PHYSIOLOGICAL RESPONSES OF EASTERN HEMLOCK (TSUGA CANADENSIS) TO BIOLOGICAL CONTROL 

AND SILVICULTURAL RELEASE: IMPLICATIONS FOR HEMLOCK RESTORATION������������������������������������������������ 286

Chelcy F. Miniat, David Zeitlow, Steven T. Brantley, Albert Mayfield, Rusty Rhea, Robert Jetton, Paul Arnold
Proceedings of the Fifth Interagency Conference on Research in the Watersheds xvii

REGIONAL EFFORTS TO PROMOTE FORESTRY BEST MANAGEMENT PRACTICES: 

A SOUTHERN SUCCESS STORY ....................................................................................................................... 287

Herb Nicholson, John Colberg, Hughes Simpson, Tom Gerow, Wib Owen

WATER USE ASSESSMENTS SUPPORTING COMPANY-SPECIFIC GROWTH AND SUSTAINABILITY GOALS ........ 288

John Beebe

INCREASING ALUMINIUM LEVELS IN NOVA SCOTIA, CANADA.......................................................................... 293

S. MacLeod, S. Ambrose, J. Archibald, T. Clair, J. Minichiello, S. Sterling

PRIORITIZING CATCHMENTS FOR TERRESTRIAL LIMING IN NOVA SCOTIA ...................................................... 294

Marley Geddes, Shannon Sterling

DEVELOPMENT OF A MERCURY LOAD MODEL USING TOPMODEL FLOW SIMULATIONS 

AT McTIER CREEK, SOUTH CAROLINA ............................................................................................................. 295

Stephen T. Benedict, Paul A. Conrads, Toby D. Feaster, Celeste A. Journey, Heather E. Golden, 

Christopher D. Knightes, Gary M. Davis, Paul M. Bradley

SIMULATION OF STREAMFLOW IN THE McTIER CREEK WATERSHED, SOUTH CAROLINA ................................ 296

Toby D. Feaster, Heather E. Golden, Paul A. Conrads, Paul M. Bradley

DEVELOPING THE U.S. GEOLOGICAL SURVEY STREAMSTATS WEB APPLICATION 

FOR SOUTH CAROLINA ................................................................................................................................... 297

Toby D. Feaster, Jimmy M. Clark

USE OF BENEFICIAL BACTERIA TO TREAT NUTRIENTS IN POND WATER ......................................................... 298

Mike Haberland, Salvatore Mangiafico, Debra Haberland

INVESTIGATION OF CO2 AND CH4 EMISSIONS FROM TIDAL FRESHWATER AND NON-TIDAL 

BOTTOMLAND FOREST RIPARIAN ZONES ........................................................................................................ 299

Bryan Farley, Carl Trettin, Craig Allan

IMPACT OF OFF-HIGHWAY VEHICULAR TRAIL SYSTEM ON WATER QUALITY ................................................... 300

Stephanie Laseter, Chelcy Miniat, Randy Fowler, Dick Rightmyer, Ed Hunter

THE AGRICULTURAL CONSERVATION PLANNING FRAMEWORK: A GIS-BASED TOOLBOX TO 

FACILITATE WATERSHED PLANNING AT THE HUC12 SCALE ............................................................................. 301

M.D. Tomer, S.A. Porter, D.E. James, and K.J. Cole

CULVERT DESIGN AND TIDAL MARSH HEALTH ................................................................................................ 302

Jaclyn Daly-Fuchs, Clayton Willis, Pace Wilber

Plenary Session 
2 Headwaters to Estuaries: Advances in Watershed Science and Management

Plenary Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

STRENGTHENING THE SCIENTIFIC FOUNDATION FOR THE 

CLEAN WATER ACT THROUGH FEDERAL PARTNERSHIP 

AND TRANSDISCIPLINARY COLLABORATION

Laurie C. Alexander, William G. Kepner, and David C. Goodrich1

Abstract—The U.S. Environmental Protection Agency’s Office of Research and Development (EPA/ORD) released 

a report, titled Connectivity of Streams and Wetlands to Downstream Waters: A Review and Synthesis of the Scientific 

Evidence, that summarizes more than 1,200 studies from the peer-reviewed scientific literature on the structural and 

functional connectivity of streams and wetlands to downstream waters such as rivers, lakes, reservoirs and estuaries (https://

www.federalregister.gov/articles/2015/01/15/2015-00339/connectivity-of-streams-and-wetlands-to-downstream-waters-areview-and-synthesis-of-the-scientific). The evidence reviewed in this report spans many decades of research into aquatic 

ecosystems and watershed processes. It provides a scientific basis for the Clean Water Rule, which clarifies the definition 

of “waters of the United States” under the Clean Water Act and went into effect on 28 August 2015. As a technical review, 

the ORD report does not consider or set forth legal standards for CWA jurisdiction. Rather, it summarizes current scientific 

understanding of the hydrologic, chemical, and biological connections by which small or temporary streams, nontidal 

wetlands, and open-waters, singly or in aggregate, affect the integrity of waters protected by the Clean Water Act. It is the 

result of a multi-year collaboration by scientists working across disciplinary and organizational boundaries to synthesize 

the best available science in response to evolving policy needs.

INTRODUCTION

The objective of the Clean Water Act (CWA) is to restore 

and maintain the chemical, physical, and biological 

integrity of the nation’s waters. Supreme Court decisions 

in SWANCC (2001) and Rapanos (2006) raised 

questions about the scope of the CWA, and motivated 

new research into the connectivity of waters. In January 

2015 the EPA ORD published a report (US EPA, 2015) 

to inform rulemaking by EPA and the U.S. Army Corps 

of Engineers on the definition of “waters of the United 

States” under the Clean Water Act (CWA). As a technical 

document, this report does not consider or propose legal 

standards or policy options for CWA jurisdiction. Rather, 

it evaluates, summarizes, and synthesizes the available 

peer-reviewed scientific literature to address questions 

about the physical, chemical, and biological connectivity 

and downstream effects of three categories of waters: 

ephemeral, intermittent, and perennial streams; riparian 

or floodplain wetlands and open waters; and wetlands and 

open waters in non-floodplain settings.

METHODS

This report is the product of a transdisciplinary 

collaboration of scientists in the EPA ORD National 

Center for Environmental Assessment, National Health 

and Environmental Effects Research Laboratory, National 

Exposure Research Laboratory, and the United States 

Department of Agriculture’s Agricultural Research 

Service. The authors reviewed and evaluated a large 

body of evidence from peer-reviewed sources that were 

published or in press by December 2014, including 

original research by scientists in federal agencies. The 

review synthesizes a total of 1,355 publications, which 

included 1,150 peer-reviewed journal articles, 120 

scientific books or chapters, and 50 Federal reports. 

Following internal review by EPA and U.S. Army Corps 

of Engineers operational staff, drafts of the report were 

externally peer-reviewed by scientists in government, 

academic, nonprofit, and private industry organizations 

at three different levels: a peer consultation with 11 topic 

experts in February 2011, a contractor-led panel review 

by 11 independent peer reviewers in January 2012, and a 

review by the EPA Science Advisory Board (SAB), which 

1

Laurie C. Alexander, Research Ecologist, U.S. Environmental Protection Agency, Office of Research and Development, Washington, D.C. 20460

William G. Kepner, Research Ecologist, U.S. Environmental Protection Agency, Office of Research and Development, Las Vegas, NV 89119

David C. Goodrich, Research Hydraulic Engineer, USDA-Agricultural Research Service, Southwest Watershed Research Center, Tucson, AZ 85719
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 3

Plenary Session

convened public meetings of a 27-member panel in 2013 

and 2014. The level of peer review exceeded standards 

established by OMB (2004). All peer-review panels 

included Federal partners, who also provided comments 

during Interagency review. In addition, 133,100 comments 

from the public were received through the docket (Docket 

No. EPA-HQ-OA-2013-0582). Comments from all 

sources were considered and used to improve the clarity 

and scientific rigor of the document.

CONCLUSIONS 

The final report contains five major conclusions, 

summarized here:

1. The scientific literature unequivocally demonstrates 

that streams, regardless of their size or frequency of 

flow, are connected to downstream waters and strongly 

influence their function.

2. The scientific literature clearly shows that wetlands 

and open waters in riparian areas (transitional areas 

between terrestrial and aquatic ecosystems) and 

floodplains are physically, chemically, and biologically 

integrated with rivers via functions that improve 

downstream water quality. These systems act as 

effective buffers to protect downstream waters from 

pollution and are essential components of river food 

webs. 

3. There is ample evidence that many wetlands and 

open waters located outside of riparian areas and 

floodplains, even when lacking surface water 

connections, provide physical, chemical, and biological 

functions that could affect the integrity of downstream 

waters. Some potential benefits of these wetlands are 

due to their isolation rather than their connectivity. 

Evaluations of the connectivity and effects of 

individual wetlands or groups of wetlands are possible 

through case-by-case analysis.

4. Variations in the degree of connectivity are determined 

by the physical, chemical and biological environment, 

and by human activities. These variations support a 

range of stream and wetland functions that affect the 

integrity and sustainability of downstream waters.

5. The literature strongly supports the conclusion that the 

incremental contributions of individual streams and 

wetlands are cumulative across entire watersheds, and 

their effects on downstream waters should be evaluated 

within the context of other streams and wetlands in that 

watershed.

ACKNOWLEDGMENTS

This report was funded through the EPA ORD. It has been 

subjected to Agency review and approved for publication.

We are indebted to the report co-authors and the many 

national experts who reviewed the drafts, provided 

comments and additions, and helped us in our effort 

to synthesize the best available science in response to 

evolving policy needs.

LITERATURE CITED

Office of Management and Budget (OMB). 2004. Final 

information quality bulletin for peer review (Memorandum 

M-05-03). Office of Management and Budget, 

Washington, DC. (https://www.whitehouse.gov/omb/

memoranda_fy2005_m05-03).

Rapanos v. United States, 547 U.S. 715 (2006). https://supreme.

justia.com/cases/federal/us/547/715/ 

Solid Waste Agency of Northern Cook County (SWANCC) 

v. U.S. Army Corps of Engineers. 531 U.S. 159 (2001). 

https://supreme.justia.com/cases/federal/us/531/159/

case.html

U.S. Environmental Protection Agency (US EPA). 2015. 

Connectivity of Streams and Wetlands to Downstream 

Waters: A Review and Synthesis of the Scientific Evidence. 

EPA/600-R-14/475F, 408pp (http://cfpub.epa.gov/ncea/cfm/

recordisplay.cfm?deid=296414).

Managing Forested Wetlands in 

Coastal Watersheds
6 Headwaters to Estuaries: Advances in Watershed Science and Management

Managing Forested Wetlands in Coastal Watersheds

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

OVERVIEW OF FOREST CONDITIONS

IN COASTAL COUNTIES

Eunice A. Padley, Sonja N. Oswalt1

Forest Inventory and Analysis (FIA) data were summarized for southeastern U.S. 

counties which had their centroids within coastal watersheds (8-digit HUCs). 

Coastlines from Texas through North Carolina were included in the analysis, and 

two time periods were compared (1997-2002 and 2011-2013). Forestland area 

within the coastal counties totaled 45.3 and 45.9 million acres at the two time 

periods, but the difference was not statistically significant. Among FIA forest 

type groups represented in the study area, only loblolly/shortleaf pine showed 

significant differences. Changes in the extent of wetland forest could not be 

determined from the FIA dataset. 

1

Eunice Padley, National Forester, USDA Natural Resources Conservation Service, Washington, DC 20250

Sonja Oswalt, Forest Resource Analyst, USDA Forest Service, Southern Research Station, Knoxville, TN 37919
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 7

Managing Forested Wetlands in Coastal Watersheds

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

REGULATORY OVERVIEW

Robert Huff1

Section 404 of the Clean Water Act (CWA) (33 U.S.C. 1344) authorizes the Secretary of the 

Army, acting through the Chief of Engineers, to issue permits, after notice and opportunity for 

public hearing, for the discharge of dredged or fill material into the waters of the United States 

at specified disposal sites. Under the CWA, it is unlawful to discharge dredged or fill material 

into waters of the United States without first receiving authorization from the Corps, unless 

the discharge is covered under an exemption.

The basis of the CWA was enacted in 1948 and was called the Federal Water Pollution 

Control Act, but the Act was significantly reorganized and expanded in 1972. “Clean Water 

Act” became the Act’s common name with amendments in 1977. The amendments included a 

set of six exemptions from permitting requirements, which can be found under Section 404(f) 

of the CWA.

One of the six exemptions from permitting requirements listed under Section 404(f) of 

the CWA is normal farming, silviculture and ranching activities such as plowing, seeding, 

cultivating, minor drainage and harvesting for the production of food, fiber and forest 

products. To qualify under this exemption, the activity must be part of an established (i.e. 

ongoing) farming, silviculture, or ranching operation and not be part of an activity whose 

purpose is to convert an area of waters of the United States into a use to which it was 

not previously subject (i.e. change of use, silviculture to farming), and/or the immediate 

or gradual conversion of a wetland to a non-wetland. If a change of use occurs and the 

activity impairs the flow or circulation of waters of the U.S., that activity shall be required 

to have a permit under Section 404(f)(2) of the CWA, commonly referred to as the 

“recapture provision.”

1

Forester, US Army Corps of Engineers, Conway, SC 29526
8 Headwaters to Estuaries: Advances in Watershed Science and Management

Managing Forested Wetlands in Coastal Watersheds

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

LOSS OF FORESTED WETLANDS - 

QUESTIONS, ANSWERS, AND MORE QUESTIONS

Susan-Marie Stedman1

The most recent study (2004 – 2009) on the Status and Trends of Wetlands in the Coastal 

Watersheds of the US indicates a connection between forested wetland loss and areas being 

used for silviculture. Many questions have been raised about this trend, including how the 

Status and Tends methodology identifies wetlands and wetland loss, how “minor drainage” 

is practiced on silvicultural lands, and why only some of the forested wetlands in silviculture 

become uplands. Watershed-scale pilot studies conducted as part of the National Ocean 

Policy’s Implementation Plan have revealed that local and regional changes in hydrology may 

play a role in the losses of forested wetlands, and that silviculture may be an intermediate 

phase in the loss of forested wetlands to development.

1

Fishery Biologist, National Oceanic and Atmospheric Administration Fisheries, Silver Spring, MD 20910
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 9

Managing Forested Wetlands in Coastal Watersheds

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

EMERGING ISSUES WITH SILVICULTURE 

PRACTICES IN WETLANDS

Mike Wylie1

Silviculture activities in wetlands involving discharges of dredge and/or fill material have 

been exempt from Clean Water Act (CWA) permits after the 1975 amendments to the 

CWA which were phased in by July 1977. However, Congress mandated that all exempt 

silviculture activities in wetlands maintain wetland hydrology. Congress also allowed minor 

drainage activities in wetland silviculture sites so landowners could plant, maintain and 

harvest timber sites. In the southeast there are two predominate wetland, silviculture classes 

– pine plantations and hardwood forests. Minor drainage to support the management of 

pine plantations while ensuring CWA wetland status is an emerging silviculture issue in the 

southeast. Recently, volatile timber prices, rising raw land prices, agricultural conversions and 

developmental pressure, have led to landowners converting silviculture tracts to other land 

uses. Typically, the only time federal regulators access a silviculture tract is when a change 

of land use is contemplated and wetland delineation is requested by the landowner. Many of 

these silviculture tracts contain wetlands that no longer exhibit wetland hydrology. Moreover, 

conducting wetland delineations on silviculture sites can be difficult due to: land ownership 

changes, case law, statute of limitations, drainage conducted before the CWA 1975 statutory 

changes, drainage ditches, imprecise regulatory definitions, and off-site disturbances. 

1

Wetland Ecologist, US Environmental Protection Agency, Atlanta, GA 30303
10 Headwaters to Estuaries: Advances in Watershed Science and Management

Managing Forested Wetlands in Coastal Watersheds

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

EFFECT OF MINOR DRAINAGE ON HYDROLOGY 

OF FORESTED WETLANDS

Wayne Skaggs, George Chescheir1

A simulation study was conducted to determine the impacts of minor drainage for silviculture 

on wetland hydrology. Long‐term DRAINMOD simulations were used to determine the 

threshold drainage intensity (ditch depth and spacing) that removes wetland hydrology from 

forested wetlands. Analyses were conducted for 13 soil series and profile combinations at 

ten locations in the Atlantic and Gulf coastal states. Threshold ditch spacings (LT) were 

obtained for all combinations of soil profiles and locations. Analysis of the results showed 

that LT (m) can be approximated as LT = C T, where T (cm2 h‐1) is the horizontal hydraulic 

transmissivity of the soil profile, and C is a coefficient dependent on ditch depth and 

geographic location. The threshold spacings can be used as benchmarks to directly evaluate 

the impact of drainage alternatives on wetland hydrology. Lateral impacts were determined for 

a 0.9 m (3 feet) deep drainage ditch for all soils and locations considered. 

1

Wayne Skaggs, Professor of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695

George Chescheir, Professor of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 11

Managing Forested Wetlands in Coastal Watersheds

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

SOUTH CAROLINA’S BEST MANAGEMENT PRACTICES 

FOR FORESTY FOR MINOR DRAINAGE

Tonya Smith, Herb Nicholson1

Minor drainage is normally used to facilitate regeneration and timber harvesting by 

temporarily removing surface water from inundated forestland. Specific ditch depth and 

spacing recommendations are not listed in our manual, as each site is individually evaluated. 

As with any silvicultural practices conducted in wetlands, it is important to avoid converting 

a wetland site to an upland site. SC BMPs are designed to avoid this conversion and 

enable wetlands to remain forested into the future while protecting water quality and the 

wetland ecosystem.

1

Tonya Smith, Best Management Practices Forester, South Carolina Forestry Commission, Kingstree, SC 29556

Herb Nicholson, Environmental Management, South Carolina Forestry Commission, Kingstree, SC 29556

Multicollabortive Research on 

Turkey Creek Watershed and Beyond: 

10-Year Accomplishments and New Directions
14 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

COASTAL PLAIN SOILS AND GEOMORPHOLOGY: 

A KEY TO UNDERSTANDING FOREST HYDROLOGY 

Thomas M. Williams and Devendra M. Amatya1

Abstract—In the 1950s, Coile published a simple classification of southeastern coastal soils using three characteristics: 

drainage class, sub-soil depth, and sub-soil texture. These ideas were used by Warren Stuck and Bill Smith to produce 

a matrix of soils with drainage class as one ordinate and subsoil texture as the second for the South Carolina coastal 

plain. Soils with sandy clay loam sub-soils (the most widely distributed soils on the coastal plain) were further divided 

by sub-soil depth into three categories: > 40 inches, 20-40 inches, and <20 inches. In 1974 Donald Colquhoun classified 

geomorphology of the lower SC coastal plain by relationship to seven former marine terraces. Sediments were associated 

with beach, offshore, or back barrier deposits while river valleys were associated with either fluvial or estuarine deposits. 

Using GIS, soils in the matrix can be mapped to the geomorphic features revealing a geomorphic explanation for the 

distribution of soils across the coastal plain. Beach and offshore deposits have sand throughout the soil profile, while 

back barrier deposits tend to have clay or clay loams. Fluvial terrace deposits have sandy clay loam sub-soils while some 

estuarine valleys have entirely organic soil profiles. Classification of drainage class is directly related to the average water 

table depth of soils. Within a single sub-soil type (sands), average water table depth is directly predicted by drainage class. 

Soil subsurface type also greatly influences drainable porosity (the porosity that is filled or emptied by a small change in 

water table). Geochemical analysis of flows on sandy subsoil (near Georgetown) and clay sub-soils on Turkey Creek and 

Watershed 80 (near Charleston) show this difference in drainable porosity and water table fluctuations to be related to the 

source of storm runoff. Sandy sub-soils have higher drainable porosity, smaller water table fluctuations, and a prevalence of 

soil water chemistry in runoff. Clay sub-soils have lower drainable porosity, greater water table fluctuation as a response to 

rainfall and ET, and stream runoff chemistry more similar to that of rainwater. 

INTRODUCTION

Forest hydrology has been widely studied in the 

southeastern Coastal Plain that is typified by watersheds 

with shallow water table depths due to the mild slopes. 

Depth of the water table is an important determinant of 

not only forest productivity but also of the volume of 

runoff (Elsheman and others 1994, Harder and others 

2007, Williams 1979, 2007). The southeastern coastal 

plain is geologically young and fluvial processes have 

had little time to develop drainage patterns, resulting 

in landscapes dominated by older estuarine and marine 

geomorphic features. Buol (1973) found soils on these 

old marine features formed catenae (catena being 

adjacent soil series in the same parent materials that form 

a soil drainage sequence) with best drained soils near 

streams and most poorly drained at inter-stream divides 

opposite of what is expected in areas with mature fluvial 

geomorphology. Prior to the advent of Light Detection 

and Ranging (LIDAR) technology, much of the subtle 

elevation differences in soil setting were not obvious, 

making interpretation of spatial distribution of soils 

very difficult. 

Soil properties are also a very important aspect of forest 

productivity. Coile (1952) established that soil texture, 

depth to a heavy textured layer, and soil drainage (depth 

to water table) were the main factors that predicted forest 

growth rates. Using similar principles, Warren Stuck 

(1976) presented a simple classification chart of South 

Carolina coastal soil series. All soil series listed on that 

chart were arranged into six drainage classes and seven 

subsurface texture/depth classes. The six drainage classes 

were excessively-well, well, moderately-well, somewhatpoorly, poorly, and very-poorly drained. Texture classes 

were classified as: sand, 10-18 percent clay, 18-35 percent 

clay, 35-45 percent clay, and >45 percent clay. Since 

many coastal sub-soils contained 18-35 percent clay, these 

were further divided into depth of sub-surface layer of 

> 40 inches (102 cm), 20-40 inches (51-102 cm), and 

< 20 inches (51 cm). 

South Carolina coastal geomorphology consists of eleven 

former marine terraces (Cooke 1936, Colquhoun 1974) 

that represent former stands of sea level. Colquhoun 

(1974) mapped the eastern most six of these terraces with 

interpretation of geomorphic features associated with rise 

or fall of sea level. Terrace features were either offshore 

1

Thomas M. Williams, Professor Emeritus, Baruch Institute of Coastal Ecology and Forest Science, Georgetown, SC 29442

Devendra M. Amatya, Research Hydrologist, USDA Forest Service, Center for Forested Wetlands Research, Cordesville, SC 29434
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 15

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

deposits, beach deposits, or back barrier marsh deposits. 

Riverine deposits were either floodplain, estuarine, or 

deltaic deposits. 

Current soil surveys and GIS technology allow a 

qualitative comparison of that simple soil classification 

to the classes of geomorphic feature, which were mapped 

for the South Carolina coast. The objective of this paper 

present the techniques used to make such a comparison 

and to examine the hydrologic implications of such a 

soil classification.

PROCEDURES

Soil surveys of the coastal South Carolina counties 

were obtained from the South Carolina Department of 

Natural Resources (SCDNR 2013) along with survey 

maps for each coastal quadrangle. These soil polygons 

were then merged by series to produce a continuous 

map of the coastal plain soils within a GIS environment 

(ARC-GIS 10.1).

GIS was used to create an overlay of the Colquhoun 

(1974) map to the present soil survey. The original map, 

1:1,000,000 scale, was photocopied in page-sized blocks. 

These blocks were then hand colored, mosaicked, and 

photographed as a 35 mm slide in 1980. In 2014, the slide 

was scanned (1200 dpi) and converted to a digital image 

file. The original map included lines representing major 

highways present in the 1970s. A current digital road GIS 

layer (1:24,000) was used to georeference the image of 

the original map. 

Long-term estimates of average water table depth and 

standard deviations were collected from Williams (2007) 

for a study site in Hobcaw Barony site near Georgetown 

and Williams and Amatya (2010) ) for the Turkey Creek 

watershed at the Santee Experimental Forest. These values 

were placed within the soil classification matrix where the 

studied soil series occurred. Likewise, drainable porosity 

values were collected from Williams (1978) and Harder 

and others (2007) and again placed in the appropriate 

matrix block. 

RESULTS 

Soil surveys included a number of soil series not included 

on the chart presented by Stuck (1976). The original 

chart was modified in several ways to accommodate 

the additional soils. The break points in soil texture 

corresponded to standard soil texture names: sands < 10 

percent clay, sandy loam 19-18 percent clay, sandy clay 

loam 18-35 percent clay, clay loam or sandy clay 35-45 

percent clay, and clay > 45 percent. Changing to named 

categories also revealed a shortcoming of the original in 

that only clay content was considered. Soils with silt loam 

or silt sub-soils were undifferentiated from sandy loams. 

There are 13 current series with such subsoils, requiring 

an additional subsurface texture class. The original chart 

had only six drainage classes, yet now there are six 

series that are classed as somewhat excessively drained, 

requiring an additional class. Also, the original very 

poorly drained class included both mineral and organic 

soils. These were separated by adding an additional very 

poorly drained organic class. The original chart has been 

modified to be an 8x8 matrix of drainage class and subsoil texture (Fig. 1).

The classification in Figure 1 groups 194 separate soil 

series into 64 categories. Nineteen of those categories are 

blank since excessive drainage does not occur on soils 

with more than 18 percent clay in the subsoil, and there 

are relatively few organic soils or soils with sub-surface 

clay more than 102 cm deep. 

Despite the blank cells, representing the relationships 

among 194 soils in 45 separate classes on a single map 

still presents a challenge. The key method to accomplish 

that was to use systematic color variation among classes. 

Colors were assigned to cells by hue, saturation, and 

value (HSV) within a Geographic Information System 

(GIS) polygon of symbol properties. Drainage class 

was designated by values with: excessive well (100), 

somewhat excessively (93), well (85), moderately well 

(77), somewhat poorly (67), poorly (54), very poorly 

mineral (24), very poorly organic (0). Subsoil texture 

was designated by hue with: clay (0)- red, clay loamsandy clay ( 28) orange, sand (62)- yellow, sandy loam 

(68), greenish yellow, sandy clay loam >102 cm – 91- 

yellowish green, sandy clay loam 51-102cm- 138-green, 

sandy clay loam <51cm -155-blueish green, silt loam 

-288-purple. 

 Despite a large number of highway intersections and 

a small root mean square error of rectification, the 

geomorphic overlay could not be evaluated for geospatial 

accuracy due to the multiple distortions induced by the 

many manipulations of the image that we performed. 

DISCUSSION

Soils and Geomorphology

By refining the drainage and sub-surface texture 

classification to include an extra drainage class of very 

poorly drained organic soils and an extra texture class to 

include subsoils high in silt, all soils mapped on the South 

Carolina Coastal plain were included in one of the 64 

resulting categories (Fig. 1). Additionally, a colorization 

scheme using the same classification scheme that also 

included both hue for texture and value for drainage was 

incorporated in a map of South Carolina coastal plain 

soils (Fig. 2). 

 The resulting coastal plain soils map includes a number 

of prominent features that are similar to features of 

coastal terrace geomorphology. Colquhoun (1974) revised 

Cooke’s (1936) earlier mapping of coastal terraces into 

11 separate terraces (Fig. 3 insert). He also interpreted 
16 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

coastal geomorphic features to reflect features associated 

with rising or falling sea level. Rising sea level features 

are common to the present coast of prominent barrier 

beach deposits, with salt marsh plains landward, and 

sloping offshore plains seaward. Falling sea level 

produced mainly erosional reworking of former rising 

deposits. Riverine deposits included overbank floodplain 

deposits, estuarine, and deltaic deposits (Fig. 3). 

Sandy features are prominent as both riverine dunes 

(yellow on both maps) and barrier beaches (red in Fig. 3, 

yellow in Fig. 2). The riverine dunes are one of the 

few prominent features deposited during low sea level, 

associated with dry glacial periods (Ivester and Leigh 

2003). Barrier beaches of the Talbot and Pamlico terraces 

are also well defined with sandy soils, although with less 

excessively well drained soil than the riverine dunes. 

Heavy textured subsoils (orange and red in Fig. 2) tend 

to be associated with former salt marsh plain deposits 

(brown in Fig. 3) and also estuarine deposits in the 

inland terraces of the Pee Dee floodplain. On the Santee 

floodplain, similar terraces are more likely to have silt in 

the subsoil, although some silt is also found on the more 

inland Pee Dee floodplain terraces. Marsh plains are 

widespread in the southern coastal plain while in the

northern coastal plain marsh, plains tend to be located 

just east of many barrier sands, being the farthest western 

extent of the next lower marine terrace. 

Sandy clay loam subsoils tend to be associated with 

former river deltas (greens on both Fig. 2&3). These are 

quite extensive on the oldest terraces that Colquhoun 

(1974) mapped. In Figure 2, these soils are also more 

prominent on the older terraces located between 

Wicomico and the sand hills. On the lower coastal plain, 

the most pronounced delta is south of the Santee River 

above the Talbot terrace. The Francis Marion National 

Forest (FMNF) is located on this feature and the marsh 

plain just to the northwest. The distribution of soils and 

geomorphology are comparable in the area surrounding 

the Turkey Creek watershed (Fig. 4).

Soils and Hydrology

The position of the water table has been shown to greatly 

control the hydrology of coastal forested watersheds 

(Elsheman and others 1994, Harder and others 2007, 

Williams 1979, 2007, Amatya and other 1996, Amatya 

and Skaggs 2001). Forest hydrology research on the 

lower coastal plain has been the focus of three longterm research areas; the Santee Experimental Forest, the 

Figure 1—South Carolina coastal soils arranged by drainage class, subsoil texture and depth of subsurface. 

Individual cells are colored with hues that reflect sub-surface texture and values that reflect drainage class.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 17

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Figure 2—Map of South Carolina Coastal plain soils. Soil classes are colored to match cells 

in figure using soil series names. 
18 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Figure 3—Geomorphic terraces of coastal South Carolina. Inset map shows position of coastal 

plain terraces from Cooke (1936) and Colquhoun (1974) while map represents individual features of 

the lower coastal terraces. 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 19

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Baruch Institute of Coastal Ecology and Forest Science 

in South Carolina, and the Weyerhaeuser Carteret tract 

in North Carolina. Long-term water table estimates 

only a few of the categories in Figure 1 at those sites. 

Average water table depths and standard deviations are 

given for those in Figure 5. These data tend to show that 

drainage class reflects average water table depth quite 

well, especially for similar subsoil types. Between types, 

there seems to be a tendency for deeper average water 

table depths for the same drainage class as the subsoil 

texture becomes heavier. As subsoil texture becomes 

heavier, the variance of the water table elevation increases 

with the coefficient of variation near 100 percent for 

most of the heavy textured subsoils. Since drainage class 

includes both average water table and probability a soil 

will saturate, heavier textured soils with the similar water 

tables would tend to be in a wetter drainage class due to 

the increased variability.

Drainable porosity (the portion of soil pore space that 

drains with a small change in water table depth) has 

only been determined on five classes (Williams 1978, 

Harder and others 2007, Amataya and others 1996) but 

tend to reinforce the tendency seen in variance of the 

water table depth. Sandy subsoils have porosity values 

> 0.1 (10 percent), sandy clay loam at 0.09 (9 percent) 

while clay loam and clay are 0.07 (7 percent) and 0.05 

(5 percent), respectively. This implies that 1 mm of rain 

or drainage on a sandy subsoil will change the water table 

Figure 4—Map of Turkey Creek watershed outline on soils as in 

Figure 2 and on geomorphic features in Figure 3. Note the higher 

resolution of the county soil maps compared to the statewide 

geomorphic map.
20 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

7-9 mm while 1 mm on clay subsoil will change the water 

table 20 mm. 

Subsoil texture may also impact the processes by which 

runoff is produced for coastal plain watersheds. Griffin 

and others (2014) found runoff from watersheds with 

heavy textured subsoils (same as Harder and others 2007) 

had chemistry similar to rainwater (45-67 percent), while 

watersheds with sandy subsoil produced runoff with 

chemistry 56-61 percent similar to groundwater. They 

suggested that the difference was due to a faster saturation 

of the heavy textured subsoil. Drainable porosity values 

of 5 percent on the heavy textured soil would suggest less 

rain would be required to saturate such soils, compared to 

10-11 percent for sandy subsoils.

LITERATURE CITED 

Amatya, D.M.; Skaggs, R.W. 2011. Long-term hydrology and water 

quality of a drained pine plantation in North Carolina, USA. 

Transactions of the ASABE. 54(6): 2087-2098

Amatya, D.M.; Callahan, T.J.; Trettin, C.C.; Adecki-Pawlik, A. 

2009. Hydrologic and water quality monitoring on Turkey Creek 

Watershed, Francis Marion National Forest, SC. ASABE paper # 09-

5999, prepared for presentation at the June 21-24, Annual ASABE 

International Meeting, Reno, NV.

Amatya, D.M., Skaggs, R.W.; Gregory, J.D. 1996. Effects of controlled 

drainage on the hydrology of a drained pine plantation in the North 

Carolina Coastal Plains. Journal of Hydrology. 181(1996): 211-232.

Buol, S.W., ed. 1973. Soils of the Southern United States and Puerto 

Rico. Agricultural Experimental Stations of the Southern United 

States and Puerto Rico Land Grant Universities, Southern 

Cooperative Series, Fort Worth, TX. Bulletin No. 174.

Coile, T.S. 1952. Soil and the growth of forests. Advances in Agronomy. 

4: 329-398.

Colquhoun, D.J. 1974. Cyclic surficial stratigraphic units of the Middle 

and Lower Coastal Plain, central South Carolina. In: Post-Miocene 

stratigraphy, central and southern Atlantic Coastal Plain. Logan, UT: 

Utah State University Press.

Figure 5—A reproduction of the cells in Figure 1, with average water table depths of soils that have data for longterm water table averages. Five cells also have data on the value of drainable porosity, that portion of total soil 

volume that drains with a small change in water table. 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 21

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Cooke, C.Q. 1936. Geology of the Coastal Plain of South Carolina. 

Bulletin 867. US Geological Survey, U.S. Government Printing 

Office, Washington, DC.

Eshleman, K.N.; Pollard, J.S.; O’Brien, A.K. 1994. Interactions between 

groundwater and surface water in a Virginia coastal plain watershed. 

1. Hydrological flowpaths. Hydrological Processes. 8(5): 389-410.

Griffin, M.P.; Callahan, T.J.; Vulava, V.M.; Williams, T.M. 2014. Stormevent flow pathways in lower coastal plain forested watersheds of 

the southeastern United States. Water Resources Research. 50(10): 

8265-8280.

Harder, S.V.; Amatya, D.M.; Callahan, T.J.; Trettin, C.C.; Hakkila, J. 

2007. Hydrology and water budget for a forested Atlantic coastal 

plain watershed, South Carolina. Journal of the American Water 

Resources Association. 43(3): 563-575.

Ivester, A.H.; Leigh, D.S. 2003. Riverine dunes on the Coastal Plain of 

Georgia, USA. Geomorphology. 51: 289-311. 

SCDNR 2013. South Carolina Department of Natural Resources, DNR 

GIS Data Clearing House online at http://www.dnr.sc.gov/GIS/

gisdownload.html, (Data accessed on Oct 15, 2013).

Stuck, W.W. 1976. Rough key to South Carolina soil series. 

(unpublished handout). Sixth Southern Forest Soils Workshop, 

Charleston, SC, Oct. 19-21.

Williams, T.M.; Amatya, D.M. 2010. Long-term shallow groundwater 

studies in the coastal plain. In: Opportunities and challenges: 

Proceeding of the second South Carolina water resources conference. 

Columbia SC, Oct 13-14. 

 Williams, T.M. 1978. Response of shallow water tables to rainfall. In: 

Balmer, W.E., ed. Proceedings: Soil moisture - site productivity 

symposium. USDA Forest Service, Southeastern State and Private 

Forestry: 366-370. 

Williams, T.M. 1979. Implications of hydrologic response to the practice 

of forestry on coastal forests. In: Smith, W.H., ed. Proceedings: 

Forest practice and water. 1979 Annual Meeting, Florida Section, 

Society of American Foresters: 92-102.

Williams, T. M. 2007. Evidence of runoff production mechanisms in low 

gradient coastal forested watersheds, Paper presented at 2007 ASAE 

Annual Meeting, American Society of Agricultural and Biological 

Engineering, St. Joseph, MI.
22 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

TEN YEARS OF REAL-TIME STREAMFLOW GAGING OF 

TURKEY CREEK – WHERE WE HAVE BEEN AND 

WHERE WE ARE GOING

Paul Conrads, Devendra Amatya1

The Turkey Creek watershed is a third-order coastal plain stream system draining an area 

of approximately 5,240 hectares of the Francis Marion National Forest and located about 

37 miles northwest of Charleston near Huger, South Carolina. The U.S. Department of 

Agriculture (USDA) Forest Service maintained a streamflow gaging station on Turkey Creek 

from 1964 to 1981. After the substantial impact to the National Forest from Hurricane Hugo 

in 1989, researchers recognized the importance of re-establishing a streamflow monitoring 

station on Turkey Creek. The U.S. Geological Survey, in cooperation with the USDA Forest 

Service and the College of Charleston, established a stream gaging station in Turkey Creek 

in February 2005 (http://waterdata.usgs.gov/sc/nwis/uv?site_no=02172035). The gage is 

located on the downstream side of the U.S. Highway 41N Bridge approximately one-half 

mile upstream from the discontinued Forest Service gaging station. Since the gage was reestablished in 2005, 84 streamflow measurements have been made to establish and confirm 

the stage-streamflow relation (rating) for the station. Over the ten-year streamflow record, 

average annual streamflow has varied from a minimum of 1.32 cubic feet per second (ft3/s) 

to a maximum of 28.9 ft3/s. The peak streamflow of 1,470 ft3/s occurred on October 25, 

2008. The long-term streamflow data for Turkey Creek provides a basis for understanding 

natural variability, reducing uncertainty in model inputs and parameter estimation, and 

developing new hypotheses about hydrological and ecological functions of coastal plain 

forested landscapes. Recent research interests in tidal freshwater forested wetlands (TFFW) 

have included the downstream reaches of the Turkey Creek that transition to TFFW. The 

extent of tidal effects is temporally variable and results from changing upland streamflow 

conditions, coastal water levels, and tide cycles. For the TFFW, the riparian water table levels 

result from precipitation, upland flow, and downstream tidal exchange. The streamflow data 

from the Turkey Creek gaging station will provide critical data to understanding the dynamic 

downstream tidal response and its implications to eco-hydrologic functions and processes. 

The presentation will evaluate the 10 years of streamflow and precipitation data, describe 

methods of estimating high flood streamflows, compare Turkey Creek to other coastal plain 

watersheds, and describe the complexity of downstream flows in the riparian areas of TFFW.

1

Paul Conrads, Surface Water Specialist, US Geological Survey, Columbia, SC 29036

Devendra Amatya, Research Hydrologist, USDA Forest Service, Center for Forested Wetlands Research, Cordesville, SC 29434
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 23

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

SYNTHESIS OF 10-YEARS OF ECOHYDROLOGIC STUDIES

ON TURKEY CREEK WATERSHED 

Devendra Amatya, Timothy Callahan, and Carl Trettin1

Abstract—Since the establishment of a collaborative study 10 years ago, research on the third-order, 5240 ha forested 

Turkey Creek watershed in South Carolina’s coastal plain has advanced the understanding of rainfall-runoff relationships, 

stream hydrograph characteristics, and water table dynamics for dominant soil types. Surface water dynamics were shown 

to be regulated primarily by the water table, which is dependent upon precipitation and evapotranspiration. The baseflow 

is, however, highly variable, resulting in zero streamflow about one-third of the time, on average. These processes regulate 

upland freshwater runoff and mediate material export into the tidally influenced larger river downstream. Analysis of preand post-Hurricane Hugo streamflow data showed the resiliency of this coastal forest to extreme events. A high-resolution 

LiDAR-based digital elevation model (DEM) was shown to have increased accuracy in drainage area delineation on this 

low-gradient coastal plain compared to available topographic maps and DEMs, potentially influencing site hydrology and 

engineering designs. 

INTRODUCTION

Long-term monitoring and datasets from watersheds 

provide an important opportunity for advancing our 

understanding of forest ecohydrologic processes, 

detecting trends, reducing model and parameter 

uncertainty, and assessing the impacts of climate change 

and anthropogenic and natural disturbances on water 

quantity and quality (Algerich and others 2013; Amatya 

and Skaggs 2011, Furniss and others 2010, Jayakaran 

and others 2014, Jones and others 2009). Indeed, much 

of our current understanding about the relationships 

among forests, climate and climate variability, and 

streamflow comes from long-term gauged forested 

watersheds within the Forest Service, U.S. Department 

of Agriculture’s Experimental Forests and Ranges (Vose 

and others 2014). However, the preponderance of that 

knowledge and literature is derived from high-energy 

piedmont and mountain watersheds with different 

climate and topography (Endale and others 2006, Ford 

and others 2011, Swank and others 2001, Tajchman 

and others 1997). The low-gradient coastal watersheds 

generally have a lower water yield, lower runoff ratio, and 

higher evapotranspiration (ET) than upland-dominated 

watersheds (Sun and others 2002). Only a very few 

observational studies have been conducted on the forested 

landscapes of the humid semitropical coastal plain in 

the southeastern U.S., with shallow water table soils 

potentially controlling the runoff.

Recent population growth, rapid urbanization, and 

development on the southeastern Atlantic coastal plain 

have prompted regulators, land managers, and researchers 

to try to better understand the functional relationships 

between watershed processes and valued ecosystem 

services (ESS) and their interactions with climate 

and forest resources in order to develop sustainable 

management strategies. To this end, regional stakeholders 

formed the Turkey Creek Watershed Research Initiative 

(TCWRI) in late 2004. The main goal of the TCWRI is 

to identify how land use and climate change could affect 

water availability, flooding, water table, water quality, 

and other associated ESS in the Turkey Creek watershed 

(Amatya and Trettin 2007b). In this way, the TCWRI 

can serve as reference or representative system within the 

rapidly urbanizing landscape of the South Carolina lower 

coastal plain. 

 Through cooperation with multiple interests, the TCWRI 

reestablished a real-time stream monitoring gauge on the 

Turkey Creek watershed (WS 78), headwaters of the East 

Branch of the Cooper River, on the Santee Experimental 

Forest (Fig. 1) (Amatya and others 2005). The 

collaborative approach for conducting ecohydrological 

studies using the monitoring and modeling framework 

for the TCWRI was summarized by Amatya and Trettin 

(2007c). 

The objective of this paper is to synthesize the findings 

of the research since 2005 that have advanced the 

1

Devendra Amatya, Research Hydrologist, USDA Forest Service, Center for Forested Wetlands Research, Cordesville, SC 29434

Timothy Callahan, Associate Professor, College of Charleston, Charleston, SC 29424

Carl Trettin, Research Soil Scientist, USDA Forest Service, Center for Forested Wetlands Research, Cordesville, SC 29434
24 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

knowledge on ecohydrologic processes, including 

watershed characteristics, runoff generation, storm 

event characteristics, water budget, ET, and surface 

and subsurface flows and their pathways, particularly 

on Turkey Creek and similar low-gradient coastal 

watersheds. These include the Hobcaw Barony site 

maintained by Clemson University in Georgetown and 

the Dixie Plantation site maintained by the College of 

Charleston. This approach is based on the early vision 

of understanding water balance, soil moisture, and 

precipitation-runoff relationships at varying scales in 

coastal areas by monitoring experimental watersheds of 

multiple sizes at the Santee Experimental Forest (USDA 

FS 1963, Young 1966, 1968). A chronology of studies 

conducted on the watershed since 2004 is presented in 

Table 1.

WATERSHED DESCRIPTION

The Turkey Creek watershed (WS 78) is a third-order 

blackwater stream system draining approximately 5240 

ha. It is located about 60 km northwest of Charleston, 

South Carolina near Huger, in Berkeley County, South 

Carolina (33° 8’ N, 79° 48’ W) (Fig. 1). WS 78 was 

originally gauged in 1963, and it was monitored until 

1981. The gauging station was recommissioned in late 

2004 with real-time gauges/sensors both for rainfall 

and flow monitoring (http://waterdata.usgs.gov/sc/

nwis/uv?site_no=02172035) (Fig. 1) on SC Highway 

41 N near Huger, in cooperation with the United States 

Geological Survey (USGS), the College of Charleston, 

and the South Carolina Department of Transportation. 

The present gauging station is approximately 800 

m upstream of the original gauging station. WS 78 

was intended to compliment three other lower order 

watersheds (WS 77, WS 80, and WS 79) within the 

Santee Experimental Forest (Fig. 1) to provide a 

basis for large-scale ecohydrological monitoring and 

modeling (Amatya and Trettin 2007b). Conrads and 

Amatya (2015) highlighted the statistics of 10 years of 

streamflow data and emphasized the long-term data as a 

basis for understanding natural variability, testing models 

and reducing their uncertainty, and developing new 

hypotheses.

The elevation of the watershed varies from approximately 

2 m above mean sea level at the stream gauging station 

to 14 m above mean sea level at the headwaters (Haley 

2007) (Fig. 1). The subtropical climate is characteristic 

of the coastal plain, with hot and humid summers and 

moderate winter seasons. The minimum and maximum 

air temperatures, based on a 50-year (1951-2000) record 

at the Santee Experimental Forest, were recorded as 

–8.5 °C and 37.7 °C, respectively, with an average daily 

temperature of 18.4 °C. Annual rainfall at the site varied 

from 830 mm to 1940 mm, with an average of 1370 mm 

 Table 1—Chronology of studies on the Turkey Creek watershed (WS 78)

Year Studies/References 

2007 Hydrologic Modeling using SWAT—Haley (2007), MS Thesis

2007 Forest Hydrologic Research 1) at Santee Experimental Forest—Amatya and Trettin (2007a) and 

2) Turkey Creek Watershed—Amatya and Trettin (2007b) 

2007 Estimates of Annual ET—Amatya and Trettin (2007c)

2007 Flow Dynamics of Three Coastal Forest Watersheds—Amatya and Radecki-Pawlik (2007)

2008 Seasonal Relationships of Rainfall and Runoff—La Torre Torres (2008)

2008 Development of a GIS-based Depressional Storage Capacity Model—Amoah (2008), PhD Dissertation

2009 Hydrology and Water Quality of Turkey Creek Watershed—Amatya et al. (2009)

2010 Outfl ow Characteristics of Turkey Creek watershed—Amatya and Trettin (2010)

2011 Seasonal Rainfall-Runoff Relationships on a Forest Watershed—La Torre Torres and others (2011)

2011 Determination of plant characteristics used in discharge capacity—Miroslaw-Swiatek and Amatya (2011)

2011 Evaluating SWAT Model for a Low-gradient Forest Watershed—Amatya and Jha (2011)

2012 Quantifying Watershed Depression Storage—Amoah and others (2012)

2012 Estimating groundwater recharge in lowland watersheds—Callahan and others (2012)

2012 Groundwater–surface water interactions in a lowland watershed—Garrett and others (2012)

2013 Application of LiDAR data for Hydrologic Assessments—Amatya and others (2013)

2014 Storm-event Flow Pathways in Lower Coastal Plain Forested...—Griffi n et al. (2014)

2014 Hurricane Impacts on a Pair of Coastal Forested Watersheds...—Jayakaran and others (2014)

2014 Assessing various potential ET (PET) methods for forest—Amatya and others (2014)
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 25

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

based on the 50-year (1951-2000) data (Amatya and 

others, 2009). 

 The watershed is underlain by Santee Limestone 

approximately 20 m below ground surface (bgs) in the 

western side of the watershed and about 13 m bgs in the 

eastern area (Williams 2007). Initial groundwater data 

at the site suggest that the Santee Limestone is overlain 

by a dense, approximately 10 m-thick semiconsolidated 

unit (Parkers Ferry Formation). This formation acts as a 

confining layer to groundwater flow between the shallow 

surficial sediments and the deeper Santee Limestone 

only in the watershed’s western portion (Williams 

2007). The watershed is dominated by poorly drained 

soils of the Wahee series (clayey, mixed, thermic Aeric 

Ochraquults) mostly on the northern part (or right bank, 

looking downstream) of the stream and Lenoir series 

(clayey, mixed, thermic Aeric Paleaquults) with shallow 

argillic horizons with less than 3 m depth (NRCS 1980) 

mostly on the southern part (left bank) of the stream. 

Williams and Amatya (2015) presented the soil matrix and 

classifications relating to drainage for the South Carolina 

Coastal plain and their implications to shallow water table 

dynamics that drive the forest hydrology.

Land use within the watershed comprises 44 percent 

pine forest, mostly loblolly (Pinus taeda L.) and longleaf 

(Pinus palustris) pine, 35 percent thinned pine forest, 10 

percent forested wetlands, 8 percent mixed forest, and 3 

percent agricultural, roads, open areas, and impervious 

areas (Haley 2007). Most of the current forests on the 

watershed are a mixture of remnant large trees and 

natural regeneration that is approximately 25 years old, 

regenerated since the area was impacted by Hurricane 

Hugo in 1989 (Hook and others 1991).

Details of the study site and ecohydrologic monitoring 

procedures are described elsewhere (Amatya and Trettin 

2007b, Amatya and others 2009, 2013, Callahan and 

Figure 2-- Daily rainfall and water levels in cm below ground surface for water table wells at three locations in the Turkey 

Creek watershed for the period June 2006 - December 2008 (from Callahan et al., 2012).

Figure 1—Turkey Creek (TC) watershed (WS 78) in green boundary mapped using high-resolution LiDAR 

data in 2011 (Table 1). Blue lines are streams and wetlands based on National Hydrography Dataset data. 

Locations of weather stations, stream gauges, and ground water wells are also shown, including for 

three other adjacent first- (WS 77 and WS 80) and second- (WS 79) order watersheds within the Santee 

Experimental Forest (SEF) (red boundary).
26 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

others 2012, Haley 2007). Table 2 shows the chronology 

of various monitoring installations on the Turkey Creek 

watershed.

DISCUSSION OF WATERSHED STUDIES

Watershed Drainage Area

Amatya and others (2013) demonstrated the effects of 

uncertainty in drainage areas obtained by digital elevation 

models (DEMs) of varying resolution and delineation 

method, starting from the historical period to recent use 

of LiDAR (light detection and ranging), on the average 

annual runoff coefficient (ROC) for this low-gradient 

watershed (Table 3). The authors also highlighted the 

potential effects of lower resolution DEMs on many 

hydrologic monitoring and modeling studies prior to 

LiDAR technology. 

Using the initial (1964) drainage area of only 3240 ha, 

the average ROC for the Turkey Creek watershed was 

estimated to be 0.38 (Table 3). The 2011 drainage area 

of 5240 ha, obtained using new DEMs based on highresolution LiDAR data with field verification for culverts 

and roadbeds, was found to be 27.8 percent smaller 

(Amatya and others 2013) than the 2008 estimate of 

7260 ha obtained by Haley (2007) using 10 m x 10 m 

interpolated DEMs, but only 6.5 percent larger than 

the 2004 area of 4920 ha obtained using 30 m x 30 m 

DEMs (Amatya and Radecki-Pawlik 2007), ultimately 

affecting the calculated average annual ROCs. Without 

considering the effects of culverts in 2011 LiDARbased DEMs, the calculated drainage area was 5880 ha, 

consistent with the USGS area at its gauge site. Maceyka 

and Hansen (2015) recently used LiDAR and highresolution aerial photos of the Francis Marion National 

Forest containing this watershed and found the largest 

changes in georeferencing of streams and legacy water 

management structures, enabling their better mapping. 

Although the LiDAR-based DEM is presently considered 

the most accurate for mapping low-gradient coastal 

plain watersheds with implications for water resources 

management, some potential limitations of software 

used in raw data processing and in watershed delineation 

algorithms should be acknowledged. Furthermore, careful 

inspection of LiDAR data using manual edits and hand 

digitizing with field verification is necessary for accurate 

estimates of drainage areas and stream channels. 

Runoff Dynamics

The runoff generation mechanism on the low-gradient 

coastal watershed is influenced by the position of the 

spatially distributed shallow water table threshold 

(Harder and others 2007, Dai and others 2010, Epps and 

others 2013). Williams and Amatya (2015) reported 

that the most important aspect of forest hydrology 

across the coastal plain is the presence of a shallow 

water table, which influences not only the forest water 

balance as a source for fulfilling ET demand from 

vegetation but also as a determinant of the rainfall that 

becomes streamflow. The author related differences in 

soil-drainable porosity and water table fluctuations on 

sandy subsoil (Georgetown, SC) and clay subsoils on 

Turkey Creek (WS 78) and WS 80 to the source of storm 

Table 2—Chronology of monitoring installation and other activities on the Turkey Creek watershed (WS 78)

Year Month Activities/Disturbances 

1963 November Gauging station established

1964 January Rain and streamfl ow monitoring started

1981 May Streamfl ow monitoring discontinued, records mostly by old technology 

2004 December 1st Cooperators’ meeting to initiate a collaborative research, concurrent with revitalization of the 

new USGS stream and rainfall gauging station upstream of old Highway 41N bridge

2005 March New gauge/sensor moved downstream of new Highway 41N bridge

2005 October Manual monitoring of water physical parameters initiated using EurekaTM Manta sonde

2005 October Installation of a Campbell Scientifi c automated weather station

2006 July Installation of four water table recording wells on Rains, Lenoir, Lynchburg, and Goldsboro soils

2006 June Installation of a Teledyne Isco, Inc. automatic water sampler

2010 October Establishing a new Turkey Creek tributary subwatershed streamfl ow monitoring at Conifer 

Road 

2010 November Establishing a new subwatershed streamfl ow monitoring at Eccles Road

2011 January Establishing a fi fth water table recording well on Wahee soil
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 27

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

runoff. The storm runoff that generally occurs after 

complete saturation of soils depends also upon the spatial 

microtopography or effective surface depressional storage 

as determined by Amoah and others (2012) for this and 

five other lower coastal plain watersheds using the DEMs 

with varying grid resolutions, including the LiDARbased DEM. In comparison to areas with high-gradient 

topography, the coastal flatwood watersheds are slower in 

response, with Turkey Creek flow peaking at about 40 to 

45 hours, on average, with duration of 12 to 14 days, on 

average (Amatya and Trettin 2010, La Torre Torres and 

others 2011; La Torre Torres, 2008). 

Using 13 years (1964-76) of previous data, La Torre 

Torres and others (2011) found a large seasonal variability 

in storm event ROC, potentially due to differences in 

forest evapotranspiration that affected seasonal soil 

moisture conditions. Mean event ROC was higher for 

wet periods and wet antecedent soil moisture conditions 

(based on 5-day and 30-day prior antecedent precipitation 

indices) than for dry periods. The authors suggested that 

antecedent soil moisture and groundwater table levels 

are important seasonal runoff generation mechanisms in 

the coastal soils. The results of storm event hydrograph 

characteristics using data from 2005-08 by Amatya and 

Trettin (2010) indicated a hydrologic recovery of forest 

since its regeneration after Hugo in 1989. The authors 

also suggested that the runoff and peak flow rates are 

dependent upon both the rainfall and its intensity, besides 

the antecedent conditions described better by initial water 

table positions, as recently demonstrated by Epps and 

others (2013) for the adjacent watershed (WS 80) and 

another coastal watershed in Georgetown, SC. The initial 

water table depth of spatially distributed shallow wells, a 

surrogate of soil moisture, is dependent upon rainfall and 

ET, which can be a substantial fraction (as much as 98 

percent) of the annual rainfall (Amatya and Trettin 2010, 

Amatya and others 2009). The annual ROC varied from 

0.34 in the wet year of 2005 with 1527 mm of rainfall to 

as low as just 0.09 for a dry year in 2007 with 994 mm 

of rainfall. The daily average water table was recorded 

as low as 2.39 m in late July-early August of 2006 at the 

well located on well-drained Goldsboro soil. Callahan 

and others (2012) inspected the water table recession 

behavior for Goldsboro, Lenoir, and Rains soils using 

water table hydrograph data. They saw a water table depth 

for Goldsboro of 2.49 m below ground during the extreme 

drought of 2007, and also 2.32 m for the Lenoir soil site 

and 1.8 m for the Rains soil site during the same time 

(see Figure 2). They also estimated water table recession 

coefficients of 0.015, 0.035, and 0.030 day-1, respectively.

Stream flow ceased when the water table dropped below 

50 cm in all wells. There was negligible stream flow 

from late March until November in 2007 as a result of 

dry conditions and high ET demands (Amatya and others 

2009). On the other hand, a very large rain event (172 

mm) on October 25, 2008 brought the water table to 

ponding as much as 17 cm above the surface in one of the 

wells, resulting in an extremely large discharge of 41.6 m3 

s-1 (Conrads and Amatya 2015). 

A close examination of daily rainfall and flow data on 

the watershed showed almost no stream response for 

daily rainfall amounts below 15 mm in the dry summer 

and about 10 mm in the wet winter, respectively, for a 

3-day antecedent dry period for both seasons (Amatya 

and Trettin 2010). Current daily stream gauging data 

indicate that this watershed has no stream flow nearly 

one-third of the time, on average, similar to another 30-

Table 3—Drainage areas and calculated average annual runoff coeffi cients (ROC) for Turkey Creek 

watershed based on map or digital elevation model (DEM) types used during 1964-2011 period 

(after Amatya and others 2013)

Time Map / DEM Type

Delineation 

Method Drainage Area (ha) ROC

1964 1” = 2 mile Topo Manual 3240 0.38

1969 1” = 1 mile Topo Manual 4575 0.27

2004 30 m DEM ArcHydro 4920 0.25

2005 1:24,000 Topo,

10-foot contours Manual 5880 0.21

2008 10 m DEM AV/SWAT 7260 0.17

2010 Partial LiDAR ArcSWAT 6510 0.19

2011 Full LiDAR ArcSWAT 5240 0.24

 LiDAR = light detection and ranging.

ArcHydro = An Extension with a set of data models and tools that operates within ArcGIS to support geospatial and 

temporal data analyses.

AV/SWAT = SWAT (Soil and Water Assessment Tool) Hydrologic Model in ESRI ArcView GIS platform; 

ArcSWAT = SWAT (Soil and Water Assessment Tool) Hydrologic Model in ESRI ArcGIS platform
28 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

km2 forest watershed in coastal North Carolina (Amatya 

and others 2003) but different from the upper coastal plain 

and upland watersheds of similar or smaller size, where 

baseflow is a significant component of streamflow (Bosch 

et al., 2004; Sun and others (2002). This may be due to 

the large surface and subsurface soil water storage and 

high growing-season ET demands typical of the forest 

ecosystems of the low-gradient Coastal Plain, as also 

shown by Sun and others (2002). 

A study of daily stream flow dynamics compared early 

data from the Turkey Creek watershed (WS 78), which 

has some open lands, roads and wetlands, with two 

other adjacent completely forested first- and secondorder watersheds on the Santee Experimental Forest. It 

was hypothesized that somewhat higher annual water 

yields from the larger (WS 78) compared to the smaller 

watershed (WS 80) were due to differences in their land 

use, soils, and topography, as well as increased base flows 

(Amatya and Radecki-Pawlik 2007) and potential errors 

in the drainage area calculated for the flow estimate of 

WS 78, as discussed above (Amatya and others 2013). 

As expected, the pre-Hugo daily flows persisted for 79 

percent of the time with dampened peak flows in the 

larger WS 78 watershed with a larger storage, compared 

to only 65 and 60 percent in the second- and first-order 

watersheds, respectively. The frequency of daily flow 

occurrence on WS 78 dropped to about 68 percent of 

the time for the recent 2005-14 period, possibly because 

of increased ET due to higher temperatures (Dai and 

others 2013) and growing pine stands following Hugo 

(Jayakaran and others 2014). 

Stormflow and Subsurface Flow

In their study using a simple linear baseflow separation 

method, La Torre Torres and others (2011) found baseflow 

contributing up to 56 percent to the total streamflow, with 

an average of about 28 percent. This is consistent with 

Amatya and Trettin (2010), who found similar results 

for recent data using the baseflow separation method by 

Arnold and Allen (1999) for this watershed. Using the 

SWAT model (Arnold and others 1998), Amatya and Jha 

(2011) found that the simulated average annual baseflow 

contributed 24 percent of streamflow. Recent studies that 

used end-member mixing analysis by comparing stream 

flow chemistry to that of precipitation and subsurface 

water have shown that the base flow contribution to 

stream flow is about 40 percent, on average, for the 

upper Turkey Creek system and for the adjacent WS 

80 watershed (Garrett and others 2012, Griffin and 

others 2014). The uncertainty of baseflow separation, 

including by this chemical hydrograph method, is yet 

undetermined, but based on a water table fluctuation 

Figure 2—Daily rainfall and water levels in cm below ground surface for water 

table wells at three locations in the Turkey Creek watershed for the period June 

2006 - December 2008 (from Callahan et al., 2012).
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 29

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

method, the total groundwater recharge for the watershed 

ranged widely from 107 ± 39 mm per year (5-10 percent 

of annual precipitation) for a poorly-drained site (Rains 

soil) to 1140 ± 230 mm per year (62-94 percent of 

annual precipitation) for a moderately well-drained site 

(Goldsboro soil). Analyzing the water budget and range 

of conditions for vertical hydraulic gradients in the 

shallow aquifer, we estimated that the average aquifer 

recharge rate was 114 ± 60 mm per year. Callahan and 

others (2015) highlighted these studies related to storm 

runoff behavior in this coastal plain watershed using 

physical and chemical hydrograph separation techniques. 

Evapotranspiration

Using 13 years (1964-76) of data, Amatya and Trettin 

(2007a) estimated annual ET as a difference between 

precipitation and streamflow. The 13-year mean annual 

ET was 983 mm, and the annual ET remained near the 

potential ET (PET) (>90 percent of average Thornthwaite 

PET of 1079 mm) for the years exceeding the longterm average rainfall and/or the years with just below 

the average but with a wet antecedent year. Years with 

consistently below-average annual rainfall yielded ET 

equivalent to 80 percent or less of the annual PET. This 

mean ET estimate was about 11 percent lower than the 

1107 mm estimated by Richter (1980) for a 12-year 

period (1969-80) on the adjacent WS 77 watershed and 

only 6 lower than the long-term mean reported by Dai 

and others (2013) for the WS 79 watershed. However, 

the temporal and spatial ET dynamics of this watershed 

are still poorly understood. Recently, Amatya and 

others (2014) showed that the forest-based PET can be 

substantially higher than the commonly used grass-based 

PET estimates used in those earlier studies. 

Water Balance

The average annual water balance for this watershed 

using 13 years (1964-1976) of data yielded 1320 mm 

of precipitation with 312 mm of streamflow, using 

recent calculations of watershed area for the old gauge 

downstream of the current USGS gauge. This yielded a 

mean ROC of 0.23 with 95 percent confidence interval 

(CI) of 0.19-0.27 and an average annual ET of 1008 

mm with a 95 percent CI of 932-1084 mm, assuming 

negligible storage and deep seepage. The recent 10 years 

(2005-2014) of data for this forest regenerated since 

Hugo in 1989 yielded mean precipitation of 1306 mm and 

streamflow of only 247 mm, resulting in an ROC of 0.18 

and mean annual ET of 1059 mm. The results indicated 

that although the mean annual post-Hugo flow was 

lower than the pre-Hugo flow, there was no significant 

difference in mean annual ET, potentially indicating the 

return of hydrology to pre-Hugo levels. 

Surface Depressional Storage

Amoah (2008) and Amoah and others (2012) quantified 

representative depressional storage capacity (DSC) of 

six lower coastal plain watersheds, including Turkey 

Creek (WS 78), by implementing a lumped DSC model 

to extract geometric properties of storage elements from 

DEMs of varying grid resolutions (including the LiDARbased DEM) and employing a consistency zone criterion. 

Accordingly, the average DSC was estimated to be 100 

mm for WS 78, in contrast with 93 mm and 10 mm for 

WS 80 and WS 77, respectively, potentially indicating 

some differences in hydrologic responses based on 

wetland size and storage as expressed in DSC.

Riparian Vegetation Effects on Discharge

Riparian vegetation type, composition, structure, and 

abundance on floodplains exert a strong influence on 

riparian surface and subsurface hydrology and discharges 

of rivers and streams, especially in low-gradient 

streams (Benjankar and others 2009, Rood and others 

2005). Miroslaw-Swiatek and Amatya (2011) found a 

close agreement between the modeled stage-discharge 

relationship using a given stream/floodplain cross-section 

with friction parameters controlled by various vegetation 

types and that obtained by the USGS with actual field 

measurements (Conrads and Amatya 2015). In another 

study to evaluate the effects of roughness due to assumed 

shapes of Cypress knees found in the main channel 

and floodplain on Turkey Creek watershed discharge 

calculation, Miroslaw-Swiatek and Amatya (in review) 

showed larger calculated friction factors with reduced 

flow velocities and discharge when a conical knee shape 

was assumed compared to a cylindrical shape. 

Watershed Hydrologic Modeling

A SWAT watershed modeling study conducted by 

Amatya and Jha (2011), extending the initial works 

by Haley (2007) on the watershed, found reliable 

streamflow predictions for the 2005-2010 calibration and 

validation periods. Although the model performance 

was reasonable, further model improvements were 

recommended using more representative LiDARbased DEMs, field parameters, and testing for internal 

consistency for its further ecohydrologic applications. 

Furthermore, since the SWAT model is still unable 

to predict the daily water table dynamics for wetland 

hydrology and its functions and biogeochemical 

processes, efforts are ongoing to develop a simple 

analytical model to simulate daily water table dynamics 

on major soil types using the measured daily precipitation, 

PET, and soil water properties, as described by Amatya 

and others (2015).
30 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Water Quality

Almost no detailed studies on water quality of this 

watershed have been conducted, except for the analysis 

of a 2.5-year (2006-08) data period. This analysis showed 

measured pollutant concentration values within the ranges 

for similar land use of the coastal plain, except for NH4-N, 

which was slightly higher (Amatya and others 2009). 

FUTURE DIRECTIONS AND NEEDS

The long-term studies developed through this 

collaborative research on the Turkey Creek watershed 

provide data necessary as “reference” conditions for 

water resources development and management, wetland 

restoration and conservation, and also for improving 

hydrologic assessment tools needed for management 

decisions on sustaining ecosystem services derived 

from this rapidly urbanizing landscape. However, 

some changes in watershed response are expected with 

time as the forest stands mature and are influenced by 

management practices and potential climate change. As 

this watershed is somewhat isolated from population 

pressure, and development near the coastal waters is 

expected to continue to increase in the southeastern 

United States (Hitchcock and others 2015), we 

recommend the following as topics for future research:

• Monitoring for mercury (Hg) and fecal coliform due to 

large areas of wet soils and wetlands 

• Understanding processes, linkages, and transport 

mechanisms at the freshwater-tidal interface 

• Consideration for monitoring Quinby Creek and others 

adjacent to Turkey Creek for baseline data needed for 

near-future developmental impacts

• Developing research techniques for activities that 

improve forest health and restore ecosystems such 

as thinning, landscape-scale prescribed fire, and 

hydrologic restoration

• Developing an accurate quantification of baseflow and 

storm flow contribution to streamflow

• Developing a quantification of spatial and temporal 

dynamics of evapotranspiration

• Assessing effects of land use and potential climate 

change on hydrology, water quality, and vegetation 

dynamics using validated hydrologic models like SWAT

• Studying watershed responses to wetland and 

stream restoration efforts such as those that might be 

considered in implementing the Revised Francis Marion 

National Forest Plan 

• Studying the carbon dynamics and dissolved organic 

carbon in coastal blackwater streams as a concern for 

water treatment systems and consumer health

Francis Marion National Forest is in the process of 

revising the Forest Management Plan (US Forest Service 

2015). Turkey Creek is identified as one of the priority 

watersheds for 1) improving hydrologic functions and 

watershed health based on past modifications as well as 

the rehabilitation of existing cross-drainage structures that 

affect wetland and riparian structure, biota, processes, 

and functions and 2) restoring longleaf pine ecosystem 

together with red-cockaded woodpecker (Picoides 

borealis) habitat as an at-risk species (Maceyka and 

Hansen 2015; Danaher 2015). Accordingly, opportunities 

may exist in the future for collaborative studies to address 

relevant issues on this watershed. 

ACKNOWLEDGMENTS

The supporters and collaborators in this study include: the 

U.S. Department of Agriculture Forest Service, Southern 

Research Station for continued funding support; National 

Council of Air and Stream Improvement (NCASI), Inc. 

for funding used as a cost-share support at the initiation 

of TCWRI revitalization in late 2004; the College of 

Charleston and U.S. Geological Survey, South Carolina, 

for installation, continued servicing, and data collection 

at the Turkey Creek stream gauging station; South 

Carolina Department of Transportation for giving access 

for installation of the gauging station on its new bridge 

on SC Highway 41 N; Tetra-Tech, Inc., Atlanta, Georgia 

as a cooperator in Turkey Creek historic streamflow 

data digitizing and sharing; Francis Marion National 

Forest, SC for funding installation of four groundwater 

well recorders/dataloggers in 2006 and other continued 

watershed information support; Forest Service Southern 

Research Station Civil Rights Committee for students’ 

support at Florida A&M University in the summer of 

2005 and 2006 and also at Gainesville State College (GA) 

in summers of 2010 and 2011; South Carolina Sea Grant 

Program for providing funding support for College of 

Charleston-sponsored graduate student studies from 2006 

to 2008; Forest Service National Groundwater Monitoring 

Program for funding of a pilot field monitoring training 

for Level I and II of the Groundwater Dependent 

Ecosystem Inventory program in 2010; U.S. Fulbright 

Fellowship Program for awarding a fellowship to Dr. 

Devendra Amatya to conduct collaborative research 

with faculty at Agricultural University of Krakow and 

Warsaw University of Life Sciences in Poland in 2010-

11; Overseas Economic Cooperation and Development 

(OECD) for awarding travel supports to Dr. Artur 

Radecki-Pawlik in 2004 and Dr. Dorota MiroslawSwiatek in 2010 for conducting studies on the watershed; 

and College of Charleston for hosting part of the housing 

during the research scholar’s visits. The authors also 

acknowledge the U.S. Vegetable Laboratory, College 

of Charleston, and Clemson University for providing 

meeting rooms for the watershed cooperators’ meetings 

in 2007, 2011 and 2013, respectively. Thanks are also 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 31

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

due to former PhD student Joseph Amoah (Florida A&M 

University); former MS students Elizabeth Haley, Ileana 

La Torre Torres, Guinn Garrett, and Michael Griffin; and 

current MS student Austin Morrison from College of 

Charleston for conducting research on this watershed. 

The authors also express their thanks to Dr. Thomas 

M. Williams, Professor Emeritus, Clemson University, 

SC and Mr. William F. (Bill) Hansen, Professional 

Hydrologist, Lexington, SC for their help with review of 

this paper with constructive suggestions to enhance its 

quality. Finally, the authors acknowledge the assistance 

from two employees of the Forest Service Center for 

Forested Wetlands Research: Andy Harrison, Hydrologic 

Technician, for installation, service, and maintenance of 

monitoring stations and their data management; and Julie 

Arnold, Biological Technician, for preparing the updated 

Geographic Information System-based location map 

shown in Figure 1.

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34 Headwaters to Estuaries: Advances in Watershed Science and Management

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Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

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DECIPHERING STORM-EVENT RUNOFF BEHAVIOR IN A 

COASTAL PLAIN WATERSHED USING CHEMICAL AND PHYSICAL 

HYDROGRAPH SEPARATION TECHNIQUES

Timothy Callahan, Austin E. Morrison1

Interpreting storm-event runoff in coastal plain watersheds is challenging because of the 

space- and time-variable nature of different sources that contribute to stream flow. These 

flow vectors and the magnitude of water flux is dependent on the pre-storm soil moisture (as 

estimated from depth to water table) in the lower coastal plain (LCP) region. For example, 

sites with typically sandy, well-drained soils can exhibit runoff behavior similar to sites 

with low-permeability, poorly-drained soils if the pre-storm water table position is close to 

the surface. Interpreting source contributions to storm runoff include physical (hydrograph 

separation) and chemical (end member mixing analysis [EMMA]) methods, among others. 

Our main objective was to reduce uncertainty in calculations of stream flow contribution 

following storm events by analyzing the water isotope signatures of prospective sources to 

stream flow. Ratios of the stable isotopes of water (18/16 oxygen, and deuterium/hydrogen) 

were measured for the different prospective contributing sources and in stream water for 

storm events; EMMA was performed to characterize the percentage contributions of sources 

to stream flow. This was compared to physical hydrograph separation techniques that separate 

quickflow and baseflow components of stream flow response to storms. Chemical and 

physical hydrograph separation methods can show storm-specific discrepancies raising the 

question of which method correctly identifies the relative contributions of different sources 

such as groundwater, soil water, and overland flow to stream flow. The study sites were in the 

lower Atlantic coastal plain of the Southeast U.S., from the headwaters to the downstream 

US Geological Survey stream gage (ID 02172035) at Turkey Creek above Huger, South 

Carolina. The Turkey Creek watershed is a 5,240-hectare, third-order system in the Francis 

Marion National Forest in Berkeley County and has a confluence with Nicholson Creek, 

forming Huger Creek which drains to the East Branch of the Cooper River and ultimately to 

Charleston Harbor. This forested, wetland-rich watershed is an important reference system for 

the rapidly-developing Charleston metropolitan area and is of interest to watershed managers 

and stakeholders wishing to understand the hydrological processes influencing storm water 

dynamics. Our results will illustrate the complexity of runoff production dynamics in LCP 

watersheds and show that using multiple methods provides a more nuanced understanding 

of hydrological processes. We will also show that a hydrogeochemical approach to 

understanding processes on the LCP watersheds is not cost- or time-prohibitive, and can 

provide critical information to land managers and policymakers who oversee the urbanization 

of these watersheds.

1

Timothy Callahan, Geology Associate Professor, College of Charleston, Charleston, SC 29424

Austin E. Morrison, Graduate Program in Environmental Studies, College of Charleston, Charleston, SC 29424
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 35

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

DEFINING ECOHYDROLOGICAL FUNCTION TO SUPPORT LOW IMPACT 

DEVELOPMENT IN COASTAL SOUTH CAROLINA

Daniel Hitchcock, A.D. Jayakaran, T. H. Epps, 

J. A. Palazzolo, T. M. Williams, D. M. Amatya1

In the face of dual pressures in coastal South Carolina - residential and commercial 

development, along with potential climate change impacts - stakeholders need clear, accurate, 

relevant, and easily-accessible information for effective decision-making for watershed 

management and natural resource protection. To fill this need, we focus on defining 

ecohydrological criteria for sustainable land and water resource guidance, specifically in 

upland areas that ultimately drain to tidal creeks. Runoff coefficients and derived curve 

numbers (CNs) – hydrologic metrics that define rainfall-runoff relationships based on 

watershed and landscape characteristics - have been calculated for first-order watersheds 

that have low gradient topography and shallow groundwater. Results have implications for 

watershed planning and site engineering, including storm water management and design. 

Forested water budgets, including the seasonal influence of evapotranspiration and infiltration 

on water table elevation as it drives highly variable streamflow, are being refined with the goal 

of defining pre-development conditions. These results have the potential to not only inform 

coastal stormwater discharge target criteria, but also to guide the prioritization of conservation 

and restoration efforts. Stormwater control measures, specifically engineered wetlands 

and bioretention systems, are being investigated to determine hydraulic and water quality 

performance considering influence of shallow groundwater. Results will be integrated into an 

online mapping tool so that site-specific geospatial data -based information can be available to 

decision-makers. An assessment of existing resources (green infrastructure) and their benefits 

- via ecosystem services at various scales - can provide guidance toward resource protection 

with the goal of creating resilient communities - whether by conservation or restoration 

efforts, or by better site design during land use change.

1

Daniel Hitchcock, Associate Professor, Ecological Systems, Clemson - Baruch Institute, Georgetown, SC 29585

A.D. Jayakaran, Associate Professor, Washington State University, Puyallup, WA 98371

T.H. Epps, Student, Clemson - Baruch Institute, Georgetown, SC 29585

J.A. Palazzolo, Student, Clemson - Baruch Institute, Georgetown, SC 29585

Devendra Amatya, Research Hydrologist, USDA Forest Service, Center for Forested Wetlands Research, Cordesville, SC 29434
36 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ENHANCING HYDROLOGIC MAPPING USING LIDAR AND HIGH 

RESOLUTION AERIAL PHOTOS ON THE FRANCIS MARION NATIONAL 

FOREST IN COASTAL SOUTH CAROLINA

Andy Maceyka and William F. Hansen1

Abstract—Evaluating hydrology within coastal marine terrace features has always been problematic as watershed 

boundaries and stream detail are difficult to determine in low gradient terrain with dense bottomland forests. Various 

studies have improved hydrologic detail using USGS Topographic Contour Maps (Hansen 2001, Eidson and others 

2005) or Light Detection and Ranging (LIDAR) in gullied piedmont terrain (James and others 2007), and the Maryland 

coastal plain (Lang and others 2012). Research within Turkey Creek subwatershed near Huger, SC used LIDAR and field 

verification to estimate the size of the 52.4 km2 subwatershed, but the 50-year history had estimates ranging from 32.4 to 

72.6 km2 (Amatya and others 2013). 

Turkey Creek was one of 21 subwatersheds evaluated 

using LIDAR intended for the Plan Revision covering 

the 1,050 km2 Francis Marion National Forest (FMNF). 

LIDAR has proven to be a valuable asset to forest 

planning by more accurately defining or locating 

many things including stream networks and watershed 

boundaries. LIDAR data used to map Turkey Creek were 

attained in February and March of 2009. Streamflow in 

Turkey Creek was primarily 0.05-0.28 m3s-1 (somewhat 

below the 9-year average of 0.39 m3s-1) so most perennial 

and intermittent streams should contain water, but small 

streams and seeps are unlikely to be noticed. Highresolution ortho imagery (ESRI’s World Imagery, NAIP 

2013 imagery) was also helpful for image interpretation. 

The mapping procedure employed both “heads-up 

digitizing” and DEM-based modeling. It was an iterative 

process of digitizing and remodeling. Hydrologic barriers 

were removed from the LIDAR-derived DEM so flow 

could be modeled. This was accomplished by first, hand 

digitizing streams that were clearly visible by proxy, 

based mostly on the linear nature of missing LIDAR 

ground returns due to the absorption of laser pulses by 

water. In flat, wet landscapes this valuable information 

is often lost using current methods to model ground 

surfaces. LIDAR-derived DEMs can “washout” stream 

channels in areas due to low topographic relief and/or 

too few laser returns to properly define ground versus 

low vegetation or noise returns. The “washout” effect 

is a result of the alogrithm selecting available stream 

bank or low vegetation laser returns in areas with no 

other laser returns (i.e. water). Errors in ground surface 

are especially problematic in wet areas with low, dense 

vegetation. When this “washout” occurs it can be difficult 

to model stream networks using current DEM-based 

modeling alone. When using current DEM-based methods 

in these challenging areas, a substantial amount of work 

is needed to provide a relatively clear path to model 

streams. Without a “cleared” and defined hydrologic path, 

the flow accumulation models often get diverted and 

loose channel contact. Stream paths are “cleared” using 

digitized line work to keep stream in its main channel. 

Areas of channel uncertainty, the laser point cloud in 

planimetric or vertical profile reveals areas with no returns 

and streams can be recognized if they contain water. 

Although not as prolific, these flow modeling issues also 

occur in the piedmont and mountains, and have to be 

recognized and dealt with. After digitizing the streams 

and ditches based on recognizable channels or continuous 

water bearing features, the stream lines were burned into 

a DEM and remodeled. The flow modeling tools identify 

only one channel, and the analyst needs to keep it in the 

main channel. Weighing the imagery and LIDAR derived 

evidence considering DEM statistics set to refresh with 

the current display extent (scale), using descrete colors to 

separate elevation detail and lack of returns from water 

absorbing the LIDAR pulses are all needed to digitize a 

refined channel location before burning in the primary 

channel network. Recognizing characteristic landforms 

with braided, meandering to linear (ditched) channels 

1

Andy Maceyka, Francis Marion & Sumter National Forest GIS Specialist and Southern Region (R8) Remote Sensing Technician, USDA Forest 

Service, Francis Marion and Sumter National Forest, Columbia, SC 29212 

William Hansen, Professional Hydrologist (retired USDA Forest Service Hydrologist) - Hansen Hydrology, owner/operator, Lexington, SC 29072
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 37

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

and their associated hydrology are helpful in making 

assumptions and interpretations. 

Amatya and others (2013) describe improvements in the 

Turkey Creek boundary as more detail was acquired. 

This landscape analysis needs work, review, and some 

field verification. The flow modeling applied the median 

drainage size for North Carolina (NC) Coastal Flatwoods 

perennial or intermittent streams was about 16 ha 

(Russell and others 2008, Russell 2013). The 2005 WBD 

boundaries used 10-foot contour USGS Topographic 

Maps and aerial photos to remotely evaluate hydrologic 

details. Improvements in the National Hydrography 

(NHD) and Watershed Boundary Datasets (WBD) will 

undergo more formal review before updating. However, 

substantial refinement can be made by applying LIDAR 

detail in georeferencing streams, hydrologic boundaries 

and identifying modifications (e.g., ditches, dikes). 

There are also instances where vegetation is so dense 

(e.g., pocosins, Carolina bays) that the laser pulse cannot 

penetrate to water, channel or ground surface and the 

DEM surface appears elevated. Channel margins with 

atypical roughness are possible signs of spoil materials 

from past channelization. Signs of silvicultural bedding, 

rutting, and wetland drainage are also noticable. 

Understanding the channel morphology, past activity and 

vegetation detail helps with interpretation. The extent and 

separation among perennial, intermittent and ephemeral 

streams is not well defined in gathering LIDAR data from 

one flight. However, as more LIDAR flights occur during 

wet and dry seasons, the successive extent of water could 

be related to the Turkey Creek flow duration curve and 

stream permanance separation may improve. Intermittent 

streams are estimated based on NC information (Russell 

2013) using the median16 ha flow accumulation and then 

removing modeled streams from landscape depressions. 

However, data collected about flow permanance in 

the NC coastal plain are variable on drainage size, 

with 80 percent of ephemeral to intermittent streams 

ranging from 1.3 to 127 ha, and ephemeral to perennial 

from 0.1 to 72 ha. With variability likely, median data 

on NC stream permanence may produce reasonable 

landscape estimates, but for individual streams, errors 

of omission and commission are likely without field 

verification. Differences in estimated watershed size of 21 

subwatersheds indicate a standard deviation of 10 percent, 

while modeled/digitized streams within the FMNF 

increased stream density averaging 179 percent (Table 1). 

Figure 1 presents preliminary differences between 

existing and modeled/digitized streams and boundaries for 

Turkey Creek subwatershed. Refined coastal watershed 

boundaries and drainage network may reduce planning 

errors and improve regulatory, design, mitigation and 

restoration decisions. 

Figure 1—Preliminary boundary and stream changes for Turkey Creek, Francis 

Marion National Forest, Berkeley County, SC.
38 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Subwatershed 

(6th Level HUC) 

(% NF)

WBD_GIS 

(km2

)

Modeled 

Boundary 

GIS 

(km2

)

Gain/Loss 

(km2)

Estimated 

Boundary 

Based 

Change 

percentage

NHD NF 

Stream 

density 

(km/km2

)

Modeled 

NF Stream 

density 

(km/km2

)

Modeled 

NF stream 

increase 

over NHD 

(percent)

Awendaw Creek (83%) 103.9 119.6 15.6 15.1% 0.43 2.06 377%

Cane Pond Branch (79%) 43.5 52.3 8.8 20.3% 0.77 2.32 203%

Copahee Sound (0.7%) 127.3 128.5 1.2 1.0% 1.12 4.26 280%

East Branch Cooper River (8%) 75.8 84.4 8.6 11.4% 1.35 2.68 98%

Echaw Creek (72%) 114.9 124.7 9.8 8.5% 0.43 2.05 373%

French Quarter Creek (27%) 78.3 73.3 -5.0 -6.4% 0.71 2.14 202%

Gough Creek (49%) 50.4 46.5 -3.9 -7.7% 1.53 2.79 82%

Guerin Creek (44%) 161.9 157.8 -4.2 -2.6% 0.93 2.52 170%

Headwaters Wambaw Creek 

(93%) 87.1 80.3 -6.8 -7.8% 0.44 2.01 362%

Lower Wando River (1%) 130.9 135.1 4.2 3.2% 0.05 0.49 920%

Nicholson Creek (96%) 118.3 97.2 -21.2 -17.9% 0.89 1.98 122%

Outlet Wambaw Creek (79%) 99.5 121.1 21.7 21.8% 1.35 2.44 82%

Quinby Creek (62%) 91.8 91.8 -0.0 -0.0% 1.14 2.38 108%

Table 1—Francis Marion National Forest - Estimated Change in Watershed Size and Stream Density

Preliminary comparison of existing watershed boundary data (WBD) and hydrologic modeled boundary data with refi ned streams. 

Preliminary comparison of existing national hydrography data (NHD) and hydrologic modeled and edited streams within the national 

forest (NF) areas only. 

NHD stream extent on NF lands was 750 km, modeled and edited streams was 2092 km, an average increase of 179%.

Subwatersheds with low ownership have had less work and subject to higher error.

Dutart Creek - Savanna River subwatershed had insuffi cient LIDAR data available and was not evaluated.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 39

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

LITERATURE CITED

Amatya, D.M.; Trettin, C.; Panda, S.; Ssegane, H. 2013. Application 

of LiDAR data for Hydrologic Assessments of Low-gradient 

Coastal Watershed Drainage Characteristics. Journal of Geographic 

Information System. 5(2): 30251.

Eidson, J.P.; Lacy, C.M.; Nance, L.; Hansen, W.F.; Lowery, M.A.; 

Hurley, N.M. Jr. 2005. Development of a 10- and 12-digit hydrologic 

unit code numbering system for South Carolina, 2005: U.S. 

Department of Agriculture, Natural Resources Conservation Service, 

38 p. + 1 pl.

ESRI’s World Imagery; Esri, DigitalGlobe, GeoEye, Earthstar 

Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping, 

Aerogrid, IGN, IGP, swisstopo, and the GIS User Community

Hansen, W.F. 2001. Identifying stream types and management 

implications. Forest Ecology and Management. 143(1-3): 39-46.

James, L.A.; Watson, G.D.; Hansen, W.F. 2007. Using LiDAR data 

to map gullies and headwater streams under forest canopy: South 

Carolina, USA. Catena. 71(1): 132-144. 

Lang, M; McDonough, O.; McCarty G., Oesterling, R.; Wilen, B. 2012. 

Enhanced detection of wetland-stream connectivity using LiDAR. 

Wetlands. 32: 461-473.

NAIP 2013 imagery. USDA-FSA Aerial Photography Field Office

National Hydrography (NHD) and Watershed Boundary Datasets 

(WBD). U.S. Environmental Protection Agency (USEPA) and the 

U.S. Geological Survey (USGS) in collaboration with other Federal 

and State Agencies.

Russell, P. 2008. Mapping headwater streams: intermittent and perennial 

headwater stream model. NC Division of Water Quality, Final Report 

for Federal Highway Administration. WBS: 36486.4.2. January 28, 

2008. 54 p.

Russell, P. 2013. The extent of streams in North Carolina flatwoods 

based on drainage size. Sampling results from NC DENR. Updated 

results on NC coastal flatwoods provided from P. Russell to W.F. 

Hansen, February, 2013 based on 2008 methods. 
40 Headwaters to Estuaries: Advances in Watershed Science and Management

Multicollabortive Research on Turkey Creek Watershed and Beyond: 10-Year Accomplishments and New Directions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

FRANCIS MARION NATIONAL FOREST FOREST PLAN 

REVISION-ECOSYSTEMS & RESTORATION NEEDS

Mark Danaher1

The Forest Service is currently revising the previous 1995 Forest Plan for the Francis 

Marion National Forest in Coastal South Carolina developed in the wake of Hurricane 

Hugo which devastated the forest in 1989. Since 1995, the human communities surrounding 

the Francis Marion National Forest have grown and changed significantly. The revised 

Francis Marion Forest Plan is being developed under the 2012 Forest Planning Rule. More 

information concerning the Francis Marion National Forest Plan Revision can be found at: 

http://www.fs.usda.gov/main/scnfs/landmanagement/planning. 

The 2012 Forest Planning Rule adopts a complementary coarse filter “ecosystem” and 

fine-filter “species” approach to ensure the long-term persistence of native species. The 

coarse-filter, “ecosystem” approach assures biological diversity. “Ecosystem” forest plan 

components provide direction to maintain conditions needed for most plant and animal 

species. As needed, fine-filter “species” direction contributes to the recovery of threatened 

and endangered species, conserves proposed and candidate species, and maintains a viable 

population of each species of conservation concern– all collectively referred to as: “At Risk 

Species”. The Forest Plan addresses desired conditions on a forest-wide scale (that is, the 

desired conditions are applicable across the landscape of the Francis Marion National Forest). 

Many of the desired conditions are ecosystem based and integrate resource management 

objectives and resource values. However, where appropriate, conditions are described in 

relation to specific geographic areas to allow focus on unique or localized circumstances. 

This presentation will discuss how the 26 subwatersheds (6th level Hydrological Unit Code) 

on the Francis Marion National Forest will be addressed, along with how they correlate with 

the coarse and fine filter approaches. Currently, three sub-watersheds including Turkey Creek 

have been identified as a priority for restoration on the Francis Marion National Forest.

1

Wildlife Biologist, USDA Forest Service, Huger, SC 29467
New Insights into Studies on Long-term 

Experimental Watersheds to Address 

Contemporary Emerging Issues 

(PART 1)
42 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE LONG TERM AGROECOSYSTEM RESEARCH NETWORK – 

SHARED RESEARCH STRATEGY 

Jean L. Steiner, Timothy Strickland, Peter J.A. Kleinman, Kris 

Havstad, Thomas B. Moorman, M. Susan Moran, Phil Heilman, 

Ray B. Bryant, David Huggins, and Greg McCarty1

Abstract—While current weather patterns and rapidly accelerated changes in technology often focus attention on 

short-term trends in agriculture, the fundamental demands on modern agriculture to meet society food, feed, fuel and 

fiber production while providing the foundation for a healthy environment requires long-term perspective. The LongTerm Agroecoystem Research Network was established by USDA to ensure sustained crop and livestock production 

and ecosystem services from agriculture, as well as to forecast and verify the effects of environmental trends, public 

policies, and emerging technologies. The LTAR Network is comprised of 18 locations across the US, whose shared 

research strategy is to employ common measurements to advance four areas of foundational science: (1) agro-ecosystem 

productivity; (2) climate variability and change; (3) conservation and environmental quality; and (4) socio-economic 

viability and opportunities. Each Network location is engaged in a local adaptation of the “common experiment” which 

contrasts conventional production systems with innovative systems that optimize services. Protocols and services are being 

developed for collection, verification, organization, archives, access, and distribution of data associated with Network 

activities. 

INTRODUCTION

Challenges to agriculture have never been greater. The 

American Society of Agronomy’s Grand Challenge for 

the 21st Century (ASA 2011) is “to double global food, 

feed, fiber, and fuel production on existing farmland 

... with production systems that enable food security; 

use resources more efficiently; enhance soil, water, and 

air quality, biodiversity, and ecosystem health; and are 

economically viable and socially responsible.” Long-term 

research is essential to understanding how agriculture 

has and will adapt to changes in technologies, consumer 

demands (food, fuel, fiber and other ecosystem services), 

policy, resource availability and environmental stresses 

(Walbridge and Shafer 2011). Existing networks, such as 

the National Ecological Observatory Network (NEON), 

Long-Term Ecological Research (LTER) network and 

Smart Forest initiative (U.S. Forest Service) reflect the 

established recognition of the need for coordination and 

consistency in land management research programs. 

Agriculture faces tremendous challenges in meeting 

multiple, diverse societal goals, including a safe and 

plentiful food supply, climate change adaptation/

mitigation, supplying sources of bioenergy, improving 

water/air/soil quality, and maintaining biodiversity. The 

Long Term Agroecosystem Research network (LTAR) was 

developed in 2012 to enable long-term, trans-disciplinary 

science across farm resource regions to address these 

challenges (Walbridge and Shafer 2011). The goal of 

this research network is to ensure sustained crop and 

livestock production and ecosystem services from 

agro-ecosystems, and to forecast and verify the effects 

of environmental trends, public policies, and emerging 

technologies. The LTAR shared research strategy (SRS) 

is a living document, founded on the basic goals of the 

LTAR Network and designed to capitalize on the strengths 

of the 18 LTAR sites. The LTAR SRS creates common 

geographically- and temporally-scalable databases 

that deliver knowledge and applications within priority 

areas of concern: agro-ecosystem productivity; climate 

1

Jean Steiner, Soil Scientist, USDA Agricultural Research Service, El Reno, OK 73036

Timothy Strickland, Soil Scientist, USDA Agricultural Research Service, Tifton, GA 37194 

Peter Kleinman, Hydrologist, USDA Agricultural Research Service, University Park, PA 16802 

Kris Havstad, Range Scientist, USDA Agricultural Research Service, Las Cruses, NM 88003 

Thomas Moorman, Microbiologist, USDA Agricultural Research Service, Ames, IA 50011 

M. Susan Moran, Hydrologist, USDA Agricultural Research Service, Tucson, AZ 85719 

Phil Heilman, Hydrologist, USDA Agricultural Research Service, Tucson, AZ 85719 

Ray Bryant, Soil Scientist, USDA Agricultural Research Service, University Park, PA 16802 

David Huggins, Soil Scientist, USDA Agricultural Research Service, Pullman, WA 99164

Greg McCarty, Soil Scientist, USDA Agricultural Research Service, Beltsville, MD 20705
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 43

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

variability and change; conservation and environmental 

quality; and socio-economic viability and opportunities.

SITES

There are eighteen sites representing major 

agroecoregions of the US in the LTAR network, and 

flexibility to add additional sites to fill in critical gaps. 

The first 10 sites were selected in 2012, all from longterm watershed, rangeland, or cropping system locations 

within the Agricultural Research Service (ARS). In 2014, 

eight additional sites were selected; some led by ARS, 

universities and private research foundation. During both 

selection cycles, sites were evaluated on representation of 

a major agroecosystem, a history of long-term research 

and existence of historic data, demonstration of critical 

mass with strong collaborative partnerships, and a record 

of scientific leadership and productivity as a team. The 

diversity of sites is summarized briefly in Table 1. 

PROCEDURES

Research Committee

The Shared Research Strategy and implementation for 

elements within that strategy have been developed and 

coordinated through the LTAR Research Committee, 

consisting of a chair from ARS’s Office of National 

Programs and the site leads. Site leaders engage 

members of their site teams, as needed, to advance 

LTAR planning and implementation. The work of the 

Research Committee has been conducted through monthly 

teleconferences, working groups, and annual meetings. 

Working Groups

Following initial teleconference discussions, the Research 

Committee established a writing team to draft the SRS. 

The writing team developed a draft and engaged the 

broader LTAR community, ARS leadership, and an 

external review panel for feedback and refinement. The 

first edition of the LTAR-SRS was posted to the LTAR 

website (Bryant et al. 2013). After addition of 8 sites 

to the network, another working group was established 

to update the SRS which is in final review by ARS 

leadership. 

As the work of the SRS writing team progressed 

additional teams were established to develop a research 

plan for a Common Experiment. The LTAR Core 

Measurements and shared protocols are being developed 

by working groups with expertise in the various areas 

essential to LTAR research efforts. Additionally, teams 

are compiling historical data from multiple locations 

for analysis of precipitation intensity and biomass 

productivity. 

Annual Meetings 

Periodic face-to-face meetings have been essential 

toward building shared understanding across the LTAR 

network. The first LTAR Annual Meeting was held in 

conjunction with the 2012 LTER All-Scientists Meeting 

in Estes Park, Colorado, and the subsequent joint LTAR/

NEON workshop at NEON HQ in Boulder, Colorado. 

Discussions at these meeting focused on the SRS and 

Core measurements. The next Annual Meeting was 

retreat style, held at the Central Plains Experimental 

Range in Nunn, Colorado. A key output of that meeting 

was development of the concept and basic outline of 

a Common Experiment that would be implemented 

at all sites. The team met again in conjunction at the 

2014 American Geophysical Union fall meeting where 

a Union Session was presented on The Long-Term 

Agro-Ecosystem (LTAR) Network: A New In-Situ Data 

Network for Agriculture. The LTAR Research Committee 

met and determined the need for a LTAR Team planning 

meeting, focused on the LTAR Core Measurements and 

Shared Protocols, which has been scheduled in Beltsville, 

Maryland in spring of 2015. 

DISCUSSION

The LTAR’s SRS is built upon a progressive approach 

that (1) focuses on priority research questions, 

(2) reviews measurement variables and protocols used 

by sites to confirm comparability and identify a core 

set of variables and protocols for the network to adopt, 

(3) develops shared data sets from across network 

sites, (4) initiates new monitoring and experimentation 

efforts in conjunction with other networks, and 

(5) conducts retrospective analyses of trends across 

LTAR sites and modeling studies to generalize locallyderived observations and forecast future outcomes. 

Successful implementation of LTAR’s SRS is based 

on the commitment to the SRS across all network 

sites, energetic leadership from each participant in the 

network, and the engagement of producers, partners and 

policymakers. The LTAR research is being structured 

to address four societal concerns: 1) Agroecosystem 

productivity and sustainability; 2) Climate variability and 

change; 3) Conservation and environmental quality; and 

4) Socio-economic viability and opportunities. 

LTAR’s Shared Research Principles

Foundational science addresses the key societal concerns 

through research questions that are targeted toward 

development of improved understanding, tools, and 

products that enhance productivity and sustainability of 

agricultural systems (Fig. 1, Table 2). A key expectation 

of the LTAR Network is the application of research 

results to solve critical challenges facing agriculture. 

Because research based applications and their outcomes 
44 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

LTAR Site and Location

EstablishedRecord

(years†)

Area 

(km2) Network Affi liations‡

Major crops, land use, and 

livestock production

R.J. Cook Agronomy Farm, 

Pullman, WA

1999 14 0.57 LTAP, GRACEnet, 

REAP, NADP

Wheat, barley, pulses (peas, 

lentils, chickpeas)

Central Plains Experimental 

Range, Cheyenne, WY; 

Nunn, CO

1939 75 865 LTER, NEON, 

GRACEnet, NADP

Wheat-fallow, rangeland, beef 

cattle

Gulf Atlantic Coastal Plain, 

Tifton, Georgia; (Little River 

Experimental Watershed)

1965 46 334 CEAP, GRACEnet, 

NADP

Cotton, peanuts, corn, 

vegetables (~50% irrigated); 

poultry, beef cattle 

Central Mississippi River Basin, 

Columbia, MO

1971 43 480 CEAP Grain cropping systems, some 

pasture, riparian forest

Jornada Experimental Range, 

Las Cruces, NM

1912 100+ 780 CEAP, LTER, NEON, 

WNBR, UV-B MRP, 

USCRN, COSMOS

Rangeland, beef cattle, wildlife

Northern Plains, 

Mandan, ND

1912 100+ 9.7 NEON, CEAP, 

GRACEnet, REAP

Small grains, row crops, beef 

cattle on grazingland

Southern Plains, 

El Reno, OK

1948, 

1961

53 1,423 CEAP, COSMOS Beef cattle, winter wheat, 

pasture, forages, prairie

Upper Chesapeake Bay, 

University Park, PA 

1968 46 1,127 CEAP, GRACEnet Row crops, dairy, pasture, forest

Upper Mississippi River Basin, 

Ames, IA

1992 22 6,200 AmeriFlux, CEAP, 

GRACEnet

Corn-soybean with livestock 

(swine, beef, dairy)

Walnut Gulch Experimental 

Watershed, Tucson, AZ

1953 61 150 Amerifl ux, CEAP, 

COSMOS, EOS

Rangeland, beef cattle, wildlife

Lower Chesapeake Bay,

Beltsville, MD

1910 21 27 CASTnet, CEAP, 

COSMOS, EOS, 

NADP, GRACEnet, 

SCAN, UV-B MRP

Cropland, poultry, dairy, forages, 

pasture, horticulture 

Archbold Biological Station/

University of Florida, Venus, FL/

Ona, FL

1941 73 102 AmeriFlux, GLEON, 

NutNet, USCRN

Beef cattle, pasture, rangeland, 

wildlife

Eastern Corn-Belt, 

Columbus, OH

1974 Up to 40 N/A CEAP, GRACEnet, Cropland, swine, dairy poultry

Great Basin Floristic Province 

Boise, ID

1961 53 239 CEAP, CZO, NADP, 

SCAN

Rangeland, beef cattle, wildlife

Kellogg Biological Station Hickory 

Corners, MI

1987 26 0.42 LTER Cropland

Lower Mississippi River Basin, 

Oxford, MS

1981 34 21.3 COSMOS, CEAP, 

SURFARD, SCAN, 

Cotton, corn, soybeans, rice, 

catfi sh, sugar cane.

Platte R./High Plains Aquifer, 

Lincoln, NE

1912 100+ 16500 AmeriFlux, 

GRACEnet, REAP,

Cropland, rangeland, beef 

cattle, biofuels

Texas Gulf

Temple, TX

1937 75 N/A CEAP, EPA-STN, 

GRACEnet, NutNet, 

LTBE, SCAN

Cropland, rangeland, pasture, 

remnant prairie

† Through 2014

‡ CASTnet: Clean Air Status and Trends Network; CEAP: Conservation Effects Assessment Project; COSMOS: COsmic-ray Soil Moisture 

Observing System; CZO: Critical Zone Observatory; EOS: Earth Observation System; EPA-STN: USEPA Speciation Trends Network; 

GLEON: Global Lake Ecological Observatory Network; GRACEnet: Greenhouse gas Reduction through Agricultural Carbon Enhancement 

Network; LTAP: Long Term Agro-Ecological Pilot; LTBE: Long-Term Biomass Experiment; LTER: Long Term Ecological Research; NADP: 

National Atmospheric Deposition Program; NEON: National Ecological Observatory Network; NutNet: Nutrient Networt; REAP: Renewable 

Energy Assessment Project; SCAN: Soil Climate Analysis Network (all sites); SURFARD: NOAA Surface Radiation Network; UV-B MRP: 

UV-B Monitoring and Research Program; USCRN: US Climate Reference Network; WNBR: World Network of Biosphere Reserves.

Table 1—Characteristics of the 18 LTAR Network sites selected in 2012 or 2014. 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 45

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

are impacted by continually-changing trends, demands, 

and innovations, the LTAR SRS exploits a mixture of 

data from on-going networked science, new cross-site 

experiments, and long-term historical measurements. 

The ongoing integration of foundational science with 

long-term, multi-location experimental data underpins 

the provision of four key LTAR products: new knowledge 

of processes and systems, new technologies and 

management practices, improved agroecological models, 

and comprehensive, accessible data. 

The LTAR network will provide regional test-beds where 

the long-term outcomes of agricultural germplasm, 

technologies, agrochemicals, management strategies, 

and policies to increase sustainable production systems 

and environmental protection will be evaluated via 

retrospective (i.e., historical) and prospective (i.e. 

predictive) research projects. The research will be 

conducted across a range of spatial and temporal scales in 

order to better understand the processes that result in field 

to landscape scale outcomes (Fig. 2). These results will be 

accomplished via a hierarchical research strategy (Figure 

3) built upon foundation science in four topical areas that 

yields four key product categories supporting four major 

outcome areas for US agriculture. This process outline in 

Figure 1 and Table 2 is driven by societal concerns related 

to food supply, climate change adaptation/mitigation, 

bioenergy, water/air/soil quality, biodiversity, and 

economic sustainability and livelihoods. The foundation 

science of the LTAR network will be directed toward 

knowledge gaps and technology needs under four topical 

areas. 

Core Measurements

The shared LTAR research questions will require a set 

of cross-site measurements related to studies of key 

agroecosystem processes. Table 3 lists measurements 

that support the foundation science of the SRS. This list 

will evolve as measurement technologies improve and 

additional parameters are identified. Recent trends in 

ecosystem measurements are to deploy in-situ real-time 

sensor networks. The LTAR sites will seek opportunities 

to create networks using common equipment and 

measurement methodologies to facilitate cross-location 

comparisons.

Shared Protocols

Efforts toward common methods and data protocols will 

be driven by 1) the cross-site datasets that are most easily 

compared and shared; 2) the datasets most needed for 

ongoing cross-site research projects; 3) new long-term 

datasets that can be compiled for all sites; 4) the common 

instrumentation/protocols already in place; and 5) critical 

new instrumentation and/or measurements, where 

examples of each are given in Appendix E.

LTAR sites will work to adopt common protocols from 

the LTAR methods “catalog” as new measurements are 

added and as old equipment is replaced. In some cases, 

it will be expedient to initiate new cross-site research 

at a few select sites, and then validate or expand results 

to a larger number of sites. An example is constructing 

a nutrient budget at sites with a full complement of 

Figure 1—Overview of the foundation science activities of the LTAR network (figure center) resulting in key 

products (middle rectangle) that lead to an array of outcomes (outer ring).
46 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

Societal 

Concerns

Foundation 

Science Research Questions Expected Products

Food, fi ber 

and fuel 

production, 

resource 

sustainability 

and system 

resilience

→ Agroecosystem 

productivity →

How can production 

systems be intensifi ed so 

that inputs decrease and/or 

outputs increase?

• New strategies to improve net primary 

production and crop yields;

• Improved nutrient and water use 

effi ciencies of US food, fi ber and 

bioenergy production systems;

• Quantifi cation of greenhouse gas and 

water footprints and life cycle analyses of 

production systems;

• Better methods to evaluate economic 

value of ecosystem services.

Climate 

variability and 

change

→

Climate 

variability and 

change 

→

How can agroecosystems 

increase production with 

climate change?

What strategies will help 

mitigate greenhouse gas 

emissions?

How can agriculture 

improve water supply and 

quality in the face of climate 

change?

• Improved understanding of recovery 

processes/lags from drought, fl oods or 

other extreme events;

• Carbon or greenhouse gas mitigation 

credits and markets;

• Monitoring and assessment tools that 

support adaptive management.

Water supply 

and quality

→

→

Agricultural 

conservation 

and 

environmental 

quality

→

How can production 

systems be made 

sustainable for both on and 

off-site effects?

How can management 

changes improve resource 

use effi ciency?

• Indicators of soil quality and function;

• Valuation of ecosystem services;

• Scientifi c understanding to underpin 

conservation planning and agricultural 

land management;

• Monitoring and assessment tools 

(models) to support adaptive 

management.

Ecological 

integrity and 

ecosystem 

health

→

Economic 

sustainability 

and 

livelihoods

→

Socioeconomic ties 

to productivity, 

climate and 

environment

→

How can new or 

improved commodities 

be incorporated into 

agroecosystems to sustain 

ecological integrity, 

ecosystem health, and 

economic opportunity?

How do economic 

incentives and public 

policy affect the design and 

adoption of new production 

systems?

• Linkage of georeferenced socioeconomic 

data bases (US Census, ERS-ARMS, Ag 

Census) with biophysical modeling;

• Better understanding of motivation, 

incentives, and barriers to adoption or 

change;

• Better understanding of interactions 

between farm structure and supply of 

agroecosystem goods and services.

Table 2—Summary of LTAR Network Shared Research Questions and Expected Outcomes.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 47

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

Figure 3—The transfer of matter and energy through agroecosystems is both hierarchical and 

continuous through space and time (MLRA: Major Land Resource Area, HUC: Hydrologic Unit 

Code, and NEON: National Ecological Observatory Network).

Figure 2—LTAR will examine the temporal dynamics of anthropogenic and 

environmental impacts across multiple spatial scales.
48 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

Type Measurement Key Considerations 

Plants and 

Animals

Species composition, biomass growth 

and development, harvest yield and 

quality 

Sampling strategies, phenomics, community structure

Plant nutrient concentrations, water 

and nutrient use effi ciencies

Species considered, water and nutrient mass balances, cycles and 

fl ows, spatio-temporal scales, measurement technologies

Geography 

Digital elevation map and terrain 

attributes 

LiDAR-derived, basis for hydrologic modeling, erosion estimates, 

hillslope modeling, terrain analysis

Land cover/use (e.g., forest, range, 

pasture, cropland, water, urban buildup) 

Patch, mosaic structure, spatio-temporal changes in land use/cover 

Remote sensing including multi- and 

hyper-spectral ground-based or satellite 

imagery

Linkage to processes, properties and practices including 

phenomics, water and nutrient stress, biomass accumulation, 

disease/weeds/pests, surface residue, management practices

Weather

Precipitation, air temperature, solar 

irradiation, humidity, wind speed and 

direction, soil microclimate

Measurements required for models and to complement empirical 

data. Linkage to weather networks (e.g., SCAN), interpolation 

metrics (e.g., PRISM) and land management decision support 

(e.g., fl ex cropping, prescribed burning) 

Water

Changes in storage, hydrographs for 

surface and ground water 

Measurements required to characterize base and storm fl ow, 

estimate recharge, permitted withdrawals, other

Evapotranspiration Water use, evaporation at relevant spatio-temporal scales

Water quality Agroecosystem contributions to water at fi eld to watershed scales, 

such as pH, sediment, pathogens, TOC, DOC, NO3

-

, NH4

+, P, O2

, 

temperature, pesticides, and emerging pollutants.

Stream ecology Habitat metrics (e.g., bank condition, bed condition, DO, 

temperature, indicator organisms, shading)

Soil

Soil organic matter (labile, metastable, 

recalcitrant pools, fl uxes), soil 

respiration, biological species, 

communities 

Measurements required for models and to complement related 

data. Statistical approaches (e.g., stratifi ed random sampling). 

Degradation processes (organic matter depletion, decreased 

biological diversity), sensitivity/resiliency concepts

Nutrient availability (e.g., N, P, K, S), 

reaction (pH), toxicity (e.g., Al, Mn, 

Na), EC, mineralization, CEC, base 

saturation

N2

 fi xation, nutrient supplying power (ion exchange membranes, 

resins), acidifi cation, salinization, soil resource sensitivity/resiliency 

concepts

Soil physical properties (texture, 

aggregation, bulk density, infi ltration, 

soil rooting depth, water characteristic 

curves)

Soil degradation processes (e.g., compaction, erosion). Soil 

process, property characterization at appropriate spatio-temporal 

scales considering depth increments, terrain, soil classifi cation. 

Linkage to soil microclimate. 

Soil classifi cation, morphology NRCS soil survey, higher resolution soil survey, descriptions

Air

Greenhouse gas (GHG) fl ux Soil gas exchange (CO2

, N2O, CH4) at relevant spatio-temporal 

scales, GRACEnet and other sites. Eddy covariance fl ux towers, 

static chamber measurements, soil oxygen sensors

Particulate emissions (PM10, PM2.5, 

TSP), deposition (SO2, N compounds), 

organic compounds (e.g., VOC’s, 

agrochemicals)

Linkage to air quality and NADP networks, wind erosion, 

aerosol formation

Management

Agronomic and livestock management 

operations (tillage, planting, 

agrichemical applications), inputs 

(dates, rates, etc.)

Spatio-temporal scales and linkages to water and nutrient use 

effi ciency, soil health, irrigation management

Agricultural practice use (conservation 

farming, precision farming), location 

and size (CAFOs)

Data availability 

Socioeconomics

Characterization of markets, farm 

structure and tenure, demographics, 

preferences, incentives/barriers to 

practice adoption

Survey information (USDA census, other), NASS, ownership, rented 

land, sources of labor

Table 3—Measurements required for LTAR foundation science and related discussion points.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 49

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

measurements, and augmenting this with partial budgets 

at other sites. To better understand drought, flood, erosion, 

vegetation and the impacts of climate change, 16 sites 

have been instrumented with new sensors to monitor soil 

moisture at multiple depths and locations in the past two 

decades. Ideally, shared measurements would be made 

with protocols common not only to LTAR sites, but also 

common to LTER, NEON, and other networks. 

Since most LTAR sites have valuable continuous data 

records extending back decades, it may be unrealistic to 

consider changing all methods to a common protocol. 

In these cases, we will document that methods are 

nearly common, and use various QA/QC techniques to 

validate and compare those methods. Good laboratory 

practices and chain of custody for samples and data will 

be documented. Uncertainty introduced by different 

equipment, sampling and/or analytical methodologies 

(e.g., differentiating forms of phosphorus), sampling 

design (e.g., flume geometry), and scale of observation 

(plot, field, watershed, basin, airshed, etc.) will be 

documented and acknowledged. Though a common 

LTAR analytic center is not envisioned, a funded LTAR 

coordination of methods and protocols is a requirement 

for LTAR success. 

The Common Experiment

The LTAR common experiment will underscore 

sustainable production systems, practices, and strategies 

that conserve the nation’s natural resources and enhance 

environmental quality. In combination with the longterm historical data, data from the common experiment 

will provide a basis for objective evaluation of social, 

ecological and economic factors affecting the viability of 

alternative management strategies for US agriculture. A 

key outcome of this LTAR network common experiment 

is to develop and disseminate multi-regional, sciencebased information that will enable implementation of 

sustainable agriculture production systems that promote 

food security, environmental values, and climate change 

mitigation and adaption.

The objectives of the LTAR network common experiment 

will include:

Develop and evaluate sustainable, profitable 

production systems or management strategies that 

optimize production and/or reduce use of resources 

while enhancing delivery of ecosystem services 

through a) altered plant or animal management 

systems, land use strategies, and production systems, 

b) adoption of intensified management, and/or c) 

employing alternative inputs including improved 

germplasm.

Develop and employ coordinated, rigorous 

measurements of indices of productivity; water, 

nutrient and energy use efficiency; plant productivity; 

soil erosion; soil health; water and air quality; 

water availability; and greenhouse gases. Provide 

regional/national report cards comparing production 

efficiencies and ecosystem services. Utilize 

resulting long-term data sets to detect chronic and 

threshold changes in ecosystem services provided by 

agricultural ecosystems.

Identify, quantify, and understand the ecological 

mechanisms underlying the costs and benefits 

associated with traditional and alternative food/

fuel/fiber production and the provisioning of other 

ecosystem services from agriculture across the 

Nation. 

Use long-term measurements and experimental 

observations to model how ecosystem services from 

traditional and alternative management scenarios 

respond to climate projections years into the future 

and develop management recommendations for 

adapting to climate variability and change. Provide 

site-specific calibrations and sensitivity analyses for 

LTAR core models predicting outcomes. 

Multi-Site Analysis of Historic Data

LTAR sites already perform many common 

measurements, albeit with some differences in specific 

variables and protocols. Measurements are being 

made of temporally continuous and spatially extensive 

meteorological conditions and precipitation events at 

all 18 sites. There are decadal records of basin-scale 

vegetation dynamics at 12 sites. Thirteen sites support the 

high-investment, high-maintenance equipment required to 

make continuous measurements of runoff, sediment yield 

and water quality. Analyses are underway or planned in 

the following areas: 

Agroecosystem productivity and sustainability: The 

LTAR network includes grassland sites across the 

southern U.S. During the early 21st century drought, 

a satellite-based record of above-ground net primary 

production (ANPP) at all sites could be used to 

generalize the functional response of grasslands to 

predicted climate change. Retrospective analysis in a 

natural setting at the regional scale could play a role 

in future grassland research, management and policy.

Climate variability and change: The long-term 

climate records of LTAR sites permit coordinated 

quantification of the magnitude of temperature, 

humidity, and precipitation changes across 

agricultural regions of North America over at least 
50 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

four decades. For a multi-decadal analysis period, 

LTAR sites could be used to establish universal 

climatic descriptors and response variables (e.g., 

productivity, watershed runoff/erosion, pest severity). 

From this continental-scale assessment, we can begin 

to understand the sensitivity of agricultural systems 

to changes in the hydro-climatic conditions across 

the US and North America.

Conservation and environmental quality: Historical 

advocacy for soil conservation and the evolution of 

cropping systems, planting technologies, pest control 

options and tillage practices have produced gradual, 

but profound, changes in US farming systems. The 

diverse soil, water, air, pest, and environmental 

quality data sets of LTAR offer a unique opportunity 

for retrospective analysis of the beneficial and 

unintended consequences of conservation practices 

and programs, from no-till to nutrient and pest 

management. Ecosystem services can be evaluated 

as a result of long-term landscape changes, such 

as, agriculture to urban use, natural ecosystems to 

agriculture, and restoration of natural ecosystems on 

former agricultural lands.

Socio-economic viability and opportunities: There is 

increasing interest in the potential for use of market 

forces to encourage producers and landowners to 

adopt new systems or practices to protect water, soil, 

and atmospheric resources. LTAR data sets can be 

used to quantify impacts of practices on the desired 

endpoints and to improve and validate models that 

are a part of environmental marketing and trading 

programs in the government or private sector. 

LTAR Information Management System (IMS) 

The LTAR IMS provides protocol and services for 

collection, verification, organization, archives, access, 

bases for analyses, and distribution of data associated with 

LTAR network activities. Access to all LTAR information 

will be organized through a web-based LTAR portal 

(Fig. 4). The goal of information management is to build 

and maintain an archive of LTAR data files that are fully 

documented, error free, and organized in useful ways. 

Our protocol for data collection and processing seeks 

maximum interaction between researchers and any data 

users. Development and implementation of the LTAR IMS 

system will occur under the currently constituted USDA 

Big Data and Computing Initiative.

Site and data management involvement will begin with 

the completion of a site-based research metadata survey 

by researchers; this will alert the LTAR network regarding 

any specific study and potential LTAR data sets. Once 

the LTAR IMS is implemented, researchers will then 

complete the required metadata documentation. All 

metadata documentation must be provided with any data 

set made available through our Web-based LTAR data 

portal. The final responsibility for quality assurance (both 

in data and documentation content) will rest with the 

principal investigator who submits the data for inclusion 

in the LTAR IMS.

CONCLUSIONS

A key expectation of LTAR is application of research 

results to solve critical challenges facing agriculture. 

Because research-based applications and their outcomes 

are impacted by continually-changing trends, demands, 

and innovations, the LTAR SRS exploits a mixture of 

data from on-going networked science, new cross-site 

experiments, and long-term historical measurements. 

The long-term integration of foundational science with 

long-term, multi-location experimental data underpins 

the provision of key LTAR products: new knowledge 

of processes and systems, new technologies and 

management practices, improved agro-ecological models, 

and comprehensive, accessible data. Ultimately, LTAR 

is expected to provide a wide array of clients, partners, 

and stakeholders with four basic outcomes: applications 

of new technologies, predictions of resource responses 

to system drivers, linkages to other networks, and 

educational outreach. 

This brief overview of the development and content of 

the LTAR Shared Research Strategy is intended to give 

conference participants a broad understanding of the 

scope and direction of the LTAR network. For more 

detailed discussions, the readers are referred to the full 

LTAR-SRS document (Bryant et al. 2013). 

ACKNOWLEDGMENTS

Numerous scientists from all LTAR sites, as well as 

anonymous reviewers, have contributed to development of 

the LTAR Shared Research Strategy. Their contributions 

are gratefully acknowledged by the authors of this 

proceedings paper. 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 51

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

LITERATURE CITED 

American Society of Agronomy. 2011. Grand challenge. https://www.

agronomy.org/files/science-policy/asa-grand-challenge-2011.pdf.

Bryant, R.; Havstad, K.; Heilman, P.; Kleinman, P.; Moorman, T.B.; 

Moran, M.S.; Steiner, J.L.; Strickland, T. 2013. Long Term 

Agroecological Research Network, shared research strategy. USDA–

ARS. http://ars.usda.gov/ltar (accessed 24 February 2015).

Peters, D.P.C. 2010. Accessible ecology: synthesis of the long, deep, and 

broad. Trends in Ecology and Evolution 25: 592-601.

Walbridge, M.R.; Shafer, S.R. 2011. A long-term 

agro-ecosystem research (LTAR) network for agriculture. 

In: Proceedings 4th Interagency Conference on Research 

in the Watersheds, Fairbanks, AK, 26-30 Sept 2011.

Figure 4—A conceptual model for a data portal framework of LTAR Information Management System providing 

public access to source data, integrated data, derived data products and data interpretations (adapted from 

Peters, 2010).
52 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

PERSPECTIVES ON THE DEVELOPING COMMON EXPERIMENT 

ACROSS THE 18 SITES WITHIN THE LONG TERM 

AGROECOSYSTEM RESEARCH NETWORK

Kris Havstad1

The USDA Agricultural Research Service (ARS) established a Long Term Agroecosystem 

Research Network (LTAR) across 10 of its research locations, including some of its large 

watershed facilities, in 2012 and expanded that network to 18 locations in 2014. The LTAR 

is now designing a common experiment across all 18 locations, which includes 3 non-ARS 

sites, to be implemented in 2016. Though these 18 sites represent a very diverse array of 

agricultural systems, from small grains to beef cattle, and a diverse array of production scales, 

from intensely managed farm fields to extensively managed expansive rangelands, all sites 

share research objectives and hypotheses. The research plan is now being developed through 

2015 for peer review early in 2016. In itself, the development of a common experiment across 

18 diverse locations could be viewed as an experiment in coalescing science and scientists. 

Perspectives on this process, its goals, objectives and hypotheses will be shared by one 

participant in this ambitious effort.

1

Research Rageland Management Secialist, USDA Agricultural Research Service, Jornada Experimental Range, Las Cruces, NM 88003
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 53

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

STORYTELLING TO SUPPORT WATERSHED RESEARCH 

ON EMERGING ISSUES

Philip Heilman1

Projections of budget deficits by the Congressional Budget Office imply ever-increasing 

pressure on federal spending for all purposes, including long-term watershed research. This 

presentation will argue that, since federal funding is ultimately a political decision, those 

responsible for maintaining long-term watershed research programs should not try to provide 

rigorous economic justification. Rather, the effort should recognize the natural human 

tendency to relate to the world through stories, and develop stories so that stakeholders can 

see their “stake” in supporting both ongoing and emerging watershed research.

The essential elements of storytelling are different than scientific communication and require 

a different skillset. Effective storytelling is concrete, requires a source of conflict, provides 

an emotional connection, and focuses on the novel and memorable. In many respects, a 

compelling story for additional watershed research funding will resemble the “dog and pony 

show” entrepreneurs tells venture capitalists when asking for the funds to develop a new 

technology. 

Rigor is required in that an experimental watershed seeking expanded funding has to be able 

to provide new insights related to an emerging issue, the issue has to appeal to stakeholders 

enough to motivate lobbying, the lobbying efforts have to be persuasive enough to motivate 

action from a member of Congress, and finally the member has to be capable of providing 

new funding. If a weak link in that chain makes new funding to address an emerging issue 

unlikely, perhaps a broader organization could be persuaded to lobby for an emerging issue 

that could be addressed by a network of research watersheds. Another fallback position could 

be to remind stakeholders that are dependent on existing products so they lobby to maintain 

current funding levels, if cuts are threatened. An example story to address emerging issues 

related to climate resilience in infrastructure and new sources of manageable water for 

southeastern Arizona using data from the Walnut Gulch Experimental Watershed will illustrate 

the differences between scientific communication and storytelling. 

Scientists would prefer a world in which new funding could be justified on scientific grounds. 

In this world, we will have to address the need to find new funding by working within the 

political system, using the language of politics - storytelling, and ensuring that we provide as 

much tangible value to stakeholders as possible.

1

Research Leader, USDA Agricultural Research Service, Southwest Watershed Research Center, Tucson, AZ 85719
54 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE USDA-ARS EXPERIMENTAL WATERSHED NETWORK – 

EVOLUTION, LESSONS LEARNED, AND MOVING FORWARD

David Goodrich, Phil Heilman, Susan Moran, Jurgen Garbrecht, Danny Marks, 

David Bosch, Jean Steiner, John Sadler, Matt Romkens, Daren Harmel, 

Peter Kleinman, Stacey Gunter, Mark Walbridge1

Abstract—The USDA-Agricultural Research Service’s Experimental Watershed Network grew from Dust Bowl era 

efforts of the Soil Conservation Service in the mid 1930’s with the establishment of watersheds in three States; one of 

which is still in operation. In the mid-50’s five centers with intensively instrumented watersheds at the scale of 100 to 700 

km2 were established. Primary network research objectives were to quantify the field-scale and downstream effects of 

conservation practices and develop rainfall-runoff relationships for design of water conservation structures. USDA-ARS 

has operated over 600 watersheds in its history and continues to operate roughly 120 watersheds, many of which consist 

of gauged subwatersheds nested within larger gauged watersheds to enable investigation of scaling. With passage of the 

Clean Water Act in 1972, research objectives have evolved to add a variety of observations relevant to the water quality 

issues in their respective regions resulting in a more diverse, but less homogeneous network. The core instrumentation 

and related long record of high-quality observations have led to initiation of a series of multi-location projects to examine 

trends and directions of these observations across the network. As a result of their long history, intensive monitoring, and 

well described processes, the USDA-ARS watersheds have been used extensively in the development and validation of 

numerous watershed models. In addition, they served, and continue to serve as validation sites for aircraft and satellite 

based remotely sensed instruments. Many of the USDA-ARS Experimental Watersheds have now joined the Long-Term 

Agro-ecosystem Research Network (LTAR) (Maddox, 2013). This presentation will review major activities and advances 

derived from the network in addition to discussing some lessons learned in the long-term operation of a national scale 

network through its evolution from analog to digital instrumentation and internet accessibility.

INTRODUCTION

Much of the following introductory material is derived 

from Goodrich and others (1993). Depression era efforts 

by the Civil Conservation Corps (CCC) and the Soil 

Conservation Service (SCS) were the catalyst for the 

early USDA-ARS Experimental Watershed Program. 

The early history of the watershed program as we 

know it today is described in more detail by Kelly and 

Glymph (1965). Initial research was motivated by the 

1930’s conservation motto of “stop the water where it 

falls.” It focused on the merits of upstream watershed 

conservation to infiltrate precipitation and hold or slow 

runoff to reduce runoff and erosion. The research was 

largely concerned with on-site problems at the field scale 

on watersheds up to roughly 10 hectares. To a large extent 

the research utilized paired watershed analyses. In 1935 

there was an expansion in scope to examine fields and 

watersheds up to several square kilometers in size with 

the establishment of major research stations in Coshocton, 

OH, and Hasting, NE (Harmel and others, 2007). Plot 

and lysimeter studies were incorporated into the research 

at these locations in addition to continuing the research 

on on-site effects of tillage and management practices. 

The research during this period is largely empirical with 

emphasis on instrumentation and accurate data collection 

(Kelly and Glymph, 1965). There was early recognition 

1

David Goodrich, Hydraulic Engineer, USDA Agricultural Research Service, Tucson, AZ 85719

Phil Heilman, Research Leader, USDA Agricultural Research Service, Tucson, AZ 85719

Susan Moran, Hydrologist, USDA Agricultural Research Service, Tucson, AZ 85719

Jurgen Garbrecht, Hydraulic Engineer, USDA Agricultural Research Service, El Reno, OK 73036

Danny Marks, Hydrologist, USDA Agricultural Research Service, Boise, ID 83712

David Bosch, Hydraulic Engineer, USDA Agricultural Research Service, Tifton, GA 31793

Jean Steiner, Research Leader, USDA Agricultural Research Service, El Reno, OK 73036

John Sadler, Research Leader, USDA Agricultural Research Service, Columbia, MO 65211

Matt Romkens, Collaborator, USDA Agricultural Research Service, Oxford, MS 38655

Daren Harmel, Supervisory Agricultural Engineer, USDA Agricultural Research Service, Temple, TX 76502

Peter Kleinman, Research Leader, USDA Agricultural Research Service, University Park, PA 16802

Stacey Gunter, Research Leader, USDA Agricultural Research Service, Woodward, OK 73801

Mark Walbridge, National Program Leader, USDA Agricultural Research Service, Beltsville, MD 20705
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 55

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

of scaling problems in transferring knowledge from small 

to larger watersheds (Harrold and Stephens, 1965). As a 

result, national programs were developed in the 1950’s 

for controlling floodwaters and sediment, as well as 

assessing downstream effects of conservation practices on 

watersheds up to 1,000 km2. The USDA-ARS was created 

in 1953 and operation and management of many of the 

experimental watersheds established by USDA’s SCS 

were transferred to USDA-ARS.

A major impetus for expansion of the USDA-ARS 

experimental watershed program resulted from hearings 

by the Senate Select Committee on National Water 

Resources. In 1958 this committee conducted nationwide 

hearings and a review of US water resources and policy 

and requested USDA “to make a study of facility needs 

for research on soil and water problems...” The USDA 

study resulted in Senate Document 59 (US. Senate, 1959) 

which identified “Hydrology of Agricultural Watersheds” 

as high priority. The recommendations in this document 

mirror more recent calls for improved research and 

continental-wide observations for water, ecology and soils 

emanating from the National Ecological Observatory 

Network (NEON) and Critical Zone Observatories (CZO) 

(NRC, 2008). Senate Document 59 laid out the following 

national research objective: “Hydrologic studies are 

urgently needed on precipitation-runoff relationships and 

the effect of all types of conservation treatments on runoff 

... from agricultural watersheds ranging in size from 1 

to 400 square miles.” Like NEON they recommended 

core experimental watershed sites with satellite locations 

(“Experimental watersheds are needed in all 15 major 

land resource regions...to provide the maximum 

opportunity for interpolating values between locations 

with markedly contrasting conditions each should include 

a number of satellite locations ...”). The interdisciplinary 

nature of the challenge was also recognized as Senate 

Document 59 stated “...agricultural watershed behavior 

is a complex problem...research centers must be large 

enough to represent numerous disciplines.” While 

cyber-infrastructure had not been contemplated in the 

late 1950’s they did recommend measurement of a 

common set of variables with standard protocols, periodic 

review of network data, and a central data repository in 

Beltsville, Maryland. 

As a result of Senate Document 59, appropriations were 

made to establish new watershed research centers in 

a number of hydroclimatic regions in Chickasha, OK; 

State College, PA; Boise, ID; Tifton, GA; and Tucson, 

AZ. In addition, the Columbia, Missouri research unit 

was directed to become the North Central Hydrologic 

Laboratory in 1961 as a direct result of Senate Document 

59. Analysis of observations from the earlier, smaller 

watersheds indicated the difficulty in extrapolating 

hydrologic response characteristics to larger scales. 

Consequently, the core experimental watersheds 

established at these new centers were on the order of 100 

to 600 km2, roughly an order of magnitude larger than 

watersheds established in the 1930-40’s. The goal of the 

watershed research centers was to select a representative 

core watershed and establish satellites that were less well 

instrumented. Nested watersheds and unit source areas on 

major soil types were included in the watershed designs to 

further investigate scale effects.

A key early challenge in establishing the larger 

experimental watersheds over a wider range of 

hydroclimatic regions was development and acquisition 

of instrumentation and procedures for their installation, 

operation, and maintenance. A significant, and still 

valuable, outcome of this work was development and 

publication of Handbook 224 - Field Manual for Research 

in Agricultural Hydrology (Brakensiek and others, 1979). 

Measurement quality control was and still is an important 

ongoing effort. Johnson et al. (1982) described ARS 

Experimental Watershed data acquisition programs and 

an assessment of the quality of collected data at many 

of the watersheds. Based on data from the Hydrology 

and Remote Sensing Laboratory in Beltsville, Maryland, 

by 1990, ARS had operated over 600 watersheds in 

its history. Of the 600 watersheds, a comprehensive 

database is available from the Hydrology Laboratory 

for 333 of these watersheds (www.ars.usda.gov/ba/

anri/hrsl/wdchome). This database consists of variable 

time-series readings for precipitation and runoff from 

small agricultural watersheds with sufficient detail to 

reconstruct storm hydrographs and hyetographs with 

approximately 16,600 station years of data. Records in the 

Beltsville database run through 1992. Due to budgetary 

constraints, post 1992 records were maintained at 

individual watershed centers. DeCoursey (1992) provided 

an overview of the ARS Experimental Watershed Network 

in operation at that time including a description of the size 

distribution, length of record and primary land use of the 

active watersheds. Approximately 120 ARS watersheds 

are currently active and collecting a variety of data. The 

geographic location of active watersheds is illustrated in 

Figure 1. In many of the locations depicted on this figure, 

multiple watersheds, many nested, exist or have existed. 

Table 1 lists the primary ARS Experimental Watersheds 

and a number of their attributes.

The guidance on instrumentation, installation, calibration, 

and maintenance described in detail in Handbook 

224 led to a relatively uniform national experimental 

watershed network that focused primarily on observations 

of weather, climatology, precipitation, and runoff, in 

addition to detailed characterization of the watersheds. 

Many lessons were learned during the development of the 

large USDA-ARS watersheds. An important finding was 

that meaningful observations were not always possible 
56 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

across the wide range of environments and hydroclimatic 

conditions. Therefore some specialized instrumentation 

or installation procedures were developed to collect 

meaningful data. For example, the snow dominated 

Reynolds Creek Experimental Watershed in Idaho has 

two precipitation gauges at each measurement location. 

One is shielded to reduce wind effects and the second is 

unshielded. When precipitation is primarily in the form of 

snow (at temperatures less than −2.2°C) this installation 

provides more accurate precipitation estimates and also 

enables the interpretation of unshielded dual gauge 

measurement locations (Hanson, 1989). 

With passage of Clean Water Act (CWA) in 1972 many 

of the ARS watersheds began collecting water quality 

data. Due to regional differences in agriculture production 

and practices, the constituents impacting water quality 

(sediment, herbicides, pesticides, nutrients, etc.) vary 

substantially across the network. These differences and 

budgetary limitations led to a divergence in network data 

collection. As digital instrumentation and technology 

advanced the ARS watersheds began the process of 

converting from analog to digital instrumentation, 

primarily in the 1990s and 2000s. However, this was 

done on a location-by-location basis and not uniformly 

across the network. This is largely the result of the ARS 

budgetary framework where individual locations are 

allocated annual budgets. There is not a “network” budget 

for multi-location purchasing and hiring. The changeover 

to digital instrumentation was in many cases more about 

retrofitting existing instrumentation with data loggers and 

telemetry capabilities so the central core measurements 

of climate, weather, precipitation and runoff could still 

maintained. However, a number of new automated sensors 

became available, such as soil moisture probes. The 

performance of these sensors tended to vary across soil 

types and across dry to wet environments. This resulted 

in location-specific choices of soil probes. However, 

coordinated efforts for validation of remotely sensed soil 

moisture products did result in a common soil moisture 

probes for four of the core experimental watersheds 

(Jackson and others, 2010). As climate change awareness, 

increased many locations added energy and carbon 

flux monitoring and more recently soil respiration and 

biogeochemistry. As with soil moisture, these additions 

were done on a location-by-location basis depending on 

available expertise and research goals.

With improved internet connectivity and lack of a central 

data repository, many individual locations undertook 

specific efforts to organize and make their experimental 

watershed data available in easy to use digital form. 

These efforts have proven to be expensive and time 

consuming. Estimated costs of the Data Access Project 

(DAP) for the Walnut Gulch Experimental Watershed in 

Arizona were ~$700,000 to put eight data sets up on the 

web with metadata published in a peer-reviewed journal. 

Annual maintenance was estimated to be $20,000/year 

for IT upgrades, basic QA/QC, and maintenance of data 

loggers and instrumentation (Moran and others, 2009). 

Temperate Oceanic

Subtropical Winter Rain

Desert

Arid Steppe

Temperate Continental

Subtropical Wet

Major Climatic Regions

Figure 1—Location of primary ARS Experimental Watersheds. 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 57

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1) ARS Experimental Watersheds Monitoring ARS Research Unit Unit Location Description Size Land Cover/Use Year Established Climate Discharge Sediment Water Quality Other Southern Plains Range Research Station Woodward, OK 4 plots 16 ha Grazing 1977

X

X

X 1

Southern Piedmont Conservation Research Unit

Watkinsville, GA 7 plots 130 ha Forest/pasture/ crops 1937

X

X

X 1,3,4 5

Grassland Soil and Water Research Laboratory

Temple, TX 20 plots 350 ha Mixed cropping/ forage 1937

X

X

X 1,3 5

North Appalachian Experimental Watershed

Coshocton, OH 400 ha Mixed cropping/ forage 1935

X

X

X 1,3,4 1

Pasture Systems and Watershed management Research Unit

University Park, PA

Watershed WE-38 730 ha Forest/pasture/ crops 1967

X

X 1 5

National Sedimentation laboratory

Oxford, MS

Goodwin Creek 21.5 km2 Mixed cropping/ forage 1981

X

X

X 4

Cropping Systems and Water Quality Research Unit

Columbia, MO

Goodwater Creek 73 km2 Mixed cropping/ forage 1971

X

X

X 1,3 5

Southwest Watershed Research Center

Tucson, AZ

Walnut Gulch 150 km2 Rangeland 1954

X

X

X 1,3

Northwest Watershed Research Center

Boise, ID

Reynolds Creek 240 km2 Range/forest/hay 1960

X

X

X 2 2

Southeast Watershed Hydrology Research 

Center

Tifton, GA Little River 334 km2 Mixed cropping 1967

X

X

X 1,3 1,3,5

Grazinglands Research 

Laboratory

El Reno, OK

Little Washita 610 km2 Grazing with mixed crops 1936

X

X

X 1 1,3,5

Table 1—Selected Attributes of ARS Experimental WatershedsWater Quality: 1 = Nutrient, 2 = Temperature, 3 = Pesticides, 4 = Pathogens | Other: 1 = Flux, Bowen Ratio, 2 = Snow, 3 = Remote Sensing, 4 = Doppler Radar, 5 = Groundwater
58 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

As part of these data availability efforts, a number of 

special journal sections with data and/or research papers 

were developed. They include Slaughter et al. (2001) 

for Reynolds Creek, Idaho; Bosch and others (2007) for 

the Little River, Georgia; Moran and others (2008) for 

Walnut Gulch, Arizona; Langendoen and others (2009) 

for Goodwin Creek, Mississippi; Owens and others 

(2010) for Coshocton, Ohio; Bryant and others (2011) 

for Mahantango Creek, Pennsylvania; Harmel and others 

(2014) for Riesel, Texas; and, Sadler and others (2015) 

for Goodwater Creek, Missouri. While not technically 

part of the early ARS watershed network, Ames, Iowa 

(Walnut Creek) and Oxford, Mississippi (Beasley Lake) 

were established as part of the Management Systems 

Evaluation Areas (MSEA) and Agricultural Systems 

for Environmental Quality (ASEQ) Projects. Synthesis 

publications describing these watersheds and related 

project research are presented by Hatfield and others 

(1999) and Locke (2004). A broader data services 

tool integrated with GIS services named STEWARDS 

(Sustaining the Earth’s Watersheds, Agricultural Research 

Data System) was developed starting in the mid-2000’s 

(Steiner and others, 2008; Sadler and others, 2008). 

It houses data from a number of the ARS cropland 

dominated experimental watershed as well as CEAP 

(Conservation Effects Assessment Project) watersheds. 

ACCOMPLISHMENTS

The USDA-ARS Watershed Research program and its 

experimental watershed network have a lengthy record 

of high-impact accomplishments. Some of the most 

significant include:

• Quantifying the effectiveness of conservation 

practices and BMPs in reducing runoff, erosion, and 

water quality impacts of agricultural production 

• Quantifying the environmental impacts of 

agricultural fertilizers and chemicals at the 

watershed scale

• Developing guidelines for reclamation of disturbed 

lands

• Quantifying the value of riparian ecosystems in 

improving water quality 

• Instrumentation development and hydraulic 

structure design

• Quantifying the effects of floodwater retarding 

structures

• Development and validation of numerous remote 

sensing products 

• Improved water supply forecasting

• Development of numerous, widely used, watershed, 

water quality, and natural resource management 

models

Through its history the ARS Experimental Watersheds 

have been able to maintain continuity of core observations 

(climate, weather, precipitation, runoff) while adapting to 

meet changing research needs and regional issues. 

CURRENT RESEARCH

The rich history of long-term observations within the 

USDA-ARS Experimental Watershed Network has 

afforded the ability to conduct multi-location research 

projects. Current multi-location projects include: 

• Indicators of ecosystem services in agricultural 

watersheds

• Utility of remote sensing for ET and drought 

monitoring and for assimilation into ARS hydrologic 

models

• Remotely-derived estimates of net primary 

production using remotely sensed data across 

precipitation regimes

• Hydro-climatic trends across North America—a 

comparative analysis of historical soil water trends in 

us agricultural lands

• Continental-scale synthesis of high-resolution 

observations from USDA-ARS and other 

experimental watersheds and ranges

• Comparison of eddy covariance flux measurements 

of H2O vapor and CO2 in different environments

• Estimating the impacts of projected climate change 

on regional water availability and quality across 

diverse physiographic regions of the US

LESSONS LEARNED

A number of important lessons were learned in the 

initiation, development, maintenance, and evolution of the 

ARS Experimental Watershed Network that may benefit 

other national observation based research efforts. Several 

are offered herein in no particular order of importance. 

Off-the-shelf instrumentation may not be universally 

suitable over a diverse set of environments. Some degree 

of trial and error will be inevitable in developing suitable 

instruments and siting them to acquire meaningful 

observations. The time and expense for permitting and 

acquiring access can be considerable and should not 

be underestimated. Likewise, the costs of QA/QC for 

observations, archiving, and data delivery are substantial 

and should be examined when contemplating adding 

other core observations to the network. Personnel with 

good technical, field, and fabrication skills are in short 

supply, and current hydrology and watershed management 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 59

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

degree programs typically do not provide this diverse set 

of skills. Science and societal challenges will emerge that 

the network designers did not anticipate, and therefore our 

observational networks had to adapt. Without a centralized 

funding model for the entire network, our watersheds have 

not been able to uniformly integrate these adaptations. In 

many cases, this makes good economic sense. Collecting 

and analyzing runoff samples for a suite of nutrients, 

pesticides, and herbicides is typically of little value in 

western rangeland where those constituents are not part of 

common agricultural practices.

MOVING FORWARD AND CONCLUSIONS

Many of the long-term ARS Experimental Watersheds are 

now part of the Long-Term Agro-ecosystems Research 

(LTAR) network (Steiner and others, 2015). The vision 

of the LTAR network is to enable multi-decadal transdisciplinary and cross-location science to enhance 

the sustainability of the nation’s agro-ecosystems and 

delivery of goods and ecosystem services. Its primary 

goal is to sustain a land-based infrastructure for research, 

environmental management testing, and education that 

enables understanding and forecasting of the Nation’s 

capacity to provide agricultural commodities and 

ecosystem services under changing environmental, 

economic, and societal conditions. Additional details on 

the LTAR network are reported elsewhere in proceedings 

of this conference (Steiner and others, 2015). Several 

efforts are also underway to provide centralized 

experimental watershed data access. One is through the 

National Agricultural Library. The other is to utilize 

community water data services based on the Hydrologic 

Information System (HIS) developed by the Consortium 

of Universities for the Advancement of Hydrologic 

Science, Inc. (CUAHSI - https://www.cuahsi.org/wdc). 

The Reynolds Creek and Walnut Gulch Experimental 

Watershed Centers have reformatted their core data into 

the Observations Data Model (ODM) that allows spatial 

queries for point time series data via WaterOneFlow 

web services. The companion HydroDesktop (http://

hydrodesktop.codeplex.com) is an open source GIS 

enabled desktop application for searching, downloading, 

visualizing, and analyzing hydrologic and climate data 

registered with the Hydrologic Information System.

Moving forward, the USDA-ARS Experimental 

Watershed Network and LTAR must tackle several 

challenges to ensure its continued relevancy to the 

nation’s natural resource science and management 

priorities. What new core observations, beyond the 

existing observations of weather, climate, precipitation 

and runoff, should be added to the entire network? 

Candidates include trace gases, water and wind erosion, 

ET and CO2 fluxes, and imaging, among others. In 

addition to an expanded set of core observations, how 

will the network evolve to not only incorporate new 

technology and address new regional issues, but also 

collect measurements that may be regionally important for 

a subset of the network and not for other portions of the 

network? A key point is that these are research networks 

and not purely data collection observatories. As such, 

watershed network evolution cannot be solely driven by 

standardized instrumentation, uniform long-term data 

collection for all variables, and centralized database 

management. As a research network it should address 

common national issues that require region-specific 

data collection to address region-specific problems, and 

develop high-impact region-specific solutions. It is the 

capacity of this unique network to address national issues 

across the physiographically and environmentally diverse 

regions of the continent that defines the network, not the 

assemblage of region-specific data of the various ARS 

watersheds and rangelands dispersed across the continent.

ACKNOWLEDGMENTS

This analysis would not have been possible without the 

many early Soil Conservation Service and ARS scientists 

and administrators who had the vision and commitment 

to construct and operate the entire ARS National 

Experimental Watershed Network for the long-term. In 

addition we commend and gratefully acknowledge the 

dedication of ARS staff in maintaining these long-term 

hydrologic observatories and their diligent long-term 

collection of high quality watershed data.

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Bosch, D.D.; Sheridan, J.M.; Lowrance, R.R. [and others]. 2007. Little 

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Harmel, R.D.; Bonta, J.V.; Richardson, C.W. 2007. The original USDAARS experimental watersheds in Texas and Ohio: Contributions 

from the past and visions for the future. Transactions of the 

American Society of Agricultural and Biological Engineers. 50 (5): 

1669-1675.

Harmel, R.D.; Haney, R.L.; Smith, D.R. [and others]. 2014. USDAARS Riesel Watersheds, Riesel, Texas, USA: Water quality research 

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Hatfield, J.L.; Jaynes, D.B.; Burkart, M.R. [and others]. 1999. Water 

Quality in Walnut Creek Watershed: Setting and Farming Practices. 

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4256-4272.

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Representative and Experimental Areas. International Association for 

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Hungary. 5-11.

Langendoen, E.J.; Shields, D.F.; Römkens, M.J. 2009. The National 

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changing agricultural environment. Ecohydrology. 2(3): 227-234.

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of our agroecosystems. Crop Science Society of America News. 

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Moran, M.S.; Emmerich, W.E.; Goodrich, D.C.; [and others]. 2008. 

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National Research Council. 210 p. 

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erosion, and water quality database. Journal of Soil Science Society 

of America. 74(2): 619-623.

Sadler, E.J.; Steiner, J.L.; Chen, J.S.; [and others]. 2008. Sustaining 

the Earth’s Watersheds-Agricultural Research Data System: Data 

development, user interaction, and operations management. Journal 

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the Earth’s Watersheds-Agricultural Research Data System: 

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Conservation. 63(6): 569-576.

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research strategy. Proceedings of the 5th Interagency Conference on 

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Proceedings of the Fifth Interagency Conference on Research in the Watersheds 61

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

CENTRAL MISSISSIPPI RIVER BASIN LTAR SITE OVERVIEW

Edward J. Sadler, Claire Baffaut, Kenneth A. Sudduth, Robert N. Lerch, Newell R. 

Kitchen, Earl D. Vories, Kristen S. Veum, and Matt A. Yost1

Abstract—The Central Mississippi River Basin (CMRB) member of the Long-Term Agro-ecosystem Research (LTAR) 

network is representative of the southern Corn Belt, where subsoil clay content makes tile drainage challenging and make 

surface runoff and associated erosion problematic. Substantial research infrastructure has been in place for more than 40 

years, and the recent establishment of the CMRB LTAR site has prompted additional activity. This paper describes a brief 

history of the research infrastructure, points to resources for further details of documentation and access for research data 

obtained to date, and describes current plans for expansion.

INTRODUCTION

The Central Mississippi River Basin (CMRB) member 

of the Long-Term Agro-ecosystem Research (LTAR) 

network is operated by the USDA-ARS Cropping Systems 

and Water Quality Research Unit in Columbia, Missouri. 

The CMRB LTAR represents a runoff-prone (despite 

gentle slopes) geophysical context with documented 

erosive soils found in the southern Corn Belt. Land, 

originally prairie dissected by wooded riparian river 

corridors, is intensely agricultural. The primary row crops 

are soybean, corn, and sorghum, and forage is mainly 

tall fescue. However, row crop production in this region 

is economically marginal and environmentally risky. In 

contrast to the rest of the Corn Belt, the CMRB area is not 

tile drained.

The core research infrastructure is the 73 km2 Goodwater 

Creek Experimental Watershed (GCEW). Rain gauge 

network data have been collected since 1969 and 

streamflow and sediment load since 1971. In 1991, water 

quality measurements were added for surface and ground 

water. Scales studied ranged from plots at 0.0034 km2, 

to whole fields at 0.12 to 0.35 km2, to streams up to 73 

km2. In 2005, 12 larger-scale watersheds (200 to 1200 

km2) within the Salt River basin were instrumented; 8 of 

these were co-located with USGS flow sites. Since 2010, 

3 of the 12 have been retained for a maximum area of 466 

km2. Collateral infrastructure includes cooperator research 

facilities proximal to and nearly surrounding GCEW. 

The 0.34-ha plots are replicated treatment comparisons 

with summit, backslope, and footslope landscape 

positions, in place since 1991, with yield measured for 

the landscape positions. Eighteen of the 30 have been 

instrumented to measure flow and sample water quality. 

Adjacent is a 35-ha field (Field 1, or F1) managed 

conventionally from 1992-2004, and then converted to 

a “Precision Agriculture System” (PAS). The PAS was 

developed with input from stakeholders on four criteria 

(profitability and environmental impact for erosion, 

surface water quality, and ground water quality). The 

PAS includes no-till, cover crops, wheat instead of corn 

where the topsoil was thin, reflectance-based site-specific 

N applications for wheat and corn, grid-sample-based 

variable-rate P, K, and lime, and targeting of herbicides. 

A close parallel treatment to the PAS also exists in the 

plots. Another plot treatment represents conventional 

production. 

Substantial infrastructure development is underway. 

A conventional practice field (Field 3, or F3) to serve 

as Business as Usual (BAU) will be instrumented for 

surface runoff sampling and measurement and a flux 

tower. Upgrades to existing flow and sampling equipment 

are underway, and a historical GCEW stream site at 

12 km2 is being re-installed to help differentiate the 

urban influence at the headwaters. Radio telemetry has 

been implemented for the rain gauge network and will 

extend throughout the 72 km2 GCEW. Multiple modes 

1

Edward J. Sadler, Research Leader, USDA Agricultural Research Service, Cropping Systems and Water Quality Research, Columbia, MO 65211

Claire Baffaut, Research Hydrologist, USDA Agricultural Research Service, Cropping Systems and Water Quality Research, Columbia, MO 65211

Kenneth A. Sudduth, Agricultural Engineer, USDA Agricultural Research Service, Cropping Systems and Water Quality Research, Columbia, MO 65211

Robert N. Lerch, Research Soil Scientist, USDA Agricultural Research Service, Cropping Systems and Water Quality Research, Columbia, MO 65211

Newell R. Kitchen, Research Soil Scientist, USDA Agricultural Research Service, Cropping Systems and Water Quality Research, Columbia, MO 65211

Earl D. Vories, Agricultural Engineer, USDA Agricultural Research Service, Cropping Systems and Water Quality Research, Columbia, MO 65211

Kristen S. Veum, Research Soil Scientist, USDA Agricultural Research Service, Cropping Systems and Water Quality Research, Columbia, MO 65211

Matt A. Yost, Research Soil Scientist, USDA Agricultural Research Service, Cropping Systems and Water Quality Research, Columbia, MO 65211
62 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

of telemetry are being implemented in the intensively 

studied field site that includes the aspirational practice 

(ASP) and replicated plots of multiple cropping systems, 

including ASP and BAU. An overview of the physical 

infrastructure, telecommunications, and vision for the data 

communications plan is presented below.

PHYSICAL CONTEXT AND HISTORY

At the broad scale, the CMRB comprises a range of 

ARS and University of Missouri infrastructure (fig. 1) 

The core, established in 1971, is within GCEW. The 

ARS Cropland CEAP (Conservation Effects Assessment 

Project) broadened the scope to the entire Mark Twain 

Lake, which catches the upper Salt River basin and 

serves as primary drinking water supply to more than 

40,000 residents over much of northeast Missouri. 

From 2004 to 2011, 12 sites, including GCEW, were 

sampled on a seasonal basis with automated samplers, 

and manually on a biweekly basis through the rest of 

the year where continuous flow from USGS stations 

existed. Surrounding the Salt River Basin are a number 

of USDA and University of Missouri Research Centers 

(RC) that provide controlled space to test hypotheses and 

provide contexts for comparison and contrasts. These 

include the Greenley RC, Bradford RC, South Farm RC, 

Horticulture and Agro-Forestry RC, Tucker Prairie (relic 

native prairie), Prairie Forks Conservation Area (restored 

prairie), Baskett Wildlife RC (forested Ameriflux site), 

and NRCS Plant Introduction Center at Elsberry. 

Within the infrastructure shown in figure 1, the Long 

Branch Watershed remains the focus of current research 

(fig. 2). At this scale, the riparian forests are clearly 

visible, and the predominance of cropland in the broad, 

flat divides between the watersheds is also clear. From 

the Lower Long Branch USGS flow station, there is a 

nested flow structure through Young’s Creek, then the 

GCEW itself. From 1971 to ~2000, the GCEW design 

was a 3-stage nested structure, with 72, 28, and 12 km2

watersheds up the main stem (on the west). In parallel 

with Young’s Creek is Upper Long Branch. The latter two 

are natural channels; Lower Long Branch has a low-water 

crossing as control.

The nested design within GCEW is visible in figure 

3, with Weirs 1, 9, and 11 annotated below. In 1990, 

intensive infrastructure was established at the field and 

Figure 1—The Central Mississippi River Basin LTAR location and associated 

research infrastructure. For reference, the gray area at the extreme SE corner is 

Saint Louis, and the CSWQRU annotation is in Columbia MO.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 63

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

plot scale. The fields are visible in figure 2, as clusters 

of well nests that were established in the 1990s, as is the 

current deployment of weighing rain gauges. 

Intensive research infrastructure at the primary field 

site is shown in figure 4. The right half of the image 

is a 35-ha field with a weir to gauge runoff and an 

automated sampler to enable laboratory measurement 

of sediment, nutrient, and pesticide water quality. The 

site annotated as weather station includes both an ARS 

weather station deployed since 1993 and an NRCS SCAN 

station recently installed (id: CMRB LTAR). To the left 

are 30 plots of 0.34-ha size, arranged in 3 replications 

of 10 cropping systems treatments. All are separated by 

surface berms and in-ground curtains to prevent cross-plot 

movement of water and soluble constituents. Eighteen 

of these also have berms at the bottom that route surface 

runoff through concrete approaches and flumes that are 

instrumented with automated samplers. These have been 

constructed with heated stilling wells to enable sampling 

during periods with temperatures near freezing. They 

are controlled with separate dataloggers, and stage is 

measured using a pressure transducer with in-house 

calibration and temperature compensation algorithms that 

improve accuracy.

Description of the CMRB/GCEW Database 

The data from the CMRB/GCEW was recently 

documented in a multi-paper special collection in the 

Journal of Environmental Quality (http://www.ars.usda.

gov/Research/Docs.htm?docid=25264). The introduction 

includes the scientific, physical, and historical context 

for the research infrastructure (Sadler et al, 2015a). 

Papers describing data for weather (Sadler et al, 2015b), 

streamflow (Baffaut and others 2015b), and both herbicide 

(Lerch and others 2015b) and nutrient (Lerch and others 

2015c) water quality follow. The series includes four 

research papers that address groundwater nutrients 

(Kitchen and others 2015), stream transport of nutrients 

(Lerch and others 2015a), and remote sensing of lake 

water quality (Sudduth and others 2015), plus modeling 

of the GCEW scale using the SWAT model (Baffaut 

and others 2015a). The series makes extensive use of 

supplemental online materials, and potential users of 

the data are strongly encouraged to examine that. The 

contents of the papers and the supplemental online 

materials are also described in more detail through the 

link. In addition, several additional earlier publications 

are listed (and linked) that provide critical information 

regarding sediment (Baffaut and others 2013), hydrologic 

Figure 2—Research infrastructure in the Long Branch watershed of the Salt River.
64 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

methods (Baffaut and others 2014), and the cropping 

systems in the research fields and plots (Lerch and others 

2005; Kitchen and others 2005, Lerch and others 2008). 

The data described in this series are available to the public 

through the STEWARDS database system (Steiner and 

others 2008a; 2009a, b; Sadler and others 2008).

In addition, extensive soil quality assessments have been 

conducted at the field and plot scale at the GCEW site 

(Fig. 4). In 2008, a baseline assessment was initiated on 

all GCEW management systems, and included a broad 

range of soil physical, chemical, and biological indicators 

of soil quality. The soil quality assessments were repeated 

in 2010 and 2014, and will continue to be periodically 

done to evaluate the long-term effects of management 

practices.

Telecommunications development

At this time, the GCEW raingauge network is linked with 

a radio-frequency telecommunications network to a tower 

and base station located at the Field 1 weir site. This 

network is expected to provide the telecommunications 

backbone for all instruments outside the Field 1 campus, 

plus the weather station, rain gauge, and planned flux 

towers within Field 1. Another, lower power, network 

connects the dataloggers on the plot flumes north of the 

building and is expected to be able to accept other closerange equipment in that area. Both of these networks will 

connect to a server in the on-site building. That server 

will connect through a local ISP to the internet, where 

servers at the Columbia ARS offices exist. The server also 

will host WiFi for the field site, providing data access via 

smartphones and laptops and receiving camera images 

and video feeds for both security and research purposes.

The server will provide local control and storage, and 

automatically forward data, as it is received, to the 

Columbia servers. Scientists will normally access data 

from the Columbia servers, such that the field server 

would function as backup. In operation, raw data are not 

overwritten but rather, edits are added as a separate data 

product with metadata describing the replacement or 

transformation. Primary quality assurance (QA) through 

outlier screening will be performed at dataloggers or the 

field server, with reports and alerts contingent on those 

screens. Secondary QA will be performed by technicians 

and scientists during normal work hours, usually on 

Figure 3—Infrastructure visible at the Goodwater 

Creek Experimental Watershed scale.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 65

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

a timeframe from daily to monthly, depending on the 

data stream. This level would involve lab and field 

standards, cross-site or cross-instrument comparisons, and 

comparisons with long-term normal data as appropriate. 

Tertiary QA is done on the annual cycle and involves 

those and additional comparisons plus statistical 

comparisons with related or similar instruments. This 

latter step is required before provisional data is tagged as 

final.

Planned Research Equipment 

Eddy flux towers will be installed in Field 1 as ASP 

(2015 season) and in Field 3 as BAU (2016) (see fig. 3 

for sites). A parallel comparison across two instrument 

types will be established in Field 1 (2015). Averages at 

30-minute intervals will be transmitted and forwarded 

using on-board post-processing. The high-frequency data 

will be moved to the server on a weekly basis via storage 

modules. 

The Field 3 BAU site has an existing weir for measuring 

runoff, but flow measurement and sampling equipment 

were removed some years ago. Modern versions of that 

equipment will be installed, and data communication 

established. Once that is operable, a water sampling 

protocol for the site will be established and implemented. 

Similarly, the Weir 11 site was operable from 1971 

through 2002, at which time the instrumentation was 

removed, but the weir remained. Modern equivalents 

to the instrumentation and sampling equipment will be 

installed. The Field 3 and Weir 11 sites are high priorities. 

Upgrading the larger stream sites will involve similar 

activities – obtaining permissions from right-of-way 

jurisdictions and landowners, establishing power, building 

the platform and housing, installing sampling equipment 

and flow instruments, and establishing communications 

(cellular modem at those sites). They will be sequenced 

after the Field 3 and Weir 11 sites.

Historical rainfall data in GCEW was measured with 

unshielded weighing rain gauges. The SCAN station 

and other automated stations use unshielded tipping 

bucket gauges. The LTAR requirement is expected to 

be a shielded weighing rain gauge. For longitudinal and 

cross-instrument purposes, statistical descriptions of the 

relationships among these instruments are required. A 

2x2 measurement design will be established at the Field 1 

Figure 4—Infrastructure at the Goodwater Creek Experimental Watershed 

Field 1 site.
66 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

weather station site, exploiting the existing unshielded 

weighing and tipping bucket gauges and adding the 

equivalents with double alter shields, all at the same 

height. This deployment will include air temperature and 

wind speed at the height of the gauges, as relationships 

among these gauges is known to depend on wind, and 

temperature is expected to provide correlation to both 

seasonal droplet size and rain vs snow relationships.

Similarly, SCAN weather stations use a type of soil 

moisture measurement that is known to have difficulties in 

soils with high fractions of 2:1 lattice clays, as exist at this 

site. An alternative instrument that is expected to perform 

better in the local soils will be installed in parallel and 

proximal to the SCAN instruments, and the necessary 

relationship established. Gravimetric soil moisture and 

bulk density measurements will be made on a periodic 

basis for calibration purposes.

The SCAN weather station automatically uploads 

hourly and daily data to the NRCS weather data server. 

Software has been developed locally to extract data from 

the NRCS server. It will be adapted to operate on the 

native time basis and create a local copy of those data 

for cross-instrument comparisons and QA purposes. The 

ARS weather station will be relocated approximately 

10 m north to escape the shadow of the SCAN radio 

antenna during the winter months, and upgraded to 

current equipment and sensors at that time. Programming 

to match the 5-minute near real time frequency of the 

University of Missouri AgEBB weather station mesonet 

will be implemented at that time. Software to transmit 

the data to the AgEBB will be implemented as well as 

storing on the field and office servers. A second AgEBB 

weather mesonet station will be established near the Paris 

MO high school, where weekly maintenance will be 

performed by students as a vocational education activity. 

Facilities Plans

The current building on the field site is a 24x12-m 

metal frame construction, with 1/3 floored and a small 

area heated and air conditioned. The rest is used for 

farm equipment storage. A project starting this year 

will add ~32x12m under roof, with about half farm 

equipment storage and the rest electronic and hydrologic 

workshop, multi-purpose space for farm machinery setup, 

instrumentation, repair, and field day/meeting area, and 

restroom/shower facilities. Architectural and engineering 

work will begin in 2015, with construction intended for 

2016.

LITERATURE CITED

Baffaut, C.; Ghidey, F.; Sadler, E.J. [and others]. 2015aa. Long-term 

agro-ecosystem research in the central Mississippi River Basin: 

SWAT simulation of flow and water quality in the Goodwater Creek 

Experimental Watershed. Journal of Environmental Quality. 44: 

84-96. 

Baffaut, C.; Ghidey, F.; Sudduth, K.A. [and others]. 2013. Long-term 

suspended sediment transport in the Goodwater Creek Experimental 

Watershed and Salt River Basin, Missouri, USA. Water Resources 

Research. 49(11): 7827-7830. 

Baffaut, C.; Sadler, E.J.; Ghidey, F. 2014. A methodology to reduce 

uncertainties in the high-flow portion of a rating curve. Transactions 

of the American Society of Agricultural and Biological Engineers. 

57: 803-813. 

Baffaut, C.; Sadler, E.J.; Ghidey, F. 2015b. Long-term agro-ecosystem 

research in the Central Mississippi River Basin: Goodwater Creek 

Experimental Watershed flow data. Journal of Environmental 

Quality. 44: 18-27. 

Kitchen, N.R.; Sudduth, K.A.; Myers, D.B. [and others]. 2005. 

Development of a conservation-oriented precision agricultural 

system: Crop production assessment and plan implementation. 

Journal of Soil and Water Conservation. 60(6): 421-430. 

Kitchen, N.R.; Blanchard, P.E.; Lerch, R.N. 2015. Long-term agroecosystem research in the Central Mississippi River Basin: 

Hydrogeologic controls and crop management influence on nitrates 

in loess and fractured glacial till. Journal of Environmental Quality. 

44: 58-70. 

Lerch, R.N.; Baffaut, C.; Kitchen, N.R. [and others]. 2015a. Long-term 

agro-ecosystem research in the Central Mississippi River Basin: 

Dissolved nitrogen and phosphorus transport in a high runoff 

potential watershed. Journal of Environmental Quality. 44: 44-57. 

Lerch, R.N.; Baffaut, C.; Sadler, E.J. [and others]. 2015b. Long-term 

agro-ecosystem research in the Central Mississippi River Basin: 

Goodwater Creek Experimental Watershed and regional herbicide 

water quality data. Journal of Environmental Quality. 44: 28-36. 

Lerch, R.N.; Kitchen, N.R.; Baffaut, C. [and others]. 2015c. Long-term 

agro-ecosystem research in the Central Mississippi River Basin: 

Goodwater Creek Experimental Watershed and regional nutrient 

water quality data. Journal of Environmental Quality. 44: 37-43. 

Lerch, R.N.; Kitchen, N.R.; Kremer, R.J. [and others]. 2005. 

Development of a conservation-oriented precision agricultural 

system: Water and soil quality assessment. Journal of Soil and Water 

Conservation. 60(6): 411-421. 

Lerch, R.N.; Sadler, E.J.; Kitchen N.R. [and others]. 2008. Overview 

of the Mark Twain Lake/Salt River Basin conservation effects 

assessment project. Journal of Soil and Water Conservation. 63(6): 

345-359. 

Sadler, E.J.; Lerch, R.N.; Kitchen, N.R. [and others]. 2015a. Long-term 

agro-ecosystem research in the Central Mississippi River Basin: 

Introduction, establishment, and overview. Journal of Environmental 

Quality. 44: 3-12. 

Sadler, E.J.; Steiner, J.L.; Chen, J.S [and others]. 2008. STEWARDS 

Watershed Data System: User perspective, operation, and 

application. Journal of Soil and Water Conservation. 63(6): 577-589. 

Sadler, E.J.; Sudduth, K.A.; Drummond, S.T. [and others]. 2015b. Longterm agro-ecosystem research in the Central Mississippi River Basin: 

Goodwater Creek Experimental Watershed weather data. Journal of 

Environmental Quality. 44: 13-17. 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 67

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

Steiner, J.L.; Sadler, E.J.; Chen, J.S. [and others]. 2008a. STEWARDS 

Watershed Data System: Overview. Journal of Soil and Water 

Conservation. 63(6): 569-576.

Steiner, J.L.; Sadler, E.J.; Hatfield, J.L. [and others]. 2009a. Data 

management to enhance long-term watershed research: Context and 

STEWARDS case study. Journal of Ecohydrology. 2: 391-398. 

Steiner, J.L.; Sadler, E.J.; Wilson, G. [and others]. 2009b. STEWARDS 

watershed data system: system design and implementation. 

Transactions of the American Society of Agricultural and Biological 

Engineers. 52(5): 1523-1533. 

Sudduth, K.A.; Jang, G.; Lerch, R.N. [and others]. 2015. Long-term 

agro-ecosystem research in the Central Mississippi River Basin: 

Hyperspectral remote sensing of reservoir water quality. Journal of 

Environmental Quality. 44: 71-83. 
68 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE SOUTHERN PLAINS LTAR WATERSHED RESEARCH PROGRAM

Patrick Starks, Jean L. Steiner1

Water connects physical, biological, chemical, ecological, and economic forces across the 

landscape. While hydrologic processes and scientific investigations related to sustainable 

agricultural systems are based on universal principles, research to understand processes 

and evaluate management practices is often site-specific in order to achieve a critical mass 

of expertise and research infrastructure to address spatially, temporally, and ecologically 

complex systems. The USDA-ARS Grazinglands Research Laboratory (GRL) is host to the 

Southern Plains Long-term Agricultural Research site (SP-LTAR), and watershed research 

at the SP-LTAR began in the Upper Washita River basin of Oklahoma in 1961 and continues 

to present. The two primary research watersheds in this area are the 610 km2 Little Washita 

River Research Watershed and the 800 km2 Fort Cobb Reservoir Experimental Watershed. The 

size of these watersheds, coupled with the fact that 100 percent of land in both watersheds is 

privately owned, precludes meaningful manipulative experiments. However, research efforts 

in these two watersheds have made significant contributions in the areas of development 

of climate generators, model development and evaluation, remote sensing research, and 

sediment source tracking. Most of the data sets from these watersheds were highlighted in a 

special issue of the Journal of Environmental Quality and are publicly available. Eight unit 

source (1.6 ha) watersheds were established at the GRL in 1979 for the purpose of studying 

the effects of crop, crop management, grazing, and grazing management on water quality 

and quantity. Research from these watersheds has contributed greatly to our understanding 

of the impacts of crop type and crop and animal management on soil erosion and water 

quality. However, these small watersheds do not completely capture the dynamics and 

processes unique to agricultural production on larger land units. Thus, ten 16 ha productionlevel (P-L) watersheds are being established at the GRL to study the impacts of crop and 

livestock production and conservation practice effects on the local water budget and on water 

quality. Data from the unit source and P-L watersheds will be used to address issues related 

to Southern Plains agriculture, help improve field-scale hydrologic models, and address 

components of both the Pasture and Cropland Conservation Effects Assessment Program.

1

Patrick Starks, Research Soil Scientist, USDA Agricultural Research Service, Grazinglands Research Laboratory, El Reno, OK 73036

Jean L. Steiner, Supervisory Soil Scientist, USDA Agricultural Research Service, Grazinglands Research Laboratory, El Reno, OK 73036
Mercury Fate, Transport, and Bioaccumulation 

in Wetland Influenced Ecosystems: 

Field Studies and Modeling
70 Headwaters to Estuaries: Advances in Watershed Science and Management

Mercury Fate, Transport, and Bioaccumulation in Wetland Influenced Ecosystems: Field Studies and Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

IMPACT OF BASIN SCALE AND 

TIME-WEIGHTED MERCURY METRICS ON 

INTRA-/INTER-BASIN MERCURY COMPARISONS

Paul Bradley, Mark E. Brigham1

Understanding anthropogenic and environmental controls on fluvial Mercury (Hg) 

bioaccumulation over global and national gradients can be challenging due to the need to 

integrate discrete-sample results from numerous small scale investigations. Two fundamental 

issues for such integrative Hg assessments are the wide range of basin scales for included 

studies and how well discrete samples capture the characteristically high temporal variability 

of fluvial biogeochemistry, seasonally and over shorter time spans. 

To assess inter-comparability of fluvial Hg observations at substantially different scales, Hg 

concentrations, yields, and bivariate-relations were evaluated at nested-basin locations in 

the Edisto River, South Carolina and Hudson River, New York. Differences between scales 

were observed for filtered methylmercury (FMeHg) in the Edisto (attributed to wetland 

coverage differences) but not in the Hudson. Total mercury (THg) concentrations and 

bivariate-relationships did not vary substantially with scale in either basin. Results indicated 

that small (<80 km2) basin studies provide a reasonable foundation for development of 

orders of magnitude up-scaled conceptual or numerical models for application at large-basin 

and regional scales with comparable landscape characteristics. Combined with the lack 

of significant correlation between study basin size and estimates of mean annual FMeHg 

concentration across a national gradient, these results indicate that differences in basin scale 

as such are not a primary concern when integrating individual study results over global and 

national gradients if geospatial measures of wetland coverage and stream connectivity are 

included.

The inability to use automated sampling procedures for ultra-clean MeHg sampling and 

the cost of MeHg analyses preclude continuous or near-continuous MeHg sampling 

and substantially limit the number of collected discrete MeHg water samples. Thus, 

the representativeness of discrete sampling regimes is a fundamental concern in fluvial 

environments, which typically exhibit much more spatial and temporal variability in Hg 

concentrations than do lacustrine systems. Consistent with numerous previous studies, fish 

Hg correlated strongly with sampled water FMeHg concentration (ρ = 0.78; p = 0.003). 

However, improved correlation (ρ = 0.88; p < 0.0001) was achieved with time-weighted mean 

annual FMeHg concentrations estimated from basin-specific LOADEST models and daily 

streamflow. The results of this study illustrated that continued optimization of numerical 

tools to interpolate Hg concentrations over select life-cycle time periods will improve our 

understanding of the linkages between fluvial Hg concentrations and bioaccumulation.

1

Paul Bradley, Hydrologist, US Geological Survey, Columbia, SC 29210

Mark E. Brigham, Hydrologist, US Geological Survey, Mounds View, MN 55112
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 71

Mercury Fate, Transport, and Bioaccumulation in Wetland Influenced Ecosystems: Field Studies and Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATERSHED CYCLING OF MERCURY AND 

CONTROLS ON METHYLMERCURY PRODUCTION IN 

NORTHERN MINNESOTA LANDSCAPES

Randy Kolka, Carl Mitchell, Ed Nater1

Mercury is the number one contaminant in surface waters of the U.S. because of health 

concerns for both humans and other animals when they consume fish. The form of 

mercury that bioaccumulates in the food chain is an organically complexed form known as 

methylmercury. Over the past 20 years we have conducted research to understand the mercury 

cycle in Northern Minnesota landscapes. Notable studies have characterized how both total 

mercury and methyl mercury cycles in peatland watersheds, the controls on the production 

of methylmercury, the effect of increasing sulfate deposition on mercury fluxes in both water 

and biota, and the influence of forest fire on mercury cycles. We will discuss these studies and 

summarize the current state of knowledge on mercury cycling in these landscapes.

1

Randy Kolka, Research Soil Scientist, USDA Forest Service, Northern Research Station, Grand Rapids, MN 55744

Carl Mitchell, Associate Professor, Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, 

ON, Canada M1C-1A4

Ed Nater, Professor, Department of Soil, Water and Climate, University of Minnesota, St. Paul, MN 55108
72 Headwaters to Estuaries: Advances in Watershed Science and Management

Mercury Fate, Transport, and Bioaccumulation in Wetland Influenced Ecosystems: Field Studies and Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

SENSITIVITY OF STREAM METHYL HG 

CONCENTRATIONS TO ENVIRONMENTAL CHANGE IN THE 

ADIRONDACK MOUNTAINS OF NEW YORK, USA

Doug Burns, Karen Riva Murray, Elizabeth A. Nystrom, 

David M. Wolock, Geofrey Millard, Charles T. Driscoll1

The Adirondacks of New York have high levels of mercury (Hg) bioaccumulation as 

demonstrated by a region-wide fish consumption advisory for children and women who 

may become pregnant. The source of this Hg is atmospheric deposition that originates from 

regional, continental, and global emissions. Soils in the region have large Hg stores equivalent 

to several decades of atmospheric deposition suggesting that the processes controlling Hg 

transport from soils to surface waters may greatly affect Hg concentrations and loads in 

surface waters. Furthermore, Hg can be converted to its neuro-toxic methyl form (MeHg), 

particularly in riparian and wetland soils where biogeochemical conditions favor net 

methylation. We measured MeHg concentrations during 33 months at Fishing Brook, a 65 km2

catchment in the upper Hudson River basin in the Adirondacks. Seasonal variation in stream 

MeHg concentrations was more than tenfold, consistent with temperature-driven variation 

in net methylation rates in soils and sediment. These data also indicate greater than twofold 

annual variation in stream MeHg concentrations among the three monitored growing seasons. 

The driest growing season had the lowest MeHg concentrations, and these values were 

greater during the two wetter growing seasons. We hypothesize that contact of the riparian 

water table with abundant organic matter and MeHg stored in the shallowest soil horizons is 

a dominant control on MeHg transport to the stream. An empirical model was developed that 

accounted for 81 percent of the variation in stream MeHg concentrations. Water temperature 

and the length of time the simulated riparian water table remained in the shallow soil were 

key predictive variables, highlighting the sensitivity of MeHg to climatic variation. Future 

changes in other factors such as Hg emissions and deposition and acid deposition will likely 

also influence stream MeHg concentrations and loads. For example, lime application to an 

Adirondack stream to increase pH and enhance ecosystem recovery from acidification has 

increased MeHg concentrations, which may be associated with parallel increases in dissolved 

organic carbon concentrations. Future changes in the Hg cycle of this region will likely be 

complex, reflecting changes in climatic drivers and emissions of Hg and other air pollutants.

1

Doug Burns, Hydrologist, US Geological Survey, Troy, NY 12180

Karen Riva Murray, Ecologist, US Geological Survey, Troy, NY 12180

Elizabeth A. Nystrom, Hydrologist, US Geological Survey, Lawrence, KS 66049

David M. Wolock, Hydrologist, US Geological Survey, Lawrence, KS 66049

Geoffrey Millard, Civil and Enviornmental Engineering Graduate Student, Syracuse University, Syracuse, NY 13244

Charles T. Driscoll, Professor, Syracuse University, Syracuse, NY 13244
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 73

Mercury Fate, Transport, and Bioaccumulation in Wetland Influenced Ecosystems: Field Studies and Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

OPTIMIZING FISH AND STREAM-WATER MERCURY METRICS 

FOR CALCULATION OF FISH BIOACCUMULATION FACTORS

Paul Bradley, Karen Riva Murray, Barbara C. Scudder Eikenberry, 

Christopher D. Knightes, Celeste A. Journey, Mark A. Brigham1

Mercury (Hg) bioaccumulation factors (BAFs; ratios of Hg in fish [Hgfish] and water 

[Hgwater]) are used to develop Total Maximum Daily Load and water quality criteria for 

Hg-impaired waters. Protection of wildlife and human health depends directly on the accuracy 

of site-specific estimates of Hgfish and Hgwater and the predictability of the relation between 

these parameters. BAF variability can be viewed as resulting from two conceptual drivers: 

1) ecological variability (signal) due to ecosystem-specific differences in Hg uptake and 

accumulation and 2) methodological variability (noise). Thus, minimizing methodological 

variability in Hgfish (numerator) and Hgwater (denominator) estimates is critical to BAFbased Hg risk management.

Data collected by fixed protocol from 11 streams in 5 states distributed across the US were 

used to assess the effects of Hgfish normalization/standardization methods and fish sample 

numbers on BAF numerator estimates. Fish length, followed by weight, was most correlated 

to adult top-predator Hgfish. Site-specific BAFs based on length-normalized and standardized 

Hgfish estimates demonstrated up to 50 percent less variability than those based on nonnormalized Hgfish. Permutation analysis indicated that length-normalized and standardized 

Hgfish estimates based on at least 8 trout or 5 bass resulted in mean Hgfish coefficients of 

variation less than 20 percent.

The influences of water sample timing, filtration, and mercury species on the modeled relation 

between game fish and water mercury concentrations were evaluated across the same 11 sites, 

in order to identify optimum Hgwater sampling approaches for BAF denominator estimation. 

Each model included fish trophic position, to account for a wide range of species collected 

among sites, and flow-weighted Hgwater estimates. Models based on methylmercury (filtered 

[FMeHg] or unfiltered) performed better than total mercury models. Models including mean 

annual FMeHg were superior to those with mean FMeHg calculated over shorter time periods 

throughout the year. FMeHg models including metrics of high concentrations (80th percentile 

and above) observed during the year performed better, in general. These higher concentrations 

occurred most often during the growing season at all sites.

1

Paul Bradley, Hydrologist, US Geological Survey, Columbia, SC 29210

Karen Riva Murray, Ecologist, US Geological Survey, Troy, NY 12180

Barbara C. Scudder Eikenberry, Hydrologist, US Geological Survey, Middleton, WI 53562

Christopher, D. Knightes, Environmental Engineer, US Environmental Protection Agency, Athens, GA 30605

Celeste A. Journey, US Geological Survey, Columbia, SC 29210

Mark A. Brigham, Hydrologist, US Geological Survey, Mounds View, MN 55112
74 Headwaters to Estuaries: Advances in Watershed Science and Management

Mercury Fate, Transport, and Bioaccumulation in Wetland Influenced Ecosystems: Field Studies and Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

SIMULATING MERCURY AND METHYL MERCURY 

STREAM CONCENTRATIONS AT MULTIPLE SCALES IN A 

WETLAND INFLUENCED COASTAL PLAIN WATERSHED 

(McTIER CREEK, SC, USA)

Chris Knightes, G.M. Davis, H.E. Golden, P.A. Conrads, P.M. Bradley, C.A. Journey1

Mercury (Hg) is the toxicant responsible for the most fish advisories across the United States, 

with 1.1 million river miles under advisory. The processes governing fate, transport, and 

transformation of mercury in streams and rivers are not well understood, in large part, because 

these systems are intimately linked with their surrounding watersheds and are often highly 

spatially variable. In this study, we apply a linked watershed hydrology and biogeochemical 

cycling (N, C, and Hg) model (VELMA, Visualizing Ecosystems for Land Management 

Assessment) to simulate daily flow, fluxes, and soil and stream concentrations of total mercury 

(THg) and methyl mercury (MeHg) at multiple spatial scales in McTier Creek within the 

Edisto River basin. The Edisto River basin is in the Coastal Plain of South Carolina, USA, 

and is characterized by low stream-gradients and extensive riparian wetlands with some of 

the highest top predator fish tissue Hg concentrations in the USA. By linking hydrology with 

N, C, and Hg cycling, the VELMA model can capture the importance of hydrology in linking 

watershed and wetland Hg to the stream Hg concentrations as well as the importance of 

dissolved organic carbon in transport. In this study, we (1) used field study data to calibrate 

and simulate Hg fate and transport processes at a reach scale (0.1 km2), (2) applied this 

calibrated parameter set at larger watershed scales including two headwater sub-watersheds 

(28 km2 and 25 km2) nested within the McTier Creek watershed (79 km2), and (3) evaluated 

how accurate the reach-scale parameters and processes are when scaled up to larger scales. 

The results of the VELMA multi-scale simulations suggest that water column stream THg 

concentration predictions matched observations reasonably well at different scales using 

reach-scale calibrations, but the model simulations of MeHg stream concentrations at 

reach, sub-watershed, and watershed pour points are out-of-phase with observed MeHg 

concentrations. This result suggests that processes governing MeHg loading to the main 

channel may not be fully represented in the current model structure and underscores the 

complexity of simulating MeHg dynamics in watershed models as well as the need for a 

better understanding of processes governing methylation and MeHg transport. This work 

demonstrates the importance of hydrology in understanding Hg fate in watersheds and streams 

and the influence of out-of-channel versus in-channel processes.

1

Chris Knightes, Enviornmental Engineer, US Enviornmental Protection Agency, Athens, GA 30605

G.M. Davis, Enviornmental Engineer, US Environmental Protection Agency, Office of Research and Development, Ecosystems Research Division, 

Athens, GA 30605

H.E. Golden, Research Physical Scientist, US Environmental Protection Agency, Office of Research and Development, Ecological Exposure Research 

Division, Cincinnati, OH 45268

P.A. Conrads, Hydrologist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29210

P.M Bradley, Hydrologist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29210 

C.A. Journey, Water Quality Specialist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29210
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 75

Mercury Fate, Transport, and Bioaccumulation in Wetland Influenced Ecosystems: Field Studies and Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

SCALING UP WATERSHED MODEL PARAMETERS—

FLOW AND LOAD SIMULATIONS OF THE EDISTO RIVER BASIN

Toby Feaster, Stephen Benedict, Jimmy Clark, Paul Bradley, Paul Conrads1

The Edisto River is the longest and largest river system completely contained in South 

Carolina and is one of the longest free flowing blackwater rivers in the United States. The 

Edisto River basin also has fish-tissue mercury concentrations that are among the highest 

recorded in the United States. As part of an ongoing effort by the U.S. Geological Survey 

to expand the understanding of relations among hydrologic, geochemical, and ecological 

processes that affect fish-tissue mercury concentrations within the Edisto River basin, 

analyses and simulations of the hydrology of the Edisto River basin were made using 

the topography-based hydrological model (TOPMODEL). The potential for scaling up a 

previous application of TOPMODEL for the McTier Creek watershed, which is a small 

headwater catchment to the Edisto River basin, was assessed. Scaling up was done in a stepwise process beginning with applying the calibration parameters, meteorological data, and 

topographic wetness index data from the McTier Creek TOPMODEL to the Edisto River 

TOPMODEL. Additional changes were made with subsequent simulations culminating in 

the best simulation, which included meteorological and topographic wetness index data from 

the Edisto River basin and updated calibration parameters for some of the TOPMODEL 

calibration parameters. Comparison of goodness-of-fit statistics between measured and 

simulated daily mean streamflow for the two models showed that with calibration, the Edisto 

River TOPMODEL produced slightly better results than the McTier Creek model, despite the 

significant difference in the drainage-area size at the outlet locations for the two models (30.7 

and 2,725 square miles, respectively). Along with the TOPMODEL hydrologic simulations, 

a visualization tool (the Edisto River Data Viewer) was developed to help assess trends and 

influencing variables in the stream ecosystem. Incorporated into the visualization tool were 

the water-quality load models TOPLOAD, TOPLOAD-H, and LOADEST. Because the 

focus of this investigation was on scaling up the models from McTier Creek, water-quality 

concentrations that were previously collected in the McTier Creek basin were used in the 

water-quality load models.

1

Toby Feaster, Hydrologist, US Geological Survey, Clemson, SC 29631

Stephen Benedict, Hydrologist, US Geological Survey, Clemson, SC 29631

Jimmy Clark, Hydrologist, US Geological Survey, Columbia, SC 29210

Paul Bradley, Hydrologist, US Geological Survey, Columbia, SC 29210

Paul Conrads, Surface Water Specialist, US Geological Survey, Columbia, SC 29210
76 Headwaters to Estuaries: Advances in Watershed Science and Management

Mercury Fate, Transport, and Bioaccumulation in Wetland Influenced Ecosystems: Field Studies and Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

EVALUATION OF MERCURY LOADS FROM 

CLIMATE CHANGE PROJECTIONS

Paul Conrads, Paul M. Bradley, Stephen T. Benedict, Toby D. Feaster1

McTier Creek is a small coastal plain watershed located in Aiken County, South Carolina. 

McTier Creek forms part of the headwaters for the Edisto River basin, which is noted 

for having some of the highest recorded fish-tissue mercury concentrations in the United 

States. A simple water-quality load model, TOPLOAD, which was developed for McTier 

Creek, utilizes a mass balance equation in conjunction with hydrologic simulations from 

the topography-based hydrological model - TOPMODEL. TOPLOAD is an effective tool 

for analyzing the relative flux contribution of the simulated surface and groundwater flow 

paths in TOPMODEL. Climate models for the Southeastern United States project increased 

temperatures across the region but also project differing precipitation results with some 

models indicating an increase in precipitation and some, a decrease. Climate models for the 

Southeast generally agree that the frequency and durations of droughts are likely to increase 

due to the higher temperature and resulting increases in evapotranspiration. To evaluate effect 

of projected climate change on flow paths for McTier Creek due to changes in hydrology, 

downscaled data from two global circulation models (GCM) for one emission scenario were 

used as inputs to TOPLOAD. One GCM, the Community Climate System Model (CCSM), 

projects an increase in total precipitation whereas the other GCM, ECHO (a hybrid of the 

European Center atmospheric GCM [ECHAM] and the Hamburg Primitive equation ocean 

GCM [HOPE]), projects no significant change in total precipitation. Both models project 

changes in precipitation intensity and duration. The relative changes in the total mercury 

flux contributions for the flow paths in TOPLOAD for each GCM and the management 

implications will be given in this presentation.

1

Paul Conrads, Surface Water Specialist, US Geological Survey, Columbia, SC 29210

Paul Bradley, Hydrologist, US Geological Survey, Columbia, SC 29210

Stephen T. Benedict, Hydrologist, US Geological Survey, Clemson, SC 29631

Toby Feaster, Hydrologist, US Geological Survey, Clemson, SC 29631
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 77

Mercury Fate, Transport, and Bioaccumulation in Wetland Influenced Ecosystems: Field Studies and Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

CLIMATE CHANGE AND WATERSHED MERCURY EXPORT IN A 

COASTAL PLAIN WATERSHED

Heather Golden, Christopher D. Knightes, Paul A. Conrads, Toby D. Feaster, 

Gary M. Davis, Stephen T. Benedict, Paul M. Bradley1

Future changes in climatic conditions may affect variations in watershed processes (e.g., 

hydrological, biogeochemical) and surface water quality across a wide range of physiographic 

provinces, ecosystems, and spatial scales. How such climatic shifts will impact watershed 

mercury (Hg) dynamics and hydrologically-driven Hg transport is a significant concern. 

We apply an ensemble of watershed models to simulate watershed hydrological and total 

Hg (HgT) fluxes from the landscape to the watershed outlet (i.e., HgT export) and water 

column HgT concentrations in response to a set of statistically-downscaled climate change 

projections in a Coastal Plain watershed. Three watershed models are used to quantify and 

bracket potential changes in hydrologic and HgT export, including the Visualizing Ecosystems 

for Land Management Assessment Model for Hg (VELMA-Hg), the Grid Based Mercury 

Model (GBMM), and TOPLOAD, a water quality constituent model linked to TOPMODEL 

hydrological simulations. Based on downscaled estimates from two global circulation models 

(i.e., ECHO, which represents dry future conditions for the region, and CCSM3, which 

reflects wet future conditions) we estimate a 19 percent decrease in average annual watershed 

HgT export in response to climate change using the ECHO projections and a 5 percent 

increase with the CCSM3 projections in the study watershed. Average monthly watershed 

HgT export increases using both climate change projections in the late spring (March through 

May), when HgT concentrations and streamflow are high. Results suggest that hydrological 

transport associated with changes in precipitation and temperature is the primary mechanism 

driving HgT export response to climate change. Our ensemble watershed model approach 

highlights the uncertainty associated with projecting climate change responses – both 

hydrologically and biogeochemically – and the use of such projections in future watershed 

management and planning efforts.

1

Heather Golden, Research Physical Scientist, US Enviornmental Protection Agency, Office of Research & Development, National Exposure Research 

Laboratory, Cincinnati, OH 45268

Christopher D. Knightes, Environmental Engineer, US.Enviornmental Protection Agency, Office of Research & Development, National Exposure 

Research Laboratory, Athens, GA 30605

Paul A. Conrads, Surface Water Specialist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29210

Toby D. Feaster, Hydrologist, US Geological Survey, South Carolina Water Science Center, Clemson, SC 29631

Gary M. Davis, Enviornmental Engineer, US Enviornmental Protection Agency, Office of Research & Development, National Exposure Research 

Laboratory, Athens, GA 30303

Stephen T. Benedict, Hydrologist, US Geological Survey, South Carolina Water Science Center, Clemson, SC 29631

Paul M. Bradley, Hydrologist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29210

Water Quality

(PART 1)
80 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Quality (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE USE OF ACOUSTIC DOPPLER METERS TO ESTIMATE 

SEDIMENT AND NUTRIENT CONCENTRATIONS IN FRESHWATER 

INFLOWS TO TEXAS COASTAL ECOSYSTEMS

Zulimar Lucena, Michael Lee1

Excessive sediment and nutrient loading are among the leading causes of impairment in 

water bodies of the United States due to their effect on biologic productivity, water quality, 

and aquatic food webs. Understanding the nutrient and suspended sediment loads affecting 

estuarine waters is fundamental to the assessment of the physical, chemical, and biological 

processes governing the aquatic system and essential for establishing watershed management 

strategies. The need to effectively estimate sediment and nutrient loads into coastal 

ecosystems and reservoirs highlights the importance of developing methods for monitoring 

these constituents. One technique to determine suspended sediment concentrations involves 

the use of acoustic Doppler meters. The acoustic Doppler meters are primarily used to 

measure water velocity using the Doppler principle, but also output a return pulse strength 

indicator called backscatter. These backscatter data can serve as an explanatory variable for 

developing regression model estimates of sediment and nutrients when related to discrete 

measurements of these constituents collected over the discharge range of the river. In this 

manner, the backscatter signal from these instruments may serve as a surrogate for these 

constituents in some environments and provide a continuous estimate of in situ concentrations. 

In Texas, the U.S. Geologic Survey, in cooperation with the Texas Water Development 

Board and the Galveston Bay Estuary Program, have installed acoustic Doppler meters on 

the lower reaches of the Trinity River going into Trinity Bay, on the Guadalupe River going 

into San Antonio Bay, and the Colorado River going into Matagorda Bay. Surrogate models 

between backscatter and nutrient and suspended sediment concentrations are being evaluated 

in these systems. The Surrogate Analysis and Index Developer Tool (SAID), developed by 

the USGS, is being used to process acoustic parameters as predictor variables of sediment 

and nutrient concentrations and assist in the creation of regression models while providing 

visual and quantitative diagnostics. These models can enhance our limited understanding 

of inflow contributions to the coastal waters of Texas, particularly during high flow periods 

when substantial pulses of sediment and nutrients have the potential of affecting the aquatic 

ecosystem. Improved methods for determining freshwater inflow contributions of discharge, 

sediment, and nutrients may be useful for inclusion in hydrodynamic and water quality 

models and may help fill a data gap of the volume of freshwater inflow entering Texas 

coastal ecosystems.

1

Zulimar Lucena, Hydrologist, US Geological Survey, Shenandoah, TX 77385

Michael Lee, Supervisory Hydrologist, US Geological Survey, Shenandoah, TX 77385
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 81

Water Quality (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

FUSING LONG-TERM, HISTORICAL, AND HIGH-RESOLUTION 

DATA TO INFORM ESTIMATES OF WATERSHED-SCALE 

NITROGEN RETENTION

Jonathan Duncan, Lawrence Band1

Closing watershed nitrogen budgets is difficult because inputs typically far exceed outputs. A 

leading hypothesis to explain this discrepancy is that retention is poorly constrained because 

a disproportionate amount of denitrification occurs in small portions of the landscape (hot 

spots) during brief hydrologic conditions (hot moments). Many measurement and modeling 

frameworks under-sample denitrification and transport associated with these hot spots and 

hot moments. Significant progress in closing a watershed nitrogen budget requires combining 

a suite of sensors to capture spatial and temporal heterogeneity of nitrogen dynamics. Longterm weekly sampling of stream chemistry at Pond Branch, MD USA, a 37 ha forested 

watershed in the Piedmont physiographic province, has revealed recurrent summer peaks in 

nitrate concentrations and loads. A high-frequency in-stream in situ nitrate sensor has revealed 

that concentration-discharge dynamics of diel and storm events are different from those 

calculated using weekly data. Statistical calculations of nitrogen export and concentrationdischarge analyses yield important insights into biological vs. hydrologic mechanisms of 

retention. Resolving denitrification in soils requires mapping spatial heterogeneity with 

high-resolution topographic data derived from LiDAR. A combination of soil oxygen probes 

and soil core measurements is required to estimate denitrification from watershed soils. 

Riparian microtopography in Pond Branch has been shown to be an important control in 

watershed scale denitrification. Enhanced consideration of the hydrogeomorphic template 

of watersheds to predict the location and importance of biogeochemical hotspots ultimately 

requires understanding their genesis. In Pond Branch, a fuller understanding of historical land 

use change and the corresponding geomorphic changes is important to help constrain our 

interpretation of landscape form and biogeochemical function. Fusing long-term, historical, 

and spatiotemporal sensor data is required for moving towards closing the watershed 

nitrogen budget.

1

Jonathan Duncan, Postdoctoral Research Associate, University of North Carolina Chapel Hill, Chapel Hill, NC 27312

Lawrence Band, Professor, University of North Carolina Chapel Hill, Chapel Hill, NC 27312
82 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Quality (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

COMPARING NUTRIENT EXPORT FROM FIRST, SECOND, 

AND THIRD ORDER WATERSHEDS IN THE SOUTH CAROLINA 

ATLANTIC COASTAL PLAIN

Augustine Muwamba, Devendra M. Amatya, Carl C. Trettin, and James B. Glover1

Abstract—Monitoring of stream water chemistry in forested watersheds provides information to environmental 

scientists that relate management operations to hydrologic and biogeochemical processes. We used data for the first order 

watershed, WS80, and second order watershed, WS79, at Santee Experimental Forest. We also used data from a third order 

watershed, WS78, to identify the differences in temporal changes of stream water chemistry from 2006 to 2012. Phosphate 

concentrations for WS80 and WS79 decreased from 2006 to 2012. Most of the nitrogen (N) component was dominated 

by organic N and the watershed that registered highest organic N also registered highest total N concentration. Phosphate 

and N concentrations for all watersheds varied with rainfall received in the area. The annual mean pH of all watersheds 

significantly increased with stream conductivity (p < 0.05). The differences in fluctuations of observed annual stream water 

nutrient concentrations for all watersheds may provide a basis for nutrient availability for aquatic responses. 

INTRODUCTION

The stream water chemistry at Santee Experimental 

Forest in South Carolina is routinely monitored for 

environmental assessment records, and data can be used 

by researchers to identify potential impacts of burning, 

land uses, and weather changes on water quality. Richter 

and others (1983) reported that most of the nitrogen (N) 

for Santee Forest is in organic form and that phosphate 

and potassium (K) concentrations were mostly from soil 

derived particulates for data collected from 1976 to 1979. 

Wilson and others (2006) also reported higher organic N 

than inorganic N when analyzing data for the periods of 

1976-1981 and 1989-1994. The organic N concentration 

contributed most to total nitrogen (TN) of Turkey Creek 

(third order watershed) for 2006-2008 (Amatya and 

others 2009). Amatya and others (2009) also reported an 

inverse relationship between dissolved oxygen and stream 

temperature for Turkey Creek. Ammonium nitrogen and 

phosphate concentrations decreased with flow and the 

greatest portion of stream water TN concentration was 

organic N for the two first order watersheds in Coastal 

North Carolina (Amatya and others 2006, 2007). Lu 

and others (2005) also documented that variation in 

flow and rainfall lead to variation in stream nutrient 

concentrations. Other factors that can lead to variation 

in stream water chemistry of watersheds are seasonal 

temperature variation, spatial and temporal variations of 

land use, vegetation cover and silivicultural management 

practices (Lu and others 2005). The fact that fertilizers 

are not applied to Santee Experimental Forest, nutrient 

concentrations are hypothesized to decrease with plant 

age due to increasing plant uptake and fluctuate with 

flow. Therefore, studying the temporal changes of N 

components (NH4-N, NO3-N, TKN, organic N, and 

inorganic N) and phosphorus (P) within each watershed 

and among watersheds is very important for nutrient 

availability and stream water quality assessment. 

The data reported were collected from three watersheds: a 

first order watershed (WS 80),  a second order watershed 

(WS79), and a third order watershed (WS78) of drainage 

areas of 160 ha, 500 ha, and 5,240 ha, respectively.  WS79 

is comprised of two first order watersheds, the relatively 

undisturbed (WS80) as a control and a treatment (WS77) 

that is subjected to prescribed burning, and a small 

area in between. The objective was to compare N and 

P concentrations among the first order (WS80), second 

order (WS79), and third order (WS78) watersheds for 

a period of 2006-2012. Other physical and chemical 

parameters compared were stream temperature, pH, 

specific conductance, and dissolved oxygen (DO) 

concentration.

1

Augustine Muwamba, Postdoctoral Researcher, University of Georgia, Athens, GA 30602

Devendra Amatya,Research Hydrologist, USDA Forest Service, Center for Forested Wetlands Research, Cordesville, SC 29434

Carl Trettin, Research Soil Scientist, USDA Forest Service, Center for Forested Wetlands Research, Cordesville, SC 29434

James Glover, Manager, Aquatic Biology Section, SCDHEC Bureau of Water, Columbia, SC 29201
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 83

Water Quality (Part 1)

MATERIALS AND METHODS

First (WS80), Second (WS79), and Third (WS78) 

Order Watersheds

The site for the watersheds is located in the South 

Carolina coastal plain (33.15° N and 79.8° W). 

Established in 1968, WS80 is a mosaic of upland (70 

percent) and wetland (30 percent) forests with an area 

of 160 ha and drains the first order streams to Turkey 

Creek. Soils for WS80 are classified as somewhat 

poorly to poorly drained (SCS 1980). Loblolly pine and 

hardwoods currently predominate WS 80. The elevations 

range from 4 to 6 m with 0 to 3 percent slope for WS80. 

The weather parameters reported by Harder and others 

(2007) included a mean annual temperature of 18.30C and 

average annual precipitation of 1370 mm. Other authors 

have documented the site’s hydrologic changes and water 

quality (Sun and others 2000, Amatya and others 2003, 

2006, 2007). WS79 (mosaic upland (75 percent) and 

wetland (25 percent) forests) is a second order watershed 

with a drainage area of 500 ha formed by streams from 

two first order watersheds, WS80 (160 ha) and WS77 (155 

ha). WS77 is dominated by loblolly pine and subjected 

to prescribed burning. The third order watershed, WS78 

is a mosaic upland (90 percent) and wetland (10 percent) 

forest, and has a drainage area of 5240 ha. The elevation 

of WS78 ranges from 3.6 m at the stream gauging station 

to 14 m above mean sea level. WS78 soils consist of 

poorly drained soils of Wahee (clayey, mixed, thermic 

Aeric Ochraquults) and Lenoir (clayey, mixed, Thermic 

Aeric Paleaquults) series (SCS 1980) and small areas of 

somewhat poorly and moderately well drained sandy and 

loamy soils. The greatest land use within the watershed 

is loblolly pine (Pinus taeda L.) and long leaf pine 

(Pinus palustris) forest. Other land uses of WS78 include 

forested wetland and hardwood and crop lands, roads and 

open areas (Amatya and others 2009). Details, uses and 

weather parameters measured at WS78 were documented 

by Amatya and others (2009). Figure 1 shows the location 

map for WS80, WS79, and WS78. Other details of the 

watersheds are posted on the website, http://cybergis.

uncc.edu/santee/waterQualityPage.php.

Water Quality Monitoring and Analysis

Grab samples were collected weekly, or more frequently 

depending upon the storm size, and analyzed for N 

(NH4-N, NO3-N, and total N) and P (in the form of 

phosphate) from 2006 to 2012. Amatya and others (2007) 

described the details of water quality monitoring and 

analysis. Bottles with samples preserved were frozen until 

the sample analysis at the Soil Chemistry Laboratory in 

Charleston, South Carolina. The parameters of stream 

temperature, pH, specific conductance, and dissolved 

oxygen (DO) concentration were also determined as a 

function of time. Water samples at the watershed outlets 

were collected using an ISCO 3700 sampler. Ammonium 

nitrogen in water was analyzed by QuikChem© Method, 

Flow Injection Analysis Calorimetry. Nitrate-nitrite was 

determined by the QuikChem© Method 10-107-04-1, 

Flow Injection Analysis. Total N was determined by 

Figure 1—Location map of watersheds WS80, WS79, and WS78 (from Amatya and others 2015).
84 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Quality (Part 1)

QuikChem© Method 10-107-04-3-B, In-Line Digestion 

Followed by Flow Injection Analysis). The detection 

limits for NH4-N, NO3-N, and total N were all 0.01 mg 

L-1. Dissolved inorganic nitrogen (DIN) was calculated 

as a sum of NH4-N and NO3-N, and DON was calculated 

as total N minus DIN. Phosphate was determined by 

Micro-membrane Suppressed Ion Chromatography. 

Details of water quality monitoring and analysis are also 

posted on the website, http://cybergis.uncc.edu/santee/

waterQualityPage.php, under metadata.

RESULTS AND DISCUSSION

Temporal Changes of pH, Stream Conductivity, 

Dissolved Oxygen, and Temperature

Table 1 shows the annual mean and ranges for pH, stream 

conductivity, dissolved oxygen, and temperature. The 

annual mean pH followed the trend WS80>WS78>WS79 

except for 2008 and 2010. WS80 registered the highest 

conductivity compared to WS79 and WS78 from 2006 

to 2012. WS78 recorded the highest DO concentration 

from 2006-2012; the DO concentration trend was WS78 

> WS80 > WS79. There were no significant differences 

in stream temperatures between watersheds (p > 0.05). A 

positive correlation between annual mean pH and stream 

conductivity (p < 0.05) for all watersheds was recorded. 

Annual mean stream conductivity of WS79 and WS78 

significantly increased with stream temperature (p < 0.05). 

Annual mean dissolved oxygen significantly increased 

with a decrease in temperature for WS78 (p < 0.05).

We found an inverse relationship of DO concentrations 

with the water temperature for 2006 to 2008, with high 

values during the cold winter (maximum of 14.3 mg 

L-1 in January 2007) and lower values (lowest of 1.36 

mg L-1 in June 2006) during the hot summer months, 

with an average of 6.1 mg L-1 for WS78 (Amatya and 

others 2009). The pH levels and DO concentrations for 

watersheds were partly attributed to natural conditions 

and swamp conditions by Lebo and others (2000). The 

interactions of parameters could be attributed to varying 

sizes of the watersheds, seasonal variations in flows and 

rainfall, variation in land uses, and vegetation growth 

patterns (Lu and others 2005).

Temporal Changes of Nitrogen and Phosphorus

Figures 2 to 7 show changes of annual mean N and 

phosphate concentrations from 2006 to 2012 for all 

watersheds. The decreasing concentration trend with 

increased rain was more pronounced with phosphate 

than N. The annual rain received in the area was 1264, 

1041, 1521, 1458, 1380, 959, and 1117 mm in 2006, 

2007, 2008, 2009, 2010, 2011, and 2012, respectively. 

For all watersheds, organic N was higher than inorganic N 

(Fig. 4 and 5). The watersheds that registered highest 

organic N also registered highest total N (Fig. 5 and 

6). Except for 2006 and 2010, total N was highest 

for WS80 than WS78 and WS79. Watersheds 80 and 

WS78 registered a systematic decrease in phosphate 

concentrations from 2008 to 2012 unlike WS79. 

Ammonium nitrogen concentrations for WS78 were 

higher than NO3-N from 2006 to 2012. Ammonium 

nitrogen, NO3-N, total N, and phosphate maximum 

concentrations (mg L-1) for WS80 were 1.07, 0.16, 

2.05, and 0.58, respectively for the period 2006 to 2012. 

For WS79, the maximum NH4-N, NO3-N, total N, and 

phosphate concentrations (mg L-1) recorded were 1.47, 

0.05, 2.80, and 0.07, respectively. The maximum NH4-N, 

NO3-N, total N, and phosphate concentrations (mg L-1) 

recorded for WS78 were 0.33, 0.23, 1.93, and 0.30, 

Table 1—Annual mean of physical and chemical parameters for WS80, WS79, and WS78 with ranges in parentheses

2006 2007 2008 2009 2010 2011 2012

pH

WS80 6.7(5.8-8.8) 7.8(6.9-8.4) 8.5(8.1-9.5) 6.0(5.5-6.3) 6.4(5.9-7.2) 6.0(5.3-6.2) 5.9(4.8-6.4)

WS79 6.4(5.5-7.5) 7.5(6.1-8.3) 8.0(7.4-8.6) NA 6.2(5.6-7.1) 5.7(5.5-6.2) 5.7(4.9-6.2)

WS78 6.6(5.8-7.3) 7.6(5.7-8.8) 6.9(5.4-8.7) NA 6.0(5.0-7.7) 5.9(4.9-6.4) 5.8(4.9-6.6)

Conduct. 

(microS/

cm)

WS80 0.2(0.1-0.5) 0.3(0.1-0.5) 0.2(0. 1-0.4) 0.1(0.07-0.2) 0.10(0.06-0.2) 0.1(0.06-0.2) 0.12(0.07-0.2)

WS79 0.2(0.1-0.3) 0.2(0.1-0.3) 0.16(0.1-0.2) NA 0.08(0.06-0.1) 0.08(0.06-0.1) 0.07(0.06-0.1)

WS78 0.2(0.1-0.4) 0.2(0.1-0.3) 0.1(0.01-0.3) NA 0.05(0.01-0.1) 0.08(0.05-0.1) 0.08(0.07-0.1)

DO 

(mg L-1)

WS80 3.3(0.4-8.8) 4.4(1.6-11.2) 4.5(2.0-7.8) 3.5(0.8-8.1) 4.6(2.0-8.8) 3.2(1.2-6.3) 4.2(1.4-7.9)

WS79 2.9(0.3-8.8) 3.9(0.9-12.4) 5.8(1.7-10.0) NA 4.6(1.4-10.2) 2.5(0.7-7.7) 2.8 (1.0-5.9)

WS78 5.1(1.4-11) 5.7(1.4-14.3) 6.7(1.6-12.0) NA 7.5(1.6-12.9) 4.5(0.9-8.8) 4.9(0.9-11.2)

Temp. (0C)

WS80 20(6.4-29) 18.4(5.8-30.2) 13.4(6.0-21.0) 11.7(7.4-14.3) 13.7(4.4-27.2) 18.6(8.1-27.7) 17.0(4.7-26.1)

WS79 20(6.6-27) 18(5.6-29.7) 12.9(4.8-20.5) NA 13.6(4.8-26.7) 16.8(5.5-27.3) 16.6(5.1-25.7)

WS78 20(6.8-28) 18.6(5.6-29.6) 17.8(4.6-26.2) NA 12.3(3.7-27.3) 19.5(8.8-27.7) 16.7(4.4-26.8)

DO = Dissolved oxygen, Conduct. = Stream conductivity, Temp. = Temperature, NA = Data not available
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 85

Water Quality (Part 1)

respectively. The NO3-N concentrations for all watersheds 

from 2006 to 2012 did not exceed drinking water standard 

value, 10 mg L-1, reported by USEPA (2000). 

Nitrogen and phosphate concentrations varied with rain 

received with years receiving highest rainfall registering 

lower concentrations, and this was attributed to dilution 

effects. The dilution effects due to increasing flow 

volumes on nutrients have been reported by Lynch and 

Corbett (1990). Differences in flush effects after dry 

periods of the year could also lead to variability within 

and between annual mean nutrient concentrations. 

Elevated nutrient concentrations soon after long dry 

periods were associated with flush effects (Amatya 

and others 1998, 2009). The systematic decrease in 

inorganic N and phosphate from 2006 to 2012 for WS80 

was attributed to increased uptake since the site was 

undisturbed. The annual mean phosphate concentrations 

for WS80 were greater than WS79 concentrations 

probably due to lower flow for WS80 than WS79. Since 

WS77 and WS80 drain to form WS79, and WS77 has 

been reported to register higher flow than WS80 (Amatya 

and others 2006, 2007) due to greater slope and periodic 

prescribed burning that reduces vegetation cover on 

WS77, greater organic N and phosphate concentrations 

were recorded for WS80. Plants might have preferred 

inorganic N than organic N and since no inorganic 

fertilizers were applied to WS80, greater organic N than 

inorganic N was recorded for the watersheds. Amatya and 

others (2009) also reported higher NH4-N concentration 

than NO3-N for WS78 when analyzing data for the period, 

2006 to 2008. Wilson and others (2006) also reported 

Figure 3—Annual mean nitrate nitrogen concentration as a function of time for a first order (WS80), second order 

(WS79), and third order watershed (WS78). Bars represent standard deviations of the mean.

Figure 3. 

Figure 2—Annual mean ammonium nitrogen concentration as a function of time for a first order (WS80), second 

order (WS79), and third order watershed (WS78). Bars represent standard deviations of the mean.
86 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Quality (Part 1)

1

Figure 4. 

Figure 5. 

Figure 6. 

Figure 4—Annual mean dissolved inorganic nitrogen concentration as a function of time for a first order (WS80), 

second order (WS79), and third order watershed (WS78). 

Figure 5—Annual mean dissolved organic nitrogen concentration as a function of time for a first order (WS80), 

second order (WS79), and third order watershed (WS78)

Figure 6—Annual mean total nitrogen concentration as a function of time for a first order (WS80), second order 

(WS79), and third order watershed (WS78). Bars represent standard deviations of the mean.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 87

Water Quality (Part 1)

greater organic N than inorganic N with historical data. 

Other probable reasons for variabilities in nutrient 

concentrations among watersheds could be differences in 

watershed drainage areas, land uses, vegetation types, and 

plant uptake. For example, Lu and others (2005) reported 

that small scale watersheds have greater heterogeneity 

than large scale watersheds.

CONCLUSIONS

Variations in N and P concentrations and pH, DO, 

conductivity, and stream temperature from 2006 to 2012 

for all watersheds were likely influenced by rainfall 

received, differences in plant nutrient uptake, constituents 

(vegetation type and cover), differences in land uses, 

and watershed areas. The dominant N component for 

all watersheds was organic N and the watershed that 

had the highest DON also registered the highest total N. 

Phosphate concentration showed a systematic decreasing 

trend from 2006 to 2012 for WS80 and WS78. 

ACKNOWLEDGMENTS

We extend our appreciation to USDA Forest Service 

Southern Research Station for providing data and funds 

that facilitated the project.

LITERATURE CITED

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10-year of eco-hydrologic studies on Turkey Creek Watersed 

(this volume).In: Stringer, C.E., Krauss, K.W., and Latimer, 

J.S., eds. Proceedings of the Fifth Interagency Conference on 

Research on Watersheds, Trident Technical College, North 

Charleston, SC, March 2-5, 2015.

Amatya, D.M.; Callahan, T.J; Trettin, C.C.; Radecki-Pawlik, A. 

2009. Hydrologic and water quality monitoring on Turkey 

Creek Watershed, Francis Marion National Forest, SC. 

ASABE paper No. 09-5999. June 21-24, Annual ASABE 

International Meeting, Reno, NV.

Amatya, D.; Harrison, C.; Trettin, C.C. 2007. Water quality of 

two first order forested watersheds in coastal South Carolina.

ASABE Publication Number 701P0207. Proceedings of the 

Fourth Conference, March 10-14, San Antonio, Texas USA.

Amatya, D.M.; Miwa, M.; Harrison, C.A.; Trettin, C.C.; Sun, G. 

2006. Hydrology and water quality of two first order forested 

watersheds in coastal South Carolina. Paper No. 06-2182, St. 

Joseph, MI: ASABE, 22 p.

Amatya, D.M.; Sun, G.; Trettin, C.C.; Skaggs, R.W. 2003. 

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Carolina. In: Renard, K. G., McElroy, S.A., Gburek, W.J., 

Canfield, H.E, and Scott, R.L., eds. Proceedings of the First 

Interagency Conference on Research in the Watersheds. 2003 

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Service: 279-285.

Amatya, D.M.; Gilliam, J.W.; Skaggs, R.W.; Lebo, M.E.; 

Campbell, R.G. 1998. Effects of controlled drainage on forest 

water quality. Journal of Environmental Quality 27:923-935.

Harder, S.V.; Amatya, D.M.; Callahan, T.J.; Trettin, C.C.; 

Hakkila, J. 2007. Hydrology and water budget of a forested 

coastal plain watershed. Journal of the American Water 

Resources Association. 43(3): 563-575.

1

Figure 7. 

Figure 7—Annual mean phosphate concentration as a function of time for a first order (WS80), second order 

(WS79), and third order watershed (WS78). Bars represent standard deviations of the mean.
88 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Quality (Part 1)

Lebo, M.E.; Fromm, J.H.; McHenry, D. 2000. Evaluation of the 

condition of Kendricks Creek, North Carolina. Environment, 

Health and Safety Weyerhaeuser Company, New Bern, North 

Carolina. June 2000.

Lu S.; Amatya, D.M.; Miller, J. 2005. Development of 

watershed and reference loads for a TMDL in Charleston 

Harbor System, SC. ASABE Publication Number 701P0105. 

Proceedings of the Third Conference 5-9 March. Atlanta, 

GA USA.

Lynch, J.A.; Corbett, E.S. 1990. Evaluation of best management 

practices for controlling nonpoint pollution from 

silivicultural operations. Journal of the American Water 

Resources Association. 26(1): 41-52.

QuickChem© (1) Method 10-107-06-1-I, Determination 

of Ammonia (Phenolate) by Flow Injection Analysis 

Colorimetry, Lachat Instruments, 5600 Lindburgh Drive, 

Loveland, Colorado, 80539, USA

QuickChem© (2) Method 10-107-06-1-A, Determination of 

Nitrate/Nitrite in Surface and Wastewaters by Flow Injection 

Analysis . Lachat Instruments, 5600 Lindburgh Drive, 

Loveland, Colorado, 80539, USA

QuikChem© (4) Method 10-107-04-3-B, Determination of Total 

Nitrogen in Waters in-Line Digestion Followed By Flow 

Injection Analysis. Lachat Instruments, 5600 Lindburgh 

Drive, Loveland, Colorado, 80539, USA

Sun, G.; Lu, J.; Gartner, D.; Miwa, M.; Trettin, C.C. 2000. 

Water budgets of two forested watersheds in South Carolina. 

In: Proceedings of the Spring Special Conference of the 

American Water Resources Association, 2000.

Richter, D.D.; Ralston, C.W.; Harms, W.R. 1983. Chemical 

composition and spatial variation of bulk precipitation at a 

coastal plain watershed in South Carolina. Water Resources 

Research. 19:134-140.

Soil Conservation Service (SCS). 1980. Soil survey of 

Berkeley County, South Carolina. U.S. Department of 

Agriculture, 94 p.

US EPA. 2000. National water quality inventory: 1998. Report 

to Congress at http://www.epa.gov/owowwtr1/305b/98report/

index.html.

Wilson, L.; Amatya, D.M.; Callahan, T.J.; Trettin, C.C. 2006. 

Hurricane impact on stream flow and nutrient exports for a 

first-order forested watershed of the Lower Coastal Plain, 

South Carolina. In: Proceedings of the Second Interagency 

Conference on Research on Watersheds, Coweeta Hydrologic 

Laboratory, Otto, NC, May 16-18, 2006.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 89

Water Quality (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

QUANTIFYING IN-STREAM NITRATE REACTION RATES USING 

CONTINUOUSLY-COLLECTED WATER QUALITY DATA

Matthew Miller, Anthony Tesoriero, Paul Capel1

High frequency in situ nitrate data from three streams of varying hydrologic condition, land 

use, and watershed size were used to quantify the mass loading of nitrate to streams from 

two sources – groundwater discharge and event flow – at a daily time step for one year. These 

estimated loadings were used to quantify temporally-variable in-stream nitrate processing 

rates. Nitrate in groundwater discharge was identified as contributing approximately 70 

percent of the total nitrate load to a large river and small agricultural stream, compared with 

45 percent to a small urban stream. The greatest in-stream losses of nitrate occurred during 

the summer and fall months, with net in-stream losses of up to 70 percent of total nitrate load 

in the large river, 60 percent in the agricultural stream, and 50 percent in the urban stream. 

Stream discharge and nitrate concentrations were inversely correlated with nitrate loss rates; 

whereas temperature and photosynthetically active radiation were positively correlated with 

loss. This study demonstrates a new approach for interpreting high frequency nitrate data that 

may be applied in other stream ecosystems to quantify temporal variability in nitrate source 

loading and rates of in-stream processing. These source and rate estimates can in turn be used 

to improve predictive models of nitrate transport and potentially inform efforts to reduce 

nutrient loads to streams and coastal environments.

1

Matthew Miller, Research Hydrologist, US Geological Survey, Salt Lake City, UT 84119

Anthony Tesoriero, Research Hydrologist, US Geological Survey, Oregon Water Science Center, Portland, OR 97201 

Paul Capel, Physical Scientist, US Geological Survey, NAWQA Program, Minneapolis, MN 55455
90 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Quality (Part 1)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

A WATERSHED-SCALE CHARACTERIZATION OF 

DISSOLVED ORGANIC CARBON AND NUTRIENTS 

ON THE SOUTH CAROLINA COASTAL PLAIN

Daniel Tufford, Setsen Altan-Ochir1

Dissolved organic matter (DOM) is recognized as a major component in the global carbon 

cycle and is an important driver of numerous biogeochemical processes in aquatic ecosystems, 

both in-stream and downstream in estuaries. This study sought to characterize chromophoric 

DOM (CDOM), dissolved organic carbon (DOC), and dissolved nutrients in major rivers 

and their tributaries of the South Carolina Coastal Plain to assess the impact of land cover, 

soils, and other factors on water quality. During eight trips from June 11 to July 9 of 2014 

throughout the South Carolina Coastal Plain, we visited 54 sites, where we measured field 

parameters (temperature, dissolved oxygen, pH, and specific conductance) and collected 

water samples for laboratory analysis of DOM ultraviolet absorbance and concentrations of 

DOC and dissolved nutrient. Sample sites included headwater wetlands and springs, streams 

and rivers, and water table monitoring wells. Spectral analysis of the filtered water samples 

was done from 200-800 nm using a Shimadzu UV-1700 spectrophotometer. We calculated 

absorption coefficients, spectral slope coefficients, and related metrics to facilitate broad 

characterizations of the nature of the CDOM in the water based on source and other landscape 

factors. We performed principle components analysis (PCA) to further understand variability 

in the data from a landscape perspective. The highest concentrations of CDOM occurred in 

black waters and in smaller streams and rivers. There were significant differences in spectral 

ratios, DOC concentration, and pH among the different water types and stream orders. PCA 

showed that DOC in black water is strongly associated with the occurrence of wetlands. 

Land cover associations were more variable in brown and clear water. DOC concentration in 

blackwater streams was higher in the lower Coastal Plain than in the upper Coastal Plain. This 

presentation will discuss these and other results of dissolved nutrient analysis and the context 

within the understanding of Coastal Plain ecological linkages with coastal estuaries.

1

Daniel Tufford, Research Associate Professor, University of South Carolina, Columbia, SC 29208

Setsen Altan-Ochir, Rodgers Fellow in Enviornmental Studies, Department of Geology, Cornell College, Mount Vernon, IA 52314
Water Responses to 

Management and Restoration
92 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Responses to Management and Restoration

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

EVALUATING HYDROLOGICAL RESPONSE OF FUTURE LAND COVER 

CHANGE SCENARIOS IN THE SAN PEDRO RIVER (U.S./MEXICO) WITH 

THE AUTOMATED GEOSPATIAL WATERSHED ASSESSMENT 

(AGWA) TOOL

William G. Kepner, I. Shea Burns, David C. Goodrich, D. Phillip Guertin, 

Gabriel S. Sidman, Lainie R. Levick, Wilson W.S. Yee, Melissa M.A. Scianni, 

Clifton S. Meek, Jared B. Vollmer1

Abstract—Long-term land-use and land cover change and their associated impacts pose critical challenges to sustaining 

vital hydrological ecosystem services for future generations. In this study, a methodology was developed to characterize 

potential hydrologic impacts from future urban growth through time. Future growth is represented by housing density 

maps generated in decadal intervals from 2010 to 2100, produced by the U.S. Environmental Protection Agency (EPA) 

Integrated Climate and Land-Use Scenarios (ICLUS) database. ICLUS developed future housing density maps by adapting 

the Intergovernmental Panel on Climate Change (IPCC) social, economic, and demographic storylines to the conterminous 

United States. To characterize hydrologic impacts from future growth, the housing density maps were reclassified to 

National Land Cover Database 2006 land cover classes and used to parameterize the Soil and Water Assessment Tool 

(SWAT) using the Automated Geospatial Watershed Assessment (AGWA) modeling system.

INTRODUCTION

Scenario analysis provides the capability to explore 

pathways of change that diverge from baseline conditions 

and lead to plausible future states or events. Scenario 

analysis has been used in studies related to environmental 

decision support to assist in evaluating policy or 

management options, such as in the Colorado River Basin 

(USDI 2012). Most approaches are designed to analyze 

alternative futures related to decision options, potential 

impacts and benefits, long-term risks, and management 

opportunities (Steinitz and others 2003, Kepner and 

others 2012, March and others 2012). The technique 

provides a dynamic and flexible way to evaluate policy 

or management options and is frequently combined with 

process modeling intended to bridge the gap between 

science and decision making across a broad range of 

spatial and temporal scales (Liu and others 2008a and 

2008b, Mahmoud and others 2009). 

The objective of this study is to develop and demonstrate 

a methodology to integrate a widely used watershed 

modeling tool with an internally consistent national 

database of alternative futures which can then be scaled 

to regional watershed applications. The focus of the study 

is to explore cumulative impacts of housing densities 

parsed out at decadal intervals to the year 2100 on a 

hydrological ecosystem consisting primarily of ephemeral 

and intermittent waters.

Ephemeral waters are extremely important in the arid 

west as a key source of groundwater recharge (Goodrich 

and others 2004). They provide important near channel 

alluvial aquifer recharge to support aquatic ecosystems 

in downstream perennial and intermittent streams (Baille 

and others 2007) and also provide critical ecosystem 

services (Levick and others 2008). Based on the National 

Hydrography Dataset; 94, 89, 88, and 79 percent of the 

1

William G. Kepner, Research Ecologist, U.S. Environmental Protection Agency, Office of Research and Development, Las Vegas, NV 89119

I. Shea Burns, Senior Research Specialist, University of Arizona, School of Natural Resources and the Environment, Tucson, AZ 85721 

David C. Goodrich, Research Hydraulic Engineer, USDA-Agricultural Research Service, Southwest Watershed Research Center, Tucson, AZ 85719

D. Phillip Guertin, Professor, University of Arizona, School of Natural Resources and the Environment, Tucson, AZ 85721

Gabriel S. Sidman, GIS/Remote Sensing Analyst, Winrock International, Arlington, VA 22202

Lainie R. Levick, Principal Research Specialist, University of Arizona, School of Natural Resources and the Environment, Tucson, AZ 85721

Wilson W. S. Yee, Life Scientist, U.S. Environmental Protection Agency, Region 9, San Francisco, CA 94105

Melissa M. Scianni, Life Scientist, U.S. Environmental Protection Agency, Region 9, San Francisco, CA 94105

Clifton S. Meek, Life Scientist, U.S. Environmental Protection Agency, Region 9, San Francisco, CA 94105

Jared B. Vollmer, Environmental Protection Specialist, U.S. Environmental Protection Agency, Region 9, San Francisco, CA 94105
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 93

Water Responses to Management and Restoration

streams in Arizona, Nevada, New Mexico, and Utah, 

respectively, are intermittent or ephemeral (Alexander and 

others 2015).

For the purpose of this study, the results are restricted to 

the San Pedro River, U.S./Mexico (Fig. 1). The intent is 

to quantitatively evaluate hydrologic impacts of future 

developments at the basin scale, which intrinsically 

addresses the cumulative impact of multiple housing 

development projects. The study area encompasses the 

Arizona portion of the watershed (9,800 km2). The San 

Pedro River flows 230 km from its headwaters in Sonora, 

Mexico to its confluence with the Gila River near the 

stream gage (USGS 09473500) at Winkelman, AZ. It is 

nationally known as one of the last free-flowing rivers 

in the Southwest. It has significant ecological value, 

supporting one of the highest numbers of mammal species 

in the world and providing crucial habitat and a migration 

corridor to several hundred bird species. Vegetation ranges 

from primarily semi-desert grassland and Chihuahuan 

desert scrub in the Upper San Pedro to primarily Sonoran 

desert scrub and semi-desert grassland in the Lower San 

Pedro. The Upper San Pedro is home to the San Pedro 

Riparian National Conservation Area (SPRNCA). It was 

designated as the first National Conservation Area for 

riparian protection by Congress in 1988. The SPRNCA 

protects approximately 64 km of river and is administered 

by the U.S. Department of the Interior, Bureau of Land 

Management (Kepner and others 2004, Bagstad and 

others 2012).

METHODS

The Automated Geospatial Watershed Assessment 

(AGWA; Miller and others 2007; http://www2.epa.

gov/water-research/automated-geospatial-watershedassessment-tool and http://www.tucson.ars.ag.gov/agwa) 

tool is the key hydrological modeling system utilized 

in this study to identify areas that are most sensitive to 

environmental degradation as well as areas of potential 

Figure 1—Location Map of the Study Area Contrasting the Extent of the ICLUS Data Used in the Future Scenarios 

to the San Pedro Watershed.
94 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Responses to Management and Restoration

mitigation or enhancement opportunities, and thus inform 

restoration, permitting, and water management strategies. 

AGWA is recognized as one of the world’s primary 

watershed modeling systems (Daniel and others 2011) 

providing the utility to generate hydrologic responses at 

the subwatershed scale and spatially visualize results for 

qualitative comparisons. 

The AGWA tool was used to model the San Pedro 

Watershed with the SWAT model. The AGWA tool is a 

user interface and framework that couples two watershedscale hydrologic models, the KINematic Runoff and 

EROSion model (KINEROS2; Semmens and others 2008) 

and the Soil and Water Assessment Tool (Arnold and 

others 1994), within a geographic information system 

(GIS). The coupling of hydrologic models and GIS 

within the AGWA tool performs model parameterization, 

execution, and watershed assessment at multiple temporal 

and spatial scales, and visualization of model simulation 

results. Current outputs generated through use of the 

AGWA tool are runoff (volumes and peaks) and sediment 

yield, plus nitrogen and phosphorus with the SWAT 

model. Simulations were parameterized using a 10m 

digital elevation model (DEM) and derived flow direction 

and accumulation, modified State Soil Geographic 

(STATSGO) soils, seven precipitation stations, and the 10 

land cover datasets produced by combining the National 

Land Cover Database/North American Landscape 

Characterization Project (NLCD/NALC) digital land 

cover datasets with the decadal ICLUS datasets.

 The approach is a multi-step process. First, the watershed 

border is defined to ensure that data are obtained for the 

entire study area. Digital land cover data is converted 

into a format compatible with AGWA and reflecting the 

available scenario options into the future. Next, soils 

and precipitation data for the study area are located 

and extracted. Finally, AGWA is used to delineate 

subwatersheds as comparative units and parameterize 

and run the Soil and Water Assessment Tool (Neitsch 

and others 2002; Srinivasan and Arnold 1994) for the 

baseline condition and future land cover/use scenarios. 

The Integrated Climate and Land-Use Scenarios (ICLUS; 

Bierwagen and others 2010; EPA, 2009; EPA, 2010) 

project data were identified as an ideal dataset for 

projecting basin-wide development into the future. The 

ICLUS national-scale housing-density (HD) scenarios are 

consistent with the Intergovernmental Panel on Climate 

Change (IPCC 2001) Special Report on Emissions 

Scenarios (SRES; Nakicenovic and Swart 2000) 

greenhouse gas emissions storylines and they are available 

in 10-year increments until 2100.

To define the project extent, the project watershed is 

delineated in AGWA and given a buffer distance of 500 

meters. The watershed is delineated using a 10-meter 

DEM that has been hydrologically corrected to ensure 

proper surface water drainage. In the United States (and 

for basins extending into Mexico), the U.S. Geological 

Survey’s (USGS) The National Map Viewer and 

Download Platform (http://nationalmap.gov) provides 

the National Elevation Dataset (NED; http://ned.usgs.

gov/) source data. The digital land cover available for 

this study is derived from two sources. The National 

Land Cover Database 2006 (Fry and others 2011) was 

used in combination with the North American Landscape 

Characterization Project (EPA, 1993) to capture classified 

digital land cover of known accuracy (Kepner and others 

2000, Kepner and others 2003, Skirvin and others 2004).

Because the 2006 NLCD and 1992 NALC datasets 

have different classifications, the NALC land cover 

was reclassified to match the NLCD land cover. The 

reclassified NALC dataset of Mexico is then combined 

with the 2006 NLCD dataset of the U.S. resulting in 

a derived NLCD dataset that covers the entire project 

extent. The ICLUS HD data is combined with the NLCD/

NALC data to project future development by decade to 

2100. The ICLUS data have five categories of housing 

density representing rural, exurban, suburban, urban, and 

commercial/industrial.

The ICLUS database produced 5 seamless, national-scale 

change scenarios for urban and residential development. 

The A2 Scenario is characterized by a high fertility 

rate (average number of children that would be born to 

a woman over her lifetime) and low net international 

migration; it represents the highest U.S. population 

scenario gain (690 million people by 2100). The Base 

Case (BC) and Scenario B2 are the middle scenarios, with 

a medium fertility rate and medium to low international 

migration. Differences between BC and B2, as well as 

A1 and B1, reflect how housing is allocated – sprawl vs. 

compact growth patterns. As a result of this distinction, 

the county populations in urban and suburban areas 

generally grow faster than in rural areas in the base 

case, but the experiences of individual counties vary. A1 

and B1, with low fertility rates and high international 

migration are the lowest of the population scenarios. 

The primary difference between these scenarios occurs 

at the domestic migration level, with an assumption of 

high domestic migration under A1 and low domestic 

migration under B1. The effect of different migration 

assumptions becomes evident in the spatial model when 

the population is allocated into housing units across the 

landscape. The national Baseline forecast for 2100 is 

450M people and B1 could be lower at 380M people. The 

A2 Scenario results in the largest changes in urban and 

suburban housing density classes and greater conversion 

of natural land-cover classes into new population 

centers, or urban sprawl. The largest shift from suburban 

densities to urban occurs in 2050 – 2100 for the A-family 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 95

Water Responses to Management and Restoration

scenarios (Bierwagen and others 2010). The ICLUS 

scenarios were developed using a demographic model 

to estimate future populations through the year 2100 

and then allocated to 1-hectare pixels by county for the 

conterminous U.S. (EPA 2009, EPA 2010). The final data 

sets provide decadal projections of both housing density 

and impervious surface cover from the 2000 baseline year 

projected out to the year 2100.

The NLCD data has different land cover classes, a 

different projection, and is at a different resolution (30m) 

than the ICLUS data (100m); therefore the ICLUS data 

were pre-processed for use in this project. Preprocessing 

includes clipping the ICLUS data to the boundary of 

Arizona, projecting the ICLUS data to UTM Zone 12 

NAD83, reclassifying the ICLUS data to NLCD classes 

and resampling the ICLUS data from 100m to 30m. The 

resulting dataset was then merged with the NLCD dataset 

so the ICLUS data replaced the NLCD data if there 

was a change in land cover. The reclassification scheme 

was determined based on housing density definitions, 

which were different between the two datasets. As a 

result the “Rural” land cover type in the ICLUS data was 

defaulted to the NLCD class present at that location. This 

methodology was incorporated into a tool in ArcToolbox 

in ArcGIS for easy conversion of the ICLUS datasets.

In this example, only Scenario A2 (corresponding to 

storyline A2 in the SRES) of the ICLUS data was used 

for example analysis, however all five ICLUS scenarios 

(A1, A2, B1, B2, and BC) were used in the final analysis 

(Burns and others 2013). Ten land cover datasets per 

scenario (50 total) are produced from the combination 

of the NLCD/NALC datasets and the ICLUS datasets, 

representing the change in landscape attributed to 

population and development changes by decade from 

2010 to 2100. For each scenario, the dataset from 2010 

is used as the project baseline to which the successive 

decadal datasets are compared. Soils data for the U.S. 

were obtained from the Natural Resources Conservation 

Service (NRCS) - National Cartography and Geospatial 

Center’s (NCGC) State Soil Geographic (STATSGO; 

USDA-NRCS 1994) database. Soils data for Mexico were 

obtained from the San Pedro Data Browser (Kepner and 

others 2003, Boykin and others 2012). The soil types were 

matched and redefined to equivalent STATSGO soil types. 

Precipitation data obtained from the National Climatic 

Data Center (NCDC; http://www.ncdc.noaa.gov/) were 

used to drive the SWAT model in AGWA. Climate stations 

within or near the San Pedro Watershed were reviewed 

for periods of record and completeness of the dataset. 

The review produced a total of seven climate stations in 

Arizona with the recorded precipitation needed for the 

SWAT model (Fig. 1). The period of record is from 1971-

2001.

RESULTS

All scenarios resulted in an increase to the Human Use 

Index (HUI) metric averaged over the entire watershed. 

HUI (adapted from Ebert and Wade, 2004) is the percent 

area in use by humans. It includes NLCD land cover 

classes “Developed, Open Space”; “Developed, Low 

Intensity”; “Developed, Medium Intensity”; “Developed, 

High Intensity”; “Pasture/Hay”; and “Cultivated Crops”. 

The ICLUS A2 Scenario resulted in the largest increase of 

the HUI, 2.21percent in year 2100 for the entire watershed 

(Fig. 2 and Table 1).

Similarly to the increases in HUI over the entire 

watershed, both simulated runoff and sediment yield 

increased at the watershed outlet over time for all 

scenarios; Scenario A2 experienced the largest percent 

change in surface runoff and sediment yield, 1.04 and 

1.19 percent, respectively (Figures 3 and 4; Tables 2 

and 3). Percent change was calculated using the following 

equation:

([decadei]-[basei])

[basei

]

x 100

 

(1)

where [decadei] represents simulation results for a decade 

from 2020 through 2100 for a given scenario (i) and 

[basei] represents the baseline 2010 decade for the same 

scenario.

Figure 5 depicts the percent change of HUI, channel 

sediment yield, and subwatershed surface runoff from 

2010 to 2100 for Scenario A2. The changes in HUI relate 

well to the changes in sediment yield and surface runoff. 

The figures show the impact of growth locally on one 

level with the subwatersheds and in greater detail with the 

explicit percent change in the growth areas.

DISCUSSION

Hydrologic impacts of future growth through time were 

evaluated by using reclassified ICLUS housing density 

data by decade from 2010 to 2100 to represent land cover 

in AGWA. AGWA is a GIS tool initially developed to 

investigate the impacts of land cover change to hydrologic 

response at the watershed scale to help identify vulnerable 

regions and evaluate the impacts of management. AGWA 

allows for assessment of basin-wide changes and 

cumulative effects at the watershed outlet as well as 

more localized changes at the subwatershed level.

ICLUS datasets were used for a number of reasons 

including their availability (http://cfpub.epa.gov/ncea/

global/recordisplay.cfm?deid=205305). Reclassification 

was necessary to convert from housing density classes 
96 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Responses to Management and Restoration

Figure 4—Watershed Average Percent Change in Sediment Yield for All Scenarios.

Figure 2—Watershed Average Human Use Index (HUI) for All Scenarios.

Figure 3—Watershed Average Percent Change in Surface Runoff for All Scenarios.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 97

Water Responses to Management and Restoration

Table 1—Change in Human Use Index for All Scenarios (2010 - 2100)

HUI 

Base Change in Human Use Index from base

2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

Scenario A1 5.23% 0.36% 0.57% 0.69% 0.76% 0.79% 0.81% 0.83% 0.84% 0.85%

Scenario A2 5.09% 0.41% 0.66% 0.88% 1.10% 1.33% 1.54% 1.73% 1.95% 2.21%

Scenario B1 5.15% 0.22% 0.33% 0.39% 0.41% 0.42% 0.43% 0.43% 0.43% 0.43%

Scenario B2 5.09% 0.23% 0.37% 0.47% 0.52% 0.55% 0.58% 0.61% 0.66% 0.73%

Baseline BC 5.12% 0.34% 0.57% 0.74% 0.89% 1.04% 1.19% 1.33% 1.44% 1.54%

Table 2—Change in Surface Runoff for All Scenarios (2010 - 2100).

Surface

Runoff Base Percent Change in Surface Runoff from Base

2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

Scenario A1 42.98 mm 0.15% 0.23% 0.29% 0.33% 0.34% 0.36% 0.37% 0.38% 0.39%

Scenario A2 42.95 mm 0.17% 0.29% 0.38% 0.47% 0.59% 0.70% 0.80% 0.91% 1.04%

Scenario B1 42.96 mm 0.08% 0.13% 0.16% 0.18% 0.19% 0.19% 0.20% 0.20% 0.20%

Scenario B2 42.96 mm 0.08% 0.14% 0.19% 0.21% 0.24% 0.26% 0.29% 0.34% 0.38%

Baseline BC 42.96 mm 0.13% 0.24% 0.32% 0.38% 0.45% 0.52% 0.59% 0.65% 0.71%

Table 3—Change in Channel Sediment Yield for All Scenarios (2010 - 2100). 

Sediment

Yield Base Percent Change in Sediment Yield from Base

2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

Scenario A1 25220 t 0.16% 0.24% 0.36% 0.40% 0.40% 0.44% 0.48% 0.48% 0.52%

Scenario A2 25200 t 0.24% 0.32% 0.44% 0.56% 0.60% 0.75% 0.91% 0.95% 1.19%

Scenario B1 25210 t 0.12% 0.12% 0.16% 0.20% 0.20% 0.20% 0.20% 0.20% 0.20%

Scenario B2 25200 t 0.12% 0.20% 0.20% 0.24% 0.24% 0.28% 0.32% 0.36% 0.44%

Baseline BC 25200 t 0.16% 0.24% 0.36% 0.44% 0.52% 0.60% 0.60% 0.67% 0.79%
98 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Responses to Management and Restoration

to “developed” type classes in the 2006 National Land 

Cover Database. All land cover classes of the NLCD 

are supported in AGWA via look-up tables which allow 

for translation of land cover classes into hydrologic 

parameters necessary to parameterize the hydrologic 

models.

The results produced by the AGWA-SWAT modeling 

represent a qualitative assessment of anticipated 

hydrologic change resulting from the ICLUS A1, A2, B1, 

B2, and BC scenarios. Historic rainfall and climate data 

are used to drive the SWAT model, so anticipated climate 

change is not accounted for in the results, although 

climate change may amplify or reduce the results 

presented here. Quantitative assessments of anticipated 

hydrologic impacts resulting from the ICLUS scenarios 

would require calibration for the baseline (2010) for 

each scenario and additional information to parameterize 

future decades, including but not limited to the design and 

placement of flood mitigation measures (detention basins, 

riparian buffers, water harvesting, recharge wells, open 

space infiltration galleries, etc.) that would be a required 

component of any future development.

The methodology presented herein uses HUI as an 

easily quantifiable metric for land cover change resulting 

from urban growth; however it does not distinguish 

between different types of human use. Different types of 

human use, ranging from “Developed, Open Space” to 

“Developed, High Intensity” to “Cultivated Crops” have 

different hydrologic properties associated with them, 

so despite the observed relationship between increasing 

HUI and increasing surface runoff and sediment yield in 

the results, HUI cannot be used as a surrogate for actual 

hydrologic modeling, which more closely captures the 

actual land cover properties and the complex interactions 

and feedbacks that occur across a watershed.

The greatest changes in surface runoff occur in 

subwatersheds where the change in HUI was also greatest; 

accordingly, the smallest changes in surface runoff occur 

in areas where the change in HUI was smallest. Sediment 

Figure 5—Change in Human Use Index (HUI), Sediment Yield, and Surface Runoff (both Average and Explicit) 

in Percent from 2010 to 2100 for Scenario A2.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 99

Water Responses to Management and Restoration

yield in the channels is largely driven by surface runoff, so 

channels immediately downstream of subwatersheds with 

high changes in HUI and surface runoff experience the 

largest changes in sediment yield. The results emphasize 

the importance of investigating localized impacts to 

natural resources at appropriate scales as the impacts at 

the subwatershed scale and below can be much greater 

than at the basin scale. They also highlight the effective 

modulation of local changes by large undevelopable 

areas. At the subwatershed scale, unacceptable hydrologic 

impacts may be observed that would not otherwise 

be captured at the basin scale if development was 

occurring basin-wide. Instead, basin-wide impacts are 

effectively averaged out by undevelopable lands. Thus 

any interests in cumulative effect should be addressed 

at the subwatershed versus basin scale for this western 

watershed or others like it which contain large tracts of 

land in the public domain, and are therefore not subject to 

direct urbanization impacts.

CONCLUSIONS

Changes in land cover/use under the A2 Scenario result in 

the greatest hydrologic impacts due to a higher population 

growth rate and a larger natural land cover conversion 

rate. The results of the analyses for all scenarios over the 

2010 – 2100 year period (Tables 2 and 3) indicate changes 

in the range of 0.2 percent (B1 Scenario) to 1.04 percent 

(A2 Scenario) on average surface runoff across the 

watershed, and changes in the range of 0.2 percent (B1 

Scenario) to 1.19 percent (A2 Scenario) on sediment yield 

at the watershed outlet.

Local changes to hydrology and sediment delivery at 

the subwatershed level and below are relevant because 

at those scales the impacts tend to be much more 

significant. Additionally, since the hydrologic impacts 

are tied to changes in land cover, and because the San 

Pedro Watershed has large amounts of land that cannot 

be developed, the hydrologic impacts at a watershed 

scale are expected to be limited. The localized impact of 

development found in this study may be representative 

for much of the western arid and semi-arid U.S., where 

47.3 percent of the 11 coterminous western states (AZ, 

CA, CO, ID, MT, NV, NM, OR, UT, WA, and WY) is 

managed as federal public lands by the Bureau of Land 

Management, Fish and Wildlife Service, National Park 

Service, U.S. Forest Service and the Department of 

Defense (Gorte and others 2012). Despite the constraints 

that limit developable areas, hydrologic changes at the 

watershed scale are still expected to occur.

Simulated increases in percent change of surface runoff 

and sediment yield closely tracked increases in the HUI 

metric; consequently growth and development should be 

moderated to prevent large increases in surface runoff 

and sediment yield, which could degrade water quality 

from sediment and pollutant transport, erode and alter 

the stream channel, degrade or destroy habitat, decrease 

biological diversity, and increase flooding. The effects of 

growth may be magnified or mitigated by climate change, 

though this is not accounted for in this analysis.

Scenario analysis is an important framework to help 

understand and predict potential impacts caused by 

decisions regarding conservation and development. For 

the EPA and other stakeholders, hydrologic modeling 

systems (e.g. AGWA) integrated with internally-consistent 

national scenario spatial data (i.e. ICLUS) provide an 

important set of tools that can help inform land use 

planning and permitting, mitigation, restoration, and water 

management strategies.

ACKNOWLEDGMENTS

This study was funded through the U.S. Environmental 

Protection Agency Regional Applied Research Effort 

Program, which is administered by the Office of Research 

and Development’s (ORD) Regional Science Program. 

It has been subjected to both the EPA/ORD and USDA/

Agricultural Research Service peer and administrative 

review processes and has been approved for publication. 

The Automated Geospatial Watershed Assessment tool 

was jointly developed by EPA/ORD, USDA/ARS, and the 

University of Arizona. The Integrated Climate and Land 

Use Scenarios database was developed by EPA/ORD. 

AGWA and ICLUS are endorsed and recommended by 

each of the respective agencies, especially in regard to 

their integrated use. 

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102 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Responses to Management and Restoration

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ECOHYDROLOGY OF A FLOODPLAIN FOREST: 

RELATIONSHIPS BETWEEN VEGETATION AND GROUNDWATER 

RESOURCES AT CONGAREE NATIONAL PARK, 

SOUTH CAROLINA USA

Timothy Callahan, Lauren Senn1

The goal of this project was to investigate the relationship between the shallow, 

unconfined aquifer and woody vegetation at eight sites of the Congaree Observation Well 

Network at Congaree National Park near Hopkins, South Carolina. Eight piezometers 

with screens of 1.5-m length (top-of-screen depths ranging from 3.0 to 5.0 m below 

ground surface) along a 1.8-km cross-valley transect from the foot of a fluvial terrace 

and terminating near Cedar Creek in the national park. Time series data of groundwater 

level and temperature have been collected with automated data loggers in the piezometers 

since 2009. Groundwater response to storm event data from a nearby weather station was 

used to approximate specific yield of the sub-soils and sediments of the aquifer. White’s 

Method was used to analyze diurnal ET signals for select periods during 2009-2012. 

Vegetation surveys focused on woody shrub and canopy species growing within a 400 

m2 plot centered on each well. Metrics included basal area index (BAI), biodiversity, and 

relative abundance. Gross ET estimates ranged from 0.2 to 10 mm per day, depending on 

season. Vegetation composition was typical of floodplain forest associations as previously 

described for the site; however, ET and BAI were not correlated. Alternative explanations 

include the following: 1) local topographic changes in the form of hummocks and 

hollows may influence groundwater flow; 2) hydrostratigraphic variation may influence 

the ET signal more than the local vegetation; 3) the effects of local vegetation can only 

be measured with larger plots. Qualitative analysis of LIDAR elevation data collected 

along the piezometer transect suggest there may be some relation between hummocks 

(small hills) and vegetation, but more refined data are needed to quantify this association. 

We will present extrapolated estimates of ET across the entire floodplain portion of the 

park and discuss the uncertainties of such data. The details of groundwater dynamics are 

not well understood in the Congaree River Valley, and neither are the relative scale of 

evapotranspiration (ET) in the water budget and our intention is provide baseline data for 

future research, along with information that could help develop management guides for 

flood control and predictions in these types of watersheds.

1

Timothy Callahan, Associate Professor, College of Charleston, Charleston, SC 29424

Lauren Senn, Student, Graduate Program in Environmental Studies, College of Charleston, Charleston, SC 29424
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 103

Water Responses to Management and Restoration

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

RELATIONSHIPS BETWEEN WILDLAND FIRES AND 

WATERSHED HYDROLOGY ACROSS THE CONTIGUOUS U.S.

Dennis W. Hallema, Ge Sun, Peter V. Caldwell, Steven P. Norman, 

Erika C. Cohen, Yongqiang Liu, Steven G. McNulty1

Wildland fires contribute to the natural succession in forested watersheds by stimulating 

growth and biodiversity. Notwithstanding, these fires present an increasing hazard at the 

wildland-urban interface, and cover large areas as a result of the high fire severity associated 

with forest densification. Fire severity and intensity determine to a large degree the total burnt 

area and loss of leaf area (LAI), however our knowledge of the impact on hydrology is far 

from complete. Loss of LAI and interception can increase runoff and sediment loads threefold 

or more, and is considered a first-order effect of fire. A study involving an Arizona ponderosa 

pine forest shows that infiltration rates decrease by up to 62 percent on a severely burnt soil, 

and may cause higher peak flow (e.g. 201-290 percent) and accelerated erosion as a result 

of reduced soil wettability. Simulations with the WaSSI water balance model suggest that a 

reduction of LAI by 50 percent can lead to a significant increase in water yield (e.g. >17-93 

mm/yr, or 7-21 percent in wet regions with annual precipitation >800 mm and 3-32 mm/

yr, or 10-20 percent in regions with 300-800 mm of precipitation). Forested watersheds are 

important sources of water supply, and stakeholders are becoming increasingly aware of the 

potential effects of wildland fire on these water supplies and the occurrence of flash floods 

causing severe damage to property and infrastructure. Nevertheless, there are many ways to 

mitigate excessive runoff due to fire, such as pre-fire management, Burned Area Emergency 

Response, and recent studies recommend a total ground cover of at least 60 percent with straw 

mulch, which reduces runoff and sediment yields during at least one year following a wildland 

fire, however the effect of combinations of fuel management at different scales (local, 

regional) remains uncertain. In this contribution we present an overview of the advances in 

scientific literature on the relationship between wildland fires and watershed hydrology across 

the contiguous United States, and aim to identify new avenues for research that can enhance 

the resilience of forest ecosystems and assist decision making with regard to prescribed fuel 

treatments. This research was supported in part by an appointment to the USFS. Research 

Participation Program administered by the ORISE through an interagency agreement 

between DOE and the USFS. All opinions expressed in this work are the author’s and do not 

necessarily reflect the policies and views of USDA, DOE, or ORAU/ORISE.

1

Dennis W. Hallema, USDA Forest Service, Southern Research Station, Raleigh, NC 27606

Ge Sun, Research Plant Physiologist, USDA Forest Service, Southern Research Station, Raleigh, NC 27606 

Peter, V. Caldwell, Research Hydrologist, USDA Forest Service, Southern Research Station, Otto, NC 28763

Steven P. Norman, Research Ecologist, USDA Forest Service, Southern Research Station, Asheville, NC 28804

Erika C. Cohen, USDA Forest Service, Southern Research Station, Raleigh, NC 27606

Yongquiang Liu, Research Meteorologist, USDA Forest Service, Southern Research Station, Athens, GA 30602

Steven G. McNulty, Supervisory Ecologist, USDA Forest Service, Southern Research Station, Raleigh, NC 27606
104 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Responses to Management and Restoration

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

RIPARIAN AREA HARVESTING IMPACTS ON VEGETATION 

COMPOSITION AND DIVERSITY

Katherine Elliot, James M. Vose1

In the southern Appalachians USA, the boundaries of riparian areas are often hard to define. 

Vegetation is often used as a riparian indicator and plays a key role in protecting water 

resources, but adequate knowledge of floristic responses to riparian disturbances is lacking. 

Our objective was to quantify floristic composition and diversity of the riparian communities 

before (2004) and one, two, and seven years after harvest treatments with varying buffer 

widths. The treatments were harvest distances of 0 m, 10 m, and 30 m away from the stream 

edge. Sites were harvested between 2005 and 2006. The harvest method for all treatments 

was a heavy selection cut followed by a highlead, cable-yarding leaving a low residual basal 

area (ca. 5.0 m2/ha) within the harvested zone. We examined: (1) differences among sites 

using a mixed linear model with repeated measures (SAS 9.4); (2) multivariate relationships 

among ground-layer species composition and environmental variables (soil water content, 

light transmittance, tree basal area, shrub density, and distance from stream) using nonmetric 

multidimensional scaling (NMS); and (3) species composition among sample years using 

a multiresponse permutation procedure (MRPP) in PC-ORD version 5. The first year 

after harvest, overstory density and basal area were reduced by 83 percent and 65 percent, 

respectively, for the 0-m buffer site; reduced by 50 percent and 74 percent for the 10-m 

buffer site; and reduced by 45 percent and 29 percent for the 30-m buffer site. After 7 years, 

however, both the 0-m and 10-m buffer sites had nearly three times greater density than before 

the harvest treatments, whereas density in the 30-m buffer site was similar to its pretreatment 

condition. Basal area remained significantly lower on all harvested sites over time compared 

to the reference. Ground-layer species composition differed significantly overtime for the 

0-m buffer (MRPP; T = -5.709, A= 0.044, P < 0.0001) and 10-m buffer (MRPP; T = -5.485, 

A= 0.041, P < 0.0001), but the 30-m buffer (MRPP; T = -1.021, A= 0.008, P = 0.1510) and 

reference (MRPP; T = 1.242, A = -0.009, P = 0.9141) sites did not change after harvest 

treatments. Average Sørensen distance increased after 7 years, indicating greater within-group 

heterogeneity (species diversity) after harvesting. These vegetation recovery patterns provide 

critical information for evaluating management options in riparian zones in the southern 

Appalachians.

1

Katherine Elliot, Research Ecologist, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763 

James M. Vose, Project Leader, Center for Integrated Forest Science, Southern Research Station, USDA Forest Service, Otto, NC 28763
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 105

Water Responses to Management and Restoration

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ADVANCING STREAM RESTORATION DESIGN: 

A SCIENCE-BASED APPROACH USING DATA AND 

METHODOLOGIES FROM THE AGENCIES

Jessica Palazzolo, Joshua Robinson, Philip Ellis1

Ecosystem restoration design is a relatively new field of work that requires multi-disciplinary 

expertise in the natural sciences. Although the field is new, federal agencies and public 

institutions have spent several decades and millions of dollars researching the sciences and 

methods that underly restoration activities. However, many restoration practitioners are either 

unaware of this vast body of knowledge or simply do not know how to apply it to these new 

project types. 

This presentation will outline a science-based approach to project assessment, design, and 

construction using publicly-available data and methods from the USGS, USDA-NRCS, 

USACOE, FWS, EPA, FHWA, USBR, FEMA, interagency working groups, and peerreviewed scientific publications. Project examples located in various regions of North and 

South Carolina will be presented, including urban stream daylighting, physical restoration 

of mountainous step-pool channels, and hydrologic restoration of bidirectionally-flowing 

floodplain streams. The examples will cover information from the disciplines of hydrology, 

hydraulics, ecology, geomorphology, and civil engineering. The presentation will introduce 

various publicly-available resources, and will outline a robust framework for assessing and 

designing creek restoration projects.

1

Jessica Palazzolo, Water Resources Engineer, Robinson Design Engineers, Charleston, SC 29412 

Joshua Robinson, Civil/Enviornmental Engineer, Robinson Design Engineers, Charleston, SC 29412

Phillip Ellis, Hydraulic Engineer, Robinson Design Engineers, Charleston, SC 29412

Watershed Assessment-Tools and Data
108 Headwaters to Estuaries: Advances in Watershed Science and Management

Watershed Assessment-Tools and Data

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

MANAGING THE SPACE-TIME-LOAD CONTINUM IN TMDL PLANNING: 

A CASE STUDY FOR UNDERSTANDING GROUNDWATER LOADS 

THROUGH ADVANCED MAPPING TECHNIQUES

Phillip Harte, Marcel Belaval, Andrea Traviglia1

The lag time between groundwater recharge and discharge in a watershed and the potential 

groundwater load to streams is an important factor in forecasting responses to future land use 

practices. We call this concept managing the “space-time-load continuum.” It’s understood 

that in any given watershed, the response function (the load at any given time) will differ 

for surface runoff and groundwater discharge. The mean age of surface runoff may be days 

whereas for groundwater it could be many decades. Surface runoff reflects contemporaneous 

land use practices and relatively quick reactions whereas groundwater load reflects past land 

use practices and attenuation mechanisms in the aquifer and ephemeral zone around streams. 

The total load combines both response functions and understanding the makeup of the two 

responses can improve forecasting of future loads. 

We used advanced mapping techniques to quantify potential groundwater loads of chloride 

to a small watershed in southern New Hampshire. The small watershed is adjacent to a major 

highway corridor and the use of salt as a road deicing agent has caused increases in chloride 

concentrations in nearby Policy Brook, the subject of a chloride TMDL. Specific conductance 

in Policy Brook showed high levels (1300 μS cm-1), about five times background, during 

periods of baseflow indicating a groundwater pathway for road salt. 

Electromagnetic (EM) terrain induction conductivity surveys were conducted along Policy 

Brook to map road-salt contaminated groundwater discharge. Three different EM tools were 

used that probed slightly different depths of investigation (ranging from 0 to 12 feet below 

the streambed). Electromagnetic surveys identified several reaches of high conductivity 

groundwater. Based on the delineation of reaches, seven streambed piezometers were installed 

to sample for shallow groundwater. Correlation of shallow groundwater conductivity with EM 

allowed for the calculation of a spatially continuous mass load of chloride. Given the depth 

of EM surveys, the shallow groundwater represents a near term (months to years) potential 

groundwater load. The potential groundwater load was found to be 50 percent greater than the 

instantaneous load calculated from increases in chloride along Policy Brook during a baseflow 

period. Over the next few years, we surmise that the seasonal variability in chloride in Policy 

Brook will increase in response to the inherent seasonal variability in groundwater discharge 

and the growing divergence of surface and groundwater loads; the divergence being fueled by 

current improved practices to reduce road salt as reflected in surface runoff, and past practices 

as reflected in groundwater loads.

1

Phillip Harte, Research Hydrologist, US Geological Survey, New England Water Science Center, Pembroke, NH 03275

Marcel Belaval, Geologist, US Environmental Protection Agency, Boston, MA 02109

Andrea Traviglia, Environmental Engineer, US Environmental Protection Agency, Boston, MA 02109
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 109

Watershed Assessment-Tools and Data

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE ROLE OF WATERSHED CHARACTERISTICS IN ESTUARINE 

CONDITION: AN EMPIRICAL APPROACH

James Latimer, Melissa Hughes, Michael Charpentier, Christine Tilburg1

Estuarine condition is a function of the nature of the estuary, ocean, and atmospheric systems, 

and the upstream watershed. To fully understand and predict how an estuary will respond to 

drivers and pressures, each compartment must be characterized. For example, eutrophication 

effects on estuarine condition are generally well known; less understood is how the attributes 

of estuarine watersheds, and their spatial distributions, relate to estuarine condition. The Gulf 

of Maine Council’s Ecosystem Indicator Partnership (ESIP) and the Environmental Protection 

Agency’s (EPA) Office of Research and Development have joined for a project designed to 

link watersheds to estuarine conditions. Specifically, the goal of this research is to develop 

methods and indicators for mapping watershed integrity and aquatic condition in order to 

predict estuarine condition. The analysis uses a common set of watershed spatial indicators 

and estuarine state/impact indicators. The study builds on past work in southern New England 

using relationships between land use characteristics and aquatic habitat extent metrics (e.g., 

eelgrass) and on ESIP’s work in northern New England, which has assembled a large database 

of watershed, contaminants, climate change, aquaculture, and eutrophication variables. The 

aquatic condition data are comprised of regional data sets, including EPA’s National Coastal 

Assessment. Watersheds are being characterized using multiple indicators such as land use 

magnitude and proximity, percent impervious cover, landscape development indexes, and 

measures of terrestrial and hydrological fragmentation and connectivity. Preliminary results 

are consistent with the hypothesis that land use magnitude and proximity affect downstream 

estuarine status and impacts. The research will develop methods, models, and data on 

estuarine condition and watershed characteristics, which in turn can help justify and prioritize 

watershed protection across the United States and Canada.

1

James Latimer, Research Scientist, US Environmental Protection Agency, Narragansett, RI 02882

Melissa Hughes, Software Engineer, Raytheon Corporation, Narragansett, RI 02882

Michael Charpentier, GIS Analyst, Raytheon Corporation, Narragansett, RI 02882

Christine Tilburg, ESIP Program Manager, Gulf of Maine Council’s Ecosystem Indicator Partnership, Buxton, ME 04093
110 Headwaters to Estuaries: Advances in Watershed Science and Management

Watershed Assessment-Tools and Data

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WETLAND EXTENT AND PLANT COMMUNITY COMPOSITION 

VULNERABILITY TO CLIMATE CHANGE

Michael Nassry, Denice H. Wardrop, Anna T. Hamilton, 

Christopher J. Duffy, Jordan M. West1

The potential impact of climate change on wetland-provided ecosystem services has been 

largely unspecified because of the difficulty in predicting changing hydrologic conditions, 

which are a major driver of structure and function in these ecosystems. The Penn State 

Integrated Hydrologic Model (PIHM), constructed and calibrated using nationally available 

data sets (e.g., soils, topography, national wetlands inventory (NWI) wetlands, USGS stream 

gages), was used to generate groundwater depth conditions for multiple hydrogeomorphic 

(HGM) wetland types (depression, slope, riverine), across a range of ecoregions in 

Pennsylvania, under historical and future climate scenarios. The vulnerability of wetland 

extent to climate change was assessed based on changes in groundwater depth and changes 

in the percent of time groundwater was present in the rooting zone (upper 30 cm). These 

estimates of extent vulnerability were calculated at annual, seasonal, and growing season 

scales as well as at ecoregion, watershed, and HGM-specific spatial scales. Such scale-specific 

vulnerability assessments provide insight into the complexity of wetland sensitivities to 

changes in the hydrologic drivers of wetland structure and function and offer a surrogate for 

the estimation of which wetland-provided ecosystem services will be the most vulnerable 

to future climate change. Wetland plant community composition can also be a measure of 

wetland vulnerability and may be both more sensitive and an earlier indicator of climate 

change induced stress than wetland extent. To test this, an existing database of metrics 

characterizing the floral community (e.g., percent invasives, percent annual, floristic quality 

assessment index) and long-term hydrologic monitoring was used to develop relationships 

linking hydrology, anthropogenic disturbance, and community composition. Using the 

effects of disturbance on hydrology as a proxy for climate change, the hydrology and plant 

community relationships were extended to the modeled future hydrology scenarios to provide 

estimates of wetland plant community composition responses to climate change.

1

Michael Nassry, Research Associate, Penn State, Riparia, University Park, PA 16802

Denice H. Wardrop, Associate Director, Penn State, Riparia, University Park, PA 16802

Anna T. Hamilton, Aquatic Ecologist, Tetra Tech, Center for Ecological Sciences, Owings Mills, MD 21117

Christopher J. Duffy, Professor, Civil and Enviornmental Engineering, Penn State, PA 16802

Jordan M. West, Aquatic Ecologist, US Environmental Protection Agency, Washington, DC 20460
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 111

Watershed Assessment-Tools and Data

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

LAND COVER CHANGE IN COASTAL WATERSHEDS 

1996 TO 2010

Nate Herold1

Land use and land cover play a significant role as drivers of environmental change. 

Information on what is changing and where those changes are occurring is essential if we 

are to improve our understanding of past management practices or policies and effectively 

respond now and in the future. Through its Coastal Change Analysis Program (C-CAP), the 

National Oceanic and Atmospheric Administration (NOAA) produces nationally standardized 

land cover and change information for the coastal regions of the U.S. These products provide 

inventories of coastal intertidal areas, wetlands, and adjacent uplands (using documented, 

repeatable procedures), with the goal of monitoring these habitats every five years. This 

program has been in existence since the mid-1990s and features multiple dates of information 

available for most coastal areas of the U.S. This presentation will summarize the availability 

of this land cover and change data, how it can be accessed via NOAA’s Digital Coast, recent 

improvements to wetland mapping accuracies, summarize changes observed regionally, what 

change information is available on a watershed basis, how C-CAP can be used to inform 

management decisions or drive more detailed mapping efforts, and how this data is being used 

to model potential future impacts from sea level rise.

1

Physical Scientist, NOAA Office for Coastal Management, Charleston, SC 29405
112 Headwaters to Estuaries: Advances in Watershed Science and Management

Watershed Assessment-Tools and Data

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

MAPPING VARIABLE WIDTH RIPARIAN BUFFERS

Sinan Abood1

Riparian buffers are dynamic, transitional ecosystems between aquatic and terrestrial 

ecosystems with well-defined vegetation and soil characteristics. Previous approaches 

to riparian buffer delineation have primarily utilized fixed-width buffers. However, 

these methodologies only take the watercourse into consideration and ignore critical 

geomorphology, associated vegetation and soil characteristics. Utilizing spatial data readily 

available from government agencies and geospatial clearinghouses, such as digital elevation 

models (DEM) and the National Hydrography Dataset, the Riparian Buffer Delineation Model 

(RBDM) offers advantages by harnessing the geospatial modeling capabilities of ArcMap 

GIS, incorporating a statistically valid sampling technique along the watercourse to accurately 

map the critical 50-year plain, and delineating a variable width riparian buffer. Options 

within the model allow incorporation of National Wetlands Inventory (NWI), Soil Survey 

Data (SSURGO), National Land Cover Data (NLCD) and/or Cropland Data Layer (CDL) to 

improve the accuracy and utility of the riparian buffers. This approach recognizes the dynamic 

and transitional natures of riparian buffers by accounting for hydrologic, geomorphic and 

vegetation data as inputs into the delineation process. By allowing the incorporation of land 

cover data, decision makers acquire a useful tool to assist in managing riparian buffers. The 

model is formatted as an ArcMap toolbox for easy installation and does require a Spatial 

Analyst license.

1

Spatial Analyst/Research Fellow, USDA Forest Service, Washington, DC 20250
Watershed Assessments at Multiple Scales
114 Headwaters to Estuaries: Advances in Watershed Science and Management

Watershed Assessments at Multiple Scales

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

PAIRED FORESTED WATERSHED EXPERIMENTS IN THE PIEDMONT 

OF NORTH CAROLINA

Johnny Boggs, Ge Sun, Steven McNulty1

Understanding how regional-specific water resources respond to disturbances can serve 

as useful information to land managers as they aim to set flow targets needed to maintain 

ecological integrity in surface waters or to design riparian buffers for water quality protection. 

There are three distinct land provinces across North Carolina: the Mountains, Piedmont, and 

Coastal Plain. Population density, topography, and distribution of major forest landscapes are 

unique to each region, resulting in a range of different water resource needs and responses 

to land management practices. Experimental forests in the Mountain and Coastal regions of 

North Carolina offer a long history of watershed hydrology and water quality data related 

to sustainability of forest and water resources following silvicultural activities. Little data is 

available for the Piedmont portion of the state. This study addressed this spatial knowledge 

gap through a series of paired watershed studies in the Piedmont at Hill Demonstration 

Forest: control watersheds (HF2 and HFW2) and treatment watersheds (HF1 and HFW1) 

and Umstead Research Farm control watershed (UF2) and treatment watershed (UF1). We 

quantified changes in discharge, water quality, riparian buffer stand dynamics, and buffer 

tree water use after a clear-cut harvest where best management practices (BMPs) were 

installed to protect water quality. We found that discharge in treatment watersheds increased 

dramatically, averaging 240 percent in HF1 and 200 percent in UF1, and 40 percent in HFW1 

during the postharvest period, 2011-2013. Total suspended sediment export in the treatment 

watersheds also increased significantly after harvest due to the increase of discharge quantity 

and movement of in-channel legacy sediment. Stormflow peak nitrate reached its maximum 

concentration during the first two years after harvest in treatment watersheds then declined 

due to nitrate uptake by the rapid regrowth of woody and herbaceous plants. We found that 36 

percent of the UF1 streambank trees were blown down due to opening of the canopy during 

harvest, but caused no measurable increase in mean daily stormflow sediment concentration. 

HF1 residual trees in the buffer used 43 percent more water in growing season postharvest 

(314 mm) than growing preharvest (220 mm) period. This resulted in an 8 percent change 

in stream discharge due to an increase in buffer stand transpiration. Our results align with 

forest management studies in the Mountains and Coastal Plain where temporary increases in 

discharge were accompanied by increased in-channel sediment transport and nutrient exports 

but were not sufficiently disruptive to impact aquatic life and ecological integrity. However, 

percent change in discharge and peak nitrate concentrations tended to be higher in the 

Piedmont when compared to the Mountain and Coastal Plain regions.

1

Johnny Boggs, Biological Scientist, USDA Forest Service, Eastern Forest Environmental Threat Assessment Center, Raleigh, NC 27606

Ge Sun, Research Hydrologist, USDA Forest Service, Eastern Forest Environmental Threat Assessment Center, Raleigh, NC 27606

Steven McNulty, Ecologist, USDA Forest Service, Eastern Forest Environmental Threat Assessment Center, Raleigh, NC 27606
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 115

Watershed Assessments at Multiple Scales

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

VERIFICATION OF HYDROLOGIC LANDSCAPE DERIVED BASIN-SCALE 

CLASSIFICATIONS IN THE PACIFIC NORTHWEST

Keith Sawicz1

The interaction between the physical and climatic attributes of a basin (form) control how 

water is partitioned, stored, and conveyed through a catchment (function). Hydrologic 

Landscapes (HLs) were previously developed across Oregon and are comprised of 

components describing climate, seasonality, aquifer permeability, terrain, and soil 

permeability for over 5,000 assessment units; they therefore represent hydrologic form 

throughout Oregon. This approach was then extended to the three Pacific Northwest 

(PNW) states of Washington, Oregon and Idaho to over 10,000 assessment units. The PNW 

assessment units were developed using the National Hydrography Dataset Plus V2 catchment 

boundaries. Hydrologic landscapes have the advantage of describing how water should flow 

through and out of each HL in continuous space. However, HLs are unable to be verified 

without stream flow information. Hydrologic function was investigated through the extraction 

of characteristics of the long-term climatic and streamflow signals (hydrologic signatures) for 

199 basins in the PNW. Hydrologic signatures include Runoff Ratio, Baseflow Index, Snow 

Ratio, and Recession Coefficients. To compare the PNW HL classification to hydrologic 

signatures, we developed 5 methodologies to aggregate and interpret information provided by 

HLs to the basin scale. These methodologies use the areal fraction of HL composition within 

each basin to cluster basins together into similar classes with respect to both the underlying 

HL composition and hydrologic signature values. For HL aggregation to be considered 

successful, it must show similarity in hydrologic signatures within basin clusters and 

distinctness between basin clusters. We hypothesize that we will find: 1) a way to aggregate 

HLs that form homogeneous and distinct classes 2) strong relationships between HL derived 

basin clusters and hydrologic signatures; 3) signatures related to water balance are explained 

by climatic conditions; and 4) signatures describing flow paths are predicted by terrain, 

soil, and aquifer permeability. Preliminary findings suggest that basins clustered using HLs 

that contribute most to moisture excess and deficit provide basin classes that best separate 

combined hydrologic signature properties.

1

ORISE Post-Doc, US Environmental Protection Agency, Corvallis, OR 97333
116 Headwaters to Estuaries: Advances in Watershed Science and Management

Watershed Assessments at Multiple Scales

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATERSHED AND LONGITUDINAL MONITORING EVENTS

Harold Harbert, Steven Blackburn1

Georgia Adopt-A-Stream partners annually with many organizations, universities and 

watershed groups to conduct sampling events with volunteers at a watershed level. These 

monitoring events range from one-day snapshots to week-long paddle trips. One-day 

sampling events, also called “Blitzs,” River Adventures and River Rendezvous, generally 

target 20-50 sites within a watershed. The multi-day events involve sampling anywhere from 

10 to 20 sites per day, 70-120 sites per event, and are usually part of a larger activity called 

“Paddle Georgia.” The multi-day events are located on a different Georgia river each year 

and bring along hundreds of citizens on the adventure. Partners for these events include 

local governments, watershed organizations, Adopt-A-Stream groups and many other entities 

which provide sampling equipment, technical support and sponsorship. Depending on the 

objectives of the event, data can be collected on many parameters including water quality 

chemistry, bacteria, macroinvertebrates and physical characteristics. Data is posted on our 

website/database and is available for citizens and partners to view in graphs and basic GIS 

or download for analysis. In addition to collecting and sharing the data, small reports are 

written and shared with the community, and the information has been used at the local, state 

and federal level. During this presentation we will discuss Georgia’s volunteer water quality 

monitoring program and how we’ve used watershed-wide sampling events to connect with a 

larger audience, collect and share quality assurance water data, and lessons learned.

1

Harold Harbert, Outreach Manager, Georgia Environmental Protection Division, Atlanta, GA 30354

Steven Blackburn, Program Officer, US Enviornmental Protection Agency, Region 4 Wetlands, Coastal and Ocean Branch, Atlanta, GA 30303
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 117

Watershed Assessments at Multiple Scales

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

A VALIDATION STUDY OF A RAPID FIELD-BASED RATING SYSTEM 

FOR DISCRIMINATING AMONG FLOW PERMANENCE CLASSES OF 

HEADWATER STREAMS IN SOUTH CAROLINA

William Wenerick, Ken M. Fritz, Mitchell S. Kostich1

Classifying streams according to permanence is important in determining regulatory 

jurisdiction and in implementing pollution control programs. Administrators of these 

programs need rapid methods for making timely and defensible decisions. A rapid, field-based 

stream classification method developed in North Carolina compares the overall sum of ordinal 

scores based on observation of 26 geomorphology, hydrology, and biology attributes to 

numeric thresholds in order to preliminarily classify a stream reach as ephemeral, intermittent 

or perennial. Our study was among the first to evaluate the method and directly compare 

classifications based on scores to continuous hydrologic data from electrical resistance sensors 

and from direct observations of instream conditions during discrete wet and dry season 

visits. Ephemeral reaches scored lower than intermittent and perennial, but scores were not 

significantly different between intermittent and perennial reaches. Scores were seasonally 

stable and related to measures of duration, but not frequency. Geomorphology attributes 

were not important in a random forest model. Scores of the presence of baseflow in the dry 

season were more important than those from the wet season. Other important attributes and 

parameters were macrobenthos, rooted upland plants, bankfull width, drainage area, and 

ecoregion. Continuous hydrologic data and statistical analysis can be used to calibrate and 

fine-tune similar tools in other regions.

1

William Wenerick, Project Manager, South Carolina Department of Health and Environmental Control, Columbia, SC 29201

Ken M. Fritz, Research Ecologist, Ecological Exposure Research Division, National Exposure Research Laboratory, US Environmental Protection 

Agency, Cincinnati, OH 45268

Mitchell S. Kostich, Research Biologist, Ecological Exposure Research Division, National Exposure Research Laboratory, US Environmental 

Protection Agency, Cincinnati, OH 45268
118 Headwaters to Estuaries: Advances in Watershed Science and Management

Watershed Assessments at Multiple Scales

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

QUANTIFYING VARIABILITY: PATTERNS IN WATER QUALITY AND 

BIOTA FROM A LONG-TERM, MULTI-STREAM DATASET

Camille Flinders, Douglas McLaughlin1

Effective water resources assessment and management requires quantitative information on 

the variability of ambient and biological conditions in aquatic communities. Although it is 

understood that natural systems are variable, robust estimates of variation in water quality 

and biotic endpoints (e.g. community-based structure and function metrics) are rare in US 

waters; due, in large part, to the need for, but paucity of, consistent, long-term studies. A key 

objective of National Council for Air and Stream Improvement (NCASI) Aquatic Biology 

Program is to guide and inform facilities, researchers, and regulators by conducting research 

that increases the understanding of biota and receiving water responses to effluent exposure. 

Laboratory studies evaluate biological responses to effluent and effluent constituents while 

field studies place potential lower-level effects into the context of higher-level, in-stream 

patterns, and utilizes effluent-biota relationships to develop tools or models that address 

effluent effect concerns applicable to different mills and/or receiving water scenarios. A 

cornerstone of this program is the Long-term Receiving Water Study (LTRWS), which is 

a multi-faceted field and laboratory study designed to evaluate effluent-related responses 

in short- and long-term laboratory bioassays, in-stream water and habitat quality, and the 

structure of fish, macroinvertebrates, and periphyton communities. Initiated in 1998 in 

four pulp and paper mill effluent receiving streams (Codorus Creek, PA; Leaf River, MS; 

McKenzie and Willamette Rivers, OR), water quality and biota are assessed seasonally 

at multiple sites upstream and downstream of the discharge to differentiate point source 

stressor responses from variation that occurs naturally over a stream continuum and to 

evaluate patterns in the context of seasonal and long term annual variability. Assessment of 

water quality in key tributary streams provides additional information in explaining main 

channel water quality patterns. We used this multi-year (n=15), seasonally sampled dataset 

of water quality and biota from multiple sites (n=5-7) to examine spatial and temporal 

variation in select endpoints (basic WQ variables, nutrient concentrations; select fish and 

macroinvertebrate metrics, chlorophyll a). Probability distributions and confidence intervals 

were used to quantify variation across sites and seasons within streams, and as a basis for 

exploring how variability estimates are affected by sample size. A subset of endpoints will be 

presented and differences in patterns across endpoints and streams will be discussed. Study 

results will help guide the design of monitoring studies in terms of number and frequency of 

sampling and study duration.

1

Camille Flinders, Aquatic Biology Program Manager, National Council for Air and Stream Improvement, Anacortes, WA 98221

Douglas McLaughlin, Principal Research Scientist, National Council for Air and Stream Improvement, Anacortes, WA 98221
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 119

Watershed Assessments at Multiple Scales

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATERSHEDS, ECOREGIONS AND HYDROLOGIC UNITS: 

THE APPROPRIATE USE OF EACH FOR RESEARCH AND 

ENVIRONMENTAL MANAGEMENT DECISIONS

James Glover, James Omernik, Robert Hughes, Glenn Griffith, Marc Weber1

It has long been recognized that conditions at a point on a stream are highly dependent on 

conditions upgradient within the topographic watershed. The hydrologic unit (HU) system 

has provided a useful set of nationally consistent, hydrologically based polygons that has 

allowed for the generalization and tabulation of various conditions within the stream and its 

valley. However, environmental managers and researchers sometimes treat all hydrologic 

units as true topographic watersheds, resulting in an exclusion of many data upgradient of 

the sample point, or giving a misleading illustration of watershed conditions. Using ambient 

water quality data collected throughout South Carolina, we tabulated data at the 12 digit HU, 

10 digit HU, 8 digit HU, and true topographic watershed scale for each sample point. For both 

the watershed, which we delineated by clipping, merging and/or dissolving hydrologic units, 

and the unaltered hydrologic units, total and percent area were computed for landcover and 

the level III ecoregion that made up each polygon. For each sample point along the stream, 

descriptive statistics were computed for common water quality parameters. For a given 

ecoregion, water quality parameters in tributary streams were more similar to each other than 

they were to measures taken from the main stem river into which they flowed. While this was 

not unexpected, we show how the common practice of extrapolating to the HU scale, in lieu 

of the topographic watershed, can mask spatial patterns and can potentially result in spurious 

conclusions. These results demonstrate the importance of integrating ecoregion and true 

topographic watersheds for the generalization of surface water data. This integration can lead 

to a better understanding of the natural world, which in turn can result in better management 

decisions.

1

James Glover, Aquatic Biologist, South Carolina Department of Health and Environmental Control, Columbia, SC 29201

James Omernik, Ecologist, US Geological Survey, Corvallis, OR 97333

Robert Hughes, Senior Scientist, Amnis Opes Institute, Bend, OR 97701

Glenn Griffith, Physical Scientist, US Geological Survey, Corvallis, OR 97333

Marc Weber, Geographer, US Environmental Protection Agency, Corvallis, OR 97333

Environmental History of Lowcountry Rice Culture: 

A Current Study of Interdisciplinary Investigations
122 Headwaters to Estuaries: Advances in Watershed Science and Management

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ENVIRONMENTAL RELATIONS BETWEEN INLAND RICE CULTURE AND 

THE COOPER AND WANDO RIVER WATERSHEDS, SOUTH CAROLINA

Hayden R. Smith1

Abstract—This study explains the geographical importance of the Cooper and Wando River watersheds, located east 

of Charleston (SC), in relation to inland rice cultivation during the colonial and antebellum periods. By focusing on the 

geological formation of this watershed, this paper will explain the connection between this plantation enterprise and the 

natural environment. The central South Carolina coastal plain physiography consists of a series of soil deposits during 

the Pleistocene. This topography provided a foundation for which free and enslaved rice cultivators lived and worked. 

By examining the spatial patterns of these actors in relation to the topography, this paper intends to show another 

chapter where the natural environment influences human action. Inland rice cultivation provided a foundation for the 

South Carolina colonial plantation complex and enabled planters’ participation in the Atlantic economy, dependence on 

enslaved labor, and dramatic alteration of the natural landscape. Also, the growing population of enslaved Africans led to 

a diversely acculturated landscape unique to the Southeastern Coastal Plain. Unlike previous historical interpretations, 

which generalize inland rice cultivation in a universal and simplistic manner, this study discusses how agricultural systems 

varied from plantation to plantation. By explaining the importance of planters’ and slaves’ creative alterations of the inland 

topography, this interpretation will emphasize agricultural modes of production as ecological phenomena. 

INTRODUCTION

Reservoir irrigated rice cultivation provided the first 

successful plantation enterprise in South Carolina. 

Despite this agriculture mode of production serving as 

the foundation for the South Carolina colonial economy, 

Lowcountry inland rice cultivation has had an elusive 

history. Unlike the visible tidal rice embankments still 

existing along South Carolina tidal rivers, remnant 

inland fields are harder to find and many presently lie 

in overgrown wooded watersheds. Lack of cultivation 

has transformed the once carefully managed fields 

into second or third growth forests and wetlands. Few 

colonial documents remain that describe the cultivation 

technology. Nineteenth century narratives often confuse 

the more visible tidal method of producing rice with the 

earlier inland method. Relating to these incongruities is 

the understanding that inland, not tidal, rice cultivation 

initially drove rigorous importation of enslaved Africans 

to such an extent that South Carolina became a “black 

majority” by 1739 (Smith 2012). 

This paper explains how planters both adapted to and 

altered the environment by planting rice in inland swamps 

during the colonial and early antebellum periods. By 

explaining the importance of planters’ and slaves’ creative 

alteration of the inland topography, this interpretation 

explains how attention to the environment can present 

a more accurate understanding of the close relationship 

between Lowcountry cultivators and the land. By 

examining environmental relationships, this study can 

contribute to the broader understanding of African and 

European technology transfer in the New World and the 

use of multidisciplinary sources to help answer questions 

previously unattainable through traditional methods.

INLAND RICE CULTIVATION

Inland cultivation began as a simple process for growing 

rice by controlling irrigation schedules on accessible sites. 

But as demand for the crop and land value increased, 

planters spent more energy expanding old inland fields 

and creating new inland rice environments. Planters had 

to creatively adapt a general cultivation model to the 

diverse landscape of the South Carolina Coastal Plain. 

This adaptation to the terrain forced planters to make 

each plantation unique to the environment in an effort 

to maximize available land for efficient rice cultivation. 

Also, cultivators had to work within the limitations of 

this environment by effectively managing water flow and 

lessening the impact of natural disasters. Reacting to the 

opportunities of the global economy, inland planters used 

enslaved labor to clear more land and maximize the crop’s 

output. This practice encouraged the ever-expanding slave 

trade in South Carolina and diaspora of Africans through 

the New World. 

1

Adjunct Professor, Department of History, College of Charleston, Charleston, SC 29424
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 123

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

The basic inland rice field consisted of two earthen 

dams enclosing a low-lying area bordered by subtle 

ridges. Enslaved people built up the embankments with 

available fill from adjoining drainage trenches. The dam 

on higher elevation contained stream or spring fed water 

to form a reservoir, or a “reserve,” that would provide 

a water supply to the lower rice fields (Fig. 1). Once 

cultivators released water from the reservoir, a second 

dam retained this resource to nourish rice fields. Located 

between these two earthen structures was a series of 

smaller embankments and ditches to hold and drain water 

effectively during the cultivation process (Hilliard 1975).

Inland rice cultivation depended upon the simple flow of 

water from high to low ground, as water distributed from 

rainstorms and springs flowed down hill while watersheds 

pulled this resource into creeks and streams. Land level 

enough for rice cultivation, yet with sufficient angle to 

allow proper drainage, took shape throughout the South 

Carolina Coastal Plain. Terrain in this region provided 

ideal situations for inland rice cultivation, for the Atlantic 

Ocean’s rise and fall during the Pleistocene (~2 million to 

~ten thousand years ago) created fingers of small streams 

and creeks that spanned out from higher elevations, and 

merged into larger rivers flowing into the nearby ocean 

(Colquhoun 1969).

As the Atlantic Ocean’s shoreline slowly encroached 

and retreated, barrier island chains and corresponding 

tidal flats formed over the millennia to create scarps and 

terraces. Prehistoric terraces consisted of sand and shells, 

while the backside of these ridgelines consisted of clay 

loam from former tidal marshes and lagoons. Scarps serve 

as physical lines of demarcation between the terraces, 

forming from either erosion of the receding coastline or 

during the depositional stage of former barrier islands.

Water’s movement through these facies coincidentally 

shaped the land, forming knolls, ridges, and troughs, 

Figure 1—Basic inland rice field
124 Headwaters to Estuaries: Advances in Watershed Science and Management

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

which became critical features to rice plantations and 

the people who lived on them. Islands of high pine-lands 

lying within and around the plantations’ swamps enabled 

planters to establish buildings and grazing fields on 

terra firma while creeks flowing around these landforms 

provided the water source and floodplain needed for 

inland rice cultivation. The early agricultural practices 

were necessarily ecologically diverse, as planters had 

to adapt their economic activities with the various 

microenvironments located on their property (Kovacik 

and Winberry 1989).

By focusing on specific examples located in the Cooper 

and Wando River watersheds, this paper will discuss 

how topography helped define irrigation patterns, field 

design, and settlement patterns. This spatial setting 

consists of the Eastern and Western branches of the 

Cooper River, converging with the Wando River to form 

the eastern half of the Charleston Harbor. Both rivers 

originate in the Lower Coastal Plain and flow relatively 

short distance compared to the neighboring Santee River, 

where headwaters begin approximately four hundred 

forty miles away from the coast. Including land covered 

by a 20th century hydro-electric dam project, the Cooper 

River flows approximately sixty miles and traverses four 

of the five Lower Coastal Plain terraces. The Wando 

River flows approximately twenty miles through just one 

terrace. Establishing inland rice cultivation systems in 

these terraces, planters and their enslaved laborers worked 

within the boundaries of these landscapes to create 

agricultural modes of production. At the same time, these 

topographical boundaries influenced settlement patterns 

and provided a pallet for inhabitants to construct a unique 

cultural identity.

Enslaved Africans’ close connection to Lowcountry 

wetlands and small-stream floodplains provided access 

for individuals to express their cultural identity through 

subsistence agriculture. The close proximity of plantation 

settlement highlands and low-lying wetlands enabled 

seventeenth century slaves to construct nearby rice fields 

“on the plantation periphery” (Carney and Rosomoff 

2009, Price 1991). Early plantation settlement patterns 

consisted of the plantation owner and enslaved houses 

within close proximity on highland knolls or ridgelines. 

The Lowcountry topography’s highland swells caused 

by Pleistocene deposits and resulting erosion, created a 

landscape surrounded by bays, streams, creeks, and rivers. 

Slaves’ necessity to grow crops for survival challenged 

them to use available land. For select West Africans 

transplanted in this New World environment, nearby 

wetlands provided similar spatial zones for growing rice. 

Relying on cultural memory, these enslaved cultivators 

constructed embankments for where they could grow 

patches of rice in similar fashion to their homeland. Also 

enslaved laborers’ presence cutting cypress or herding 

cattle in swamps enabled them to become more familiar 

with wetland hydrology. As Peter Wood (1974) notes, 

these “black pioneers” were a mobile population that 

negotiated through Euro-American void swamps by 

tending to their enslaved duties. As part of the “numerous 

aspects of their varied African experience” that took place 

in the Lowcountry, rice became one of many subsistence 

crops grown upon the unwanted land.

Early eighteenth century planters relied on small 

tributaries’ definable floodplains to experiment with 

modes of irrigation control found in dams, embankments, 

ditches, and drains. By 1716, René Ravenel used a 

limestone spring, formed from a downdip in the Floridian 

aquifer system, to irrigate his Pooshee Plantation rice 

fields. Occurring more frequently in the Penholoway 

Terrace, these artesian springs, or fountains by the 

local residents, provided consistent water flow for rice 

plantations throughout the Biggin Swamp community. 

Pooshee Springs was one of six notable fountains 

bordering the basin that established this area as one of 

the central rice zones in colonial South Carolina (Smith 

2012). In turn, as Max Edelson described, enslaved labor 

”made comparatively simple alterations to the land that 

took advantage of the existing contours of its topography” 

(Edelson 2006). Slaves dug into Pooshee’s gray, sticky 

sandy clay loam and threw a dam between the higher fine 

sandy loam to form a reservoir. Up to seventeen slaves 

then constructed a second dam to impound spring fed 

water and maintained the modest twelve-acre enclave.

Towards the coast, the Princess Anne Terrace’s brackish 

tidal rivers presented new challenges for early rice 

cultivators. Because the terrace complex’s close proximity 

to the ocean, Princess Anne began at sea level with a 

gently inclined slope up to twenty feet (Willoughby and 

Doar 2006). The ocean’s incoming tide pushed a salt 

wedge of brackish water against the downward flowing 

rivers. While freshwater hydrology became a critical 

component for tidal irrigation on the Cooper River, the 

Wando River’s limited watershed did not generate enough 

flow to initiate this hydraulic machine. Millennia of the 

Wando’s ebb and flow through the maritime floodplains 

created an interwoven chain of creeks and tributaries. To 

utilize this environment, planters had to construct earthen 

barriers to prevent the brackish tidewater from flowing 

into these low-lying watercourses. 

Richard Beresford’s use of a circumventer shaped network 

of tidal creeks on Charleywood Plantation represents how 

planters initially attempted to cultivate this environment. 

Charleywood rice fields contained the basic structure as 

discussed at Pooshee, yet the lack of elevation change on 

the Wando River floodplains created different aesthetic. 

Whereas Pooshee Swamp consisted of a relatively 

straight watercourse from the spring, Charleywood’s 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 125

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

tidal creeks came from multiple directions, wrapping 

around subtle highland knolls, and converging in Guerin 

Creek. Pooshee’s rice field consisted of a single system 

of two dams bordering the rice. Charleywood, however, 

relied on dams to partition seventy-five acres into seven 

field divisions that allowed improved irrigation control 

compared to flooding a single unit. Five divisions average 

five acres apiece, while the remaining two garaged 

twenty-five acres apiece. Because early inland fields 

were limited to narrow watercourses, their acreage did 

not compare to later tidal systems sprawling across broad 

floodplains. However, early inland cultivators still had to 

pay attention to subtleties of the land, realizing when an 

impounded field was too big to effectively draw water 

on and off the fields. By subdividing the fields, even in 

situations where water directly flowed from one field to 

the next, cultivators could manage the amount of water 

volume on individual plots flooding the entire crop more 

consistently in shorter distances with a low elevation run 

compared to one elongated field with a greater elevation 

change. However, irrigation problems resulted from 

people having to flood each division in order from the 

lowest elevation to the highest elevation. This process 

offered little flexibility in flooding individual sections as 

lower fields had to rely on water impounded upstream 

(Smith 2012). 

By the mid-1700s, planters and their enslaved laborers 

began settling into new inland environments and 

expanding previously unaltered terrain. New agricultural 

methods emphasized that rice cultivators take command 

of water to secure flooding and draining of fields. Planters 

sought solutions to pressure of freshets breaching 

reservoir dams, plus enable systematic flooding and 

draining of fields. Flanking canals, dredged waterways 

that abutted exterior field embankments, optimistically 

provided an answer to this problem. These canals allowed 

cultivators to irrigate fields unilaterally through trunks 

without having to flow each division. Planters’ ability 

to control water was essential when rice fields were on 

different cultivation schedules, either by a few days to 

over a month. Also, trunk minders could add or remove 

water as they saw fit without having to disrupt flood 

stages on adjoining fields. Staggering flood schedules 

avoided possible depletion of impounded water, as springs 

and creeks could recharge the reservoirs before the next 

flood cycle. During freshets, trunk minders could release 

excess water through the flanking canals, bypassing the 

rice fields, and relieving pressure on the back dam.

Planters understanding of water control coinciding 

with their motivation to increase rice acreage let to new 

methods to drawing water onto and off the rice fields. 

Windsor Plantation represented how flanking canals 

took shape. Windsor’s fields fit within the tight boundary 

of the Nicholson Creek floodplain. The elevation 

difference between pineland communities and the 

cypress hardwood forest varied between thirty to forty 

feet within one thousand feet, as the Bethera Scarp’s 

geological “unconformities” allowed Nicholson Creek 

to gorge out steeper “landscape gradients” compared to 

the Penholoway and Queen Anne Terraces. (Colquhoun 

1965) The watershed’s has a dramatic elevation change 

compared to the five to ten foot elevation decline in the 

same one thousand foot increment along the Cooper 

River tidal floodplains. Through the eighteenth century 

the Roches optimistically surveyed four divisions within 

the confines of the scarp to the northwest and the Talbot 

plain’s highlands to the southeast. Yet they has one 

division of forty-five acres developed for rice cultivation 

with twenty-four ”mostly country born” people under 

their control. (Anon. 1784) The Roches relied on the 

predominant knoll forming Nicholson Creek’s southern 

boundary to contain the inland rice fields. Forming a 

crescent shape around a forty-foot bluff, Nicholson Creek 

connected with Turkey Creek to form the Huger Creek 

and serve as the headwaters of the Eastern Branch of the 

Cooper River. This bluff served as an optimal site for the 

Windsor house, slave settlement, and outbuildings.

By 1725, Patrick Roche of Windsor Plantation ordered 

twelve enslaved labors to sculpt fields out of the 

Nicholson Creek cypress bottomlands. Fishbrook Field, 

named after the neighboring plantation on Turkey Creek, 

was the result of cutting trees, removing cypress stumps, 

and shaping forty-five acres of land. Nicholson Creek’s 

meandering channel passed the Fishbrook Field’s western 

border, separated by an earthen embankment. The Roches 

then diverted the creek away from the middle of the 

floodplain by embanking a fifty-five acre division and 

channeling water into a flanking canal (Fig. 2). Unlike 

Fishbrook Field, the second field division impeded 

the natural watercourse with an earthen dam and then 

redirected the creek around the western perimeter 

(Windsor Plantation [Plat]. 1790). A variation of this 

system consisted of two canals flanking the fields on 

each side. Duel canals increased efficiency of moving 

water around fields during freshets and also providing 

additional flexibility flooding and draining individual 

divisions. Slightly higher elevation enabled planters to 

cultivated corn, peas, and indigo at additional provisional 

an economic crops.

As the mid-century Lowcountry plantation enterprise 

became firmly entrenched with Atlantic markets, inland 

planters began to initiate more aggressive irrigation 

practices from a combination from increased enslaved 

labor, acquired agricultural knowledge, improved canal 

networks, and suitable cultivated landscapes. As a result, 

developing inland field systems took on a new aesthetic 

moving away from small acreage with naturally fluid 

boundaries to larger field divisions with geometrically 
126 Headwaters to Estuaries: Advances in Watershed Science and Management

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

rigid embankments. The changing aesthetic correlated 

with emerging tidal irrigation. By the latter half of the 

eighteenth century, Richard Beresford, Jr. depended upon 

upwards of two hundred fifty-three enslaved laborers to 

expand his Charleywood Plantation fields. 

Beresford’s massive enslaved labor force carved 

an intricate grid-like formation of canals, ditches, 

embankments, and dikes over three hundred fifty acres, 

forming twenty-three field divisions that averaged fifteen 

acres apiece (Fig. 3). The new field system was built on 

older Pleistocene deposits, which consisted of more clay 

and shell to retain water compared to the plantation’s 

lower sandy loam field system. To irrigate Charleywood’s 

larger rice fields, enslaved cultivators relied on two 

reservoirs located on the Cainhoy Scarp. With a larger 

watershed of scale compared to earlier examples, the 

reservoirs impounded over forty acres of water flowing 

from meandering creeks and bays common to the Lower 

Coastal Plain’s scarps, where canals channeled the water 

in a linear downward motion.

Charleywood spatial patterns also shifted in relation 

to the plantation’s rice cultivation. Early Charleywood 

inhabitants lived on slightly elevated land located 

approximately one-tenth mile west and only four to five 

feet above the original rice fields, however the settlement 

was abandoned by 1772. According to one eighteenth 

century resident, planters built their homes on the “Edge 

of Swamps, in a damp moist Situation” because they 

wanted “to view from their Rooms, their Negroes at 

Work in the Rice Fields.” By overlooking developed 

agricultural spaces, planters’ views of progress, order, 

and labor management reflected the romantic perception 

of the inland landscape. However, early eighteenth 

century colonists did not understand the connections 

between malaria-carrying anopheles mosquitoes and 

low-lying habitats. What resulted from this ill perceived 

settlement pattern resulted in significant mortality rates. 

Approximately thirty-seven percent of white males and 

forty-five percent of white females born between 1721 

and 1760 and surviving into adulthood in St. John’s 

Parish died before their fiftieth birthday. Charleywood’s 

Figure 2—Windsor Plantation, with rice fields in division “A” and flanking canal wrapping around division “B”
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 127

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

Christ Church Parish offered more dire statistics, where 

eighty-five percent of all white males born between 1721 

and 1760 and surviving into adulthood died before their 

fiftieth birthday (Merrens and Terry 1984). 

By the 1770s, two new settlements appeared on the 

Charleywood landscape. The upper settlement, built in 

the Cainhoy Scarp’s sandy pine flatwoods community, 

was more than likely relocated for healthier living 

conditions. Because Beresford was an absentee planter, 

the upper Charleywood settlement housed the plantation 

overseer and slaves. The other half of Charleywood’s 

enslaved population also had to endure exposed and 

sickly conditions at the second settlement located in the 

middle of the new rice fields. The centrally located Bay 

Hill settlement consisted of four houses, a corn house, a 

mite pen, and a sick house. Bay Hill residents lived on an 

isolated stretch of high land approximately one hundred 

feet wide and four hundred sixty feet wide nestled 

between the Fairlawn Canal and surrounding rice fields.

CONCLUSION

Combining increasing water control projects and everexpanding enslaved labor population with an established 

Lowcountry rice market economy and emerging tidal 

irrigation technology, inland rice field practices changed 

dramatically by the antebellum period. Where planters 

in these environments were limited by water control on 

and off their fields, the increasing network of canals and 

Figure 3—Charleywood Plantation, with new rice fields on top and old rice fields on bottom
128 Headwaters to Estuaries: Advances in Watershed Science and Management

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

drains made expanding field divisions more economically 

accessible. Yet enslaved African-Americans were forced 

to dam more streams for reserve water, dig up soil for 

earthen embankments, and cultivate more acres of rice. 

Studying places like Pooshee, Windsor, and Charleywood 

reveal the ecological complexity of these plantation 

systems. This form of rice cultivation not only required 

that cultivators maintain a critical understanding of how 

to grow rice, but also how to utilize the surrounding 

landscape to the best of their ability. Planters and slaves 

had to control water through floodplains, yet not fall 

victim to natural disasters, such as freshets or droughts. 

To see how these people dealt with water control provides 

a broader picture in understanding specific cultivation 

methods. This story moves beyond how people planted 

the crop, but also how they shaped the land within 

geographical limitations to effectively irrigate rice and 

develop settlement patterns. By connecting the larger 

environment with these specific micro-topographies, one 

may further understand how the Lowcountry topography 

played a role in shaping culture and society as a whole.

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Smith, H.R. 2012. Rich Swamps and Rice Grounds: The 

Specialization of Inland Rice Culture in the South Carolina 

Lowcountry, 1670- 1861. Ph.D. dissertation, University of 

Georgia, 2012. 319 p.

Willoughby, R. H. and Doar, W.R. III. 2006. Solution to the 

Two-Talbot Problem of Maritime Pleistocene Terraces in 

South Carolina. Columbia: South Carolina Department of 

Natural Resources, Geological Survey.

Windsor Plantation [Plat]. 1790. Book D7: 199. Charleston: 

Charleston County Register Mesne Conveyance.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 129

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

CLAY IS EVERYTHING: ARCHAEOLOGICAL ANALYSES OF 

COLONIAL PERIOD INLAND SWAMP RICE EMBANKMENTS

Andrew Agha1

Rice became the market export crop in the early eighteenth century that made South Carolina 

become an economic and agricultural powerhouse after many exotic tropical cultivars failed 

(Carney and Porcher 1993, Carney 1996, 2001, Littlefield 1981, Fields-Black 2008). In 

the late 1990s, scholars had laid out a line of evidence that reveals the roles enslaved West 

Africans played in the Carolina Lowcountry in regards to rice: the methods of planting, the 

technology needed to make it grow in flooded conditions and the methods required to prepare 

it for market (Carney 2001). Once the African element was realized, studies of Carolina’s rice 

culture leaned more towards unlocking the ethnic components of rice cultivation; or, put more 

bluntly, who was responsible for what components of rice technology and agriculture (Alpern 

2013). 

Fueled by cues from major scholars (Carney 1996, Ferguson 1992, Joyner 1984, Littlefield 

1981, Wood 1974), I set out to employ historical archaeology on a, at the time, presumed 

inland swamp rice field embankment that I believed was used for water control (Agha 1999, 

2001). This embankment sits along the line separating higher dry ground from lowland 

hardwood swamp near Willtown Bluff, South Carolina, located on the South Edisto River. My 

excavations in this embankment yielded intact soils that revealed the processes involved in 

its construction. My 7x3 foot cross sections also recovered datable ceramics and artifacts that 

allowed me to interpret who the original embankment and rice field builder was (John Smelie, 

years of tenure: 1719-1727), and these artifacts also helped me identify a later repair episode 

to the bank sometime in the 1750s or early 1760s (James Stobo, years of tenure: 1740-1767) 

(Agha 1999, 2001, Agha and Philips 2009). 

The sequence for the construction steps for this embankment are not simple ditch digging 

and piling of earth in a line haphazardly, as it would appear from simple outside observation. 

The soil profile instead shows a complex configuration of soil types and textures that allowed 

this earthwork to remain intact and unharmed by nature’s reclamation of the old plantation 

lands since roughly 1800. First, the enslaved West Africans, probably already familiar in some 

ways with rice cultivation, approached this virgin piece of landscape and started digging two 

ditches parallel to each other with a 10 foot space between. The humus was piled on top of 

the original ground surface in between the ditches. When the enslaved started to dig into the 

subsoil, here a silty sand followed by a clayey sand, they piled that up along the man-made 

ridge next. Figure 1 displays the cross section profile and photo, showing these events. The 

artifacts that show the repair episode lie between the subsoil core and the topmost darker fill. 

This particular embankment is roughly 2,000 feet long and is in a perfect line with no angle 

changes or turns.

 This embankment was needed to drain an adjacent work area to the north, and its ditches 

also served as transport for water to drain from the uplands down towards the river swamp 

where I identified a fresh water reservoir for formal inland rice fields. Ten years after 

conducting these first excavations I had the opportunity to dig a cross section in a bank 

within identified inland rice fields. This bank lies at the headwaters of the Bluehouse Swamp 

1

Doctoral Candidate, Department of Anthropology, University of South Carolina, Columbia, SC 29208; President, Archaeological Research Collective, 

Inc., Charleston, SC 29407
130 Headwaters to Estuaries: Advances in Watershed Science and Management

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

near Ladson, South Carolina, and belonged to a plantation that likely started rice agriculture 

before 1740 (Agha and others 2010). This bank has a parallel twin, and together these banks 

support a major ditch or minor canal. Water has flowed between these berms since the late 

eighteenth century. While similar to the Willtown example – water transport – the methods of 

construction are very different. 

The enslaved first excavated a wide swath of humus that included the space for the ditch and 

both embankments. Once they reached subsoil clay, they then excavated the ditch deeper 

(refer to bottom of Fig. 1). The clay quarried out of the ditch was then piled carefully on 

Figure 1—Profile drawing and photo of embankment excavation at Willtown 

(top), profile drawing and photo of embankment at Bluehouse Swamp (bottom).
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 131

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

either side of the cut, so that two linear mounds or “walls” were constructed on either side 

of the ditch. Then, coarse sand from a foreign location was piled up next to the clay ridge 

opposite the ditch. The enslaved Africans then mixed large lumps of clay the size of softballs 

into the piled sand. Overlying this clay ridge and coarse sand is a homogenous silty loam and 

clay mixture, followed by a homogenous clayey loam to cap the bank and create the surface. 

The coarse sand does not occur naturally in either the swamp or terrestrial landscape; its 

origination, function and purpose are unknown. It may have facilitated stability or drainage 

within the bank. Besides the presence of this sand, the use of clay here is a revelation. 

West Africans have constructed buildings out of clay and earth for centuries. They have made 

pottery for almost 8,000 years (Clark 1970). As slaves, they had an ancestral knowledge of 

clay that far surpassed the personal experience of their British owners. The enslaved married 

the clay fill to the intact surface of the clay subsoil so perfectly I was unable to discern a line 

separating the two. In essence, these banks create a “clay pipe” for major water transport, 

and exhibit a foresight not seen in any of the seven embankments I have excavated in both 

swamp and upland settings. Clay cores have been identified in several upland examples, 

but the use of clay in this fashion shows a technology that has not been identified in the 

Carolina Lowcountry before. The two embankments I present here are similar in function 

but different in scope. Rice field construction was not simple “ditch-digging” by mindless 

workers beaten by the Middle Passage and their planter-owners. It was instead a hydrological 

engineering marvel concocted through cultural interaction and expertise. Future studies of 

banks throughout the Lowcountry could reveal correlates between England’s drained fens and 

West Africa’s mangrove rice fields. Regardless of their roots, inland rice embankments are the 

largest surviving architecture made by not only African hands, but possibly of African minds.

LITERATURE CITED

Agha, A. 1999. African-American Rice Dike Construction. In: 

Willtown: An Archaeological and Historical Perspective. 

Archaeological Contributions 27. South Carolina Department 

of Archives and History, Columbia. 275-282. 

Agha, A. 2001. 38CH1659: An Analysis of the Cultural Material 

and Deposits in an Eighteenth Century Inland Swamp Rice 

Embankment. On file at the Charleston Museum, Charleston, 

South Carolina. 21 p.

Agha, A.; Philips Jr., C.F. 2009. Landscapes of Cultivation: 

Inland Rice Fields as Landscapes and Archaeological Sites. 

African Diaspora Archaeology Newsletter. http://www.

diaspora.illinois.edu/news0909/news0909.html#1. 28 p. 

[Date accessed: February 15, 2015].

Agha, A., Philips, Jr. C.F., Fletcher, J. 2010. Inland Swamp 

Rice Context, c. 1690-1783. National Register of Historic 

Places Multiple Property Documentation Form. Prepared 

by Brockington and Associates, Inc., Charleston, South 

Carolina. 134p.

Alpern, S.B. 2013. Did Enslaved Africans Spark South 

Carolina’s Eighteenth-Century Rice Boom? In: African 

Ethnobotany in the Americas. New York: Springer. 35-66.

Carney, J.A. 1996. Landscapes of Technology Transfer: Rice 

Cultivation and African Continuities. Technology and 

Culture 37. 5-35.

Carney, J.A. 2001.Black Rice: The African Origins of Rice 

Cultivation in the Americas. Cambridge: Harvard University 

Press. 256 p.

Carney, J.A and Porcher, R. 1993. Geographies of the Past: 

Rice, Slaves, and Technological Transfer in South Carolina. 

Southeastern Geographer 33. 127-147.

Clark, J.D. 1970. The Prehistory of Africa. New York: 

Praeger. 302 p.

Ferguson, L.G. 1992. Uncommon Ground: Archaeology and 

Early African Americans 1650-1800. Washington, DC: 

Smithsonian Institution Press. 186 p.

Fields-Black, E. 2008. Deep Roots: Rice Farmers in West Africa 

and the African Diaspora. Indianapolis: Indiana University 

Press. 296 p.

Joyner, C.1984. Down by the Riverside. Urbana: University of 

Chicago Press. 384 p.

Littlefield, D.C. 1981. Rice and Slaves, Ethnicity and the Slave 

Trade in Colonial South Carolina. Urbana: University of 

Illinois Press. 216 p.

Wood, P.H. 1974. Black Majority: Negroes in Colonial South 

Carolina from 1670 through the Stono Rebellion. New York: 

Norton and Company. 384 p.
132 Headwaters to Estuaries: Advances in Watershed Science and Management

Environmental History of Lowcountry Rice Culture: A Current Study of Interdisciplinary Investigations

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ADVANCED GEOSPATIAL TECHNIQUES AND ARCHAEOLOGICAL 

METHODS TO INVESTIGATE HISTORICAL RICE CULTIVATION AT 

WORMSLOE HISTORIC SITE

Alessandro Pasqua1

Despite much of the environmental history of Wormsloe State Historic Site on the Isle of 

Hope, Georgia having previously been documented and described, there are still some aspects 

that require deeper investigation. For example, whether rice cultivation was ever performed 

at Wormsloe is a question which does not have a definitive answer. The primary goal of this 

study, therefore, is the investigation of the Isle of Hope landscape through remote sensing 

techniques such as terrestrial laser scanning (TLS) and unmanned aerial systems (UAS) 

to identify archaeological evidence related to historical rice cultivation. Terrestrial laser 

scanning will be employed to create an accurate and high resolution 3D bare earth digital 

elevation model (DEM) of the areas under investigation in order to analyze present-day 

microtopographic features that may be indicative of old rice fields such as ditches, dikes, 

and embankments. Furthermore, the use of UASs will provide a detailed aerial view of 

the study areas that can be used to generate a geovisualization of the historical topography 

and landscape potentially present during the late 18th century and throughout the 19th 

century. The collection of multiple images of the terrain from different angles will allow 

the employment of an emerging technique in photogrammetry known as Structure from 

Motion (SfM) to create 3D models of the areas under investigation. This study also employs 

archaeological methods such as phytolith analysis to determine the presence of rice plant 

deposits in the areas where historical rice cultivation is suggested. The results of this study 

will improve the current understanding of Wormsloe’s historical land use and development, as 

well as its archaeological and historical significance.

1

PhD Candidate -Wormsloe Fellow, Department of Geography, University of Georgia, Athens, GA 30602
Coastal Drought
134 Headwaters to Estuaries: Advances in Watershed Science and Management

Coastal Drought

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

DROUGHT AND COASTAL ECOSYSTEMS: AN ASSESSMENT OF 

DECISION MAKER NEEDS FOR INFORMATION

Kirsten Lackstrom, Amanda Brennan, Kirstin Dow1

The National Integrated Drought Information System (NIDIS) is in the process of developing 

drought early warning systems in areas of the U.S. where the development and coordination 

of drought information is needed. In summer 2012, NIDIS launched a pilot program in North 

and South Carolina, addressing the uniqueness of drought impacts on coastal ecosystems. The 

monitoring and management of drought in coastal regions presents several challenges. While 

commonly used drought indices incorporate data such as rainfall, streamflow, soil moisture, 

groundwater levels, and snow pack, such indices were developed for upland areas and may 

not be appropriate indices for characterizing coastal drought. Furthermore, current systems of 

drought management focus primarily on agricultural impacts, fire risks, and maintaining water 

supplies for municipal and industrial use, energy production, and navigation. Understanding 

of drought impacts on other interests and sectors (e.g. environmental resources, public health, 

and water quality) remains limited. In addition, these impacts are currently not well integrated 

into existing planning and response processes at national, regional, state, and local levels. 

This paper introduces the NIDIS-Carolinas program and provides information about one 

of the pilot projects. Interviews with fishermen, outdoor recreation business owners, and 

land managers in the Beaufort County (SC) and Carteret County (NC) areas were conducted 

to document and assess local-level experiences with drought and decision makers’ needs 

for drought information and resources in the coastal Carolinas. Their concerns center on 

water quality conditions, particularly salinity levels and fluctuations, and the availability of 

freshwater to meet the needs of coastal animals, plants, and habitats. Fluctuating salinity 

levels affect the movement, location, and abundance of many aquatic species, thereby 

affecting their accessibility to fishers. On managed lands, drought conditions increase 

fire risks and make impoundments unsuitable for waterfowl and fish, thereby affecting 

conservation objectives and limiting recreational use of those areas. Interviewees do not 

regularly use formal sources of drought information but consider a range of locale-specific 

information related to weather (precipitation, temperature), salinity, wind, tides, and other 

environmental conditions in making decisions. Interviewees indicated interest in baseline 

data regarding “normal” and extreme hydroclimate conditions and integration of drought 

information with other coastal and ecological monitoring efforts. Findings from this project 

will help inform other components of the program, including the development of a drought 

index for coastal regions based on USGS real-time salinity measurements, the identification of 

ecological thresholds, and testing of ecological indicators of drought for coastal ecosystems.

1

Kirsten Lackstrom, Research Associate, Carolinas Integrated Sciences and Assessments, Department of Geography, University of South Carolina, 

Columbia, SC 29208

Amanda Brennan, Climate Outreach Specialist, Carolinas Integrated Sciences and Assessments, Department of Geography, University of South 

Carolina, Columbia, SC 29208

Kirstin Dow, Professor, Carolinas Integrated Sciences and Assessments, Department of Geography, University of South Carolina, Columbia, SC 29208
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 135

Coastal Drought

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

DEVELOPMENT OF A COASTAL DROUGHT INDEX 

USING SALINITY DATA

Paul Conrads, Lisa Darby1

The location of the freshwater-saltwater interface in surface-water bodies is an important 

factor in the ecological and socio-economic dynamics of coastal communities. It influences 

community composition in freshwater and saltwater ecosystems, determines fisheries 

spawning habitat, and controls freshwater availability for municipal and industrial water 

intakes. These dynamics may be affected by coastal drought through changes in Vibrio 

bacteria impacts on shellfish harvesting and occurrence of wound infection, fish kills, harmful 

algal blooms, hypoxia, and beach closures. 

Many definitions of drought have been proposed, with most describing a decline in 

precipitation having negative impacts on water supply and agriculture. Four general types 

of drought are recognized: hydrological, agricultural, meteorological, and socio-economic. 

Indices have been developed for these drought types incorporating data such as rainfall, 

streamflow, soil moisture, groundwater levels, and snow pack. However, these drought indices 

were developed for upland areas and may not be appropriate indices for characterizing 

drought in coastal areas. Because of the uniqueness of drought impacts on coastal ecosystems, 

a need exists to develop a coastal drought index. The availability of many real-time and 

historical salinity datasets provides an opportunity to develop a salinity-based coastal drought 

index.

The challenge of characterizing salinity dynamics in response to drought is excluding 

responses attributable to occasional saltwater intrusion events. We applied various statistical 

and numerical techniques to evaluate the most appropriate approach to develop salinity 

drought indices. An approach similar to the Standardized Precipitation Index was modified 

and applied to salinity data obtained from sites in South Carolina and Georgia, USA. Coastal 

drought indices characterizing 1-, 3-, 6-, 9-, and 12 month drought conditions were developed. 

Evaluation of the coastal drought index indicates that the index can be used for different 

estuary types (for example, brackish, olioghaline, or mesohaline estuaries), for regional 

comparison between estuaries, and as an index for wet conditions (high freshwater inflow) 

in addition to drought conditions. The development of the various drought characteristic 

intervals (1-, 3-, 6-, 9-, and 12 month) allow for the coastal drought index to be correlated 

with environmental response variables that occur on different time intervals.

1

Paul Conrads, Surface Water Specialist, US Geological Survey, Columbia, SC 29210

Lisa Darby, Research Meteorologist, National Oceanographic and Atmospheric Administration, Boulder, CO 80305
136 Headwaters to Estuaries: Advances in Watershed Science and Management

Coastal Drought

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

A WATERSHED-SCALE CHARACTERIZATION OF 

DISSOLVED ORGANIC CARBON AND NUTRIENTS ON THE 

SOUTH CAROLINA COASTAL PLAIN

Daniel L. Tufford, Setsen Altan-Ochir, Warren Hankinson1

Dissolved organic matter (DOM) is recognized as a major component in the global carbon 

cycle and is an important driver of numerous biogeochemical processes in aquatic ecosystems, 

both in-stream and downstream in estuaries. This study sought to characterize chromophoric 

DOM (CDOM), dissolved organic carbon (DOC), and dissolved nutrients in major rivers and 

their tributaries of the South Carolina Coastal Plain as a screening assessment of the impact 

of land cover, soils, stream order, and other factors on DOC characteristics and water quality. 

During eight trips from June 11 to July 9, 2014 throughout the South Carolina Coastal Plain, 

we visited 54 sites and collected water samples for laboratory analysis of DOM ultraviolet 

absorbance and concentrations of DOC, dissolved organic nitrogen (DON), and dissolved 

inorganic nitrogen (DIN). Sample sites included headwater wetlands and springs, streams 

and rivers, and water table monitoring wells. Spectral analysis of the filtered water samples 

was done from 200-800 nm using a Shimadzu UV-1700 spectrophotometer. We calculated 

the spectral ratio (SR, the ratio of slope coefficients at 275-295 nm: 350-400 nm) to facilitate 

broad characterizations of the nature of the CDOM in the water based on stream order, water 

type (black, brown, clear), and physiography (lower Coastal Plain (LCP), upper Coastal 

Plain (UCP)). We performed analysis of variance (ANOVA) to test for significant differences 

(p<.05) in measured values and interaction and multiple regression to determine dominant 

influences of land cover and soils. Dependent variables were DOC, SR, DON, and DIN. 

Independent variables were proportions of land cover types and soil order. ANOVA showed 

the largest concentrations of DOC occurred in black water and in low order streams. The DOC 

concentration was larger in black water on the LCP than the UCP. There were significant 

differences in SR (lowest in LCP and low order streams), DON concentration (largest on 

LCP), and DIN (largest in clear water on the UCP). Regression analysis indicated that most 

of the variability in DOC concentration was explained by amount of forested wetlands and 

soil type (mostly Spodosols) in the watershed. Most of the variability for both DON and DIN 

was explained by the amount of agricultural land cover although for DON some soil orders 

were dominant on the LCP and in low order streams. There were few significant regression 

models for SR and no clear patterns. Our results indicate that low order streams on the Coastal 

Plain are important channels for delivery of high molecular weight organic carbon to coastal 

estuaries.

1

Daniel Tufford, Research Associate Professor, Department of Biology, University of South Carolina, Columbia, SC 29208 

Setsen Altan-Ochir, Rodgers Fellow in Environmental Studies, Department of Geology, Cornell College, Mt. Vernon, IA 52314 

Warren Hankinson, Research Technician, Marine Science Program, University of South Carolina, Columbia, SC 29208
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 137

Coastal Drought

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE EXTENT OF TIDAL INFLUENCE IN THE 

WACCAMAW RIVER, SOUTH CAROLINA

Benjamin Thepaut, John Shelton, Susan Libes, 

Paul Conrads, Robert Sheehan1

The Waccamaw River Basin is located in the coastal plain and meanders from North Carolina 

to South Carolina. This tidal black-water river flows parallel to the coast past the cities of 

Conway and Georgetown, terminating in Winyah Bay. The river is hydrologically connected 

to the Atlantic Intracoastal Waterway (AIW) and experiences semi-diurnal tides with a range 

classified as micro-tidal (< 6.5 feet). The semi-diurnal tidal amplitude in the Waccamaw 

River declines with increasing distance upstream from Winyah Bay and the AIW. Temporal 

variations in the longitudinal tidal gradient of Winyah Bay, AIW, and the Waccamaw River 

reflect varying effects of astronomical tides, weather, and streamflow. 

Streamflow data collected at Reaves Ferry at river mile 63.0 showed that when water levels 

receded in early September 2013, a semi-diurnal tidal amplitude of 0.4 to 1.0 feet was 

recorded in addition to reversing stream velocity. Improved understanding of the hydrology 

at these tidal freshwater reaches would provide valuable information for water-resource and 

land-use planning and management. 

In order to explain the temporal difference in variance a time series model, Auto Regressive 

Integrative Moving Average (ARIMA) was used in the analysis of the tidal reach based 

upon hourly averaged observations from 06/21/2013 to 09/12/2014. The upstream, local, 

and downstream data were hourly averaged and analyzed with a multiple regression and 

ARIMA. A multiple regression model was used to systematically show that all the predictors 

were significant (r2=0.921, <0.03 at p=0.05) in describing variance of water level at Reaves 

Ferry. Results from the ARIMA show that all tidal reach predictors were significant (<0.00 at 

p=0.05) in describing water level at Reaves Ferry.

The low gradient of the coastal plain and low river flow allow for significant tidal influence 

along the Waccamaw River. The ARIMA time-series model was successfully able to delineate 

the hydrograph at Reaves Ferry of tidal and non-tidal scenarios. At the monthly-scale, there 

are clear patterns between downstream and upstream predictors, which are shown or are 

evident in the Reaves Ferry hydrograph. The frequency and duration of flooding in tidal 

freshwater forested wetlands is highly variable based on these predictors in the Waccamaw 

River. Future study plans aim to examine the distribution of TFFW and analyze water-quality 

events in conjunction with tidal processes. This information aims to benefit local scientists 

and highlight the importance of USGS long-term gaging stations.

1

Benjamin Thepaut, Intern Hydrologist, US Geological Survey, Columbia, SC 29210

John Shelton, Associate Director, US Geological Survey, Columbia, SC 29210

Susan Libes, Professor of Marine Science and Chemistry, Coastal Carolina University, Conway, SC 29528

Paul Conrads, Surface Water Specialist, US Geological Survey, Columbia, SC 29210

Robert Sheehan, Professor of Statistics, Coastal Carolina University, Conway, SC 29528

New Insights into Studies on Long-term 

Experimental Watersheds to Address 

Contemporary Emerging Issues

(PART 2)
140 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

HYDROLOGIC CHANGE IN A COAST REDWOOD FOREST, 

CASPAR CREEK EXPERIMENTAL WATERSHEDS: 

IMPLICATIONS FOR SALMONID SURVIVAL

Elizabeth Keppeler1

Abstract—The 52-year record of streamflow from the Caspar Creek Experimental Watersheds shows a trend toward 

decreasing rainfall and streamflow during the fall season when coho salmon (Oncorhynchus kisutch) migrate upstream 

to spawn. Rainfall records show a slight declining trend in fall totals and a slight increasing trend in spring totals since 

1962, but only November shows a significant decrease in rainfall with year. Mean daily flows between late-October and 

mid-December declined by about one third. “Fish-passage” flows became less frequent in November. These flows were 

correlated with adult coho abundance estimates. The first-of-season peak flow, needed to breach the seasonally-formed 

sandbar at the Caspar Creek estuary and open access to upstream spawning habitat, occurred later. Results were similar on 

the South Fork (logged 1967-1973) and North Fork (logged 1985-92).

INTRODUCTION 

During the fall and winter of 2013-14, coho salmon 

(Oncorhynchus kisutch) were thwarted from making their 

annual migration from the ocean to their native streams 

along much of California’s coast because of persistent 

drought and lack of streamflow. These anadromous fish 

are acutely dependent on fall freshets, which ordinarily 

breach seasonally-formed sandbars at river mouths and 

open access to the spawning habitat of north and central 

coast streams. Although numerous factors affect salmonid 

survival and productivity, climatic variation (including 

severe storms, drought, El Niño-Southern Oscillation 

(ENSO), and hydrologic regime shifts) can alter both 

marine and freshwater habitat conditions and impact 

salmonid abundance. The marked decline of California’s 

coho populations triggered federal listing in 1996 and 

1997 under the Endangered Species Act, as well as state 

listing in 2005. Maintaining and increasing the number of 

spawning adults is a key goal for coho recovery (CDFG 

2004, NMFS 2012). Adequate flows for fall spawning, 

spring out-migration, and summer rearing conditions are 

essential to species survival along the California coast 

south of Punta Gorda.

Climatic change is affecting background environmental 

conditions and may result in altered timing, magnitudes, 

and frequencies of hydrologic processes. Shifts in runoff 

have been documented in mountainous, snowmeltdominated watersheds of the western U.S. (Safeeq and 

others 2014, Peterson and others 2008, Stewart and 

others 2004). Null and others (2010) reported changes in 

centroid timing (CT) of runoff in high elevation westslope Sierra Nevada watersheds, but found little change 

in runoff timing in low elevation watersheds that did not 

reach the Sierra Nevada Crest. In north coastal California, 

Madej (2011) examined long-term climate data and runoff 

records from 19 gauged watersheds and found no trends 

in annual rainfall other than a decrease in September. No 

change in the CT was detected in these lower elevation 

coastal streams. Summer low-flow (defined as 7-day 

minimum) decreased at 10 of the sites, including North 

Fork Caspar Creek. Burt and others (2014) examined the 

impacts of extreme climatic variability on post-logging 

streamflow response at the H.J. Andrews Experimental 

Forest, Oregon. Because interannual variability is high 

relative to long-term climate trends (Abatzoglou and 

others 2014), data sets spanning multiple decades are 

essential for analyzing the hydrologic response to climatic 

variation and forest management. 

For this analysis, 52-year rainfall and streamflow records 

from the Caspar Creek Experimental Watersheds were 

used to explore trends in the seasonal distribution of 

precipitation and runoff with particular emphasis on the 

critical fall period when coho migrate to the headwaters 

of Caspar Creek. Understanding these trends is essential 

if strategies are to be developed for effectively managing 

water resources and mitigating potential harm to 

endangered salmonid populations resulting from altered 

hydrologic regimes.

1

Hydrologist, USDA Forest Service, Pacific Southwest Research Station, Fort Bragg, CA 95437
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 141

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

STUDY AREA

Caspar Creek is a perennial fifth order coastal stream 

draining 21.7 km2 of largely forested topography in the 

Coast Range of northern California. At its headwaters, 

10 km from the Mendocino coast, elevations attain 322 

m and hillslopes can be as steep as 60° (Fig. 1). The 

forest, composed primarily of coast redwood (Sequoia 

sempervirens) and Douglas-fir (Pseudotsuga menziesii), 

was first logged from the 1860’s to 1904 and continues 

to be managed for research and timber production in the 

modern era.

Two experimental watersheds, the 473-ha North Fork 

(NF) and the 424-ha South Fork (SF), occupy the Caspar 

Creek headwaters in the Jackson Demonstration State 

Forest. Within the experimental watersheds, rainfall, 

streamflow, and sediment yields have been measured 

continuously since 1962 as part of a long-term partnership 

between the California Department of Forestry and Fire 

Protection and the U.S. Forest Service. Road construction 

and harvests of second-growth timber were carried out 

in 1967, 1971-1973 (SF) and in 1985-1986, 1989-1992 

(NF). Beginning in 1962, NF and SF streamflow has been 

Figure 1—Central California Coast Coho Salmon Evolutionarily Significant Unit 

and Caspar Creek Watersheds.
142 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

measured at sharp-crested compound weirs, and recording 

rain gauges have been in operation at multiple elevations 

(Henry 1998). 

Annual precipitation averaged nearly 1150 mm and 

varied from 305 mm to 2202 mm over the 52 year record 

at the S620 rain gauge (Fig. 1). Snowfall is rare and 

hydrologically insignificant. Roughly 95 percent of annual 

rainfall occurs between October and April, with the 

centroid of annual precipitation occurring in mid-January. 

Night and morning fog occurs frequently during summer 

months. Temperatures are mild, with mean monthly 

temperatures ranging between 7°C and 15°C. Stream 

temperatures measured above the NF weir are considered 

to be within the desirable range for native fish, with 

weekly averages peaking during August-September at 13 

to 15.5°C and dropping to winter minimums of 5 to 7°C.

Caspar Creek lies within the Central California Coast 

Coho Salmon Evolutionarily Significant Unit (CCC-ESU) 

and supports anadromous coho salmon (Oncorhynchus 

kisutch) and steelhead (Oncorhynchus mykiss) along 14 

km of channel. Coho travel upstream in mid-November 

through early January to spawn. Eggs hatch after five to 

seven weeks, and fry emerge from stream gravels during 

March through May or later. As the summer progresses, 

juveniles move to deeper pools to feed and grow. Coho 

typically emigrate to the ocean as yearlings from April 

through June, and then return to their native streams to 

spawn after two years in the ocean (CDFG 2004). Both 

spawning and out-migration are triggered by short-term 

increases in discharge and changes in stream temperature. 

Estimates of “escapement,” the number of adult salmon 

surviving the marine environment to return to spawn, are 

used to monitor current abundances and predict future 

populations. These data demonstrate high interannual 

variability and declining regional abundance (Gallagher 

and others 2014) despite the implementation of fishing 

restrictions, increasingly stringent habitat protection 

measures, and major restoration efforts in recent decades.

METHODS

Daily precipitation totals measured near the confluence of 

the SF with mainstem Caspar were used in this analysis. 

Trends in monthly and seasonal precipitation were 

examined using linear regression with water year (here 

considered to begin on August 1st) as the independent 

variable. In addition, because fall rainfall accumulations 

must increase discharges enough to erode the sandbar 

that forms at the mouth of Caspar Creek before coho can 

return to spawn, exceedance dates for seasonal thresholds 

of 300 mm and 500 mm were calculated for each year. 

Field experience suggests that 300 mm of cumulative 

precipitation is necessary to diminish the soil moisture 

deficit sufficiently to generate a storm flow, and 500 mm 

is needed to wet up the soil profile to groundwater depth.

NF and SF ten-minute discharges, mean daily flow 

(MDF), and instantaneous peak flows were examined. 

Flow data for hydrologic year (HY) 1977 and early 

HY63 were unavailable. Several approaches were used to 

evaluate changes in seasonal flow over the 52-year record. 

Analysis was first performed graphically to visually 

compare streamflow patterns by decade. The mean and 

median MDF by date were calculated for each decade, 

and 30-day averages were computed to smooth the 

resulting flow index. This visual analysis revealed a fairly 

distinct divergence in the later two decades relative to the 

first three, and the data were consolidated accordingly into 

two groups: HY63-92 and HY93-12. The difference in 

average MDF between the two groups was then assessed 

to provide a measure of change in the seasonal runoff 

patterns. Additionally, the data were divided into two 

groups of equal years for T-test comparisons of mean 

MDF in the earlier versus later streamflow record.

Next, flow durations for fall “fish-passage flows” were 

tallied from 10-minute discharge records. Passage flows 

for adult anadromous salmonids encompass a range of 85 

to 1331 L s-1 according to NOAA Fisheries and California 

Department of Fish and Wildlife design guidelines 

for the Caspar Creek fish ladders (Winzler & Kelly 

and others 2006). For each water year, instantaneous 

discharges within this range were tallied by month for the 

November to January spawning season, omitting HY63 

and HY77 where the records were incomplete. These flow 

durations, expressed as cumulative days, were regressed 

against water year to evaluate trends. Caspar escapement 

estimates were regressed against seasonal passage flow 

durations to determine if coho returns were correlated to 

these flows. Escapement estimates were only available for 

2000-2014 (Gallagher and others 2014).

Lastly, the seasonal distribution of storm peaks was 

explored. NF instantaneous peak flows greater than 

680 L s-1 were tallied by date. Although the threshold 

is arbitrary biologically, this magnitude of peak flow 

(0.15-year recurrence interval at the NF weir) is used to 

define storms for many of the flow and sediment yield 

analyses performed on the Caspar Creek data set. Caspar 

Creek flows of this magnitude are sufficiently powerful 

to erode the sandbar at the mouth and typically result 

in elevated discharges of sufficient duration for coho 

migration to occur. The date of the first fall peak, the last 

spring peak, and the length of the storm season (expressed 

as the number of days between the two) were calculated 

for each water year. Regression analysis was used to 

evaluate trends.

RESULTS

Most indices of fall rainfall and streamflow showed 

declining trends with time, but few were statistically 

significant. In contrast, spring trends were weakly 

positive, but none were statistically significant (p=0.10). 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 143

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

Rainfall

Caspar Creek rainfall records suggest a slight declining 

trend in fall totals and a slight increase in spring totals 

since 1962, but only November shows a significant 

decrease (p=0.05) in rainfall with year. Regression results 

indicate that the date on which cumulative precipitation 

exceeded 300 mm has shifted to occur later in the season 

(p=0.093), resulting in a predicted delay of 22 days in 

attaining this seasonal threshold (Dec04 in 1963 versus 

Dec26 in 2014). A similar trend observed in the 500 mm 

exceedance date was also significant (p=0.092) (Fig. 2). 

Streamflow

Streamflow response reflects not only rainfall inputs, 

but is also influenced by soils, topography, vegetation, 

and antecedent moisture conditions. The comparison of 

30-day average MDF for 1963-1992 with that since 1992 

shows reduced fall flows in recent decades relative to the 

earlier data (Fig. 3). On the NF, MDF between October 

24th and December 14th averaged 86 L s-1 for the first three 

decades of record versus 59 L s-1 for the most recent two 

decades – a decline of 31 percent. The largest differences 

were observed in late November. When these data were 

divided into two sets of 24 years (HY64-88 and HY89-

12), the mean of the more recent data was significantly 

lower (p=0.021) than that of the earlier time period. For 

the remainder of the year, average MDF was slightly 

higher in the two most recent decades. SF results were 

similar to NF, showing a decline of one third (89 versus 

59 L s-1) for October 24th and December 14th and slightly 

elevated flows during late-spring. These similarities 

suggest that logging was not an influential factor in this 

result.

Of greater biological significance is the timing and 

duration of fish-passage flows (85 to 1331 L s-1). About 18 

percent of Caspar Creek weir flows fall within this range. 

No significant trends in annual frequencies of these flows 

were detected. Passage flows for November-December 

showed decreasing, but statistically insignificant, trends 

with year. Only November passage flows exhibited a 

significant decreasing trend over the length of record 

(p=0.013 NF, p=0.017 SF). Mean frequency of these 

flows during the November-January spawning season is 

27 days. Although November accounts for only 15 percent 

of these flows, November streamflow exceeded the 

minimum fish-passage flow during 20 (NF) and 18 (SF) 

of the 25 years between 1964 and 1989, while November 

flows allowed fish passage during only 12 (NF) and 10 

(SF) of the last 25 years (Fig. 4).

Further evidence of a possible hydrologic regime shift 

was observed in the seasonal distribution of NF storm 

peaks greater than 680 L s-1. Fall storms (OctoberDecember) have not occurred during 18 of 52 water years, 

with 13 stormless falls occurring since 1989. Although the 

declining trend was not statistically significant, stormless 

falls were twice as frequent during the second half of the 

52-year record. Mean fall storm count for 1989-2014 was 

significantly lower than for 1963-1988 (p=0.081). The 

apparent increasing trend in spring storm counts was not 

significant. Similarly, examination of the date of the first 

and last storm of the season showed a significant delay 

in the arrival of the first storm (p=0.013), while the delay 

Figure 2—Seasonal rainfall threshold exceedance dates. Both 300 mm and 500 mm trends significant (p=0.093, 

0.092). Median date for 300 mm is December 11th (day 133) and for 500 mm is January 5th (day 170). (Less than 500 

mm precipitation recorded during HY77).

90

120

150

180

210

240

19631965196719691971197319751977197919811983198519871989199119931995199719992001200320052007200920112013

Days since August 1st

Water Year

500mm

300mm
144 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

in arrival of the final storm of the extended winter season 

was not significant. This pattern might appear to indicate 

a shortened high flow season; however that trend was also 

not significant (Fig. 5).

DISCUSSION 

While interannual variability is large relative to trends 

observed here, evidence of a possible hydrologic regime 

shift is present for both NF and SF, suggesting that 

timber harvest history was not a strong influence on the 

overall trend. Fall season rainfall, fish-passage flows, 

and first-of-season storm peaks all show signs of delayed 

occurrence across the span of the 52-year Caspar Creek 

data set. The consequence of this delay is less evident. 

Botkin and others (1994) reported that minimum flows in 

November, were strongly correlated with the abundance 

of spring Chinook salmon adults returning to spawn on 

Oregon’s Rogue River three years later. Others have 

correlated fall flows with coho abundance in the nearby 

Noyo River, noting a weak positive relationship between 

juvenile abundance and mean monthly flows for the 

time period between the preceding November 15th and 

January 15th (Stillwater Sciences, 2008). When Caspar 

coho escapement estimates for 2000-2014 were regressed 

against fish-passage flows for November through January, 

the relationship was significant (p= 0.028) only when an 

exceptionally high 2005 abundance estimate was omitted. 

This anomaly may be explained by the exceptional 2002 

return and subsequent favorable ocean conditions during 

the two-year marine life stage of this three-year cohort. 

Gallagher and others (2012) found that marine survival 

was more important to total survival than freshwater 

survival. Brood cycle population dynamics, ocean 

conditions, and freshwater (particularly winter) habitat 

qualities all influence coho abundance. Nonetheless, 

the prospect of delayed onset of fall rains and reduced 

fall flows into the future suggests that coho spawning 

migrations may be increasingly impeded. 

Recent reports detail the formation and persistence of a 

stagnant weather pattern along the west coast during the 

past three winters, including 2014-15. A persistent region 

of atmospheric high pressure nicknamed the “ridiculously 

resistant ridge” has been blamed for the recent California 

drought, leading to forecasts of continued abnormally dry 

weather. Temperatures are warming faster in the Arctic 

than anywhere else in the world. This arctic amplification 

Figure 3—Mean daily flow 1963-1992 and 1993-2012, mean daily average and 30-day running average.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 145

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

has spurred climate scientists to investigate the pathways 

by which arctic changes can influence mid-latitude 

weather and extreme events (Cohen and others 2014). 

Possible linkages include changes in storm paths and 

altered jet stream characteristics, both of which are key 

drivers of mid-latitude weather along the west coast. 

Temporal concentration (intensification) of precipitation 

brought about by altered atmospheric circulation is cause 

for concern not only because extreme events trigger high 

winter flows that negatively impact over-winter salmonid 

survival (Gallagher and others 2012), but also because 

the lack of sufficient fall rainfall may leave adult coho 

unable to enter their natal streams to spawn. Greater 

understanding of these linkages and their effects on 

coastal streams and anadromous fisheries is needed.

FUTURE DIRECTIONS

Caspar Creek is one of several long-term research sites 

providing data for the understanding forest ecosystems 

and management impacts. Because of the length of 

record, consistency of measurements, and use of 

established controls, data from research watersheds are 

invaluable for addressing complex issues of climate 

and hydrology. Reid and Lewis (2011) developed an 

antecedent precipitation model to calculate expected 

flows from the NF in the absence of logging to model 

the effects of altered rainfall and harvest in the Caspar 

Creek watersheds. This approach may prove useful to 

further explore the consequences of hydrologic regime 

shift in this watershed. In addition, it may be useful to 

examine potential water quality and stream temperature 

effects brought about by reduced or delayed fall flows 

using an interdisciplinary approach. Fisheries biologists 

can provide additional insights into the effects of a 

compressed or delayed migration season on coho recovery 

and restoration planning. Other kinds of climatic change 

(for example, temperature increases and altered fog 

frequency) will also influence streamflow and freshwater 

habitat conditions.

The observational study discussed herein does not 

demonstrate a causal link between global climatic trends 

and patterns observed at Caspar Creek. Cause and effect 

may be established only through further monitoring 

and climate modelling advances. Meanwhile, it remains 

critically important to pursue applied and process-based 

research that enhances our understanding of ecosystem 

function and resilience. Forest management and timber 

harvest activities will continue across the forested 

landscapes of the western U.S. Maintaining natural 

processes while utilizing forest products, managing to 

reduce wildfire severity, and ensuring adequate water 

supplies will require strategic thinking, interdisciplinary 

research, and adaptive management. 

Figure 4—Duration of fish-passage flows (85 to 1331 L s-1) expressed as days within flow range 

for North Fork and South Fork and adult coho abundance estimate expressed as tens of fish. 

Only November trends significant (p=0.017 SF, 0.013 NF).
146 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

Figure 5—First fall peak flow, last spring peak flow, and length of storm season by hydrologic year. 

Only first-of-season trend significant (p=0.013).
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 147

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

ACKNOWLEDGMENTS

The Caspar Creek Experimental Watersheds are managed 

cooperatively by the California Department of Forestry 

and Fire Protection and the USFS Pacific Southwest 

Research Station. California Department of Fish and 

Wildlife monitor fish populations. Data compilation and 

map preparation were assisted by Jayme Seehafer, Nathan 

Ernster, and Shawn Headley. Helpful reviews were 

provided by Leslie Reid and Pete Cafferata. 

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climate variability and change in the Pacific Northwest of the 

United States. Journal of Climate. 27(5): 2125-2142.

Botkin, D.; Cummins, K.; Dunne, T.; Regier, H.; Sobel, M.; 

Talbot, L. 1994. Status and future of salmon of western 

Oregon and northern California: findings and options. Report 

No. 8. The Center for the Study of the Environment. Santa 

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Burt, T.P., Howden, N.J.K.; McDonnell, J.J.; Jones, J.A.; 

Hancock, G.R. 2014. Seeing the climate through the trees: 

observing climate and forestry impacts on streamflow using a 

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CDFG (California Department of Fish and Game). 2004. 

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Overland, J.; Jones, J. 2014. Recent arctic amplification and 

extreme mid-latitude weather. Nature Geoscience 7: 627-637

Gallagher, S.P., Thompson, S.; Wright, D.W. 2012. Identifying 

factors limiting coho salmon to inform stream restoration in 

coastal Northern California. California Fish and Game 98(4): 

185-201.

Gallagher, S.P.; Thompson, S.; Wright, D.W. 2014. Coastal 

Mendocino County salmonid life cycle and regional 

monitoring: monitoring status and trends for 2013. 2012-

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and Game Fisheries Restoration Grant Program Grant # 

P0810312. Coastal Watershed Planning and Assessment 

Program, Fortuna, CA. 50 p.

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on coastal watersheds: the Caspar Creek story. May 6, 

1998, Ukiah, CA. USDA Forest Service Pacific Southwest 

Research Station, Albany, CA. General Tech. Rep. PSW 

GTR-168: 1-9

Madej, M.A. 2011. Analysis of trends in climate, streamflow, 

and stream temperature in north coastal California. 

In: Medley, C.N., Patterson, G., and Parker, M.J., eds. 

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in the watersheds: Observing, studying, and managing 

for change. 26-30 September 2011, Fairbanks, AK. US 

Geological Survey Scientific Investigations Report 2011-

5169: 40-45.

Null, S.E.; Veers, J.H.; Mount, J.F. 2010. Hydrologic response 

and watershed sensitivity to climate warning in California’s 

Sierra Nevada. PLoS ONE 5(4): e9932.

Peterson, D.H.; Stewart, I.; Murphy, F. 2008. Principle 

hydrologic responses to climatic and geologic variability in 

the Sierra Nevada, California. San Francisco Estuary and 

Watershed Science, Vol. 6, Issue 1 (February), Article 3.

Reid, L.M.; Lewis, J. 2011. Evaluating cumulative effects of 

logging and potential climate change on dry-season flow 

in a coast redwood forest. In: Medley, C.N., Patterson, G., 

and Parker, M.J., eds. Proceedings of the fourth interagency 

conference on research in the watersheds: Observing, 

studying, and managing for change. 26-30 September 

2011, Fairbanks, AK. US Geological Survey Scientific 

Investigations Report 2011-5169:186-191.

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2014. A hydrogeologic framework for characterizing summer 

streamflow sensitivity to climate warming in the Pacific 

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3693-3710.

Stewart, I.R.; Cayan, D.R.; Dettinger, M.D. 2004. Changes in 

snowmelt runoff timing in Western North America under 

a ‘Business as usual’ climate change scenario. Climatic 

Change 62: 217-232.

Stillwater Sciences. 2008. Examination of long-term trends in 

fish abundance in Little North Fork Noyo River, California. 

Final Technical Memorandum prepared for Campbell 

Timberland Management, LLC. Arcata, CA 95521. 38 p.

Winzler & Kelley Consulting Engineers and Michael Love & 

Associates. 2006. Caspar Creek Fish Passage Improvement 

Project Final Design Report. Unpublished report dated 

December 2006. Prepared for the Trinity County Planning 

Department Natural Resources Division. 39 p.
148 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

IMPACT OF SOIL MOISTURE DEFICIT ON ECOSYSTEM 

FUNCTION ACROSS THE UNITED STATES

Susan Moran, Morgan Ross, Mallory Burns1

The cumulative effect of recent prolonged warm drought on regional ecosystem function 

is still uncertain. Large regions of the United States are experiencing new hydroclimatic 

conditions with extreme variability in climate drivers such as total precipitation, precipitation 

patterns (e.g., storm size, intensity and frequency), and seasonal temperatures. In turn, some 

regions are experiencing prolonged soil moisture deficit, when the average monthly soil 

moisture drops below the record-long mean for an unprecedented number of consecutive 

months. These new conditions are eliciting a variety of short- and long-term responses in 

ecosystem productivity, and thus, generalizations across space and time are rare. Through 

a series of studies using long-term records of USDA experimental watersheds, ranges and 

forests, some cross-biome conclusions have been reached, leading to several consistent 

predictions about ecosystem resilience. A key finding was that soil moisture deficit is a more 

consistent predictor of ecosystem productivity than climate drivers such as precipitation and 

temperature. In fact, ecosystems facing prolonged soil moisture deficit were found to reach 

a threshold associated with recent reports of regional grassland and forest mortality. Such 

thresholds, driven by the recent extended drought, were observed for both water- and lightlimited grasslands in the southern United States. This presentation presents a synthesis of 

the role that soil moisture measurements play in understanding and predicting the functional 

response of ecosystems to climate change. Results are based on multi-location analysis 

of decade-long hydroecological measurements at experimental sites across the United 

States during the early 21st century drought. These results advance our understanding of 

ecosystem responses to complex climate variability, and demonstrate the value of new global 

observations of surface soil moisture with orbiting missions.

1

Susan Moran, Research Hydrologist, USDA Agricultural Research Service, Southwest Watershed Research Center, Tucson, AZ 85719

Morgan Ross, Biological Technician, USDA Agricultural Research Service, Southwest Watershed Research Center, Tucson, AZ 85719

Mallory Burns, Biological Technician, USDA Agricultural Research Service, Southwest Watershed Research Center, Tucson, AZ 85719
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 149

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

TESTING RESILIENCY OF HYDROLOGIC DYNAMICS OF A PAIRED 

FORESTED WATERSHED AFTER A HURRICANE IN ATLANTIC 

COASTAL PLAIN USING LONG-TERM DATA

Devendra Amatya, Herbert Ssegane, Charles Andy Harrison, Carl Trettin1

Hurricanes are infrequent but influential disruptors of ecosystem processes, including 

streamflow and evapotranspiration dynamics in the southeastern Atlantic and Gulf coasts. 

However, literature on hurricane effects on long-term streamflow dynamics is lacking 

in this highly urbanizing region characterized by a poorly drained low-gradient forested 

landscape. Furthermore, the validity of paired watershed approach, often used for quantifying 

effects of land management and land use change on streamflow dynamics, is still poorly 

understood for systems dramatically impacted by the hurricanes. In this long-term study 

on a paired 1st order forested watershed system within the Santee Experimental Forest, 

South Carolina impacted by Hurricane Hugo in 1989, we used streamflow data from10 year 

(1969-1978) for a pre-hurricane (pre-Hugo) period and the most recent 10 years after forest 

regeneration (2004-2013) (post-Hugo period) to examine the effects of the hurricane on paired 

relationships of streamflow dynamics using hydrograph characteristics and the flow frequency 

duration patterns for extreme high and low flows. We tested the hypothesis that the post-Hugo 

paired watershed relationships between the treatment and the control (both with regenerated 

forests since Hugo) for mean storm event hydrograph characteristics (i.e. stormflow volume, 

peak flow rate, time to peak, and runoff coefficients) are not significantly different from the 

pre-Hugo ones, indicating both the resiliency of these coastal forests to the extreme hurricane 

events and the paired approach. We also examined the relationships of the same hydrograph 

characteristics between the control and treatment watersheds observed during the prehurricane annual partial prescribed burning treatment period (1976-81) and the post-Hugo 

treatments of whole tree thinning and burning conducted during 2006-11 for difference in the 

treatment effects. These results have strong implications in using long-term data as a baseline 

reference as well as for applications of the paired watershed approach on this and similar other 

coastal forest systems for assessing land use/land cover change and management impacts.

1

Devendra Amatya, Research Hydrologist, USDA Forest Service, Cordesville, SC 29434

Herbert Ssegane, Postdoctoral Appointee, Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439

Charles Andy Harrison, Hydrologic Technician, USDA Forest Service, Cordesville, SC 29434

Carl Trettin, Soil Scientist, USDA Forest Service, Cordesville, SC 29434
150 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

HYDROLOGICAL EFFECTS OF TROPICAL LAND USE 

MANAGEMENT INCENTIVES: PANAMA CANAL WATERSHED

Fred Ogden, Jefferson S. Hall, Holly Barnard, Robert F. Stallard, Eli Fenichel, Vic 

Adamowicz, Brent Ewers, Ed Kempema, Julian Zhu1

Panama lies in the seasonal tropics and over 85 percent of annual precipitation falls during 

the May-December wet season. Extreme rainfall events near the end of the wet season can 

produce flooding that impact Panama Canal operations. During the December-April dry 

season, occasional water shortages limit the draft of ships passing through the Panama Canal, 

as well as hydropower production. The Smithsonian Tropical Research Institute (STRI) 

Panama Canal Watershed Experiment- Agua Salud Project (ASP) broadly aims to improve 

our predictive understanding of the effects of land-use, land-cover, and land management 

decisions on the provisioning of ecosystem services in the Panama Canal Watershed (PCW) 

and in similar tropical landscapes with saprolitic soils. The hydrological component of the 

STRI-ASP is focused on runoff generation, flow paths, and residence times as affected by 

land-cover and land-use history. We have instrumented 10 watersheds that range in size from 

7 ha to 178 ha, from which we collect high-frequency rainfall, meteorological, runoff, water 

quality, isotopic, and groundwater level data. Our study watersheds have similar topography, 

soil types, and rainfall; the dominant difference between them is land-cover and land-use 

history. Observed effects of land-use/cover and land management include differences in eventscale runoff volumes and peak flow rates, both of which affect flooding, water quality and 

erosion. Over seasonal time scales, we observe that land-use and land-cover also affect base 

flow discharges- an important dry-season ecosystem service. Ultimately, we aim to improve 

the ability of physics-based hydrological models to predict the influence of land-use and landcover on hydrological response in tropical watersheds with saprolitic soils, which represent 

about 70 percent of the tropics. We share data with the Panama Canal Authority to test the 

scalability of our hydrological observations in larger watersheds. While this presentation 

focuses on hydrological processes and observations, our team includes socio-economists 

working to better understand the effectiveness of land-use incentives provided by the Panama 

Canal Authority in the PCW, and ecologists studying a wide-range of other land-cover related 

ecosystem service provisioning including timber production, habitat, and species diversity.

1

Fred Ogden, Cline Distinguished Chair of Engineering, Environment, and Natural Resources in the Department of Civil & Architectural Engineering 

and Haub School of the Environment and Natural Resources, University of Wyoming, Laramie, WY 82071

Jefferson S. Hall, Staff Scientist, Smithsonian Tropical Research Institute, Panama City, Panama

Holly Barnard, Assistant Professor of Geography, INSTAAR, University of Colorado, Boulder, CO 80309

Robert F. Stallard, Research Hydrologist, US Geological Survey, Boulder, CO 80309

Eli Fenichel, Assistant Professor, Yale School of Forestry and Environmental Studies, New Haven, CT 06511

Vic Adamowicz, Professor, Department of Resource Economics & Environmental Sociology, Univsity of Alberta, Edmonton, AB, Canada T6G2P5

Brent Ewers, Associate Professor, Department of Botany, University of Wyoming, Laramie, WY 82071

Ed Kempema, Postdoctoral Researcher, Department of Geology and Geophysics, University of Wyoming, Laramie, WY 82071

Julian Zhu, Professor of Civil Engineering, Department of Civil and Agricultural Engineering, University of Wyoming, Laramie, WY 82071
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 151

New Insights into Studies on Long-term Experimental Watersheds to Address Contemporary Emerging Issues (Part 2)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

IDENTIFICATION OF TEMPORAL PATTERNS OF LONG-TERM 

HYDROLOGICAL SIGNALS IN LOWER MISSISSIPPI RIVER BASIN 

USING WAVELET ANALYSIS

Ying Ouyang1

Estimates of surface hydrological characteristics in watershed ecosystems are essential to 

climate change assessment, water supply planning, water quality protection, ecological 

restoration, and water resources management. Wavelet analysis is one of the major data 

analysis methods developed during the last couple decades and has been proved to be a 

very successful technique for signal process, meteorology, oceanography, and water quality 

assessment. Using wavelet analysis, we analyzed the temporal patterns of hydrological 

signals, including precipitation, stream flow, and air temperature, in the Lower Mississippi 

River Basin (LMRB). The long-term (> 60 years) measured hydrological data used in the 

study were obtained from USGS surface water monitoring stations located in the headwater 

upstream areas (or quasi-pristine areas) within the LMRB. Our specific objectives were to: 

(1) identify the decadal temporal patterns of precipitation, stream flow, and air temperature in 

conjunction with the past climate change impacts in the LMRB; and (2) estimate the annual 

and seasonal temporal patterns of stream flow associated with recurrence intervals of low flow 

in the LMRB. Results and conclusions from this study will be presented.

1

Research Hydrologist, USDA Forest Service, Southern Research Station, Center for Bottomland Hardwoods Research, Mississippi State, MS 39762

Assessments for Watershed Management
154 Headwaters to Estuaries: Advances in Watershed Science and Management

Assessments for Watershed Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

INTEGRATING TIDAL AND NONTIDAL ECOLOGICAL ASSESSMENTS

Mark Southerland and Roberto Llansó1

The Maryland Department of Natural Resources (DNR) has a long history of conducting rigorous 

assessments of ecological conditions in both tidal and nontidal waters. The Long-Term Benthic 

(LTB) Monitoring Program and the Maryland Biological Stream Survey (MBSS) both use 

reference-based indicators of benthic invertebrate communities to provide areawide estimates of 

condition status and trends. While these programs are comparable in approach, their assessments 

have remained independent. The management goals for state agencies, U.S. Environmental 

Protection Agency (EPA), National Oceanic and Atmospheric Administration (NOAA), and other 

agencies are increasingly watershed based and would benefit from an integration of tidal and 

nontidal assessments. Small-scale studies have demonstrated that upstream land uses can have 

profound effects on both nontidal and tidal waters downstream, but the prevalence of these effects 

over large areas have not been effectively studied. We analyzed two decades’ worth of synoptic 

data on the condition of Maryland tidal and nontidal waters to determine the range of concurrence 

in condition assessments between upstream and downstream waters. The results indicate that 

a consistent report card of ecological condition across tidal and nontidal waters is practicable, 

and has implications for improving our understanding of the dynamics of freshwater tidal and 

nearshore ecosystems.

As an example, we present an assessment of the Upper Eastern Shore of the Chesapeake Bay in 

Maryland. The Upper Eastern Shore is predominantly agricultural. Forested areas account for 

31 percent of land cover, 8 percent of the basin is comprised of urban lands, and development is 

low intensity. As of 2000, agricultural sources contributed 72 percent to the basin’s total nitrogen 

load, and 67 percent to the phosphorus load. Agriculture was also the largest source of sediment, 

contributing 88 percent of the basin’s sediment load. The first 2 rounds of the MBSS (1995-1997, 

2000-2004) showed stream benthic condition failing over 50 percent of the upper Chester River 

primary sampling unit (salmon shade), whereas a majority of the basin area had moderately good 

stream benthic condition (light green shade) (Fig. 1). The Upper Chester River exhibited the 

worst water quality in the region. An increasing trend in total nitrogen concentration was detected 

in the Upper Chester River and poor status was observed for chlorophyll a, total suspended 

solids, total nitrogen, total phosphorus, and Secchi depth. Over the same time period, benthic 

community condition was worst in the upper tidal fresh portion of the Chester River (100 percent 

fail), moderately good in the middle oligohaline portion (33 percent fail), and degraded in the 

lower mesohaline portion (60 percent fail). Except for the Northeast River, the other major basin 

tributaries had good to moderately good tidal benthic community condition (Fig.1). 

The results of LTB agree well with those of the MBSS, and can be used to identify areas impacted 

by high nutrient and sediment runoff. Additionally, LTB shows the influence of the Chesapeake 

Bay mainstem. Low dissolved oxygen events are common and severe in the Maryland mainstem. 

Anoxia is a common feature of the mid-bay deep channel, and hypoxia typically affects benthic 

communities in mainstem waters. Eastern Bay and the Lower Chester River reflect benthic 

community condition influenced by mainstem hypoxia and, therefore, provide contrast to MBSS 

results (Fig. 1). While nontidal waters are affected by stressors in the watershed, tidal waters show 

upstream and downstream sources of stress. The integration of tidal and nontidal assessments thus 

provides a holistic picture of ecosystem condition.

1

Mark Southerland, formerly Director of Ecological Sciences/Applications, Versar, Inc., Columbia, MD 21045; now, Vice President, AKRF Inc., 

Hanover, MD 21076 

Roberto Llansó, Senior Scientist, Versar, Inc., Columbia, MD 21045 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 155

Assessments for Watershed Management

Figure 1—Maryland Upper Eastern Shore Basin tidal (rivers and bays) and nontidal (primary MBSS 

sampling units) assessment of benthic invertebrate condition. Shown is the percent area failing the 

LTB or MBSS benthic index of biotic integrity, 1995-1997 and 2000-2004.

Legend

Sample locations

Percent Fail

< 25

25 - 49

50 - 74

>= 75

Not evaluated

10 Miles  ̧

Bohemia River

Sassafras River

Chester River

Elk River

Eastern Bay

North East River

Map

Detail

Chesapeake Bay
156 Headwaters to Estuaries: Advances in Watershed Science and Management

Assessments for Watershed Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

DEVELOPMENT OF AN INTEGRATED ECOSYSTEM MODEL TO 

DETERMINE EFFECTIVENESS OF POTENTIAL WATERSHED 

MANAGEMENT PROJECTS ON IMPROVING OLD TAMPA BAY

Edward T. Sherwood, Holly Greening, Lizanne Garcia, Kris Kaufman, Tony 

Janicki, Ray Pribble, Brett Cunningham, Steve Peene, Jim Fitzpatrick, 

Kellie Dixon, and Mike Wessel1

Abstract—The Tampa Bay estuary has undergone a remarkable ecosystem recovery since the 1980s despite continued 

population growth within the region. However during this time, the Old Tampa Bay (OTB) segment has lagged behind the 

rest of the Bay’s recovery relative to improvements in overall water quality and seagrass coverage. In 2011, the Tampa 

Bay Estuary Program, in partnership with the Southwest Florida Water Management District, began development of an 

integrated set of numerical and empirical modeling approaches to evaluate management actions to improve the ecology of 

the OTB estuarine segment. The goal was to integrate watershed, hydrodynamic, water/sediment quality, and ecological 

models (light and biota) to simulate changes in OTB ecology in response to the future implementation of large-scale 

management actions. The potential management actions evaluated: 1) completely diverting stormwater/freshwater input 

from a portion of the subwatershed that historically drained to the Gulf of Mexico, 2) diverting 100 percent of the directly 

discharged advanced wastewater treatment effluent to OTB from the subwatershed, 3) physically altering causeways along 

road expanses that intersect OTB, 4) reducing stormwater nutrient loads by 25 percent throughout the subwatershed, and 

5) various combinations of these actions, as well as, other secondary management actions. The integrated set of models 

were used to evaluate the net environmental benefits to OTB’s water quality (light environment and dissolved oxygen 

conditions), sediment quality (reduced accumulation of organic-rich sediments), potential expansion of seagrasses, and 

benthos/nekton habitat suitability. Based upon this evaluation, management actions that produced the greatest simulated 

improvements relative to costs are being considered for further evaluation in the OTB segment and subwatershed.

INTRODUCTION

The Tampa Bay estuary has been recognized as one of 

the few national and worldwide examples of a coastal 

ecosystem in recovery despite continued urbanization and 

population growth within its watershed (Greening et al. 

2014). Baywide seagrass coverage continues to expand 

and now has approached levels commensurate to the 

extent last observed in the 1950s, a recovery goal set by 

the community through the Tampa Bay Estuary Program’s 

(TBEP) Comprehensive Conservation and Management 

Plan (TBEP 2006). However, periodic setbacks have been 

observed in some of the Bay’s extent, particularly in the 

Old Tampa Bay (OTB) management segment (Figure 1). 

Compared to other areas of the Bay, OTB’s recovery has 

lagged. The primary ecological issues of concern in OTB 

leading up to the development of this project included:

• organic sediment (muck) accumulation in the upper 

portions of OTB,

• limited seagrass expansion in distinct, poor 

circulation areas of OTB, 

• alteration of freshwater inflows from managed 

channels discharging to OTB, and

• the periodic occurrence of nuisance algal blooms 

(Pyrodinium bahamense).

1

Edward T. Sherwood, Senior Scientist, Tampa Bay Estuary Program (TBEP), St. Petersburg, FL 33701 

Holly Greening, Executive Director, TBEP, St. Petersburg, FL 33701 

Lizanne Garcia, Senior Environmental Scientist, Southwest Florida Water Management District (SWFWMD), Tampa, FL 33637

Kris Kaufman, Senior Environmental Scientist, SWFWMD, Tampa, FL 33637

Tony Janicki, President, Janicki Environmental Inc., St. Petersburg, FL 33704

Ray Pribble, Senior Vice President, Janicki Environmental, Inc., St. Petersburg, FL 33704

Brett Cunningham, Water Resources Director, Jones Edmunds & Associates, Inc., Gainesville, FL 32641

Steve Peene, Vice President, ATM, Inc., Tallahassee, FL 32308

Jim Fitzpatrick, Senior Professional Associate, HDR|Hydroqual, Mahwah, NJ 07495

Kellie Dixon, Senior Scientist, Mote Marine Laboratory, Sarasota, FL 34236

Mike Wessel, Vice President, Janicki Environmental Inc., St. Petersburg, FL 33704
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 157

Assessments for Watershed Management

In response, the TBEP, in partnership with the Southwest 

Florida Water Management District (SWFWMD), sought 

to develop an integrated ecosystem model to determine 

potential management actions that could further enhance 

OTB’s recovery and address the primary issues outlined 

above. The integrated model envisioned, included the 

development of a linked watershed, bay hydrodynamic, 

water/sediment quality, and set of ecological models 

(biota and seagrass suitability). This new tool would 

then be used to simulate the net environmental benefits 

of potential, large-scale management actions relative 

to baseline conditions in OTB. Because much has been 

done in the Tampa Bay region to kick-start the Bay’s 

recovery (e.g., wasterwater treatment plant upgrades, 

enhanced stormwater regulations, residential fertilizer use 

ordinances, etc.), the models were intended to simulate 

actions that would require significant investment and buyin from the region in order to implement. Such actions as 

bridge/causeway infrastructure modifications, modifying 

managed freshwater inflows, and continued wastewater/

stormwater infrastructure improvements were considered. 

METHODS

The overall project was broken into five discrete, serial 

tasks. Task 1 included the development of 10 management 

actions that were hypothesized to potentially improve 

OTB’s condition. Development of the management 

actions enlisted support and feedback from the Tampa 

Bay resource management community through a series 

of stakeholder meetings conducted in 2011-2012. Task 

2 included the assimilation of available data sources 

for development of an integrated set of models and 

identification of potential data gaps that would be needed 

to be filled to fully develop the modeling system. Task 3 

involved generation of a Model Development Plan and a 

US Environmental Protection Agency (USEPA) approved 

quality assurance project plan (QAPP). Task 4 included 

the actual development, calibration and validation of 

the integrated model system over a 2000-2009 baseline 

period relative to available monitoring datasets. Task 

5 simulated the net environmental benefits of the 10 

identified management actions from Task 1 under the 

integrated set of models relative to baseline (2000-2009) 

conditions in OTB. This last task further prioritized the 

10 potential management actions relative to their overall, 

anticipated implementation costs. Descriptions of each 

of the modeling components selected for use under this 

project follows.

Watershed Model

The Integrated Northern Tampa Bay (INTB) Model 

was deemed best suited for the watershed modeling 

component of the OTB integrated model system. INTB 

couples HSPF and MODFLOW, simulating surface waterground water processes and their interactions for uplands 

and water bodies (Geurink and Basso, 2013). The INTB 

is used by Tampa Bay Water and SWFWMD for water 

supply planning in the region.

Bay Hydrodynamic Model

ECOMSED was selected as the hydrodynamic model, 

as there was an existing ECOMSED model application 

for the entire spatial domain of Tampa Bay. While the 

grid resolution and focus on OTB was not sufficient 

for this project, the experience and knowledge gained 

from previous studies aided in the development of the 

OTB application of ECOMSED. Another key factor in 

this selection was the existing model code that directly 

linked ECOMSED to the chosen bay water quality model 

(RCA).

Bay Water Quality Model

This component of the integrated model system was to be 

used to assess the effectiveness of management actions 

Figure 1—Overview map highlighting the Tampa Bay 

watershed, Old Tampa Bay watershed, watershed 

model domain (INTB), and hydrodynamic/water quality 

model domains.
158 Headwaters to Estuaries: Advances in Watershed Science and Management

Assessments for Watershed Management

towards improving water quality, water clarity, and the 

potential for expanding seagrass coverage. Given the 

factors that influence seagrass growth and survival, the 

resultant bay water quality model was required to relate 

nutrients, suspended solids, and color to phytoplankton 

biomass and available light, utilizing advective and tidal 

linkages through the chosen hydrodynamic model. The 

RCA model code was selected. Familiarity with the 

model code was important to allow modifications or 

enhancements as necessary (i.e., the addition of CDOM, 

groundwater loadings, and benthic algae dynamics) and 

so that model calibration/verification could be performed 

more efficiently. The RCA model has been in existence 

for more than 20 years, has a proven track record, and 

has pre- and post-processing tools applicable under this 

project.

Ecological Model Components

An Optical Model component was used to predict water 

clarity from RCA outputs at suitable spatial and temporal 

scales with respect to seagrasses. The capability of modeling the spectral characteristics of light, rather than just as 

percent photosynthetically active radiation (percent PAR), 

allowed additional assessments for determining potential 

areas where seagrass coverage could increase/decrease as 

a result of management alternatives being implemented. 

The ability to model spectral distributions of light was 

key to the evaluation. The recommended Optical Model 

for the OTB integrated model system was the empirical 

optical model originally developed by Kirk (1981).

A secondary ecological model was also developed. The 

Environmental Favorability Function (EFF: Real et al., 

2006), a derivative of logistic regression, was selected to 

quantify the effects of changes in water quality on fishes 

and benthic macroinvertebrates in OTB. The advantages 

of using the EFF model over standard logistic regression 

includes reducing prediction bias due to differences in 

taxa prevalence and the ability to directly compare taxa 

with different presence/absence ratios. The goal of using 

the EFF model was to describe changes in environmental 

favorability under a set of environmental conditions as 

predicted by the ECOMSED and RCA models.

Net Environmental Benefit (NEB) Analysis

The predicted results from each management action 

simulation using the integrated model (a model run) 

were compared to the baseline period (i.e., 2000-2009) 

for various, a priori key ecological attribute (KEA) 

outputs from each of the model components. For 

each management scenario, a 10-year mean KEA was 

compared to the 10-year mean KEA over the Baseline, 

and a score was calculated. The score for each KEA 

has been defined such that a positive score represents a 

potential benefit (a desirable outcome) and a negative 

score indicates a potential decline (an undesirable 

outcome) relative to the Baseline condition for each 

KEA. The NEB scores for each KEA were calculated 

and summarized at several spatial scales including three 

subareas that related to the original issues of concern in 

OTB.

RESULTS & DISCUSSION

Model Calibration and Skill Assessments

Following initial construction of each of the model 

components, all models were calibrated to the observed 

conditions during the 2000-2009 period. Model 

calibration refers to the adjustment of model coefficients 

and model resolution in order to minimize the overall 

error in simulating the variables of interest over the full 

range of hydrologic and meteorological conditions that 

occurred during the 2000-2009 period. The effectiveness 

of the model calibration was then assessed using various 

skill assessments and diagnostics. The goal was to 

minimize the overall model error for the full simulation 

period, with specific focus on OTB. A full description 

of the model calibration and skill assessment can be 

found in Janicki Environmental, Inc. (2014). Model 

skill assessment included comparisons error of variables 

of interest with a set of predefined values (i.e., skill 

assessment criteria). Model skill assessment included 

both qualitative evaluations (i.e., time series plots, contour 

plots, etc.) and quantitative evaluations using metrics 

(e.g., relative error, root mean square error, correlation 

coefficients) of model output in comparison to observed 

conditions.

The following skill assessment results were obtained for 

each of the modeling components under this project:

• Watershed Model – all seven (7) of the criteria were 

met;

• Bay Hydrodynamic Model – eighteen (18) of the 

twenty-four (24) criteria were met; 

• Bay Water Quality Model – thirty-two (32) of the 

forty-eight (48) criteria were met; 

• Optical Model – seven (7) of the eight (8) criteria 

were met;

• EFF Models – benthos – six (6) of the eight (8) 

criteria were met; fish – nine (9) of the eleven (11) 

criteria were met.

Net Environmental Benefit Analysis

Muck accumulation in upper OTB--Outputs from the Bay 

hydrodynamic and water quality models from the upper 

portions of OTB were used to assess potential changes 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 159

Assessments for Watershed Management

in sediment muck accumulation. The KEAs that are 

most relevant to muck accumulation included: salinity 

and water age (ECOMSED outputs); organic carbon 

content in the sediments (RCA output); chlorophyll-a, 

total nitrogen, and dissolved inorganic nitrogen in the 

water column (RCA output).The management scenario 

that resulted in the highest NEB score relative to the 

muck accumulation issue was Scenario 9 – the combined 

nonpoint (25 percent) and point source (100 percent) 

reduction management action. Other positive scores were 

found for those scenarios that included either reduced 

flows from Lake Tarpon or other nutrient load reductions. 

The nonpoint source reduction scenario (2) and the 

combined 100 percent Lake Tarpon Outfall Reduction 

and causeway alterations scenario (10) also resulted in 

relatively high NEB scores.

In addition to the net environmental benefit analysis, the 

rate of organic carbon deposition was also examined. 

Reducing the rate of deposition is necessary to achieve 

any reduction in the amount of muck as the amount of 

muck at any point in time is a function of the rate of 

deposition and the rate of decomposition of the deposited 

organic carbon. 

Table 1 presents a comparison of the total mass of organic 

carbon (tons) deposited in upper OTB over the 10-year 

model period (2000-2009) under the Baseline condition 

and each of the management action scenarios examined. 

Scenarios 1 and 10 (100 percent Lake Tarpon discharge 

diversion scenarios) resulted in large reductions in organic 

carbon deposition. The combined nonpoint and point 

source reductions (Scenario 9) also resulted in relatively 

high reductions in organic carbon deposition in that 

portion of OTB.

Limited Seagrass Recovery—Limited seagrass expansion 

has occurred in several areas of OTB; however, results 

presented here are summarized for the entirety of OTB. 

The KEAs used to calculate these NEB scores were: 

percent PAR (Optical Model output), colored dissolved 

organic material (CDOM, RCA output), chlorophyll-a 

(RCA output), total suspended solids (RCA output), and 

area with adequate light (Optical Model output).

The highest NEB score was recorded for the combined 

nonpoint and point source reduction management action 

(Scenario 9) (Fig. 2). The nonpoint source reduction 

management action (Scenario 2), the point source load 

reduction management action (Scenario 3), and the 

combined 100 percent Lake Tarpon Outfall Reduction and 

causeway alterations management action (Scenario 10) 

also resulted in relatively high NEB scores.

Table 2 presents comparisons of the area with adequate 

light to support seagrass between the Baseline and each 

management action scenario. The values presented are 

the resulting adequate light acreages in Year 10 of the 

10-year modeling period (2000-2009). Therefore, these 

values reflect the response to the cumulative changes in 

the nutrient loading and other management actions over 

that 10-year period. 

Nuisance Algal Blooms—The project team determined 

that the issue of concern relating to the occurrence of 

nuisance algal blooms in OTB could not be adequately 

addressed using the existing model outputs. Additional 

data collection efforts were recommended to better understand the life history, bloom initiation and distributions of 

the primary (Pyrodinium bahamense) alga of concern in 

this region. The TBEP is considering additional studies to 

address these information gaps on the alga species. 

Table 1—Total mass of organic carbon deposition to upper Old Tampa Bay (OTB) over the 10-year model period 

relative to the Baseline and each scenario run with gross and percent differences between these mass estimates. 

Positive differences indicate improvements in potential muck accumulation in this focus area.

Management Action Scenario Baseline

(tons)

Scenario

(tons)

Difference

(tons)

 Difference 

(%)

1-100% diversion of Lake Tarpon infl ow 1,516,342 1,308,844 207,498 13.7

2-Gross 25% reduction in OTB nonpoint source loads 1,516,342 1,405,782 110,560 7.3

3-100% reduction in point source discharges to OTB 1,516,342 1,401,651 114,691 7.6

4-Alterations to Courtney Campbell Causeway 1,516,342 1,509,742 6,600 0.4

6-Alterations to Howard Frankland Bridge & Causeway 1,516,342 1,518,492 -2,150 -0.1

7-50% diversion of Lake Tarpon infl ow 1,516,342 1,440,301 76,041 5.0

8-Combined Scenarios 6 & 7 1,516,342 1,440,360 75,982 5.0

9-Combined Scenarios 2 & 3 1,516,342 1,322,157 194,184 12.8

10-Combined Scenarios 1, 4 & 6 1,516,342 1,306,755 209,586 13.8
160 Headwaters to Estuaries: Advances in Watershed Science and Management

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 Table 2—Comparison of the number of acres with adequate light to support seagrass after a 10-year model run 

period (2000-2009) under the Baseline and each scenario with gross and percent differences between these areal 

estimates. Positive differences indicate improvements in the areal light conditions supportive of seagrass growth 

throughout Old Tampa Bay (OTB).

Management Action Scenario Baseline

(acres)

Scenario

(acres)

Difference

(acres)

 Difference 

(%)

1-100% diversion of Lake Tarpon infl ow 10,558 11,101 543 5.1

2-Gross 25% reduction in OTB nonpoint source loads 10,558 10,791 233 2.2

3-100% reduction in point source discharges to OTB 10,558 10,774 216 2.0

4-Alterations to Courtney Campbell Causeway 10,558 10,497 -61 -0.6

6-Alterations to Howard Frankland Bridge & Causeway 10,558 10,543 -15 -0.1

7-50% diversion of Lake Tarpon infl ow 10,558 10,706 148 1.4

8-Combined Scenarios 6 & 7 10,558 10,728 170 1.6

9-Combined Scenarios 2 & 3 10,558 11,491 933 8.8

10-Combined Scenarios 1, 4 & 6 10,558 11,191 633 6.0

Figure 2—Overall results of combined net environmental benefit (NEB) analyses across the entirety 

of OTB relative to the 10 management action scenarios simulated under this project. Positive and 

negative scores relate to positive and negative benefits, respectively.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 161

Assessments for Watershed Management

Implementation Cost Considerations

Muck accumulation in upper OTB—For each priority 

issue, a comparison of the NEB scores relative to the 

costs to potentially implement the management actions 

was made. Figure 3 displays the NEB ranking for each 

of the scenarios along the y-axis (higher is better), and 

the relative cost ranking along the x-axis, for the issue of 

muck accumulation in Safety Harbor. Data points also 

indicate the relative permitting constraints: High (H); 

Medium (M); and Low (L).

Scenario 9, the combined nonpoint (25 percent) and 

point source (100 percent) reduction management action, 

resulted in the highest NEB with a modest permitting 

constraint, although at the highest implementation cost. 

The nonpoint source reduction scenario (2) also returned a 

high NEB ranking with a modest permitting constraint at 

a somewhat lower cost.

Limited Seagrass Recovery—Figure 4 displays the NEB 

ranking for each of the scenarios along the y-axis, and the 

relative cost ranking along the x-axis for the priority issue 

of limited seagrass expansion in two problematic areas 

in Old Tampa Bay (Feather Sound region and northwest 

Hillsborough County drainage areas). 

As was observed with the muck accumulation issue, 

Scenario 9, the combined nonpoint (25 percent) and 

point source (100 percent) reduction management action, 

resulted in the highest NEB with a modest permitting 

constraint, although at the highest implementation cost 

for promoting more seagrass expansion in select areas 

of OTB. The nonpoint source reduction scenario (2) also 

returned a high NEB ranking with a modest permitting 

constraint at a somewhat lower cost, and the point source 

load reduction scenario (3) resulted in the same NEB 

ranking at an even lower cost.

CONCLUSIONS

An integrated set of watershed, bay hydrodynamic, bay 

water quality, and bay ecological models was developed 

under this project. The resulting KEA outputs from 

each of the modeling components were individually 

assessed to determine a NEB score, and pertinent scores 

were summarized according to priority issues and 

areas in OTB. The resulting NEB analyses indicated 

that combined efforts to reduce point source (primarily 

domestic wastewater treatment plants) and nonpoint 

source (primarily urban/suburban stormwater inputs) 

nutrient inputs to OTB’s watershed and embayment would 

have the greatest overall benefit to ecology, however 

Figure 3—Comparison of pertinent net environmental benefit (NEB) scores for each management action 

scenarios (#) relative to potential implementation cost rankings for the muck accumulation issue in upper 

Old Tampa Bay (OTB).
162 Headwaters to Estuaries: Advances in Watershed Science and Management

Assessments for Watershed Management

Figure 5—Localized differences (scenario - baseline as a percentage, middle panel) in chlorophyll-a (μg/L) 

conditions in OTB simulated from the 100% Lake Tarpon Outfall diversion scenario (1, right panel) relative to the 

calibrated, baseline condition (left panel) averaged over the 2000-2009 period.

Figure 4—Comparison of pertinent net environmental benefit (NEB) scores for each management action 

scenarios (#) relative to potential implementation cost rankings for seagrass recovery in two areas of Old 

Tampa Bay (OTB), Feather Sound region and northwest Hillsborough drainage areas.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 163

Assessments for Watershed Management

at an extremely high implementation cost. Localized 

issues (e.g., muck accumulation in upper OTB) would 

also benefit from localized management actions (e.g., 

reductions in Lake Tarpon outfall discharges, Figure 

5) at lower costs; however, overall benefits to OTB’s 

entire ecology were less prominent. Physical alterations 

(e.g., causeway modifications) also showed similar 

localized benefits to specific issues; however causeway 

modifications appeared to have minor or negligable 

ecological benefits in OTB. In addition, causeway 

modification benefits also appeared to be better enhanced 

when combined with other actions (e.g. reducing Lake 

Tarpon outfall discharges, point source/nonpoint source 

reductions), adding to potential implementation costs. As 

resource managers in the region begin to plan for further 

ecosystem recovery in OTB, the modeling results from 

this assessment and further application of the integrated 

model system can be used to weigh benefits to the 

environment versus costs to implement actions in order 

to promote the most cost-effective solutions to improve 

OTB’s ecology. 

LITERATURE CITED

Kirk, J.T.O. 1981. A Monte Carlo study of the nature of the 

underwater light field in, and the relationships between 

optical properties of turbid yellow waters. Australian Journal 

Marine Freshwater Research 32: 517–532.

Geurink, J.; Basso, R. 2013. Development, calibration, and 

evaluation of the Integrated Northern Tampa Bay Hydrologic 

Model. Prepared for Tampa Bay Water and the Southwest 

Florida Water Management District.

Greening, H.S.; Janicki, A.; Sherwood, E.T.; [and others]. 

2014. Ecosystem responses to long-term nutrient 

management in an urban estuary: Tampa Bay, FL, USA. 

Estuarine, Coastal and Shelf Science. 151:A1-A16. DOI: 

10.1016/j.ecss.2014.10.003.

Janicki Environmental, Inc. 2014. Old Tampa Bay Integrated 

Model Development Project. Task 4 - Development of 

Calibrated Models for the Old Tampa Bay Integrated Model 

System. Prepared for the Tampa Bay Estuary Program, St. 

Petersburg, FL. https://www.tbeptech.org/DATA/OTB_

Evaluation/Task_4/OTB_Task_4_Report_Final_06142014.

pdf . [Date accessed: March 2015].

Real, R.A.; Barbosa, M.; Vargas, J.M. 2006. Obtaining 

favorability functions from logistic regression. 

Environmental Ecological Statistics. 13:237-245.

Tampa Bay Estuary Program. 2006. Charting the Course: The 

Comprehensive Conservation & Management Plan for 

Tampa Bay, St. Petersburg, FL. http://www.tbep.org/about_

the_tampa_bay_estuary_program-charting_the_course_

management_plan-download_charting_the_course.html. 

[Date accessed: March 2015].
164 Headwaters to Estuaries: Advances in Watershed Science and Management

Assessments for Watershed Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATERSHED PLANNING, IMPLEMENTATION AND ASSESSMENT: 

THE MAY RIVER WATERSHED ACTION PLAN CASE STUDY

Kimberly W. Jones, Christopher L. Ellis, Jeremy S. Ritchie1

Abstract—Prior to exponential growth in the early to mid-2000s, the Town of Bluffton, SC was one square mile; as of 

2015, it is approximately 55 square miles. Associated with this growth was a shellfish harvesting closure for nearly onethird of the May River in 2009. The Town and its partners developed and began to implement the May River Watershed 

Action Plan in 2011. The plan is a “living document” allowing for the incorporation of new information and technology 

as well as modifications based upon its impact on water quality. The continuous evaluation of the success of any 

watershed management plan is crucial to keeping a plan relevant. Utilizing an adaptive management logic model strategy 

provides managers a tool to effectively assess and modify their watershed management plan in response to ever-changing 

environmental conditions, an increasing technical knowledge base, increasing implementation costs, and decreasing 

resources, in the face of a constant demand for action and favorable results. This case study provides an example of 

utilizing an adaptive management logic model to initially evaluate a watershed plan. 

INTRODUCTION

The May River (HUC 3060110-03) is a tidal embayment 

located in southern Beaufort County, SC. The Town 

of Bluffton (Town), sitting alongside the river, has 

had strong ties to it since its establishment in 1825. 

Commercial shellfish harvesting has historically been, 

and still remains, a significant component of the 

economy, tradition and community character of the 

Town. Additionally, the aesthetics and views of the May 

River increase the popularity of Bluffton for residential, 

commercial, and tourist visitation growth, tying the 

Town’s economic conditions directly and indirectly to 

the river. For these reasons, the May River has been 

designated an Outstanding Resource Water (ORW) by the 

South Carolina Department of Health and Environmental 

Control (SCDHEC 2012).

Rising popularity of the area resulted in the Town’s 

incorporated limits expanding from one square mile in 

1987 to approximately 55 square miles today. Between 

2000 and 2010 the Town’s population increased by 883 

percent from 1,275 to 12,530. The number of housing 

units rose from 501 to 5,393 during the same time, 

an increase of 976 percent (U.S. Census Bureau 2000 

and 2010). 

With the rapid increase in population and development 

came rising fecal coliform levels in the May River’s 

environmentally sensitive headwaters, resulting in nearly 

one-third of the river being closed to shellfish harvesting 

in 2009. Today, the May River is included in the 

approximately 1,100 Total Impairments listed among 920 

Impaired Sites within the state of South Carolina’s Clean 

Water Act Section 303(d) listed waterbodies (SCDHEC 

2014). Thus, the following case study of the development, 

implementation and initial evaluation of the May River 

Watershed Action Plan is pertinent for both coastal and 

interior water resource managers whose goal is to develop 

a comprehensive approach to prevent, respond to, or 

to evaluate the impacts of their plans on water quality 

impairments. 

Program Background

The May River is located within the jurisdictions of 

the Town of Bluffton and Beaufort County, where it 

bisects the Town’s jurisdiction (Fig. 1). With annexation 

and substantial residential development, land use 

was converted from mostly pine crops to residential 

subdivisions and an associated increase in impervious 

surface and stormwater runoff. In 2007, SCDHEC 

reported to the Town that fecal coliform levels in the 

headwaters of the May River were increasing. In 2008, 

in response to this increase, the Environmental Protection 

Agency (EPA) and SCDHEC designated the May River 

as a priority and threatened watershed, thus making 

it eligible for EPA Clean Water Act Section 319 grant 

funding. In 2009 the Town developed an initial watershed 

1

Kimberly W. Jones, M.S., Director of Department of Engineering and Public Works, Town of Bluffton, Bluffton, SC 29910

Christopher L. Ellis, Ph.D., Social Scientist, NOAA Office for Coastal Management, Charleston, SC 29405

Jeremy S. Ritchie, P.E., CSPR, Assistant Director of Engineering and Public Works, Town of Bluffton, Bluffton, SC 29910
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 165

Assessments for Watershed Management

plan which was awarded an EPA 319 grant by SCDHEC 

for implementation to reduce the fecal coliform levels. 

Despite initial implementation of that plan, in the fall of 

2009 the river received its first-ever shellfish harvesting 

classification down-grade in the headwaters due to high 

fecal coliform levels. 

While recreational contact is still permissible, rising fecal 

coliform levels can be an indicator of the deterioration 

of the overall health of a watershed since an increase in 

this pollutant is often associated with an increase in other 

pollutants including sediments, nutrients, and potentially 

viruses. In response to this degradation of water quality, 

the Town voluntarily committed to take action to augment 

the existing 319-funded watershed plan to create an 

updated, comprehensive May River Watershed Action 

Plan (Action Plan). 

The goal of the Action Plan is to create a program 

which includes both structural and nonstructural Best 

Management Practices (BMPs) projects to restore 

shellfish harvesting within the headwaters of the May 

River and to protect the river from future degradation. 

Adapting the guidelines found in the “Handbook for 

Developing Watershed Plans to Restore and Protect Our 

Waters” (EPA 2008), Town staff worked for nearly a year 

with consultants, Beaufort County, and local stakeholders 

to develop the Action Plan (AMEC 2011). The Bluffton 

Town Council adopted the May River Watershed Action 

Plan by Resolution in November 2011 as a program 

for stormwater management and May River watershed 

restoration and protection. 

With the Action Plan program providing direction to 

the Town’s stormwater management and water quality 

improvement projects for nearly three years, a number 

of the program’s projects have been implemented or are 

on-going. Currently, a simultaneous effort is being made 

to continue with project implementation while objectively 

evaluating the impact of these projects on improving 

water quality. As a result of this evaluation, Town staff can 

make adjustments to the Action Plan program as needed 

and re-evaluate its impact at regular intervals in the future. 

This iterative approach is known as adaptive management 

(EPA 2008) and is depicted in Figure 2. Implementing 

an adaptive management strategy provides managers 

a tool to effectively assess and modify their watershed 

management plans in response to ever-changing 

environmental conditions, an increasing technical 

knowledge base, increasing implementation costs, and 

decreasing funding sources, while under a constant 

demand for action and positive results.

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BLUFFTON

REGIONAL

MAP

Town of Bluffton Beaufort County, SC

Prepared by Engineering Dept.

Scale in Miles

Stormwater Division

DISCLAIMER:

This map was created by the Engineering Department

of the Town of Bluffton and is solely intended

to be used as a graphical representation for the

Town of Bluffton. The GIS maps and data distributed

by the Engineering Department of the Town of

Bluffton are derived from a variety of public and

private sector sources considered to be dependable,

but the accuracy, completeness and currency thereof are

not guaranteed. The Town of Bluffton makes no warranties,

expressed or implied, as to the accuracy, completeness,

currency, reliability, or suitability for any particular purpose

of information or data contained in or generated from the

town’s Geographic Information Systems database.

Additionally, the Town of Bluffton or any agent, servant,

or employee thereof assume no liability associated

with the use of this data, and assume no responsibility

to maintain it in any matter or form.

LEGEND JURISDICTIONAL

Hardeeville

Jasper

County Hilton Head

Island

Bluffton

Town

Limit ! !

Bluffton Beaufort

County

HYDROLOGY

Marsh Water

MISCELLANEOUS

TRANSPORTATION

Proposed Parkway

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Paved Road

11⁄2 Existing

School

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Fire Station

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MARCH 26, 2014

Parkway (UC)

0 0.5 1 1.5 2

MAY RIVER

BLUFFTON

BLUFFTON

BEAUFORT

COUNTY

Figure 1—Bluffton region and May River location.
166 Headwaters to Estuaries: Advances in Watershed Science and Management

Assessments for Watershed Management

PROGRAM DESIGN AND 

IMPLEMENTATION

Program Design

The Town’s detailed process to develop and initially 

implement the Action Plan has been previously 

documented (Jones and Bullman 2014). By adapting 

the EPA (2008) guidelines, the Town and its partners 

worked through each of the following steps. While listed 

chronologically, many steps occurred simultaneously and 

are on-going:

Conducted a Social Inventory – identified the 

stakeholders and built partnerships.

Conducted an Environmental Inventory – coalesced 

existing data to determine past and present conditions 

and identify where there were gaps in the data so that 

they could be acquired.

Set Goal and Initial Objectives – the project team and 

decision makers (Town Council) determined what 

“success” would look like and reached consensus to 

identify the goal.

Designed and Created the Watershed Action Plan – as 

the plan was under development, short-, mid-, and 

long-term outcomes which supported the goal were 

developed.

Implemented the Watershed Action Plan – initial 

activities and outputs were implemented to show 

progress and build excitement and momentum toward 

the desired long-term outcomes.

Measure Progress and Make Adjustments – this is 

the initial evaluation of the Action Plan utilizing the 

adaptive management plan logic model strategy to 

determine program effectiveness and is described in 

greater detail below.

Program Implementation

To date under the Action Plan program, nineteen projects 

have produced or are producing on-going outputs for 

evaluation (Table 1). These diverse projects have vastly 

differing approaches as a possible means to improve water 

quality, and include a $480,000 Capital Improvement 

Program (CIP) project, nonstructural BMPs such as public 

outreach and engagement via meetings, events and social 

media, policies in the form of ordinance changes, as 

well as small-scale BMPs intended for individual home 

sites such as rain barrels, rain gardens and bird roosting 

deterrent systems for docks. Thus, evaluating the projects 

over time for efficiencies and effectiveness in attaining the 

Action Plan’s goal to improve water quality and protect 

it into the future will allow Town management to decide 

which projects warrant receiving continued, but limited 

resources (both financial and staff time) and which ones 

should be modified or discontinued.

PROGRAM EVALUATION METHODS

The Town conducted an initial evaluation of the Action 

Plan utilizing the adaptive management logic model 

(Fig. 3) strategy. The ultimate criterion utilized to gauge 

success of the Action Plan is a decrease in fecal coliform 

concentration numbers at SCDHEC shellfish monitoring 

stations, resulting in a re-opening of the closed shellfish 

Figure 2—Iterative process of adaptive management.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 167

Assessments for Watershed Management

ACTION PLAN

 CURRENT INITIATIVES OUTPUTS OUTCOMES MEETING GOAL CONT.?

2011 - 2014 YES NO

1 Fecal Coliform “Hot Spot” 

Monitoring

~1,000 samples collected 

annually

Provides data to assess project effi cacy and evironmental 

indicator for program successes; Provides input for future 

project retrofi t areas.

x YES

2 May River Watershed Action 

Plan Advisory Committee 

Committee formed and meets 

quarterly to review project 

progress and performance 

measures.

Provides public forum to gather input into project, programs & 

initiatives; Provides process for quarterly assessment of data 

and adaptive management of Action Plan.

x YES

3 Neighbors for Clean Water - 

Facebook, Twitter, Website

Brand created; Social media 

sites launched and continued; 3 

watershed entry signs installed.

Continued opportunities to reach a broad audience via social 

media and traditional media venues. x YES

4 Community Clean-Ups Annually - 2 events; with 250 

volunteers; 2 tons collected total 

Community clean-ups will continue and staff will increase 

participation levels by broadening the scope of the events to 

be more festival-like.

x YES

5 Outreach/Education Events & 

Participant #s

Annually 40 events; reach of 

2,000

Continued outreach & engagement is necessary for 

success, however improved performance metrics need to be 

investigated and adopted.

x YES

6

Unifi ed Development Ordinance 

Based on Watershed PrinciplesGrowth Framework Map 

Map directs future growth 

to desired areas to protect 

headwaters.

Uncertain what impact the Growth Framework Map has had 

on development patterns on the whole. ? ? ?

7

Unifi ed Development Ordinance 

Based on Watershed PrinciplesLow Impact Development 

Incentives 

Incentives are identifi ed and 

available.

Uncertain what impact the incentives have had on 

development designs; requires better promotion of availability 

and tracking in the development process.

? ? ?

8

Unifi ed Development Ordinance 

Based on Watershed PrinciplesStormwater Volume Control 

Requires post-construction 

stormwater run-off volumes to 

equal pre-construction levels.

Uncertain what impact the volume requirment has had for 

protecting receiving waterbodies; requires calculation of 

percentage of stormwater volume decrease compared to 

previous design requirements.

? ? ?

9

Unifi ed Development Ordinance 

Based on Watershed PrinciplesTransfer of Development Rights 

1,300 units transferred; prevents 

146 acres impervious surface in 

headwaters.

While this program was effective in this single case, it needs 

to be more broadly promoted and applied. ? ? ?

10 Rain Barrel (55-gallon) 175 installed

Increased awareness and engagement for 150 homeowners 

(several sites received multiple barrels); prevented additional 

run-off from home sites.

x YES

11 Rain Garden (~70 sq. ft. each) 13 installed

Not the most effective stormwater BMP due to cost & 

maintenance needs making homeowners reluctant to 

participate.

x NO

12 Doggie Dooley Pet Septic 

Installation

5 installed in support of “scoop 

the poop” pledge campaign; 30 

pledges signed

While this small-scale program was used as an incentive to 

have pet owners sign a “scoop the poop” pledge to be eligible 

to win a Doggie Dooley, only 30 pledges were made.

x NO

13 Manure Management Plan & 

Riparian Buffer Garden 250 sq. ft. garden installed

This particular project stabilized the soil and provided fi ltration 

of runoff. Wide-spread application of this BMP would be time 

consuming and costly.

? ? ?

14 Bird Roosting Deterrent for 

Docks

40 deterrents obtained; 10 

installed

Homeowners were reluctant to deploy a roosting deterrent 

due to their appearances. x NO

15 Septic System Maintenance 

Assistance Annually - 56 service requests 

Until sanitary sewer service is extended to most residents, 

this program is necessary for environmental and health/

safety/welfare of the public.

x YES

16 New Riverside BMP Pilot Project

1.25 acre lagoon created to treat 

a 300 acre sub-basin; one year 

of monitoring data shows 70% 

reduction in fecal coliform conc.

The long-term effi cacy of a pond to reduce fecal coliform 

loading from an undeveloped drainage area is currently being 

investigated via the monitoring data.

? ? ?

17 Animal Waste Ordinance 

Completed

Adopted; 1 ticket written and 

dismissed by judge

Widespread education in support of this ordinance needs to 

be conducted for police offi cers, judges and general public 

to increase its effectiveness as a BMP for fecal coliform 

reduction.

x YES

18 Trash Can Installation in Old 

Town 6 cans installed

Trash cans are emptied weekly and more frequently after 

festivals, thus preventing debris from entering the river. 

Quantifi cation of amounts needed to determine impact.

x YES

19 Construction Site Sediment & 

Erosion Control Inspections Annually - 1,050 inspections

Sediment and erosion control inspections are effective 

to prevent sediment transport of pollutants to receiving 

waterbodies.

x YES

Table 1—May River Watershed Action Plan outputs, outcomes and evaluation
168 Headwaters to Estuaries: Advances in Watershed Science and Management

Assessments for Watershed Management

harvesting beds, thus attaining the goal of the Action 

Plan. This long-term outcome is an indication of holistic 

watershed health. However, the success of each individual 

project and its outputs which contribute to that goal were 

assessed to determine if short-, and mid-term outcome 

performance measures, previously identified during each 

project’s design, are being achieved.

Town staff, with the input of the six public members 

of the May River Watershed Action Plan Advisory 

Committee (WAPAC), review the status of project 

completion and overall program implementation on a 

quarterly basis. Together, the WAPAC and staff decide 

when evaluation of a project should be conducted at 

meaningful time intervals. If the intended performance 

measures are not being met, further investigation will 

occur as to why. 

Based upon the information, the Action Plan projects, 

performance measures or resources will be adjusted 

as necessary with the input of the WAPAC and other 

stakeholders previously identified during the Action Plan 

planning process. This iterative process will continue until 

the shellfish beds are re-classified as open for harvesting. 

From that point, the Action Plan will continue to be 

assessed using the adaptive management logic model 

approach to ensure future protection of the May River and 

its watershed.

RESULTS

The results of the adaptive management logic model 

evaluation for the Action Plan projects from the last three 

(3) years are presented in Tables 1 and 2. Programs and 

projects that were part of the Town’s first EPA Clean 

Water Act Section 319 Grant, as awarded by SCDHEC, 

are fully summarized in the final report to SCDHEC 

(Jones 2014). 

Evaluating the nineteen Action Plan projects indicates 

that, to date, nine projects resulted in outcomes 

considered to be positive improvements for water quality. 

The outcomes of four projects are not considered to 

be meeting the goal of improving water quality, and 

six projects require modification and re-assessment to 

determine if their outcomes are contributing to water 

quality improvement. 

Sixteen projects are considered worth continuing, though 

seven of those require modifications either in design 

or performance metrics to be fully re-evaluated as they 

are currently not meeting or are uncertain of meeting 

the desired outcomes. Three initiatives – rain gardens, 

Doogie Dooley pet septic installation, and bird roosting 

deterrents – were not considered worth continuation due 

to poor public response or participation, as well as limited 

water quality improvements in spite of high staff effort or 

monetary requirements. 

Figure 3—EPA example of an adaptive management logic model for a watershed 

management plan assessment.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 169

Assessments for Watershed Management

Of the seven projects determined to require modification, 

only one is a structural BMP, while the remaining six 

are policies. The recently completed CIP stormwater 

BMP, the New Riverside Pilot Project Pond, has a year 

of monitoring data collected. Initial indications are that 

the pond is reducing fecal coliform concentrations by 

80 percent. Despite this, the long-term outcome of this 

project is unclear as not enough data have been collected 

yet to fully understand the system.

The six policy-related projects are either not meeting, as 

is the case with the Pet Waste Ordinance, or are unclear 

as to their contribution to the long-term desired outcomes 

and goal of the Action Plan. The metrics of these projects 

must be reassessed, as well as the overall project design, 

to better quantify their contribution to the desired 

outcomes.

DISCUSSION 

The benefits of the adaptive management strategy and 

several case studies are summarized by the EPA (2013) 

in its “A Quick Guide to Developing Watershed Plans 

to Restore and Protect Our Waters.” The routine and 

intensive evaluation and analyses of pre-determined 

performance measure data are crucial to the success of 

any watershed management plan as these ensure the 

plan is current with industry standards and technical 

knowledge as well as adapting to a variable physical 

environment. Additionally, these periodic “check-ups” 

of a plan ensure that tangible steps toward water quality 

improvements are being made to meet not only local 

expectations, but possibly regulatory requirements as 

well if the waterbody in question is subject to a Total 

Maximum Daily Load (TMDL).

The benefits of utilizing the adaptive management logic 

model to assess the Action Plan are evident in the results. 

The evaluation of the projects in the Action Plan indicates 

that approximately half of the initiatives are resulting 

in outcomes considered positive for water quality 

improvement. What is striking is that 38 percent (7 of the 

19 projects) are believed to be producing positive results, 

but require modification of design, performance measures 

or data acquisition to re-evaluate and fully support this 

assumption. Notably, the projects which are unclear 

as to their success are all policies, with the exception 

of the stormwater BMP which, as previously stated, 

requires more time and data to allow a full evaluation. 

This observation points out the need for the Town, and 

others who may adopt a policy as a BMP, to clearly define 

performance measures which can be obtained following 

policy implementation. Additionally, all of the initiatives 

require a quantitative assessment of contributions to fecal 

coliform load reduction. 

Applying the adaptive management approach also 

provided insight to the Town into which efforts are worth 

continuing. Sixteen percent (3 of the 19 projects) are not 

currently considered worthy for continuation based upon 

poor return on staff investment of time and resources, thus 

allowing those resources to be dedicated toward the other 

projects which require modification. Alternatively, if more 

resources (staff and funding) become available, these 

projects may be revised based on the input received to 

improve their reception and implementation by the public.

While applying the adaptive management strategy logic 

model may seem complex, it actually helps to clarify a 

watershed management program’s or individual project’s 

path forward by elucidating where efforts are paying 

off, where they are not, and where it’s unclear. In the era 

of doing “more with less,” while still expected to make 

progress by citizens and regulators, this strategy helps 

to justify managerial decisions aimed at maximizing the 

return on resources expended toward a common goal. 

ACKNOWLEDGMENTS

Numerous individuals and organizations contributed 

to this process. However, no action would have been 

possible without the support of our current and past 

Town Council members including Mayor Lisa Sulka and 

Mayor Pro Tempore Ted Huffman, Karen Lavery, Fred 

Hamilton, Larry Toomer, Oliver Brown, Allyne Mitchell, 

and Charlie Wetmore. Numerous technical partners have 

included USEPA, NOAA-Office for Coastal Management, 

NOAA-CSC Human Dimensions Program, NOAANCCOS, USGS, SCDNR, SCDHEC nonpoint source 

program, SCDHEC-Shellfish Program, SCDHEC-OCRM, 

Clemson University, University of South Carolina, 

University of South Carolina-Beaufort, the Lowcountry 

Institute and the managers of the Beaufort County 

Stormwater Utility. Community partners have included 

 # of Projects 

# of Projects to 

Continue

# of Projects to 

Modify 

# of Projects to 

Discontinue

Meeting Outcomes 9 9 0 0

Not Meeting Outcomes 4 0 1 3

Uncertain of Meeting Outcomes 6 0 6 0

Totals 19 9 7 3

Table 2—Results of the May River Watershed Action Plan evaluation
170 Headwaters to Estuaries: Advances in Watershed Science and Management

Assessments for Watershed Management

members of the May River Waterbody Management Plan 

Implementation Committee and May River Watershed 

Action Plan Advisory Committee. I would like to thank 

the following Town staff for their continued support 

of and contributions to implementing the May River 

Watershed Action Plan – current and past Town Managers 

Marc Orlando and Anthony Barrett, respectively; and the 

dedicated and talented staff especially Jeremy Ritchie, 

Carl Norris, Alex Leinbach, Bill Baugher, Beth Lewis, 

Sam Connor, Ron Bullman, James Ayers, Frank Hodge 

and Shawn Leininger; as well as the Bluffton community.

LITERATURE CITED

AMEC, Center for Watershed Protection, Thomas & Hutton, 

and Ward Edwards, 2011. May River Watershed Action Plan. 

Final Report. Prepared for the Town of Bluffton. 126 pp.

Jones, K.W., 2014. Project # 4B FY 2208, Fecal Load Reduction 

in the May River Watershed. §319 Project Closeout Report. 

Prepared for SCDHEC. 176 p.

Jones, K.W.; Bullman, R. 2014. A Case Study in WatershedBased Plan Development and Implementation for the May 

River Watershed in Bluffton, South Carolina. Journal of 

South Carolina Water Resources. 1:19-25.

South Carolina Department of Health and Environmental 

Control (SCDHEC), 2012. R.61-69, Classified Waters. South 

Carolina Department of Health and Environmental Control, 

Columbia, S.C. 37 p.

SCDHEC, 2014. State of South Carolina Integrated Report for 

2014 Part I: Section 303(d) List of Impaired Waters. South 

Carolina Department of Health and Environmental Control, 

Columbia, S.C. 91 p.

U.S. Census Bureau, 2000. Census of Population, Public Law 

94-171 Redistricting Data File. Updated every 10 years. 

http://factfinder2.census.gov.

U.S. Census Bureau, 2010. Census of Population, Public Law 

94-171 Redistricting Data File. Updated every 10 years. 

http://factfinder2.census.gov.

U.S. EPA, 2008. Handbook for Developing Watershed Plans to 

Restore and Protect Our Waters, EPA 841-B-08-002. 400 p.

U.S. EPA, 2013. A Quick Guide to Developing Watershed Plans 

to Restore and Protect Our Waters, EPA 841-R-13-003. 39 p.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 171

Assessments for Watershed Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE 2014 ASSESSMENT OF STREAM QUALITY IN THE 

PIEDMONT AND SOUTHERN APPALACHIAN MOUNTAIN REGION 

OF SOUTHEASTERN UNITED STATES

Celeste Journey, Paul M. Bradley, Peter Van Metre1

During the spring and summer of 2014, the U.S. Geological Survey (USGS) National WaterQuality Assessment Program (NAWQA) assessed stream quality across the Piedmont and 

southern Appalachian Mountain region in the southeastern United States. The goal of the 

Southeast Stream Quality Assessment (SESQA) is to characterize multiple water-quality 

factors that are stressors to aquatic life – contaminants, nutrients, sediment, and streamflow 

alteration – and the relation of these stressors to ecological conditions in streams throughout 

the region. Two of the most important anthropogenic factors affecting water quality in the 

region are urbanization and streamflow alteration; therefor, these factors were targeted in the 

assessment. Findings from the assessment will provide communities and policymakers with 

information about what human and environmental factors are the most critical in controlling 

stream quality, which will provide insight about possible approaches to protect and improve 

stream quality. The targeted design of the assessment used streamflow and land-use data to 

identify and select sites that reflected a range in the amount of urbanization and streamflow 

alteration. One hundred twenty-one sites were selected and sampled across the region for 

as many as 10 weeks during April, May, and June 2014 for contaminants, nutrients, and 

sediment. This water-quality “index” period culminated with an ecological survey of habitat, 

periphyton, benthic macroinvertebrates, and fish at all sites. Sediment was collected during 

the ecological survey for analysis of sediment chemistry and toxicity testing. Of the 121 sites, 

59 were on streams in watersheds with varying degrees of urban land use, 5 were on streams 

with numerous confined feeding operations (CAFOs), and 13 were reference sites with little 

or no development in their watersheds. The remaining 44 “hydro” sites were on streams 

in watersheds with relatively little agricultural or urban development but with hydrologic 

alteration, such as a dam or reservoir. This presentation will provide a detailed description 

of and preliminary findings from the specific study components of the SESQA that included 

surveys of ecological conditions, routine water sampling, deployment of passive polar organic 

compound integrative samplers (POCIS) of pesticides and contaminants of emerging concern, 

and synoptic sediment sampling and toxicity testing at all urban, CAFO, and reference sites. 

At a subset of urban sites, continuous water-quality monitoring and daily pesticide sampling 

also were conducted and will be described. Hydro sites had a reduced scope for its assessment 

that included synoptic surveys of ecology, sediment chemistry, and water chemistry.

1

Celeste Journey, South Carolina Water-Quality Specialist, US Geological Survey, Columbia, SC 29210

Paul Bradley, Research Scientist, US Geological Survey, Columbia, SC 29210

Peter Van Metre, Hydrologist, US Geological Survey, Austin, TX 78754
172 Headwaters to Estuaries: Advances in Watershed Science and Management

Assessments for Watershed Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

CEAP WATERSHED ASSESSMENTS: ACCOMPLISHMENTS 

AND OPPORTUNITIES FOR NEW ADVANCES

Lisa Duriancik, Mark Walbridge, Deanna Osmond, Roberta Parry1

The Conservation Effects Assessment Project (CEAP) was established in 2003 to document 

the effects and benefits of conservation practices. CEAP conducts assessments at multiple 

scales – national, regional, and watershed scale – on croplands, grazing lands and wetlands, 

and to address wildlife concerns. A major part of CEAP since its inception included 

a collection of 42 small Watershed Assessment Studies, involving 3 USDA agencies 

along with numerous other Federal and university partners. These long term studies have 

documented cases of water quality improvements at the watershed and other scales in some 

circumstances and all have been key in identifying existing challenges to measuring the 

water resource outcomes of conservation implementation at the scale of a watershed. Recent 

accomplishments will be reviewed. Future opportunities will be discussed including continued 

assessment of conservation effects within watersheds, particularly in conjunction with targeted 

conservation implementation. Looming water and soil resource challenges and conditions will 

be considered and to better inform conservation treatment needs.

1

Lisa Duriancik, CEAP Watersheds Leader, USDA Natural Resources Conservation Service, Beltsville, MD 20705

Mark Walbridge, Water Availability and Watershed Management National Program Leader, USDA Agricultural Research Service, Beltsville, 

MD 20705

Deanna Osmond, Professor, Department of Soil Science, North Carolina State University, Raleigh, NC 27695

Roberta Parry, Agriculture Policy Specialist, US Environmental Protection Agency, Washington, DC 20460
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 173

Assessments for Watershed Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

USDA’S NATIONAL INSTITUTE OF FOOD AND AGRICULTURE (NIFA): 

ENGAGING KNOWLEDGE AND TECHNOLOGY, INCENTIVES AND 

POLICIES TO PROMOTE APPROPRIATE DECISION MAKING IN THE 

MANAGEMENT OF WATER AND WATERSHEDS

James Dobrowolski1

Agriculture, across the value chain, is the greatest consumptive user of water resources in 

the United States and around the world. Perhaps the greatest challenge facing agricultural 

producers will be increased agricultural production to meet rising demand in the face of 

limited water resources. This will require producers to adapt water management strategies 

to an increasingly variable climate, extreme weather conditions, and frequent occurrence of 

droughts. The development of new science and technologies focused on widening the array 

of choices for the efficient use of water, sustaining water quality and managing watersheds 

at multiple scales and for multiple purposes is needed. USDA National Institute of Food and 

Agriculture’s (NIFA) water and watersheds science, education and extension/outreach (REE) 

portfolio engages knowledge and technology, incentives, and policies to promote appropriate 

decision making. Water and watersheds address critical water resources issues such as 

drought, excess soil moisture, flooding, availability (quality + quantity) in an agricultural 

context. Ongoing drought conditions in the western and southwestern U.S. as well as drought 

and excess moisture conditions in the southern and eastern U.S. make continued activity and 

support for water and watersheds REE a critical focus of NIFA’s funding portfolio. Significant 

variations from the historical rate of water supply, demand and quality are projected to have 

major impacts on rural, urbanizing and peri-urban agricultural, horticultural, forest, and 

rangeland production systems. NIFA’s water and watersheds program focuses on developing 

solutions for water management that form a nexus across food, water, climate, energy, 

human health and the environment. Funding will continue to be used to develop technologies 

and tools for a broad group of stakeholders to sustain and improve water availability. We 

propose to present NIFA’s systems approach to public funding that links social, economic 

and behavioral sciences with biophysical sciences and engineering to address water and 

watershed issues.

1

Watershed Scientist and National Program Leader for Water and Rangeland and Grassland Ecosystems Programs, USDA National Institute of Food 

and Agriculture, Washington, DC 20024

Water Quality 

(PART 2)
176 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Quality (Part 2)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

SOIL AND STREAM CHEMISTRY RELATIONSHIPS IN 

HIGH ELEVATION WATERS

Jennifer Knoepp, Katherine J. Elliott, William A. Jackson, James M. Vose, 

Chelcy Ford Miniat, Stanley J. Zarnoch1

High elevation watersheds in the southern Appalachian Mountains have unique soils and 

vegetation communities. They also receive greater inputs of acidic deposition as a result of 

increased precipitation compared to lower elevation sites. Since the implementation of the 

Clean Air Act Amendment in 1990, concentrations of acidic anions in rainfall have been 

declining; however, some high elevation watersheds continue to show signs of chronic 

or episodic acidity. In three large watersheds, North River in Cherokee National Forest, 

Santeetlah Creek in Nantahala National Forest, and North Fork of the French Broad in 

Pisgah National Forest, we selected five catchments within each to represent the range in 

elevation. We collected stream and organic and mineral soil samples seasonally, and measured 

soil chemistry, mineral soil lime requirement, overstory composition and qualitative site 

characteristics in each catchment. Watersheds differed in stream acid neutralizing capacity 

(ANC) and soil chemistry; catchments within watersheds differed in overstory vegetation 

composition. We used a mixed model statistical approach to determine soil chemical, 

vegetation, and site characteristic variables that best explained variation in stream ANC. 

Stream ANC values averaged 42 μeq L-1 for North River, 24 μeq L-1 for Santeetlah Creek 

and 19 μeq L-1 for North Fork; and ANC was related to soil exchangeable and total cation 

concentrations and vegetation characteristics such as overstory species composition and total 

basal area. Our analyses suggest that vegetation characteristics as well as organic and mineral 

soil cation and total carbon concentrations are indicators of stream ANC and thus, may be 

useful in identifying sites for which lime application could be used to restore streams from the 

impacts of acid deposition.

1

Jennifer Knoepp, Research Soil Scientist, USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, NC 28763

Katherine J. Elliott, Research Ecologist, USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, NC 28763

William A. Jackson, Air Resource Specialist, USDA Forest Service, National Forests of North Carolina, Asheville, NC 28801

James M. Vose, Project Leader, USDA Forest Service, Southern Research Station, Center for Integrated Forest Science, Raleigh, NC 27709

Chelcy Ford Miniat, Research Project Leader, USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, NC 28763

Stanley J. Zarnoch, Mathematical Statistician, USDA Forest Service, Southern Research Station, Clemson, SC 29634
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 177

Water Quality (Part 2)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

SOIL AND SALINITY MOBILIZATION AND TRANSPORT 

IN THE COLORADO RIVER BASIN

Cole Green Rossi, Mark A. Weltz, Kossi Nouwakpo, Ken McGwire1

Federally, the evaluated potential of soil loss risk in national reports in the past and ways to 

adapt to be proactive in preventing accelerated soil loss on rangelands has been incomplete. 

The areas where it is difficult to measure due to the complexities of multiple interactions 

(splash, sheet and rill formation, landscape dominated by wind and water processes, presence 

of iron oxide nodes, etc.) is only a small fraction. Rangeland soils are generally consolidated, 

uncultivated, and have lower organic matter content than cropland soils. These soils can have 

various slopes and debris such as rock, gravel, plant litter, woody debris and biological soil 

crusts. The vegetation is irregular and patchy with varied heights and varieties. Our approach 

takes all of this into consideration by triplicating rainfall simulations at four rates on natural 

soils (hoofprints). The rainfall simulator conducts 2, 10, 25, and 50-year return period rainfall 

events on 10 different plots in triplicate. Runoff water was collected to measure salinity 

and sediment that could eventually reach the Colorado River. Rainfall intensity and the log 

of sampling time were the two most sensitive variables when modeling the data. A rainfall 

simulator with cameras and sensors run by a computer versus LIDAR were used per plot 

to eventually compare photographic evidence and expense to determine if this new method 

is a more cost effective and wiser choice to use on rangelands. Ultimately, the Rangeland 

Hydrologic Ecosystem Model (RHEM), which has now been integrated into APEX will 

capture the vegetation and small measures of what is being captured within the 6 m x 2 m 

plot, the model will be adjusted for salts and for effervescence (once the soil is dry, the salt 

resurfaces and attaches itself to plant roots). This also extends the plant.dat database in APEX 

and RHEM related parameters. We have been successful at two sites in Utah and are arranging 

for additional sites in Utah as well as Colorado, New Mexico and other areas residing within 

the Colorado River Basin initially due to the geology and the focus on the Colorado River. 

Having all of the data will take a minimum of three additional years to be able to compare 

sites and run model simulations and compare LIDAR results to the unique rainfall simulator 

camera and sensor data for surface runoff, sediment, and salinity.

1

Cole Green Rossi, Water Quality Salinity Specialist, USDOI Bureau of Land Management, Salt Lake City, UT 84101

Mark Weltz, Rangeland Scientist, USDA Agricultural Research Service, Reno, NV 89512

Kossi Nouwakpo, Research Soil Scientist, University of Nevada, Reno, NV 89557

Ken McGwire, Associate Research Professor, Desert Research Institute, Reno, NV 89512
178 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Quality (Part 2)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

NUTRIENT AND SALT MASS BALANCE ON THE LOWER ARKANSAS 

RIVER AND A CONTRIBUTING TRIBUTARY IN AN IRRIGATED 

AGRICULTURAL SETTING

Alexander Huizenga, Ryan T. Bailey, Timothy K. Gates1

The Lower Arkansas River Basin is an irrigated, agricultural valley suffering from high 

concentrations of nutrients and salts in the coupled groundwater-surface water system. The 

majority of water quality data collection and associated spatial analysis of concentrations 

and mass loadings from the aquifer to the stream network has been performed at the regional 

scale (> 500 km2). This study attempts to monitor and quantify hydro-chemical processes 

on a small spatial and temporal scale in specific locations in the region. Using a suite of instream instruments and observation piezometers along the stream corridor, a 4.7 km reach 

of the Arkansas River, as well as a 2 km reach of a contributing tributary, Timpas Creek, 

were monitored in order to quatify mass inputs and outputs of nutrients (N, P). Monitoring 

included growing season length water quality sampling, as well as two high-intensity 

monitoring events. Using this monitoring data, a mass-balance approach was used to quantify 

groundwater-surface interactions and exchanges for nitrate loadings in the Arkansas River. 

Results suggest that significant in-stream processing of nitrate occurs in the Arkansas River 

during low discharges and that nitrate degredation through denitrification and vegetative 

uptake occurs in the riparian zones of the river and creek. The information and data gathered 

from this research will clarify the needs for future data gathering efforts in the region and 

provide a database from which to draw for future small-scale groundwater-surface water 

modelling efforts in the Lower Arkansas River Valley.

1

Alexander Huizenga, Graduate Student, Civil and Environmental Engineering Department, Colorado State University, Fort Collins, CO 80523 

Ryan Bailey, Assistant Professor, Civil and Environmental Engineering Department, Colorado State University, Fort Collins, CO 80523 

Timothy Gates, Professor, Civil and Environmental Engineering Department, Colorado State University, Fort Collins, CO 80523
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 179

Water Quality (Part 2)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

EVALUATING THE EFFECTS OF WOODY BIOMASS PRODUCTION 

FOR BIOENERGY ON WATER QUALITY AND HYDROLOGY IN THE 

SOUTHEASTERN UNITED STATES

Natalie Griffiths, C. Rhett Jackson, Menberu Bitew, Enhao Du, Kellie Vaché, 

Jeffrey J. McDonnell, Julian Klaus, and Benjamin M. Rau1

Forestry is a dominant industry in the southeastern United States, and there is interest in 

sustainably growing woody feedstocks for bioenergy in this region. Our project is evaluating the 

environmental sustainability (water quality, quantity) of growing and managing short-rotation 

(10-12 yrs) loblolly pine for bioenergy using watershed-scale experimental and modeling 

approaches. The 3 study watersheds (R: 45 ha; B: 169 ha; C: 117 ha) are located in the Upper 

Coastal Plain of South Carolina, with characteristics typical of the landscape including low-relief 

topography and low- to moderate-quality sandy soils overlaying a clayey argillic horizon. In 

2010, the watersheds were instrumented and hydrologic and water quality (nitrogen, phosphorus, 

dissolved organic carbon, herbicides) measurements began in streams, riparian and deep 

groundwater, interflow, precipitation, and throughfall. After 2 years of baseline monitoring (2010-

2012), approximately 40 percent of the 2 treatment watersheds (B, C) were harvested (2012) 

and planted with loblolly pine seedlings (spring 2013) with the third watershed (R) serving as 

an unmanipulated reference. Fertilizers and herbicides were applied yearly following planting 

to achieve high yields. All silvicultural activities followed South Carolina Best Management 

Practices (BMPs), and thus our project will also evaluate whether typical BMPs are adequate to 

protect water resources under short-rotation woody crop production for bioenergy feedstocks.

Overland flow has not been observed in these low-relief watersheds, and while seeps appear 

during wet climate periods in newly planted areas, water reinfiltrates within the first few meters 

of the riparian zone. Interflow (water flowing through soils) occurs on and within the clay layer 

following precipitation events, but a combination of shallow topography and anomalies in the 

clay result in short interflow distances (tens of meters). Therefore, the hillslopes where pine 

is planted are largely hydrologically disconnected from the streams, except in steeper-sloped 

areas near the riparian zone. A combination of runoff ratios, temporal groundwater elevation 

profiles, and water and nitrate stable isotopes suggest that groundwater is the dominant flowpath 

in these watersheds. Thus excess fertilizers or herbicides will likely first enter groundwater and 

then stream water following a several year lag. The post-treatment water quality data support 

this hypothesis. There have been no appreciable increases in stream water ammonium, nitrate, 

or soluble reactive phosphorus concentrations in the treatment watersheds (B, C) compared to 

the control (R) watershed. However, the post-treatment groundwater nitrate concentrations are 

increasing (<2 mg N/L in 2014). Measurements are planned to occur until canopy closure (2018).

1

Natalie Griffiths, Staff Scientist, Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, 

Oak Ridge, TN 37831

C. Rhett Jackson, Professor, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602

Menberu Bitew, Post-Doctoral Research Scientist, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602

Enhao Dua, Warnell School of Forestry and Natural Resources, University of Georgia; currently a Postdoctoral Fellow, Lawrence Berkeley National 

Laboratory, Berkeley, CA 94720

Kellie Vaché, Assistant Professor, Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97331

Jeffrey J. McDonnell, Professor, School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, Canada S7N 3H5

Julian Klaus, School of Environment and Sustainability, University of Saskatchewan; currently a Senior Scientist, Department of Environment and 

Agro-Biotechnologies, Centre de Recherche Public Gabriel Lippmann, Belvaux, Luxembourg

Benjamin M. Rau, Research Ecologist, USDA Forest Service, Savannah River Forestry Sciences Lab, Aiken, SC 29803
180 Headwaters to Estuaries: Advances in Watershed Science and Management

Water Quality (Part 2)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

UNDERWATER AERATION AND ARTIFICIAL FLOATING WETLANDS 

TO TREAT WATER QUALITY NUTRIENT ISSUES IN PONDS

Mike Haberland, Craig McGee1 

Hopkins Pond, New Jersey, experiences cyanobacteria blooms due to thermal stratification, 

and eutrophication caused by excessive phosphorous levels. In 2013, a diffused aeration 

system was installed in the pond designed to maximize water lift rate and transfer rate 

of dissolved oxygen by the release of extremely fine air bubbles along the pond bottom. 

The rising bubbles draw bottom water along with them to the surface creating an artificial 

circulation. This circulation mixes water that otherwise would thermally stratify, and increases 

the dissolved oxygen content throughout the water column. Oxygenating deeper waters near 

the pond bottom also results in a decrease in the release of phosphorous from the sediment. 

In addition to the aeration system, as a demonstration project, we designed and installed 

350 square feet of artificial floating wetlands (AFWs) using a biological filter substrate and 

wetland plants for nutrient removal. AFWs reduce nitrogen and phosphorous in a water body 

using natural microbial action in the filter substrate and uptake by obligate aquatic vegetation. 

Microbiological activity plays a major role in nutrient removal in wetland systems and the 

large surface area of the woven floating wetland material provides a tremendous amount of 

substrate for the growth of bacteria. The AFWs are anchored offshore in water depths that 

exceed the normal habitat requirements for the plant material and yet are able to continue to 

provide the same water treatment ecosystem services as their land based counterparts. Since 

installation of these treatment devices phosphorous levels dropped from 0.126 mg/L down 

to 0.08 mg/L.

1

Mike Haberland, Environmental Agent for Rutgers Cooperative Extension, Rutgers University, Cherry Hill, NJ 08002

Craig McGee, District Manager, Camden County Soil Conservation District, West Berlin, NJ 08091
Monitoring and Management
182 Headwaters to Estuaries: Advances in Watershed Science and Management

Monitoring and Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

REGIONAL EFFECTS OF AGRICULTURAL CONSERVATION 

PRACTICES ON NUTRIENT TRANSPORT

Anna Maria Garcia, Richard B. Alexander, Jeffrey G. Arnold, Lee Norfleet, 

Mike White, Dale M. Robertson, Gregory Schwarz1

The Conservation Effects Assessment Program (CEAP), initiated by USDA Natural 

Resources Conservation Service (NRCS), has the goal of quantifying the environmental 

benefits of agricultural conservation practices. As part of this effort, detailed farmer surveys 

were compiled to document the adoption of conservation practices. Survey data showed 

that up to 38 percent of cropland in the Upper Mississippi River basin is managed to reduce 

sediment, nutrient and pesticide loads from agricultural activities. The broader effects of 

these practices on downstream water quality are challenging to quantify. The USDA-NRCS 

recently reported results of a study that combined farmer surveys with process-based models 

to deduce the effect of conservation practices on sediment and chemical loads in farm runoff 

and downstream waters. As a follow-up collaboration, USGS and USDA scientists conducted 

a semi-empirical assessment of the same suite of practices using the USGS SPARROW 

(SPAtially Referenced Regression On Watershed attributes) modeling framework. SPARROW 

is a hybrid statistical and mechanistic stream water quality model of annual conditions that 

has been used extensively in studies of nutrient sources and delivery. In this assessment, 

the USDA simulations of the effects of conservation practices on loads in farm runoff were 

used as an explanatory variable (i.e., change in farm loads per unit area) in a component of 

an existing a SPARROW model of the Upper Midwest. The model was then re-calibrated 

and tested to determine whether the USDA estimate of conservation adoption intensity 

explained a statistically significant proportion of the spatial variability in stream nutrient 

loads in the Upper Mississippi River basin. The results showed that the suite of conservation 

practices that NRCS has catalogued are a statistically significant feature in the Midwestern 

landscape associated with nitrogen runoff and delivery to downstream waters. Estimates of the 

magnitude of this effect using SPARROW indicated that conservation practices have played 

a significant role in reducing nutrient pollution from agricultural activities to downstream 

receiving water bodies.

1

Anna Maria Garcia Hydrologist, US Geological Survey, Raleigh, NC 27607

Richard Alexander, Research Hydrologist, US Geological Survey, Reston, VA 20192

Jeffrey Arnold, Supervisory Agricultural Engineer, USDA Agricultural Research Service, Grassland Soil and Water Research Laboratory, Temple, TX 76502

Lee Norfleet, Model Team Leader, USDA Natural Resources and Conservation Service, Temple, TX 76502

Mike White, Agricultural Engineer, USDA Agricultural Research Service, Grassland Soil and Water Research Laboratory, Temple, TX 76502

Dale Robertson, Research Hydrologist, US Geological Survey, Wisconsin Water Science Center, Middleton, WI 53562

Gregory Schwarz, Economist, US Geological Survey, Reston, VA 20192
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 183

Monitoring and Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ASSESSMENT OF FORESTRY BEST MANAGEMENT 

PRACTICES, I: STREAM WATER CHEMISTRY NATURAL 

VARIABILITY AND FERTILIZATION INFLUENCES

Erik Schilling, Daniel McLaughlin, Matt Cohen, Larry Korhnak, 

Paul Decker, Camille Flinders1

Nutrient pollution can be a leading cause of impairment to some U.S. waters. As a result, 

state and federal agencies are actively engaged in designing management programs and 

numeric nutrient criteria (NNC) to address nutrient impairments. Following implementation 

of the Clean Water Act, Florida, like other timber producing states, developed, tested and 

implemented best management practices (BMPs) to reduce potential impacts to water 

resources resulting from forest management activities. While decades of research have 

continually documented the effectiveness of forestry BMPs, questions remain about their 

effectiveness, particularly for nutrients. Concerns about nutrient responses to forest activities 

are particularly important in Florida, one of the first states to develop NNC for springs, lakes 

and other flowing waters. Therefore, assessing the effectiveness of forestry nutrient BMPs on 

established NNC endpoints is a crucial exercise. To that end, the Florida Fertilization Study 

is designed to evaluate the response of the State’s forestry BMPs to protect water resources 

and aquatic ecosystems during fertilization operations. In this paired watershed study, 

we employed a novel suite of in situ sensors in coastal blackwater streams to collect high 

resolution data (sub-hourly to sub-daily) on flow, nitrate, soluble reactive phosphorus (SRP), 

colored dissolved organic matter (CDOM), turbidity, dissolved oxygen (DO), pH, and specific 

conductance. Such sensors provide new tools to enumerate seasonal to sub-daily variation 

in water chemistry and flow, improving inferences of controls acting at different scales. Data 

will be used to compare baseline and post-fertilization conditions and to isolate fertilization 

effects from natural variation. First year pre-fertilization data clearly demonstrate large solute 

and flow variation in response to rainfall and day-night cycles. These latter diurnal patterns 

are evident in several analytes (flow, CDOM, DO), suggesting both watershed (transpiration) 

and instream (metabolism) influences. Flow variation has significant water quality effects, 

including enrichment of organic nitrogen and dilution of SRP. These data allow us to quantify 

natural variation in multiple parameters at the temporal scales at which they actually vary, 

and thus provide a much richer and more precise approach to elucidating the effects of forest 

fertilization and BMP effectiveness.

1

Erik Schilling, Senior Research Scientist, National Council for Air and Stream Improvement, Aubrey, TX 76227

Daniel McLaughlin, Assistant Professor, Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA 24061

Matt Cohen, Assistant Professor, School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32611

Larry Korhnak, Research Technician, School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32611

Paul Decker, Graduate Student, School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32611

Camille Flinders, Aquatic Biology Program Manager, National Council for Air and Stream Improvement, Anacortes, WA 98221
184 Headwaters to Estuaries: Advances in Watershed Science and Management

Monitoring and Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ASSESSMENT OF FORESTRY BEST MANAGEMENT 

PRACTICES, II: PATTERNS IN STREAM BIOLOGICAL ENDPOINTS IN 

TERMS OF NATURAL VARIABILITY AND FERTILIZATION

Camille Flinders, Daniel L McLaughlin, Larry Korhnak, William J Arthurs, 

Joan Ikoma, Matthew J Cohen, Erik B Schilling1

Watersheds dominated by forest cover typically have high quality water. In managed forests, 

fertilizers may be periodically applied during the growing period. The Florida Forest Service 

has developed Best Management Practices (BMPs) for managed forests to minimize the 

potential impacts of forestry operations, including fertilization, to forest streams and maintain 

water quality. However, a comprehensive study evaluating stream condition (i.e. water quality 

and biota) prior to, during, and following fertilization in the context of BMPs and natural 

variability has not been conducted. In 2012 we undertook a 5 year study to characterize 

stream condition prior to, during, and following fertilizer application in two managed forests 

in central Florida. In conjunction with extensive hydrological and water quality monitoring, 

we evaluated physical and biological benchmarks associated with Florida’s Department of 

Environmental Protection (FDEP) numeric nutrient criteria. Three sites on two managed 

forest streams in north Florida were evaluated for phytoplankton chlorophyll a (chl a), aquatic 

vegetation and periphyton biomass (Linear Vegetation and Rapid Periphyton Surveys), 

habitat condition, and benthic invertebrate assemblages (Stream Condition Index, SCI). 

Macroinvertebrate assemblages on Hester-Dendy multiplate samplers were also collected to 

evaluate temporal variability. Samples are collected at least twice per year for some endpoints 

(SCI) and up to 8 times per year for others (artificial substrates). To date and in both streams, 

phytoplankton chl a, aquatic vegetation, and periphyton biomass values are attaining FDEP’s 

nutrient thresholds. Macroinvertebrate SCI scores classified both stream as “healthy” and/or 

“exceptional” in the first year of the study. Macroinvertebrate data from artificial substrates 

showed distinct assemblages for each site even within a stream, with some site-specific 

seasonal variation. Detailed study findings to date will be discussed in the context of forest 

BMPs and temporal variability.

1

Camille Flinders, Aquatic Biology Program Manager, National Council for Air and Stream Improvement, Anacortes, WA 98221

Daniel McLaughlin, Assistant Professor, Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA 24061

Larry Korhnak, Research Technician, School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32611

William Arthurs, Research Associate, National Council for Air and Stream Improvement, Anacortes, WA 98221

Joan Ikoma, Research Associate, National Council for Air and Stream Improvement, Anacortes, WA 98221 

Matthew Cohen, Assistant Professor, School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32611

Erik Schilling, Senior Research Scientist, National Council for Air and Stream Improvement, Aubrey, TX 76227
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 185

Monitoring and Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

CONTINUOUS WATER-QUALITY MONITORING TO 

IMPROVE LAKE MANAGEMENT AT LAKE MATTAMUSKEET 

NATIONAL WILDLIFE REFUGE

Michelle Moorman, Tom Augspurger1

The U.S. Fish and Wildlife Service has partnered with U.S. Geological Survey to establish 

2 continuous water-quality monitoring stations at Lake Mattamuskeet. Stations on the east 

and west side of the lake measure water level, clarity, dissolved oxygen, pH, temperature, 

salinity, and conductivity. The west side is classified as hyper-eutrophic and is dominated by 

cyanobacteria, while the east side is classified as eutrophic and has a declining population of 

submerged vegetation. The lake is an important wintering habitat for migratory waterfowl 

on the Atlantic flyway. Managers are concerned about submerged vegetation declines due to 

poor water quality. Project objectives include collecting continuous-monitoring data, assisting 

with a cooperative assessment of the lake by collecting monthly water-quality samples, 

and providing input on the development of a comprehensive lake monitoring plan. Lake 

Mattamuskeet provides one example of how multiple agencies can work in partnership to 

improve understanding of the lake’s water-quality dynamics.

1

Michelle Moorman, Biologist, US Geological Survey, Raleigh, NC 27607

Tom Augspurger, Ecologist, US Fish and Wildlife Service, Raleigh, NC 27606
186 Headwaters to Estuaries: Advances in Watershed Science and Management

Monitoring and Management

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

MANAGING WATERSHEDS TO CHANGE WATER QUALITY: 

LESSONS LEARNED FROM THE NIFA-CEAP WATERSHED STUDIES

Deanna Osmond, M. Arabi, D. Hoag, G. Jennings, D. Line, A. Luloff, 

M. McFarland, D. Meals, A. Sharpley1

The Conservation Effects Assessment Project (CEAP) is an USDA initiative that involves the 

Agricultural Research Service, the National Institute for Food and Agriculture (NIFA), and the 

Natural Resources Conservation Service. The overall goal of CEAP is to provide scientifically 

credible estimates of the environmental benefits obtained from USDA conservation programs. 

One of the CEAP projects was to determine the effectiveness of water quality change at 

the watershed scale. Funding for these watershed studies were provided by USDA-NIFA 

and -NRCS. The 13 watersheds selected for this protocol had minimally five years of water 

quality and land use data, and a modeling and socioeconomic component. As the 13 NIFACEAP watershed studies were finishing, a team led by NC State University began the task 

of synthesizing lessons learned about managing agricultural landscapes to meet physical, 

biological, and chemical water quality goals. The NC State team reviewed project documents 

and conducted site visits and key informant interviews at all 13 NIFA-CEAP watersheds. 

The objective of the key informant interviews was to ascertain community values relative to 

water quality and conservation practice adoption. By using all sources of information, lessons 

learned were synthesized into general categories – water quality, land treatment, modeling, 

socio-economic, education, and project management. The information was then crystalized 

into the most critical 15 lessons learned and these will be presented and discussed.

1

Deanna Osmond Professor, Department of Soil Science, North Carolina State University, Raleigh, NC 27695

M. Arabi, Associate Professor, Civil and Environmental Engineering, Colorado State University, Fort Collins, CO 80523

D. Hoag, Professor, Agricultural and Resource Economics, Colorado State University; Fort Collins, CO 80523

G. Jennings, Engineer, Jennings Environmental, Apex, NC 27502 

D. Line, Extension Specialist, Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695

A. Luloff, Professor, Agricultural Economics, Sociology, and Education, Penn State, University Park, PA 16802

M. McFarland, Associate Department Head and Extension Program Leader, Department of Soil and Crop Sciences, Texas A&M, College Station, TX 77843

D. Meals, Environmental Consultant, Ice.Nine Environmental Consulting, Burlington, VT 05401

A. Sharpley, Professor, Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AK 72701
Linking Terrestrial and Marine Ecosystems
188 Headwaters to Estuaries: Advances in Watershed Science and Management

Linking Terrestrial and Marine Ecosystems

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE PHYSICAL AND GEOCHEMICAL INTERACTION BETWEEN 

A TIDALLY-DOMINATED ESTUARY SYSTEM (WASSAW SOUND, GA) 

AND A RIVER-DOMINATED ESTUARY (SAVANNAH RIVER, GA) 

THROUGH SALINITY AND INORGANIC CARBON

Mike Scaboo, Christopher Hintz1

The Wilmington, Bull, and Savannah Rivers are interconnected waterways that flow 

through adjacent Savannah and Wassaw Sound Estuaries. These systems are linked by the 

upper reaches of the Wilmington River maintained as part of the Intracoastal Waterway. 

Significant changes to the Savannah River began in December 2014 with the initiation of 

the Savannah Harbor Expansion Project. The purpose of this study was to determine the 

extent of interaction between the Wilmington and Savannah Rivers using a suite of physical 

and chemical parameters. Samples were collected 1 m above the benthos and 1 m below the 

surface. Sampling occurred in the summer 2012-2014 during high and low tides on the same 

days, on spring and neap tides in the same month, extending into the fall in 2014. Drought, 

flood, and average rainfall years were captured. Samples were analyzed for temperature, 

salinity, carbonate chemistry, dissolved oxygen and stable carbon isotope along the river 

transects. DIC ranged from 875 μmol kg-1 to 2250 μmol kg-1 and pH ranged from 7.11 to 7.79. 

The flooding of the Savannah River in 2013 saw salinities in the Wilmington River as low 

as 7 ppt while during the drought and average years salinities between 13 and 17 ppt were 

observed. The only freshwater input for the Wilmington River is from the Savannah River 

and can be detected on the surface through half of the Wilmington River. There is negligible 

detection of Savannah River water in the Bull River. The Bull and Wilmington rivers connect 

through the narrow St. Augustine Creek. Water from the Wilmington River may be blocked 

by a sill formed at the entrance to Bull River. Estuarine pH was lower during low tide in the 

rivers with CO2 input from respiration in the high marsh during high tide. The pH was also 

lower overall between 2012 and 2014, likely due to the difference in a drought and average 

rainfall year. The deepening of the Savannah River will allow more salt water moving up river, 

which may redirect more surface water into the Wilmington River increasing the freshwater 

influence to the ecosystem.

1

Mike Scaboo, Graduate Student, Department of Marine and Environmental Sciences, Savannah State University, Savannah, GA 31404

Christopher Hintz, Assistant Professor, Department of Marine and Environmental Sciences, Savannah State University, Savannah, GA 31404
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 189

Linking Terrestrial and Marine Ecosystems

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATER SOURCES IN MANGROVES IN FOUR 

HYDROGEOMORPHIC SETTINGS IN FLORIDA AND MEXICO

Christina Stringer, Mark Rains1

Mangroves are transitional environments, where fresh water from the terrestrial environments 

mix with seawater from the marine environment. The relative contributions of these sources 

vary and play a role in controlling the physical and chemical hydrological characteristics of 

mangroves and facilitate the exchange of mass, energy, and organisms between mangroves 

and the surrounding hydrological landscape. Therefore, understanding the water sources in 

mangroves is a critical first step in developing sound management strategies. We examined 

the hydrogeochemistry of four mangrove communities in distinct hydrogeomorphic settings 

along the Costalegre on the central Pacific coast of Mexico and along the Indian River 

Lagoon, east-central Florida. Salinities varied, with values ~9 psu in a basin mangrove, ~17 

psu in a riverine mangrove, ~33 psu in a fringe mangrove, and a range of ~30-75 psu in a 

carbonate barrier island mangrove. Salinity, cation and anion concentrations, and isotopic 

signatures were used as tracers in mass-balance mixing models to quantify estimates of 

relative fresh-water and seawater contributions to each mangrove. The basin mangrove had 

mean fresh-water contribution estimates of 63-84 percent; the riverine mangrove had freshwater estimates of 39-51 percent; and the fringe mangrove had fresh-water contributions 

of 0-5 percent. In contrast, waters in the carbonate barrier island mangrove exhibited 

no characteristics indicative of any fresh-water contribution. These results illustrate the 

varying role that groundwater plays in mangrove hydrodynamics, and the potential role that 

hydrogeomorphic classification can play in helping to make first-order estimates to mangroves 

in different hydrogeomorphic settings.

1

Christina Stringer, Research Hydrologist, USDA Forest Service, Cordesville, SC 29434

Mark Rains, Associate Professor, School of Geosciences, University of South Florida, Tampa, FL 33620
190 Headwaters to Estuaries: Advances in Watershed Science and Management

Linking Terrestrial and Marine Ecosystems

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

DESIGNING A MANGROVE RESEARCH AND DEMONSTRATION 

FOREST IN THE RUFIJI DELTA, TANZANIA

Mwita M. Mangora, Mwanahija S. Shalli, Immaculate S. Semesi, 

Marco A. Njana, Emmanuel J. Mwainunu, Jared E. Otieno, 

Elias Ntibasubile, Herry C. Mallya, Kusaga Mukama, Matiko Wambura, 

Nurdin A. Chamuya, Carl C. Trettin, Christina E. Stringer1

Despite the growing body of literature on science and management of mangroves, there 

is a considerable knowledge gap and uncertainty at local levels regarding the carbon 

pool size, variability of carbon sequestration and carbon stocks within mangrove forests, 

mechanisms that control carbon emissions from degradation of mangrove forests, impacts 

of conversion to other land uses, challenges and opportunities associated with restoration 

practices and sustainability of ecosystem services. These concerns are valid globally, but 

they are particularly important in Africa due to limited research that has been conducted 

in the continent. The USDA Forest Service (USFS) and the Center for International Forest 

Research (CIFOR) have completed comprehensive studies on mangrove carbon in the South 

East Asia (SEA) and the Oceania (Donato and others 2011, Kauffman and others 2011) with 

financial support from the United States Agency for International Development (USAID) as 

part of its Sustainable Wetlands Adaptation and Mitigation Program (SWAMP). By drawing 

from the reported findings, lessons and experiences from SWAMP, inter-agency consortiums 

of academic and research institutions and conservation non-governmental organizations 

in Tanzania and Mozambique, with technical support from the USFS Center for Forested 

Wetlands Research and financial assistance of the USAID Africa Bureau, are developing the 

East Africa Mangrove Carbon Project (EAMCP). This initiative intends to support capacity 

development, advance scientific knowledge, and improve data collection in the areas of 

measurement and monitoring of carbon stocks and the impact of utilization and degradation 

in mangrove forests. Ultimately, EAMCP aims to provide scientific information and capacity 

to inform effective policy and management actions for the secured future of mangroves in 

East Africa. The consortium in Tanzania is utilizing the EAMCP opportunity to establish 

a mangrove research and demonstration forest in the Rufiji Delta (MRDF). This facility 

will be officially designated and sanctioned within the administering government agency, 

the Tanzania Forestry Service (TFS). The designation will entail recognition of the site as 

a special use area, where activities are aimed at research, demonstration, and training for 

capacity development of academic and scientific community, practitioners and managers, and 

communities.

1

Mwita Mangora, Lecturer in Mangrove Ecology and Management, Institute of Marine Sciences of University of Dar es Salaam, Zanzibar, Tanzania

Mwanahija Shalli, Lecturer in Coastal and Marine Socio-Economics, Institute of Marine Sciences of University of Dar es Salaam, Zanzibar, Tanzania

Immaculate Semesi, Lecturer in Coastal Ecology and Marine Biology, Department of Aquatic Sciences and Fisheries of University of Dar es Salaam, 

Dar es Salaam, Tanzania 

Marco Njana, PhD Student, Department of Forest Mensuration and Management, Sokoine University of Agriculture, Morogoro, Tanzania

Emmanuel Mwainunu, Research Scientist in Ecology and Forest Carbon, Directorate of Forest Production, Tanzania Forestry Research Institute (TAFORI), 

Kibaha, Tanzania

Jared Otieno, Assistant National Coordinator, Forest Resources Assessment and Monitoring, Tanzania Forest Services (TFS) Agency, Dar es Salaam, Tanzania

Elias Ntibasubile, Surveyor and Mapping Officer, Forest Resources Assessment and Monitoring, Tanzania Forest Services (TFS) Agency, Dar es Salaam, Tanzania 

Henry Mallya, Mangrove Officer, TFS Rufiji District Office, Kibiti Tanzania

Kusaga Mukama, REDD+ Project Coordinator, WWF Tanzania Country Office, Dar es Salaam,Tanzania

Matiko Wambura, Assistant District Forest Manager, TFS Rufiji District Office, Kibiti Tanzania

Nurdin Chamuya, National Coordinator, Forest Resources Assessment and Monitoring, Tanzania Forest Services (TFS) Agency, Dar es Salaam, Tanzania

Carl Trettin, Research Soil Scientist, USDA Forest Service Southern Research Station, Center for Forested Wetlands Research, Cordesville, SC 29434

Christina Stringer, Research Hydrologist, USDA Forest Service Southern Research Station, Center for Forested Wetlands Research, Cordesville, SC 29434
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 191

Linking Terrestrial and Marine Ecosystems

The Rufiji Delta, which is located about 150 km South of Dar es Salaam, contains the largest 

continuous mangrove forest in Tanzania and the region, comprising approximately 53,000 

ha (Semesi 1992). Eight of the 10 mangrove species occurring in Tanzania are found in the 

Delta (Wagner and Sallema-Mtui 2010). Over 150,000 people inhabit the Rufiji Delta and its 

floodplain, the majority of who subsist on traditional fishing, cultivation, and extraction of 

mangrove wood products. Most of the mangrove logging that feeds other part of Tanzania as 

far as the islands of Zanzibar is done within the Rufiji Delta. The Delta is characterized by 

traditional shifting cultivation of rice that involves clearance of mangrove areas in the upper 

reaches where freshwater flooding prevails. The delta supports the most important fishery 

in Tanzania’s coastline, accounting for about 80 percent of all wild-shrimp catches in the 

country (Masalu 2003). As one of the largest deltas containing the largest mangrove forest 

in East Africa, the Rufiji Delta offers an excellent site for research activities, allowing for 

ground-truthing of methodologies and management practices. The Delta provides a mangrove 

forest that is representative of the scale of a delta landscape, providing sufficient area for 

current and future uses, including long-term and large-scale experiments. The proposed area 

of about 9,200 ha of a single tract of mangrove forest is favorable for easy management and 

monitoring. The site includes the present main distributary of the Rufiji River, and other 

smaller branches and creeks, provide the capability to consider mangroves in a variety of both 

geomorphic and hydrologic settings. As the majority of mangrove species known to occur in 

Tanzania are found in the Delta, the area provides the opportunity to study each of the species, 

individually and in association with the other species. The site incorporates both a salinity 

and geomorphic gradient from the ocean front to freshwater floodplain margin. Freshwater 

areas are those where mangrove conversion to agricultural use is practiced. As such, it offers 

the possibility to address issues across a full environmental gradient, including agricultural 

Figure 1— Approximate delineation of the MRDF in the north Rufiji Delta.
192 Headwaters to Estuaries: Advances in Watershed Science and Management

Linking Terrestrial and Marine Ecosystems

impacts and mangrove management demonstrations like site restoration of abandoned and 

existing agricultural lands, as well as feasibility considerations of limited use. The proposed 

site includes harvesting disturbance that could be used for research. The presence of wood 

cutters provides an opportunity to engage them to develop and test sustainable management 

practices like comparing the impacts of selective and clear cutting. The proposed site is 

readily accessible, and is adjacent to an existing field station at Nyamisati Village that will 

facilitate operational logistics related to research and training, including availability of office 

space, stores, boats and local laborers, and lodging accommodations. The field station has a 

great potential of being elevated to a regional mangrove information center.

The MRDF has three core objectives: 1) To improve, share and apply scientific knowledge 

on assessment of carbon stocks, restoration and sustainable use to support the conservation 

of mangrove ecosystems; 2) To strengthen and build capacity for integrated mangrove 

management institutions and strategies, and empower dependent local communities to engage 

in decision-making and management that conserves, restores and sustainably uses mangrove 

ecosystems; and 3) To enhance mangrove forest resource governance by encouraging 

integrated management programs and conservation investments that are ecologically and 

socio-economically sound. The general approach for the MRDF is to develop mangrove 

assessment and monitoring capabilities, implement experiments and develop tools to address 

utilization and management issues. Presently, research on mangrove ecosystems is derived 

from individual studies, usually conducted on independent sites. Accordingly, there is no 

basis for accumulating information from individual studies on a given forest site. When 

studies are conducted on the same forest area there is greater efficiency in the work and 

investigators are able to address more complex questions because of the linkages to other 

studies on the same site. A common research area also provides an excellent basis for 

management demonstrations (e.g. silvicultural practices) and training activities because of 

the well-established interdisciplinary data sets that can be made available. Establishment of 

this research forest has a high-likelihood for persistence after the initial project; properly 

implemented, the facility will leverage additional projects.

ACKNOWLEDGMENTS

This work was made possible through funding provided 

by the US AID Africa Bureau and the management of the 

USDA Forest Service International Programs Office.

LITERATURE CITED

Donato, D.C.; Kauffman, J.B.; Murdiyarso, D.; Kurnianto, S.; 

Stidham, M. 2011. Mangroves among the most carbon-rich 

tropical forests and key in land use carbon emissions. Nature 

Geosciences, 4: 293- 297.

Kauffman, J.B.; Heider, C.; Cole, T. G.; Dwire, K. A.; Donato 

D.C. 2011. Ecosystem carbon stocks of Micronesian 

mangrove forests. Wetlands, 31:343–352.

Masalu, D.C.P. 2003. Challenges of coastal area management 

in coastal developing countries—lessons from the proposed 

Rufiji delta prawn farming project, Tanzania. Ocean & 

Coastal Management, 46: 175–188.

Semesi, A.K. 1992. Developing management plans for 

the mangrove forest reserves of mainland Tanzania. 

Hydrobiologia, 247: 1-10.

Wagner G.M.; Sallema-Mtui R. 2010. Change analysis of RufijiMafia-Kilwa mangroves, Tanzania in relation to climate 

change factors and anthropogenic pressures. WWF US/

GEF Coastal Resilience to Climate Change Project. WWF 

Tanzania Country Office, Dar es Salaam. 158 p.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 193

Linking Terrestrial and Marine Ecosystems

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATERSHED MANAGEMENT TO SUPPORT 

CORAL REEF RECOVERY AND RESILIENCY

Lisa Vandiver, Tom Moore, Sean Griffin, Michael Nemeth, Rob Ferguson1

Coral reef habitats in the Caribbean region have experienced significant reductions in 

abundance over the past several decades. These declines are due to both global stressors, such 

as increases in sea surface temperatures and ocean acidification, and localized stressors, such 

as land-based sources of pollution (LBSPs). Climate change has led to increased occurrence 

and extent of coral bleaching events, tropical storms and hurricanes, and coral disease. 

Management of these global threats is difficult; however, studies have shown that coral reef 

recovery and resilience can be enhanced by managing local nutrient and sediment stressors. 

Over the past decade, NOAA has taken a leading role in the abatement LBSPs to support 

recovery, enhancement, and resiliency of coral habitats in the Caribbean.

This presentation will provide an overview of the watershed management techniques that 

NOAA’s Restoration Center and NOAA’s Coral Conservation Program have utilized to 

combat LBSPs to protect and restore the seagrass and coral habitats in a priority region in 

the Caribbean: Culebra, Puerto Rico. Culebra is a small island, approximately 11.6 square 

miles, off the northeast coast of Puerto Rico. This island is surrounded by relatively healthy 

coral and seagrass habitats; however in the past decade scientists have reported a 20 to 40 

percent decline in live coral cover in certain portions of the island that are suspected to be 

linked to LBSPs. In 2010, a group of regional experts identified Culebra as a priority for 

coral reef conservation. Since then NOAA has partnered with federal agencies, jurisdictional 

agencies, and local stakeholders to develop a watershed management plan to identify sources 

of pollution and prioritize LBSP management actions for the island. This plan has served 

as a means of prioritizing the implementation of LBSP management actions on Culebra. In 

addition, this summer studies were initiated to establish baselines for nearshore water quality 

and seagrass and coral health. This information, combined with research of the management 

practices themselves, will provide resource managers the information needed to evaluate the 

performance of the LBSP management actions and inform adaptive management strategies.

1

Lisa Vandiver, Marine Habitat Restoration Specialist, ERT Contractor for NOAA Restoration Center, Charleston, SC 29405

Tom Moore, Marine Habitat Restoration Specialist, NOAA Restoration Center, St. Petersburg, FL 33701

Sean Griffin, Coral Reef Restoration Specialist, ERT contractor for NOAA Restoration Center, USCG Air Station Borinquen, Aguadilla, PR 00603

Michael Nemeth, Coral Reef Restoration Specialist, ERT contractor for NOAA Restoration Center, USCG Air Station Borinquen, Aguadilla, PR 00603

Rob Ferguson, Coral Reef Watershed Management Specialist, TBG contractor for NOAA Coral Reef Conservation Program, Boquerón, PR 00622
194 Headwaters to Estuaries: Advances in Watershed Science and Management

Linking Terrestrial and Marine Ecosystems

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATERSHED PROCESSES FROM RIDGE TO REEF: 

CONSEQUENCES OF FERAL UNGULATES FOR CORAL REEF 

AND EFFECTS OF WATERSHED MANAGEMENT

Gordon Tribble, Jonathan Stock, Jim Jacobi1

Molokai’s south shore has some of Hawaii’s most extensive and best-developed coral reefs. 

Historic terrigenous sedimentation appears to have impacted coral growth along several 

miles of fringing reef. The land upslope of the reef consists of small watersheds with 

streams that flow intermittently to the ocean. A USGS gage at the outlet of one of the most 

impacted watersheds (Kawela) recorded an average suspended sediment discharge of 1350 

tons per square mile between 2006 and 2011. Approximately one-half of the total annual 

suspended sediment was delivered during one day per year. Once delivered to coastal waters, 

the sediment persists for many years and is re-suspended approximately 300 days per year. 

Geomorphic mapping, high resolution photography, and field surveys were used to map 

vegetation and erosive processes throughout the Kawela watershed. The surveys revealed 

denuded areas at mid-elevations in the watershed eroding at rates approaching 16 mm/year. 

This denudation and subsequent erosion is attributed to large recent populations of feral goats 

and previously by cattle. In 2006, a rapidly-eroding site was selected to monitor rainfall, 

runoff, erosion and vegetative cover. Intensive culling of goats by land managers began 

three years later (2009). From 2009 to 2014 a marked increase in vegetation was observed. 

Dry-season vegetation cover increased approximately from 3 percent to 15 percent and wetseason cover increased approximately from 28 percent to 68 percent. In addition, the nature 

of the vegetation changed from heavily grazed grasses and stunted shrubs to a much lusher 

foliage with an increase in native shrubs. During that same time period, the rate of erosion 

at the site decreased from about 16mm/year to less than 5 mm/year. The results indicate that 

ungulate removal allowed rapid vegetation recovery and subsequent reduction of erosion. 

Continued ungulate control may reduce sediment loads to coastal waters and lead to a gradual 

improvement in water quality and coral cover.

1

Gordon Tribble, Director, Pacific Island Ecosystems Research Center, US Geological Survey, Hawaii National Park, HI 96718

Jonathan Stock, Research Geologist, US Geological Survey, Menlo Park, CA 94025

Jim Jacobi, Research Botanist, US Geological Survey, Hawaii National Park, HI 96718
Hydrology and Water Quality Modeling
196 Headwaters to Estuaries: Advances in Watershed Science and Management

Hydrology and Water Quality Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

LINKING STATISTICALLY- AND PHYSICALLY-BASED MODELS 

FOR IMPROVED STREAMFLOW SIMULATION IN GAGED 

AND UNGAGED WATERSHEDS

Jacob LaFontaine, Lauren Hay, Stacey Archfield, William Farmer, Julie Kiang1

The U.S. Geological Survey (USGS) has developed a National Hydrologic Model (NHM) 

to support coordinated, comprehensive and consistent hydrologic model development, and 

facilitate the application of hydrologic simulations within the continental US. The portion 

of the NHM located within the Gulf Coastal Plains and Ozarks Landscape Conservation 

Cooperative (GCPO LCC) is being used to test the feasibility of improving streamflow 

simulations in gaged and ungaged watersheds by linking statistically- and physically-based 

hydrologic models. The GCPO LCC covers part or all of 12 states and 5 sub-geographies, 

totaling approximately 726,000 km2, and is centered on the lower Mississippi Alluvial Valley. 

A total of 346 USGS streamgages in the GCPO LCC region were selected to evaluate the 

performance of this new calibration methodology for the period 1980 to 2013. Initially, the 

physically-based models are calibrated to measured streamflow data to provide a baseline 

for comparison. An enhanced calibration procedure then is used to calibrate the physicallybased models in the gaged and ungaged areas of the GCPO LCC using statistically-based 

estimates of streamflow. For this application, the calibration procedure is adjusted to address 

the limitations of the statistically generated time series to reproduce measured streamflow 

in gaged basins, primarily by incorporating error and bias estimates. As part of this effort, 

estimates of uncertainty in the model simulations are also computed for the gaged and 

ungaged watersheds.

1

Jacob LaFontaine, Hydrologist, US Geological Survey, Norcross, GA 30093

Lauren Hay, Research Hydrologist, US Geological Survey, Lakewood, CO 80225

Stacey Archfield, Research Hydrologist, US Geological Survey, Reston, VA 20192

William Farmer, Hydrologist, US Geological Survey, Reston, VA 20192

Julie Kiang, Hydrologist, US Geological Survey, Reston, VA 20192
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 197

Hydrology and Water Quality Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

BLIZZARDS TO HURRICANES: COMPUTER MODELING OF 

HYDROLOGY, WEATHERING, AND ISOTOPIC FRACTIONATION 

ACROSS HYDROCLIMATIC REGIONS

Richard MT Webb, David L Parkhurst1

The U.S. Geological Survey’s (USGS) Water, Energy, and Biogeochemical Model 

(WEBMOD) was used to simulate hydrology, weathering, and isotopic fractionation in the 

Andrews Creek watershed in Rocky Mountain National Park, Colorado and the Icacos River 

watershed in the Luquillo Experimental Forest, Puerto Rico. WEBMOD includes hydrologic 

modules derived from the USGS Precipitation Runoff Modeling System, the National Weather 

Service Hydro-17 snow model, and TOPMODEL. PHREEQC, a geochemical reaction model, 

is coupled with the hydrologic model to simulate the geochemical evolution of waters as 

they evaporate, mix, and react within the landscape. The two watersheds are at opposite ends 

of the hydroclimatic spectrum. Andrews Creek, with an average temperature near 1°C and 

average runoff of 90 cm/yr, drains water and snowmelt from the flank of the North American 

Continental Divide, whereas the Icacos River, with an average temperature exceeding 20°C 

and average runoff of 400 cm/yr, drains a tropical rain forest. And although the igneous 

intrusive rocks underlying the two watersheds are similar, the weathering rates are not. 

Hikers near Andrews Creek will often walk on bare granite, while those hiking through the 

Icacos watershed will be separated from the bedrock by several meters of heavily weathered 

saprolite. Variations in the stable isotopes of water measured in precipitation are also not 

similar. The δ18O values of rain falling on the continental divide are near -8 permil while the 

snow dumped by blizzards onto smiling skiers has δ18O values near -20 permil. In contrast, 

afternoon showers in Puerto Rico have δ18O near 0 permil while drenching rains during the 

passage of tropical depressions can have δ18O values less than -5 permil. WEBMOD succeeds 

at simulating observed variations in major ions and stable isotopes measured in surface water 

as a mixture of waters, gases, and ions exchanged between atmosphere and soils as they mix 

along various flowpaths on their way to the outlet. The model is a valuable tool for simulating 

variations in the quantity and quality of water in watersheds with diverse geology, climate, 

and ecology, and for investigating the response of watersheds to climate change, acid mine 

drainage, acid rain, biological transformations, and other chemical reactions.

1

Richard Webb, Research Hydrologist, US Geological Survey, Denver, CO 80225

David Parkhurst, Research Hydrologist, US Geological Suvery, Denver, CO 80225
198 Headwaters to Estuaries: Advances in Watershed Science and Management

Hydrology and Water Quality Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

A WATERSHED-BASED SPATIALLY-EXPLICIT DEMONSTRATION OF 

AN INTEGRATED ENVIRONMENTAL MODELING FRAMEWORK FOR 

ECOSYSTEM SERVICES IN THE COAL RIVER BASIN (WV, USA)

John M. Johnston, Mahlon C. Barber, Kurt Wolfe, Mike Galvin, Mike Cyterski, 

Rajbir Parmar, Luis Suárez1

We demonstrate a spatially-explicit regional assessment of current condition of aquatic 

ecoservices in the Coal River Basin (CRB), with limited sensitivity analysis for the 

atmospheric contaminant mercury. The integrated modeling framework (IMF) forecasts water 

quality and quantity, habitat suitability for aquatic biota, fish biomasses, population densities, 

productivities, and contamination by methylmercury in headwater watersheds. The CRB is an 

8-digit hydrologic unit watershed facing widespread land use change, and the IMF simulates 

a network of 97 stream segments using the SWAT watershed model, a watershed mercury 

loading model, the WASP fate and transport model, the PisCES fish community model, a 

fish habitat suitability model, the BASS fish community and bioaccumulation model, and an 

ecoservices post-processer. The application of these models was facilitated by the automated 

data retrieval and model setup tool D4EM and updated model wrappers and interfaces for data 

transfers between these models. Results for each stream segment demonstrate three distinct 

groupings for flow. Baseline IMF predictions for all ecoservices are provided for 1990–2010 

across all segments, with summary statistics compared to independent models and field data 

for the period 2001-2010 after model spin-up. Spin-up of the IMF is also addressed to reach 

dynamic steady state, corresponding to the age of the longest lived fish in the drainage.

1

John M. Johnston, Supervisory Ecologist, US Environmental Protection Agency, Athens, GA 30605

Mahlon C. Barber, Research Ecologist, US Environmental Protection Agency, Athens, GA 30605

Kurt Wolfe, Computer Engineer, US Environmental Protection Agency, Athens, GA 30605

Mike Galvin, Computer Scientist, US Environmental Protection Agency, Athens, GA 30605

Mike Cyterski, Research Ecologist, US Environmental Protection Agency, Athens, GA 30605

Rajbir Parmar, Computer Engineer, US Environmental Protection Agency, Athens, GA 30605

Luis Suárez, Research Pharmacologist, US Environmental Protection Agency, Athens, GA 30605
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 199

Hydrology and Water Quality Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATERSHED MODELING AND DEVELOPMENT OF ECOLOGICAL FLOWS 

IN THE APALACHICOLA-CHATTAHOOCHEE-FLINT RIVER BASIN, 

ALABAMA, FLORIDA, AND GEORGIA

William Hughes, Mary Freeman, Elliott Jones, John Jones, Jacob Lafontaine, 

Jaime Painter, Lynn Torak, Steve Walsh1

In Grant Parish, LA, increases in overstory basal area, canopy cover, and development of 

understory woody plants reduce over the last 50 years, the Apalachicola-ChattahoocheeFlint (ACF) Basin in Alabama, Florida, and Georgia has undergone extensive development 

of water resources for municipal and industrial supplies, power generation, and agriculture. 

Concurrent with this development, there has been increasing conflict over the use of water 

in the ACF system, resulting in legal battles over the rights to this valuable resource. The 

U.S. Geological Survey (USGS) is studying the ACF basin as part of the Department of 

Interior’s initiative titled “Water: Sustain and Manage America’s Resources for Tomorrow” 

(WaterSMART) that will provide improved water-availability information and develop new 

tools to support water management decisions. This federally funded, four-year study has three 

major components that build on USGS data collection and modeling capabilities: estimating 

water use, modeling surface and groundwater flow, and modeling ecological flow relations. 

The water use component will develop a site-specific database of water use for the ACF Basin, 

develop new methods for estimating agricultural withdrawals, and compile available wateruse projections. Calculations of net water use will be improved by obtaining information on 

interbasin transfers, determining septic-tank return flows, and estimating consumptive use by 

thermoelectric plants. The hydrologic modeling component will consist of a surface-water 

model for the entire ACF Basin using the USGS Precipitation-Runoff Modeling System 

(PRMS) and a MODFLOW groundwater model for the lower Chattahoochee and Flint River 

Basins. These models will be linked to provide improved simulation of groundwater/surfacewater interactions in the lower part of the Basin. The ecological flows component will use 

multi-state, multi-season ecological models to predict changes in fish and mussel species 

occupancy based on variations in flow conditions associated with climate change, land-use 

change, and changes in water withdrawals or discharges.

1

William Hughes, Supervisory Hydrologist, US Geological Survey, Norcross, GA 30093

Mary Freeman, Research Ecologist, US Geological Survey, Athens, GA 30602

Elliott Jones, Hydrologist, US Geological Survey, Norcross, GA 30093

John Jones, Research Geographer, US Geological Survey, Reston, VA 20192

Jacob Lafontaine, Hydrologist, US Geological Survey, Norcross, GA 30093

Jaime Painter, Geographer, US Geological Survey, Norcross, GA 30093

Lynn Torak, Hydrologist, US Geological Survey, Norcross, GA 30093

Steve Walsh, Research Fish Biologist, US Geological Survey, Gainesville, FL 32653
200 Headwaters to Estuaries: Advances in Watershed Science and Management

Hydrology and Water Quality Modeling

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

INTERANNUAL VARIABILITY IN THE EXTENT OF WETLAND-STREAM 

CONNECTIVITY WITHIN THE PRAIRIE POTHOLE REGION

Melanie Vanderhoof, Laurie Alexander1

The degree of hydrological connectivity between wetland systems and downstream 

receiving waters can be expected to influence the volume and variability of stream discharge. 

The Prairie Pothole Region contains a high density of depressional wetland features, a 

consequence of glacial retreat. Spatial variability in wetland density, drainage evolution, 

and precipitation patterns as well as interannual and interdecadal variability in climate can 

be expected to result in variable degrees of wetland-stream connectivity within the region. 

Although numerous studies have examined how interannual variation in wetland water level 

influence available waterfowl habitat within this region, very few studies have explicitly 

examined how this variability in water level might influence the degree of surface water 

connectivity between wetlands or between wetlands and streams within this region. This study 

utilized a time series analysis of Landsat images (1990-2011) to map interannual variability 

in patterns of inundations and wetland-stream connectivity by fusing static data sources (e.g. 

NWI, NHD) with dynamic data sources (e.g. Landsat). Changes in the degree of wetlandstream connectivity were related to temporal variability in wetness conditions using drought 

indices and stream gauge data, as well as spatial variability in geology, as characterized by 

the U.S. EPA ecoregions, which influence wetland and stream density. We found that both the 

area of inundation and the degree of wetland-stream connectivity was correlated with climate 

conditions, and that the degree of wetland-stream connectivity varied between ecoregions. An 

improved understanding of wetland-stream connectivity within landscapes that contain a high 

density of depressional wetlands is critical to improve our predictions of stream flow and our 

understanding of how water moves through watersheds. Disclaimer: authors views expressed 

here do not necessarily reflect views or policies of USEPA.

1

Melanie Vanderhoof, ORISE Post-Doctoral Fellow, US Environmental Protection Agency, Washington, DC 20460

Laurie Alexander, Research Ecologist, US Environmental Protection Agency, Washington, DC 20460
Tidal Freshwater Rivers and Creeks - 

Do They Influence Terrestrial Ecosystem Functions
202 Headwaters to Estuaries: Advances in Watershed Science and Management

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

UNDERSTANDING THE LINKAGES BETWEEN A TIDAL 

FRESHWATER FORESTED WETLAND AND AN ADJOINING 

BOTTOMLAND HARDWOOD FOREST

Brooke Czwartacki, Carl C. Trettin, Timothy J. Callahan1

The low-gradient coastal topography of the southeastern Atlantic Coastal Plain, coupled 

with large oceanic tidal amplitudes cause rivers that discharge to the coast to exhibit tidal 

influence of tides far inland. In those reaches, tidal-freshwater forested wetlands (TFFW) 

occupy floodplains which eventually transition to non-tidal, bottomland hardwood-forested 

ecosystems. Hydrodynamic studies have not adequately addressed the upland boundary of 

TFFWs, where the hydrologic regime shifts from tidal-to fluvial-dominated processes as a 

result of a deceasing tidal gradient. Understanding how the tide influences those upper reaches 

is fundamental to understanding how rising sea-level may influence wetland dynamics. In this 

study, we investigated the following questions: (i) how, and to what extent, does the tidalfreshwater stream influence the shallow groundwater in the riparian zone; and (ii) how does 

the vegetation community differ in riparian zones of tidal-freshwater streams as compared to 

adjacent non-tidal systems. To address these questions, we collected hydrology and vegetation 

information in a fourth order stream, Huger Creek and its non-tidal tributary, Turkey Creek 

(USGS gage ID 02172035), in the Santee Experimental Forest near Cordesville, South 

Carolina. These streams form the headwaters of the East Branch of the Cooper River, which 

flows into the Charleston Harbor estuary. Information was collected over an eighteen-month 

period from monitoring gages in Huger and Turkey Creeks, from water-table wells in the 

riparian wetlands, and from vegetation surveys in riparian zone plots. Our analysis indicates: 

(i) that the water-table gradient is “upstream” and the tidal pulse affects the shallow ground 

water table, and (ii) that the forest-community structure showed no significant relationship 

to tidal vs. non-tidal hydrodynamics in the riparian zones. These results emphasize the 

need to assess ecology and hydrology characteristics of tidal-freshwater forested wetland 

systems separately from non-tidal systems because of the tidal regulation of the water budget. 

Considering that rising sea level will affect large areas of the coast with low topographic 

gradients, existing TFFW systems should be inundated. As a result, upstream non-tidal zones 

will soon be affected by tides due to rising seas. Improved understanding of the linkages 

across the interface of tidal and non-tidal terrestrial ecosystems will provide valuable 

information to decision makers and is needed to anticipate long-term ecological resiliency 

during higher sea levels.

1

Brook Czwartacki, Hydrologist, Earth Science Group, South Carolina Department of Natural Resources, Charleston, SC 29412 

Carl C. Trettin, Research Soil Scientist, Center for Forested Wetlands Research, USDA Forest Service, Cordesville, SC 29434

Timothy J. Callahan, Professor, Graduate Program in Environmental Studies, College of Charleston, Charleston, SC 29424
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 203

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

BIOGEOCHEMICAL AND SURFACE ELEVATION CONTROLS OVER 

TIDALLY INFLUENCED FRESHWATER FORESTED WETLANDS 

AS THEY TRANSITION TO MARSH

William Conner, Ken W. Krauss, Gregory B. Noe, Jamie A. Duberstein, 

Nicole Cormier, Camille L. Stagg1

Many coastal ecosystems along the south Atlantic are transitioning from forested wetlands 

to marsh due to increasing tidal inundation and saltwater intrusion primarily attributed to 

global climate change processes. In 2004, we established long-term research sites in Georgia, 

South Carolina, and Louisiana to understand how climate factors (temperature, precipitation, 

streamflow, sea-level rise, droughts, and hurricanes) interact to elevate soil salinities and 

flooding that collectively foster forest dieback and habitat conversion in tidal freshwater 

forested wetlands of the Southeast. We have documented changes in forest structure and 

growth of trees in swamps of South Carolina, Georgia, and Louisiana from 1988-2014 

subjects to a variety of flooding regimes. We found that as estuarine influence shifts inland 

with sea-level rise, forest growth becomes linked to salinity and salinity-induced changes in 

nutrient availability. While litterfall estimates seem to be well defined with 3–5 years of data, 

stem growth across hydrological gradients in some areas are still not clear even with 10 years 

of data. We found that salinity, soil total nitrogen, flood duration, and flood frequency affect 

forest diameter increment, litterfall, and basal area the greatest, and in predictable ways. Even 

small concentrations of salinity (e.g., < 2 g/L) can drastically decrease basal area increment 

growth rates and litterfall production, lead to increased nitrogen mineralization, and reduce 

surface elevation in these intertidal forests with inherently low sedimentation rates and thereby 

exacerbate encroachment of marsh vegetation. Conversion to oligohaline marsh is associated 

with increased sediment nutrient inputs that may then increase herbaceous productivity, 

further increase sediment trapping, and enhance the resilience of tidal wetland surface 

elevation to sea-level rise. These changes in soil nutrients can be slow to affect the ecosystem, 

but have long-lasting effects on productivity and permanent changes in the composition of 

forest stands. Based on long-term data, we will describe processes as determined from two 

primary river systems in the Southeast, and describe a way forward in understanding whether 

other river systems transition similarly with increasing salinity.

1

William Conner, Professor, Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, SC 29442

Ken Krauss, Research Ecologist, US Geological Survey, Lafayette, LA 70506

Gregory Noe, Research Ecologist, US Geological Survey, Reston, VA 20192

Jamie Duberstein, Research Assistant Professor, Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, SC 29442

Nicole Cormier, Ecologist, US Geological Survey, Lafayette, LA 70506

Camille Stagg, Ecologist, US Geological Survey, Lafayette, LA 70506
204 Headwaters to Estuaries: Advances in Watershed Science and Management

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

TRACKING SALINITY INTRUSIONS IN A COASTAL FORESTED 

FRESHWATER WETLAND SYSTEM

Anand D. Jayakaran, Thomas M. Williams, and William H. Conner1

Coastal forested freshwater wetlands are sentinel sites for salinity intrusions associated with 

large, tidally influenced, storm-driven or drought-induced incursions of estuarine waters 

into freshwater ecosystems. These incursions may also be exacerbated by rising sea levels 

associated with climate change. A coastal forested freshwater wetland in South Carolina 

- Strawberry Swamp - has experienced dieback of freshwater forested wetland trees due 

to increased salinity levels within the wetland (Williams et al. 2012). Strawberry Swamp 

comprises a drainage area of 236 hectares at its outlet into the tidal creek. Ground elevations 

in the watershed range from mean sea level (MSL) at its outlet to 1.5 m above MSL at the 

watershed boundary. Historical aerial images of the swamp show considerable changes to 

forest structure vegetation through the last few decades (Williams et al. 2012, Jayakaran et al. 

2014). Vegetation in the wetland is transitioning from a closed canopy of common freshwater 

tree species such as bald cypress, water tupelo and swamp tupelo at its upper reaches to a 

more open canopy due to the establishment of salt tolerant grasses closer to the outlet. The 

wetland is prime habitat for several wildlife species and amphibians as evidenced by game 

cameras. The wetland drains into a tidal creek at its outlet through a pipe culvert; the tidal 

creek is connected to Winyah Bay which receives freshwater from the third largest watershed 

on the eastern coast ultimately discharging into the Atlantic Ocean. Tidal dynamics influence 

the wetland outlet, while at its upper sections, the water flows are driven by rainfall and 

topographical slope. Backwater effects from Winyah Bay also appear to impact flow dynamics 

at the wetland outlet when large river flows discharging into Winyah Bay force freshwater into 

tributary tidal creeks and swamps. A corollary to the phenomenon of high flows in the rivers 

is the influence of drought or low flow conditions in the rivers that results in the movement 

of the salt-freshwater wedge landward, causing increased salinity in the Bay and its tributary 

systems (tidal creeks and connected wetlands). In June 2013, water level, temperature, and 

conductivity sensors were installed along the salinity gradient to measure temporal variations 

in hydrologic conditions within the swamp. Microclimatic conditions were also measured and 

water flux at the tidally influenced watershed outlet was logged using an acoustic Doppler 

flow velocity sensor installed within the pipe culvert to measure bi-directional flows. At the 

upper extent of the watershed, a groundwater well was installed and instrumented with a 

depth, temperature conductivity sensor to characterize groundwater position and groundwater 

salinity. A conductivity temperature depth (CTD) sensor was also deployed within the tidal 

creek to measure water level and salinity changes in that section of the system. For the 

purposes of this extended abstract, data measured between June 2013 and January 2015 will 

be reported and discussed. 

Results from 16 months of monitoring salinity in Strawberry Swamp show a pronounced 

salinity gradient between the upper reaches of the swamp and its lowest tidally influenced 

section at the outlet with the highest salinities measured at the swamp outlet. The upper 

reaches of the swamp were influenced primarily by incident rainfall within the watershed, 

with salinity levels in the two healthy zones ranging from 0.2 to 1.5 PSU, while at the mid1

Anand Jayakaran, Associate Professor, Washington State University, Puyallup, WA 98371

Thomas Williams, Professor Emeritus, The Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, SC 29440

William Conner, Professor, The Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, SC 29440
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 205

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

Figure 1—Net daily flow volumes measured at Strawberry Swamp outlet between June 

2013 and January 2015 represented as vertical bars. Water level at the wetland outlet is 

depicted as a gray line and show the influence of tidal, backwater, and upland flow dynamics. 

Groundwater level measured at an upland location is shown with a purple line and represent 

water elevations above a datum that is 3.3m below the ground surface.

stressed zone, salinity ranged from 1.6 to 3.6 PSU. At the zone that is currently experiencing 

the most dieback of trees (stressed zone), salinity ranged from 3.3 to 7.0 PSU. At the outlet 

there appears to be a complex dynamic driven by tides, local rainfall, and estuarine backwater 

effects. Salinity ranged from 0.3 to 15.6 PSU over the period of record. The data show that 

average salinity in the outflow is marginally higher than the average inflow salinities. Flow 

measurements at the outlet suggest that the wetland exports that represents 7.9 percent of 

rainfall incident on the watershed (Table 1). Tidal flows at the outlet summed over a daily time 

step showed that there were consecutive days of net flow into the swamp (inflows) between 

Volume of 

water (m3

)

Volume expressed 

as depth per unit 

watershed area (mm)

Total Rainfall (mm) 

(10/2013 and 1/2015)

Rainfall runoff 

ratio (%)

Infl ow -285,981 -122

Outlow 583,435 249 1,602 7.9

Net fl ow 297,454 127

Table 1—Total infl ows and outfl ows measured at Strawberry Swamp outlet between 

June 2013 and January 2015. 
206 Headwaters to Estuaries: Advances in Watershed Science and Management

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

May and July 2014 as well as in November and December 2014 (Fig. 1). These periods appear 

to coincide with low groundwater levels in the watershed. However, this net inflow of water 

into the swamp does not appear to be repeated during another period of low groundwater 

elevation during November 2013. Data collection is ongoing and we hope to develop a clearer 

picture of flow and salinity fluxes in Strawberry Swamp.

LITERATURE CITED 

Jayakaran A. D., Williams T. M., Conner W. H., Hitchcock D. 

R., Song B., Chow A. T., and Smith E. M., 2014. Monitoring 

water quality changes in a forested freshwater wetland 

threatened by salinity. Proceedings of the 2014 South 

Carolina Water Resources Conference, held October 15-16, 

2014 at the Columbia Metropolitan Convention Center. 

Williams T. M., Chow A. T., Song B., 2012. Historical 

visualization evidence on forest-salt marsh transition in 

Winyah Bay, South Carolina: A retrospective study in sea 

level rise. Wetland Science and Practice 29(4): 5-17. 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 207

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

LINKING FRESHWATER TIDAL HYDROLOGY TO CARBON CYCLING 

IN BOTTOMLAND HARDWOOD WETLANDS

Carl C. Trettin, Brooke J. Czwartacki, Craig J. Allan, Devendra M. Amatya1

Abstract—Hydrology is recognized as one of the principal factors regulating soil biogeochemical processes in forested 

wetlands. However, the consequences of tidally mediated hydrology are seldom considered within forested wetlands that 

occur along tidal water bodies. These tidal water bodies may be either fresh or brackish, and the tidal streams function as 

a reservoir to sustain a shallow water table depth as compared to nontidal stream reaches. Accordingly, both the hydrology 

and water chemistry are expected to affect the forest carbon cycle; however, there are few studies to support this assertion. 

Hypotheses that are suggested by this hydrogeomorphic setting include greater net primary productivity and greenhouse 

gas emissions. However, given the persistent and dynamic high water table, it is important to consider micro-topography in 

quantifying greenhouse gas emissions, a functionality similar to boreal peatlands. A major constraint to assessing carbon 

cycle dynamics in tidally influenced forested wetlands is the lack of an accepted classification system and reliable spatial 

data base to indicate their spatial extent; this is particularly important for the upper tidal reaches where there is not a threat 

of changes in salinity associated with sea level rise. Advancing research to address this important part of the landscape is 

fundamental to addressing issues associated with sea level rise and the interaction of coastal development on estuaries.

INTRODUCTION

Tidal freshwater forested wetlands exist at the interface 

between marine and terrestrial ecosystems. Until 

recently, they have been overlooked by wetland scientists, 

perhaps because they have a hydrologic regime that is 

characterized by both marine and terrestrial influences. 

The American Geophysical Union (AGU) Chapman 

Conference–Hydrogeomorphic Feedbacks and Sea 

Level Rise in Tidal Freshwater River Ecosystems, held 

in Reston, VA, 13-16 November, 2012, highlighted 

the importance of these wetland ecosystems and the 

considerable uncertainties about their ecological 

functions, as well as the potential effects associated with 

sea level rise and climate change. The objective of this 

paper is to provide context for needed research on the 

carbon cycle in tidal freshwater forested wetlands because 

they are at the outlets of terrestrial watersheds that are 

inextricably linked to estuaries, and it is a landscape that 

is experiencing sustained development pressures. 

Tidal Freshwater Forested Wetlands

Tidal freshwater forested wetlands (TFFW) occur in 

floodplains situated near the coastal zone along freshwater 

rivers that are subject to tides. While water table depth and 

duration of inundation are the primary factors controlling 

vegetation patterns in wetlands (Rheinhardt and Hershner 

1992) along tidally influenced rivers and streams, salinity 

concentration intercedes and regulates vegetation zonation 

(Odum 1988). Salt marsh communities dominated by 

smooth cordgrass (Spartina alternafloras) and black 

needlerush (Juncus roemarianus) occur in estuarine 

riparian zones where salinity levels range from 5 to >30 

ppt. In the oligohaline (brackish) marsh (0.5–5 ppt) zone, 

smooth cordgrass and black needlerush are common, 

but big cordgrass (Spartina cynosuroides) is typically 

prominent and is often mixed with bulrush (Scirpus 

americana) and pickerelweed (Pontederia cordata) 

(Wiegert and Freeman 1990). The most significant shift 

in vegetative community composition occurs where 

salinity concentration is below 0.5 ppt; here, freshwater 

marsh vegetation includes spatterdock (Nuphar lutem), 

giant cutgrass (Zizaniopsis miliaceaes), wild rice (Zizania 

aquatica), smartweed (Polygonums spp.), cattail (Typha 

spp.), and rose mallow (Hibiscus moscheutos) (Odum and 

others 1984). 

Tidal freshwater forested wetlands exist in a narrow 

margin between the head of tide and freshwater marsh, 

and they are distinguished from nontidal forests by the 

presence of tide in the adjoining stream or river. Tidal 

freshwater forested wetlands support a broad range of 

bottomland hardwood communities ranging from bald 

cypress (Taxodium distichum) and water tupelo (Nyssa 

1

Carl Trettin, Research Soil Scientist, Center for Forested Wetlands Research, USDA Forest Service, Cordesville, SC 29434

Brooke Czwartacki, Hydrologist, Earth Science Group, South Carolina Department of Natural Resources, Charleston, SC 29412

Craig Allan, Professor and Chair, Department of Geography & Earth Sciences, University of North Carolina–Charlotte, Charlotte, NC 28223 

Devendra Amatya, Research Hydrologist, Center for Forested Wetlands Research, USDA Forest Service, Cordesville, SC 29434
208 Headwaters to Estuaries: Advances in Watershed Science and Management

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

aquatic) stands in floodplains that are regularly flooded 

and maintain nearly constant soil saturation, to oak 

(Quercus spp.) and gum (Nyssa sylvatica) stands that 

are seasonally flooded, closely resembling the nontidal 

bottomland hardwood communities further upstream 

(Conner and others 2007, Kroes and others 2007, Light 

and others 2002).

Distribution and Classification

The presence of salt-tolerant vegetation assists in 

defining the boundaries between saltwater, brackish, 

and freshwater vegetative communities, but locating 

the forested edge of the tidal zone is difficult due to 

the uninterrupted forest cover within the tidal/nontidal 

convergence zone (Day and others 2007). This uncertainty 

arises from multiple sources, including the lack of a welldefined classification system, inconsistent terminology, 

and lack of data on the head-of-tide. The current estimates 

of land area occupied by TFFW are based on a coastal 

county survey conducted by the National Oceanic and 

Atmospheric Administration (NOAA), which delineated 

tidal freshwater forests and marshes based on National 

Wetland Inventory (NWI) data (Field and others 1991). 

Thus, the estimate is likely conservative due to reliance 

solely on vegetative data in a system that is hydrologically 

complex (Doyle and others 2007). 

The most commonly used wetland classification system 

is the U.S. Fish and Wildlife Service’s Wetland and 

Deepwater Habitat Classification System, developed by 

NWI, which uses vegetative cover to distinguish between 

wetland types and classes (Cowardin and others 1979). 

Tidal freshwater forested wetlands are categorized as 

either riverine (in-channel) or palustrine, which are 

denoted tidal by a water regime modifier. Tidal freshwater 

swamps are defined as separate from the adjacent estuary 

system by a salinity threshold of less than 0.5 ppt, and 

their proximity to the open ocean. Estuarine wetlands 

are mostly open or only partially closed off to the ocean, 

where salinities can range from polyhaline (18–30 ppt) 

closest to the ocean, to mesohaline (5.0–18 ppt) further 

up the estuary (Cowardin and others 1979). The riverine 

classification relates primarily to the area between the 

banks of a stream channel and describes both in-channel 

and forested cover. Palustrine forested wetlands include 

wetlands dominated by trees. Riverine and palustrine 

classifications also apply to nontidal wetlands; therefore, 

a water regime modifier is used to denote wetlands 

subjected to a freshwater tide. In the tidal system, three 

main types of flooding regimes exist: subtidal, regularly 

flooded, and irregularly flooded. To avoid confusion 

with saline environments, the nontidal water regime 

modifiers are used with the addition of the word “tidal” 

to differentiate these systems from palustrine or riverine 

nontidal systems. The modifiers indicate wetland surface 

tidal inundation patterns and include permanently 

flooded-tidal (the land surface is exposed less than once 

daily), regularly flooded-tidal (land surface is exposed at 

least one time daily), and seasonally flooded-tidal (land 

surface is flooded less than daily) (Cowardin and others 

1979).

The tidal freshwater forested wetlands are most prominent 

along the Southeastern Atlantic lower Coastal Plain, 

where it is estimated that over 200,000 ha exist (Field and 

others 1991). However, considerable uncertainty exists 

in the estimates of TFFW area, in large part because 

of the inconsistent use of the tidal modifiers within the 

NWI. The majority of TFFW are concentrated along the 

coasts of the South Carolina, Georgia, Florida, Virginia, 

and Maryland, with smaller areas along the Gulf Coast 

and upper portions of the Atlantic Coastal Plain. South 

Carolina has the largest TFFW land area (estimated at 

over 40,000 ha) as a result of the relatively large tide 

range and low topographic gradient in the lower Coastal 

Plain.

DISCUSSION

Hydrology of Tidal Freshwater 

Forested Wetlands

Riparian wetlands exist at the interface of aquatic 

and terrestrial ecosystems, which are distinguished 

functionally by gradients of biophysical conditions, 

ecological functions, and biological communities (Batzer 

and Sharitz 2006). Their landscape position provides a 

hydrologic connection between water bodies and uplands 

due to proximity to rivers, streams, lakes, and estuary 

or marine environments. The main sources of water are 

precipitation, groundwater discharge, overland flow, 

interflow, and surface runoff from the adjacent water 

body (Batzer and Sharitz 2006). Riparian wetlands that 

occupy the freshwater (salinity <0.5 ppt) intertidal zone 

between nontidal forested riparian zones and freshwater 

marsh have a hydrologic regime that is subject to both 

tidal and fluvial influences. Accordingly, the water table 

in TFFW is affected by the adjoining tidal stream or river 

and is typically much wetter than upland riparian zones 

(Hackney and others 2007). 

Studying a TFFW riparian zone in the lower Coastal Plain 

of South Carolina, Czwartacki (2013) showed that the 

tidal freshwater stream functioned as a reservoir to sustain 

a higher mean water table within the tidally influenced 

riparian zone as compared to the nontidal bottomland 

hardwood wetland (table 1). Accordingly, the tidal stream 

reach sustains the water table, and during periods of low 

flow from the uplands (e.g., during summer and fall), the 

hydraulic gradient can be upstream (fig. 1). In addition to 

maintaining a higher water table, the hydroperiod within 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 209

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

the tidal riparian zone responds to the tidally mediated 

stream stage, especially within 30–50 m of the stream. 

Therefore, soil in tidal freshwater bottomland hardwood 

wetland may be characterized as being much wetter 

than a nontidal wetland, which suggests that the carbon 

dynamics would also be affected. 

Micro-topography 

Micro-topography is the undulating relief that is common 

to most forests, but particularly pronounced in wetlands, 

where it is typically described as hummocks and hollows. 

Hummocks are elevated areas (averaging +15 cm above 

base soil elevation). In contrast, hollows are bowlshaped depressions below the average wetland surface 

elevation, characterized by long periods of saturation 

that restrict plant growth (Courtwright and Findlay 

2011, Duberstein and Conner 2009). Micro-topography 

affects the available soil volume above the water table 

(fig. 2). Hollows are thought to increase flood duration 

and soil moisture through depression storage and affect 

the frequency and depth of flooding (Courtwright and 

Findlay 2011). Duberstein and Conner (2009) identified 

semi-diurnal tide signatures in groundwater hydrographs 

in old slough channels and found persistently saturated 

soil conditions despite drought conditions. Rheinhardt 

Figure  1  

Figure 1—Water table characterization in a tidal to nontidal stream reach, based on results 

presented by Czwartacki (2013) for Huger Creek, South Carolina.

Zone Mean water table depth 

below surface (cm)

Lower tidal 45

Mid-tidal 108

Upper Tidal 154

Nontidal 154

Table 1—Mean water table depth in the tidal transition 

zone and nontidal bottomland hardwood wetland 

over a 16-month period in 2011-2013 (from Czwartacki 

2013). Sites are arranged on a tidal gradient, with the 

far left being the lowest tidal site (LLT) and the far right 

being the nontidal site (NT-1).
210 Headwaters to Estuaries: Advances in Watershed Science and Management

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

and Hershner (1992) also reported that the tidal stream 

hydroperiod influenced the water regime in tidal-swamp 

hollows along the Pamunkey River, Virginia. In forested 

peatlands, micro-topography is recognized to affect 

carbon dynamics and greenhouse gas emissions (Trettin 

and others 2006). Taking into account that soil water 

regime is similarly influenced in the mineral soil of tidally 

influenced swamps, the expectation is that they will also 

exhibit a spatially complex soil gas emission pattern that 

is regulated by the distribution of the micro-topography 

and proximity to the tidal creek.

Carbon Dynamics in Tidal Freshwater 

Forested Wetlands

Carbon dynamics—and especially greenhouse gas 

emissions—in forested wetlands are strongly influenced 

by water table position (Trettin and Jurgensen 2003). 

Consequently, the contrasting hydrologic setting within 

tidal and nontidal freshwater riparian zones may be 

expected to alter carbon sequestration and fluxes (fig. 3). 

Wetland-dominated riparian zones have long been 

recognized as a primary source of carbon in waterborne 

fluxes of carbon in receiving streams (e.g., Doskey 

and Berch 1994, Harvey and Odum 1990, Harvey and 

others 1995). Although riparian soils are assumed to be 

the primary source of dissolved carbon compounds in 

adjacent receiving waters, more recent studies indicate 

that “fresh” vegetation decomposition products can make 

up the majority of dissolved organic carbon compounds 

found in tidally influenced stream channels (Engelhaupt 

and others 2001). Waterborne carbon transport and 

atmospheric losses in wetland-dominated riverine systems 

have been found to be dominated by dissolved inorganic 

carbon (DIC) transport and subsequent atmospheric loss 

through abiotic and/or microbial mediated processes 

(Elder and others 2000, Richey and others 2002.) 

The freshwater tidal stream functions as a reservoir of 

water that oscillates on a semidiurnal tidal cycle. During 

each semidiurnal tidal cycle, channels and rivulets 

within the riparian zone are inundated and subsequently 

drained, with the tidal stream being the source of the 

flood water and the receiving stream for the draining 

water. Correspondingly, there is a direct exchange of 

pore water in sediments within 2–3 m of the tidal stream 

(Nuttle and Hemond 1988), suggesting that dissolved 

constituents, including dissolved carbon and gases, and 

inorganic constituents are also exchanged. In many 

estuarine systems, there can be large changes in flow and 

water level on the tidal time scale (<13 hours); but, on 

extended time scales (day to weeks), there may be only 

small changes in net (tidally averaged) flow and water 

level during periods of low runoff from the uplands. In 

tidal creeks, like Huger Creek where there is seasonal 

freshwater flow from the uplands, the streamflow can 

be dominated by tidal inflows on the flood (incoming) 

and ebb (outgoing) tides during periods of low flow 

from the uplands. However, during periods of high flow 

from the uplands, flow from within the watershed may 

dominate the stream discharge. During low- or no-flow 

upland conditions, net flows will be negative (inland) with 

downstream source water, with a different water-quality 

signature, slowly moving upstream and exchanging with 

the upland water in the channel and riparian pore water. 

The residence time of downstream source water in these 

upper tidal reaches can last for long periods of time during 

drought periods, with high freshwater outflows required to 

flush the system to a more riverine-type condition.

Figure 2—Effect of micro-topography on soil volume.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 211

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

In nontidal wetlands, methane (CH4) efflux is regulated 

by the water table relative to the soil surface (Trettin and 

others 2006), with hummock positons having significantly 

lower emission rates than hollows (Bubier and others 

1993). Studying a bottomland tidal swamp in North 

Carolina, Megonigal and Schlesinger (2002) showed that 

tidal forcing on the riparian zone water table can regulate 

CH4 efflux from hollows. Accordingly, the net flux across 

an area of tidal riparian zone is likely an interaction 

among micro-topography and tidal forcing.

PERSPECTIVE

As a result of the high evapotranspiration demands of 

coastal forests (Amatya and Skaggs 2011, Domec and 

others 2012, Gholz and Clark 2002, Marion and others 

2013), many headwater watersheds exhibit ephemeral 

flow, being dry during the most of the growing season and 

having runoff in the fall or winter. Thus, the hydrologic 

flux from these upland watersheds and their associated 

riparian zones occurs in pulses during precipitationdriven flow events (Dai and others 2011, 2013; Epps and 

others 2013). In contrast, the tidal riparian reaches that 

occur lower in the landscape experience daily pulses of 

flooding and ebbing (rising and draining) waters, which 

can effectively import carbon and other constituents, as 

well as export materials from these riparian zones. The 

fluxes and associated mass balance of carbon within these 

forested wetlands that interface uplands and estuaries 

have not been measured. We hypothesize that carbon 

sequestration is higher in TFFWs as compared to an 

upstream nontidal forested wetland, and that carbon 

export is also larger (fig. 4). In tidally influenced riparian 

zones, available water should not limit productivity as 

compared to nontidal riparian zones that exhibit wide 

fluctuations in water table depth; correspondingly, 

export of organic matter will be facilitated by the daily 

inundations from the tidal stream.

Figure 3—Carbon cycle forested wetlands (adapted from Trettin and Jurgensen 2003) 

reflecting a nontidal and tidal hydrologic regime.
212 Headwaters to Estuaries: Advances in Watershed Science and Management

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

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Full-­‐%dal   Transi%on   Non-­‐%dal  

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table    

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214 Headwaters to Estuaries: Advances in Watershed Science and Management

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

DETERMINING VOLUME SENSITIVE WATERS IN 

BEAUFORT COUNTY, SC TIDAL CREEKS

Andrew Tweel, Denise Sanger, Anne Blair, John Leffler1

Non-point source pollution from stormwater runoff associated with large-scale land 

use changes threatens the integrity of ecologically and economically valuable estuarine 

ecosystems. Beaufort County, SC implemented volume-based stormwater regulations on the 

rationale that if volume discharge is controlled, contaminant loading will also be controlled. 

The County seeks to identify which of their tidal creeks and rivers and what portions of these 

waters are most sensitive to stormwater runoff. Through an ongoing collaborative process with 

county officials and concerned citizens, four watersheds of critical interest were instrumented 

with rain gauges and salinity sensor arrays to monitor the movement of freshwater down these 

systems from volume “sensitive” headwaters to volume “insensitive” downstream waters. 

The change in salinity was measured as the primary indicator of the volume of stormwater 

entering the estuarine ecosystem. Runoff analyses were complicated somewhat by significant 

tidal exchanges that alter estuarine salinities twice daily. Thirteen and twenty-five hour 

filters were applied to the salinity time series to isolate the stormwater impacts from tidal 

effects. Watersheds and sub-watersheds were ranked with regard to their relative stormwater 

volume sensitivity by comparing several salinity response parameters derived from the time 

series data. Stormwater runoff is also being modeled with the Stormwater Runoff Modeling 

System (SWARM) to estimate the expected runoff based on watershed area, land cover, 

soils, and slope. If the empirical and modeling approaches correlate well, SWARM will be 

used to model stormwater volume sensitivity in additional estuarine watersheds, as well as to 

project impacts of climate change and engineered stormwater retrofits on tidal creeks. This 

information will permit Beaufort County to focus policy and stormwater management actions 

on those portions of tidal creeks that are most sensitive to stormwater inputs.

1

Andrew Tweel, Marine Scientist, South Carolina Department of Natural Resources, Charleston, SC 29412 

Denise Sanger, Associate Marine Scientist, South Carolina Department of Natural Resources, Marine Resources Research Institute, 

Charleston, SC 29412

Anne Blair, Environmental Research Scientist, JHT, Inc., NOAA Hollings Marine Laboratory, Charleston, SC 29412

John Leffler, Research Coordinator, ACE Basin NERR, South Carolina Department of Natural Resources, Charleston, SC 29412
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 215

Tidal Freshwater Rivers and Creeks - Do They Influence Terrestrial Ecosystem Functions

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

STORMWATER RUNOFF IN WATERSHEDS: A SYSTEM FOR 

PREDICTING IMPACTS OF DEVELOPMENT AND CLIMATE CHANGE

Ann Blair, Denise Sanger, Susan Lovelace1

The Stormwater Runoff Modeling System (SWARM) enhances understanding of impacts of 

land-use and climate change on stormwater runoff in watersheds. We developed this singleevent system based on US Department of Agriculture, Natural Resources Conservation 

Service curve number and unit hydrograph methods. We tested SWARM using US Geological 

Survey discharge and rain data. Multi-site validations conducted for both undeveloped and 

developed watersheds support the robustness of our system in quantifying and simulating 

runoff: rainfall to runoff differences between measured and modeled volumes ranged from 

3 to 11 percent; r2 for hydrograph curves ranged from 0.82 to 0.98. Key applications of 

SWARM are: (1) comparing runoff among watersheds representing different environmental 

settings (e.g., levels of development, soil types, a range of sizes, topography); (2) evaluating 

and illustrating (singularly or in combination) effects of primary drivers of runoff amount 

and flashiness including development level, soil type, antecedent runoff conditions, rainfall 

amount; (3) predicting runoff under a range of development scenarios within a watershed; and 

(4) integrating effects of urbanization and projected climate change scenarios. User-friendly 

templates make SWARM a good tool for scientific research, for resource management and 

decision making, and for community science education. The modeling system supports 

investigations of social and economic impacts to communities as they plan for increased 

development and climate change. SWARM currently is used in several research projects 

including one led by South Carolina Department of Natural Resources / ACE Basin NERR to 

identify estuarine waterways sensitive to stormwater runoff volume in Beaufort County, SC. 

Although we calibrated SWARM specifically to the southeast coastal plain, it can be applied 

to other regions by recalibrating parameters and modifying calculation templates.

1

Anne Blair, Environmental Research Scientist, JHT, Inc., NOAA Hollings Marine Laboratory, Charleston, SC 29412

Denise Sanger, Associate Marine Scientist, South Carolina Department of Natural Resources, Marine Resources Research Institute, 

Charleston, SC 29412

Susan Lovelace, Assistant Director for Development and Extension, South Carolina Sea Grant Consortium, Charleston, SC 29401

Interdisciplinary Research in the Watersheds: 

A Forum for Team Players
218 Headwaters to Estuaries: Advances in Watershed Science and Management

Interdisciplinary Research in the Watersheds: A Forum for Team Players

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

SPATIO-TEMPORAL VARIATION IN DISTRIBUTION OF AQUATIC 

SPECIES AND THEIR HABITATS IN A RESERVOIR TRANSITION ZONE

Andrew Dolloff, Craig Roghair, Colin Krause, John Moran, 

Allison Cochran, Mel Warren, Susie Adams, Wendell Haag1

Dams convert riverine habitat to a series of reaches or zones where differences in flow, habitat, 

and biota, both downstream and in reservoirs, are obvious and well described. At the upstream 

extent of a reservoir, however, is a transitional reach or zone that contains characteristics of 

riverine habitat both in the upper reservoir and in tributaries connected to the reservoir. The 

total amount and quality of habitat within the transition zone depends on characteristics that 

vary greatly both seasonally and on shorter, often unpredictable time scales depending on 

dam operation and a combination of weather and climate. Relatively little is known about 

the persistence and resilience of biological communities in the transition zone. The Lewis 

Smith development impounds several major headwater tributaries in the Black Warrior River 

watershed, including two large tributaries flowing through the Bankhead National Forest in 

north Central Alabama: Sipsey Fork and Brushy Creek. Water levels upstream of the Lewis 

Smith development fluctuate seasonally up to 6 m and are highest in early spring and lowest 

in late fall or early winter. The watershed upstream of the Lewis Smith development is home 

to extremely diverse biological communities with at least 69 fish, 18 mussel, and 6 crayfish 

species, counting native, introduced, and exotic species, several of which are restricted to the 

Black Warrior River drainage or are species of conservation concern. Beginning in 2012, we 

partnered in a multi-year effort to describe habitat conditions and biological communities 

within transitional habitats in the Sipsey Fork and Brushy Creek watersheds. Overall project 

objectives are to: 1) delineate the extent and physical characteristics (structure, sediment, 

etc.) of transition zone and sub-zone habitats during both full and minimum pond levels, 2) 

describe the distribution of fish, crayfish and mussel species with an emphasis on Federal 

and State Threatened and Endangered species, and 3) assess the role of tributaries as refuge 

habitats. Fish, mussel, and crayfish distributions in Sipsey Fork and Brushy Creek appear to 

be related to habitat zones (impounded, transition, stream) and subzones (stream-run, runimpounded). In general, the transition zone functions as an ecotone, with the highest overall 

species diversity. Within the transition zone we collected species associated with river, stream, 

and headwater habitats more frequently from the stream-run subzone than the run-impounded 

subzone. Impounded and transitional habitats also function as pathways for upstream invasion 

by non-native fish, mussel, and crayfish species introduced into Lewis Smith reservoir. 

1

Andrew Dolloff, Supervisory Fishery Research Biologist, USDA Forest Service, Southern Research Station, Blacksburg, VA 24060

Craig Roghair, Fisheries Biologist, USDA Forest Service, Southern Research Station, Center for Aquatic Technology Transfer, Blacksburg, VA 24060

Colin Krause, Fisheries Biologist, USDA Forest Service, Southern Research Station, Center for Aquatic Technology Transfer, Blacksburg, VA 24060

John Moran, Fisheries Biologist, USDA Forest Service, National Forests in Alabama, Montgomery, AL 36107

Allison Cochran, Wildlife Biologist, Bankhead National Forest, Double Springs, AL 35553

Mel Warren, Aquatic Ecologist, USDA Forest Service, Southern Research Station, Oxford, MS 38655

Susie Adams, Research Fisheries Biologist, USDA Forest Service, Southern Research Station, Oxford, MS 38655

Wendell Haag, Research Fisheries Biologist, USDA Forest Service, Southern Research Station, Oxford, MS 38655
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 219

Interdisciplinary Research in the Watersheds: A Forum for Team Players

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ENVIRONMENTAL SUSTAINABILITY OF INTERCROPPING 

SWITCHGRASS IN A LOBLOLLY PINE FOREST

George Chescheir, François Birgand, Mohamed Youssef, 

Jami Nettles, Devendra Amatya1

A multi-institutional watershed study has been conducted since 2010 to quantify the 

environmental sustainability of planting switchgrass (Panicum virgatum L.) between wide 

rows of loblolly pine (Pinus taeda L.). The hypothesized advantage of this intercropping 

system is the production of biofuel feedstock to provide additional revenue in forested lands 

and to utilize land areas that could not otherwise be used for food production. Three paired 

watershed scale (8 to 27 ha) studies are being performed at three locations: Carteret County, 

NC, Greene County, AL and Calhoun County, MS. An additional study is being performed 

at the plot scale (0.8 ha plots) in Lenoir County, NC. Treatments on these studies are: 1) 

Young trees (1 – 6 yr) with standard forestry practice, 2) Young trees with switchgrass planted 

between rows, 3) switchgrass planted with no trees, and 4) mid-rotation (15 to 18 yr) trees 

with standard forestry practice. Each watershed is instrumented to automatically measure 

and record flow at the outlet, water table depths and soil moisture in the fields, and weather 

data. Flow proportional composite samples are collected at the watershed outlets and shallow 

groundwater samples are collected in the fields. Water quality samples are analyzed for nitrate 

(NO3

-

-N), ammonium (NO4

+-N), total Kjeldahl nitrogen (TKN), total suspended solids (TSS), 

total phosphorous (TP), and dissolved organic carbon (DOC). Reference evapotranspiration 

(REF-ET) and actual ET for each vegetation type is being estimated using remote-sensing 

satellite images and meteorological data. Models have been developed to predict ET and 

ET related parameters (temperature, stomatal conductance) using LandSat data. Field and 

watershed scale models have been modified to better simulate the hydrology, and nutrient 

and sediment loss from the different land-uses on the watersheds. DRAINMOD based 

models have been used for simulating the flat poorly-drained watersheds in NC and APEX 

and SWAT models have been used for simulating the upland watersheds (MS and AL). Other 

sustainability parameters (wildlife, stream biota, plant biodiversity, soil carbon, biomass crop 

productivity and operational safety) are also being measured and analyzed in the watershed 

and plot studies. The information and models resulting from this multi-disciplinary study will 

be used to develop best management practices to sustainably produce biofuel feedstock in a 

forestry setting.

1

George Chescheir, Research Associate Professor, Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, 

NC 27695

François Birgand, Associate Professor, Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695

Mohamed Youssef, Associate Professor, Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695

Jami Nettles, Research Hydrologist, Weyerhaeuser Company, Columbus, MS 39704

Devendra Amatya, Research Hydrologist, USDA Forest Service, Center for Forested Wetland Research, Cordesville, SC 29434
220 Headwaters to Estuaries: Advances in Watershed Science and Management

Interdisciplinary Research in the Watersheds: A Forum for Team Players

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

PREDICTING FISH POPULATION DYNAMICS WITH SPATIALLY 

EXPLICIT, INDIVIDUAL-BASED MODELS: INTEGRATION OF ECOLOGY, 

HYDROLOGY, GEOMORPHOLOGY AND MORE

Bret Harvey, Steve Railsback1

Many important watershed science and management problems involve interactions among 

biological and physical factors. For example, the persistence and productivity of highly 

valued stream fish populations are commonly influenced by interactions among hydrologic 

and thermal regimes, sediment routing, the effects of predators and competitors, and food 

availability. Human influences such as water diversions, restoration projects, introduced 

species and climate change commonly further influence and complicate watershed 

management questions. Spatially explicit, individual-based models have the potential to 

address this complexity by simulating the environment down to spatial scales relevant to 

individual animals, while incorporating influential temporal variation in key physical factors. 

In STREAM and in SALMO are individual-based models of trout and salmon that simulate 

networks of stream reaches using habitat cells on the scale of a few square meters and 

information on streamflow, water temperature and turbidity at daily or sub-daily time steps. 

These models have been applied at ~40 sites for purposes such as understanding effects 

of habitat variables and physical regimes, evaluating flow and temperature management 

alternatives, and assessing/forecasting effects of restoration projects. The development 

and application of such models requires expertise in ecology, behavior, hydrology, 

geomorphology, engineering, and software development, and the ability to quantify biological 

and physical variables at high frequency over long time periods. Because these models 

integrate the effects of many watershed processes on important biological resources, they 

can provide a clear framework for interdisciplinary research and focusing it on important 

management questions.

1

Bret Harvey, Research Fish Ecologist, USDA Forest Service, Pacific Southwest Research Station, Arcata, CA 95521

Steve Railsback, Adjunct Professor, Humboldt State University, Department of Mathematics, Arcata, CA 95521
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 221

Interdisciplinary Research in the Watersheds: A Forum for Team Players

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

MANAGEMENT OF RIPARIAN AND AQUATIC ECOSYSTEMS 

USING VARIABLE-WIDTH BUFFERS

Brian Pickard, Gordon H. Reeves, K. Norman Johnson1

Management of aquatic and riparian ecosystems is constrained because of the reliance on 

“off-the-shelf” and one-size-fits-all concepts and designs, rather than considering specific 

features and capabilities of the location of interest. As a result, use of fixed- width buffers that 

generally depend on stream size is the most common approach. This is easy to administer 

and apply, and along with lack of guidance for developing buffers and uncertainty about 

results of using variable-width buffers, development and application of a variable approach 

to management of riparian and aquatic ecosystems has been limited. However, new analysis 

tools, such as NetMap, and practices, such as tree tipping, and a growing understanding of 

how key ecological processes occur within a watershed allows for development of viable and 

practical alternative approaches to the fixed-width approach that are ecologically beneficial 

and cost-effective while providing potential opportunities for other management objectives. 

We developed an approach that recognizes the inherent variation in where ecological 

processes occur within a watershed as well as the capacity to provide productive habitat 

to establish the size of riparian buffers and the type, extent, and objectives of management 

activities at a particular location. More productive and ecologically important locations 

receive the largest buffer in which management is directed to solely achieving ecological 

goals. Locations that are less productive and more immune to management impacts have less 

area devoted to solely achieving ecological goals and more area for managing for ecological 

and other goals. We provide an example of the application of this approach on federally 

managed lands in western Oregon.

1

Brian Pickard, Research Assistant, College of Forestry, Oregon State University, Corvallis, OR 97331 

Gordon H. Reeves, Research Fish Biologist, USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331

K. Norman Johnson, University Distinguished Professor, College of Forestry, Oregon State University, Corvallis, OR 97331
222 Headwaters to Estuaries: Advances in Watershed Science and Management

Interdisciplinary Research in the Watersheds: A Forum for Team Players

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WILD SALMON RESPONSE TO NATURAL DISTURBANCE PROCESSES

Russell F. Thurow, John M. Buffington1

Dynamic landscapes are shaped by a variety of natural processes and disturbances operating 

across multiple temporal and spatial scales. Persistence of species in these dynamic 

environments is also a matter of scale: how do species dispersal and reproductive rates 

merge with the scales of disturbance? Across the Pacific Northwest, salmon populations have 

evolved with a complex set of natural disturbance patterns and processes creating and altering 

their essential habitats. In most watersheds, human activities have changed the disturbance 

regimes and compromised our ability to examine both the natural processes and salmon 

population responses. In this study, we evaluated wild Chinook salmon responses to natural 

disturbance processes in the Middle Fork Salmon River (MFSR), Idaho. The MFSR is a large 

wilderness basin where natural processes function relatively unimpeded by human activities. 

During the last 20 years, a series of fires have burned large portions of the MFSR basin. Those 

fires, followed by intense thunderstorms over some burned areas, have resulted in large debris 

flows that have altered salmon habitats within both the mainstem MFSR and several major 

tributaries. Over this same 20 year period, we have annually surveyed and geo-referenced the 

location of all Chinook salmon redds (spawning nests) across the entire MFSR basin. In this 

paper, we describe the mechanisms of debris flow creation and sediment routing, illustrate 

temporal and spatial responses of spawning Chinook salmon to natural patterns of habitat 

disturbance in the basin, assess the importance of salmon dispersal and habitat connectivity, 

and addresses how a changing climate may alter natural landscape dynamics. In particular, 

warming temperatures are expected to increase fire frequency and subsequent debris flows in 

the basin, while increased rain-on-snow events may cause more frequent avalanches, both of 

which input wood and sediment to the stream network. Field observations are coupled with 

sediment routing models to explore the consequences of these dynamic processes on salmon 

habitat over space and time. Inspection of larger-scale stream and basin morphology shows 

that these processes have been acting on this landscape for millennia and have had long-term 

effects on channel gradient, stream width, and associated salmon habitats. Consequently, the 

disturbance processes are not new, geomorphically or biologically, but rather their frequency 

and spatial extent are being altered by climate change. Although salmon have evolved with 

these disturbance processes, a key question is whether adaptation of native species can keep 

pace with rates of climate change and associated disturbance regimes.

1

Russell Thurow, Research Fisheries Biologist, USDA Forest Service, Rocky Mountain Research Station, Boise, ID 83702

John Buffington, Research Geomorphologist, USDA Forest Service, Rocky Mountain Research Station, Boise, ID 83702
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 223

Interdisciplinary Research in the Watersheds: A Forum for Team Players

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

AN ECOLOGICAL ASSESSMENT OF LAND USE IMPACTS IN 

SMALL WATERSHEDS OF THE CHESAPEAKE BAY

Andrew Leight, John Jacobs, Lonnie Gonsalves, Gretchen Messick, 

Shawn McLaughlin, Jay Lewis, Julianna Brush, Eric Daniels, 

Matthew Rhodes, Lewis Collier, Robert Wood1

The Chesapeake Bay, the nation’s largest estuary, remains in relatively poor condition 

despite intensive public and scientific attention. In order to better understand the stressors 

and impacts occurring in the Bay as a result of land management decisions we conducted 

an assessment of both habitat condition and organismal response in three small watersheds 

of the upper Bay. We selected watersheds with different types of land use (agricultural, 

suburban, mixed-use). We collected samples in Spring, Summer, and Fall over three years, 

including measurements of organism health over a wide range of biological organization – 

from molecular to community level. Some responses followed predictable trends, such as 

poor benthic community condition in the highly urbanized watershed. Less obvious were 

findings that indicated there may be tradeoffs in the response of some organisms to stressors. 

For example, fish abundance and fish health were inversely related, with high abundances and 

poor condition in the agriculturally dominated watershed and the opposite occurring in the 

highly developed watershed. Our findings also agree with other studies that have discovered 

greater impacts to habitat condition in small, headwater tributaries close to land-based sources 

than in the mainstem. We subsequently extended the study to three other watersheds in the 

Chesapeake Bay in order to examine the same suite of stressors and responses in lower 

salinity rivers and to increase our understanding of land use effects on estuarine conditions. 

We collaborated with various stakeholders to conduct the study and are engaged with them to 

discuss application of the findings. 

1

Andrew Leight, Research Fishery Biologist, NOAA National Ocean Service, National Centers for Coastal Ocean Science, Cooperative Oxford 

Laboratory, Oxford, MD 21601

John Jacobs, Research Fish Biologist, NOAA National Ocean Service, National Centers for Coastal Ocean Science, Cooperative Oxford Laboratory, 

Oxford, MD 21601

Lonnie Gonsalves, Research Ecologist, NOAA National Ocean Service, National Centers for Coastal Ocean Science, Cooperative Oxford 

Laboratory, Oxford, MD 21601

Gretchen Messick, Research Fishery Biologist, NOAA National Ocean Service, National Centers for Coastal Ocean Science, Cooperative Oxford 

Laboratory, Oxford, MD 21601

Shawn McLaughlin, Microbiologist, NOAA National Ocean Service, National Centers for Coastal Ocean Science, Cooperative Oxford Laboratory, 

Oxford, MD 21601

Jay Lewis, Research Fish Biologist, NOAA National Ocean Service, National Centers for Coastal Ocean Science, Cooperative Oxford Laboratory, 

Oxford, MD 21601

Julianna Brush, Biological Technician, JHT Inc., NOAA National Ocean Service, National Centers for Coastal Ocean Science, Cooperative Oxford 

Laboratory, Oxford, MD 21601

Eric Daniels, Senior Systems Administrator, ActionNet Inc., NOAA National Ocean Service, National Centers for Coastal Ocean Science, 

Cooperative Oxford Laboratory, Oxford, MD 21601

Matthew Rhodes, Biological Technician, JHT Inc., NOAA National Ocean Service, National Centers for Coastal Ocean Science, Cooperative 

Oxford Laboratory, Oxford, MD 21601

Lewis Collier, Training Specialist II, JHT Inc., NOAA National Ocean Service, National Centers for Coastal Ocean Science, Cooperative Oxford 

Laboratory, Oxford, MD 21601

Robert Wood, Ecologist, NOAA National Ocean Service, National Centers for Coastal Ocean Science, Cooperative Oxford Laboratory, Oxford, 

MD 21601

New Insights into Studies on 

Long Term Experimental Watersheds 

to Address Contemporary Emerging Issues 

(PART 3)
226 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

INSIGHTS FROM LONG-TERM RESEARCH ON THE 

FERNOW EXPERIMENTAL FOREST

Mary Beth Adams1

In 1951, five weirs were constructed in the mixed hardwood forests of the Fernow 

Experimental Forest and watershed research began. Specializing in long-term watershed 

scale manipulations, researchers at the Fernow have evaluated effects of various silvicultural 

practices on water yield, seasonal flow patterns, water quality and on ecosystem processes 

and ecosystem services. Experiments with fairly narrow initial hypotheses have attracted 

researchers from around the world to address issues far removed from timber harvesting and 

forest management. Considerable research has been dedicated to understanding the effects 

of air pollution, particularly acidic deposition, on forest ecosystems. This research has led to 

detailed studies on biogeochemical cycling in mixed species forests. New issues which have 

arisen and been added to the research portfolio are soil acidification, nitrogen saturation, base 

cation depletion, climate change, and severe storm effects. The Fernow is unusual because 

of the variability in nitrogen retention among its gaged watersheds. In particular, research on 

cycling of nitrogen in forested watersheds has been ongoing for many years at the Fernow. 

In the early years (1970s and early 1980s), fertilization studies suggested that nitrogen 

was limiting tree growth. Later watershed research documented that nitrogen appeared to 

be available in excess of biotic demand, suggesting that some stands on the Fernow were 

nitrogen-saturated. Long-term documentation of high rates of nitrogen (and sulfur) deposition, 

along with parallel monitoring of stream water chemistry from several gauged headwater 

streams, has revealed high rates of nitrate export, along with some of the lowest rates of 

nitrogen retention in the eastern U.S. The Fernow Watershed Acidification Study and the Fork 

Mountain Long Term Productivity Study have both evaluated the effects of elevated nitrogen 

additions on nutrient cycling, tree growth, soil chemistry, and a variety of other parameters. 

Still, there are interesting gaps in our understanding of ecosystem processes, such as nutrient 

cycling, that suggest additional research topics. 

1

Research Soil Scientist, USDA Forest Service, Northern Research Station, Morgantown, WV 26505
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 227

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

LONG-TERM HYDROLOGIC RESEARCH ON THE 

SAN DIMAS EXPERIMENTAL FOREST, SOUTHERN CALIFORNIA: 

LESSONS LEARNED AND FUTURE DIRECTIONS

Peter M. Wohlgemuth1

Abstract—The San Dimas Experimental Forest (SDEF) is located in the San Gabriel Mountains, about 45 km northeast 

of Los Angeles, California. The SDEF was originally established in 1934 to document and quantify the hydrologic cycle 

in semiarid uplands with intermittent headwater streams. New and innovative equipment was necessary to measure 

rainfall and streamflow in this mountainous terrain. Long-term monitoring has revealed a number of hydrologic patterns 

following land use change and wildfire. Water quality monitoring shows that the SDEF has had very high levels of nitrate 

due to its proximity to the heavily polluted Los Angeles Basin. These nitrate levels, which approach federal standards, are 

exacerbated by land use change and fire. In the future, evaluating the hydrologic response from climate change models and 

testing specific climate change predictions for southern California may be possible using the 80-year record of temperature, 

rainfall, and streamflow from the San Dimas Experimental Forest.

INTRODUCTION

The San Dimas Experimental Forest (SDEF) is a nearly 

7000 ha research preserve administered by the USDA 

Forest Service, Pacific Southwest Research Station, and 

has been the site of extensive hydrologic monitoring for 

over 80 years (Dunn and others 1988). Established in 

1934, the original mission of the SDEF was to quantify 

the water cycle in semiarid upland terrain and to 

determine if any extra water could be harvested to support 

agriculture and domestic water supply in the valleys 

below (Robinson 1980). With its headquarters at Tanbark 

Flat (34o 12’ N latitude, 117o 46’ W longitude), the SDEF 

is located in the San Gabriel Mountains, about 45 km 

northeast of Los Angeles, California (fig. 1).

The Experimental Forest and Range network can be 

considered a cornerstone of USDA Forest Service 

Research due primarily to the long-term datasets acquired 

from these reserves. Long-term observations and 

monitoring can document subtle ecological shifts that are 

harbingers of environmental change not readily apparent 

from studies of only a few years duration. Furthermore, 

the effects of complex environmental processes or 

the response to land use changes or to management 

manipulations can only be fully appreciated over time.

In the early 1930s, the hydrologic cycle was fairly well 

understood in the humid eastern section of the United 

1

Physical Scientist, USDA Forest Service, Pacific Southwest Research Station, Riverside, CA 92507

Figure 1—Location map of the San Dimas 

Experimental Forest.
228 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

States where water was abundant. However, in the arid 

and semiarid West, water was scarce and watershed 

management was in its infant stages (Leopold and 

others 1964). Headwater streams were intermittent and 

rainfall-runoff relationships were virtually unknown. 

Long periods of drought were punctuated by large floods 

which destroyed property while millions of cubic meters 

of potentially usable water escaped to the sea. Because 

of the general scarcity and variability in water supply, 

wise watershed management depended on a better 

understanding of the water cycle in semiarid uplands. This 

prompted the establishment of the SDEF.

STUDY AREA

Elevations in the SDEF study area range from 450 to 1675 

m and topography consists of a highly dissected mountain 

block with steep hillside slopes and steep channel 

gradients. Bedrock geology is dominated by Precambrian 

metamorphics and Mesozoic granitics that produce 

shallow, azonal, coarse-textured soils (Dunn and others 

1988). The region experiences a Mediterranean-type 

climate, characterized by hot, dry summers and cool, wet 

winters. Temperatures range from -8o C to 40o C. Mean 

annual precipitation, falling almost exclusively as rain, 

is 715 mm in the SDEF (80-year record), but rain during 

individual years can range from 252 to 1848 mm. 

Native vegetation in the SDEF consists primarily of 

mixed chaparral, a dense shrubland of drought-tolerant 

plants 3-5 m in height. Plant cover on south-facing slopes 

ranges from closed stands of chamise (Adenostoma 

fasciculatum) and ceanothus (Ceanothus spp.) to more 

open stands of chamise and black sage (Salvia mellifera). 

North-facing hillsides are dominated by scrub oak 

(Quercus berberidifolia) and ceanothus, with occasional 

hardwood trees – coast live oak (Quercus agrifolia) and 

California laurel (Umbellularia californica) – occurring 

on moister shaded slopes and along the riparian corridors 

(Wohlgemuth 2006). Some pine-oak forest occurs in the 

higher elevations, especially on north-facing aspects, 

including canyon live oak (Quercus chrysolepis), big-cone 

Douglas-fir (Pseudotsuga macrocarpa), sugar pine (Pinus 

lambertiana), and a remnant grove of ponderosa pine 

(Pinus ponderosa).

Fire has been a part of the southern California landscape 

since before recorded history and is the disturbance event 

which drives much of the local environmental response 

(Sugihara and Barbour 2006). Fire alters the physical and 

chemical properties of the soil – bulk density and water 

repellency – promoting overland flow on the hillsides at 

the expense of infiltration (DeBano 1981). This water 

is quickly conveyed to the adjacent stream channels 

and flooding is a common post-fire hydrologic response 

(Krammes and Rice 1963). Stand-replacing wildfires 

occurred on the SDEF in 1919, 1960, and 2002.

One of the management treatments following the wildfire 

in 1960 was the type-conversion of the native chaparral 

vegetation in some watersheds to a mixture of perennial 

grasses. It was thought that type-conversion would aid 

in future fire control and would enhance water yield by 

replacing deep-rooted shrubs with shallow-rooted grasses 

(Rice and others 1965). These perennials included a 

variety of wheatgrass species (Agropyron spp.), Harding 

grass (Phalaris tuberosa var. stenoptera), big bluegrass 

(Poa ampla), smilo grass (Piptatherum miliaceum), and 

Blando brome (Bromus hordaceous) (Corbett and Green 

1965). Over time, many of the seeded grass species have 

disappeared from the sites and substantial amounts of 

buckwheat (Eriogonum fasciculatum) and black sage have 

established on the type-converted watersheds. 

METHODS

The hydrologic monitoring for this study was conducted 

in Volfe and Bell Canyons (fig. 1). Volfe Canyon 

watershed is 300 ha in size and covered with native 

chaparral vegetation. Volfe Canyon is a long-term 

reference watershed managed for minimal human 

disturbance. Bell Canyon consists of multiple headwater 

basins ranging in size from 25 to 40 ha. Originally 

covered with native chaparral vegetation, Bell2 was typeconverted to perennial grasses in 1958 and Bell1 was 

similarly converted in 1960 (Dunn and others 1988). Bell3 

remains in chaparral. 

Rainfall on the SDEF has been measured continuously 

since 1934 in a network of weighing raingages (Dunn and 

others 1988). Total annual rain for individual study areas 

was computed as the area-weighted average of the nearest 

stations measured in millimeters. Rainfall was assumed to 

be spatially uniform across the catchments and was also 

calculated as cubic meters based on watershed area. 

Streamflow has been measured in Volfe and Bell Canyons 

since 1938 (Dunn and others 1988). Stream discharge 

was measured in weirs for low flows (<50 L/s) and flumes 

for high flows. Stage heights were read from float-driven 

stream charts at 6 hour intervals and at inflection points 

during storm events. Discharge was computed from stage 

height using rating curves developed for each instrument 

and summed over the time intervals to get an annual water 

yield in cubic meters. 

Water quality has been measured in Volfe and Bell 

Canyons since 1986. Pumping samplers draw aliquots of 

stream water every 6 hours while the creeks are flowing. 

Samples are analyzed in the laboratory using an ion 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 229

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

chromatograph with detection limits of 0.01 ppm. Nitrate 

(NO3) is the primary analyte.

RESULTS AND DISCUSSION

Equipment Development

During the 1930s and 1940s, much time and effort were 

spent developing equipment to measure the various 

hydrologic components at SDEF. On mountainous terrain, 

a more accurate measurement of rainfall was realized 

if the gage was tilted perpendicular to the hillside slope 

rather than set in a vertical orientation (Hamilton 1954). 

Streamflow was intermittent, flashy, and often heavily 

bulked with sediment. Several tiers of weirs and flumes 

were necessary to accurately measure the range of 

expected discharges from the larger watersheds: a 90o

weir in the throat of a 0.91 m (three-foot) flume nested 

in a 2.44 m (eight-foot) flume. Moreover, a supercritical 

flume was developed – the San Dimas flume – capable 

of measuring flows containing considerable sediment 

and debris (Wilm and others 1938). A large lysimeter 

complex was built to quantify soil moisture, percolation, 

and evapotranspiration (Patric 1961), although this 

apparatus suffered from significant design flaws and was 

subsequently abandoned.

Fire Response

Post-fire flooding has long been documented in southern 

California (Kraebel 1934). Using the rainfall and runoff 

records from SDEF, this post-burn hydrologic response 

can be quantified and compared to pre-fire values. Storm 

rainfall, peak flows, and resulting flow volumes for Volfe 

Canyon watershed are shown in table 1. Prior to the 1960 

wildfire, the response to these early season moderate 

rainfall events is modest. However, the first four storms 

following the wildfire shows a spectacular contrast. Both 

peak flows and flow volumes increase by four orders of 

magnitude compared to pre-fire levels from similar storms 

(table 1). From these before and after hydrologic findings 

from the SDEF, the downstream damage to human 

communities by flooding following a wildfire in southern 

California can be easily explained.

Type-Conversion

Runoff records from the multiple small watersheds in 

Bell Canyon were used to assess the effects of typeconversion. None of the immediate post-fire years 

(1961-1964) were used in this analysis, eliminating the 

fire effects mentioned above. A test of normalcy using 

the Bell3 control watershed indicates a different runoff 

response trajectory between the pre- and post-conversion 

time periods (fig. 2). To account for this response 

difference, the runoff ratios (RO), the percentage of 

rainfall that leaves the watershed as streamflow (Ratzlaff 

1994), were calculated and the type-converted catchments 

were compared to the control. Bell1 watershed, which 

produced more runoff than Bell3 even prior to the 

vegetation change, increased its water yield by a factor 

of three following type-conversion (fig. 3). Bell2 had 

a similar response (fig. 4). Thus, type-conversion does 

appear to increase runoff and water yield from southern 

California chaparral watersheds. However, apart from 

the wholesale ecosystem changes and effects on native 

fauna, subsequent studies have shown that there are 

serious environmental consequences of type conversion, 

including increased erosion in the form of soil slips and 

slope failures (Rice and others 1969) and degraded water 

quality (Riggan and others 1985). 

Table 1—Rainfall, peak fl ows, and fl ow volumes from the Volfe Canyon watershed for similar 

storms before and after a wildfi re of July 1960.

Storm Dates Rainfall Peak fl ow Flow volume

mm L/s m3

Dec. 3-4, 1955 34.3 0.157 14

Oct. 19-21, 1958 27.4 0.116 2

Nov. 2-5, 1958 41.4 0.300 1

Jan. 11-12, 1960 36.1 0.068 2

Wildfi re – July 1960 

Oct. 9-10, 1960 21.3 3351 37,455

Nov. 3, 1960 36.8 370 48,060

Nov. 5-6, 1960 39.6 5538 55,258

Nov. 12, 1960 32.5 9347 412,037
230 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Figure 2—Rainfall-runoff relationships in Bell3 

watershed during the pre- and post-type-conversion 

time periods of Bell1 and Bell2 watersheds. The 

immediate post-fire years of 1961-1964 have been 

omitted from this analysis.

Figure 3—Runoff ratios (RO), the percentage of rainfall 

that leaves the watershed as streamflow, from Bell1 

pre- and post-conversion compared with RO from 

Bell3. Black dotted line is the line of one-to-one 

correspondence.

Figure 4—Runoff ratios (RO), the percentage of 

rainfall that leaves the watershed as streamflow, 

from Bell2 pre- and post-conversion compared 

with RO from Bell3. Black dotted line is the line 

of one-to-one correspondence.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 231

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Water Quality

Water quality sampling began sporadically in the early 

1980s and became a programmatic feature of SDEF 

monitoring in 1986. High rates of atmospheric N 

deposition are produced in southern California by chronic 

air pollution, primarily from automobile exhaust from the 

Los Angeles Basin. These pollutants become trapped in 

an inversion layer that gets pushed up against the inland 

mountains by daily onshore air flows from the Pacific 

Ocean. This deposition in the headwater mountains, 

including the SDEF, has led to measured surface water 

levels of nitrate that approach the Federal EPA standard 

of 10.0 mg L-1 for nitrate-N (Fenn and others 2003). 

Substantial amounts of nitrate are washed off shrub 

surfaces during the summer and autumn, when small 

storms are interspersed with pollution episodes. Measured 

stream water nitrate concentrations in the SDEF have 

been as high as 7.0 mg of nitrate-N L-1 in undisturbed 

native vegetation. These values are some of the highest 

measured rates in the United States and up to 1000 times 

greater than more pristine areas in southern California 

(Riggan and others 1985). Although there has been a 

slight decline in N deposition over the last twenty years 

with more stringent pollution control requirements, nitrate 

levels in SDEF stream water remain high (Meixner and 

others 2006). Fire can further increase nitrate levels in 

SDEF stream water. Initial data following a prescribed 

fire showed that nitrate-N concentrations in streams could 

be as much as 15.7 mg L-1, 1.5 times the Federal standard 

(Riggan and others 1985). Greater concentrations and 

yields of nitrate were also measured in watersheds that 

were type-converted to grasslands. Possibly, the greater 

nitrate levels reflected greater subsurface soil exposure 

caused by the landsliding in these altered landscapes 

coupled with the more rapid water flux through the 

shallow-rooted grasses. Maximum measured yield was 

19.4 Kg of N ha-1yr-1 in grass vegetation compared to 10.0 

Kg N ha-1yr-1 in chaparral (Riggan and others 1985). 

INTO THE FUTURE

If the model projections are correct, climate change will 

profoundly affect global weather patterns. Although 

there is considerable variability among the many models, 

the general consensus is that temperatures will increase 

and precipitation will decrease in most continental areas 

(Cayan et al. 2008). This will alter the local hydrologic 

cycle (the disposition of rain and snow, evaporation, 

transpiration, the timing of snowmelt, water storage) that 

will in turn affect water supplies. In southern California, 

the Mediterranean pattern of wet winters and dry 

summers is projected to continue. However, some models 

predict that the area could experience periods of up to 

30 years where annual rainfall is more than 10 percent 

below historical levels (Cayan et al. 2008), and the annual 

precipitation could decrease by 20 to 40 percent by the 

year 2100 (EPA 2013). One possible benefit of the longterm weather, rainfall, and stream runoff records at SDEF 

may be the ability to estimate the hydrologic response 

to expected climate change. Because of the natural 

variability inherent in any long-term dataset (e.g. figure 

2), surrogates for climate change scenarios may already 

exist in the SDEF archives. Thus, realistic estimates of 

hydrologic response could be used for planning purposes 

as well as to validate the output of climate change models. 

ACKNOWLEDGMENTS

To the visionaries who established the San Dimas 

Experiment Forest and to the dedicated cadre of scientists 

and technicians who stayed the course, thank you.

LITERATURE CITED

Cayan, D.R.; Maurer, C.P.; Dettinger, M.D. [and others]. 2008. 

Climate change scenarios for the California region. Climatic 

Change, 87(Supplement 1): S21-S42.

Corbett, E.S.; Green, L.R. 1965. Emergency revegetation 

to rehabilitate burned watersheds in southern California. 

Research Paper PSW-22. Berkeley: U.S. Department of 

Agriculture, Forest Service, Pacific Southwest Forest and 

Range Experiment Station. 14 p.

DeBano, L.F. 1981. Water repellent soils: A state-of-theart. General Technical Report PSW-46. Berkeley: U.S. 

Department of Agriculture, Forest Service, Pacific Southwest 

Forest and Range Experiment Station. 21 p. 

Dunn, P.H.; Barro, S.C.; Wells, W.G., II. [and others]. 1988. 

The San Dimas Experimental Forest: 50 years of research. 

General Technical Report PSW-104. Berkeley: U.S. 

Department of Agriculture, Forest Service, Pacific Southwest 

Forest and Range Experiment Station. 49 p.

Environmental Protection Agency. 2013. Climate impacts in the 

Southwest. http://www3.epa.gov/climatechange/impacts/

southwest.html [Date accessed: May 2015]

Fenn, M.E.; Baron, J.S.; Allen, E.B. [and others]. 2003. 

Ecological effects of nitrogen deposition in the western 

United States. BioScience. 53: 404-420.

Hamilton, E.L. 1954. Rainfall sampling on rugged terrain. 

Technical Bulletin No. 1096. Washington: U.S. Department 

of Agriculture. 41 p.

Kraebel, C.J. 1934. The La Crescenta flood. American Forests 

40:251-254, 286-287.

Krammes, J.S.; Rice, R.M. 1963. Effect of fire on the San 

Dimas Experimental Forest. In: Proceedings of Arizona’s 

7th Annual Watershed Symposium, September 18, 1963, 

pp. 31-34.

Leopold, L.B.; Wolman, M.G.; Miller, J.P. 1964. Fluvial 

Processes in Geomorphology. San Francisco: W.H. Freeman 

and Company. 522 p.
232 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Meixner, T.; Fenn, M.E.; Wohlgemuth, P.M. [and others]. 2006. 

N saturation symptoms in chaparral are not reversed by 

prescribed fire. Environmental Science and Technology. 

40(9): 2887-2894.

Patric, J.H. 1961. The San Dimas large lysimeters. Journal of 

Soil and Water Conservation. 16(1):13-17.

Ratzlaff, J.R. 1994. Mean annual precipitation, runoff, and 

runoff ratio for Kansas, 1971-1990. Transactions of the 

Kansas Academy of Science. 97: 94-101.

Rice, R.M.; Corbett, E.S.; Bailey, R.G. 1969. Soil slips related to 

vegetation, topography, and soil in southern California. Water 

Resources Research. 5(3): 647-659.

Rice, R.M.; Crouse, R.P.; Corbett, E.S. 1965. Emergency 

measures to control erosion after a fire on the San Dimas 

Experimental Forest. Miscellaneous Publication 970. 

Washington: U.S. Department of Agriculture. Pp. 123-130.

Riggan, P.J.; Lockwood, R.N.; Lopez, E.N. 1985. Deposition 

and processing of airborne nitrogen pollutants in 

Mediterranean-type ecosystems in southern California. 

Environmental Science and Technology. 19(9):781-789.

Robinson, J.W. 1980. A history of the Dalton and the San 

Dimas watersheds and the San Dimas Experimental 

Forest, Part I and II. Mt. San Antonio Historian. 

14(2): 47-77 and 14(3): 106-137.

Sugihara, N.G.; Barbour, M.G. 2006. Fire and California 

vegetation. In: Fire in California’s Ecosystems. Suguhara, 

N.G; van Wagtendonk, J.W.; Shaffer, K.E.; Fites-Kaufman, 

J.; Thode, A.E., eds. Berkeley: University of California Press. 

Chapter 1. Pp. 1-9.

Wilm, H.G.; Cotton, J.S.; Storey, H.C. 1938. Measurement 

of debris laden stream flow with critical-depth flumes. 

Tranactions of the American Society of Civil Engineers. 

103: 1237-1253.

Wohlgemuth, P.M. 2006. Hillslope erosion and small watershed 

sediment yield following a wildfire on the San Dimas 

Experimental Forest, southern California. In: Proc. 8th 

Federal Interagency Sedimentation Conference, Reno, 

NV, Interagency Advisory Committee on Water Data, 

Subcommittee on Sedimentation, Washington, D.C.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 233

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATER-LIMITING CONDITIONS BASED ON MONTHLY WATER 

BALANCES AND POTENTIAL EVAPOTRANSPIRATION AT PANOLA 

MOUNTAIN RESEARCH WATERSHED, GEORGIA, U.S.A.

Brent Aulenbach, Norman E. Peters, James Freer1

Drought and resulting water-limiting conditions can result in negative ecological impacts such 

as reduced plant growth and increased stress that can make plants more vulnerable to threats 

such as insect infestations. The long-term dataset at Panola Mountain Research Watershed, 

a small 0.41-hectare forested watershed near Atlanta, Georgia, U.S.A., was used to better 

quantify the important factors leading to water-limiting conditions. Actual evapotranspiration 

(ET) relative to potential ET (PET) was used as an indicator of water limiting conditions 

as PET represents the potential maximum ET, assuming no water limitations. Actual and 

potential ETs were compiled on a monthly basis for the period 1985 through 2011, which 

contains multiple drought periods. Potential ET was calculated from air temperature and solar 

radiation using the Priestley–Taylor equation. Actual ET was determined using the watershed 

water budget, and was calculated as the difference between monthly precipitation, runoff, and 

changes in water storage within the watershed. Water storage was determined using a water 

storage-baseflow relation developed for this watershed.

Annual water yields, the proportion of precipitation that occurs as runoff each year, varied 

greatly, ranging from 9.7 to 46 percent. The magnitude of water yields were largely dependent 

on the annual precipitation and whether the majority of precipitation occurred during the 

dormant season, resulting in more runoff, versus the growing season, resulting in more ET. 

Actual ET averaged about 40 millimeters per month (mm/month) during the dormant season 

and 88 mm/month during the growing season and peaked with an average of 123 mm/month 

in July. Actual ET averaged about 89 percent of PET during the dormant season and 70 

percent of PET during the growing season. For this analysis, we defined months with waterlimiting conditions as those where actual ET was <60 percent of PET. Months with waterlimiting conditions were observed during the growing season when monthly precipitation 

was low (defined as <50 mm) and was irrespective of watershed storage condition. This result 

may indicate that storage available in shallow soils derived from recent precipitation is a more 

important control on actual ET than overall watershed storage, with plant transpiration as the 

driver. The results of this analysis should assist in assessing the effects of future changes in 

seasonal and long-term climate patterns in precipitation on components of the water budget 

along with changes in the severity and duration of water-limiting conditions. 

1

Brent Aulenbach, Research Hydrologist, US Geological Survey, Norcross, GA 30093

Norman Peters, Hydrologist, US Geological Survey, Norcross, GA 30093

James Freer, Professor, School of Geographical Sciences, University of Bristol, Clifton, Bristol, UK
234 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

CHANGES IN BASEFLOW CONDITIONS OVER A 42 YEAR OBSERVATION 

PERIOD FOR THE LITTLE RIVER EXPERIMENTAL WATERSHED IN 

SOUTH GEORGIA

David D. Bosch, Randall G. Williams, Timothy C. Strickland, 

Jeff G. Arnold and Peter G. Allen1

Hydrology is the driving force of sediment, nutrient, and pesticide movement. Separation 

of streamflow hydrographs into rapid surface runoff and baseflow can vastly improve our 

understanding of chemical transport. In addition, characterizing these two components of 

streamflow can also greatly improve overall watershed hydrologic budgets which are critical 

for accurate evapotranspiration estimation. For validation of hydrology in model simulations, 

direct runoff and baseflow components of the streamflow hydrographs typically need to 

be separated. Incorrect representation of baseflow patterns can lead to erroneous results in 

watershed analysis. 

Here we examine annual and seasonal variations in baseflow within the Little River 

Experimental Watershed (LREW) from 1972 to 2013. The LREW is located near Tifton, 

Georgia, in the South Atlantic Coastal Plain of the U.S.A. (N31°26’13”, W83°35’17”). The 

LREW is part of the Gulf Atlantic Coastal Plain LTAR (Maddox 2013). The hydrology, 

precipitation, and water quality of the LREW have been monitored by the Southeast 

Watershed Research Laboratory (SEWRL) since 1967 (Bosch and others 2007). The climate 

is humid subtropical with a long growing season. Annual precipitation averages 1192 mm 

yr-1. Mean annual temperature is around 18.7°C, with the coldest month of the year being 

January with an average temperature of 10.6°C and the warmest being July with an average 

temperature of 26.8°C.

Streamflow during the months of December through April in watersheds throughout the 

Southeastern Coastal Plain is typically much greater than during the months of May through 

November. Greater precipitation and lower evapotranspiration rates during the winter and 

spring months create higher soil-moisture and greater aquifer recharge, increasing surface 

runoff responses and groundwater contributions to streamflow. Baseflow, the portion of 

streamflow coming from vadose zone and groundwater sources, makes up a large fraction of 

the streamflow during the winter and spring periods. Thus, baseflow is extremely important 

to sustaining streamflow throughout the Southeastern Coastal Plain. Increasing demands on 

groundwater, changes in land-use, and changes in precipitation patterns due to climate change 

are all expected to impact baseflow conditions and streamflow volume.

Historical precipitation and streamflow data were obtained from the SEWRL database 

(Bosch and others 2007). The period of record examined was from 1972 to 2013. This 

analysis was limited to examination of data from the largest watershed, Watershed B, a 334 

km2 drainage area. Daily precipitation and streamflow data extrapolated from the subdaily 

data were examined. Data were partitioned into annual and seasonal periods for hydrograph 

1

David Bosch, Research Hydrologist, USDA Agricultural Research Service, Southeast Watershed Research Lab, Tifton, GA 31794

Randall Williams, Agricultural Engineer, USDA Agricultural Research Service, Southeast Watershed Research Lab, Tifton, GA 31794

Timothy Strickland, Soil Scientist, USDA Agricultural Research Service, Southeast Watershed Research Lab, Tifton, GA 31794

Jeff Arnold, Agricultural Engineer, USDA Agricultural Research Service, Grassland Soil and Water Research Lab, Temple, TX 76502

Peter Allen, Geologist, Baylor University, Waco, TX 76706
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 235

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

analysis. The seasonal periods selected, based upon prior research, were December through 

February (winter), March through May (spring), June through August (summer), and 

September through November (fall). The digital filter method used for separation of high and 

low frequency signals was used for separation of baseflow (Lim and others 2005). The two 

parameter Eckhart digital filter was used with a maximum baseflow index (BFImax) of 0.80 

and an alpha value of 0.98. The baseflow index is the ratio of baseflow to total streamflow.

Examination of the 42 years of annual flow data produced an average baseflow index of 0.54 

(Table 1). Average seasonal baseflow indexes varied from 0.57 for the spring to 0.42 for the 

summer (Table 1). Variability of the annual data was low as were the variability of the winter, 

spring, and summer seasons. Variability of the fall was higher.

Baseflow was found to decrease as a function of increasing rainfall (Fig. 1). This is attributed 

to the saturated conditions which accompany high precipitation, subsequently leading to 

rapid surface runoff. Trends in baseflow were examined for both the annual and seasonal data. 

Annual baseflow was found to be decreasing over the 42 year period. Analysis of precipitation 

data indicated annual precipitation over the 42 year period was also decreasing (α=0.05). 

Since higher annual precipitation appears related to lower baseflow, a decreasing annual 

precipitation would be expected to yield lower baseflow conditions, conflicting observed longterm baseflow trends. Examination of seasonal precipitation patterns indicated decreasing 

long-term trends for the winter and spring precipitation and increasing trends for the summer 

Figure 1—Baseflow index as a function of annual rainfall illustrating a decreasing 

trend in baseflow as a function of increasing annual rainfall (significant at α=0.05).

Table 1—Results of annual and seasonal basefl ow analysis for Little River Station B, 1972-2013.

Period Winter Spring Summer Fall Yearly

Basefl ow Index 0.55 0.57 0.42 0.47 0.54

Standard Deviation 0.07 0.09 0.09 0.13 0.04
236 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

and fall precipitation. This shift in seasonal precipitation patterns would explain the long-term 

decrease in baseflow.

Overall, baseflow was found to produce 54 percent of annual streamflow, 13 percent less 

than prior published results. Baseflow was the largest during the months from December 

through May (55-57 percent) and the least during the months from June through November 

(42-47 percent). Annual baseflow was found to decrease with increasing annual precipitation. 

Data indicated a decreasing long-term trend in annual precipitation, decreasing baseflow, 

and increasing variability. Data also indicate a shift in seasonal precipitation from the winter 

and spring to the summer and fall which is believed to contribute to reduced baseflow in the 

watershed.

LITERATURE CITED

Bosch, D.D.; Sheridan, J.M.; Marshall, L.K. 2007. Precipitation, 

soil moisture, and climate database, Little River 

Experimental Watershed, Georgia, United States. Water 

Resour. Res. 43(9). W09472. doi:10.1029/2006WR005834.

Lim, K.J.; Engel, B.A.; Tang, Z.; Choi, J.; Kim, K-S.; 

Muthukrishnan, S.; Tripathy, D. 2005. Automated web 

GIS based hydrograph analysis tool, WHAT. Journal of the 

American Water Resources Association. 41(6):1407-1416.

Maddox, N. 2013. LTAR: Critical research for sustainable 

intensification of our agroecosystems. Crop Science Society 

of America News. June, 2013. pp. 4-9.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 237

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THIRTY-YEAR RESULTS FROM A PAIRED-CATCHMENT STUDY 

OF UPLAND FLOWPATH RESPONSES TO FOREST COVER 

CONVERSION IN NORTHERN MINNESOTA

Stephen Sebestyen, Randy Kolka1

Long-term studies on paired-research catchments have often showed periods of changes to 

water yields and peak stormflow after forest harvesting. Most studies have focused on wholecatchment or downstream responses. In contrast, few studies have ever been established to 

measure and investigate specific pathways of water routing through catchment soils or how 

sub-catchment hydrological flowpaths respond to experimental vegetation manipulations, as 

well as common metrics of annual water yields and stormflow magnitudes. At the Marcell 

Experimental Forest (MEF) in northern Minnesota, subsurface and surface runoff collectors 

were operated in a paired-catchment study of forest conversion to conifer (spruce/pine) 

cover after clearcutting of deciduous (aspen/birch) trees on upland mineral soils. The runoff 

collectors measured amounts of flow from mineral soils on hillslope plots. Upland runoff data 

were collected from both north- and south-facing slopes in a reference and an experimental 

catchment. In the MEF landscape, which includes northern peatlands, the hillsllope flowpaths 

drain to central peatlands. As such, we distinguish between sources of water in upland and 

peatland soils, as well as apportion flow along the two different upland flowpaths. Herein, we 

report on the timing and magnitude of forest-conversion effects on the routing of water along 

surface and subsurface runoff pathways. Annual water yields increased during the first postharvest decade and returned to pre-harvest levels from 10-20 years after harvest/conversion. 

During the third post-harvest decade, annual water yields continued to decrease and water 

yields were about 50 percent lower relative to the pre-harvest period. Since the upland 

clearcut in 1980, total annual surface and subsurface runoff amounts from the converted forest 

have decreased to a trivial annual amount, while streamflow and upland runoff amounts in 

the reference catchment showed no trends. To elucidate reasons why these changes occurred, 

we initiated a study of transpiration. Together, these studies suggested that forest conversion 

in post-glaciated catchments with northern peatlands may lead to fundamental changes in 

catchment hydrology. The uplands now yield practically no water and the coniferous forest 

transpires most of the available water, which means that runoff from a peatland is the primary 

source of streamflow. These findings have important implications for the management 

of forested landscapes and the practice of restoring conifer cover to forests of northern 

Minnesota, which is the headwater of several major rivers.

1

Stephen Sebestyen, Research Hydrologist, USDA Forest Service, Northern Research Station, Grand Rapids, MN 55744

Randy Kolka, Research Soil Scientist, USDA Forest Service, Northern Research Station, Grand Rapids, MN 55744
238 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

LONG TERM RECORDS PROVIDE INSIGHTS ON THE RELATIVE 

INFLUENCE OF CLIMATE AND FOREST COMMUNITY STRUCTURE ON 

WATER YIELD IN THE SOUTHERN APPALACHIANS

Peter Caldwell, Chelcy Ford Miniat, Steven Brantley, Katherine Elliott, 

Stephanie Laseter, Wayne Swank1

In forested watersheds, changes in climate and forest structure or age can affect water yield; 

yet few long-term observational records from such watersheds exist that allow an assessment 

of these impacts over time. In this study, we used long-term (~80 yrs) observational 

records of climate and water yield in six reference watersheds at the Coweeta Hydrologic 

Laboratory in the southern Appalachian mountains of North Carolina to determine whether 

water yield has changed over time, and examine and attribute the causal mechanisms of 

change. These six reference watersheds are unmanaged with only successional dynamics and 

natural disturbances altering the forest structure since the 1920s. AutoRegressive, Integrated 

Moving-Average (ARIMA) time series modeling revealed significant (p<0.05) decreases in 

annual water yield (Q) and runoff ratio (Q/precipitation (P)) for lower elevation watersheds 

beginning in 1973; but no significant change in P was identified. These results suggest that 

water loss to evapotranspiration (ET) has been increasing since this time. Further, departures 

in cumulative water yield from that expected given data prior to 1973 could not be explained 

by P alone in low elevation watersheds, providing additional evidence of a change in ET. 

A monthly timestep water balance model, WaSSI, along with our long-term climate record, 

was used to estimate the impact of changes in other climatic variables on water yield. This 

approach allowed us to separate the influence of climate from that of changes in forest 

structure and composition. These simulations revealed that changes in water yield in some 

watersheds could not be explained by climate alone, suggesting that vegetation dynamics 

have also contributed to the changes in ET. Lastly, we combined species composition, stem 

diameter and stem density data from long term permanent plot surveys with tree water use 

by species and diameter derived from sap flux measurements. With these data, we estimated 

changes in ecosystem water use that corroborate the changes in ET and Q not explained by 

climate alone for the six reference watersheds. Our results suggest that natural disturbances 

and successional vegetation dynamics can induce significant changes in water yield even in 

unmanaged forested watersheds, a conclusion only made possible because long-term records 

were valued and maintained over 80 years. Our results could have significant implications for 

water supply in the region and may inform forest management strategies to mitigate climate 

change impacts on water resources, as well as emphasize the importance of maintaining long 

term monitoring networks.

1

Peter Caldwell, Research Hydrologist, USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, NC 28763

Chelcy Ford Miniat, Research Project Leader, USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, NC 28763

Steven Brantley, Assistant Scientist, Joseph W. Jones Ecological Research Center, Newton, GA 39870

Katherine Elliott, Research Ecologist, USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, NC 28763

Stephanie Laseter, Hydrologist, USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, NC 28763

Wayne Swank, Scientist Emeritus, USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, NC 28763
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 239

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

1

John Campbell, Research Ecologist, USDA Forest Service, Northern Research Station, Durham, NH 03824 

Matthew Vadeboncoeur, Research Scientist, Earth Systems Research Center, University of New Hampshire, Durham, NH 03824

Heidi Asbjornsen, Associate Professor, Department of Natural Resources, University of New Hampshire, Durham, NH 03824

Mark Green, Associate Professor, Center for the Environment, Plymouth State University, Plymouth, NH 03264 

Mary Beth Adams, Research Soil Scientist, USDA Forest Service, Northern Research Station, Morgantown, WV 26505 

Elizabeth Boyer, Associate Professor, Department of Ecosystem Science and Management, Pennsylvania State University, University Park, PA 16802

EVALUATING BIOLOGICAL AND PHYSICAL DRIVERS OF 

EVAPOTRANSPIRATION TRENDS AT NORTHEASTERN US WATERSHEDS

John L. Campbell, Matthew A. Vadeboncoeur, Heidi Asbjornsen, Mark B. Green, 

Mary Beth Adams, and Elizabeth W. Boyer1

Despite a general consensus that the Earth’s hydrologic cycle is intensifying as a result of 

anthropogenic climate forcing (e.g. Huntington 2006), there remains substantial uncertainty 

over the consequences of this intensification for terrestrial evapotranspiration (ET; e.g., 

Hobbins and others 2004, Walter and others 2004, van Heerwaarden and others 2010). Most 

models indicate that climate change will cause an increase in ET, but evidence from field 

observations has been inconsistent. Unidirectional changes in ET could profoundly alter local 

water balances and streamflow dynamics, having important implications for water supply and 

associated services, including drinking water, irrigation, recreation, wastewater assimilation, 

and power generation. 

We evaluated long-term trends in ET at three small (39 to 123 ha), gauged reference 

watersheds in the northeastern U.S. with the longest combined records of precipitation and 

streamflow: Fernow Experimental Forest, West Virginia (FEF); Hubbard Brook Experimental 

Forest, New Hampshire (HBEF); and Leading Ridge, Pennsylvania (LR). Although these 

measurements are collected at other small watersheds in the region, the selected watersheds 

have records that are 25 to 45 years longer than any other comparable watersheds. We 

estimated ET with the water balance approach (ET=precipitation-streamflow), which assumes 

that changes in groundwater storage are minimal on an annual basis and seepage loss is 

negligible. Long-term trends were evaluated with the Mann-Kendall test, which is a nonparametric test that is commonly applied to analyses of long-term hydrometeorological time 

series data (Helsel and Hirsch 1992). The slope for each trend was calculated as the median of 

all possible pair-wise slopes (Sen 1968). Reported p values were considered significant at the 

α = 0.05 level.

When all the years of available data were considered, time series analyses showed significant 

declines in ET at FEF and HBEF and no significant change at LR (Fig. 1). When a common 

time frame was used (i.e., 1959-2011), the ET trend at FEF remained negative, but was not 

significant (slope=-0.682 mm yr-1, p=0.101). Use of a common time frame had little effect on 

the slope and p-value for HBEF because only one year was eliminated from the analysis (i.e. 

1958). The lack of consistent trends in ET among watersheds suggests that local influences 

may override potential broader regional drivers of ET. In addition to significant declines in 

ET, HBEF also had significant increasing trends in precipitation (slope=5.6 mm yr-1; p=0.002) 

and stream water (slope=6.9 mm yr-1; p=0.001), whereas the other two watersheds showed 

no significant trends. Evapotranspiration at the HBEF differs from the other watersheds, in 

that a smaller fraction of the precipitation entering the watershed is transpired/evaporated (36 

percent) compared to FEF (56 percent) and LR (59 percent). This difference is likely due to 

the longer growing season at the more southerly sites, which provides more opportunity for 

transpiration. 
240 Headwaters to Estuaries: Advances in Watershed Science and Management

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

Hydrometeorological data from each site was used to explore some of the potential underlying 

climatic mechanisms that could explain the variability in ET. Stepwise multiple linear 

regression (backwards elimination) was used to identify the most important climatic factors 

that affect ET. We considered several potential drivers including summer (June, July, August) 

minimum and maximum air temperature, vapor pressure deficit (VPD) at 1400 EDT (www.

ncdc.noaa.gov), Palmer Drought Severity Index (http://www.ncdc.noaa.gov/cag), and annual 

and growing season precipitation. At LR, the only significant term was growing season 

precipitation, which showed a significant positive effect (R2=0.18). At FEF, a more complex 

model explained more of the variability in ET (R2=0.61) with annual precipitation, growing 

season VPD and maximum air temperature showing significant positive effects, and summer 

minimum air temperature showing a negative effect. At HBEF, the best model included only 

summer precipitation, which interestingly, showed a significant negative relationship with 

ET (R2= 0.10) and was counter to our expectations. Including year as a covariate improved 

the model at HBEF (R2=0.16), but had no effect at LR and only slightly improved the model 

at FEF (R2=0.67). The positive relationship between summer precipitation and ET at FEF 

and LR indicates that ET is sometimes limited by water availability at these watersheds. It 

is unclear what is driving the negative relationship between ET and summer precipitation 

at HBEF, but may be related to factors that were not quantified, such as cloudiness or soil 

moisture-temperature interactions. Nevertheless, the negative relationship suggests that water 

availability is not limiting ET at HBEF and that it is more likely limited by energy at this 

cooler site.

To further evaluate controls on ET, we analyzed tree ring chronologies collected from 

5 individuals (3 cores per tree) of three dominant tree species at each of the three study 

watersheds. Ring widths were measured to the nearest 0.01 mm (Velmex Measuring System 

and measureJ2X software) and cross-dated (verified with the COFECHA program, Holmes 

1983). Autoregressive standardization (ARS) was used to convert raw ring-width series 

into growth indices that contain detrended patterns in variation that are representative of 

the stand. Pearson correlation coefficients (Table 1) indicated that ARS chronologies were 

correlated with ET at FEF (except sugar maple) and LR, but not at HBEF. At FEF and LR, 

Figure 1—Long-term trends in evapotranspiration (ET) calculated using the water balance 

approach for gaged watersheds at the Fernow Experimental Forest, West Virginia; 

Hubbard Brook Experimental Forest, New Hampshire; and Leading Ridge, Pennsylvania.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 241

New Insights into Studies on Long Term Experimental Watersheds to Address Contemporary Emerging Issues (Part 3)

trees tended to grow better during wet summers (low VPD, high precipitation, high PDSI), 

and less during warm summers (high max temp, high VPD). These patterns are consistent 

with the hydrometeorological-ET relationships and indicate that water stress plays a role in 

limiting ET at these sites. At HBEF, there were no significant relationships between climate 

variables and ARS chronologies, though notably the relationships were opposite of the other 

two watersheds, trending towards less growth in wet summers, and more growth with higher 

maximum temperatures. 

Future work will involve analyses of carbon (δ13C) and oxygen (δ18O) isotopes in tree rings 

to further elucidate ET patterns. Tree ring δ13C can be used to identify changes in water use 

efficiency, and δ18O assists in determining whether those changes in water use efficiency 

are due to changes in photosynthetic rate (e.g., because of changes in nutrient supplies or 

environmental stressors such as acid deposition) or stomatal conductance (e.g., in response to 

changes in VPD). These advances are providing critical insight into patterns of ET within the 

Northeast region, enabling a better understanding of the relative importance of site-specific 

and regional drivers of ET.

LITERATURE CITED 

Helsel, D.R.; Hirsch, R.M. 1992. Statistical Methods in Water 

Resources. Elsevier Science, Amsterdam. 522 p.

Hobbins, M.T.; Ramirez, J.A.; Brown, T.C. 2004. Trends 

in pan evaporation and actual evapotranspiration across 

the conterminous U.S.:Paradoxical or complementary? 

Geophysical Research Letters. 31, L13504.

Holmes, R.L. 1983. Computer assisted quality control in tree 

ring dating and measurements. Tree-ring Bulletin. 41: 45-53.

Huntington, T.G. 2006. Evidence for intensification of the global 

water cycle: Review and synthesis. Journal of Hydrology. 

319: 83-95.

Sen, P.K. 1968. Estimates of the regression coefficient based 

on Kendall’s tau, Journal of the American Statistical 

Association. 63: 1379-1389.

van Heerwaarden, C.C.; Arellano, J.V.D.; Teuling, A.J. 2010. 

Land-atmosphere coupling explains the link between 

pan evaporation and actual evapotranspiration trends in a 

changing climate. Geophysical Research Letters. 37, L21401.

Walter, M.T.; Wilks, D.S.; Parlange, J.-Y.; Schneider, R.L. 2004. 

Increasing evapotranspiration from the conterminous United 

States. Journal of Hydrometeorology. 5: 405-408.

Table 1—Pearson correlation coeffi cients of ARS tree ring chronologies and climatic variables for watersheds 

at the Fernow Experimental Forest, West Virginia; Hubbard Brook Experimental Forest, New Hampshire; and 

Leading Ridge, Pennsylvania.

ET Temperature Water stress Precipitation

Summer 

Tmin

Summer 

Tmax

Summer 

VPD

Summer 

PDSI Annual Summer

Fernow 

 Sugar maple 0.072 0.046 -0.133 -0.274* 0.086 0.092 0.331*

 Red oak 0.246* 0.146 -0.176 -0.291* 0.403* 0.265* 0.419*

 Tulip poplar 0.307* 0.100 -0.315* -0.282* 0.435* 0.373* 0.311*

Leading Ridge

 Sugar maple 0.332* -0.033 -0.281* -0.451* 0.094 0.215 0.408*

 Red oak 0.367* 0.104 -0.337* -0.243 -0.030 0.310* 0.258

 White pine 0.307* -0.012 -0.300* -0.035 -0.206 0.105 0.172

Hubbard Brook

 Sugar Maple -0.141 -0.082 0.058 0.180 -0.207 -0.116 -0.014

 American Beech -0.125 -0.223 0.040 -0.044 -0.121 -0.249 -0.079

 Red spruce 0.051 -0.021 -0.129 0.220 0.101 -0.095 -0.002

* Indicates statistical signifi cance at the α=0.05 level.

Advances in Evapotranspiration and Modeling 

on Multiple Land Uses
244 Headwaters to Estuaries: Advances in Watershed Science and Management

Advances in Evapotranspiration and Modeling on Multiple Land Uses

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

UNDERSTANDING AND MANAGING THE WATER USE OF 

PLANTED FORESTS IN A CHANGING ENVIRONMENT

Jami Nettles1

Forest productivity will only become more important in the future, not just for carbon 

sequestration and renewable energy but for wood products and economic security for an 

increasing population. However, the threat of increasing drought and resource scarcity 

means a need for more explicit characterization of the water use of planted forests and 

the understanding of productivity trade-offs necessary to reduce water use. This requires 

prediction of species-specific water use under different soil, topographic, climate, and 

planting conditions and a mechanism to account for trade-offs in ecosystem services that 

cannot always be directly compared. High quality site-specific research has been conducted 

and synthesized globally to illustrate general principles: in an energy limited setting, trees 

use more water than grass in a ratio that increases with water availability. Plant physiology 

studies have given an understanding of water use (evapotranspiration (ET)) response to soil 

and atmospheric conditions, somewhat extractable to various tree species. But knowledge 

bridging the scale from landscape to plant for a given site is still limited. Several strategies 

for accounting for and reducing the water use of planted forests have been suggested, 

including fees for additional water consumption over a baseline and site-specific management 

techniques such as thinning, understory suppression, and site layout in the landscape and 

within the management tract; however, there is limited research linking these to operational 

forestry. This presentation uses ET data from silvicultural and biofuel feedstock research and 

industrial ownership patterns in the southeastern US to evaluate proposed water management 

strategies and estimate water yield, productivity, and economic outcomes. New ET assessment 

methods will allow not only scientists, but planners and forest managers the opportunity 

to quantify the water use of plantation forests. Management techniques, however, must be 

developed along with the data. We must not just use an objective function that maximizes 

runoff and favors low productivity settings, but consider the effect of water for ecological 

requirements and forest productivity and develop workable forest management strategies that 

optimize benefits.

1

Research Hydrologist, Weyerhaeuser Company, Columbus, MS 39704 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 245

Advances in Evapotranspiration and Modeling on Multiple Land Uses

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

COMPARATIVE ANALYSES OF MEASURED EVAPOTRANSPIRATION 

FOR VARIOUS LAND SURFACES

Suat Irmak1

There is a significant lack of continuously measured ET data for multiple land surfaces 

in the same area to be able to make comparisons of water use rates of different agroecosystems. This research presentation will provide continuous evapotranspiration and 

other surface energy balance variables measured above multiple land use and management 

practices. The presentation is a part of a large surface energy balance and associated 

variables measurement network [Nebraska Water and Energy Flux Measurement, Modeling, 

and Research Network (NEBFLUX)]. NEBFLUX is a statewide network that is designed 

to measure evapotranspiration, microclimatic and climatic variables, plant physiological 

parameters (yield, biomass production, plant height, leaf area index, leaf stomatal functions, 

leaf temperature, etc.), soil water content (every 0.30 m down to 1.8 m from soil surface on 

an hourly basis throughout the year), and other surface characteristics for various vegetation 

surfaces under different tillage, irrigation and rainfed management settings. It is a network of 

micrometeorological tower sites that mainly uses advanced instrumentation such as Bowen 

ratio energy balance systems (BREBS) and Eddy Covariance System to measure surface water 

and energy fluxes between terrestrial agro-ecosystems and microclimate.Vegetation surfaces 

include center pivot-irrigated maize and soybean rotation under disk-till, no-till, and ridge-till, 

rainfed winter wheat, subsurface drip-irrigated winter wheat, subsurface and center pivotirrigated continuous maize, center pivot-irrigated seed maize/cover crop rotation, irrigated 

continuous soybean;center pivot-irrigated grassland; rainfed grassland; alfalfa, rainfed 

switchgrass, riparian vegetation comprised of Phragmites (Phragmites australis)-dominated 

cottonwood (Populus deltiodes var. occidentalis) and peach-leaf willow (Willow salix) plant 

communities.

1

Harold W. Eberhard Distinguished Professor of Biological Systems Engineering, College of Engineering, University of NebraskaLincoln, Lincoln, NE 68583
246 Headwaters to Estuaries: Advances in Watershed Science and Management

Advances in Evapotranspiration and Modeling on Multiple Land Uses

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

URBAN EVAPOTRANSPIRATION IN A HUMID ENVIRONMENT - 

ORLANDO, FLORIDA, USA

David M. Sumner, Cor M. J. Jacobs1

An areally-integrated assessment of ET flux was obtained using eddy covariance methods 

over an urban/suburban landscape in the humid sub-tropical environment of Orlando, 

Florida, USA. Mean annual ET during the 3.5-year study period was 921 mm. On average, 

ET returned a large fraction of rainfall to the atmosphere (72 percent). But annual rainfall 

varied much more on a year-to-year basis (922 to 1,746 mm) than did urban ET (843 to 974 

mm). Interestingly, 12-month periods of relatively high ET occurred during drier periods and 

12-month periods of relatively low ET occurred during wetter periods. These results may be 

related to the generally drier atmosphere and less cloud cover that occur during lower rainfall 

periods. In addition, this largely urban environment is not subject to large soil moisture 

limitations because of the prevalence of lawn irrigation and lakes. Corroboration of the ET 

measurements was provided by independent water budgets for two watersheds that make up 

much of the source area for the ET measurements. An urban analogue to the “crop coefficient” 

concept was derived for the studied landscape. This metric was combined with an available 

satellite-based, State of Florida reference ET product (http://fl.water.usgs.gov/et/) to provide 

a method for transferring the results of this study to similar landscapes for other time periods 

and geographic areas. The results of this investigation in a humid, sub-tropical urban setting 

are compared and contrasted with urban ET estimates for other environments.

1

David M. Sumner, Associate Director Hydrologic Studies, US Geological Survey, Caribbean-Florida Water Science Center, Lutz, FL 33559

Cor M. J. Jacobs, Researcher on micrometeorology and gas exchange, Wageningen University & Research Centre, Wageningen, Netherlands
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 247

Advances in Evapotranspiration and Modeling on Multiple Land Uses

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

OPERATIONAL ET REMOTE SENSING (RS) PROGRAM FOR IRRIGATION 

SCHEDULING AND MANAGEMENT: CHALLENGES AND OPPORTUNITIES

Prasanna Gowda1

Evapotranspiration (ET) is an essential component of the water balance and a major 

consumptive use of irrigation water and precipitation on cropland. Any attempt to improve 

water use efficiency must be based on reliable estimates of ET for irrigation scheduling 

purposes. In the Texas High Plains, irrigation scheduling is implemented using lysimeterbased crop coefficients and reference ET data from the Texas High Plains ET Network.This 

presentation will discuss the current state of irrigation management in the Texas High Plains, 

knowledge gaps, ongoing developments, and the role of remote sensing based regional ET 

mapping algorithms with respect to irrigated agriculture in the Texas High Plains. Also, 

ongoing multi-institution research effort to enhance ET and irrigation algorithms in crop and 

hydrological models will be highlighted.

1

Prasanna Gowda, Research Leader, USDA Agricultural Research Service, Grazinglands Research Laboratory, El Reno, OK 73036 
248 Headwaters to Estuaries: Advances in Watershed Science and Management

Advances in Evapotranspiration and Modeling on Multiple Land Uses

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ADVANCED IMAGE PROCESSING APPROACH FOR ET ESTIMATION 

WITH REMOTE SENSING DATA OF VARYING SPECTRAL, 

SPATIAL AND TEMPORAL RESOLUTIONS

Sudhanshu Panda, Devendra Amatya, Young Kim, Ge Sun1

Evapotranspiration (ET) is one of the most important hydrologic parameters for vegetation 

growth, carbon sequestration, and other associated biodiversity study and analysis. Plant 

stomatal conductance, leaf area index, canopy temperature, soil moisture, and wind speed 

values generally correlate well with ET. It is difficult to estimate these hydrologic parameters 

of vast forest cover through in-situ measurements. But remote sensing has the proven ability 

for estimating some of those hydrologic and crop growth parameters in a rapid, accurate, and 

cost-effective manner. Since forest land cover may not be always homogeneous it is more 

difficult to use remote sensing products to model these ET related hydrologic parameters. 

The goal of this study is to develop advance image processing approach for developing ET 

parameter estimation model for different cover conditions like homogenous pine, homogenous 

switch grass, pine and understory, pine and switch grass multi-cropping, and unmanaged pine 

forest. The image data produced by different remote sensors on satellite systems have unique 

characteristics- spatial, spectral, radiometric, and temporal. Image spatial resolution varies 

with sensors like Landsat 7/8 (30 m), SPOT MSS (10 m) and Panchromatic (5 m), NAIP 

imagery (1 m) and CIR orthoimageries (0.15 m). Spectral resolution differs with different 

spectral bands, i.e., Landsat 7 ETM+ with 8 bands, Landsat 8 with 11 bands, SPOT with 5 

bands, and aerial sensors with 4 bands. Individual spectral bands has the ability to correctly 

determine (in our case) different ET parameters more efficiently and accurately. Radiometric 

resolution refers to the data depth indicative of the sensitivity of the sensor to incoming 

energy. Temporal resolution refers to the revisit frequency/time of the sensor to a specific 

location on earth surface, e.g., Landsat revisit time is 16 days over a specific geographic 

location on Earth. This helps in our ET parameter study better as the changes in ET 

parameters over time during growth period(s) can be ascertained from remotely sensed Digital 

Number values and modelled. This study encompasses different study sites such as Parker 

Tract, Carteret, and Lenoir, NC, Green County, AL, and Calhoun County, MS with different 

vegetation cover types. The study distinguishes different imagery usage based on their sensor 

characteristics as discussed with scientific deliberations to develop ET and ET parameter 

prediction models of the vegetation types. In the process, advanced image analysis protocols 

are developed for efficient and accurate ET and ET parameter prediction model development.

1

Sudhanshu Panda, Associate Professor, Institute for Environmental & Spatial Analysis, University of North Georgia, Gainesville, GA 30566

Devendra Amatya, Research Hydrologist, Center for Forested Wetland Research, USDA Forest Service, Cordesville, SC 29434

Young Kim, Undergraduate Student, Institute of Environmental Spatial Analysis, University of North Georgia, Gainesville, GA 30566

Ge Sun, Research Hydrologist, USDA Forest Service, Southern Research Station, Raleigh, NC 27606
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 249

Advances in Evapotranspiration and Modeling on Multiple Land Uses

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ESTIMATING WATERSHED EVAPOTRANSPIRATION ACROSS THE 

UNITED STATES USING MULTIPLE METHODS

Ge Sun, Shanlei Sun, Jingfeng Xiao, Peter Caldwell, Devendra Amatya, Suat Irmak, 

Prasanna H. Gowda, Sudhanshu Panda, Steve McNulty, Yang Zhang1

Evapotranspiration (ET) is the largest watershed water balance component only next to 

precipitation in the United States. ET is closely coupled with ecosystem carbon and energy 

fluxes, affects flooding or drought magnitude, and is also a good predictor for biodiversity 

at a regional scale.Thus, accurately estimating ET is of paramount importance to quantify 

the effects of land use change and climate change on watershed ecosystem services in water 

supply, water resources management, carbon sequestration, and biodiversity conservation. 

However, ET remains to be an imprecise science and difficult to quantify at the watershed 

level.This study compared ET estimates for over 400 watersheds with size ranging 40-25751 

km2 using multiple independent methods including watershed water balance (Precipitation 

– Streamflow or P-Q method), eddy covariance net work (AmeriFlux, NEBFLUX) approach 

by up-scaling eddy flux measurement using the regression tree method (EC-MOD), MODIS 

based remote sensing approach, and watershed hydrologic modeling (e.g., WaSSI, SWAT). 

Our preliminary analysis found that there were large discrepancies in the computed watershed 

ET estimates among the selected methods due to different assumptions and limitations among 

the ET methods. In particular, ET estimated by the eddy covariance method or MODIS 

products were 25-40 percent lower than the estimates by the P-Q method. The WaSSI model 

generally over-estimated ET by 20 percent when compared to the P-Q (534±196 vs 487±263 

mm/yr) method.We discuss the potential causes of the discrepancies found in this study and 

methods to improve ET estimates at a watershed scale.

1

Ge Sun, Research Hydrologist, USDA Forest Service, Southern Research Station, Raleigh, NC 27606

Shanlei Sun, Post-Doctoral Researcher, Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695

Jingfeng Xiao, Research Associate Professor, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824

Peter Caldwell, Research Hydrologist, USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, NC 28763

Devendra Amatya, Research Hydrologist, Center for Forested Wetlands Research, USDA Forest Service, Cordesville, SC 29434

Suat Irmak, Harold W. Eberhard Distinguished Professor of Biological Systems Engineering, College of Engineering, University of NebraskaLincoln, Lincoln, NE 68583

Prasanna H. Gowda, Research Leader, USDA Agricultural Research Service, Grazinglands Research Laboratory, El Reno, OK 73036

Sudhanshu Panda, Associate Professor, Institute for Environmental & Spatial Analysis, University of North Georgia, Gainesville, GA 30566

Steve McNulty, Supervisory Ecologist, EFETAC, Southern Research Station, USDA Forest Service, Raleigh, NC 27606

Yang Zhang, Professor, Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh NC 27695

Poster Session
252 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

LONG-TERM TRENDS IN CLIMATE AND HYDROLOGY IN 

AN AGRICULTURAL HEADWATER WATERSHED OF 

CENTRAL PENNSYLVANIA, USA

Ray B. Bryant, Haiming Lu, Kyle R. Elkin, Anthony R. Buda, Amy S. Collick, 

Gordon J. Folmar, and Peter J. Kleinman1

Abstract—Climate change has emerged as a key issue facing agriculture and water resources in the US. Long-term 

(1968-2012) temperature, precipitation and streamflow data from a small (7.3 km2) watershed in east-central Pennsylvania 

was used to examine climatic and hydrologic trends in the context of recent climate change. Annual mean temperatures 

increased 0.38°C per decade, which led to an expansion of the growing season, and increased evapotranspiration (+37.1 

mm per decade). Additionally, mean annual precipitation also increased while the overall change in streamflow decreased. 

In general, the findings suggest some challenges for producers and water resource managers with regards to increased 

rainfall and runoff. However, some changes such as an enhanced growing season can be viewed as a positive effect. 

INTRODUCTION

In the humid northeastern USA, climate change concerns 

revolve around increases in annual and seasonal 

temperatures, changes in seasons and greater variability 

in weather patterns that adversely impact agriculture. 

The length of the growing season in the northeast has 

been increasing in response to the increase in minimum 

temperature throughout the northeast United States. Past 

climate change has also altered precipitation patterns and 

watershed hydrology, especially with regard to extreme 

events (Walsh and others 2014). On an annual basis, the 

total precipitation has risen at a rate of 9 mm per decade 

since 1900. 

To date, much of the research on past climate change on 

agriculture and water resources has focused on a regional 

or national scale assessment (Horton and others 2014, 

Walsh and others 2014). While these assessments are 

important, they tend to average the effects of changing 

conditions over a large spatiotemporal scale and ignore 

specific impacts at local scales. Here, we present a 

holistic, long-term (1968-2012) analysis of climate and 

hydrologic trends (annual, seasonal, monthly and daily), 

in the WE-38 watershed, a long-term intensively 

monitored upland basin in the Appalachian mountain 

region of east-central Pennsylvania. 

SITE

The WE-38 watershed is a 7.3 km2 subcatchment of the 

Mahantango Creek watershed (420 km2) located in the 

Ridge and Valley physiographic region of east-central 

Pennsylvania. The climate of WE-38 is temperate and 

humid, with a mean annual temperature of 10.1°C, 

annual precipitation averaging 1080 mm, and streamflow 

representing about 46 percent of total precipitation 

(Bryant and others 2011). Land use and geology in WE38 ranges from mature forest cover on sandstone ridges 

(350-510 m elevation) to mixed cropland and pasture in 

valleys on shale and siltstone (125-300 m in elevation). 

The upland hillsides and ridges feature residual soils 

derived from sandstones and shales that are well drained 

and possess high infiltration capacities. In contrast, soils 

in the lower landscapes and valley bottoms are typically 

derived from colluvial deposits and are characterized by 

poor drainage, perched water tables, and frequent runoff 

generation by saturation excess (Buda and others 2009, 

Gburek and others 2006).

1

Ray Bryant, Soil Scientist, USDA Agricultural Research Service, Pasture Systems & Watershed Management Research Unit, University Park, PA 16802

Haiming Lu, Hydrologist, Nanjing Hydraulic Research Institute, State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing 210029, China 

Kyle Elkin, Research Chemist, USDA Agricultural Research Service, Pasture Systems & Watershed Management Research Unit, University Park, PA 16802

Anthony Buda, Hydrologist, USDA Agricultural Research Service, Pasture Systems & Watershed Management Research Unit, University Park, PA 16802

Amy Collick, Research Hydrologist, USDA Agricultural Research Service, Pasture Systems & Watershed Management Research Unit, University Park, PA 16802

Gordon Folmar, Hydrologist, USDA Agricultural Research Service, Pasture Systems & Watershed Management Research Unit, University Park, PA 16802

Peter Kleinman, Soil Scientist, USDA Agricultural Research Service, Pasture Systems & Watershed Management Research Unit, University Park, PA 16802
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 253

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PROCEDURES

Precipitation, temperature and streamflow data were 

complied using data sets that included a minimum value 

data point of at least once per day. In all three cases, 

automated data collection systems were installed between 

1996 and 1997 to monitor their respective parameters at 5 

minute intervals. 

For portions of data that were missing, standard data 

augmentation techniques were used to infill occasional 

data gaps that resulted from site damage, equipment 

failure, routine maintenance or extreme events (Buda 

and others 2011a, Buda and others 2011b). To replace 

daily missing values for precipitation, simple averaging 

methods were used (McCuen 1998, Dingman 2002). A 

series of linear regressions using predictive equations 

related several water measuring stations were used to fill 

in missing streamflow data. Data gaps in temperature less 

than 5 hours were replaced by linear interpolation while 

data gaps greater than 5 hours were not replaced. 

In order to relate the data from WE-38, other climatic and 

hydrologic records from other measurement stations in 

the area were examined to determine an understanding of 

longer-term regional trends (i.e. those that extend prior 

to 1968). In total, four stations were used which gave 

temperature, precipitation and stream-flow. Using these 

data, a number of different temperature, precipitation and 

streamflow indices were calculated in order to describe 

how the climate and hydrology of WE-38 changed during 

the 45 year study period. The indices used in the study fell 

into three basic categories: measures of extreme values 

(maxima and minima) and central tendency (means), 

which describe, for example, the maximum or minimum 

daily temperature or the annual mean precipitation; 

threshold tendencies, which tally the number of days 

or identify the specific date when a fixed temperature 

or precipitation threshold is exceeded, for instance, 

growing season or last freezing date; and percentilebased threshold indices, which describe the excellence 

rates (number of days) above or below a certain threshold 

(consecutive days with streamflow less than the 10th 

percentile of the distribution). 

In addition to the indices described above, we also 

sought to assess long-term changes in watershed 

evapotranspiration in WE-38 as inferred by the water 

balance equation. All water balance equations were 

done on a calendar year basis to be consistent with the 

assessment of trends in precipitation and temperature. 

Prior to conducting formal statistical analysis of the longterm trends, all of the climate and hydrologic data, as well 

as the indices derived from these data were organized into 

four temporal scales: daily, monthly, seasonal (summer, 

autumn, growing, etc.) and annual. Additionally, we 

also assessed climatic and hydrologic trends over the 

fixed-length growing (15 April - 15 October) and nongrowing (16 October - 14 April) seasons based on average 

conditions in the region. 

Trends in climate and hydrology for each of the four 

temporal scales discussed above were evaluated using the 

rank-based Mann-Kendall test (Hirsch and others 1982). 

The rate of change for each time series was determined 

using the Theil-Sen slope method (Theil 1950, Sen 1968), 

which calculated the median slope of all possible pairs 

of points in the data set. For graphical representation, 

LOWESS regression lines were plotted, as well as an 

11-yr moving average (Cleveland 1979, Matonse and 

Frei 2013). The Mann-Kendall tests and Theil-Sen slope 

calculations were completed using the water quality 

package in the R software environment, while Origin 

software was used to plot the LOWESS regression lines 

and moving average trends.

RESULTS AND DISCUSSION

Temperature

Temperature patterns in the WE-38 watershed were 

generally consistent with those observed in the 

northeastern US, as well as nationally. Mean temperatures 

in the watershed exhibited significant increasing trends 

at annual, seasonal and monthly time scales from 1978 

to 2012. Annual mean temperatures in WE-38 showed a 

smooth, steadily increasing trend (0.38° C per decade) 

during the 35 year temperature monitoring period 

(fig. 1a). 

The mean minimum temperatures also increased 

throughout the WE-38 watershed from 1978-2012. On 

an annual basis, mean minimum temperatures showed 

a smooth upward trend (0.43°C per decade) during the 

study period (fig. 1b), increasing at a rate faster than that 

of the annual mean temperatures. Increases in the mean 

minimum temperatures were evident for all three-month 

seasons, both growing and non-growing seasons, and 

annually. 

Annual mean maximum temperatures in WE-38 

increased along with annual mean and annual mean 

minimum temperatures, albeit at generally slower 

rates for the time scales of the period studied. Annual 

mean maximum temperatures rose steadily during the 

study period (fig. 1c), increasing at a rate of 0.35°C per 

decade. Significant increases in monthly mean maximum 

temperatures occurred in the months of January, March, 

April and September, and during the spring and autumn 

seasons. All of these months and seasons also had 

significant increases in mean minimum temperatures as 

previously discussed. However, there were no increases in 
254 Headwaters to Estuaries: Advances in Watershed Science and Management

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the mean maximum temperatures in June, July and August 

or in the summer season, all of which did show increases 

in mean minimum temperatures. 

Disproportionate changes in maximum and minimum 

temperatures, as described above, resulted in a general 

declining trend in the diurnal temperature range over the 

extent of the watershed (fig. 1d). Diurnal temperature 

range decreased significantly in June and August as a 

result of increases in mean and minimum temperatures 

in the absence of increases in mean maximum 

temperatures. There was also a significant decrease in 

diurnal air temperature range during the summer season 

and the growing season at rates of -0.37 and -0.20 °C 

per decade, respectively. Notably, diurnal temperatures 

range increased in March and April as a result of greater 

increases in mean maximum temperatures relative to 

mean minimum temperatures. 

Seasonal Changes and Core Indices

Indices of warm weather all increased in duration during 

the 1978 to 2012 study period. The lengths of warm 

season, growing season and summer season increased by 

2.82, 2.83 and 4.00 days per decade, respectively, over 

the study period. The changes however, were not uniform 

over time. On average the summer season extended 

from early June to mid-September, but the start and end 

dates varied by one month. The length of the summer 

season (mean daily temperature over 13°C) increased 

continuously, but at a slightly accelerated rate after 1995 

(fig. 2a). In addition, summer days (annual count of days 

with maximum temperature above 25°C) increased by 

4.17 days per decade and tropical nights (annual count 

of days with minimum temperature greater than 20°C) 

increased 0.83 days per decade. 

Figure 1—Long-term trends for the WE-38 watershed (1978 to 2012) in (a) annual mean temperature; (b) annual 

mean minimum temperature; (c) annual mean maximum temperature; and (d) diurnal temperature range (DTR). 

Solid lines represent LOWESS regression trends and dashed lines indicate 11-year centered moving average 

trends.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 255

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The growing season (number of consecutive days with 

daily mean temperature above 5°C) generally extended 

from mid-April to mid-October but dates ranged by 

three weeks. The length of the growing season increased 

rapidly between 1990 and 2002, but changes prior to and 

after this period were minor (fig. 2b). On average, the late 

March to mid-November warm season (consecutive days 

with mean daily temperature above 0°C) showed a flat 

or slightly decreasing trend prior to 1990, then increased 

steadily (fig. 2c). During the 1978 to 2012 period, the 

warm season began as early as late February and ended as 

late as mid-November. 

In contrast, the duration of the cold weather periods in 

WE-38 trended shorter from 1978-2012. The average 

length of the cold season (consecutive days with daily 

temperatures below -5°C) ranged from starting as early as 

mid-December and ending as late as mid-February. The 

length of the cold season decreased at a fairly uniform rate 

(fig. 2d) of -0.74 days per decade, and the number of frost 

days also decreased at a rate of -3.64 days per decade.

The last freezing date in spring retreated at an average 

rate of -5.5 days per decade and at a uniform rate over 

the study period (fig. 3). Over the same period, the first 

freezing date in autumn occurred later at an average rate 

of 4.00 days per decade, and the rate of increase was 

greater after 1995 (fig. 3).

Precipitation

Total precipitation in WE-38 displayed inter-annual and 

seasonal variability over the 45 year study period. Annual 

total precipitation ranged from 710.3 mm to 1905.4 mm, 

with a mean of 1097.8 mm. Seasonally, total precipitation 

during the growing season (mid-April to mid-October) 

was 34 percent higher than during the non-growing season 

Figure 2—Long-term trends in temperature threshold indices in the WE-38 watershed (1978 to 2012) for (a) 

summer season; (b) growing season; (c) warm season; and (d) cold season. Solid lines represent LOWESS 

regression trends and dashed lines indicate 11-year centered moving average trends.
256 Headwaters to Estuaries: Advances in Watershed Science and Management

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with June being the wettest and February being the driest 

months (Table 1). 

Total precipitation generally increased in the watershed 

with the most significant trends occurring at seasonal and 

monthly time scales. Annual total precipitation increased 

at a rate of 21.89 mm per decade, however, the trend was 

not significant. Monthly total precipitation increased 

significantly in October and January at rates of 8.18 

and 6.71 mm per decade, respectively. Notably, none 

of the four seasons showed significant changes in total 

precipitation. 

Trends in intensity of precipitation at daily (d-1) and 

hourly (h-1) time scales were variable, with significant 

increasing trends mostly during the non-growing season. 

Maximum daily precipitation increased in September 

and January at rates of 3.99 mm d-1 per decade and 2.23 

mm d-1 per decade, respectively. There was a significant 

increasing trend in maximum daily precipitation at a 

rate of 5.30 mm d-1 per decade for the autumn season. 

Maximum daily precipitation in the non-growing season 

also increased at a rate of 2.24 mm d-1 per decade, but 

there was no significant change during the growing 

season. The hourly intensity of precipitation in the nongrowing season increased in December and January at 

rates of 0.61 mm h-1 per decade and 5.27 mm h-1 per 

decade, respectively (Table 1). Seasonal trends showed 

increasing hourly intensities of storm events in autumn, 

winter and spring, but no change in the summer. The 

hourly intensity of precipitation also increased during the 

non-growing season, but not during the growing season.

While the intensity of precipitation events clearly 

increased during the non-growing season, the number of 

days with intense rainfall remained largely unchanged 

during the 1968 to 2012 study period. Moderately heavy 

precipitation events became less frequent compared to 

days and event with heavier precipitation. Furthermore, 

days with trace and light precipitation showed opposing 

Figure 3—Long-term trends in the Julian day for last freezing 

date (LFD, top) and first freezing date (FFD, bottom) for the 

WE-38 watershed (1978 to 2012). Solid lines represent LOWESS 

regression trends and dashed lines indicate 11-year centered 

moving average trends.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 257

Poster Session

trends during the study period with the number of days 

having trace precipitation increased at a rate of 0.354 

days per decade. In contrast, to trace precipitation, the 

number of days having light precipitation (2.5 to 12.7 

mm) decreased at a rate of -0.467 days per decade and the 

percentage of precipitation that fell as light precipitation 

also declined. Light precipitation accounted for about 30 

percent of the total. 

Streamflow

Streamflow in the watershed varied seasonally and 

annually over the 45 year monitoring period (Table 

2). Mean monthly streamflow showed strong seasonal 

variations typical for watersheds in the northeast US, 

with the lowest flows occurring in August (12.40 mm) 

and the highest flows occurring in March (77.83 mm). 

These streamflow variations reflected seasonal patterns in 

temperature and evapotranspiration, which were highest 

in summer and lowest in winter. On an annual basis, 

streamflow depth averaged 509.2 mm (46 percent of 

annual precipitation) from 1968 to 2012, with inter-annual 

variability largely driven by annual precipitation. The 

lowest streamflow depth occurred in 2001 (207.4 mm), 

which was the drought of the study period. In contrast, 

2011 saw the highest stream flow depth (1199.9 mm), 

which coincided with the wettest year in the study. 

Total streamflow depth in WE-38 largely declined over 

the 45 year period (Table 2), with most of the significant 

reductions occurring at monthly and seasonal time scales. 

Annual total streamflow depth decreased by -16.9 mm per 

decade, although the trend was not statistically significant. 

On a monthly basis, streamflow depth decreased most 

strongly during the month of February (-7.49 mm per 

decade). Significant decreases in streamflow depth also 

occurred in July and during the summer season at rates of 

-1.24 mm and -5.12 mm per decade respectively. Notably, 

streamflow depth increased markedly in October at a rate 

of 4.95 mm per decade, reflecting the strong increase in 

monthly total precipitation observed. 

Of the 45 year study period, 30 years had flood events 

with peak streamflow exceeding the 2.33 year return 

period. Each of these 30 flood events was either caused 

by a precipitation event that also exceeded the 2.33 year 

Period

Mean precip., mm Total precip., mm PM1d, mm d-1 PM1h, mm hr-1

slope p-value slope p-value slope p-value

Spring

Mar 83.13 2.3 0.27 -0.01 0.44 -0.08 0.3

Apr 87.85 3.99 0.2 0.87 0.32 0 0.47

May 104.46 1.48 0.33 -0.34 0.33 0.87 0.18

Summer

Jun 122.64 -9.49 0.23 -0.79 0.33 -0.34 0.37

Jul 97.94 1.46 0.36 0.55 0.35 0.69 0.23

Aug 98.08 5.52 0.22 -0.3 0.41 -0.7 0.17

Fall

Sep 118.83 6.35 0.19 3.99 0.04 0.83 0.19

Oct 90.48 8.18 0.05 1.35 0.19 0 0.38

Nov 86.45 -4.23 0.11 -0.14 0.44 0.29 0.23

Winter

Dec 78.49 2.61 0.28 0.32 0.41 0.61 0.04

Jan 70.91 6.71 0.08 2.23 0.04 5.27 0.07

Feb 58.07 -0.61 0.42 -0.29 0.37 -0.06 0.26

Spring 275.45 4.31 0.31 0.21 0.36 1.23 0.07

Summer 317.68 -0.32 0.48 0 0.47 -0.39 0.38

Fall 297.64 7.49 0.21 5.3 0.01 1.35 0.09

Winter 208.5 4.22 0.31 0.15 0.11 0.62 0.01

Average growing season 629.11 5.2 0.4 0.7 0.37 0 0.48

Average non-growing season 470.51 2.52 0.42 2.24 0.07 0.79 0.03

Annual 1097.79 21.89 0.14 1.99 0.11 1.03 0.21

Table 1—Trends in precipitation at various temporal scales in the WE-38 watershed (1968-2012). Slopes are 

expressed as a rate of change per decade. Slopes in red show trends with statistical significance at p<0.1.
258 Headwaters to Estuaries: Advances in Watershed Science and Management

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return period, or a rain-on-snow event. Notably, one of the 

largest floods in WE-38 occurred on January 19, 1996, 

and was due to rapid snowmelt induced by heavy rain. 

However, there does not appear to be any trend associated 

with the number of flood events that occur in the warm 

season and are not affected by snowmelt. Furthermore, 

the number of flood events that occur during the cold 

season when runoff is affected by snowmelt appears to be 

declining. 

In WE-38, the average length of periods of low 

streamflow, represented by the maximum consecutive 

days during which mean streamflow was lower than the 

10th percentile, was 16 days and ranged from 0 to 70 days 

(fig. 4). These low streamflow periods increased at an 

average rate of 1.9 days per decade over the study period. 

Annual evapotranspiration strongly increased in the 

watershed at a rate of 37 mm per decade (fig. 5). 

CONCLUSIONS

The implications of climate change trends for agricultural 

production in WE-38 can be viewed as a net positive for 

the kind of row crop agriculture that is typical for the 

study area, at least in the near term. Warmer temperatures, 

driven primarily by increasing minimum temperatures, 

lead to longer growing seasons and more growing degree 

days. While warmer annual mean temperatures will result 

in greater evapotranspiration, monthly precipitation totals 

are also increasing, except for the wettest month of June. 

Decreases in light precipitation events are welcome as 

they are less effective at supplying crop needs and with 

the total increase in precipitation, should be interpreted as 

an increase in more effective precipitation. Significantly 

wetter Octobers may complicate harvests, but the trend 

of the arrival of the first autumn freeze to occur later 

should mitigate this complication. The increase in intense 

Period

Mean Streamfl ow depth

streamfl ow depth Slope p-value

mm mm

Spring

Mar 77.83 -0.45 0.48

Apr 62.69 -1.94 0.34

May 47.26 -3.68 0.11

Summer

Jun 34.92 -1.86 0.16

Jul 14.19 -1.24 0.06

Aug 12.4 -0.74 0.17

Fall

Sep 28.32 -0.25 0.43

Oct 30.84 4.95 0.01

Nov 39.1 -0.23 0.5

Winter

Dec 56.49 1.78 0.3

Jan 53.79 2.29 0.3

Feb 52.34 -7.49 0.02

Spring 187.78 -8.24 0.21

Summer 61.49 -5.12 0.08

Fall 97.56 3.44 0.28

Winter 163.44 -8.01 0.24

Average growing season 178.38 -11.19 0.08

Average non-growing season 332.54 -5.54 0.22

Annual 509.2 -16.9 0.28

Table 2—Trends in streamflow depth in the WE-38 watershed (1968 to 2012). 

Slopes are expressed as a rate of change per decade. Slopes in red show trends 

with statistical significance at p<0.1.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 259

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Figure 5—Long-term trends in annual actual evapotranspiration for 

the WE-38 watershed (1968 to 2012). Solid lines represent LOWESS 

regression trends and dashed lines indicate 11-year centered moving 

average trends.

Annual maximum consecutive days in which 

mean daily streamflow lower than 10th percentile (d)

Figure 4—Long-term trends in the maximum annual consecutive number 

of days during which daily mean streamflow in the WE-38 watershed was 

lower than the 10th percentile (1968 to 2012). Solid lines represent LOWESS 

regression trends and dashed lines indicate 11-year centered moving 

average trends. 
260 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

precipitation events is indicative of a greater risk of crop 

damage, but is of limited geographical extent. However, 

the need for cost of crop insurance may become greater in 

response to this trend. 

With respect to the conservation of the Chesapeake Bay, 

nutrients and sediment are the major pollutants that 

derive from agricultural watersheds in the Susquehanna 

River Watershed. Under current Pennsylvania regulations 

winter spreading of manure is allowed, but producers 

are discouraged against this. However, the decreasing 

snow accumulation that is being seen offer increased 

opportunities to spread manure during low runoff 

risk times. 

In conclusion, the present and near term effects of 

climate change do not appear to present great challenges 

for agricultural production, water resources or the 

Chesapeake Bay conservation efforts, but that does not 

mean that the effects of these changes will not worsen 

in the future. Additionally, the rate of change generally 

appears to be much greater than what has been observed 

in other studies of other geographical areas, and it appears 

to be increasing. Whereas that rate of change is not 

expected to reverse itself, the potentially negative, longer 

term effects of climate change will be realized sooner. 

ACKNOWLEDGMENTS

This study is a contribution from the USDA-ARS 

Pasture Systems and Watershed Management Research 

Unit with collaboration and financial support from the 

USDA-NRCS. Financial support was also granted by the 

China Scholarship Council, Nanjing Hydraulic Research 

institute (NHRI), and the China Special Fund for Water 

Resources Research in the Public Interest (201201026).

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Proceedings of the Fifth Interagency Conference on Research in the Watersheds 261

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Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE WALNUT GULCH LTAR

Phillip Heilman, Susan Moran, Mark Nearing, Mary Nichols, 

Russ Scott, David Goodrich1

The Walnut Gulch LTAR builds on and advances 60 years of research on the USDA-ARS 

Walnut Gulch Experimental Watershed surrounding the town of Tombstone in southeast Arizona. 

Instrumentation on the watershed was initiated in 1953 and currently approximately 149 square 

kilometers of semiarid rangeland are monitored and serve as an outdoor laboratory. The watershed 

is a tributary to the upper San Pedro Basin that drains northward spanning the Mexico-U.S. border. 

Satellite watersheds associated with the WG-LTAR include 8 small watersheds located in the 

Santa Rita Experimental Range (SRER) operated by the Univ. of Arizona that are located roughly 

75 km WNW of Tombstone and 40 km south of Tucson. These watersheds are representative 

of approximately 60 million hectares of brush and grass covered rangeland found throughout 

the semi-arid Southwest in the transition zone between the Chihuahuan and Sonoran Deserts. 

Elevation of the watersheds ranges from ~900 m to 1585 m MSL. In this region, cattle grazing is 

the primary land use with mining, limited urbanization, and recreation making up the remaining 

uses. All the instrumented watersheds are drained by ephemeral channels that are dry about 99 

percentof the time. The “Business as Usual” agricultural practice consists of continuous and 

rotational pasture grazing. Brush management is a relatively common practice to increase forage 

production, improve vegetative cover, and reduce surface soil erosion. It has increased in recent 

years in Texas through New Mexico and into southeastern Arizona due the availability of Natural 

Resource Conservation Service Environmental Quality Incentive Program (EQIP) funding. The 

8 WG-LTAR Santa Rita watersheds have a 40-year set of baseline observations of rainfall, runoff 

and sediment delivery comparing the two different grazing practices with and without mesquite 

(Prosopis velutina). Our proposed alternatively managed production system (AM) will involve 

removing mesquite on two of the Santa Rita watersheds to evaluate the impacts on a number of 

ecosystem services compared with the prior record and the other six untreated watersheds. An 

overview of key historical research results as well as the existing and planned infrastructure and 

experimental design will be presented in this poster.

1

Phillip Heilman, Hydrologist, USDA Agricultural Research Service Watershed Research Center, Tucson, AZ 85719

Susan Moran, Hydrologist, USDA Agricultural Research Service Watershed Research Center, Tucson, AZ 85719

Mark Nearing, Agricultural Engineer, USDA Agricultural Research Service Watershed Research Center, Tucson, AZ 85719

Mary Nichols, Hydraulic Engineer, USDA Agricultural Research Service Watershed Research Center, Tucson, AZ 85719

Russ Scott, Hydrologist, USDA Agricultural Research Service Watershed Research Center, Tucson, AZ 85719

David Goodrich, Hydraulic Engineer, USDA Agricultural Research Service Watershed Research Center, Tucson, AZ 85719
262 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

LONG TERM AGROECOSYSTEM RESEARCH IN THE SOUTHERN PLAINS 

 Jean L. Steiner, Patrick J. Starks, Jurgen Garbrecht, Daniel Moriasi, Paul 

Bartholomew, Jim Neel, Kenneth E. Turner, and Brian Northup1

The Southern Plains (SP) site of the Long Term Agroecosystem Research (LTAR) network 

is headquartered at the USDA-ARS Grazinglands Research Laboratory (GRL) in El Reno, 

Oklahoma. The GRL was established in 1948. A long-term watershed and climate research 

program was established in the Little Washita River Experimental Watershed (LWREW) in 1961 

and in the Fort Cobb Reservoir Experimental Watershed (FCREW) in 2004 (Steiner and others 

2014). The GRL mission is to develop technologies, management strategies, and tools to evaluate 

and manage risks and tradeoffs for integrated crop, forage, and livestock systems under variable 

climate, energy and market conditions. 

Research is conducted at: 1) the 27 km2 GRL which is comprised of tall grass prairie, pastures, and 

annual crops and forages that support beef cattle herds, 2) the 610 km2 LWREW watershed which 

was established to study hydrologic impacts of USDA-funded flood retarding structures, and 3) 

the 786 km2 FCREW watershed that was established to quantify interactive effects of climate, land 

use, and agricultural conservation practices on environmental outcomes. The climate is continental 

with about 210 days in the growing season. Mean annual temperature is 15.5 oC and mean annual 

precipitation is about 850 mm with a gradient across the region. The research sites are within the 

Southern Plains NEON domain; Red-Arkansas HUC 11 watershed; Prairie Gateway farm resource 

region. Climate variability and gradients characterize the Great Plains and are a primary driver of 

agro-ecosystem processes in the region (Garbrecht and others 2014). 

The SP LTAR addresses a spectrum of cropland, pastureland, and grazed prairie characteristic 

of SP landscapes. Extreme climate variability in space and time make it essential to identify 

sustainable and resilient forage-based production systems that are adaptable across enterprise 

types. Developing knowledge and tools to support diverse agricultural systems in the face of 

complex interactive ecological, climate, policy, and economics drivers requires transdisciplinary 

science conducted over decades to provide understanding that is scalable in time and space. 

Anticipated outcomes include production systems that support vibrant rural economies, promote 

biological diversity (soil, plant, and animal), and reduce greenhouse gas emissions, with positive 

impacts on carbon sequestration, water and air quality, and agricultural sustainability. 

Research is affiliated with four of the USDA-ARS National Programs: Water Availability and 

Watershed Management; Forage, Pasture, and Rangeland Systems, Food Animal Production; and 

Global Change, Emissions, and Soils. Major collaborations (Table 1) include the Grazing CAP 

coalition: Oklahoma State University, Kansas State University, University of Oklahoma, Tarleton 

State University, The Samuel Roberts Noble Foundation, and USDA-ARS-Bushland, supported by 

USDA-NIFA-AFRI. The long-term watershed research includes numerous key partners, including 

Oklahoma State University, the Oklahoma Mesonet, Oklahoma Water Resources Board (OWRB), 

1

Jean L. Steiner, Soil Scientist, USDA Agricultural Research Service, El Reno, OK 73036

Patrick J. Starks, Soil Scientist, USDA Agricultural Research Service, El Reno, OK 73036

Jurgen Garbrecht, Hydrologic Engineer, USDA Agricultural Research Service, El Reno, OK 73036

Daniel Moriasi, Hydrologist, USDA Agricultural Research Service, El Reno, OK 73036

Paul Bartholomew, Agronomist, USDA Agricultural Research Service, El Reno, OK 73036 

Jim Neel, Animal Scientist, USDA Agricultural Research Service, El Reno, OK 73036

Kenneth E. Turner, Animal Scientist, USDA Agricultural Research Service, El Reno, OK 73036

Brian Northup, Ecologist, USDA Agricultural Research Service, El Reno, OK 73036
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 263

Poster Session

Oklahoma State University

University of Oklahoma

Oklahoma Mesonet

Grazing CAP

Southern Plains Climate Hub

Kansas State University

South Central Climate Science Center

RISA-SCIPP

Langston University

Tarleton State University - TIAER

Samuel Roberts Noble Foundation 

Oklahoma Conservation Commission

Oklahoma Water Resources Board

USGS

USDA-NRCS, other federal agencies

Numerous ARS locations 

Numerous international universities

Table 1—Key Partners and Collaborators of the Southern Plains LTAR

Figure 1—Schematic of the LTAR-SP research. 
264 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

USGS, Oklahoma Conservation Commission, USDA-NRCS, EPA, US Bureau of Reclamation, 

and landholders in the watershed. Many other aspects of the research involve partnerships with 

additional universities, including Texas AgriLife, University of Oklahoma, Beijing Normal 

University, Universidad Autónoma de Zacatecas, Jomo Kenyatta University, DOI South Central 

Climate Science Center, International Center for Agroforestry.

The broad research emphasis spans productivity and resilience of forage-grazing systems, multiple 

marketing options, agro-ecosystem impacts of climate variability and change at multiple scales, 

and environmental impacts of conservation practices (fig. 1). All of these issues are of global 

relevance. Improved understanding within this regional research program will be linked with other 

long-term research efforts to advance our understanding of processes that transcend regions. 

ACKNOWLEDGMENTS

This work is supported in part by USDA to Project No. 

2012-02355 through the National Institute for Food and 

Agriculture’s Agriculture and Food Research Initiative, 

Regional Approaches for Adaptation to and Mitigation of 

Climate Variability and Change. The project, “Resilience 

and Vulnerability of Beef Cattle Production in the 

Southern Great Plains under Changing Climate Land Use 

and Markets (Grazing CAP)”, is a regional, integrated 

project comprising six institutions including Oklahoma 

State University, Kansas State University, Oklahoma 

University, Tarleton State University, the Samuel Roberts 

Noble Foundation, and USDA-ARS laboratories at El 

Reno, Oklahoma and Bushland, Texas. Project Web site: 

greatplainsgrazing.org. 

LITERATURE CITED 

Garbrecht, J.D.; Zhang, X.C.; Steiner, J.L. 2014. Climate change 

and observed climate trends in the Fort Cobb Experimental 

Watershed, Oklahoma. Journal of Environmental Quality. 

43:1319-1327.

Steiner, J.L.; Starks, P.J.; Garbrecht, J.G.; [and others]. 2014. 

Long-term environmental research: The Upper Washita 

River experimental watersheds, Oklahoma, USA. Journal of 

Environmental Quality. 43:1227-1238.

Steiner, J.L.; Engle, D.M.; Xiao, X. [and others]. 2014. 

Knowledge and tools to enhance resilience of beef grazing 

systems for sustainable animal protein production. Annals of 

the New York Academy of Sciences. 1328: 10–17.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 265

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

GULF ATLANTIC COASTAL PLAIN LONG TERM 

AGROECOSYSTEM RESEARCH SITE, TIFTON, GA

Timothy Strickland, David D. Bosch, Dinku M. Endale, Thomas L. Potter1

The Gulf-Atlantic Coastal Plain (GACP) physiographic region is an important agricultural 

production area within the southeastern U.S. that extends from Delaware in the Northeast to 

the Gulf Coast of Texas. The region consists mainly of low-elevation flat to rolling terrain with 

numerous streams, abundant rainfall, a complex coastline, and many wetlands. The GACP Long 

Term Agroecosystem Research (LTAR) site is representative of the Tifton-Vidalia Upland (TVU) 

physiographic subprovince which has relatively homogeneous geology, soils, parent materials, 

land use, agricultural management, and economic and social patterns. Total row crop land in the 

TVU is about 18 percent of the land area. The remaining land in farms is primarily in woodland 

or pastureland. The 65 percent of the TVU that is not in farms is primarily privately owned 

forest land with about 5 percent of the TVU in urban, suburban, rural housing, or transportation 

uses. Research efforts at the GACP LTAR encompass broad subject areas that are critical to 

agricultural systems in the Southeastern Coastal Plain and are designed to develop ecologicallybased, whole-farm and area-wide approaches that rely on the inherent strengths of our agricultural 

production systems. Principal crops in descending order of acreage are cotton, peanut, corn, 

soybean, and wheat. GACP LTAR sustainable scenario development is focused on sustainable 

intensification of crop production in the face of increased water demand, periodic drought cycles, 

heavy pest and weed pressure, and expectations of increased biofuel feedstock production in the 

Southeastern U.S.

1

Timothy Strickland, Soil Scientist, USDA Agricultural Research Service, Southeast Watershed Research Laboratory, Tifton, GA 31794

David D. Bosch, Hydraulic Engineer, USDA Agricultural Research Service, Southeast Watershed Research Laboratory, Tifton, GA 31794

Dinku M. Endale, Agricultural Engineer, USDA Agricultural Research Service, Southeast Watershed Research Laboratory, Tifton, GA 31794

Thomas L. Potter, Chemist, USDA Agricultural Research Service, Southeast Watershed Research Laboratory, Tifton, GA 31794
266 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

REYNOLDS CREEK LONG-TERM AGRICULTURAL RESEARCH

Mark Seyfried, Fred Pierson, Tony Svjecar, Kathleen Lohse1

The Reynolds Creek Experimental Watershed (RCEW) was established by the Agricultural 

Research Service (ARS) in 1960 to investigate rangeland hydrology issues in the northwestern 

USA. The site, which is administered by the Northwest Watershed Research Center (NWRC) 

in Boise, Idaho, is representative of much of the region, with a 1000 m elevation range and 

associated climate and vegetation range. Precipitation is mostly rain at low elevations and 

averages about 250 mm per y and is mostly snow at higher elevations averaging about 900 mm 

per y. Hydrometeorological and stream flow data collection started shortly after 1960 and the 

network has been expanded to include 8 weirs and 30 meteorological sites. In addition, detailed 

snow and soil water and temperature data are part of the network. Data have been available over 

the internet via ftp since 2000.These data have been used to document climate trends over the 

past 50 years and its impacts on stream flow and soil water dynamics with estimated effects on 

vegetation production. In addition, these data have been part of a major model development 

and testing program, and NWRC snow and soil models are in widespread use. The watershed 

has also been the site of a number of experimental studies investigating management effects, 

especially due to prescribed fire, on overland flow and erosion. Current emphasis is on linking 

hydrological expertise from the ARS with biogeochemical and ecological research based at 

Idaho State University and Boise State University. The RCEW has been designated a Critical 

Zone Observatory (National Science Foundation) and is related, along with ARS unit in Burns, 

Oregon (Range and Meadow Forage Management Research Unit), as part of a new Long Term 

Agricultural Research (LTAR) site. These are separate projects with overlapping objectives. 

The primary objectives of the CZO are to: (i) measure carbon and water fluxes in a variety of 

vegetation and climatic conditions, (this includes net flux using eddy covariance as well as 

individual components of the carbon balance such as forage production), (ii) quantify the spatial 

distribution of soil and vegetative carbon across the entire landscape using a combination of 

soil mapping and verified remote sensing, and (iii) simulate water and carbon fluxes and plant 

production across the landscape using models verified models. For the LTAR, data collection is 

similar with the emphasis on the long-term effects of vegetation change. Work will extend beyond 

the RCEW to relatively degraded, slightly drier location north of the RCEW.

1

Mark Seyfried, Soil Scientist, USDA Agricultural Research Service, Boise, ID 83712

Fred Pierson, Research Leader, USDA Agricultural Research Service, Boise, ID 83712

Tony Svjecar, Research Leader, USDA Agricultural Research Service, Burns, OR 97720

Kathleen Lohse, Associate Professor of Soil and Watershed Biogeochemistry, Idaho State University, Pocatello, ID 83209
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 267

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

AN INTERACTIVE TOOL FOR PROCESSING SAP FLUX DATA 

FROM THERMAL DISSIPATION PROBES

A. Christopher Oishi, Chelcy F. Miniat1

Sap flux sensors are an important tool for estimating tree-level transpiration in forested and urban 

ecosystems around the world. Thermal dissipation (TD) or Granier-type sap flux probes are among 

the most commonly used due to their reliability, simplicity, and low cost. However, the accuracy 

of TD sensors depends upon the correct processing of the raw data. Improper signal processing 

can lead to over- or under-estimation of sap flux and may ignore the contribution of nocturnal 

water through the trunk. In an effort to improve and standardize the approach of TD probe data 

processing, we developed a MATLAB-based software script that combines automated signal 

processing with an interactive QA/QC interface. We show results from a variety of tree species and 

climates.  

1

A. Christopher Oishi, Research Ecologist, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763

Chelcy F. Miniat, Research Project Leader, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763
268 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE CONEWAGO CREEK INITIATIVE: A MODEL FOR COMMUNITY 

WATERSHED ENGAGEMENT AND RESTORATION

Matt Royer, Kristen Kyler, Jennifer Fetter1

Over the last several years, a partnership of over thirty organizations called the Conewago Creek 

Initiative has been working cooperatively in a small watershed to increase community engagement 

and work with farmers and landowners to adopt land management practices to improve water 

quality. The partnership is facilitated by the Penn State Agriculture and Environment Center, a 

research, extension and engagement center of the College of Agricultural Sciences. The concept of 

the Initiative is to establish a “shared discovery” watershed where the value of community based 

private/public partnerships to address nonpoint source pollution challenges can be demonstrated. 

The Initiative was supported by a grant from the National Fish and Wildlife Foundation. Further 

support was provided by the U.S. Department of Agriculture’s designation of the Conewago as 

a Chesapeake Bay “Showcase Watershed” and the Pennsylvania Department of Environmental 

Protection through the Section 319 nonpoint source pollution control program. The Initiative’s 

work has resulted in increased citizen engagement and outreach, an increase in adoption of best 

management practices, and positive water quality improvement trends in the watershed. The 

Initiative provides a model for local watershed community based engagement. It demonstrates 

a preferred approach to address local, upstream water quality problems in order to meet priority 

restoration goals for larger estuarine water bodies, (i.e., the Chesapeake Bay). 

1

Matt Royer, Director, Penn State Agriculture and Environment Center, University Park, PA 16802

Kristen Kyler, Project Coordinator, Penn State Agriculture and Environment Center, University Park, PA 16802

Jennifer Fetter, Watershed Educator, Penn State Extension, Dauphin, PA 17018 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 269

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

CONEWAGO STREAM TEAMS – INCLUDING YOUTH IN 

WATERSHED RESTORATION CREATES LOCAL WATERSHED 

CONNECTIONS, PROMPTS COMMUNITY SERVICE, 

AND INCREASES WATER LITERACY IN YOUTH

Jennifer Fetter, Sanford Smith, Matt Royer1

Youth in Pennsylvania’s Dauphin, Lebanon, and Lancaster Counties were invited to be part of a 

unique opportunity: a chance to learn, hands-on, about the water in their own community and how 

their daily lives impact that water. This is the mission of the 4-H Stream Teams program, which 

was piloted within the Conewago Creek Watershed and surrounding communities in 2010-2013. 

This small, 53 square mile watershed is the focus of much attention, as partners from a widevariety of government agencies, universities, and non-government organizations come together to 

see what a fully collaborative effort (in this case the Conewago Creek Collaborative Conservation 

Initiative) can do to restore a small watershed and ultimately improve the quality of water entering 

the Chesapeake Bay. Thanks to the efforts of Penn State Extension Educators and to funding from 

a USDA-NIFA Integrated Water Quality Program Grant, youth had the opportunity to be included 

in this collaborative effort. The three major components of the 4-H Stream Team concept are 1) 

provide a hands-on water-education curriculum that teaches youth about water conservation, water 

science, and water quality issues 2) focus youth learning experiences on small watersheds where 

their daily lives have the greatest impact and 3) promote community service and outreach projects 

that youth take ownership of in their own small watersheds. With the help of 159 dedicated 

volunteers, over 3,340 youth have been reached through 4-H Stream Team activities. For those 

youth who completed 4-H Stream Teams activities and participated in evaluations, there has 

been demonstrated knowledge gained in water topics, increased knowledge of youth’s own local 

watershed boundaries, and participation in community service and outreach projects that directly 

benefited the local watersheds in and around the Conewago Creek pilot program.

1

Jennifer Fetter, Watershed Educator, Penn State Extension, Dauphin, PA 17018 

Sanford Smith, Extension Specialist, Penn State Extension, University Park, PA 16802 

Matt Royer, Director, Penn State Agriculture and Environment Center, University Park, PA 16802
270 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

CHANGES IN SEDIMENT YIELD AND STREAM MORPHOLOGY IN AN 

ACTIVELY MANAGED FORESTED WATERSHED 

DUE TO UPSTREAM DISTURBANCES

Ilkim Cavus, Latif Kalin, Ferhat Kara1

Attaining high quality water has always been a big concern for humankind. Forested watersheds 

are known to provide the cleanest form of water. However, conversion of forested lands to 

agricultural and/or urban use, as well as disturbances created in forested watersheds lead to 

degradation and deterioration of our water resources. To minimize the disturbance impacts on 

water quality various best management practices (BMPs) such as streamside management zones 

(SMZs) are implemented in managed forested watersheds. On the contrary, any upstream urban 

and agricultural activities where BMPs are not present or are inadequate can negatively impact 

downstream water quality regardless of the presence of downstream BMPs. In a recent study 

two small paired watersheds located near Auburn, Alabama were examined for streamflow 

and sediment yield in 2009 and 2010 to evaluate the efficacy of SMZs at trapping sediment 

yield from a clearcut area. Recent urban activities upstream of the study watersheds and poorly 

designed BMPs around these activities provided us an opportunity to observe and document 

the impacts of upstream disturbances on downstream stream water quality and morphology. Six 

monitoring stations were established to observe flow and sediment yield. Sediment data collection 

began in January 2014, and will proceed until June 2015. In addition to sediment concentration 

measurements, cross-sections of the channels have also being surveyed at several locations across 

the streams, following each significant storm events in order to assess the effects on channel 

morphology. Although a full spectrum of data are not ready to reach to an overarching conclusion, 

data collected so far show substantial increase in sediment load. Sediment concentrations are up 

to two orders of magnitude higher compared to the levels from the previous study where sediment 

concentrations were monitored following a clearcutting. Furthermore, channel morphology is 

altered visibly following almost every significant rain event (>1 inch). Preliminary data suggest 

that assessment of watersheds as a whole is needed in order to define the origin of problems and 

mitigate them more effectively.

1

Ilkim Cavus, Graduate Student, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL 36849

Latif Kalin, Associate Professor, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL 36849

Ferhat Kara, Graduate Student, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL 36849 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 271

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

REAL TIME MONITORING OF NITROGEN, CARBON, 

AND SUSPENDED SEDIMENT FLUX IN TWO SUBBASINS 

OF THE CHOPTANK RIVER WATERSHED

Gregory McCarty, Megan Lang1

Intensive water quality monitoring of agricultural watersheds can provide important information 

on the effects of land cover and effectiveness of conservation practices designed to mitigate water 

quality concerns associated with agricultural production. For this study, robust water quality 

monitoring systems designed to measure nitrate, organic carbon and sediment concentrations using 

in situ UV-Vis spectrometer probes were deployed in two tributaries of the Choptank Watershed, 

Maryland. For accurate flux measurements, each monitoring system was co-located at USGS gage 

stations (USGS 01491000 and 01491500) defining what we have termed as the Greensboro and 

Tuckahoe sub-basins, respectively, within the headwater region of the Choptank River Watershed. 

These sub-basins have similar amounts of cropland but Greensboro has considerably more wetland 

area and greater percentage of cropland on hydric soil. Comparison of nitrate and carbon fluxes 

from these sub-basins will improve understanding of current and historical wetland function in 

agricultural landscapes and impacts of wetland drainage and restoration on nutrient export from 

watersheds. We hypothesize that carbon fluxes provide good indication of wetland connectivity to 

the stream network and can thereby provide information on important ecosystem services provided 

by wetlands within agricultural settings.   

1

Gregory McCarty, Soil Scientist, USDA Agricultural Research Service, Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705

Megan Lang, Visiting Scientist, USDA Agricultural Research Service, Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705
272 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ALBEMARLE SOUND DEMONSTRATION STUDY OF THE 

NATIONAL MONITORING NETWORK FOR U.S. COASTAL WATERS 

AND THEIR TRIBUTARIES

Michelle Moorman, Sharon Fitzgerald, Keith Loftin, and Elizabeth Fensin1

The U.S. Geological Survey’s (USGS) is implementing a demonstration project in the Albemarle 

Sound for the National Monitoring Network for U.S. coastal waters and their tributaries. The goal 

of the National Monitoring Network is to provide information about the health of our oceans and 

coastal ecosystems and inland influences on coastal waters for improved resource management. 

The network integrates biological, chemical, and physical features and links uplands to the coastal 

ocean. The purpose of the Albemarle Sound pilot study is to: 1) Inventory current monitoring 

programs in the Albemarle Sound, 2) Conduct a gap analysis to determine current monitoring 

needs, 3) Implement a monitoring program to address data gaps, and 4) Create a web-based 

map portal of monitoring activities. As part of the project, the USGS worked with stakeholders 

to inventory current programs and design a monitoring program. Results after 3 years of 

implementation will be discussed.   

1

Michelle Moorman, Biologist, US Geological Survey, North Carolina Water Science Center, Raleigh, NC 27607

Sharon Fitzgerald, Research Hydrologist, US Geological Survey. North Carolina Water Science Center, Raleigh, NC 27607

Keith Loftin, Research Chemist, US Geological Survey, Kansas Water Science Center, Lawrence, KS 66049

Elizabeth Fensin, Algal Ecologist, NC Department of Environment and Natural Resources, Division of Water Resources, Raleigh, NC 27699
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 273

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

PUBLICALLY ACCESSIBLE DECISION SUPPORT SYSTEM OF 

THE SPATIALLY REFERENCED REGRESSIONS ON WATERSHED 

ATTRIBUTES (SPARROW) MODEL AND MODEL ENHANCEMENTS 

IN SOUTH CAROLINA

Celeste Journey, Anne B. Hoos, David E. Ladd, 

John W. Brakebill, Richard A. Smith1

The U.S. Geological Survey (USGS) National Water Quality Assessment program has developed 

a web-based decision support system (DSS) to provide free public access to the steady-state 

SPAtially Referenced Regressions On Watershed attributes (SPARROW) model simulation results 

on nutrient conditions in streams and rivers and to offer scenario testing capabilities for research 

and water-quality planning. Access to the decision support system is through a graphical user 

interface available online at http://cida.usgs.gov/sparrow. Nationally, the SPARROW models are 

based on the modified digital versions of the 1:500,000-scale River Reach File and 1:100,000-scale 

National Hydrography Dataset stream networks.

 For South Carolina, the DSS has total nitrogen and total phosphorus models for the South 

Atlantic-Gulf and Tennessee Region based on the Enhanced River Reach File 2.0. The system can 

be used to estimate nutrient conditions in unmonitored streams in South Carolina and to produce 

estimates of yield, flow-weighted concentration, or load of nutrients in water under various landuse conditions, changes, or resource management scenarios. This model divides larger river basins 

into multiple stream catchments and models nutrient contributions by source inputs and land use 

within each of those catchments. The model information, reported by stream reach and catchment, 

provides contrasting views of the spatial patterns of nutrient source contributions, including those 

from urban (wastewater effluent and diffuse runoff from developed land), agricultural (farm 

fertilizers and animal manure), and specific background sources (atmospheric nitrogen deposition, 

soil phosphorus, forest nitrogen fixation, and channel erosion). However, the large scale and static 

nature of the model (modeled only for the 2002 water year) have produced some limitations on the 

application of the decision support system on the state level. 

To address those limitations, the USGS is working cooperatively with the Resources For the Future 

program to adapt the steady-state model for South Carolina to a dynamic model that will simulate 

seasonal-average loads, yields, and concentrations during the period 2001-2003. Temperature and 

an Enhanced Vegetation Index from Moderate Resolution Imaging Spectroradiometer (MODIS), a 

National Aeronautics and Space Administration Terra-satellite-borne sensor, will be used as input 

to the dynamic model to characterize seasonal uptake and release of nitrogen during land-to-water 

transport.   

1

Celeste Journey, Water Quality Specialist, US Geological Survey, SC Water Science Center, Columbia, SC 29210

Anne B. Hoos, Hydrologist, US Geological Survey, TN Water Science Center, Nashville, TN 37211

David E. Ladd, Hydrologist, US Geological Survey, TN Water Science Center, Nashville, TN 37211

John W. Brakebill, Supervisory Geographer, US Geological Survey, MD Water Science Center, Baltimore, MD 21228

Richard A. Smith, Hydrologist, US Geological Survey, Office of Water Quality, Reston, VA 20192 
274 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE MID-ATLANTIC REGIONAL WETLAND CONSERVATION 

EFFECTS ASSESSMENT PROJECT

Megan Lang, Greg McCarty, Mark Walbridge, Patrick Hunt, Tom Ducey, 

Clinton Church, Jarrod Miller, Laurel Kluber, Ali Sadeghi, Martin Rabenhorst, 

Amir Sharifi, In-Young Yeo, Andrew Baldwin, Margaret Palmer, Tom Fisher, 

Dan Fenstermacher, Sanchul Lee, Owen McDonough, Metthea Yepsen, 

Liza McFarland, Anne Gustafson, Rebecca Fox, Chris Palardy, William Effland, 

Mari-Vaughn Johnson, Judy Denver, Scott Ator, Joseph Mitchell, Dennis Whigham1

Wetlands impart many important ecosystem services, including maintenance of water quality, 

regulation of the climate and hydrological flows, and enhancement of biodiversity through the 

provision of food and habitat. The conversion of natural lands to agriculture has led to broad 

scale historic wetland loss, but current US Department of Agriculture conservation programs and 

practices seek to replace or ameliorate the ecosystem services lost to agricultural conversion. 

Wetland restoration can enhance watershed resiliency in the face of land use and climate change, 

and provide critical ecosystem services that enhance the condition of downstream waters. In 

addition, restored wetlands can directly influence climate change through the regulation of 

greenhouse gases and carbon sequestration. In order for the USDA to best allocate funds to 

improve environmental outcomes, a better understanding of the effects of wetland restoration 

practices is needed. The Mid-Atlantic Regional (MIAR) Wetland Conservation Effects Assessment 

Project (Wetland-CEAP) is a regional component of the national Wetland-CEAP which was 

initiated by the Natural Resources Conservation Service (NRCS) to develop a broad collaborative 

wetland science foundation that facilitates the production and delivery of scientific results. The 

MIAR is an interdisciplinary study which brings together scientists from multiple federal agencies 

and the University of Maryland to study non-tidal palustrine wetlands in the MIAR Coastal Plain, 

including prior converted croplands (historic wetlands) and natural and restored wetlands. The 

results and implications of an initial ground based study will be discussed and current efforts 

to extrapolate this information to a broader spatial and temporal scale via remote sensing and 

modeling will be described. Project findings are being used to assess and improve the effectiveness 

of conservation practices and Farm Bill programs affecting wetlands and associated lands in 

the Mid-Atlantic Coastal Plain. This project encourages future inter-agency cooperation and is 

an important step towards producing a national model that can be used to support the adaptive 

management of wetland restoration and enhancement programs.  

1

Megan Lang, Research Associate Professor, University of Maryland, Department of Geographical Sciences, Beltsville, MD 20705

Greg McCarty, Soil Scientist, USDA Agricultural Research Service, Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705

Mark Walbridge, National Program Leader, USDA Agricultural Research Service, Beltsville, MD 20705

Patrick Hunt, Research Leader, USDA Agricultural Research Service, Florence, SC 29501

Tom Ducey, Microbiologist, USDA Agricultural Research Service, Florence, SC 29501

Clinton Church, Chemist, USDA Agricultural Research Service, University Park, PA 16802

Jarrod Miller, Soil Scientist, USDA Agricultural Research Service, Florence, SC 29501

Laurel Kluber, Research Microbiologist, USDA Agricultural Research Service, Florence, SC 29501

Ali Sadeghi, Research Physicist, USDA Agricultural Research Service Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705

Martin Rabenhorst, Professor, University of Maryland, Environmental Science and Technology, College Park, MD 20742

Amir Sharifi, Research Associate, University of Maryland, Environmental Science and Technology, College Park, MD 20742

In-Young Yeo, Assistant Professor, University of Maryland, Department of Geographical Sciences, College Park, MD 20742

Andrew Baldwin, Associate Professor, University of Maryland, Environmental Science and Technology, College Park, MD 20742

Margaret Palmer, Professor, University of Maryland, Department of Entomology, College Park, MD 20742

(Author affiliations continued on page 275)
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 275

Poster Session

(Author affiliations continued from page 274)

Tom Fisher, Professor, University of Maryland, Center for Environmental Science, Cambridge, MD 21613

Dan Fenstermacher, Graduate Student, University of Maryland, Environmental Science and Technology, College Park, MD 20742

Sanchul Lee, Graduate Assistant, University of Maryland, Department of Geographical Sciences, College Park, MD 20742

Owen McDonough, Graduate Research Associate, University of Maryland, Center for Environmental Science, Cambridge, MD 21613

Metthea Yepsen, Graduate Student, University of Maryland, Center for Environmental Science, Cambridge, MD 21613

Liza McFarland, Graduate Student, University of Maryland, Environmental Science and Technology, College Park, MD 20742

Anne Gustafson, Senior Faculty Research Assistant, University of Maryland, Center for Environmental Science, Cambridge, MD 21613

Rebecca Fox, Assistant Research Scientist, University of Maryland, Center for Environmental Science, Cambridge, MD 21613

Chris Palardy, Graduate Student, University of Maryland, Environmental Science and Technology, College Park, MD 20742

William Effland, Soil Scientist, USDA Natural Resources Conservation Service, Beltsville, MD 20705

Mari-Vaughn Johnson, Agronomist, USDA Natural Resources Conservation Service, Beltsville, MD 20705

Judy Denver, Project Chief, US Geological Survey, Dover, DE 19901 

Scott Ator, Hydrologist, US Geological Survey, Baltimore, MD 21228

Joseph Mitchell, Owner, Mitchell Ecological Research Service, Ft. White, FL 32038

Dennis Whigham, Senior Botanist, Smithsonian Environmental Research Center, Edgewater, MD 21037
276 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

GUAM PAGO WATERSHED CONSERVATION

Maria Lynn Cruz, Laura F. Biggs1

The purpose of this research is to explore water science methodologies in determining the source 

of sedimentation in the Guam Pago Watershed. Watersheds provide drinking water, an agricultural 

water source, and forms of recreation. However, from years of soil erosion and several factors 

occurring inland, the mouth of Pago River has widened allowing a larger amount of sediment and 

nutrient rich water onto a greater area of coral. With the use of water science equipment such as 

the Manta turbidity logger and rain gauges, initial monitoring will focus on narrowing down the 

causes of sedimentation. In order to distinguish inland factors from coastal factors, loggers will 

be launched at an upstream point where the Sigua and Lonfit rivers converge, and at a point near 

the opening of Pago Bay. As a relatively small island, research and education are key in achieving 

and maintaining a sustainable environment. In order to encourage an action for improvement 

or mitigation to target behaviors within the target audience, this study is intended to increase 

scientific and community understanding of the effects of land usage on Pago Bay.  

1

Maria Lynn Cruz, Student, University of Guam Sea Grant, Mangilao, GU 96923

Laura F. Biggs, Assistant Professor, Outreach and Education Services, University of Guam, Mangilao, GU 96923
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 277

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

HAS THE PROMISE OF DNA BARCODING BEEN ACHIEVED? 

A CRITICAL LOOK AT THE APPLICATION 

OF EDNA BARCODING TO BIOMONITORING

Carolina Penalva-Arana, Erik Pilgrim, John Martinson1

Biological monitoring programs aim to assess the health of waters and determine the direct impact 

anthropogenic activities are having on the ecosystems. There is a need for the development of 

accurate and reproducible methods that can assess biodiversity rapidly and in a cost-effective 

manner. A system for tracking water quality changes brought on by such things as climate 

change, invasive species, nutrients, or pollution is imperative as these disturbances are occurring 

more often and in more places. A highly touted new strategy for evaluating biodiversity is the 

application of high throughput next generation sequencing to environmental DNA (eDNA), 

whereby the sequence of one or more specific genes can be used to distinguish between a wide 

range of species. This comprehensive view of an ecosystem can shed light on the health of an 

ecosystem by revealing the presence/absence of microbes to macroinvertebrates in a sample. 

In collaboration with Ohio EPA (OEPA) we aim to validate, in a field context, the efficacy of 

eDNA sequencing using multiple barcodes (eDNA barcoding) to identify species, and compare 

the species found by this method against those identified through standard morphological-based 

methods. Our results show little overlap between the 115 macroinvertebrate species identified 

by OEPA and the eDNA method, with only 15 species shared between samples. However, the 

eDNA barcoding approach identified a larger number of taxa that were not identified by OEPA 

taxonomist, demonstrating a potential underestimation of biodiversity and information relevant 

to water quality within this ecosystem. In addition, eDNA data is explored to identify microbes 

of interest to human and potentially indicative of ecosystem health. However, the question 

remains: Is the eDNA barcoding method, which can identify more taxa with less effort that current 

methodologies, a viable new tool for determining ecosystem health?

Disclaimer: The views expressed are those of the authors and do not necessarily reflect the views 

or policies of the US EPA.  

1

Carolina Penalva-Arana, Molecular Ecologist, US Environmental Protection Agency, National Center for Environmental Assessment, 

Washington, DC 20004

Erik Pilgrim, Research Biologist, US Environmental Protection Agency, National Exposure Research Laboratory, Cincinnati, OH 45268

John Martinson, Research Biologist, US Environmental Protection Agency, National Exposure Research Laboratory, Cincinnati, OH 45268
278 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

ASSESSING THE RELATIONSHIP BETWEEN FORESTS AND WATER IN 

THE HIGH ROCK LAKE WATERSHED OF NORTH CAROLINA

Tom A. Gerow, Jr., David G. Jones, and Wenwu Tang1

Forests are recognized as a priority source of relatively high quality and reliable water, be it for human 

use or ecological function. The High Rock Lake watershed straddles the piedmont and foothill regions 

of North Carolina, and a Total Maximum Daily Load (TMDL) restoration plan is being developed for 

the reservoir. The findings of the study should add to the body of knowledge regarding how forests can 

be a solution for protecting water resources, and may help to reduce the costs of treating public water 

supplies. Seventy-one datasets obtained over five years of benthic macroinvertebrates sampling within 

the watershed were analyzed, and used as a proxy for determining overall water quality. Estimates 

of the costs to treat water, and water quality grab sample data from thirteen public water systems in 

the watershed were also obtained and analyzed. Finally, a method was developed for conducting a 

GIS-based stream buffer land cover assessment, in an effort to localize the findings of the study and 

identify potential land parcels where forestry-related conservation practices may improve watershed 

health, function, or quality. This study identified a correlation between the extent of forest cover, and 

effects of other land cover types, with the quality of water for ecological function as well as the relative 

cost to treat public water supplies. When evaluating aquatic life Biotic Index and EPT Taxa Richness, 

better results were observed in those subwatersheds where the forest cover was approximately 37 to 48 

percent (or more) of the land use/land cover; and where natural cover was approximately 50 percent 

(or more) of the land use/land cover. Conversely, when urbanized or developed land cover exceeded 

approximately 20 percent, the measures for aquatic life worsened. These overall trends identified that 

the percent forest or natural cover can be a corollary indicator of the general quality of water, and that in 

this study area, better water quality was associated with those subwatersheds that were predominantly 

forested. Another aspect of this study examined the quality of water samples taken at multiple water 

supply intakes and associated cost estimates for treating the water for human use. A general trend was 

observed that indicated costs to treat the water were lower when the contributing watershed consisted of 

approximately 70 percent (or more) forest cover. Alternatively, higher costs to treat water occurred with 

increased turbidity, and turbidity was found to be higher when the amount of forest cover fell below 60 

to 70 percent of the watershed’s total land cover. An analysis was conducted of land cover / land use 

for each of the 127 subwatersheds (12-digit HUC) within the High Rock Lake watershed, to categorize 

each subwatershed in accordance with the identified “Forest Cover Model” thresholds related to forest 

cover and water quality, (i.e., forest cover is below 37 percent; or forest cover is between 37 and 48 

percent; or forest cover exceeds 48 percent.) The map generated from this analysis quickly identifies 

forest cover in relative terms, which can also be used to correlate the anticipated quality of water 

originating from each subwatershed. With this information, end users can quickly identify where in the 

watershed different approaches in deploying forest and land management best management practices 

(BMPs) may be appropriate, to sustain quality water resources, given the relative amount of forest cover 

in the subwatershed. In addition, a closer examination was made to evaluate the stream buffer structure 

and land cover within select subwatersheds to identify streams that could potentially benefit from 

forestry related conservation measures, with the presumption that improvements to its riparian buffer 

should translate to improvements to the stream itself. This High Rock Lake watershed assessment study 

was conducted by faculty, staff, and students of the Center for Applied GIS Science at the University of 

North Carolina at Charlotte, with funding and project oversight provided by staff of the North Carolina 

Forest Service, via grants from the USDA Forest Service and the USEPA.

1

Tom A. Gerow, Jr., Staff Forester for BMPs, North Carolina Forest Service, Raleigh, NC 27699

David G. Jones, Head of Geospatial Services Branch, North Carolina Forest Service, Raleigh, NC 27699

Wenwu Tang, Assistant Professor and Interim Executive Director, Center for Applied GIS Science, University of North Carolina at Charlotte, 

Charlotte, NC 28223
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 279

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

INTEGRATED RESEARCH – WATER QUALITY, SOCIOLOGICAL, 

ECONOMIC, AND MODELING – IN A REGULATED WATERSHED: 

JORDAN LAKE, NC

Deanna Osmond, Mazdak Arabi, Caela O’Connell, Dana Hoag, 

Dan Line, Marzieh Motallebi, Ali Tasdighi1

Jordan Lake watershed is regulated by state rules in order to reduce nutrient loading from point 

and both agricultural and urban nonpoint sources. The agricultural community is expected to 

reduce nutrient loading by specific amounts that range from 35 - 0 percent nitrogen, and 5 - 0 

percent phosphorus. In addition, trading is allowed and the development community is anxious to 

purchase credits within the agricultural community in the form of buffers. This multidisciplinary 

research project has explored different facets of agricultural nonpoint source abatement in 

Jordan Lake watershed. Two paired watershed experiments have detailed nutrient reductions 

through conservation systems on pasture or cropland. A detailed key-informant survey of farmer 

beliefs relative to conservation practice adoption and trading has documented that views about 

conservation practice adoption are complex and vary based on farmers’ experiences, socialnetworks, and personal beliefs about each practices’ utility, impact and outcomes. Socioeconomic 

analysis indicates that despite general support for water quality improvements, the majority of 

farmers were disinterested in participating in the trading program for financial, environmental, 

and pragmatic reasons related to the specifics of the trading program. Water quality modeling 

suggests that nutrient loads are reduced in agricultural areas relative to urban areas. Furthermore 

many agricultural fields have no nitrogen credits to trade and those that can trade have only a 

small amount. Lastly, economic analysis indicates that the price of nutrients available for trades 

likely will be too high for trades to occur, especially when the costs of trading are considered. 

Supply of credits is very low, which significantly increases transaction costs. In addition, a survey 

of local farmers showed that they would require a significant financial premium above the cost of 

conservation practices to adopt them since they are unfamiliar with the conservation practices and 

lack trust about how the program would work. Financial compensation from developers increases 

the likelihood of participation, but will likely be insufficient to initiate trades in this region.

1

Deanna Osmond, Professor and Soil Science Department Extension Leader, Department of Soil Science, NC State University, Raleigh, NC 27695

Mazdak Arabi, Associate Professor, College of Engineering, Colorado State University, Fort Collins, CO 80523

Caela O’Connell, Doctoral Candidate, Department of Anthropology, UNC-Chapel Hill, Chapel Hill, NC 27599

Dana Hoag, Professor, College of Agricultural Sciences, Colorado State University, Fort Collins, CO 80523

Dan Line, Extension Specialist, Department of Biological and Agricultural Engineering, NC State University, Raleigh, NC 27695

Marzieh Motallebi, Doctoral Candidate, Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO 80523

Ali Tasdighi, Doctoral Candidate, Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO 80523
280 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATER USE EFFICIENCY AT BASIN AND FARM SCALES

Ehsan Goodarzi, Lotfollah Ziaei, Saeid Eslamian1

The available water resources in basins are becoming scarce while demands for water are 

considerably increasing among various sectors due to economic and population growths. Water 

deficiency is becoming a main constraint for sustainable regional development and it is the 

primary motivation in creating water to supply user requirements in particular for agricultural 

demands within a basin. As agriculture is the largest water user at the global level, the general 

focus has been on getting higher efficiency by changing irrigation system or improving irrigation 

scheduling to reduce the water shortage effects. In addition, significant efforts are being placed to 

improve water usages efficiency and optimize water consumptions by developing systematic and 

implementable plans. One way to preserve existing natural water resources is using recycled water. 

For instance in the case of farm lands irrigation, water is almost never wholly finished since the 

amount of that drains away in the forms of surface runoff and deep percolation can be returned 

into the system. In other words, the only real loss in the basin scale is evaporation. Based on the 

classical concepts of water efficiency, all of the wasted water including evaporation, surface runoff 

and deep percolation are lost, whereas both surface runoff and deep percolation can be reentered 

into the system and added to the surface or ground water bodies to be used again by downstream 

users. Considering the return flows as part of available water resources and reuse it is known 

as multiplier effect of water recycling. To better understand the potential impacts of irrigation 

interferences at a water basin scale, the multiplier effect of water recycling from an irrigation 

perspective is studied in the Zayandeh Rud basin located in the central part of Iran. This study is 

developed in a general manner to describe how the efficiency of system can be different from farm 

to basin scales.

1

Ehsan Goodarzi, Research Scientist, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332

Lotfollah Ziaei, Water Resources Engineer, Zayandab Consulting Engineers Co, Isfahan, Iran 

Saeid Eslamian, Associate Professor of Hydrology, Isfahan University of Technology, Isfahan, Iran 
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 281

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

GROUNDWATER AVAILABILITY IN THE CROUCH BRANCH 

AND MCQUEEN BRANCH AQUIFERS, CHESTERFIELD COUNTY, 

SOUTH CAROLINA, 1900–2012

Bruce Campbell, James E. Landmeyer1

Chesterfield County is located in the northeastern part of South Carolina along the southern border 

of North Carolina and is primarily underlain by unconsolidated sediments of Late Cretaceous age 

and younger of the Atlantic Coastal Plain. Approximately 20 percent of Chesterfield County is 

in the Piedmont Physiographic Province, and this area of the county is not included in this study. 

These Atlantic Coastal Plain sediments compose two productive aquifers: the Crouch Branch 

aquifer that is present at land surface across most of the county and the deeper, semi-confined 

McQueen Branch aquifer. Most of the potable water supplied to residents of Chesterfield County 

is produced from the Crouch Branch and McQueen Branch aquifers by a well field located near 

McBee, South Carolina, in the southwestern part of the county. 

The primary purpose of this study was to determine groundwater-flow rates, flow directions, and 

changes in water budgets over time for the Crouch Branch and McQueen Branch aquifers in the 

Chesterfield County area. This goal was accomplished by using the U.S. Geological Survey finitedifference MODFLOW groundwater-flow code to construct and calibrate a groundwater-flow 

model of the Atlantic Coastal Plain of Chesterfield County. The model was created with a uniform 

grid size of 300 by 300 feet to facilitate a more accurate simulation of groundwater-surface-water 

interactions.

 The calibrated groundwater-flow model was then used to calculate groundwater budgets for the 

entire study area and for two sub-areas. The sub-areas are the Alligator Rural Water and Sewer 

Company well field near McBee, South Carolina, and the Carolina Sandhills National Wildlife 

Refuge acquisition boundary area. For the overall model area, recharge rates vary from 56 to 1,679 

million gallons per day (Mgal/d) with a mean of 737 Mgal/d over the simulation period (1900-

2012). The simulated water budget for the streams and rivers varies from 653 to 1,127 Mgal/d with 

a mean of 944 Mgal/d. The simulated “storage-in term” ranges from 0 to 565 Mgal/d with a mean 

of 276 Mgal/d. The simulated “storage-out term” has a range of 0 to 552 Mgal/d with a mean of 

77 Mgal/d. Groundwater budgets for the McBee, South Carolina, area and the Carolina Sandhills 

National Wildlife Refuge acquisition area had similar results.

1

Bruce Campbell, Hydrologist, US Geological Survey, SC Water Science Center, Columbia, SC 29210

James Landmeyer, Hydrologist, US Geological Survey, SC Water Science Center, Columbia, SC 29210
282 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

DEVELOPING A DROUGHT EARLY WARNING INFORMATION SYSTEM 

FOR COASTAL ECOSYSTEMS IN THE CAROLINAS

Kirsten Lackstrom, Amanda Brennan, Paul Conrads, 

Lisa Darby, Kristin Dow, Daniel Tufford1

The National Integrated Drought Information System (NIDIS) and the Carolinas Integrated 

Sciences and Assessments (CISA), a National Oceanic and Atmospheric Administration (NOAA)-

funded Regional Integrated Sciences and Assessments (RISA) program, are partnering to develop 

and support a Carolinas Drought Early Warning System pilot program. Research and projects 

focus on the unique coastal ecosystems in North and South Carolina. In the Carolinas, drought 

effects on environmental resources, particularly in coastal areas, are not as well-understood, or 

as well-integrated into existing drought planning and response processes, as other impacts and 

resources (such as, agriculture, surface water supplies).

 Key concerns related to drought and coastal ecosystems focus on impacts to water quality and 

quantity, habitats, species, and estuarine processes.

• Drought contributes to increased salinity and saltwater intrusion, reduced flushing and 

assimilation of pollutants, and overall water quality changes.

• Ecosystem impact concerns center on habitat loss or conversion and consequent effects 

on recruitment, distribution, and migration patterns as well as on primary and secondary 

production.

• Saltwater intrusion, low stream flows, and low water levels contribute to impacts and are 

attributed to both drought and human actions (e.g. changes in dam releases due to drought).

This poster will highlight current activities to develop a drought early warning information system 

in the Carolinas:

• Development of a coastal drought index based on U.S. Geological Survey (USGS) real-time 

salinity data

• Assessment of ecological indicators of drought in southeastern coastal ecosystems

• Development of an ‘Atlas of Hydroclimate Extremes’ for the Carolinas

• Assessment of drought indicators for coastal zone fire risk

• Forecasting the SC blue crab fishery using real-time freshwater flow data

• Increasing coastal observations of drought through citizen science and the Community 

Collaborative Rain, Hail, & Snow Network (CoCoRaHS)

1

Kirsten Lackstrom, Program Manager, Carolinas Integrated Sciences & Assessments, University of South Carolina, Columbia, SC 29208

Amanda Brennan, Climate Outreach Specialist, Carolinas Integrated Sciences & Assessments, University of South Carolina, Columbia, SC 29208

Paul Conrads, Hydrologist, US Geological Survey, South Atlantic Water Science Center, Columbia, SC 29210

Lisa Darby, National Oceanic and Atmospheric Administration, Earth System Research Laboratory, Boulder, CO 80305

Kirstin Dow, Professor, Carolinas Integrated Sciences & Assessments and Department of Geography, University of South Carolina, 

Columbia, SC 29208

Daniel Tufford, Professor, Carolinas Integrated Sciences & Assessments and Department of Biological Sciences, University of South Carolina, 

Columbia, SC 29208
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 283

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

PRECIPITATION PARTITIONING IN SHORT ROTATION 

BIOENERGY CROPS: IMPLICATIONS FOR DOWNSTREAM 

WATER AVAILABILITY

Peter Caldwell, Chelcy F. Miniat, Doug Aubrey, 

Rhett Jackson, Jeff McDonnell1

The southern United States is a potential leader in producing biofuels from intensively 

managed, short rotation (8–12 years) woody crops such as southern pines, and native and 

non-native hardwoods. However, their accelerated development under intensive management 

has raised concerns that fast-growing bioenergy crops could reduce recharge to stream flows 

and groundwater, relative to other land cover types or less intensively managed woody crops. 

In this study, we characterize and compare the partitioning of precipitation into interception, 

transpiration, throughfall, infiltration, and soil evaporation for 12-year-old, intensively managed 

loblolly pine (Pinus taeda) and sweetgum (Liquidambar styraciflua) stands at the Department of 

Energy Savannah River Site in New Ellenton, South Carolina. Three replicate plots of each species 

were instrumented with sap flow probes, box lysimeters, integrated temperature and soil moisture 

probes, precipitation gauges, and throughfall gauges to allow estimation of the components of 

the total water balance and to parameterize process-based models. Preliminary soil moisture 

measurements show that annual Relative Extractable Water (REW) is similar between sweetgum 

and loblolly pine plots (0.43); however, REW was significantly lower in sweetgum compared to 

loblolly plots in the summer (0.41 vs. 0.53), but higher in early spring months (0.63 vs. 0.58). 

These results suggest comparable annual water use by sweetgum and loblolly pine, but higher 

water use by sweetgum than pine during the growing season, and higher water use by loblolly pine 

than sweetgum during the dormant season. This work will provide key insights on the implications 

of bioenergy crop expansion in the South for loblolly and sweetgum.

1

Peter Caldwell, Research Hydrologist, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763

Chelcy F. Miniat, Research Project Leader, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763

Doug Aubrey, Assistant Professor, Deptartment of Biology, Georgia Southern University, Statesboro, GA 30460

Rhett Jackson, Professor, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602

Jeff McDonnell, Professor, School of Environmental Sustainability, University of Saskatchewan, Saskatoon, SK Canada S7N 5B5
284 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

VARIATIONS IN CANOPY AND LITTER INTERCEPTION 

ACROSS A FOREST CHRONOSEQUENCE IN THE 

SOUTHERN APPALACHIAN MOUNTAINS

Steven T. Brantley, Paul V. Bolstad, Stephanie H. Laseter, 

A. Christopher Oishi, Kimberly A. Novick, Chelcy F. Miniat1

Variations in evapotranspiration (ET) have been well documented across a variety of forest types 

and climates in recent decades; however, most of these data have focused on mature, secondgrowth stands. Here we present data on two important fluxes of water, canopy interception (Ic) 

and forest floor litter interception (Iff), across a chronosequence of forest age in the southern 

Appalachian Mountains. We used climate stations and throughfall collectors to measure gross 

rainfall and estimate Ic at each site and used a non-linear mixed model to determine the effects of 

forest age and precipitation on stand Ic. We also collected forest floor biomass monthly at each site 

and used these data in a model of litter wetting and drying to determine the quantity of water lost 

to Iff. Precipitation varied from 1679 to 2095 mm yr-1 across sites and across years (2011–2013). 

Canopy interception increased rapidly with forest age and then leveled off to a maximum of 

~11percent in an old-growth mixed hardwood site. Despite differences in forest structure, forest 

floor biomass did not vary with age, suggesting either lower decomposition rates in younger sites, 

or likely high decomposition rates across all sites. Unlike Ic, modeled estimates of interannual 

variation in Iff were insensitive to annual rainfall amount and were dependent primarily on 

forest floor biomass. At all sites, Iff accounted for 4–6 percent of total precipitation and varied 

primarily due to differences in rainfall among sites with a higher percentage of Iff in sites with 

lower rainfall. Additional measurements are currently underway to validate the litter interception 

model using litter moisture probes and forest floor wet and dry weights. Improved estimates of 

interception will contribute to our understanding of how forest structure and climate variability 

affect forest water use and help improve models of rainfall partitioning across the broader matrix 

of forest age classes.

1

Steven T.Brantley, Assistant Research Scientist, Joseph W. Jones Ecological Research Center, Newton, GA 39870

Paul V. Bolstad, Professor, Department of Forest Resources, University of Minnesota, Minneapolis, MN 55455

Stephanie H. Laseter, Hydrologist, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA Forest 

Service, Otto, NC 28763

A. Christopher Oishi, Research Ecologist, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763

Kimberly A. Novick, Assistant Professor, School of Public and Environmental Affairs, Indiana University, Bloomington, IN 47408

Chelcy F. Miniat, Research Project Leader, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 285

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

RESTORATION OF SOUTHERN APPALACHIAN RIPARIAN FORESTS 

AFFECTED BY EASTERN HEMLOCK MORTALITY

Katherine Elliott, Chelcy F. Miniat, Jennifer Knoepp, 

Michael A. Crump, C. Rhett Jackson1

Widespread mortality of eastern hemlock (Tsuga canadensis) through hemlock woolly adelgid 

(HWA) infestation has altered riparian forest structure and function throughout the southern 

Appalachians. Eastern hemlock and Rhododendron maximum often co-occur in these riparian 

forests, where the latter species is highly shade tolerant, forms a dense shrub layer that strongly 

attenuates light incident on the forest floor, has little to no herbaceous cover below its canopy, 

negatively affects tree seedling recruitment, and decreases nitrogen availability in the soil and 

litter layer to non-ericaceous species. In these forests, post-mortality successional dynamics may 

well be dominated by rhododendron. We hypothesize that removal of rhododendron will improve 

these degraded forests by restoring structure and function: allowing recruitment of trees and herbs; 

increasing forest floor decomposition rates; increasing soil pH, nutrient availability and nutrient 

cycling rates; and, subsequently, raising stream pH and acid neutralizing capacity (ANC). 

Here we report on a study in which we are conducting rhododendron and forest floor removal 

experiments in riparian corridors once dominated by eastern hemlock at two spatial scales: 

intensive plot scale, and un-replicated stream reach scale. For the former, sixteen 20 x 20 m 

replicate plots comprise a fully factorial experiment wherein aboveground rhododendron biomass 

removal, and O-horizon removal has two levels (removal or not). For each treatment, we are 

measuring microenvironment changes, the rate of recovery in vegetation dynamics (growth and 

recruitment), and nutrient pools and fluxes, and on the reach scale plots we are also measuring 

stream water quality, and in-stream processes. Pre-treatment measurements are ongoing and 

reported here. We will impose the rhododendron and O-horizon removal treatments in Mar-May 

2015. Active and adaptive management strategies will be required to transform degraded riparian 

systems into more desirable states. Land managers need science-based restoration methods to aid 

recovery of forest structure and function after widespread loss of an important species.

1

Katherine Elliot, Research Ecologist, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763 

Chelcy F. Miniat, Research Project Leader, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763

Jennifer D. Knoepp, Research Soil Scientist, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, 

USDA Forest Service, Otto, NC 28763

Michael A. Crump, Hydrologist, Biological and Physical Resources, Southern Region, USDA Forest Service, Palmer, PR 00721

C. Rhett Jackson, Professor, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602
286 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

PHYSIOLOGICAL RESPONSES OF EASTERN HEMLOCK (TSUGA 

CANADENSIS) TO BIOLOGICAL CONTROL AND SILVICULTURAL 

RELEASE: IMPLICATIONS FOR HEMLOCK RESTORATION

Chelcy F. Miniat, David Zeitlow, Steven T. Brantley, Albert Mayfield, 

Rusty Rhea, Robert Jetton, Paul Arnold1

The rapid loss of eastern hemlock (Tsuga canadensis) from riparian zones in the southern 

Appalachian Mountains due to Hemlock Woolly Adelgid (Adelgis tsugae, HWA) infestation has 

resulted in changes to watershed structure and function. Several restoration strategies have been 

proposed, including silvicultural treatments that increase incident light in forest understories, and 

the introduction of predator beetles to control populations of HWA. We conducted separate nursery 

and field experiments to investigate the physiological effects of releasing eastern hemlock from 

light limitation. We hypothesized that higher light levels and reduced infestation from biological 

control would improve tree carbon balance. The nursery experiment exposed HWA-infested 

seedlings to five different incident light levels (from 0–90 percent shade). The field experiment 

was conducted in mixed hardwood stands with eastern hemlock in the understory that were either 

uninfested or infested with HWA, and either with or without predator beetles (Sasajiscymnus 

tsugae) present (Control, Infested, Infested+Predator). In the field experiment, in each stand 

(C, I, I+P), we targeted half of the eastern hemlock trees to have 0.125 ha gaps created around 

them. In both experiments we compared short- and long-term indices of physiological stress (leaf 

net photosynthesis, or Anet; leaf fluorescence, or Fv/Fm; and total non-structural carbohydrate 

content, or TNC) to test for improvements in hemlock leaf physiology and carbon balance in 

response to these treatments. In the nursery experiment, there was no variation in Fv/Fm among 

treatments and Anet was inversely related to light availability; however, TNC increased with 

increasing light exposure. In the forest gaps, Fv/Fm showed that trees were stressed immediately 

after gap creation, but started to acclimate to increased light within a few weeks. Trees in gaps 

had higher Anet and TNC than non-gap trees. TNC was highest in uninfested trees, followed by 

infested trees with predator beetles, and then infested trees with no predator beetles. Our results 

indicate that combining biological control with silvicultural treatments may improve long-term 

survival of infested trees and be an effective restoration treatment.

1

Chelcy F. Miniat, Research Project Leader, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763

David Zeitlow, Graduate Student Researcher, Coweeta Hydrologic Laboratory, Southern Research Station, USDA Forest Service, Otto, NC 28763

Steven T. Brantley, Assistant Research Scientist, Joseph W. Jones Ecological Research Center, Newton, GA 39870

Albert Mayfield, Research Entomologist, Southern Research Station, USDA Forest Service, Asheville, NC 28804

Rusty Rhea, Entomologist, Forest Health Protection, Southern Region, USDA Forest Service, Asheville, NC 28804

Robert Jetton, Research Assistant Professor, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695

Paul Arnold, Professor and Chair, Department of Biology, Young Harris College, Young Harris, GA 30582
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 287

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

REGIONAL EFFORTS TO PROMOTE FORESTRY BEST 

MANAGEMENT PRACTICES: A SOUTHERN SUCCESS STORY

Herb Nicholson, John Colberg, Hughes Simpson, 

Tom Gerow, Wib Owen1

The Southern Group of State Foresters has a long history of water resource protection efforts, 

providing leadership in BMP development, improvement, and implementation, enhancing state 

BMP programs, establishing effective partnerships, and standardizing an approach to consistently 

monitor implementation across the region.

1

Herb Nicholson, Environmental Program Manager: BMP Program, South Carolina Forestry Commission, Columbia, SC 29221

John Colberg, State Water Quality Program Coordinator, Georgia Forestry Commission, Dry Branch, GA 31020

Hughes Simpson, Coordinator, Water Resrouces and Ecosystem Services, Texas A&M Forest Service, College Station, TX 77845

Tom Gerow, Staff Forester for BMPs, North Carolina Forest Service, Raleigh, NC 27699

Wib Owen, Executive Director, Southern Group of State Foresters, Garner, NC 27529
288 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

WATER USE ASSESSMENTS SUPPORTING COMPANY-SPECIFIC 

GROWTH AND SUSTAINABILITY GOALS

John Beebe1

Abstract—In areas with increasing demand for water, addressing water use objectives has long been a primary 

environmental objective and key concern among industrial water users including paper mills and other forest product 

companies. However, in recent years, water use metrics and related information (including population change, climate 

information, and land use characterization) have gained considerable importance to companies for addressing longer-term 

goals pertaining to growth and sustainability when it comes to water availability. One effort underway, lead by the National 

Council for Air & Steam Improvement, Inc. (NCASI), has compiled water metrics and related watershed information as a 

means for better understanding and projecting the demands for water in various parts of the country. This paper provides 

details on specific components of the effort to document water-related information on a case-by-case basis, as well as 

provide summary information and key findings culminating from this assessment.

INTRODUCTION

Many industries rely on access to natural water resources 

for use in the manufacturing of consumer goods and 

materials. With an increasing overall population, 

relocation of inhabitants away from rural areas, as well 

as the recurrence of droughts in certain parts of the 

country, forest products companies are more cognizant 

of information that is vital to supporting their long-term, 

sustainable water use goals. These goals extend to: a) 

overall water resources/availability, b) water stewardship, 

c) protecting against environmental degradation, and d) 

environmental sustainability in general.

With a greater understanding of the factors and constraints 

on water resources, companies can be better positioned 

to interact with other water stakeholders and make better 

long-term decisions for their facilities and the surrounding 

environment. Representing pulp and paper manufacturers 

as well as the wood products industry and forest 

landowners, NCASI has developed a comprehensive 

database of water use metrics and watershed-related 

information for their member companies. This database 

for water resource managers and ensuing watershed 

reports for NCASI members offer a means for companies 

to be helpful water stewards and creates an information 

resource that is unlike that of any other industry.

Detailed reports for each company (see fig. 1) include 

available water source and water withdrawal information, 

population metrics, data on public water needs (including 

municipal water supplies), water intakes and discharge 

information for each facility, local climate information 

(e.g., subbasin precipitation averages), various watershed 

characteristics, and upstream/downstream water use 

information (by use category). Each report generated 

as part of this effort relied on the compilation and/or 

assessment of demographic information and various 

environmental metrics into a database and corresponding 

GIS (fig. 2). Other components of the database and 

associated reports include land use composition, change 

in river flow (near each facility), influent & effluent 

ratios (i.e., relative to receiving stream & surface water 

flows), cooling water vs. process flow volumes, as well 

as a recent addition of information on the presence of 

threatened and endangered aquatic species (or their 

critical habitat designations) in mill receiving waters.

DATA SOURCES

The principal data sources for these assessments include 

the NCASI Environmental Data Resource & Receiving 

Water Database, Fisher International’s global mill 

database, the National Land Cover Database (NLCD), 

county population statistics from the U.S. Census Bureau 

(USCB),2 the USGS National Water-Use Information 

Program,3 EPA’s PCS & ICIS databases,4 as well as the 

2 U.S. Department of Commerce - Census Bureau (www.census.gov)

3 U.S. Geological Survey National Water-Use Information Program 

(water.usgs.gov/watuse/wunwup.html)

4 EPA Permit Compliance & Integrated Compliance Information 

Systems (www.epa.gov/enviro/pcs-icis-overview)

1

Senior Research Scientist, National Council for Air & Stream Improvement, Inc., Northern Regional Center, Kalamazoo, MI 49008
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 289

Poster Session

EPA WATERS database5 for CWA §303(d) impairment 

data. Additional demographic information for this 

summary was provided by the U.S. Census Bureau 

(USCB 2012) and obtained from EPA-ECHO6 Detailed 

Facility Reports.

PROCEDURES

Reports were generated to summarize data on industry 

facilities and their environment, as well as provide 

references to data sources corresponding to each reporting 

element. Source references in their electronic form, shown 

as blue hyperlinks on each report (fig. 1 & 2), provide 

access to supplementary information, and each batch 

of reports generated for NCASI member companies is 

accompanied by a definitions sheet providing detailed 

descriptions of each piece of information including 

corresponding data sources.

Each facility water-use/watershed characterization 

report also contains standard watershed metrics including 

waterbody identifier (i.e., NHD ComID#), surface 

5 EPA Watershed Assessment, Tracking & Environmental Results 

System (www.epa.gov/waters)

6 EPA Enforcement & Compliance History Online (www.epa-echo.gov)

water name and type (i.e., river/stream), stream order, a 

description of average flow conditions, relative location of 

the immediate receiving water reach within the watershed, 

cumulative drainage area, stream network density/

bifurcation, etc,.

Watershed information assembled as part of this effort is 

designed to not only generate facility-specific information 

useful to companies that comprise the forest products 

industry, but also to produce a database of water-related 

and other environmental metrics that can be used as a 

research tool to analyze information for the industry on 

a national or regional basis, as well as look for trends in 

mill demographic and other data over time.

RESULTS AND DISCUSSION

In terms of water sources, one component of the reports 

is the amount of potentially accessible surface water (or 

“open water”) nearby, expressed as a percentage of total 

land area within a set radius from each mill. While this 

metric may not be specific to the corresponding watershed 

for some facilities, it provides a crucial piece of water 

resource information for companies and the industry as 

whole. Overall, the amount of nearby open water around 

pulp and paper facilities in the U.S. averages 8.1 percent 

Figure 1—Top portion of combined water use/watershed characterization report for an example (i.e., hypothetical) 

facility scenario.
290 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Figure 2—Example facility scenario and lower portion of corresponding mill watershed with upstream area 

shown (highlighted), downstream area (shaded light gray), surrounding subwatersheds (shaded gray), and 

example watershed characterization report (embedded graphic).
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 291

Poster Session

of the total land area. And, while slightly more than 10 

percent of all industry facilities are located in areas in 

which the surrounding land mass contained greater than 

20 percent open water (e.g., large lakes and rivers), the 

amount of available water is less than 10 percent for 

about three quarters of all U.S. facilities. It was also noted 

that about five percent of this industry’s mills across the 

country have less than 1 percent open water nearby.

The surrounding land uses of the watershed also provided 

important information for individual facilities and, 

using the database corresponding to this report, can be 

summarized for broader areas involving multiple facilities 

or for groups of facilities owned by the same company 

for making water use decisions. At the national level we 

found that the area upstream of all facilities currently 

averages about 58 percent forestland (compared to 51 

percent downstream), and approximately 21 percent is 

classified as agricultural land (compared to 27 percent 

downstream). Wetlands also comprise a significant area 

of the industry’s watersheds, averaging 7.5 percent of 

the upstream drainage area (compared to 9.0 percent 

downstream), whereas grassland and other/mixed land 

classifications average 6.3 percent upstream (versus 

only 2.4 percent downstream). Collectively, urban areas 

comprise only 3.1 percent of upstream drainage areas (and 

nearly double that amount with 6.1 percent of downstream 

areas).

Since the composition of urban and agricultural/rural 

land in the vicinity of a mill can have a dramatic effect 

on local water availability, we also compiled similar land 

classification percentages for the urban areas and rural 

lands around each facility (similar to the metric for water 

availability) as well as on a per-county basis. Facilities 

areas were characterized further by population density 

using Census data and found that the large majority of 

mill locations are in predominantly rural areas, with an 

average of 92.5 percent rural (per USDA-ERS definition) 

across all facilities, and about half (or 51 percent) of 

facilities with greater than 95 percent rural land. Less 

than 5 percent of facilities are located in or near cities 

with greater than 90 percent urban land. On a countyby-county basis, more than half of all U.S. pulp & paper 

mills are located in counties that are greater than 95 

percent rural and more than 75 percent of all facilities are 

located in counties that are greater than 80 percent rural 

(Figure 3). While mills located in the same watersheds 

as metropolitan areas or associated reservoirs potentially 

face critical water shortages, the large percentage of mills 

located in rural areas suggests agricultural water use may 

be of greater importance than city or overall water use.

Demographically, among the more than 200 mills in 

the U.S., the industry facility associated with the fastest 

growing population is located near Boston, MA (with a 

population increase in the associated county of nearly 

19,000 persons over a recent 2-year period), followed 

by facility locations in counties near Portland, OR 

(increasing 7,750 over the same 2-year period), near 

Newark, NJ (increasing 7,650), and near Charleston, SC 

(increasing by 7,380 persons). It is also worth noting 

that mills with the highest population densities in the 

immediate vicinity (i.e., within a 3-mile radius) include 

a mill located in Tacoma, WA mill with greater than 

3,500 inhabitants per square mile (IPSM), followed 

by two facilities in Green Bay, WI with about 3,200 

IPSM. By comparison, and providing a more general 

characterization of population sparseness for the industry, 

the average population density for the remaining mills 

is less than 450 IPSM. Census data also indicated 

that the trend in population for people living near 

most facilities increased slightly over a recent 10-year 

period, but from the most recent comprehensive Census 

information (USCB 2012), the population at the county 

level corresponding to mill locations shows a decrease in 

population for nearly half (i.e., about 46 percent) of our 

industry’s mills.

The NCASI database also contains information on 

the surface waters utilized by the industry and the 

corresponding influent (intake) volumes, as well as 

detailed information on individual facility receiving 

waters and their corresponding effluent (i.e., discharge) 

quantities. In terms of average river flow for facilities 

that discharge to U.S. surface waters, receiving waters 

across the forest products industry collectively average 

about 22,000 million gallons per day (MMGD) or about 

34,000 cubic feet per second (CFS), and the difference 

in flow from immediately upstream of the facilities to 

immediately downstream (while accounting for flow 

generated from point source discharges) varied from as 

little as 3 CFS in smaller headwater systems to 15,000 

CFS or more in larger river systems. This same metric 

averages 1,380 CFS across all mill receiving waters. 

Increases in flow were also documented and expressed 

as a percentage, which in the U.S. averages a 19 percent 

increase downstream compared to the corresponding 

upstream flow for all facilities. As for quantifying 

influents and effluents relative to total surface water 

volumes, the proportion of water brought into facilities 

currently averages 2.1 percent of the corresponding 

waterbodies throughout the industry, and the percentage 

of mill effluent discharge volumes to receiving water flow 

in the immediate reach of the corresponding rivers and 

streams averages about the same, just 2.0 percent.

Facility water use, including both mill process water and 

non-contact cooling water, across the country averages 

about 6.25 MMGD (or 9.7 CFS) per mill. By comparison, 

total water withdrawals from surface waters from all 

sources (including for agriculture, other industries, and 
292 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

domestic uses) exceeds 1,000 MMGD in a few industry 

counties. The average across all counties in which mills 

operate is 168 MMGD, which represents an average 

increase of 8 percent (from 154 MMGD) over a recent 

10-year period (i.e., 2000 to 2010). In terms of total 

water use in these counties by category, the vast majority 

was withdrawn by hydroelectric facilities (70 percent), 

followed by industrial sources (14 percent), agriculture/

irrigation (7 percent), domestic water use (6 percent), as 

well as mining and other sources (3 percent).

CONCLUSION

Reports generated from this effort summarize data on 

industry facilities and their environment, and provide 

detailed characterization reports containing standard 

watershed metrics, descriptions of average flow 

conditions and nearby water sources, as well as water 

use information for this industry and other industrial/

non-industrial (e.g., domestic) uses. Assembling 

this information not only generated facility-specific 

information useful to NCASI member companies, but 

also generated a database of water/environment-related 

metrics that can be used to analyze information at various 

scales, as well as look for trends in data over time. Data 

from these assessments can also be overlapped with 

water quality assessment information (e.g., EPA CWA 

§303(d) impairments) to help anticipate which facilities 

with certain watershed characteristics are more likely 

to be involved in a water quality improvement (e.g., 

TMDL) effort. In addition, more recent information 

on threatened and endangered species in mill receiving 

waters is helping to identify which industry facilities may 

require additional considerations for the volumes of water 

intake and/or discharge flows to not negatively impact 

aquatic ESA species and/or their critical habitat. Other 

demographic information used (but not described herein) 

may also be useful to specific companies or facilities in 

their water use decisions and related environmental 

sustainability goals.

LITERATURE CITED

USCB. 2012. Population Estimates – Current Estimates Data 

(2012 Statistical Abstract). 131st Edition. Washington, DC: 

U.S. Census Bureau. http://www.census.gov/popest/data. 

[Date accessed: November 17, 2014]

Figure 3—Facility locations showing predominantly rural land settings except for counties located in and around 

U.S. metropolitan areas.
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 293

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

INCREASING ALUMINIUM LEVELS IN NOVA SCOTIA, CANADA

S. MacLeod, S. Ambrose, J. Archibald, T. Clair, J. Minichiello, S. Sterling1

Global acidification of water catchments has resulted in increased mortality of aquatic organisms 

and the release of toxic metals from surrounding geology. In regions where recovery has not been 

observed, the mobility of aluminium is possible in the low pH values, and has been associated with 

the deaths of Salmo salar. We investigate the long-term trends of aluminium, ionic aluminium 

and other stream ions in Mersey River, Nova Scotia, Canada to determine whether aluminium 

should be considered a threat to local S. salar populations. Data has been obtained from 1980 

to 2014 from Environment Canada, and interpolated for weekly averages. A modified empirical 

formula is used to estimate ionic aluminium. Total aluminium and ionic aluminium show increases 

since 1980, with changes of 2.2 μg L-1 yr-1 and 0.1 μg L-1 yr-1 respectively. The ionic aluminium 

exceeds the toxic threshold of 15 μg L-1 for salmon more frequently in the 2000s. There is no 

sign of recovery or leveling off of aluminium in the near future, which threatens the livelihood of 

S. salar in Nova Scotia rivers. More research is required to uncover the source of the increasing 

aluminium, and to refine the ionic aluminium empirical equation for a better understanding of the 

long-term trends. Aluminium can no longer be considered a minor problem in Nova Scotia rivers, 

and should be addressed before total extirpation of S. salar populations.

1

S. MacLeod, Graduate Student, Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada B3H 4R2

S. Ambrose, Graduate Student, Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada B3H 4R2

J. Archibald, Professor, Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada B3H 4R2

T. Clair, Research Associate, Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada B3H 4R2

J. Minichiello, Honors Undergraduate Student, Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada B3H 4R2

S. Sterling, Assistant Professor, Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada B3H 4R2
294 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

PRIORITIZING CATCHMENTS FOR TERRESTRIAL LIMING 

IN NOVA SCOTIA

Marley Geddes, Shannon Sterling1

Chronic acidification of freshwater systems is a major issue in South Western Nova Scotia 

(SWNS), Canada. Despite reductions in sulphur emissions, water quality has not improved and is 

not predicted to improve naturally for another 60 years. This is concerning because acidification 

is a limiting factor for the Southern Upland (SU) Atlantic salmon (Salmo salar) which were 

evaluated as endangered by the Committee on the Status of Endangered Wildlife in Canada 

(COSEWIC) in 2010. Population modelling for two of the largest populations within the SU 

designatable unit (LaHave and St. Mary’s rivers) indicate a high probability of extirpation (87 

percent and 73 percent, respectively) in 50 years if conditions remain unchanged. More positively, 

models for the LaHave River show that a 20 percent increase in habitat quality can reverse the risk 

of extirpation risk from 87 percent in 50 years to 21 percent. Liming, the addition of buffering 

materials to a freshwater system, is a common method of increasing pH of acidified streams. 

Similarly, terrestrial liming is the addition of buffering materials to the catchments, or drainage 

basins, of the acidified river. The advantages of terrestrial liming is that it addresses the problem 

directly and can have a long term effect after a small number of applications, if done correctly. The 

effectiveness of terrestrial liming in SWNS is currently being researched and may be a promising 

method to improve water quality in the area. The decision on where to lime and how much to lime 

is crucial to the success of terrestrial liming in increasing pH and helping support the SU Atlantic 

salmon. When selecting sites to lime considerations need to be made for attributes supporting an 

increasing in pH as well as the ability for a site to support a self-sustaining SU population. There 

is a need for a comprehensive study identifying candidate terrestrial liming sites in SWNS. My 

research will meet this need through a comprehensive Geographic Information System (GIS) 

analysis of potential sites and the prioritization of these sites using a decision-based model and site 

scoring methods.

1

Marley Geddes, Honors Undergraduate Student, Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada B3H 4R2

Shannon Sterling, Assistant Professor, Department of Earth Sciences, Dalhousie University, Halifax, NS, Canada B3H 4R2
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 295

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

DEVELOPMENT OF A MERCURY LOAD MODEL USING TOPMODEL 

FLOW SIMULATIONS AT McTIER CREEK, SOUTH CAROLINA

Stephen T. Benedict, Paul A. Conrads, Toby D. Feaster, Celeste A. Journey, 

Heather E. Golden, Christopher D. Knightes, Gary M. Davis, Paul M. Bradley1

McTier Creek is a small watershed located in Aiken County, South Carolina and forms part of 

the headwaters for the Edisto River basin. The Edisto River basin is noted for having some of the 

highest measured fish-tissue mercury concentrations in the United States. In an attempt to improve 

the understanding of the factors causing these high mercury levels, the National Water-Quality 

Assessment Program of the U.S. Geological Survey conducted an extensive field investigation of 

mercury in the McTier Creek ecosystem. This investigation included the collection of hydrologic, 

biologic, and water-quality data as well as the development of a number of hydrologic and waterquality models. One modeling effort involved the development of a simple water-quality load 

model that utilized a mass-balance equation in conjunction with hydrologic simulations from the 

topography-based hydrological model (TOPMODEL). Several variants of this load model were 

developed including one, called TOPLOAD, which utilized the simulated surface and subsurface 

flow components taken directly from TOPMODEL. A second variant, TOPLOAD-H, added a 

groundwater partitioning algorithm to TOPMODEL, thereby providing for multiple groundwater 

flow components. A brief description of the development of these simple mercury load models and 

results of the simulation in the McTier Creek basin will be presented.

1

Stephen T. Benedict, Hydrologist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29036

Paul A. Conrads, Surface Water Specialist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29036

Toby D. Feaster, Hydrologist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29036

Celeste A. Journey, Water Quality Specialist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29036

Heather E. Golden, Research Physical Scientist, US Environmental Protection Agency, Office of Research and Development, Ecological Exposure 

Research Division, Cincinnati, OH 45268

Christopher D. Knightes, Environmental Engineer, US Environmental Protection Agency, Athens, GA 30605

Gary M. Davis, Environmental Engineer, US Environmental Protection Agency, Office of Research and Development, Ecosystems Research Division, 

Athens, GA 30605

Paul M. Bradley, Hydrologist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29036
296 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

SIMULATION OF STREAMFLOW IN THE McTIER CREEK 

WATERSHED, SOUTH CAROLINA

Toby D. Feaster, Heather E. Golden, Paul A. Conrads, Paul M. Bradley1

The McTier Creek watershed is located in the Sand Hills ecoregion of South Carolina and is a 

small catchment within the Edisto River basin. Two watershed hydrology models were applied to 

the McTier Creek watershed as part of a larger scientific investigation to expand the understanding 

of relations among hydrologic, geochemical, and ecological processes that affect fish-tissue 

mercury concentrations within the Edisto River basin. The two models are the topography-based 

hydrological model (TOPMODEL) and the grid-based mercury model (GBMM). TOPMODEL 

uses the variable-source area concept for simulating streamflow, and GBMM uses a spatially 

explicit modified curve-number approach for simulating streamflow. The hydrologic output from 

TOPMODEL can be used explicitly to simulate the transport of mercury in separate applications, 

whereas the hydrology output from GBMM is used implicitly in the simulation of mercury fate 

and transport in GBMM. The modeling efforts were a collaboration between the U.S. Geological 

Survey and the U.S. Environmental Protection Agency, National Exposure Research Laboratory.

1

Toby D. Feaster, Hydrologist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29036

Heather E. Golden, Research Physical Scientist, US Environmental Protection Agency, Office of Research and Development, Ecological Exposure 

Research Division, Cincinnati, OH 45268

Paul A. Conrads, Surface Water Specialist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29036

Paul M. Bradley, Hydrologist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29036
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 297

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

DEVELOPING THE U.S. GEOLOGICAL SURVEY STREAMSTATS 

WEB APPLICATION FOR SOUTH CAROLINA

Toby D. Feaster, Jimmy M. Clark1

Government agencies, engineers, scientists, water-resources managers, and others use streamflow 

statistics for the purposes of water management, permitting, and infrastructure design. Examples 

of such streamflow statistics are the 1-percent chance flood (also referred to as the 100-year 

flood), the mean annual flow, and the annual minimum 7-day average streamflow with a 10-year 

recurrence interval. These statistics can be computed for locations where streamflow data are 

collected, such as at U.S. Geological Survey (USGS) streamgages. However, financial and humanresource limitations make it impossible to collect data everywhere streamflow statistics may be 

needed, which are often are ungaged locations where no streamflow data are available. 

To address the needs of entities requiring streamflow information, the USGS, in cooperation 

with Environmental Systems Research Institute, Inc., developed a web-based application called 

StreamStats that serves published streamflow statistics to the public and facilitates the estimation 

of streamflow statistics for ungaged sites on streams (http://water.usgs.gov/osw/streamstats/index.

html). StreamStats is an integrated web-based geographic information system (GIS) application 

that makes the process of computing streamflow statistics for ungaged sites faster, more accurate, 

and more consistent than previous methods.

StreamStats allows a user to select any point on a stream through a web-based interactive map and 

delineate the contributing drainage area to that point. Once the user confirms the basin boundary, 

StreamStats identifies any regional USGS equations that are available for the basin, computes the 

required basin characteristics, and uses them in the equations needed to compute the streamflow 

statistics. Additionally, a report containing the computed basin-characteristic values and 

streamflow statistics is generated. StreamStats also provides an option to download a shapefile of 

the drainage boundary that can be imported into a local GIS. The shapefile includes the computed 

basin characteristics and streamflow statistics as attributes.

In October 2014, the USGS, in cooperation with the South Carolina Department of Transportation, 

began an investigation to develop and implement the StreamStats web application in South 

Carolina. When completed, the application will include regression equations to estimate floodfrequency flows at rural and urban ungaged locations along with the basin characteristics needed 

to compute those estimates. The StreamStats database also will include low-flow frequency 

statistics published by the USGS. Additionally, field measurements of historic bridge scour in 

South Carolina and USGS historic indirect flow measurements will be incorporated into the South 

Carolina StreamStats application. It is anticipated that the project will be completed by April 2018.

1

Toby D. Feaster, Hydrologist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29036

Jimmy M. Clark, Hydrologist, US Geological Survey, South Carolina Water Science Center, Columbia, SC 29036
298 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

USE OF BENEFICIAL BACTERIA TO TREAT 

NUTRIENTS IN POND WATER

Mike Haberland, Salvatore Mangiafico, Debra Haberland1

Agriculture and urban ponds often suffer impaired water quality from high levels of nitrogen 

and/or phosphorous that typically triggers excessive “blooms” of algae or cyanobacteria. 

These blooms can lead to extremely low dissolved oxygen levels leading to fish kills, fouling 

of irrigation equipment, smothering of native vegetation, health and odor nuisance from rotting 

organic matter, loss of recreational or commercial value and general unsightliness. Bacteria are 

known to breakdown nitrogen and phosphorous and ammonia in controlled wastewater treatment 

plant processes. Based on this information, commercial enterprises market beneficial bacteria 

products scaled for application to reduce nutrient levels in eutrophic ponds. This project tested 

a beneficial bacteria product to determine its effectiveness to reduce high phosphorous levels in 

a controlled pond water experiment. The bacteria in the tested product were: 2-Bacillus subtilis, 

2-B. amyloliquefaciens, B. pumilis, B. licheniformis, and B. megatarium. We compared three 

treatments of pond water, versus three treatments of pond water with beneficial bacteria added. 

All treatment water was filtered to 5 μm. All treatments were supplied with air to keep the water 

aerated, mixed, and to encourage microbiological activity. Samples were collected weekly for 

three weeks. A second set of treatments was also compared, but no supplemental air was added. 

Sample parameters included DO, temperature, pH, conductivity, and orthophosphate (soluble 

phosphorous). The orthophosphorous values were analyzed using a LaMotte Smart3 Colorimeter. 

All the 190 L treatment containers were maintained at ambient pond water temperature and light 

conditions by floating them in the pond. A raw pond water sample was collected each week 

and compared to the treatments. Results showed no significant difference in orthophosphorous 

reduction across all treatments with the addition of the beneficial bacteria. 

1

Mike Haberland, Environmental and Resource Management Agent, Rutgers Cooperative Extension of Burlington and Camden Counties, 

Cherry Hill, NJ 08002

Salvatore Mangiafico, Environmental and Resource Management Agent, Rutgers Cooperative Extension of Salem & Cumberland Counties, 

Woodstown, NJ 08098

Debra Haberland, Field Assistant, Rutgers Cooperative Extension of Burlington and Camden Counties, Cherry Hill, NJ 08002
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 299

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

INVESTIGATION OF CO2 AND CH4 EMISSIONS FROM TIDAL 

FRESHWATER AND NON-TIDAL BOTTOMLAND FOREST 

RIPARIAN ZONES

Bryan Farley, Carl Trettin, Craig Allan1

Tidal bottomland hardwood forests and wetlands are found throughout the Southeastern Atlantic 

Lower Coastal Plain due to its low topographic gradient and is characterized by a complex 

network of drainage systems that intertwine with mesotidal estuaries and freshwater tidal systems. 

Wetlands are an important source of greenhouse gases including CO2 and CH4 and need to be 

considered in any future climate-modeling scenarios. The production of CH4 and CO2 in wetlands 

is the result of a complex suite of microbial activities that include interactions that both enhance 

and inhibit competition for key organic substrates. The Santee Experimental Forest is a 6,100 

acre-research facility located within the Francis Marion National Forest, SC and is situated 

within the Huger Creek watershed in the headwaters of the East Branch of the Cooper River. 

Historical rice cultivation in the Santee Experimental Forest has resulted in a series of relic berms 

and drainage ditches that are superimposed on a complex microtopography consisting of natural 

hummocks and hollows. This project seeks to determine whether tidal bottomland hardwood 

forests are functionally different from non-tidal bottomland hardwood forests. The project will 

investigate environmental variables such as water table position and periodicity, soil temperature, 

soil moisture level, soil redox conditions, decomposition rates, organic matter content, grain size, 

porosity, and density in both tidal and non-tidal sites. Additionally, the project will investigate 

how the wetland hydroperiodicity and complex microtopography affects CO2 and CH4 emissions. 

The seasonal CO2 and CH4 emissions from tidal, transitional, and non-tidal bottomland hardwood 

forests will be measured with a monthly sampling regime to determine if there are differences in 

the emission rates along the longitudinal tidal to non-tidal gradient. A spatially and temporally 

extensive series of measurements will be taken in the dormant and growing seasons to measure 

spatial differences in emission rates across the floodplain and temporal differences over a series of 

complete diurnal cycles.

1

Bryan Farley, Graduate Student, Department of Geography and Earth Sciences, UNC Charlotte, Charlotte, NC 28037

Carl Trettin, Research Soil Scientist, Center for Forested Wetlands Research, USDA Forest Service, Cordesville, SC 29434

Craig Allan, Professor and Chair, Department of Geography and Earth Sciences, UNC Charlotte, Charlotte, NC 28037
300 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

IMPACT OF OFF-HIGHWAY VEHICULAR TRAIL SYSTEM 

ON WATER QUALITY

Stephanie Laseter, Chelcy Miniat, Randy Fowler, 

Dick Rightmyer, Ed Hunter1

To quantify the impact of an off-highway vehicle (OHV) trail system on water quality we used a 

paired-watershed approach to compare a treatment site (watershed containing OHV trail system) 

to a reference watershed with similar area, topography, elevation, land cover, management history 

and slope. The Locust Stake OHV trail system is located in Habersham County, GA on the North 

Fork of the Broad River (managed by the USDA Forest Serivice Chattooga River Ranger District). 

The trail system encompasses 11 sections which were designated for OHV use in the mid-80s and 

were operational until January 2012. The system was closed in 2012 and a trail assessment was 

completed. Following the Assessment, the USFS installed a series of silt fences to limit erosion 

and barriers to prevent further use of individual trail sections. One trail was closed permanently. 

We deployed automated water samplers (Sigma,Inc) in treatment and reference watersheds to 

collect flow proportional samples. Samplers were programmed to collect water samples during 

heavy rain events when expected sediment transport rates to be at their maximum. Sites were 

also instrumented with an ISCO sonde to measure turbidity in-stream at the same location. 

Water samples were analyzed for total suspended solids (TSS) at the Coweeta Hydrologic Lab. 

Concurrent observations between the reference and treatment watersheds were modeled over time, 

with intervention terms to designate levels of OHV use. We report the results of weekly TSS, 

turbidity, streamflow and trail use since late 2013. Land managers need science-based information 

on the impact that OHV trail use has on stream water quality to make decisions on managing 

forests for recreation.

1

Stephanie Laseter, Hydrologist, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA Forest 

Service, Otto, NC 28763

Chelcy Miniat, Research Project Leader, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA 

Forest Service, Otto, NC 28763 

Randy Fowler, Biological Scientist, Coweeta Hydrologic Laboratory, Center for Forest Watershed Research, Southern Research Station, USDA Forest 

Service, Otto, NC 28763

Dick Rightmyer, Soil Scientist, Southern Region Chattahoochee-Oconee National Forest, Chattooga River Ranger District, USDA Forest Service, 

Gainesville, GA 30501

Ed Hunter, District Ranger, Southern Region Chattahoochee-Oconee National Forest, Chattooga River Ranger District, USDA Forest Service, 

Lakemont, GA 30552
Proceedings of the Fifth Interagency Conference on Research in the Watersheds 301

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

THE AGRICULTURAL CONSERVATION PLANNING FRAMEWORK: 

A GIS-BASED TOOLBOX TO FACILITATE WATERSHED PLANNING 

AT THE HUC12 SCALE

M.D. Tomer, S.A. Porter, D.E. James, and K.J. Cole1

Investments in agricultural conservation are most effective if practices are located where 

measurable improvements in water quality are likely to result. Methods are available to map where 

some conservation practices should effectively improve water quality, but these methods have 

not yet been brought into a common framework to assist watershed planning. The Agricultural 

Conservation Planning Framework (ACPF) has been developed to apply precision conservation 

techniques in HUC12 watersheds, emphasizing practices suited to Midwestern agriculture and 

application of terrain analysis to high-resolution digital elevation models derived from LiDAR 

(Light Detection And Ranging) survey data. We have combined a suite of analyses that identify 

where a variety of conservation practices can be placed to intercept and treat water where it moves 

and accumulates on the landscape into an ArcGIS toolbox. The approach classifies practices by 

their relative placement (i.e., in-field, below-field, or riparian zone) and flow pathway addressed 

(surface runoff or subsurface tile drainage). Utilities are included to identify fields most prone to 

deliver runoff to streams, and a riparian classification scheme provides a simple but functional 

method to map buffer opportunities throughout the stream corridor. The framework can be 

applied to provide multiple scenarios with combinations of practices that can be evaluated using 

stakeholder feedback. A spreadsheet tool to compare planning scenarios in terms of potential 

nutrient reduction and land area required for implementation has also been developed. A key 

advantage of this approach is that it provides a non-prescriptive but landscape-specific resource for 

local communities to engage in watershed planning at the HUC12 scale. Required input data are 

widely available, enabling application in many watersheds at relatively little cost.

1

M.D. Tomer, Research Soil Scientist, USDA Agricultural Research Service, National Laboratory for Agriculture and the Environment, 

Ames, IA 50011

S.A. Porter, Physical Science Technician, USDA Agricultural Research Service, National Laboratory for Agriculture and the Environment, 

Ames, IA 50011

D.E. James, Geographic Information Specialist, USDA Agricultural Research Service, National Laboratory for Agriculture and the Environment, 

Ames, IA 50011

K.J. Cole, Watershed Specialist, USDA Agricultural Research Service, National Laboratory for Agriculture and the Environment, Ames, IA 50011
302 Headwaters to Estuaries: Advances in Watershed Science and Management

Poster Session

Citation for proceedings: Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in watershed science 

and management—Proceedings of the Fifth Interagency Conference on Research in the Watersheds. March 2-5, 2015, North Charleston, South 

Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

CULVERT DESIGN AND TIDAL MARSH HEALTH

Jaclyn Daly-Fuchs, Clayton Willis, Pace Wilber1

Roads constructed through salt marsh can restrict tidal flow and fish passage if culverts are not 

adequately sized, designed, and maintained. The implications for restricted marsh hydrology 

include degraded water quality, nekton use, and vegetation growth. Numerous roadways 

throughout the Charleston area bisect tidal marshes. We examined 18 marsh sites where culverts 

were embedded into the roadway to determine if hydrology, vegetation, and fish passage were 

impaired. We then compared culvert size, shape, and elevation to tidal features such as wetland 

and creek width to develop guidance on culvert design standards for restoration or new roadway 

projects.

1

Jaclyn Daly-Fuchs, Fishery Biologist, Habitat Conservation Division, NOAA, National Marine Fisheries Service, Charleston, SC 29412

Clayton Willis, Fishery Biologist Intern, Habitat Conservation Division, NOAA, National Marine Fisheries Service, Charleston, SC 29412

Pace Wilber, Supervisory Fish Biologist, Habitat Conservation Division, NOAA, National Marine Fisheries Service, Charleston, SC 29412
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Stringer, Christina E.; Krauss, Ken W.; Latimer, James S., eds. 2016. Headwaters to estuaries: advances in 

watershed science and management—Proceedings of the Fifth Interagency Conference on Research in the 

Watersheds. March 2-5, 2015, North Charleston, South Carolina. e-Gen. Tech. Rep. SRS-211. Asheville, 

NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 302 p.

These proceedings contain the abstracts, manuscripts, and posters of presentations given at the Fifth 

Interagency Conference on Research in the Watersheds—Headwaters to estuaries: advances in watershed 

science and management, held at the Trident Technical College Conference Center in North Charleston, 

South Carolina, March 3-5, 2015. The conference was hosted by the USDA Forest Service, Southern 

Research Station, Center for Forested Wetlands Research.

The conference theme was selected to recognize the focus of many natural resource agencies and universities 

in understanding how ecosystems are connected from interior upland habitats to the estuaries, as land use in 

the upper portion of watersheds often affect hydrological, ecological, and sociological processes downstream. 

This theme builds on past ICRW programs held in Arizona, North Carolina, Colorado, and Alaska by 

delivering a strong southeastern coastal plain theme while maintaining a broad national focus that highlights 

ongoing interagency research and management initiatives.

The conference was structured to focus on key issues faced by managers and scientists throughout the US, 

with many of these issues having a strong coastal watershed focus. Thematic areas included managing 

forested wetlands and agricultural catchments, identifying research advances from experimental watersheds, 

tracking the fate of contaminants through landscapes, advancing restoration ecology of connected 

ecosystems, and understanding the role of climatic perturbations (e.g., drought, severe storms) on watersheds. 

In addition, the role that ecosystems play in water use and management was a focal point, including modeling 

and measuring evapotranspiration associated with land use change.

Keywords: Coastal plain, forest hydrology, land use, watershed science.