Five Hydrologic Studies

Conducted by or in Cooperation 

with the Center for Forested 

Wetlands Research, 

U.S. Department of Agriculture 

Forest Service

D.M. Amatya, C.C. Trettin, R.W. Skaggs, 

M.K. Burke, T.J. Callahan, G. Sun, J.E. Nettles, 

J.E. Parsons, and M. Miwa

United States

Department of

Agriculture

Forest Service

Southern 

Research Station

Research Paper

SRS–40
December 2005

Southern Research Station

P.O. Box 2680

Asheville, NC 28802

DISCLAIMER

The use of trade or firm names in this publication is for reader information and does not imply endorsement 

of any product or service by the U.S. Department of Agriculture or other organizations represented here.

D.M. Amatya, Research Hydrologist, and C.C. Trettin, Project Leader, 

USDA Forest Service, Center for Forested Wetlands Research, 

Charleston, SC 29414; R.W. Skaggs, William Neal Reynolds and 

Distinguished University Professor, North Carolina State University, 

Raleigh, NC 27695; M.K. Burke, Research Ecologist, USDA Forest 

Service, Center for Forested Wetlands Research, Charleston, SC 29414; 

T.J. Callahan, Assistant Professor, College of Charleston, Charleston, 

SC 29424; G. Sun, Research Hydrologist, USDA Forest Service, 

Southern Global Change Program, Raleigh, NC 27606; J.E. Nettles, 

Research Hydrologist, Weyerhaeuser Company, Columbus, MS 39704; 

J.E. Parsons, Professor (now deceased), North Carolina State 

University, Raleigh, NC 27695; M. Miwa, Research Hydrologist, 

International Paper Company, Bainbridge, GA 39819.

The Authors
i

Five Hydrologic Studies Conducted

by or in Cooperation with the

Center for Forested Wetlands Research,

U.S. Department of Agriculture Forest Service

D.M. Amatya, C.C. Trettin, R.W. Skaggs, M.K. Burke,

T.J. Callahan, G. Sun, J.E. Nettles, J.E. Parsons, and M. Miwa
ii
iii

Contents

Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Long-Term Studies on Naturally Drained Watersheds at Santee Experimental Forest,

South Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

 Site Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

 Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

 Results to Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

 Next Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Long-Term Studies on Managed Pine Forest at Carteret County, North Carolina . . . . . . . . . . . 6

 Site Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

 Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

 Results to Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

 Next Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

The Coosawhatchie Bottomland Ecosystem Study, South Carolina . . . . . . . . . . . . . . . . . . . . . . . 11

 Site Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

 Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

 Results to Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

 Next Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Study on High-Intensity Short-Rotation Woody Crop Site at Trice Farm, South Carolina . . . . 14

 Study Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

 Results to Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

 Next Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Study of Depressional Isolated Wetlands (Carolina Bays) at Burch Fiber Farm,

South Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

 Site Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

 Results to Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

 Next Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Summary and Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
iv


Five Hydrologic Studies

Conducted by or in Cooperation with the Center for 

Forested Wetlands Research, U.S. Department of Agriculture 

Forest Service

D.M. Amatya, C.C. Trettin, R.W. Skaggs, M.K. Burke, T.J. Callahan, G. Sun, 

J.E. Nettles, J.E. Parsons, and M. Miwa

Abstract

The U.S. Department of Agriculture Forest Service Center for Forested 

Wetlands Research has conducted or cooperated in studies designed to 

improve understanding of fundamental hydrologic and biogeochemical 

processes that link aquatic and terrestrial ecosystems. Five of these studies 

are discussed here. The first is based on observations made on long-term 

experimental watersheds established in the 1960s on the Forest Service 

Santee Experimental Forest in South Carolina. It quantifies the soil moisture

dynamics, flow regimes, and water chemistry of low-gradient forested 

wetlands. The second study is being conducted in cooperation with North 

Carolina State University. It is a long-term project aimed at quantifying the 

effects of various water management and silvicultural management practices

on hydrology and water quality at the Weyerhaeuser Company’s managed 

pine forest in Carteret County, North Carolina. The third study is a long-term

ecosystem study on MeadWestvaco’s Coosawhatchie River bottomland hardwood site in South Carolina. It addresses questions related to public concerns

about the need for protection, restoration, and sustainable management of 

forested wetlands. The fourth study, which was conducted between 1997 and

2000, examined the hydrology and water quality of intensively managed

short-rotation woody crop plantations on International Paper’s Trice experimental forest in the upper Coastal Plain of South Carolina. A fifth study was

conducted between 1996 and 2004 at MeadWestvaco’s Carolina bay site in 

the South Carolina upper Coastal Plain; it assessed the surface-water and 

ground-water interactions between Carolina bays and their surrounding 

uplands. Recommendations are provided for using knowledge gained 

through these and other studies as a basis for expanding needed hydrologic 

research with collaborators to address four major areas of water-related 

issues in the Southeast.

Keywords. Forested wetlands, management impacts, models, vegetation, 

water management, water quality, watershed.

Introduction

Managing forested wetland landscapes to improve water 

quality, water quantity, and productivity requires a detailed 

understanding of functional linkages between ecohydrologic 

processes and management practices, which in turn requires 

an accurate understanding of landscape hydrologic and 

nutrient cycling processes. Watershed-level hydrologic and 

nutrient cycling processes are complicated by the presence 

of varied land features such as forests, wetlands, riparian 

buffers, uplands, and water bodies, and multiple land uses 

increase this complexity still further. Scientists recognize that

long-term ecohydrologic monitoring of watersheds is necessary if they are to understand the basic physical processes of 

natural and anthropogenic disturbance and the impact of management practices on these processes. Long-term monitoring 

provides baseline data for assessing this impact, conservation

of regional ecosystems, generation of scientific hypotheses, 

and testing of hydrologic and water-quality models. The 

Southern Forest Resource Assessment (Wear and Greis 2002)

emphasized that there is a need for research that will enable 

us to predict the long-term cumulative nonpoint-source 

impacts of silvicultural activities on water quality and 

overall watershed health. 

To understand the ecohydrologic role of forested wetlands in 

a landscape, it is necessary to develop water and nutrient 

budgets and to quantify the long-term hydroperiod dynamics 

of those wetlands. Long-term hydrologic data from small, 

paired, forested watersheds at Coweeta Hydrologic Laboratory

in North Carolina (NC) provide basic understanding of ecohydrologic processes for regional upland watersheds (Swank 

and others 2001). Tajchman and others (1997) report the 

water and energy balance of a 39-ha central Appalachian 

watershed with forest cover of 80-year-old upland oaks and 

cove hardwoods using 40 years of hydrologic data. However,

only a few such observational studies have been done for

the forested landscapes of the lowlands of the Southeastern 

Coastal Plain. These landscapes consist of natural and managed forests, depressional wetlands, pine flatwoods, riparian 

buffers, and bottomland hardwoods on brackish waters. 

They are characterized by poorly drained high-water-table 

soils, wet sites, and low topographic relief. Some of these 

wetlands have been drained artificially to lower water tables 

for trafficability and reduction of excessive moisture for 

increased crop growth. Hillslope processes dominate the 

hydrology of upland watersheds, but hydrologic processes 

on relatively low-gradient, poorly drained Coastal Plain sites 
are usually dominated by shallow water-table positions. Most

of the outflows (surface runoff and subsurface drainage) from

these watersheds in fact drain from saturated areas where the 

water is at the surface or a shallow water table is present. This

means that total outflow depends on the frequency and duration of flooding and on the dynamics of the water table 

(hydroperiod), which are driven by rainfall and evapotranspiration (ET). Although potential ET is primarily controlled 

by solar energy, ET is also dependent on soil type, vegetation

type, and seasonal dynamics. This complicates the task of 

quantifying the water budget components of these wetland 

systems, and the need to account for the use of various water 

and silvicultural management practices and interactions with 

surrounding uplands makes the job even more challenging. 

Only a few studies have documented hydrology and water 

budgets for depressional wetlands, bottomland hardwoods, 

pine flatwoods, pocosins, and pine plantations and their interactions with surrounding uplands (Amatya and others 1996, 

1997; Burke and Eisenbies 2000; McCarthy and others 1991;

Pyzoha 2003; Riekerk and others 1979; Skaggs and others 

1990; Sun and others 2000a; Young 19681; Young and 

Klaiwitter 1968). 

In the last two decades, there has been growing concern over 

the impact of both human activities (forest management, land

use conversion, agriculture, and urbanization) and natural 

disturbances (droughts, fire, floods, and hurricanes) on the 

hydrologic, nutrient cycling, and export processes of forested

wetlands. The extent of commercial forestry operations is 

predicted to increase in the South over the next 20 years 

(Wear and Greis 2002), and this expectation increases the 

need to document the impact of silviculture on water quality 

in order to satisfy the public’s desire to maintain high-quality

water sources and industry’s commitment to water-quality 

precepts under the Sustainable Forestry Initiative. Silvicultural practices include harvesting, site preparation, bedding, 

fertilization, regeneration, and thinning. Timber harvesting 

reduces ET, thus elevating the ground-water level (Grace 

and others 2003, Sun and others 2000b, Xu and others 2002) 

and increasing the water yield from a forested site until the 

canopy is regenerated. These increases in water volume can 

change both storm and base flow, and without proper management of both volume and flow rate, may increase flow energy

throughout the harvested watershed. High-energy water can 

move farther, transport more sediment and nutrients to downstream water bodies, and even affect the sensitive brackish 

habitats essential for juvenile development of many marine 

fish and shellfish species. However, studies in NC have shown

that controlled drainage can be used to manage the highest 

energy runoff at hydrograph peaks, reducing nutrient and 

sediment loads in water from intensively managed pine plantations on poorly drained soils. Other studies have shown that 

riparian buffers provide similar impact reduction (Dissmeyer 

1994, NCASI 1994, Wynn and others 2000). However, additional studies are needed, especially concerning the waterquality effects of increasingly intensive forest management 

treatments (Wear and Greis 2002).

Recent studies document some effects of silvicultural practices on soil properties, hydrology, and water quality in the 

poorly drained lowlands of the Atlantic Coastal Plain (Amatya

and others 1997, Blanton and others 1998, Crawford and 

others 1992, Grace and others 2003, Lebo and Herrmann 

1998, Riekerk 1989, Sun and others 2001, Swindel and 

others 1982, Ursic 1991, Xu and others 2002). Shepard (1994)

reviewed studies quantifying the effects of silvicultural practices on the quality of water from nine wetland forest sites 

and found that harvesting timber raised nutrient concentrations above “natural” level for 1 to 4 years after harvest. Sun 

and others (2001) in their synthesis study of effects of timber

management on wetland forests reported that the hydrologic 

effects of various forest management practices across the 

Southern United States are variable, but generally minor, 

especially when forest best management practices are adopted.

The authors suggested that in addition to soils, wetland 

types, and management options, climate is an important 

factor controlling hydrology and magnitude of disturbance.

Chescheir and others (2003) reported the baseline outflow 

and nutrient characteristics of pine forest watersheds in NC. 

Recently, researchers have been investigating the use of 

short-rotation woody crop (SRWC) methods to produce 

hardwoods in the Southeast. There has been only limited 

study of the effects of SRWC forestry on hydrology and 

water quality. 

Data from various forested ecosystems are essential for 

developing and testing models that can be used to evaluate 

the effects of new management practices, climate change, 

and landscape processes at spatial and temporal scales at 

which monitoring is impractical (Amatya and Skaggs 2001; 

Amatya and others 2003a; McCarthy and Skaggs 1992; 

McCarthy and others 1992; Sun and others 1998a, 1998b). 

However, few existing models are properly applicable to 

address the complex processes of the low-gradient coastal 

forests at field or watershed scales.

The main objective of this paper is to provide an overview of

five major experimental studies that have been or are being 

conducted by the U.S. Department of Agriculture Forest 

Service (Forest Service) Center for Forested Wetlands 

1 Young, C.E., Jr. 1968. Water balance of a forested coastal plain watershed 

on the Santee Experimental Forest. Unpublished Progress Report, Study

W-2. On file with: USDA Forest Service, Southern Research Station, 

Center for Forested Wetlands Research, 2730 Savannah Highway, 

Charleston, SC 29414. 
Research (CFWR) at Charleston, SC (http://www.srs.fs.usda.

gov/charleston/), in collaboration with various area institutions, forest industries, and other agencies. These studies 

employ scientific monitoring and modeling approaches to 

address issues discussed above. The studies are (1) long-term

studies conducted at first-order headwater streams at Santee 

Experimental Forest, South Carolina (SC); (2) long-term 

studies conducted in managed (drained) pine forest at Carteret

County, NC; (3) the long-term Coosawhatchie Bottomland 

Ecosystem Study (CBES) in SC; (4) an experimental study 

on a high-intensity SRWC site at Trice Farm, SC; and (5) an 

experimental study of depressional wetlands and their interactions with uplands at Burch Fiber Farm, SC. For each 

study, the overview includes the site description, methodology, results to date, and next steps recommended or being 

planned. The paper concludes with recommendations for new

ecohydrologic studies to address the important scientific 

questions and management challenges in the forested 

wetlands of the Southeast. 

Long-Term Studies on Naturally Drained 

Watersheds at Santee Experimental 

Forest, South Carolina

Site Description

This naturally drained site is located at latitude 33°N. and 

longitude 80°W. in the Santee Experimental Forest, which is 

part of Francis Marion National Forest near Charleston, SC 

(fig. 1, left). In 1963, the Forest Service designated a 160-ha 

experimental forested watershed (WS 77) at this location 

(fig. 1, right) as a site for studies of hydrologic processes, 

flooding pattern, water balance components (especially ET 

and drainage), and effects of management practices for the 

low-gradient, forested wetlands of the humid Coastal Plain. 

This is one of the paired watersheds (with 206-ha watershed, 

WS 80, established later in 1968) on the headwater stream 

draining to Turkey Creek on the lower Atlantic Coastal Plain 

(fig. 1, right). During 1964 to 1968 the Forest Service 

expanded the experimental study at this site by adding two 

larger watersheds to it. These additional watersheds are 

designated as WS 78 and WS 79. Watershed 78 has an area 

of about 5000 ha and is drained by a third-order stream, 

Turkey Creek (outlet in fig. 1, right, but full boundary not 

shown). Watershed 79 has 500 ha of drainage area on a 

second-order stream and contains both WS 77 and WS 80. 

The Center continues to maintain long-term hydrologic 

monitoring of WS 77, WS 79, and WS 80. Information 

about these watersheds is summarized in table 1. 

The study site of interest here (WS 77 and WS 80) is on a 

marine terrace of the Pleistocene epoch.2 The area has low 

relief with surface elevations ranging from 4.0 to 10.0 m 

above mean sea level. Loblolly pine (Pinus taeda L.), longleaf pine (Pinus palustris P. Mill.), cypress (Taxodium distichum L.), and sweetgum (Liquidambar styraciflua L.) are 

Figure 1—Left: locations of the five study sites. Right: two experimental watersheds at Santee Experimental Forest in coastal South Carolina.

2 Gartner, D.; Burke, M.K. 2001. Santee Experimental Watershed database. 

32 p. Unpublished report (Revised from April 29, 1999). On file with: 

USDA Forest Service, Southern Research Station, Center for Forested 

Wetlands Research, 2730 Savannah Highway, Charleston, SC 29414. 
dominant forest species in the watershed (Sun and others 

2000b). Watershed 77 (treatment) was salvage harvested 

soon after Hurricane Hugo in September 1989; WS 80 

(control) was not salvaged. Watershed 77 supports a naturally regenerated stand of pine trees and has recently had 

understory burning. Soils are primarily loams and strongly 

acid, infertile Aquults characterized by seasonally high 

water tables, argillic horizons at 1.5 m depth, and low base 

saturation (see footnote 2). The climate of the research area 

is humid subtropical with long hot summers and short mild 

winters (Sun and others 2000b). Mean annual precipitation 

is about 1350 mm with highest rainfall in July and August 

and lowest rainfall in November to April. Winter storms are 

generally of low intensity and long duration, and summer 

storms are generally of high intensity and short duration. 

Objectives

• To quantify the hydrologic processes, flow dynamics, and 

baseline water and nutrient budgets for forested watersheds draining Coastal Plain streams.

• To evaluate the effects of management on hydrology and 

water quality.

• To develop and test hydrologic models for these naturally 

drained coastal forests. These models will help explain 

interactions among soils, vegetation, and hydroperiods 

and will be useful in evaluating management and climatic 

impacts.

• To conduct long-term ecohydrological studies of coastal 

headwater forests. 

Table 1—Santee Experimental Forest watersheds 77, 78, 79, and 80: infrastructures, data collection, and research needs

 Condition 

Watershed Drainage Estab- Outlet of infra- Status of

number area lished design structure Associated data monitoring Needs

77 160 ha 1963 Compound Good Stage, soil moisture, Monitoring Analysis of 

(Treatment; V-weir water quality, continuing old data and 

first order, GW levels, (no data publications 

Fox Gully) meteorological station 1981-1989)

78 5000 ha 1964 Outlet in — Stage, velocity, Monitoring Digital 

(Turkey a dam flow rates discontinued processing 

Creek) in 1984 of old data, 

 resume 

 monitoring 

 of water 

 quantity and

 quality, 

 analysis and 

 publications

79 (second 500 ha 1965 V-weir Good Stage, water quality Monitoring Processing,

order, Fox and 3-box continuing data

Gully) culvert analysis,

 publications

80 (control) 206 ha 1969 Compound Good Stage, water quality, Monitoring Digitizing 

initially; V-weir GW levels, meteorologi- continuing 1992-95 

 160 ha cal station, throughfall (no data data, 

now 1981-1989) analysis of 

 old data and 

 publications

— = not applicable; GW = ground water.
Monitoring

Measurements of precipitation, weir-stage height for flow 

rates, water-quality parameters, water-table elevations, and 

weather data are being collected on WS 77, WS 79, and WS 

80 (fig. 1, right, and table 1) for quantifying water nutrient 

budgets, flow, and water table dynamics of these low-gradient

forested watersheds. Watershed 77 is gauged with a flowrecording station upstream of a compound V-notch weir that 

spans the stream. Watershed 80 has a stream-gauging station 

at the outlet. This station consists of a compound V-notch and

a flat concrete weir with a recording gauge inside a stilling 

well. The flow measurement structure on WS 79 is a recording

gauge upstream of a V-notch weir. There is a concrete box 

culvert on either side of this weir, and the bases of these 

culverts are at the same level as the top of the V-notch. Flow 

measurements on all three watersheds were interrupted 

between 1981 and 1984 and did not start again until after 

Hurricane Hugo in September 1989. Recording of flow data 

on the largest watershed, WS 78, was discontinued in 1984. 

Automatic ISCO-3210 flow data loggers were installed on 

WS 77 and WS 80 only in 1996. Flow data are missing for 

intermittent periods for all watersheds. Water tables were 

measured using manual wells at several locations in WS 77 

and WS 80 until 1995. One automatic recording well (WL 40)

was installed on WS 80 in late 1995, and two were installed 

on WS 77 at that time (table 1).

Meteorological data (daily maximum and minimum air 

temperatures and precipitation) have been collected since 

1964 at a station designated as Met-5, which is located on 

WS 77, and since 1976 at Met-25 on WS 80. A complete 

weather station measuring maximum and minimum air 

temperatures, humidity, solar radiation, wind speed, and 

wind direction was installed in 1996 at Santee Headquarters, 

which is within 4 km from the watersheds. Only air temperature data were available prior to 1996. Several rain gauges 

were installed initially within and around the large watershed (WS 78), but their use was discontinued later.

Long-term data for daily precipitation, air temperature, and 

streamflow from WS 77 and WS 80 are being made available

through HYDRO-DB, a Web-based data sharing and harvesting server hosted by Oregon State University and sponsored 

by the Forest Service and National Science Foundation’s 

Long-Term Ecological Research network. The site is located 

at http://www.fsl.orst.edu/climhy/hydrodb/, where hydroecological data from various participating sites are posted.

Results to Date 

• Young (1967): Excess water in the form of surface runoff 

and subsurface drainage did not appear to be a problem on 

WS 77. Baseflow from the watershed was undependable. 

Reliability of water balance ET varied depending on the 

temporal scale. Twenty percent of the annual rainfall, on 

average, became stormflow, depending on seasonal soil 

moisture storage.

• Binstock (1978): A prescribed winter burn did not significantly deplete or enrich mineral soil, or significantly 

increase concentrations of dissolved nutrients in the 

streamwater.

• Richter and others (1983, 1982) and Richter (1980): 

Hydrologic fluxes of nitrogen, phosphorus, sulfur, and 

basic cations from burned pine litter to ground water and 

streamwater are not likely to have appreciable effects on 

water quality in the Atlantic and Gulf Coastal Plain.

• Sun and others (2000b): Annual streamflow was 25 to 30 

percent of annual precipitation. However, simulations 

using the MRSWARM model showed stream outflow 

values as great as 50 percent depending on annual rainfall 

pattern. Salvage logging after Hurricane Hugo greatly 

increased annual streamflow on WS 77. 

• Binkley (2001): Some nutrient concentration data from 

these first-order watersheds was reported as part of a 

nationwide assessment of nitrogen and phosphorus concentrations in forested streams. Binkley reported that 

nitrogen and phosphorus concentrations were generally 

much lower for forest streams than for streams draining 

agricultural or urban land. 

• Miwa and others (2003): Headwater streamflow on these 

watersheds is highly responsive to rain events and is also 

influenced by vegetation and topography. Quantitative 

separation of baseflow is difficult in these flat coastal 

watersheds.

• Amatya and others (2003b): A test of DRAINMOD’s 

(Skaggs 1978) predictions of daily streamflows of WS 80 

was encouraging. Available data were employed, and 

model calibration was minimal. 

• Amatya and others (2003a): A 6-year hydrologic comparison study of naturally drained WS 80 and an artificially 

drained watershed in NC found a wide variation in annual 

outflows affected by water-table position, which depends 

on both rainfall and ET. Average annual rainfall was lower 

at the SC site, but the water table was shallower and outflows greater and more frequent there than at the NC site. 

Site-to-site differences in soil and vegetation types may 

have contributed to these differences.

Next Steps

• A study now underway will quantify the water budget of 

WS 80 (the control). Both monitoring of rainfall, throughfall, outflow, PET, and water-table depth and modeling are 
being employed. DRAINMOD will be tested further with 

measured field data on soil hydraulic properties and 

weather parameters. 

• Sun is testing the capability of a distributed hydrologic 

model called MIKE-SHE to predict the hydrology of WS 

80.

• Long-term flow data from the first-order watersheds are 

being used for preliminary analyses of baseline loading 

calculations for a Charleston Bay water-quality model 

being developed by Tetra-Tech, Inc. (Lu and others 2005).

• Tetra-Tech, Inc., is sampling event water quality at WS 79 

in connection with development of the Charleston Bay 

water-quality model. 

• Researchers are analyzing data on outflow concentrations 

of nutrients from control WS 80 and treatment WS 77 as a 

means of comparing the effects of natural regeneration 

and prescribed understory burning on WS 77.

• Researchers have recently resumed hydrologic monitoring 

of WS 78 and will evaluate streamflow dynamics there. 

This project is supported by the Forest Service Southern 

Research Station Challenge Cost-Share Program and the 

National Council for Air and Stream Improvement, Inc. 

(NCASI). The cooperators in this project are the College 

of Charleston, the U.S. Geological Survey, the Francis 

Marion National Forest, the University of Cracow, TetraTech, Inc., and the SC Department of Transportation. 

• Existing long-term flow data for WS 78 may be analyzed 

to compare that watershed’s water budget and flow dynamics with those of WS 79 and WS 80. 

• A DRAINMOD-based watershed-scale model (Amatya 

and others 1997, 2004a) for evaluating the effects of 

various management practices may be tested on WS 78.

Long-Term Studies on Managed Pine

Forest at Carteret County, North Carolina

Site Description

In early 1988, the Weyerhaeuser Company and N.C. State 

University (http://www.bae.ncsu.edu/soil_water/scarteret.

htm) initiated a long-term study designed to quantify potential impacts of silvicultural and water management practices 

on downstream hydrology and water quality at a site in 

Carteret County, NC. Since 2002, the Center has been collaborating with NC State University in this long-term study, 

which has been supported primarily by NCASI. The study 

site (figs. 1 and 2) is located at approximately latitude 

34°48’N. and longitude 76°42’W. and is owned and managed 

by Weyerhaeuser Company. The research site consists of 

three artificially drained experimental watersheds, each 

Forested

land

To State road Pumping station

N

Agricultural

land

Virginia

North Carolina

South

Carolina Carteret

study site

Watershed boundary

100 m D1

1 2 3

Collector ditch

Watershed outlet

600 m

Automatic rain gauge 

V-notch weir with continuous recorder

Water table wells

Lateral ditch

Roadside collector ditch

Watershed 1

Experimental plot

D1

1

Legend

1 2 3

D1

D2

4 5 6

D3

7 8 9

Figure 2—Location map and layout of experimental watersheds (D1, control; D2 and D3, treatment watersheds) at Carteret 

County, NC.
ditches for each watershed (not shown). The parameters 

being measured and the method and the frequency of measurements are presented in table 2. McCarthy and others 

(1991) carried out an interception study of the 14-year-old 

pine forest. McCarthy and others (1991) and Amatya and 

others (1996, 2000a) provide detailed descriptions of the site 

and measurements, including the history of the loblolly pine 

stand planted in 1974. Amatya and others (1998, 2003c) 

have documented details of procedures for laboratory waterquality sample analysis. The chronology of various site 

treatments is shown in table 3.

Results to Date

• Evapotranspiration was the dominant component of the 

water budget (~70 percent of annual rainfall) followed by 

drainage outflows (Amatya and others 1996, McCarthy 

and others 1991). Interception was estimated to be 15 

percent of the average annual rainfall. Lateral seepage 

amounted to nearly 4 percent of the total rainfall. Seasonal 

loss through ET was as much as 96 percent of the rainfall 

depending on the season.

• Controlled drainage consisting of a raised weir on a flashboard riser during the summer-fall period on treatment 

watershed D2 helped store the water in the soil profile for 

periods of high tree growth and ET (Amatya and others 

2000a). Controlled drainage with a raised weir during the 

spring on treatment watershed D3 also substantially reduced

freshwater outflows, minimizing offsite impacts on the 

downstream water quality of the estuarine ecosystem. 

Similarly, use of an orifice-weir at the outlet of treatment 

watershed D3 significantly reduced outflows compared to 

free drainage from control watershed D1 (Amatya and 

others 2003c).

• Water management with controlled drainage with a weir 

on D2 and D3 reduced the export of nitrogen, phosphorus, 

and sediment, primarily by reducing drainage outflows 

(Amatya and others 1998). Controlled drainage with an 

orifice-weir reduced the export of phosphorus and sediment, but despite the reduced outflows, nitrogen export 

did not decrease (Amatya and others 2003c).

• Blanton and others (1998) found that the 1995-96 harvesting, bedding, and site preparation for regeneration on treatment watershed D2 reduced drainable porosity in the top 

60 cm of the profile by approximately 50 percent, resulting

in a significant change in storm outflow hydrographs.

• Amatya and others (2004b) found that water-table elevations and water-quality parameters returned to baseline 

levels (levels observed in control watershed D1) approximately 6 years after planting of pine trees in 1997 for 

regeneration on treatment watershed D2. However, due to 

about 25 ha in size and planted to loblolly pine in 1974. The 

site is flat, located at an elevation of about 3 m a.m.s.l., and 

its soils have shallow water tables. The soil is a hydric series,

Deloss fine sandy loam (a fine-loamy mixed Thermic Typic 

Umbraquult). Each watershed is drained by four parallel 

lateral ditches, which are 1.4 to 1.8 m deep and spaced 100 m

apart. These drain to a roadside collector ditch, which ultimately drains to an estuary about 3 km downstream (fig. 2). 

Long-term average annual precipitation at the site is 1330 mm.

The climate is typical of the Atlantic Coastal Plain; summers 

are hot and humid, and tropical storms and hurricanes are 

common. 

Objectives

• To conduct long-term field studies of the effects of 

different

water management and silvicultural treatments on the 

hydrology and water quality of drained pine plantations in 

the Coastal Plain.

• To develop and test DRAINMOD-based and other related 

models as tools for predicting and evaluating hydrology, 

water quality, productivity, and climate change for the 

drained forested watersheds.

• To apply the results of field-scale research (both data and 

models) to assess cumulative impacts of alternative land 

uses and management practices on the hydrology and 

water quality of large coastal watersheds.

Monitoring

Data on hydrology and water quality and soil and vegetation 

parameters were collected from three experimental plots 

(each about 0.13 ha) in each watershed (fig. 2). Rainfall was 

measured with an automatic tipping bucket rain gauge with 

a data logger in an open area on the western side of each 

watershed. Air temperature, relative humidity, wind speed, 

and net radiation were measured continuously by an automatic weather station located at the center of the treatment 

watershed (D2). An adjustable-height 120° V-notched weir 

located in a water-level control structure at a depth nearly 

equal to that of the bottom of the outlet ditch was used to 

measure drainage outflow in each watershed. A water-level 

recorder and an automatic data logger were installed upstream

of each weir and measured water levels at 6-minute intervals.

An additional recorder was placed downstream from the weirs

(not shown) to determine whether weir submergence occurred

and to provide data that could be used to correct flows in 

case of submergence. In 1990, a pump was installed downstream from all three watersheds in the roadside collector 

ditch to prevent weir submergence during larger events. Watertable elevations were measured by a continuous water-level 

recorder at each of two locations midway between the lateral 
Table 2—Parameters being measured at the Carteret study site, North Carolina

Monitoring Remarks/ Measurement

Parameter Method of measurement Location interval Units datalogger period

Hydrology

Precipitation Automatic tipping bucket Open area Event mm OMNIDATA 1988-2000

Texas Electronic 2000 to date

Manual gauge Open area 2-3 weeks mm Standard 1988 to date

Outflow Continuous stage Outlet 12-min cm OMNIDATA 1988-2000

INFINITY 2001 to date

120° V-weir Outlet 12-min m3hr-1 Weir Equation 1988 to date

Water table Continuous well Midfield 1 hour cm OMNIDATA infinity 1988 to date

Manual well Transect 2-3 weeks cm 1988-1995

Soil moisture Various depths Midfield 3-4 weeks Neutron probe 1988-1994

Various depths Midfield 3-4 weeks TDR 1995 to date

Throughfall Manual troughs Midfield Event mm 1988-1990

Stemflow Plastic semi-tubes Midfield Event mm 1988-1989

Weathera

Air temperature Automatic and manual Half-hourly °C CAMPBELL 1988 to date

Relative humidity Automatic and manual Half-hourly % SCIENTIFIC 1988 to date

Wind speed Anemometer At the middle Half-hourly m sec-1 CR-21 (until 1997) 1988 to date

Wind direction Anemometer of watershed Half-hourly Degrees 1988 to date

Solar radiation Pyranometer D2 Half-hourly W m-2 CAMPBELL 1988 to date

Net radiation Net radiometer Half-hourly W m-2 SCIENTIFIC 1997 to date

Soil temperature Sensor Half-hourly °C CR-10X (from 1997 to date

Soil heat flux Heat flux plates Half-hourly W m-2 1997 to date 1999-2000

Water quality

NO3+NO2, NH4 Composite and grab Outlet Time

TKN, TP, PO4 samples proportional mg L-1 ISCO 1988 to date

TSS,

pH, turbidity Manual meters Outlet 2-3 weeks Various HYDROLAB 1988 to date

DO, temp

Cations, metals Composite and grab Outlet 2-3 weeks mg L-1 ISCO 1988-1994

Tree physiology

Height Measuring pole Midfield Yearly m 1988 to date

DBH Dendrometer band Midfield Yearly cm 1988 to date

Leaf Area Index Litterfall traps Midfield 3-4 weeks 1988-1994

Leaf Area Index Leaf area analyzer Midfield 4-6 weeks Li-COR (2000) 1995 to date

Stomatal Porometer Midfield 3-4 weeks moles Li-COR (1600) 1988-1994

conductance m-2s-1

a All weather data from 1988 to 1997 were measured on an hourly basis by a CR-21 Campbell Scientific weather station located about 800 m west of the

study site.
Table 3—Chronology of water and silvicultural treatments on three experimental forested watersheds at Carteret site, 

North Carolinaa

Watersheds

 Year D1 (24.7 ha) D2 (23.6 ha) D3 (26.7 ha) Management scenarios

1974 Study began

1987 Experiment or monitoring equipment installation All watersheds 13-year-old pines

1988 Testing of various weir levels on all three watersheds Monitoring began; all watersheds

for free drainage (calibration period) commercially thinned in October

1989 Testing of various weir levels on all three watersheds Fertilizer application and Hurricane 

for free drainage (calibration period) Hugo’s impact on weir submergence

1990 Free drainage Controlled drainage Controlled drainage Water management treatment for 

(control) (June-November) (March-June) tree growth (D2) and minimum 

 offsite impact (D3)

1991 Free drainage Controlled drainage Controlled drainage Water management treatment for 

(control) (June-November) (March-June) tree growth (D2) and minimum 

 offsite impact (D3)

1992 Free drainage Controlled drainage Controlled drainage Water management treatment for 

(control) (June-November) (March-June) tree growth (D2) and minimum 

 offsite impact (D3)

1993 Free drainage Controlled drainage Controlled drainage Water management treatment for 

(control) (June-November) (March-June) tree growth (D2) and minimum 

 offsite impact (D3)

1994 Free drainage Controlled drainage Controlled drainage Water management treatment for 

(control) (June-November) (March-June) tree growth (D2) and minimum 

 offsite impact (D3)

1995 Free drainage Harvested Orifice-weir outlet Silvicultural treatment (D2) and

(control) (June-July) water management (D3)

1996 Free drainage Site preparation/ Orifice-weir outlet Silvicultural treatment (D2) and

(control) bedding in October water management (D3)

1997 Free drainage Planted for regener- Orifice-weir outlet Silvicultural treatment (D2) and

(control) ation (February) water management (D3)

1998 Free drainage 1-year-old pine trees Orifice-weir outlet Silvicultural treatment (D2) and

(control) water management (D3)

1999 Free drainage 2-year-old pine trees Orifice-weir outlet Silvicultural treatment (D2) and

(control) water management (D3)

2000 Free drainage 3-year-old pine trees Back to free drainage Silvicultural treatment (D2) and

(control) (orifice removed February) water management (D3)

2001 Free drainage 4-year-old pine trees Free drainage Silvicultural treatment (D2) and

(control) water management (D3)

2002 Free drainage 5-year-old pine trees Thinned in June Silvicultural treatment on 

(control) D2 and D3

2003 Free drainage 6-year-old pine trees After thinning Silvicultural treatment on 

(control) D2 and D3

a Pine trees on all three watersheds (D1, D2, and D3) were planted in 1974 with a precommercial thinning in 1980 and fertilizer application in 1981 (after 

Amatya and others 1996). Most of these studies are being supported by NCASI, Inc.
10

frequent weir submergence on treatment watershed D2 

during large events, the results for the drainage outflows 

were somewhat inconclusive.

• On the basis of 100 site-years of outflow data for forested 

watersheds in the Coastal Plain of eastern NC, including 

the data from control watershed D1, Chescheir and others 

(2003) reported a median hydrologic response factor of 31

percent, with an interquartile range of 26 to 35 percent. 

For most study sites, nutrient concentrations in forest 

outflow were lower than typical values for other land uses. 

• Amatya and others (2003a) studied annual outflows from 

naturally drained watershed WS 80 in SC and artificially 

drained watershed D1 in NC. They found that annual 

outflows varied widely and were affected by water-table 

position, which is dependent upon both rainfall and ET. 

Naturally drained WS 80 in SC had much shallower 

water-table depths and more frequent outflows than did 

watershed D1, even though average annual rainfall was 

lower at the SC site. Site-to-site differences in soil and 

vegetation types may have contributed to this.

• Using data from control watershed D1 and many other 

sites in the Southern United States, Lu and others (2003) 

developed a long-term annual ET model with four independent variables: annual precipitation, latitude, elevation, 

and forest coverage. The model may be used to examine 

the spatial variability of water availability and effects of 

land use change on water availability. 

• Sun and others (2002) concluded that streamflows from 

flatwoods watersheds like the one at the Carteret site 

generally are discontinuous in more years than are streamflows from upland watersheds. The stormflow peaks in 

these low-gradient coastal watersheds were smaller than 

those in the upland watersheds except under extremely 

wet conditions. 

• Amatya and others (1995) used weather data from the 

Carteret site and two other coastal stations to evaluate five 

methods of estimating PET. The Penman-Monteith method

was employed as a reference. Amatya and others (2000b) 

studied the relationships between net and solar radiation 

for three vegetation canopies (emerging wetland vegetation at the Carteret site and grass and young pine trees 

elsewhere) in coastal NC.

• McCarthy and others (1992) used data from this study to 

develop and test the forest hydrologic model DRAINLOB,

which is based on DRAINMOD (Skaggs 1978). DRAINLOB was modified for use at the watershed scale (Amatya 

and others 1997) and was successfully applied to data for 

large coastal watersheds with pine forest cover (Amatya 

and others 1997, 2003d). 

• Data from this site were used to test the capability of 

DRAINLOB to model various water and silvicultural 

management practices. (Amatya and Skaggs 1997, 

McCarthy and Skaggs 1992, Richardson and McCarthy 

1994). The model was further tested with long-term data 

from the study site (Amatya and Skaggs 2001).

• Measured data and the DRAINLOB model modified for 

an orifice-weir outlet were used to develop preliminary 

guidelines for the design of an orifice-weir outlet for 

managing water and offsite impacts (Amatya and others 

1999). 

• Using a PnET-II ecosystem process model, Sun and others 

(2000c) predicted a significant increase of drainage (6 percent) and forest productivity (2.5 percent) for a pine forest 

on the control watershed in Carteret County, NC, as a 

result of future climate change scenarios predicted by the 

General Circulation Model HADCM2. 

• The study at the Carteret site, together with a large watershed-scale experimental study near Plymouth, NC, resulted

in a long-term database and hydrologic and water-quality 

models for evaluating the cumulative impacts of various 

agricultural and silvicultural management practices on a 

lower Coastal Plain watershed (Amatya and others 1997, 

2002, 2004a; Chescheir and others 1998; Fernandez and 

others 2002; Skaggs and others 2003). 

Next Steps

• A final study is underway to evaluate the hydrologic and 

water-quality impacts of harvesting and subsequent 

planting for regeneration on watershed D2.

• Similarly, monitoring is continuing to evaluate the hydrology and water-quality impacts of a second commercial 

thinning of mid-rotation pine trees on watershed D3.

• A long-term water budget and trends in water-quality 

parameters (nutrients and sediment) of control watershed 

D1 under conventional “free” drainage is being evaluated 

during the growth cycle of the pine stand.

• A study is planned to compare downstream water-quality 

effects of fertilizer treatments on the 6- to 7-year-old 

young pine stand on watershed D2 and the 30-year-old 

mature thinned stand on watershed D3 with that of control 

watershed D1. 

• There are plans to study the long-term hydrology of a 

drained pine forest throughout that forest’s life cycle (from

planting to harvest). Modeling outputs obtained by applying DRAINLOB to 40 years of weather data and 16 years 

(1988-2003) of observation data may be used to describe 

the forest’s water and nutrient balances and processes.
11

The Coosawhatchie Bottomland

Ecosystem Study, South Carolina

Site Description

The CBES site (fig. 1) is a 350-ha tract owned by MeadWestvaco Corporation and located in Jasper County, SC, at 

latitude 32°40’N., longitude 80° 55’W., just above tidal influence on the Coosawhatchie River (fig. 3A). The river is a 

fourth-order, anastomosing, blackwater stream that drains a 

1012-km2 watershed (Abrahamsen 1999). The Coosawhatchie River valley is on the Wicomico and Pamlico marine 

terraces and was formed by erosion and downcutting during 

the Pleistocene-Holocene. The flood plain, which is 1.6 km 

wide on the study site, is relatively small and immature 

compared to those of some other rivers in the lower Coastal 

Plain (Murray and others 2000) but is representative of the 

formerly numerous blackwater river flood plains along the 

Atlantic Coast that were drained for agriculture or intensively logged.

There are two weakly developed terraces on the site, and 

these are distinguished by surface sand size and flooding 

frequency. Soils of the lower terrace consist of variable loamy

and clayey Pamlico and recent fluvial sediments over sandy 

fluvial beds. Most are in the Brookman series of fine mixed 

thermic Typic Umbraqualfs. In much of the flood plain there 

is a confining layer of clay at a depth between 30 and 100 cm

(Murray and others 2000). The flood plain’s less scoured 

soils are in the Meggett series, which consists of fine, mixed, 

thermic Typic Albaqualfs. Approximately 20 percent of the 

lower terrace consists of six other soil series; these are characterized by underlying calcareous marine sediments. The 

higher second terrace is a fine-loamy siliceous thermic Typic 

Umbraqualf. 

N

6 miles

6 km

Laurel oak

Mixed oak

Water and

swamp tupelo

Loblolly pine

Continuously

recording

water level

wells

N

300 0 300 600 m

N

200 0 200 400 m

Figure 3—Coosawhatchie River basin with stream gauging stations (A), 

plant communities (B), and treatments (C) in Jasper County, SC.

(A) (B)

(C)
12

There is approximately 2 m of relief on the study site, and

the distinct microtopography is convex hummocks and 

scoured swales with sandy channel bars and small natural 

levees (Murray and others 2000). The hydroperiod is relatively unaltered, as the river has not been channelized and 

dams and levees are not present on the river (Eisenbies and 

Hughes 2000). Land use in the watershed is mainly agriculture (42 percent), forestry (30 percent), and wetlands (24 

percent) (Maluk 2000). Although not cleared and drained for 

agriculture, the study site was high-graded, most recently 

around 1950. There are five forest community types on the 

site. These types are named for the dominant tree species in 

each community: water tupelo (Nyssa aquatica L.), swamp 

tupelo [Nyssa sylvatica var. biflora (Walter) Sargent], laurel 

oak (Quercus laurifolia Michaux), overcup oak (Q. lyrata

Walter), and mixed oak (Burke and others 2003) (fig. 3B).

The CBES is part of two larger studies; it is one of three sites

in the Southern Forested Wetland Research Initiative and 

one of the fixed and integrator sites for the United States 

Geological Survey’s (USGS) National Water Quality Assessment (NAWQA) program for the Santee River basin and 

coastal drainages of NC and SC. In the former program, 

several Federal and State agencies, universities, and forest 

industry are collaborating to develop reference bottomland 

hardwood forests in the South. The latter program is a 

USGS-led multi-agency study of the spatial distribution of 

water quality and quantity and of the mechanisms by which 

human activities and natural factors affect water quality. 

The CBES is a study of ecosystem structure and processes 

in a hydrologically linked terrestrial and aquatic ecosystem. 

It was initiated to address recent public concerns about the 

need for sustainable management, restoration, and protection of forested wetlands. The multi-investigator study 

consists of two phases. Phase 1 was the baseline calibration 

period (1994-99) during which the site was developed as a 

reference or model wetland for comparison purposes. Phase 

2 (2000-05) is a study of the influence of three alternative 

regeneration methods on ecosystem processes (fig. 3C). 

Objectives

• To characterize the hydrology of the site for reference 

purposes. 

• To quantify hydroperiods across the site and relate hydroperiods to forest community structure. 

• To develop hydrologic models for predicting changes in 

water level across the site and for estimating historic 

hydroperiods on the site.

• To produce long-term hydrologic and meteorological 

databases for the site for use in ecosystem and hydrologic 

models.

• To test the influence of three regeneration methods on 

ecosystem processes influenced by hydroperiod. 

Monitoring

Soil was cored deeply to identify the depth and composition 

of deposits and the existence of aquifers on the site. Long-term

river-stage data from 24 km upstream (Hampton Station),

8 km upstream (Early Branch Station), and at the lowest part 

of the study site (Gray’s Station) (fig. 3, table 4) were used 

in conjunction with three additional continuously recording 

water-table wells on the site (fig. 3) and 18 manual PVC wells

installed in permanent productivity plots (Burke and others 

2000) to monitor the elevation of the water table. In addition,

eight piezometers in and adjacent to the river channels were 

used to determine the recharge-discharge relations between 

the ground water and surface water. 

Individual regressions were calculated for water-table elevations on the flood plain. Water-table elevations for observation

wells were used as the dependent variable, and river stage 

(at the Hampton, Early Branch, and Gray’s stations) and 

water-table elevations for three additional continuously 

recording wells were used as independent variables. The 

observation wells were monitored manually, and the best 

regressions were used to model water levels in the four major

communities during the 4 years during which stage data were

collected. These models were used in conjunction with the 

50-year database from the Hampton station to estimate longterm hydroperiod on the site. Recharge and discharge relations between the ground water and surface water were 

determined by monitoring the piezometers during a range of 

river stages. 

Two automatic weather stations with an OMNIDATA data 

logger were installed in the middle of a large opening and 

under the canopy on the study site. These stations continuously measured rainfall, soil and air temperatures, relative 

humidity, wind speed and direction, and solar radiation since 

1994. The weather station under the canopy was removed at 

the end of phase 1 (1999). The data from this station are 

archived at the CFWR for general use. 

The Early Branch gauging station and river reaches between 

the Early Branch and Gray’s stations were established as 

NAWQA fixed and integrator sites in 1995. Fixed sites are 

those that were sampled most intensively during the 3 years 

of the NAWQA study, and the integrator sites are those that 

represented an integration of multiple land covers (Maluk 
13

Table 4—Three stations on the Coosawhatchie River used in Coosawhatchie Bottomland Ecosystem Study

(Burke and Eisenbies 2000): function, information collected, period of operation, and responsibility for operation

USGS Period of Period of

station USGS Forest Service

number Station name Function Data collected operation operation

02176500 Hampton River stage monitoring River stage and streamflow 1951-present —

02176517 Early Branch NAWQA fixed/integrator River stage 1995-1998 1998-present

and CBES study

Nutrients, pesticides, 1995-1998 —

bacteria, suspended

sediments, trace elements

in bed sediments and biota

02176518 Gray’s CBES study River stage — 1995-present

Nutrients, organic carbon, 1995-1998 —

trace elements in bed

sediments and biota

— = not applicable; USGS = United States Geological Survey; NAWQA = National Water Quality Assessment; CBES = Coosawhatchie Bottomland

Ecosystem Study

2000). In addition to stage information, numerous waterquality indicators were monitored by USGS from October 

1995 to September 1997. Details of methods, quality-control 

procedures, and results can be found in Mueller and others 

(1997) and Maluk (2000). After September 1997, USGS 

discontinued the monitoring at the Early Branch and Gray’s 

stream gauging stations, and the CFWR assumed responsibility for maintenance, servicing, data retrieval, and data 

management for these stations. The USGS continues to 

manage the Hampton station.

The Coosawhatchie Early Branch site was established as a 

NAWQA fixed and integrator site. Water-quality samples were

collected monthly from the Coosawhatchie River sites from 

October 1995 through September 1997, as part of the USGS 

NAWQA program. These samples were analyzed for nutrients (phosphorus and several nitrogen species), suspended 

organic carbon, dissolved oxygen, silica, trace metals, and 

pesticides. Details of methods, quality-control procedures, 

and results can be found in Mueller and others (1997) and 

Maluk (2000).

Results to Date

• Deep coring at the site revealed that the surficial aquifer is 

about 9 m thick and consists of alluvial sand and clay 

deposited by the Coosawhatchie River and older Pleistocene

sand and clay. These deposits are underlain by a confining 

unit that is 12 m thick, which in turn overlies the Floridan 

aquifer, which is about 21 m deep (Eisenbies and Hughes 

2000). 

• Hydrology on the site was typical of blackwater rivers: 

flooding is of relatively short duration and may be followed

by extensive periods of low discharge, floodwaters may be 

deep and widespread, and droughts also occur (Burke and 

Chambers 2003). 

• Long-term hydrologic records showed that hydroperiods 

were variable both within and among years and that duration of flooding was shorter in recent years than formerly 

(Burke and others 2003). 

• The potentiometric surface of the Floridan aquifer is 

approximately 0.5 m above land surface at the study site. 

This represents a decline of approximately 5 m during the 

last decade and is the result of ground-water withdrawals 

for municipal and industrial water supplies (Hughes and 

others 1989). The documented drop in potentiometric surface is consistent with the shortened duration of flooding 

measured in recent years. These observations suggest that 

the site is becoming drier and that withdrawal of water 

from the aquifer may be affecting wetlands (Burke and 

others 2003).

• Discharge of ground water is the dominant hydrological 

condition on the study site, but recharge can occur during 

extremely high flows. 
14

• The river generally crests 3 to 4 days after rain events in 

the watershed. Crests at the Gray’s station are 2 to 3 days 

after crests at the Hampton station (Eisenbies and Hughes 

2000), so regressions using river stages were used in 

predictive models of ground water.

• Regressing water-table elevations for observation and continuously recording wells on river stages yielded correlation

coefficients that ranged from 0.56 to 0.97. Water levels in 

wells closest to the river generally correlated best with 

river stage (Eisenbies and Hughes 2000). 

• The forest communities had distinct hydrologic regimes. 

Sites could be ranked from wettest to driest by percentage 

of time flooded on both water year and growing season 

(March 15 to October 1) bases. For the previous 50 years 

(1951-2000), the mean time flooded during the growing 

season was 79 percent for water tupelo, 68 percent for 

swamp tupelo, 38 percent for laurel oak and overcup oak, 

and 19 percent for mixed oak (Burke and others 2003). 

Also, ground cover and species diversity values were 

inversely correlated to flooding frequency (Billups and 

Burke 1999).

• Hydrologic connectivity (degree of flow-path connection 

to the main channel) affected sedimentation rates. Highest 

deposition rates occurred near sloughs and their anabranches

that have a direct flow path to the river (Hupp 2000).

• The annual streamflow is among the smallest for southeastern Coastal Plain rivers, and the sediment load is relatively light (5 to 25 mg L-1) compared with that of other 

Coastal Plain rivers, including other blackwater rivers 

(Hupp 2000). Concentrations of suspended sediment in 

the Coosawhatchie River are similar to those in another 

blackwater river, the Edisto (Maluk 2000). The flood plain 

appears effective at removing suspended sediment (24.5 

kg ha-1 yr-1) via sediment deposition (0.02 to 0.20 cm yr-1) 

(Hupp 2000).

• The Coosawhatchie River exhibited a seasonal trend in 

nutrient concentrations, with low concentrations in winter 

and significantly higher concentrations in summer, possibly

because total organic nitrogen present in the form of detritus

was lower during the winter. Nitrate concentrations in the 

river were low, as is expected for forested watersheds. 

Dissolved phosphorus concentrations in the Coosawhatchie

River were among the highest in the basin.

Next Steps

• Evaluate the short-term and long-term hydroperiods on 

these forested lands using hydrologic models like 

DRAINMOD to determine wetland hydrology.

• Address the potential impact of ground-water use on flood 

plain resources, including vegetation in the region, using a 

comprehensive hydrologic model.

• Conduct studies on impacts of harvesting and regeneration 

of bottomland hardwoods.

• Study impacts of upland management practices on 

hydrology and water quality. 

Study on High-Intensity Short-Rotation 

Woody Crop Site at Trice Farm,

South Carolina

Site Description

A study on a hardwood plantation forest, which is owned and

managed by the International Paper Company and located in 

the upper Coastal Plain of SC (fig. 1), was initiated in 1997 as

part of the U.S. Department of Energy’s Agenda 2020 Program

to provide a bridge between small-scale plot studies and 

large-scale assessment models. The study is a collaborative 

effort of Oak Ridge National Laboratory, the International 

Paper Company, NC State University, the University of 

Nevada, the College of Charleston, and the Forest Service. 

The plantation forest, which was previously a farm, is now 

used for research on intensively managed SRWC and operational plantations. The forest is located on the upper Coastal 

Plain, approximately 1.6 km southwest of Mayesville in 

Sumter County, SC (fig. 4). It was historically planted with 

cotton, soybeans, and wheat, with a small portion of land in 

pasture and natural pine-hardwood forest. Some natural forest

is present at this time, primarily in headwater reaches and 

riparian zones. The study site occupies ~120 ha. It is located 

on former agricultural fields that are situated in a way that 

facilitates the measurement of all inputs and outputs from the

system. The first rotation of SRWC sycamore (Platanus occidentalis L.) and sweetgum (Liquidambar styraciflua L.) was 

planted on the study catchments in February 1997. The soils 

on the site are typified by the Goldsboro, Norfolk, Coxville, 

and Rains soil series, which are characteristic of the upper 

Coastal Plain, and they have been drained artificially. 

Objectives

• To determine the effects of operational SRWC plantations 

on soil chemical and physical properties and on nutrients 

in surface and subsurface runoff.

• To determine the hydrologic and nutrient cycling processes

of SRWC plantations.
15

• To determine the potentially beneficial effects of alternative

management practices on productivity, soil sustainability, 

and offsite movement of nutrients and chemicals. Both field

instrumentation and modeling are employed. The models 

used are a process-based hydrologic model, WATRCOM 

(Parsons and others 1991), and a biogeochemical model, 

NuCM.

• To evaluate the potential of SRWC systems to sequester 

carbon and enhance soil tilth.

Methods 

The study was designed at a watershed scale because many 

processes are manifested differently at plot (0.4 ha) and stand

(> 2 ha) scales. The watershed scale provides the conditions 

necessary for understanding productivity and sustainability 

at an operational level. The presence of adjacent natural 

forests, which can be used as a reference system, also facilitates the assessment of the conversion of agricultural land 

into intensively managed woody crop plantations. 

Measurements were taken at a large watershed scale and a 

smaller catchment scale (table 5). Measurements of flow, 

soil moisture, weather, and nutrient parameters were done

at six experimental catchments (4 to 6 ha), and an 200-ha 

second-order watershed was instrumented for flow measurement to provide baseline data for assessing the long-term 

effects of SRWC on water quality and quantity. Detailed 

studies of nitrogen mineralization and organic matter 

decomposition have been conducted.

A CR10X automatic weather station in the middle of the 

watershed continuously measures air temperature, humidity, 

wind speed, and solar radiation. Precipitation is measured by 

a tipping bucket rain gauge attached to a HOBO data logger 

adjacent to the weather station. Prefabricated plastic flumes 

with WL-15 and GL-300 data loggers are used to estimate 

flow rates both at the catchment and watershed outlets.

Three treatments were designed to represent established 

practices of SRWC culture (with two replicate catchments 

per treatment): (1) sweetgum, herbicide application, open 

drainage; (2) sycamore, herbicide application, open drainage;

and (3) sycamore, cover crop, controlled drainage structure. 

These treatments represent commercially feasible combinations of tree species, fertilization, weed control, and water 

Sycamore plantation

Sweetgum plantation

Green ash plantation

Natural

Loblolly plantation

Reserved for research

Nonforested

Non-IP property

(agricultural, residential,

and church)

International Paper

Goza Tract

Trice Research Forest

N

E

S

W

2,000 0 2,000 4,000 feet

Land use

3/08/02 JEC

Figure 4—Layout of International Paper’s Trice Forest in the upper Coastal Plain near Sumter, SC.
16

Table 5—Summary of meteorological, hydrologic, water quality, soil and vegetation data used to assess treatment 

responses and cumulative development of the watersheds and catchments

Data type Measurement Method Scale Sample period

Meteorological Temperature Thermocouple Watershed Continuous 

Precipitation Gauge Watershed Continuous

Hydrologic Stream stage Water level recorders Watershed and Continuous

(electronic and chart catchment

types)

Stream flow Trapezoidal flumes Watershed and Continuous

and V-notch weirs catchment

Water table elevation Deep (4.6 m) and Catchment 1997-2002: monthly

shallow (1.8 m)

well pairs

Water quality Soil water analysis: Hanging-column Catchment 1998-2002: monthly

PO4

, NH4, NO3, Mg, tension lysimeters

K, Ca (1 m deep) 

Stream water analysis: ISCO 3700 portable Watershed and 1998-2002: storm event 

TN, TP, NO3, NH4, Ca, samplers catchment samples plus weekly 

Mg, K, sediment composite samples

Soil chemical Extractable cations, TC, Cores (15-75 cm) Plot 1997-1999, 2001

properties TN, N-mineralization Sequential cores Plot 2001-2002 

Decomposition Litter bags Plot 2001-2004

Soil physical Bulk density Cores Catchment 1998-2001: annual

properties Infiltration Single-ring infiltro- Catchment 1998

meter, cores

Vegetation Tree growth Diameter Plot 1997-2002: annual

above ground tapes, calipers, 

telescoping poles

Tree mortality Visual Plot 1997-2002: annual 

Below-ground biomass Cores Catchment 1997-2002: periodic 

Litter 1.25 m2

 collectors Plot 1997-2002: monthly

management regimes. Detailed description of the site and 

treatments can be found elsewhere (Trettin and Davis 2002).

Results to Date

• Sycamore has been significantly more productive than 

sweetgum over the first 6 years, averaging 40 Mg ha-1

biomass compared to 15 Mg ha-1 for sweetgum in 6 years. 

Use of the controlled drainage system has not affected 

sycamore productivity, probably because an extended 

drought occurred during the first 4 years following plantation establishment. 

• The WATRCOM model (Parsons and others 1991) was 

successfully applied to this silvicultural system (Parsons 

and Trettin 2001). Simulations demonstrated that the controlled drainage should be effective in increasing available 

soil water during periods with normal precipitation.

• Short-rotation woody crop management systems had no 

deleterious effects on water quality. Sycamore treatments 
17

were associated with significantly higher nitrogen concentrations in the soil water and drainage water, but these 

concentrations were well below the allowable maximum 

for drinking water. Applied pesticides had minimal effect 

on water or the aquatic organisms in the channel.

• The first-order channels and second-order streams are 

extremely “flashy,” and this demonstrates the importance 

of effective riparian zone management. 

• The SRWC systems improve soil tilth (Tolbert and others 

2000), enhance wildlife habitat (Tolbert and others 2002), 

and improve water quality.

• The study and its infrastructure, and the WATRCOM model,

provide a basis for long-term assessments of nutrient 

cycling and transport from the SRWC system in the upper 

Coastal Plain.

• The study also provides for the operational scale assessment of SRWC and the development of tools needed to 

plan and manage these crops.

Next Steps

• Use monitoring and modeling to determine the effects of 

changing land use from agriculture to forests and SRWC 

on hydrology and water quality at the watershed scale. 

• Use hydrologic data from the catchments at this study site 

to test and compare results obtained by using DRAINMOD

and WATRCOM. 

• Test the validity of remotely sensed data that characterize 

plant productivity and soil conditions.

• Continue to monitor soil processes to determine the rates 

of carbon sequestration and nitrogen turnover in the 

managed plantations. 

Study of Depressional Isolated Wetlands 

(Carolina Bays) at Burch Fiber Farm, 

South Carolina

Site Description

The research site for the depressional isolated wetlands is 

located at Burch Fiber Farm, which is near Olar in Bamberg 

County, SC, and is owned and operated by MeadWestvaco 

(figs. 1 and 5). The depressional wetland referred to herein 

as Chapel Bay has an area of 6 ha. Bottomland hardwoods 

occupy its interior. Soils are poorly drained sandy loams. 

Surrounding uplands consist of croplands, intensively managed hardwoods, and natural pine stands. There are two other

wetlands at the site, Cathedral Bay (22 ha) and Potato Bay 

(0.4 ha). Cathedral Bay, a preserved Carolina bay owned by 

500 0 500 m

N

Figure 5—Location map (left side) and experimental layout of groundwater wells at Chapel Bay, near Olar, SC.
18

the SC Heritage Land Trust, supports a pure stand of pond 

cypress and is adjacent to the Burch farm. The surficial 

aquifer lies approximately 5 to 8 m below the ground surface

at the site. The general stratigraphy of the site to approximately

10 m depth was determined by examining well logs. Soil 

horizon layers A and E are composed mainly of sand in the 

upland areas and range from sandy loams to loamy sands 

within the wetlands. Horizon B is composed of sandy clay 

loams in the uplands and sandy clay loam and sandy clay 

within the wetlands. Soil layers below the horizons are alternating clay and sand layers, which is characteristic of the 

surficial aquifer system. Pyzoha (2003) describes the soil 

types and logging in detail. Average annual rainfall at the site

is 1200 mm, and the average annual maximum and minimum

temperatures are 23.4 °C and 11.3 °C, respectively. 

Objectives

• To examine potential surface-water and ground-water 

interactions (first examined by Miwa and others 20043) and 

thus identify the interaction between Carolina bays and the 

adjacent uplands (fig. 5, left), and to assess the effects of 

the interactions between Carolina bays and adjacent 

uplands on the regional water balance by means of conceptual models.

• To test the performance of the distributed forest hydrologic model FLATWOODS (Sun and others 1998a, 1998b,

2004) in evaluating the surface and subsurface waterflow 

patterns and their interactions with surrounding uplands.

Methods 

Precipitation and air temperatures were measured continuously with an automatic tipping bucket rain gauge and a 

temperature probe at the Burch farm. Well logging was used 

to identify the stratigraphy to a 10-m depth. About 46 PVC 

and stainless steel pipe wells and PVC pipe piezometers

(6 with data loggers) were installed in three transects within 

Chapel Bay and two transects within Potato Bay to monitor 

water-table levels since 1997 (fig. 5, right). Surface flow, soil 

water, and shallow ground water were monitored. In addition,

three piezometers were installed in the upland area to assess 

interactions between Carolina bays and their surrounding 

areas. Automatic digital recording wells equipped with data 

loggers were also installed near the center of each of the bays.

Water levels were measured monthly from February 2002 to 

December 2003. Water levels measured between 1997 and 

1999 (Miwa and others 2004) were also evaluated. Positions 

of existing wells and piezometers were determined using a 

rotary laser level, Philadelphia rod, and GPS unit. In addition, 

a 700-m by 700-m area was surveyed for elevations needed 

for hydrologic modeling. Slug tests were performed to determine hydraulic conductivities. Details of field experimental 

procedures are described by Pyzoha (2003). 

Results to Date

• Minimal surface and ground-water interactions occurred 

during dry periods, indicating that the bays are hydrologically isolated during these periods (Pyzoha 2003). 

• During wet periods, the bays served as a storage site for 

stormwater, and perhaps as locations of ground-water 

recharge, interacting with surrounding regions (fig. 5).

• The study suggested that Carolina bays may not be 

isolated systems.

• The distributed hydrologic model FLATWOODS (Sun and

others 1998a) suggests that Chapel Bay is a flow-through 

wetland, losing ground water to the lower recharge area, 

especially during wet winter periods (Sun and others 2004).

The simulation study also suggests that ground-water flow 

direction is controlled by the gradient of the underlying 

restricting layer, not by the topographic gradient. Wetland 

position on the landscape is one important factor in determining the hydrologic interactions between the wetland and

its surrounding upland. Testing also suggests that the model

is able to capture the spatial and temporal dynamics of a 

shallow ground-water table in a heterogeneous landscape.

Next Steps

• Test the applicability of DRAINMOD (Skaggs 1978) to 

Carolina bays by running the program with data from the 

Burch farm and comparing the results with those obtained 

by running FLATWOODS.

• Refine and evaluate these models for application to wetland hydrology and to interactions of hydroperiods with 

soils and vegetation on coastal forested landscapes. 

Summary and Recommendations

Five long-term and short-term ecohydrologic studies are 

being conducted by the Forest Service Center for Forested 

Wetlands Research (Charleston, SC) in the forested wetlands

of the Atlantic Coastal Plain. These studies have contributed 

to our understanding of the hydrologic and nutrient cycling 

processes that occur on naturally drained and artificially 

drained low-gradient coastal forested watersheds. The knowledge that has been gained is being used to reduce offsite 

impacts and maintain productivity on this forested landscape. 3 Miwa, M.; Trettin, C.C.; O’Ney, S.E.; Eisenbies, M.H. 2004. Hydrologic 

processes in the vicinity of a Carolina bay. On file with: International Paper 

Company, 719 Southland Road, Bainbridge, GA 39819.
19

The low-gradient coastal landscape is a mosaic of managed 

forests, depressional wetlands, bottomland hardwoods, 

riparian zones, and other natural forests. Its character is 

further complicated by site-specific hydrologic factors, pressures for land development, management practices, and 

climatic factors. The Southern Forest Resource Assessment 

(Wear and Greis 2002) clearly depicted the challenges to 

sustaining the environmental quality and social values of 

this landscape. The need to understand and manage the 

region’s water resources is a critical challenge. To meet this 

challenge, we recommend the following:

• Additional emphasis is needed on hydrologic studies of 

forests, wetlands, and riparian zones on the flat coastal 

landscapes drained by low-gradient streams and rivers. 

These lands are a vital source for clean water, forest products, carbon sequestration, and wildlife habitat, but the 

influences of hydrology on these outputs have not been 

adequately addressed to meet the current and projected 

management needs.

• Studies are urgently needed that consider the effects of land

use change (for example, from forest cover to urban, or 

agriculture to forest) on ecohydrologic and biogeochemical

processes. Better understanding of the biogeochemical 

processes that affect water quality is needed to guide land 

use and development, including the development of engineered or restored lands to enhance water quality and 

healthy forests to provide a clean and stable water supply. 

One of the biggest challenges will be developing and 

applying ecohydrologic models capable of predicting the 

processes and the effects of management and climatic 

factors at various spatial and temporal scales. Data from 

the existing weather stations maintained by CFWR and its 

cooperators may be used for ground truthing (field verification) of radar data and other remote sensing data (for 

example, temperature, radiation, albedo, vegetation type, 

LAI), which are becoming a part of the next generation of 

ecohydrologic modeling tools.

• Studies at the large watershed scale or basin scale are 

needed to examine the interactions of uplands and lowlands,

in-stream processes, land management and land use change,

climate, and social factors. The empirical studies discussed

in this report can provide the basis for such large-scale 

assessment. Critical attention must be given to the uncertainties associated with scaling issues in both the monitoring and modeling phases. 

• Long-term (> 10-year) studies are needed to support hydrologic research. This is because hydrology is influenced by 

temporal and spatial variation in climate, soils, vegetation, 

and topography. The existing hydrologic studies and infrastructure at the Forest Service Santee Experimental Forest 

near Charleston, SC, can be a basis for the continuation of 

the long-term hydrologic studies and studies of prescribed 

burning, regeneration and management of bottomland 

hardwoods, and carbon sequestration in coastal forest 

ecosystems. Similarly, the current long-term database and 

ongoing activities associated with the CBES provide a 

reference system and a basis for increasing our knowledge 

of hydroperiod, vegetation dynamics, and biogeochemical 

processes, as they relate to bottomland hardwood forests. 

Also, the site of the ongoing long-term study on a 

managed pine forest at Carteret County, NC, can be 

another site for expanding research on impacts of forest 

management on the lower Coastal Plain. 

The most effective way to address the numerous scientific 

questions and management challenges relative to water 

resources in the Southeast is through collaboration among 

academia, industries, State and Federal government agencies,

private land owners, and nongovernmental organizations to 

build and share a long-term ecohydrological database, identify new prioritized issues, conduct experimental studies, and

implement the recommended science and technology using 

appropriate technology transfer approaches. The facilities 

mentioned provide an excellent foundation for building those

collaborative efforts. In this context, CFWR has been updating

its hydrometeorologic database from the experimental watersheds on the HYDRO-DB, a Web-based data sharing and 

harvesting site (http://www.fsl.orst.edu/climhy/hydrodb/).

We hope that this type of database and our long-term hydrologic research facilities can increase the level of collaboration and our collective abilities to address the many water 

resource issues facing the Southeastern United States.

Acknowledgments

This work was supported by the U.S. Department of

Agricuture Forest Service Center for Forested Wetlands 

Research, the National Council for Air and Stream 

Improvement, Inc., and MeadWestvaco, Inc. The authors 

also acknowledge the staff of the Francis Marion National 

Forest, Charleston, SC, for their collaboration in this 

research. 

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The U.S. Department of Agriculture Forest Service Center for Forested Wetlands Research has 

conducted or cooperated in studies designed to improve understanding of fundamental hydrologic 

and biogeochemical processes that link aquatic and terrestrial ecosystems. Five of these studies 

are discussed here. The first is based on observations made on long-term experimental watersheds 

established in the 1960s on the Forest Service Santee Experimental Forest in South Carolina. It 

quantifies the soil moisture dynamics, flow regimes, and water chemistry of low-gradient forested 

wetlands. The second study is being conducted in cooperation with North Carolina State University. 

It is a long-term project aimed at quantifying the effects of various water management and 

silvicultural management practices on hydrology and water quality at the Weyerhaeuser Company’s 

managed pine forest in Carteret County, North Carolina. The third study is a long-term ecosystem 

study on MeadWestvaco’s Coosawhatchie River bottomland hardwood site in South Carolina. 

It addresses questions related to public concerns about the need for protection, restoration, and 

sustainable management of forested wetlands. The fourth study, which was conducted between 1997 

and 2000, examined the hydrology and water quality of intensively managed short-rotation woody 

crop plantations on International Paper’s Trice experimental forest in the upper Coastal Plain of 

South Carolina. A fifth study was conducted between 1996 and 2004 at MeadWestvaco’s Carolina 

bay site in the South Carolina upper Coastal Plain; it assessed the surface-water and ground-water 

interactions between Carolina bays and their surrounding uplands. Recommendations are provided 

for using knowledge gained through these and other studies as a basis for expanding needed 

hydrologic research with collaborators to address four major areas of water-related issues in the 

Southeast.

Keywords. Forested wetlands, management impacts, models, vegetation, water management,

water quality, watershed.
The Forest Service, United States Department of 

Agriculture (USDA), is dedicated to the principle of 

multiple use management of the Nation’s forest resources 

for sustained yields of wood, water, forage, wildlife, and recreation. 

Through forestry research, cooperation with the States and private 

forest owners, and management of the National Forests and 

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increasingly greater service to a growing Nation.

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