National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 

Southeast Coast Network Surface Water Discharge 

Monitoring 

Analysis of Existing Data and Data Acquisition Applications 

Natural Resource Report NPS/SECN/NRR—2010/264 
ON THE COVER 

Wise Lake at Congaree National Park 

NPS Photo 
Southeast Coast Network Surface Water Discharge 

Monitoring 

Analysis of Existing Data and Data Acquisition 

Applications 

Natural Resource Report NPS/SECN/NRR—2010/264 

C. D. Jones, A. M. Couch, R. D. Sherrell, and T. C. Rasmussen 

Warnell School of Forestry and Natural Resources 

The University of Georgia 

Athens, GA 30602 

J. F. Dowd 

Department of Geology 

The University of Georgia 

Athens, GA 30602 

November 2010 

U.S. Department of the Interior 

National Park Service 

Natural Resource Program Center

Fort Collins, Colorado 
ii 

The National Park Service, Natural Resource Program Center publishes a range of reports that 

address natural resource topics of interest and applicability to a broad audience in the National 

Park Service and others in natural resource management, including scientists, conservation and 

environmental constituencies, and the public. 

The Natural Resource Report Series is used to disseminate high-priority, current natural resource 

management information with managerial application. The series targets a general, diverse 

audience, and may contain NPS policy considerations or address sensitive issues of management 

applicability. 

All manuscripts in the series receive the appropriate level of peer review to ensure that the 

information is scientifically credible, technically accurate, appropriately written for the intended 

audience, and designed and published in a professional manner. This report received formal peer 

review by subject-matter experts who were not directly involved in the collection, analysis, or reporting 

of the data, and whose background and expertise put them on par technically and scientifically with the 

authors of the information. 

Views, statements, findings, conclusions, recommendations, and data in this report do not 

necessarily reflect views and policies of the National Park Service, U.S. Department of the 

Interior. Mention of trade names or commercial products does not constitute endorsement or 

recommendation for use by the U.S. Government. 

This report is available in the Reports and Publications section of the Southeast Coast Inventory 

and Monitoring Network webpage (http://science.nature.nps.gov/im/units/secn/) and the Natural 

Resource Publications Management website (http://www.nature.nps.gov/publications/NRPM). 

Please cite this publication as: 

Jones, C. D., A. M. Couch, R. D. Sherrell, T. C. Rasmussen, and J. F. Dowd. 2010. Southeast 

Coast Network surface water discharge monitoring: Analysis of existing data and data 

acquisition applications. Natural Resource Report NPS/SECN/NRR—2010/264. National Park 

Service, Fort Collins, Colorado. 

NPS 910/106018, November 2010 
iii 

Contents 

Page 

Figures............................................................................................................................................. v

Tables ............................................................................................................................................. ix

Appendices ..................................................................................................................................... xi

Abstract ........................................................................................................................................ xiii

Glossary of Terms ......................................................................................................................... xv

Background ..................................................................................................................................... 1

Project Overview ..................................................................................................................... 1

Population Changes ................................................................................................................. 2

Climate Change ....................................................................................................................... 2

Project Objectives .................................................................................................................... 3

Literature Review............................................................................................................................ 5

CHAT: Chattahoochee National Recreation Area ................................................................... 7

CONG: Congaree National Park ............................................................................................. 8

FOFR: Fort Frederica National Monument ........................................................................... 10

FOMA: Fort Matanzas National Monument ......................................................................... 10

FOPU: Fort Pulaski National Monument .............................................................................. 10

FOSU: Fort Sumter National Monument .............................................................................. 11

HOBE: Horseshoe Bend National Military Park ................................................................... 12

KEMO: Kennesaw Mountain National Battlefield Park ....................................................... 12

MOCR: Moores Creek National Battlefield .......................................................................... 12

OCMU: Ocmulgee National Monument ............................................................................... 13

TIMU: Timucuan Ecological and Historic Preserve ............................................................. 13

Summary ................................................................................................................................ 13
iv 

Surface Water Quantity Monitoring and Data Analysis Protocols ............................................... 15

Stage ...................................................................................................................................... 15

Discharge ............................................................................................................................... 15

Inventory and Flow Analysis ................................................................................................. 16

CHAT: Chattahoochee National Recreation Area ................................................................. 17

CONG: Congaree National Park ........................................................................................... 23

FOFR: Fort Frederica National Monument ........................................................................... 29

FOMA: Fort Matanzas National Monument ......................................................................... 32

FOPU: Fort Pulaski National Monument .............................................................................. 34

FOSU: Fort Sumter National Monument .............................................................................. 37

HOBE: Horseshoe Bend National Military Park ................................................................... 40

KEMO: Kennesaw Mountain National Battlefield Park ....................................................... 47

MOCR: Moores Creek National Battlefield .......................................................................... 52

OCMU: Ocmulgee National Monument ............................................................................... 54

TIMU: Timucuan Ecological and Historic Preserve ............................................................. 59

Summary of Water Quantity Monitoring at SECN Parks ............................................................. 63

Surface Water Concerns and Suggested Methods for Analysis .................................................... 65

Recommendations ......................................................................................................................... 75

Bibliography ................................................................................................................................. 79
v 

Figures 

Page 

Figure 1. Conceptual model of factors influencing freshwater ecosystems .................................. 5

Figure 2. Land cover and watershed map for Chattahoochee National Recreation Area 

(CHAT). ........................................................................................................................................ 18

Figure 3. USGS Gage 02335000. Average daily flow of the Chattahoochee River pre- and 

post-construction of Buford Dam near Norcross, GA. ................................................................. 19

Figure 4. USGS Gage 02335000. Log Pearson III graph of high-flow return frequency for 

the Chattahoochee River near Norcross, GA, prior to the construction of Buford Dam. ............. 20

Figure 5. USGS Gage 02335000. Log Pearson III graph of high-flow return frequency for 

the Chattahoochee River near Norcross, GA, after the construction of Buford Dam. ................. 20

Figure 6. USGS Gage 02335000. Log Pearson III graph of the seven-day low-flow return 

frequency for the Chattahoochee River near Norcross, GA, prior to the construction of 

Buford Dam. ................................................................................................................................. 21

Figure 7. USGS Gage 02335000. Log Pearson III graph of the seven-day low-flow return 

frequency for the Chattahoochee River near Norcross, GA, after the construction of Buford 

Dam. .............................................................................................................................................. 21

Figure 8. USGS Gage 02335000. Single day (dots) and seven-day (triangles) flow duration 

curves for single-day flow on the Chattahoochee River near Norcross, GA, prior to the 

construction of Buford Dam. ........................................................................................................ 22

Figure 9. USGS Gage 02335000. Single day (dots) and seven-day (triangles) flow duration 

curves for single-day flow on the Chattahoochee River near Norcross, GA, after to the 

construction of Buford Dam. ........................................................................................................ 22

Figure 10. Land cover and watershed map (HUC 4) for Congaree National Park (CONG). ...... 24

Figure 11. USGS Gage 02169500. Average daily flow of the Congaree River at Columbia, 

SC. ................................................................................................................................................. 25

Figure 12. USGS Gage 02169500. Log Pearson III graph of high-flow return frequency for 

the Congaree River at Columbia, SC. ........................................................................................... 26

Figure 13. USGS Gage 02169500. Log Pearson III graph of the seven-day low-flow return 

frequency for the Congaree River at Columbia, SC. .................................................................... 26

Figure 14. USGS Gage 02169500. Flow duration curves for seven-day (triangles) and single 

day (dots) flow duration for the Congaree River at Columbia, SC. ............................................. 27
vi 

Figure 15. USGS Gage 02148315. Average daily flow for the Wateree River below 

Eastover, SC. ................................................................................................................................. 27

Figure 16. USGS Gage 02148315. Log Pearson III graph of high-flow return frequency for 

the Wateree River below Eastover, SC. ........................................................................................ 28

Figure 17. USGS Gage 02148315. Log Pearson III graph of seven-day low-flow return 

frequency for the Wateree River below Eastover, SC. ................................................................. 28

Figure 18. USGS Gage 02148315. Flow duration curves for seven-day (triangles) and single 

day (dots) flow duration for the Wateree River at Columbia, SC. ............................................... 29

Figure 19. Land cover and watershed map for Fort Frederica National Monument (FOFR). ..... 30

Figure 20. USGS 0226180. Daily stream height located near Fort Frederica. ............................ 31

Figure 21. Land cover and watershed map for Fort Matanzas National Monument (FOMA). ... 33

Figure 22. USGS 02244040. Daily stream height located near Fort Matanzas (FOMA). ........... 34

Figure 23. Land cover and watershed map for Fort Pulaski National Monument (FOPU). ........ 36

Figure 24. USGS gage 02198980. Gage height on the Savannah River at Fort Pulaski, GA. ..... 37

Figure 25. Land cover and watershed map for Fort Sumter National Monument (FOSU). ........ 38

Figure 26. USGS 02172100 located at Fort Sumter near Mt. Pleasant, SC. ................................ 39

Figure 27. USGS 021720711 on the Cooper River at Customs House at Charleston, SC, 

near Fort Sumter. .......................................................................................................................... 40

Figure 28. Land cover and watershed map for Horseshoe Bend National Military Park 

(HOBE). ........................................................................................................................................ 42

Figure 29. USGS 02414500. Average daily flow for the Tallapoosa River at Wadely, AL. ...... 43

Figure 30. USGS 02414500. Average daily flow for the Tallapoosa River at Wadely, AL, 

after the construction of the R.L. Harris Dam. ............................................................................. 43

Figure 31. USGS 2414715. Average daily flow for the Tallapoosa River near New Site, AL, 

(Horseshoe Bend).......................................................................................................................... 44

Figure 32. USGS 02414500. Log Pearson III graph of the high-flow return frequency for 

the Tallapoosa River at Wadely, AL, prior to the construction of R.L. Harris Dam. ................... 44

Figure 33. USGS 02414500. Log Pearson III graph of the high-flow return frequency for 

the Tallapoosa River at Wadely, AL, after the construction of R.L. Harris Dam. ....................... 45
vii 

Figure 34. USGS 02414500. Log Pearson III graph of the seven-day low-flow return 

frequency for the Tallapoosa River at Wadely, AL, prior to the construction of R.L. Harris 

Dam. .............................................................................................................................................. 45

Figure 35. USGS 02414500. Log Pearson III graph of the seven-day low-flow return 

frequency for the Tallapoosa River at Wadely, AL, after the construction of R.L. Harris 

Dam. .............................................................................................................................................. 46

Figure 36. USGS 02414500. Flow duration curves for seven-day (triangles) and single day 

(dots) flow duration for the Tallapoosa River at Wadely, AL, prior to the construction of 

R.L. Harris Dam. ........................................................................................................................... 46

Figure 37. USGS 02414500. Flow duration curves for seven-day (triangles) and single day 

(dots) flow duration for the Tallapoosa River at Wadely, AL, after the construction of R.L. 

Harris dam. In 2003, a large flood event increased the single day average to approximately 

85,000 cfs, the highest on record. ................................................................................................. 47

Figure 38. Land cover and watershed map for Kennesaw Mountain National Battlefield 

Park (KEMO). ............................................................................................................................... 49

Figure 39. USGS 02336968 on Noses Creek at Powder Springs Road in Powder Springs, 

GA, south of Kennesaw Mountain National Battlefield Park. ...................................................... 50

Figure 40. USGS 02336968. Log Pearson III for high-flow events on Noses Creek at 

Powder Springs Road in Powder Springs, GA, south of Kennesaw Mountain National 

Battlefield Park. ............................................................................................................................ 50

Figure 41. USGS 02336968. Log Pearson III for low-flow events on Noses Creek at Powder 

Springs Road in Powder Springs, GA, south of Kennesaw Mountain National Battlefield 

Park. .............................................................................................................................................. 51

Figure 42. USGS 02336968. Flow duration curves for 7-day (triangles) and single day 

(dots) flow duration for Noses Creek at Powder Springs Road in Powder Springs, GA, south 

of Kennesaw Mountain National Battlefield Park. ....................................................................... 51

Figure 43. Land cover and watershed map for Moores Creek National Battlefield (MOCR). .... 53

Figure 44. Land cover and watershed map of Ocmulgee National Monument (OCMU). .......... 56

Figure 45. Average daily flow for USGS 02213000 located on the Ocmulgee River at 

Macon, GA, south of Ocmulgee National Monument. ................................................................. 57

Figure 46. Log Pearson III graph of high-flow return frequency for USGS 02213000 located 

on the Ocmulgee River at Macon, GA, south of Ocmulgee National Monument. ....................... 57

Figure 47. Log Pearson III graph of low-flow return frequency for USGS 02213000 located 

on the Ocmulgee River at Macon, GA, south of Ocmulgee National Monument. ....................... 58
viii 

Figure 48. Flow duration curves for seven-day (triangles) and single-day (dots) flow 

duration for USGS 02213000 located on the Ocmulgee River at Macon, GA, south of 

Ocmulgee National Monument. .................................................................................................... 58

Figure 49. Land cover and watershed map for Timucuan Ecological and Historic Preserve 

(TIMU). ......................................................................................................................................... 60

Figure 50. USGS 02231289 on the Nassau River near Hedges, FL, and within the boundary 

of Timucuan Ecological and Historic Preserve. ........................................................................... 61

Figure 51. USGS 02246500 on the St. Johns River at Jacksonville, FL, near Timucuan 

Ecological and Historic Preserve. ................................................................................................. 61

Figure 52. Range of Variability analysis for the Chattahoochee River near Norcross, GA. ....... 73

Figure 53. Graph of the frequency of extreme low flows, low flows, high-flow pulses, small 

floods, and large floods near Norcross, GA, before and after the construction of Buford 

Dam. .............................................................................................................................................. 73

Figure 54. Graph of the frequency of extreme low-flow events on the Chattahoochee River 

near Norcross, GA, before and after the construction of Buford Dam. ........................................ 74

 
ix 

Tables 

Page 

Table 1. Southeast Coast Network (SECN) National Park units covered in this report. ............... 1

Table 2. Recent and projected populations for counties containing SECN parks. ......................... 2

Table 3. Surface water gages within or near SECN parks and periods of record for discharge 

and gage height. .............................................................................................................................. 6

Table 4. Chattahoochee National Recreation Area (CHAT) landcover within the park, 

within a 5-km buffer, and its HUC 8 watershed. .......................................................................... 19

Table 5. Congaree National Park (CONG) landcover within the park, within a 5-km buffer, 

and its HUC 8 watershed. ............................................................................................................. 25

Table 6. Fort Frederica National Monument (FOFR) land cover within the park, within a 5-

km buffer, and its HUC 8 watershed. ........................................................................................... 31

Table 7. Fort Matanzas National Monument (FOMA) land cover within the park, within a 5-

km buffer, and its HUC 8 watershed. ........................................................................................... 32

Table 8. Fort Pulaski National Monument (FOPU) land cover within the park, within a 5-

km buffer and its HUC 8 watershed. ............................................................................................ 35

Table 9. Fort Sumter National Monument (FOSU) land cover within the park, within a 5-km 

buffer, and its HUC 8 watershed. .................................................................................................. 39

Table 10. Horseshoe Bend National Military Park (HOBE) land cover within the park, 

within a 5-km buffer, and its HUC 8 watershed. .......................................................................... 42

Table 11. Kennesaw Mountain National Battlefield Park (KEMO) land cover within the 

park, within a 5-km buffer, and its HUC 8 watershed. ................................................................. 48

Table 12. Moores Creek National Battlefield (MOCR) land cover within the park, within a 

5-km buffer, and its HUC 8 watershed. ........................................................................................ 54

Table 13. Ocmulgee National Monument (OCMU) land cover within the park, within a 5-

km buffer, and its HUC 8 watershed. ........................................................................................... 55

Table 14. Timucuan Ecological and Historic Preserve (TIMU) land cover within the park, 

within a 5-km buffer, and its HUC 8 watershed. .......................................................................... 59

Table 15. Potential surface water management concerns at SECN parks. ................................... 65

Table 16. List of Indicators of Hydrologic Alteration and Environmental Flow Parameters 

from The Nature Conservancy’s IHA software manual (2007). ................................................... 67
x 

Table 17. Recommendations for SECN parks for future surface water monitoring needs. ......... 77
xi 

Appendices 

Page 

Appendix A – Surface Water Data Analysis Support Programs .................................................. 83

Appendix B – Streamflow Measurement Procedure .................................................................. 107

Appendix C- Sea Level Rise Scenarios ...................................................................................... 111

xiii 

Abstract 

The surface-water hydrology of the United States has been widely altered by natural and 

anthropogenic forces. Within the U.S. National Park Service’s (NPS) Southeast Coast Network 

(SECN), some of these alterations include the construction of dams, increases in urban 

development, stream channelization, erosion, and salt-water intrusion into freshwater marshes. 

This report summarizes a NPS-funded project that examined surface water trends and monitoring 

within eleven SECN parks. For many parks within the SECN, there is little information on 

surface water availability. For others, especially those located near a dam, long-term data sets are 

readily available through the U.S. Geological Survey (USGS). Data sources relevant to SECN 

parks were inventoried and analyzed to determine trends in streamflow and identify how 

anthropogenic influences, such as dams, have influenced surface water hydrology within or near 

each park. Many gages contain large gaps in data or have been discontinued. In some instances, 

no long-term data are available, which increases the uncertainty in trend analysis. For smaller 

parks within the network, automated gaging may not be necessary. However, for those parks in 

coastal areas and along major rivers prone to flooding, long-term monitoring is necessary to 

assess how the park may be affected by land-use changes and long-term influences of local and 

global climate change. To ensure park employees and researchers have adequate access to data 

and analysis tools, two computer programs are presented within this report that allow surface 

water data to be easily obtained and processed. 

xv 

Glossary of Terms 

Anthropogenic: Caused by human actions. 

Aquifer: Layer of water-bearing permeable rock, sand, or gravel capable of providing significant 

amounts of water. 

Catchment: The region draining into a river, river system, or other body of water. 

Cubic feet per second (cfs): A volume of water (measured in cubic feet) flowing in a unit of 

time (measured in seconds). 

Datum: A fixed reference point with known elevation. 

Evapotranspiration: Term used to describe the sum of evaporation and plant transpiration from 

the earth's land surface to the atmosphere. Evaporation accounts for the movement of water from 

sources such as the soil, canopy interception, and waterbodies. Transpiration accounts for the 

movement of water within a plant and the subsequent loss of water as vapor through stomata in 

its leaves. Evapotranspiration is an important part of the water cycle. 

Environmental Flow Component (EFC): A method that divides the hydrograph into high flow 

(>75th percentile) and low flow (<50th percentile). High flows are further divided into Large 

Floods (10 year recurrence), Small Floods (2 year recurrence) and High-flow Pulses (rise faster 

than 25% and fall faster than 10%). Low flows also include Extreme Low Flows (<10th

percentile). 

Fall line: A line connecting the waterfalls of nearly parallel rivers that marks a drop in land 

level. 

Flow duration curve: A cumulative frequency curve that shows the percentage of time that 

specified discharges are equaled or exceeded. 

Gumbel I distribution: A theoretical statistical distribution within the family of continuous 

probability distributions used to model the distribution of maximum or minimum events and in 

hydrology is useful for predicting the chance that an extreme event will occur. Equivalent to the 

Weibull distribution of a logarithmically transformed variable. 

Hydrologic Alteration Factor (HA): A measure of the hydrologic change from past conditions; 

the historical or pre-settlement is set to be the expected value and the recent value is set to be the 

observed value. The HA indicates, with one number, both the degree (percentage) and direction 

of change of each flow metric relative to the historical / presettlement values. Negative values 

indicate a decrease relative to historical / pre-settlement values; positive values indicate an 

increase. 

Hydrograph: A graph showing the water level or flow rate for a given point on a stream or in a 

well with respect to time. 
xvi 

Hydrologic Unit Code (HUC): A number corresponding to watershed boundaries established 

by the USGS in order to standardize watershed classification at local and national levels. 

Hyporheic: The area located beneath and lateral to a streambed where shallow groundwater and 

surface water mix. 

Hysteresis: A relationship between two variables that changes depending upon previous 

conditions (e.g., the relationship between stage and discharge for a rising tide may be different 

than for a falling tide).

Indicators of Hydrologic Alteration (IHA): A quantitative tool developed by the Nature 

Conservancy used to evaluate the impacts of changes to a hydrologic system 

(http://www.nature.org/initiatives/freshwater/conservationtools/). 

Log Pearson Type III distribution: A theoretical statistical distribution within the family of 

continuous probability distributions that describes the probability of occurrence of a given event 

and has been widely used to calculate flood re-occurrences. Equivalent to the gamma distribution 

of a logarithmically transformed variable. The default distribution used by the U.S. Geological 

Survey for flood studies. 

Measuring Point: A point accessible on or near a well that is used for measuring the depth to 

water. The water surface elevation is calculated as the difference between the measuring point 

elevation and the depth to water. 

Range of Variability Analysis (RVA): A method that divides the range of pre-impact data 

values. Delineation into three equal categories, for example, would result in parameters less than 

or equal to the 33rd percentile, parameters between the 33rd and 67th percentile, and parameters 

greater than or equal to the 67th percentile. The method calculates the expected frequency at 

which the post-impact values should occur in each category. A comparison of these data 

provides a pre- and post-impact measure of the hydrologic alteration between flow regimes. 

Regional skew coefficient: A measure of the asymmetry of the frequency distribution of a realvalued random variable, averaged over a region. When used for extreme hydrologic events, the 

distribution is normally taken to be the annual extreme. 

Return frequency: A measure of how often (on average) an event (precipitation, flood, etc.) 

will occur that is greater than some chosen value (e.g., 1, 2, 5, 10, 100 year). 

Saltwater intrusion: The invasion of fresh surface water or groundwater by saltwater. 

Seven-day flow: The average daily discharge over a week. 

Single-day flow: The average daily discharge over a day. 

Specific conductance: A measure of the ability of water to conduct an electrical current adjusted 

to a reference temperature. It is an indirect measure of the presence of inorganic dissolved solids, 

such as chloride, nitrate, sulfate, phosphate, sodium, magnesium, calcium, and iron. 
xvii 

Staff gage: A tool for measuring water level in a body of water. A staff gage is graduated in 

appropriate units and is placed so that a portion of the gage is in the water body at all times. 

Observers read the water stage off the staff gage. 

Rating curve: Relationship between depth and the amount of flow in a channel, or storage in a 

reservoir.

1 

Background 

Project Overview 

The Southeast Coast Network (SECN) contains twenty parks (Table 1), seventeen of which 

contain significant and diverse natural resources. In total, SECN parks encompass more than 

178,000 acres of federally managed land across North Carolina, South Carolina, Georgia, 

Alabama, and Florida. 

These parks span a wide diversity of cultural missions also, including four National Seashores, 

two National Historic Sites, two National Memorials, seven National Monuments, two National 

Military Parks, as well as a National Recreation Area, National Battlefield, and an Ecological 

and Historic Preserve. The parks range in size from slightly more than twenty to nearly 60,000 

acres, and when considered with non-federal lands jointly managed with SECN parks, the 

Network encompasses more than 242,000 acres1. 

SECN stream systems have been altered by human activities, including impoundments, 

channelization, lowering of water tables, increased runoff, pollution, sedimentation, recreation, 

and introduced species (including mussels, fishes, and aquatic plants). Many examples of effects 

on stream biota can be cited (Hackney and Adams 1992) and nearly all major stream systems 

have been channelized or dammed (Adams and Hackney 1992). In the Southeast, 144 major 

reservoirs have been built (Soballe et al. 1992) and one-third of all Florida Rivers have 

impoundments. Major hydropower facilities are located upstream of three of the six river parks 

in the network (CONG, HOBE, CHAT). 

Table 1. Southeast Coast Network (SECN) National Park units covered in this report. 

Alpha Code2 Park Unit 

CHAT Chattahoochee River National Recreation Area 

CONG Congaree National Park 

FOFR Fort Frederica National Monument 

FOMA Fort Matanzas National Monument 

FOPU Fort Pulaski National Monument 

FOSU Fort Sumter National Monument 

HOBE Horseshoe Bend National Military Park 

KEMO Kennesaw Mountain National Battlefield Park 

MOCR Moores Creek National Battlefield 

OCMU Ocmulgee National Monument 

TIMU Timucuan Ecological and Historic Preserve 

Surface water dynamics is ranked ninth among all of the potential vital signs evaluated by the 

SECN even though streamflow characteristics offer some of the most appropriate and useful 

indicators for assessing river ecosystem integrity and changes over time. The hydrologic output 

of a watershed is a function of land characteristics and human use, weather and climate 

conditions, urbanization and soil characteristics. Hydrologic variation plays a key part in 

 

1 Additional information can be found at http://science.nature.nps.gov/im/units/secn/index.cfm

2

 The NPS assigns each park unit a unique Alpha Code, which is used throughout this report. 
2 

structuring the biotic diversity within river ecosystems by controlling critical habitat conditions 

within the river channel, the floodplain, and hyporheic zones. Stream hydrology data provide key 

support data for vital signs indicators including water chemistry, stream Threatened and 

Endangered (T&E) species and fish assemblages, T&E amphibians and reptiles, wetlands, and 

riparian habitat. 

Population Changes 

Urbanization of natural areas is a growing concern. All of the parks, except for Horseshoe Bend, 

are located in counties that experienced population increases from 2000 to 2008 based on 

population data provided by the U.S. Census Bureau. The projected populations all showed 

population increases (Table 2). 

Table 2. Recent and projected populations for counties containing SECN parks3. 

Park County 2000 

Population 

2008 

Population 

Percent 

Change 

Projected Population 

CHAT Cobb, GA 607,747 698,158 14.9% 811,129 (2015) 

CHAT Forsyth, GA 98,407 168,060 70.8% 232,948 (2015) 

CHAT Fulton, GA 815,844 1,014,932 24.4% 832,751 (2015) 

CHAT Gwinnett, GA 588,450 789,499 34.2% 1,030,700 (2015) 

CONG Richland, SC 320,779 364,001 13.5% 425,960 (2030) 

FOFR Glynn, GA 67,568 75,884 12.3% 100,483 (2030) 

FOMA St. Johns, FL 123,148 181,540 47.4% 287,456 (2030) 

FOPU Chatham, GA 232,347 251,120 8.1% 307,472 (2030) 

FOSU Charleston, SC 309,974 348,046 12.3% 386,660 (2030) 

HOBE Tallapoosa, AL 41,802 40,773 -2.5% 44,567 (2025) 

KEMO Cobb, GA 607,747 698,158 14.9% 811,129 (2015) 

MOCR Pender, NC 41,082 51,314 24.9% 78,479 (2030) 

OCMU Bibb, GA 153,887 155,216 0.9% 155,240 (2015) 

TIMU Duval, FL 778,866 850,962 9.3% 1,147,189 (2030) 

TIMU Nassau, FL 57,663 69,835 21.1% 107,452 (2030) 

Climate Change 

The Intergovernmental Panel on Climate Change (IPCC) has provided projections and 

estimations on how climate change may impact water resources (Kundzewicz et al. 2007); 

however, understanding how these changes have influence at different regional scales is difficult 

and requires long-term monitoring (Brekke et al. 2009). It has been suggested that in raindominated catchments, such as the Southeastern United States, flow seasonality will increase. 

This will result in higher flows during the peak flow season and lower flows during low-flow 

seasons and/or longer dry periods (Kundzewicz et al. 2007). The timing of these events is also 

likely to change, but regional variation is also expected (Stewart el al. 2005; Hodgkins et al., 

2003; Knowles et al. 2006; Hodgkins et al. 2007). The large amount of uncertainty has led to a 

federal recommendation to increase the amount of tracking of water resources so that changes 

can be monitored more closely and water availability can be anticipated (Brekke et al. 2009). 

 

3

 Sources: Center for Quality Growth and Regional Development at the Georgia Institute of Technology, GeoPlan 

Center at the University of Florida, North Carolina State Demographics & Bureau of Economic Analysis, South 

Carolina Office of Research and Statistics, Office of Planning and Budget for Georgia, The Office of Primary Care 

and Rural Health, Alabama Department of Public Health, and The Alabama Rural Health Association. 
3 

For many of the analyses conducted in this report, as well as nationally recognized standards in 

estimating trends, it is assumed that future events (high-flows, low-flows, etc.) will occur at the 

same rate that they have historically. This assumption may not be correct if climate change, as it 

has been suggested, alters the frequency of these events (Brekke et al. 2009). If climate change is 

a driving force of the frequency and timing of the seasonality of flow, then current trends may 

need to be re-evaluated. 

The large amount of uncertainty associated with many of the projections of changes in water 

availability due to climate change (Brekke et al. 2009; Miller and Yates 2006) means that more 

data is likely needed before the direction and magnitude of the influence can be measured. Given 

the fact that there is not enough data to determine the trends of surface water flow within the 

boundaries of some NPS lands, the current recommendation to increase monitoring is a prudent 

measure that has direct benefits to the parks themselves, as well as to society as a whole. Climate 

Change and Water Resource Management: A Federal Perspective4 provides an in-depth 

interagency report prepared by the USGS, USACE, Bureau of Reclamation, and NOAA that 

explores water management strategies in response to climate change. Much of the information 

contained within it is beyond the scope of this report; however, the authors emphasize the 

importance of monitoring and the central role it plays in future planning and decision making. 

Project Objectives 

This project seeks to develop a protocol, and to collect and analyze existing data to determine the 

status and trends of water quantity in surface waters upstream, bordering, or within park 

boundaries; and also determine the frequency, duration and magnitude of peak flow events for 

eleven parks within the Southeast Coast Network. 

Specific objectives of this report include: 

1. Summarize and present the results of a literature review on streamflow discharge 

monitoring efforts relevant to SECN parks, including information about parameters 

collected/measured, instrumentation used, and existing protocols. 

2. Identify and catalog gaging stations and other data sources relevant to SECN parks - 

a. Including (but not limited to): site ID, description, and relevant parameters. 

b. History and frequency of measurements and location information (e.g. UTM 

coordinates). 

3. Incorporate data acquired from web-based program archives or other sources such as 

various State and Federal programs (e.g. USGS) into NPS holdings. 

4. Analyze existing data in order to address the following long-term monitoring objectives: 

a. Determine the status and trends of water quantity in surface waters upstream, 

bordering, or within park boundaries. 

 

4 http://pubs.usgs.gov/circ/1331/
4 

b. Determine the frequency, duration, and magnitude of peak flow events. 

c. Examine surrounding landscape to quantify landcover types within and 

surrounding SECN NPS holdings. 

5. Identify significant data gaps including spatial distribution and temporal coverage and 

where possible, provide recommendations for filling current gaps within parks that lack 

adequate monitoring. 

6. Develop a long-term monitoring protocol for SECN streamflow discharge monitoring 

that utilizes existing data sources and follows NPS and I&M program guidance for 

protocol development. 

7. Provide data analysis software tools for NPS personnel to facilitate the examination of 

specific questions about surface water hydrology that may arise in the future. 

8. Provide projections for storm surge and sea level rise that could affect coastal parks. 
5 

Literature Review 

This section examines previous publications related to the surface-water hydrology within or 

near SECN parks, focusing on the water quantity issues at these facilities. The purpose of this 

literature review is to summarize major studies that address surface water quantity in SECN 

parks. A list of surface water gages within or near SECN parks is provided as Table 3. 

Much of this information is typically found within the context of water quality rather than 

quantity. With few exceptions, little research has been done to assess the surface-water 

conditions in many of the NPS SECN parks with respect to water quantity. Although several 

studies have examined water quality, few have addressed the issue of surface water quantity and 

trends. In spite of this, studies emphasize the inextricable link between water quality and water 

quantity (Figure 1). 

Figure 1. Conceptual model of factors influencing freshwater ecosystems (from Baron et al., 2002). 
6 

Table 3. Surface water gages within or near SECN parks and periods of record for discharge and gage 

height.[Bolded park names indicate gages located within park boundaries; NA, data not available] 

Park Gage # Name Discharge 

Period of Record 

Gage Height 

Period of Record 

CHAT 02335450 Chattahoochee River above 

Roswell, GA 

7/7/1976 Present 10/1/1993 Present 

CHAT 02335815 Chattahooche River below 

Morgan Falls Dam, GA 

10/2/2000 Present 10/2/2000 Present 

CHAT 02334430 Chattahooche River at Buford 

Dam near Buford, GA 

1/27/1942 Present 10/1/1993 Present 

CHAT 02335000 Chattahoochee River near 

Norcross, GA 

1/1/1903 Present 10/2/1993 Present 

CHAT 02336000 Chattahoochee River at 

Atlanta, GA 

8/1/1928 Present 10/1/1986 Present 

CHAT 023358685 Sewell Mill Creek at GA 120, 

near Marietta, GA 

4/28/2007 Present 4/28/2007 Present 

CONG 02169670 Cedar Creek below Myers 

Creek near Hopkins, SC 

11/13/1980 9/30/1985 NA NA 

CONG 02169625 Congaree River at Congaree 

NP near Gadsden, SC 

NA NA 10/1/1984 Present 

CONG 02169672 Cedar Creek at Congaree NP 

near Gadsden, SC 

NA NA 8/27/1985 Present 

CONG 02148315 Wateree River below 

Eastover, SC 

7/30/1968 Present NA NA 

CONG 02169570 Gills Creek at Coloumbia, SC 10/1/1966 Present NA NA 

CONG 02169500 Congaree River at Columbia, 

SC 

10/1/1939 Present NA NA 

FOFR 02226178 East River at Mayors Pt 

Terminal Brunswick, GA 

NA NA 11/16/2000 11/2/2003 

FOFR 022261792 Brunswick River, Colonels 

Island, near Brunswick, GA 

NA NA 10/1/2000 11/2/2003 

FOFR 02226180 Brunswick River at St. Simons 

Island, GA 

NA NA 11/18/1998 6/17/2009 

FOMA 02244040 St. Johns River at Buffalo Bluff 

near Satsuma, FL 

10/2/1992 Present 10/1/1990 Present 

FOPU 02198980 Savannah River at Fort 

Pulaski, GA 

NA NA 10/10/1987 12/4/2005 

FOPU 021989773 Savannah River at usace dock 

Savannah, GA 

NA NA 10/1/2008 3/4/2009 

FOPU 02198840 Savannah River near Port 

Wentworth, GA 

NA NA 6/17/1987 9/30/2005 

FOSU 021720677 Cooper River at Filbin Creek 

at North Charleston, SC 

NA NA 4/4/1997 Present 

FOSU 02172100 Charleston Harbor at Ft 

Sumter near Mt Pleasant, SC 

NA NA 10/8/1992 9/30/2005 

FOSU 02172053 Cooper River at Mobay near 

N. Charleston, SC 

NA NA 10/1/1986 Present 

FOSU 021720696 Wando River at Cainhoy, SC 5/1/2004 4/30/2005 5/1/2004 4/30/2005 

FOSU 021720698 Wando River abover Mt 

Pleasant, SC 

NA NA 7/30/1992 Present 

FOSU 021720709 Cooper River at U.S. Hwy 17 

at Charleston, SC 

NA NA 4/11/1997 8/18/2005 
7 

Table 4. (Continued) 

Park Gage # Name Discharge 

Period of Record 

Gage Height 

Period of Record 

FOSU 021720710 Cooper River at Customs 

House (Aux) at Charleston, 

SC 

NA NA 10/30/1986 10/22/2002 

FOSU 021720711 Cooper River at Customs 

House at Charleston, SC 

(Tide) 

NA NA 8/7/1984 Present 

HOBE 02414715 Tallapoosa River near New 

Site, AL (Horseshoe Bend) 

11/15/1985 Present 11/14/1985 Present 

HOBE 02414500 Tallapoosa River at Wadley, 

AL 

10/1/1923 Present 10/1/1971 Present 

KEMO 02336968 Noses Creek at Powder 

Springs rd, Powder Springs, 

GA 

7/14/1998 Present 7/15/1998 Present 

KEMO 02393377 Butler Creek at Mack Dobbs 

rd, near Kennesaw, GA 

NA NA 4/13/2007 Present 

MOCR 02105769 Cape Fear river at Lock #1 

near Kelly, NC 

7/1/1969 Present 1/15/1974 9/30/2008 

MOCR 02108566 Northeast Cape Fear river 

near Burgaw, NC 

11/14/2003 12/12/2005 8/12/1999 6/28/2009 

MOCR 02107544 Black River near Currie, NC 3/1/2004 12/13/2005 3/5/2004 12/13/2005 

OCMU 02213050 Walnut Creek near Gray, GA 10/1/1961 4/26/1994 NA NA 

OCMU 02213000 Ocmulgee River at Macon, GA 1/02/1893 Present 10/1/1992 Present 

OCMU 02210500 Ocmulgee River near 

Jackson, GA 

5/18/1906 Present 3/12/1987 Present 

TIMU 02231289 Nassau River near Hedges, 

FL (at HWY 17) 

6/10/1983 9/30/2004 4/19/1983 9/30/2004 

TIMU 02246500 St. Johns River at 

Jacksonville, FL 

10/1/1971 Present 10/1/1971 Present 

CHAT: Chattahoochee National Recreation Area 

The Chattahoochee River National Recreation Area (CHAT) is made up of 6,800 acres of mixed 

pine/hardwood forests and wetlands that buffer 48 miles of the Chattahoochee River. Surface 

water bodies within the park include the following: Chattahoochee River and associated 

tributaries, Bull Sluice Lake, Sibley Pond (in the Cochran Shoals unit), and Island Ford Pond. 

Upstream of the park is Buford Dam that impounds Lake Lanier. Water released from Lake 

Lanier through Buford Dam into the Chattahoochee River flows from the lower strata of the lake 

(hypolimnion during the stratification period). The dam also regulates the flow within CHAT. 

Current regulations require that the flow be 750 cfs at the confluence of the Chattahoochee River 

and Peachtree Creek; however, beginning last year (2008) Georgia EPD allowed this standard to 

be lowered by 100 cfs during droughts to preserve storage in Lake Lanier. 

The dam moderates peak and low flows to prevent floods and manage droughts. The streamflow 

data within CHAT is well documented by U.S. Geological Survey (USGS) with six gaging 

stations within the park (Table 3). In 2000, Kunkle and Vana-Miller reviewed the surface water 

hydrology, discharge, and water demand for the Chattahoochee. Kunkle and Vana-Miller (2000) 

also provided estimates of flood frequencies for all gages within the park and they noted the 

strains placed on CHAT during drought periods. Proposed management actions within their plan 
8 

includes evaluating the effects of the tri-state water allocation formula, but no specific 

recommendations on flow were made. 

CONG: Congaree National Park 

Congaree National Park is made up of 24,180 acres of currently owned land, and 26,776 acres of 

authorized area. The park consists of old-growth bottomland forests along the Congaree River, 

and comprises an extensive floodplain ecosystem. The park averages 100,000 visitors per year 

and lies in the floodplain of the Congaree River in the Coastal Plain physiographic province of 

South Carolina. The upstream watershed includes over 5 million acres (Knowles 1996) and 

major flood events along the Congaree River occur, on average, 10 times per year. Ninetypercent of CONG is annually flooded by major events (Knowles 1996). 

The parks surface is composed of freshwater wetlands and forested wetlands. Surface water 

resources within and near CONG include the Congaree, Wateree, and Santee Rivers; Congaree, 

Wateree, and other swamps and wetland areas; Cedar, Toms, Gills, Congaree, and many other 

creeks, oxbows, and other natural lakes and ponds (see Knowles et al. 1996 for complete list). 

Maintaining a functioning floodplain ecosystem is dependent upon the timing, duration, 

magnitude and extent of flooding from the Congaree and Wateree Rivers. 

Many studies have been conducted on surface water and groundwater characteristics throughout 

the park. Numerous investigations have been conducted to elucidate how hydrologic forces 

influence the biotic and abiotic components related to the ecosystem function within CONG. For 

a detailed literature review see Graf and Stroup (2006). For the purposes of this report, we 

highlight several relevant surface water investigations and summarize findings from reports 

published subsequent to the review by Graf and Stroup (2006). 

Patterson et al. (1985) studied the effects of hydrology on vegetation distribution throughout 

Congaree NP and found that the level of the shallow aquifer that exists beneath CONG is related 

to the stage of the Congaree River. General information on relationships between gage height 

and what happens at CONG is given in this report, although the information is more qualitative 

in many respects compared to more current reports. This report also gives details concerning the 

connection between flood stage on the Congaree River west of Wise Lake to the Congaree River 

at Columbia and Cedar Creek at Wise Lake. In a similar report (Speiran et al. 1985), further 

details are given about the decreases in discharge after the construction of Lake Murray and 

mapped details of the areas of inundation within the park that occur 1%, 10%, and 75% of the 

time for a given year are illustrated. Similar to Patterson et al. (1985), the relationship between 

the Congaree River at Columbia, the Congaree River west of Wise Lake, and Cedar Creek is 

given. Additionally, further information about the average number of times per year for given 

flooding effects is catalogued as well as the relationship between flood stages and groundwater 

levels. 

Merdun (2003) conducted a flood analysis on CONG to achieve three goals: 1) define flood 

magnitudes based on upstream gages; 2) determine the lag-time and peak differences in upstream 

discharge and discharge at CONG; and 3) use regression analysis to find a relationship between 

upstream rain gages and CONG discharge. Data were used from gaging stations found on the 

Congaree River, Wise Lake, Rail Road, Saluda River, Broad River, and Wateree River. 

Merdun’s (2003) analysis illustrated that although there was substantial amount of data available 
9 

from upstream gaging stations, he was unable to find a relationship between the discharge at 

CONG and the upstream gages. This makes prediction of flood events somewhat difficult within 

the Park based on these models. However, several parameters were not included in the models 

including infiltration, evapotranspiration, interception, soil characteristics, channel length and 

slope, which may improve the predictive ability of the model. The author also pointed out that 

substantial differences in the topography and forest structure between CONG and those upstream 

might account for absence of predictive ability of the models. 

Plewa and Graf (2005) examined the hydrologic variation of CONG and connected it to the 

various steam gages present along the Congaree River. They concluded that the Broad River was 

the primary determinant of hydrology within CONG and contributes nearly two-thirds of the 

flow of the Congaree River. By contrast, the Broad River contributes only one third of the flow 

to the Congaree. This report also details lag-time effects of dam releases from Par Shoals Dam 

on the Broad River as well as outlining how stage levels on the Congaree influence flows on 

creeks within the park. 

Detailed geospatial inundation modeling was conducted by Graf and Meitzen (2006) to provide a 

GIS model for various river flows and floodplain inundation depths. Their analysis utilized the 

Hydrological Engineering Center River Analysis System (HEC-RAS) to process and integrate 

geospatial data with streamflow models. This resulted in an interactive GIS model that is able to 

examine different river fluctuations and predict how they impact resources within CONG. Their 

work suggests that the Saluda Dam operations do influence flood hydrology of the Congaree 

River, but that the effect is variable. Therefore it would be difficult to assess how the Saluda dam 

operation would be remedied under re-licensing. 

Conrads (et al. 2008) conducted a very detailed analysis of the effects of the Saluda dam on the 

surface- and ground-water hydrology of the CONG floodplain. The impetus for this investigation 

was, in part, due to FERC re-licensing of the Saluda Dam that resulted in a temporary 

modification of streamflow pattern while the backup dam was being constructed. According to 

the authors, it was a common perception among hydrologists and ecologists that the Saluda Dam 

had significantly reduced the frequency and magnitude of peak flows of the Congaree River. 

Their report concluded that peak flow reductions after the construction of Lake Murray 

were likely the result of climatic variability and decrease (or absence) of large floods since 

1930. An analysis of dam effects on daily gage height on the Congaree River showed that 

gage height was lowered from December to May, but low gage heights from July to 

November were raised. The authors concluded that dam operation has a greater effect 

within the riverbanks of the Congaree than on the floodplain. Therefore, frequency of 

inundation within the park is more likely to be a result of flows from the Broad river.  

Although there is an exhaustive amount of literature on the hydrology of CONG, several data 

gaps exist and park personnel have expressed interest in increasing the amount of monitoring and 

data collection in several locations. These include increased monitoring along Tom’s Creek, 

establishment of gages within new land acquisitions on the eastern end of the park, and data 

collection along the U.S. Highway 601 corridor to enable predictions to be made concerning the 

influence of new construction on park hydrology. Park personnel also expressed additional 

concern over data that would be necessary to assess any potential impacts that may result from 

the re-licensing of the Wateree Dam and the construction of a nearby coal ash landfill. 
10 

FOFR: Fort Frederica National Monument 

Fort Frederica National Monument is located on 241 acres of marsh and upland on St. Simons 

Island, Georgia. The marshland takes up approximately 150 acres. Aside from the standing water 

in the marshland, the Frederica River runs adjacent to the park. St. Simons Island is a part of 

system of barrier islands that parallel the Atlantic and Gulf coasts from Maine to Texas. The 

primary driver of surface water availability at FOFR is tide fluctuation. The tides affect the water 

levels and salinity in the marshes, creeks and rivers. Surface water quality data were collected, 

reported, and summarized in NPS (1998a), however no literature assessing water quantity is 

available. 

However, Bratton (1985) assessed the vegetation history of Fort Frederica that indicate that 

many extensive ponds and marshes once existed at FOFR, but are much smaller now or no 

longer present. Changes in the extent of marshland surrounding FOFR undoubtedly impact 

maximum gage height during heavier storm events such as hurricanes. 

FOMA: Fort Matanzas National Monument 

Fort Matanzas consists of approximately 300 acres of land and the associated Castillo de San 

Marcos consists of approximately 18 acres. The parks consist of 15 percent wetland, marshland, 

and estuarine waterway. The historic Spanish fort on Rattlesnake Island and a Visitor Center 

attract roughly one million visitors per year. 

Surface water resources in the FOMA/CASA watershed include the Atlantic Ocean; portions of 

the Intracoastal Waterway; the Tolomato, Matanzas, and San Sabastian Rivers; the St. Augustine 

and Matanzas Inlets; Pellicer Creek and other smaller creeks and numerous tidal swamps, 

marshes, and estuaries. Many of these water resources are influenced by tidal flow and contain 

fresh and saline waters in transition. No relevant literature on surface water quantity is available.

FOPU: Fort Pulaski National Monument 

Fort Pulaski National Monument is located on Cockspur Island in the Southeastern Coastal Plain 

physiographic region and contains approximately 5400 acres of surface water marshes and 

wetlands. Located at the mouth of the Savannah River near Savannah, GA, it receives 

approximately 500,000 visitors each year. 

Surface water bodies, aside from the Savannah River, include two small ponds for mosquito 

control and the moat that encircles the fort. There are also many man-made dikes and drainage 

ditches located near the Fort. Other surface water features in the vicinity of the park include the 

Atlantic Ocean; Intracoastal Waterway; Wassaw Sound; the Savannah, Bull, Wilmington, and 

many other rivers; Oyster, Tybee, Fields, and numerous other creeks and cuts; a few canals; and 

many marshes, tidal swamps, and estuaries. Most of these surface-water resources are influenced 

by tidal flow and contain fresh and saline waters in transition (National Park Service, 1999) 

McFarlin and Alber (2005) conducted a report to assess the coastal water resources at FOPU, 

however, their report focuses primarily on water quality, not quantity and contains little 

information relevant to the objectives of this report. However, numerous water and coastline 

assessments have been conducted in and around Fort Pulaski with the primary goal of predicting 

how the deepening of the Savannah River shipping channel will influence the shoreline 

(Alexander 2008), water level, and salinity in the region (Conrads et al. 2006). According to 
11 

Tiner (1977), approximately 24,000 acres of tidal freshwater wetlands were intact within the 

lower Savannah River in the late 1960’s, however much of that has been greatly reduced by 

saltwater intrusion. 

The Georgia Ports Authority and the United States Army Corps of Engineers was required to 

conduct an environmental impact assessment (EIA) in order to understand how deepening one of 

the busiest shipping channels in the world would influence ecological and hydrodynamic 

processes (Conrads et al. 2006). The result of these studies generated a three-dimensional model 

designed to simulate changes in water levels and salinity, and a marsh-succession model to 

assess how plant distribution may be influenced in the tidal marshes as result of the channel 

deepening. Although these studies did not take place on Fort Pulaski, much the information is 

relevant and includes analyses of data collected at Fort Pulaski gaging stations in addition to 

others upstream. 

Alexander (2008) determined that although there has been substantial alteration of the shoreline 

of Cockspur Island, there was not a direct correspondence between the erosion of the shoreline 

and deepening of the shipping channel. However, he cautioned that the short time period over 

which the comparisons of shoreline change were made might make it difficult to find statistically 

significant changes. Significant alteration of the shoreline, due to the deepening of the channel, 

could have substantial impacts on the salinity and availability of surface water on Cockspur 

Island although many of these effects are largely unknown (Alexander 2008). 

In the summary provided by Conrads et al. (2006), USGS streamflow, water level, and specificconductance river gages on and around Fort Pulaski were used to try and understand freshwater 

inflows, tidal water levels, and specific conductance to increase their ability to create a marsh 

succession model. In the process, nearly 75 years of flow and estuary water level data were 

analyzed, including data collected at Fort Pulaski. High (95th percentile) streamflows generally 

peak between 30,000 – 50,000 cfs from January to May and then remain relatively stable 

between 20,000 – 30,000 cfs from June through December. The majority of the flow is dictated 

by the amount of water released upstream from Thurmond Dam near Augusta, GA. Many of the 

specific results from this study are beyond the scope of this review, however, the summary 

provided by Conrads et al. (2006) is a valuable resource that allows for a detailed analyses of 

surface water flow and depth data within the Savannah River Harbor.

FOSU: Fort Sumter National Monument 

Fort Sumter National Monument is a small island located in the mouth of Charlestown Harbor. 

Surface water resources in the FOSU study area include the Atlantic Ocean; portions of the 

Intracoastal Waterway; Charleston Harbor and other bays and coves; the Cooper, Ashley, and 

Wando Rivers; Shem, James Island, Hobcaw, and numerous other creeks and cuts; a few 

impoundments; and many marshes, tidal flats, and estuaries. Many of these water resources are 

influenced by tidal flow and contain fresh and saline waters (National Park Service, 2001b). 

Adequate attention has been given to reporting the surface water quality in and around FOSU 

(National Park Service, 2001b). Although there is some analysis of streamflow contained within 

this report, a comprehensive analysis of surface water quantity is lacking. 
12 

HOBE: Horseshoe Bend National Military Park 

Horseshoe Bend National Military Park is made up of 2,040 acres of mixed hardwood forest. 

Most of the park is upland, with approximately ten percent of the area representing wetlands. A 

portion of the forests is recovering farmland. There are many open fields that commemorate 

historic battlefronts and the park averages 100,000 visitors per year. 

Surface water bodies at the park include the Tallapoosa River and Whale Creek. Surface water 

resources in the HOBE study area include the Tallapoosa River; Emuckfaw, Timbergut, 

Hillabee, Dobbs, and numerous other creeks; the northern areas of Martin Lake and other 

reservoirs; and many ponds and springs (National Park Service, 1997b). 

Adequate attention has been given to reporting the surface water quality in and around HOBE 

(National Park Service, 2001b). Although there is some analysis of streamflow contained within 

this report, a comprehensive analysis of surface water quantity is lacking. 

KEMO: Kennesaw Mountain National Battlefield Park 

Kennesaw Mountain National Battlefield Park is located in the Allatoona Mountain Range and 

consists of approximately 3000 acres of mixed hardwood pine forest and open fields. Less than 

ten percent of the park is considered wetlands. Multiple creeks are located within the park 

including John Ward Creek, Noses Creek and Allatoona Creek, which originate outside the park 

boundaries in metropolitan Atlanta. Kennesaw Mountain is located in the northern portion of the 

park, while other portions of the park are bounded and intersected by suburban developments. 

The park receives approximately 1.5 million visitors per year (includes passing traffic). 

No quantitative information about surface water was found for this park. 

MOCR: Moores Creek National Battlefield 

Moores Creek National Battlefield is located 20 miles northwest of Wilmington, North Carolina, 

and averages approximately 60,000 visitors per year. The park consists of 87.75 acres of forest, 

creek, wetland, and open fields on the Coastal Plain province of North Carolina. Moores Creek is 

the only significant stream within the park’s boundaries and drains approximately 85 mi2 at the 

section of the creek within MOCR. Moores Creek is a third order blackwater stream that drains 

into the Black River. Although Moores Creek is in the vicinity of the park is a freshwater system, 

it is influenced by tides from the Cape Fear River (Mallin and McIver 2007). 

Freshwater and forested wetlands make up approximately 12-15 acres of MOCR. It is speculated 

that historically the park used to be a wet pine savannah that was drained and converted to a 

meadow (Mallin and McIver 2007). Currently, MOCR is working on a 4.5-acre wetland 

restoration project in the middle of the park called the “savannah”, in an area that generally has 

standing water. Surface water resources near the park include Black River; Moores Creek, Colly 

Creek, Lyon Creek; Big Branch, Bear Branch, Deer Valley Branch; Long Bay, Flat Bay, Black 

Bay; and other small creeks, marshes, and swamps (National Park Service, 1997c). 

Mallin and McIver (2007) provide a summary of hydrology affecting MOCR and report that 

Moore’s Creek overflows its banks annually and longer floods tend to occur during hurricanes 

and El Niño years. Maximum elevations of the water surface range from 12 ft above mean sea 

level for a two-year storm up to 32 ft for a 100-year storm (USACOE 2000). For storms 
13 

occurring on a two year frequency, the estimated water velocity at the stream bank is 1.0 ft/sec 

and increases to 1.5 ft/sec for the 100 year frequency storms (USACOE 2000). Maximum 

discharges are reported as 1,150 CFS for the two-year frequency storm and increase to 5,940 

CFS for the 100-year storms (USACOE 2000). MOCR has also been adversely affected by 

several hurricanes in the past, including Hurricane Fran in 1996, Bonnie in 1998, and Floyd in 

1999 (Mallin and McIver 2007). Based on conversations with NPS personnel, flooding due to 

Hurricane Floyd was the most extreme within the park since 1946 (Mallin and McIver 2007). 

OCMU: Ocmulgee National Monument 

Ocmulgee National Monument is located on the Fall Line, near Macon, GA. The 702-acre park 

is surrounded by urban and suburban development. Roughly 300 acres of the park are classified 

as emergent wetlands. Surface water resources in the area include the Ocmulgee River; Walnut 

Creek, Swift Creek, Town Creek, and numerous other creeks; Edwards, Club, Nelsons, and other 

impounded lakes and ponds; and swamps and wetlands (National Park Service, 2001a). Like 

many other NPS lands, a comprehensive water quality analysis was conducted for OCMU 

(National Park Service, 2001a) that included some flow analysis, but a comprehensive flow 

analyses is lacking. 

TIMU: Timucuan Ecological and Historic Preserve 

Timucuan Ecological and Historic Preserve was established in 1988 and covers approximately 

46,000 acres consisting of Fort Caroline National Memorial, the Theodore Roosevelt Area, 

Kingsley Plantation, and Cedar Point. The make-up of the park is roughly 70 percent salt marsh 

and estuary, with mixed forested uplands. 

There is limited freshwater at Timucuan. Fort Caroline has Spanish Pond and nearby Lake 

Timucuan, which are influenced by fresh and saltwater (brackish) inputs. Rivers include St. 

Johns River and Nassau River. There are many saltwater creeks, estuaries, and the Intracoastal 

Waterway runs through the park. Surface water resources in the area include the Atlantic Ocean, 

portions of the Intracoastal Waterway, St. Johns, Fort George, Nassau, South Amelia, Rivers; 

Dunn, Clapboard, Browns, Cedar Point, and Edwards Creeks; Sample, Clapboard, and other 

swamps and marshes; interconnected lakes and lagoons; and some small impoundments. Many 

of these water resources are influenced by tidal flow and contain fresh and saline waters in 

transition (National Park Service, 2000). Barlow (2003) describes the landward flow of saltwater 

and its intrusion into coastal freshwater aquifers using several case studies. 

Water quality analysis was conducted for TIMU (National Park Service, 2000) that included 

some flow analysis, but comprehensive flow analyses are lacking. 

Summary 

There are many factors affecting freshwater ecosystems and surface water flow regime is among 

the most important (Figure 1). Understanding the characteristics of flow regimes is important to 

understanding changes in stream biologic communities, channel geomorphic conditions and 

protecting of the large number of historical structures found on or near stream or river 

floodplains within the network. Unfortunately, very little comprehensive information and 

analysis is readily available for many of the parks containing substantial surface water resources. 

For some parks, information is available for analysis; however, characterization of many of the 
14 

flow regimes appears to be lacking or unpublished (e.g. HOBE). Analysis of much of the 

available data is provided in subsequent sections of this report. 

Coastal parks, as well as inland parks (e.g. CONG), within the SECN are susceptible to 

hydrologic damage due to large storm events such as hurricanes and will likely be affected in the 

future by changes in sea level and salinity within tidal marshes (Conrads et al. 2006). For both 

inland and coastal parks, implementing a long-term monitoring program is important for 

assessing current and historical trends to adequately plan for the future.
15 

Surface Water Quantity Monitoring and Data Analysis 

Protocols 

Surface water refers to freshwater and near-coastal waters that occur on the Earth’s surface. This 

includes waters collecting on the ground or in a stream, river, lake, sea or ocean, as opposed to 

groundwater, which is found below the ground surface. For most purposes, two types of data are 

of interest; stage and discharge. Stage refers to the elevation of the water surface, while 

discharge refers to the rate of water flow in a channel past a point. 

Stage 

Stage is a critical surface-water monitoring variable in surface water systems. This is important 

in rivers and streams, as well as in estuaries and near ocean systems because water movement is 

dominated by ocean tides. Stage is also critical in slow-moving aquatic systems such as lakes and 

wetlands. Stage is also important for determining discharge (streamflow) in streams and rivers. 

Stage can be determined using either manual or automated measuring devices. A standard 

manual device is the staff gage, which is a graduated marker placed vertically in the water so that 

the water level can be read visually. The marker should be placed at a location suitable for 

viewing under a wide range of water conditions. In cases where the site is flooded at high water, 

then a second staff gage can be placed at a nearby location that is suitable for reading during 

high-water conditions. Another gage may be required during extreme-low conditions if the 

primary measurement device is not placed in the deepest part of the hydrologic feature. 

Automated readings can be collected using a variety of technologies, including pressure 

transducers, vibrating wire sensors, Doppler level indicators, and capacitance probes. These 

sensors are commonly connected to a data acquisition system that collects and stores the data. 

Stage measurements should be taken frequently enough to capture the maxima and minima of 

hydrologic variation. For slowly changing systems, the measurements may be taken daily or 

even weekly, such that the magnitude of the change does not exceed one cm. For tidal systems 

(or systems with pronounced daily cycles) hourly data would be desired. 

Extreme observations should be collected whenever possible, as the highest or lowest 

observations are critical when trying to determine statistical extremes. Annual maxima and 

minima should be collected, if possible. 

Spatial variation is important and should be recorded in locations where large changes in stage 

may be present, such as in isolated water bodies. The time lag between peak and low stages 

should be determined for these systems. 

Discharge 

Discharge is more appropriate for moving waters, such as streams and rivers. The accurate 

measurement of discharge is often resource intensive, requiring significant labor to obtain a 

single measurement. A stream cross-section is established, and flow velocities are measured 

across the section. The total flow, or discharge, is calculated using the sum of the product of the 

velocity and the incremental area. The discharge is related to the stage at the time of the 

measurements, and the relationship between stage and discharge is characterized using the rating 
16 

curve. The rating curve is then used to establish a time series of discharges using the time series 

of stages. For the purposes of this report, the majority of the available relevant data is discharge, 

so these data were analyzed to assess trends. 

In coastal systems with significant tidal movement, the relationship between stage and discharge 

is not unique. The rising and falling stages will display hysteretic relationships that must be 

established over a wide range of conditions. In these cases, an automated velocity sensor can be 

deployed to better establish the relationship between stage and discharge. In the absence of 

automated systems of data collection, a stage-flow curve can be generated to make inferences 

about the relative flows at different stages. For information on how to create a stage-flow curve, 

see Appendix B. 

Inventory and Flow Analysis 

This section combines land cover, water inventory, and flow analysis for the SECN. Because of 

the important and established linkages between basin land cover and streamflow, land cover was 

included as a part of this analysis. Land cover analysis for each park is reported first within each 

section followed by the water inventory and flow analysis. Maps of land cover types (including 

dam and gage locations) and tables of percentages of each type are reported at 3 spatial scales for 

each property: park boundary, 5-km buffer, and HUC watershed level. The water inventory 

provides a summary of relevant gage data and flow analysis where data were available. 

The land cover analysis was created using ArcMap version 9.3. The National Land Cover Data 

(NCLD) 2001 layers were utilized, downloaded with the Geospatial Data Gateway available 

online at http://datagateway.nrcs.usda.gov/GatewayHome.html. The land cover data is 

differentiated into 16 different classes as follows: open water, perennial ice/snow, developed 

open space, developed low intensity, developed medium intensity, developed high intensity, 

barren land, deciduous forest, evergreen forest, mixed forest, scrub/shrub, grassland/herbaceous, 

pasture/hay, cultivated crops, woody wetlands, and emergent herbaceous wetland. A detailed 

description of each class is available online at http://www.epa.gov/mrlc/definitions.html. 

Each cell in the GIS layer represents 30m by 30m of ground data. The tables were created to 

show the land cover within the park, a 5-km buffer around the park and the entire HUC 

(Hydrologic Unit Code) 8 watershed encompassing the park. This was done to illustrate how 

landcover upstream and surrounding the park may affect flow characteristics within the park. 

This section provides an inventory of gages at or near SECN parks and lists the dates of available 

data for flow history (Table 3). The majority of this information was collected via automated 

data logging available through the USGS website (http://waterdata.usgs.gov/nwis/rt) and 

analyzed using the program RIVER2 (Dowd 2009) A detailed description of this program is 

provided in Appendix A). 

Trend analysis was performed for non-coastal parks with available discharge data. These parks 

included: CHAT, CONG, HOBE, KEMO, and OCMU. For each park, graphs of the average 

daily flow and flow duration were created if data were available. High and low flows were 

analyzed with the Log Pearson III estimation technique to estimate the return interval for high 

and low-flow events (regional skew coefficients were applied when long-term data was lacking). 
17 

The Log Pearson III distribution fits frequency distribution data in order to predict the return 

period of high-flow and low-flow events of a particular magnitude. 

The Log Pearson III technique is the standard technique used by federal agencies and has been 

shown to produce unbiased estimates as long as adjustments to the expected probability (regional 

skew coefficients) have been appropriately employed (Beard 1974). For some streams, data is 

only available for recent years and therefore no flood record exists for that site. In this instance, 

other nearby stations were used to create nationally recognized regional skew coefficients to 

substitute for the lack of information in a particular area. In these cases, in order to account for 

the small sample size of particular gage, regional data were used as a substitute to make 

predictions about the return frequency of particular flow events. Other methods of analysis can 

be applied and examined (e.g. Gumbel I and Gumbel III) using RIVER2 (see Appendix A), 

however these methods generally do not reduce uncertainty any more than the Log Pearson III 

method (Beard 1974). 

In the event streamflow was altered due to dam construction, the data were analyzed pre- and 

post-dam construction if preliminary analysis suggested a change in flow characteristics. This 

enabled the comparison of changes in flow parameters. Typically, if a park contained more than 

one gage, only data from one gage were analyzed unless multiple streams with gages influence 

the park. For coastal parks heavily influenced by tides, flow data were not analyzed and the gage 

height is reported instead of flow, since tidal action prevents meaningful analysis of flow. 

Maximum, minimum, and mean gage heights are reported where available. However, many 

USGS stations only report one parameter (often mean height), which may be of little use if 

understanding maximum heights during surge events is desired. 

For more information on various flow analysis techniques, the following web sites may be 

useful: 

http://www.epa.gov/waterscience/models/dflow/flow101.htm#methods

http://water.oregonstate.edu/streamflow/analysis/floodfreq/index.htm

CHAT: Chattahoochee National Recreation Area 

Within the recreation area approximately 17% is classified as open water, but the dominant land 

cover class is deciduous forest (Figure 2; Table 4). Low intensity development and developed 

open space dominates much of the land cover within a 5-km buffer of CHAT. At the watershed 

level, however, deciduous forest is the dominant land cover class (Table 4). 

There are currently five USGS gaging stations located within CHAT (Table 3), the oldest of 

which is located near Norcross, GA, and represents data going back to 1903. Prior to the 

construction of Buford Dam and the creation of Lake Lanier, peak-flow events exceeded 30,000 

cfs on several occasions between 1915 and 1946 (Figure 3). After the construction of the dam, 

peak flow events have rarely exceeded 10,000 cfs (Figure 3). As would be expected, the 

construction of the dam decreased the magnitude of all peak-flow events downstream within 

CHAT (Figures 4-5). Also as expected, the 7-day low-flow magnitude increased following the 

construction of the dam, although the increase was not substantial (Figures 6-7). 
18 

Similarly, flow duration curves indicate that the probability of high-flow events decrease, while 

the probability of extreme low-flow events also decrease (Figures 8-9). For example, there was a 

1-5% chance that a single or seven-day flow event would exceed 10,000 cfs prior to the 

construction of Buford Dam (Figure 8). However, after the construction of the dam, the 

probability that a similar event would occur dropped well below 1% (Figure 9). By contrast, 

extreme low-flow events occurred with lower frequency after the construction of the dam 

(Figures 8-9). Overall, there are sufficient data covering much of the historical flows 

downstream of Buford Dam for the past 100 years and no additional monitoring is needed within 

CHAT. 

Figure 2. Land cover and watershed map for Chattahoochee National Recreation Area (CHAT). 
19 

Table 5. Chattahoochee National Recreation Area (CHAT) landcover within the park, within a 5-km buffer, 

and its HUC 8 watershed. 

Within Park 5-km buffer HUC 8 Watershed 

 Acres Percent Acres Percent Acres Percent 

Open Water 1450.90 16.67 8391.62 4.10 42715.38 4.21 

Developed Open Space 668.30 7.68 52274.58 25.51 145173.79 14.29 

Developed Low Intensity 634.94 7.29 46667.56 22.78 96106.37 9.46 

Developed Medium Intensity 119.43 1.37 15000.98 7.32 34515.23 3.40 

Developed High Intensity 6.00 0.07 7047.03 3.44 19524.49 1.92 

Barren Land 48.04 0.55 2205.04 1.08 6937.38 0.68 

Deciduous Forest 4143.66 47.60 37453.52 18.28 400111.67 39.39 

Evergreen Forest 645.17 7.41 22650.91 11.06 97805.03 9.63 

Mixed Forest 97.41 1.12 1013.45 0.49 17601.88 1.73 

Shrub/Scrub 13.57 0.16 302.23 0.15 5182.24 0.51 

Grassland/Herbaceous 111.86 1.29 2347.60 1.15 31171.97 3.07 

Pasture/Hay 288.89 3.32 7276.76 3.55 112759.97 11.10 

Cultivated 0.00 0.00 19.79 0.01 71.39 0.01 

Woody Wetland 476.59 5.48 2227.95 1.09 6054.03 0.60 

Emergent Herbaceous Wetland 0.00 0.00 2.89 0.00 12.23 0.00 

Figure 3. USGS Gage 02335000. Average daily flow of the Chattahoochee River pre- and postconstruction of Buford Dam near Norcross, GA. 
20 

Figure 4. USGS Gage 02335000. Log Pearson III graph of high-flow return frequency for the 

Chattahoochee River near Norcross, GA, prior to the construction of Buford Dam. 

Figure 5. USGS Gage 02335000. Log Pearson III graph of high-flow return frequency for the 

Chattahoochee River near Norcross, GA, after the construction of Buford Dam. 
21 

Figure 6. USGS Gage 02335000. Log Pearson III graph of the seven-day low-flow return frequency for 

the Chattahoochee River near Norcross, GA, prior to the construction of Buford Dam. 

Figure 7. USGS Gage 02335000. Log Pearson III graph of the seven-day low-flow return frequency for 

the Chattahoochee River near Norcross, GA, after the construction of Buford Dam. 
22 

Figure 8. USGS Gage 02335000. Single day (dots) and seven-day (triangles) flow duration curves for 

single-day flow on the Chattahoochee River near Norcross, GA, prior to the construction of Buford Dam. 

Figure 9. USGS Gage 02335000. Single day (dots) and seven-day (triangles) flow duration curves for 

single-day flow on the Chattahoochee River near Norcross, GA, after to the construction of Buford Dam.
23 

CONG: Congaree National Park 

Within the Congaree National Park, less than 1% is classified as open water, but the majority of 

the land cover is dominated by forested (woody) wetlands (Figure 10; Table 5) which are 

inundated several times each year. Forested wetlands also surround much of the land cover 

within a 5-km buffer of CONG, but at the watershed level, deciduous forest and evergreen 

forests are the dominant land cover class (Table 5). 

Two rivers have a major influence on the surface water hydrology at CONG; the Congaree River 

(formed by the Broad and Saluda Rivers just upstream from CONG) and the Wateree River. 

Although not located directly in the park, USGS 02169500 (see Table 3) near Columbia, SC, has 

the longest flow data history and was therefore used to assess trends and extreme flow events for 

this river. While discharge data is unavailable within the park, the USGS maintains a gaging site 

(USGS 02169625) that only provides river stage. This is because streamflow exchanges with 

nearby CONG wetlands, precluding accurate discharge measurements. For the Wateree, gage 

02148315 (Table 3) below Eastover, SC, was examined. Extensive hydrologic modeling beyond 

the scope of this report has been conducted on CONG and should be used to supplement the 

analysis presented here (see Conrads et al. 2008; Doyle 2009; Merdun 1996; Merdun 2003) 

The Congaree River gage (2169500) is located 8,200 ft upstream of Granby Dam, which has 

little impact on the flow of the stream since water flows freely through an unused shipping lock 

adjacent to the dam. Two-thirds of the daily flow on the Congaree River is due to flow from 

Broad River and therefore is primarily responsible for the patterns observed in the average daily 

flow (Figure 11). Two gages do exist within the park (02169625 and 02169672), and 

relationships between gage height and streamflow within the Congaree River have been 

established previously (e.g. Patterson et al. 1985). 

Examination of high-flow return frequency indicates that events exceeding 100,000 cfs occur 

almost every 5 years and the Congaree did exceed 150,000 cfs in the late 1970s (Figure 12). Log 

Pearson III projections indicate that the 7-day low-flow will only dip below 1,000 cfs every 100 

years (Figure 13); however, the data indicate that it has happened at least twice since records 

have been kept. The flow duration curve indicates that the probability that the flow will exceed 

60,000 cfs is less than 1% and that there is a greater than 50% chance that the flow will be less 

than 10,000 cfs (Figure 14). 

The Wateree River has a similar pattern of flow that is also heavily influenced by an upstream 

dam at the base of Wateree Lake. This results in highly variable flows, but does not exceed 

10,000 cfs (Figure 15). The high-flow return frequency indicates that flow events greater than 

10,000 cfs do occur every four to five years, however they rarely go much higher (Figure 16). 

Seven-day low-flow events dipping below 1,000 cfs could occur as frequently as < 10 years, 

however no 7-day events much lower than 1,000 cfs are on record for this gage (Figure 17). The 

flow duration curve illustrates that there is a less than 30% probability that the flow will exceed 

8,000, indicating that the flow is highly controlled since it does not exceed 10,000 cfs (Figure 

18). 
24 

Figure 10. Land cover and watershed map (HUC 4) for Congaree National Park (CONG). 
25 

Table 6. Congaree National Park (CONG) landcover within the park, within a 5-km buffer, and its HUC 8 

watershed. 

Within Park 5-km buffer HUC 8 Watershed 

 Acres Percent Acres Percent Acres Percent 

Open Water 142.56 0.59 1892.14 1.61 24486.34 1.98 

Developed Open Space 40.03 0.17 3061.04 2.60 69362.06 5.60 

Developed Low Intensity 4.45 0.02 607.58 0.52 41935.22 3.38 

Developed Medium Intensity 2.22 0.01 47.15 0.04 14300.88 1.15 

Developed High Intensity 0.22 0.00 2.22 0.00 5253.86 0.42 

Barren Land 0.00 0.00 0.00 0.00 7723.55 0.62 

Deciduous Forest 133.44 0.55 10453.45 8.89 181725.28 14.66 

Evergreen Forest 1226.95 5.06 19062.80 16.21 340332.83 27.46 

Mixed Forest 137.88 0.57 1133.32 0.96 41905.42 3.38 

Shrub/Scrub 10.01 0.04 620.48 0.53 8499.04 0.69 

Grassland/Herbaceous 8.45 0.03 12299.32 10.46 180231.45 14.54 

Pasture/Hay 10.01 0.04 2592.23 2.20 55559.35 4.48 

Cultivated 8.45 0.03 7310.12 6.22 63310.25 5.11 

Woody Wetland 22488.12 92.81 57940.08 49.27 201583.58 16.26 

Emergent Herbaceous Wetland 30.25 0.12 576.67 0.49 3351.27 0.27 

Figure 11. USGS Gage 02169500. Average daily flow of the Congaree River at Columbia, SC. 
26 

Figure 12. USGS Gage 02169500. Log Pearson III graph of high-flow return frequency for the Congaree 

River at Columbia, SC. 

. 

Figure 13. USGS Gage 02169500. Log Pearson III graph of the seven-day low-flow return frequency for 

the Congaree River at Columbia, SC. 
27 

Figure 14. USGS Gage 02169500. Flow duration curves for seven-day (triangles) and single day (dots) 

flow duration for the Congaree River at Columbia, SC. 

Figure 15. USGS Gage 02148315. Average daily flow for the Wateree River below Eastover, SC. 
28 

Figure 16. USGS Gage 02148315. Log Pearson III graph of high-flow return frequency for the Wateree 

River below Eastover, SC. 

Figure 17. USGS Gage 02148315. Log Pearson III graph of seven-day low-flow return frequency for the 

Wateree River below Eastover, SC.
29 

Figure 18. USGS Gage 02148315. Flow duration curves for seven-day (triangles) and single day (dots) 

flow duration for the Wateree River at Columbia, SC. 

FOFR: Fort Frederica National Monument 

Despite its coastal location, less than 1% of the land is classified as open water within the 

monument. The majority of the land cover is considered emergent herbaceous wetland (Figure 

19; Table 6). Within a 5-km buffer surrounding FOFR, emergent herbaceous wetlands also 

dominate. At the watershed level, however, the majority of the landscape is evergreen forest, but 

wetlands are also widespread (Table 6). 

No gages are found within the boundaries of Fort Frederica, however three gages are located 

nearby, but only one contains data up to 2009 (0226180; Table 3). As of the time of writing this 

report, this data only runs through 6/17/2009. None of the gages contain discharge data, although 

this would be of little use in a coastal system that is mostly dominated by tidal action. Maximum 

gage height rarely exceeds 6 feet, although direct impact from a major storm would likely push 

the maximum much higher (Figure 20). Minimum gage heights reached nearly -8 feet in 2009 

and no mean was reported, but can easily be inferred from examination of the graph. If trends are 

to be assessed at this location, it will require a long-term data set to determine what types of 

impact tropical systems may impart to Fort Frederica, especially in conjunction with sea level 

rise (see Appendix C). 
30 

Figure 19. Land cover and watershed map for Fort Frederica National Monument (FOFR). 
31 

 Table 7. Fort Frederica National Monument (FOFR) land cover within the park, within a 5-km buffer, and 

its HUC 8 watershed. 

Within Park 5-km buffer HUC 8 Watershed 

 Acres Percent Acres Percent Acres Percent 

Open Water 1.78 0.63 5067.04 14.60 54548.56 10.95 

Developed Open Space 4.23 1.50 2461.02 7.09 26249.49 5.27 

Developed Low Intensity 0.00 0.00 1071.50 3.09 9715.10 1.95 

Developed Medium Intensity 0.00 0.00 275.99 0.80 2724.78 0.55 

Developed High Intensity 0.00 0.00 85.84 0.25 1440.45 0.29 

Barren Land 0.00 0.00 322.69 0.93 4568.88 0.92 

Deciduous Forest 0.00 0.00 81.84 0.24 7736.89 1.55 

Evergreen Forest 86.73 30.88 5135.32 14.80 143480.26 28.79 

Mixed Forest 2.67 0.95 758.81 2.19 13670.39 2.74 

Shrub/Scrub 9.56 3.40 23.13 0.07 3603.69 0.72 

Grassland/Herbaceous 0.00 0.00 323.14 0.93 37179.75 7.46 

Pasture/Hay 9.56 3.40 165.91 0.48 3719.11 0.75 

Cultivated 0.00 0.00 0.00 0.00 1501.83 0.30 

Woody Wetland 0.89 0.32 1260.53 3.63 79270.64 15.91 

Emergent Herbaceous Wetland 164.13 58.43 17665.49 50.91 108973.25 21.87 

Figure 20. USGS 0226180. Daily stream height located near Fort Frederica. 
32 

FOMA: Fort Matanzas National Monument 

Fifteen percent of the land is classified as open water within FOMA. The majority of the land 

cover is considered emergent herbaceous wetland, followed by evergreen forest (Figure 21; 

Table 7). Within a 5-km buffer surrounding FOMA, emergent herbaceous wetlands and 

evergreen forests also dominate. At the watershed level, however, the dominant wetland type 

shifts from herbaceous wetlands to woody wetlands (Table 7). 

The nearest gage with data that may be relevant to Fort Matanzas is located on the St. John’s 

River near Satsuma, FL, and not located within the park’s boundaries (Table 3). It contains 

current and historical data on discharge and gage height back to 1992 and 1990 respectively. 

However, this is a short period of time from which to assess flood potential. Additionally, there 

are many gaps in the data since that time (Figure 22). Additionally, only mean height is reported; 

therefore, there is no indication of what the maximum and minimum heights could be. Mean 

height ranged from a low of 8.5 ft in the early 1990s to a high of nearly 14 ft occurring at various 

times since record keeping began (Figure 22). Storm surge, combined with potential sea-level 

rise, could inundate the majority of FOMA (see Appendix C). Therefore, long-term monitoring, 

including maximum and minimum gage height, is recommended. 

Table 8. Fort Matanzas National Monument (FOMA) land cover within the park, within a 5-km buffer, and 

its HUC 8 watershed. 

Within Park 5-km buffer HUC 8 Watershed 

 Acres Percent Acres Percent Acres Percent 

Open Water 43.81 14.65 2168.57 13.77 25811.15 5.32 

Developed Open Space 3.78 1.26 296.01 1.88 54084.20 11.14 

Developed Low Intensity 13.57 4.54 421.66 2.68 51976.57 10.71 

Developed Medium Intensity 11.12 3.72 124.76 0.79 12857.09 2.65 

Developed High Intensity 2.45 0.82 16.68 0.11 3071.50 0.63 

Barren Land 43.81 14.65 837.32 5.32 7201.81 1.48 

Deciduous Forest 0.00 0.00 49.59 0.31 1840.76 0.38 

Evergreen Forest 59.38 19.85 3328.36 21.13 115504.32 23.80 

Mixed Forest 30.91 10.33 48.70 0.31 1840.76 0.38 

Shrub/Scrub 15.79 5.28 73.61 0.47 2876.90 0.59 

Grassland/Herbaceous 0.00 0.00 2420.10 15.36 55078.53 11.35 

Pasture/Hay 15.79 5.28 94.74 0.60 8998.76 1.85 

Cultivated 0.00 0.00 8.45 0.05 2387.19 0.49 

Woody Wetland 0.00 0.00 1996.44 12.67 95586.64 19.70 

Emergent Herbaceous Wetland 74.50 24.91 3867.00 24.55 46180.96 9.52 
33 

Figure 21. Land cover and watershed map for Fort Matanzas National Monument (FOMA). 
34 

Figure 22. USGS 02244040. Daily stream height located near Fort Matanzas (FOMA). 

FOPU: Fort Pulaski National Monument 

Open water and emergent herbaceous wetlands make up over 90% of the land cover types within 

FOPU (Figure 23; Table 8). Within a 5-km buffer surrounding FOMA, > 80% of the land cover 

is also comprised of open water and herbaceous wetlands. At the watershed level, however, the 

dominant wetland type begins to shift from herbaceous wetlands to woody wetlands and 

evergreen forests make up 25% of the landscape (Table 8). 

Until 2006, Fort Pulaski appears to have had adequate monitoring of gage height that included 

daily maximum, minimum, and mean height (Table 3; Figure 24). Nearby gages include USGS 

021989773 located on the Savannah River at US Army Corps of Engineers (USACE) dock at 

Savannah, GA, and USGS 02198840 on the Savannah River near Port Wentworth, GA. Both 

gages are presently reporting gage height at the USGS website; however, USGS 02198840 

summary tables indicate that historical gage height data is only available through 2005. 

For USGS gage 2198980, maximum gage height was recorded at approximately 10 ft on 

multiple occasions from 1993 - 2001, however an abnormality in the data appears in the mean 

height in the fall of 1993 and indicates a height over 25 feet. This does not appear to be 

associated with any tropical system, but it is unclear why this abnormality occurred. Maximum, 

minimum, and mean height appear to have all dropped three to four ft in late 2001, however this 

was not due to an actual change in height, but a change in the datum used for this gage. As of 

December 2005, gage height is no longer being recorded at this station. Since Fort Pulaski is 

located in a highly dynamic system susceptible to tropical systems, potential sea level rise (see 
35 

Appendix C), and changes caused due to dredging operations, it would be prudent to re-instate 

monitoring at this location. 

Table 9. Fort Pulaski National Monument (FOPU) land cover within the park, within a 5-km buffer and its 

HUC 8 watershed. 

Within Park 5-km buffer HUC 8 Watershed 

 Acres Percent Acres Percent Acres Percent 

Open Water 1430.22 25.82 23776.68 36.49 42220.55 2.90 

Developed Open Space 211.72 3.82 2322.02 3.56 67868.68 4.67 

Developed Low Intensity 73.17 1.32 1715.11 2.63 25996.62 1.79 

Developed Medium Intensity 0.00 0.00 513.51 0.79 9429.99 0.65 

Developed High Intensity 0.00 0.00 238.63 0.37 5873.89 0.40 

Barren Land 26.24 0.47 2144.55 3.29 6903.36 0.47 

Deciduous Forest 0.00 0.00 394.97 0.61 59891.82 4.12 

Evergreen Forest 100.30 1.81 2417.43 3.71 375262.39 25.80 

Mixed Forest 39.14 0.71 389.86 0.60 53772.63 3.70 

Shrub/Scrub 23.57 0.43 52.49 0.08 15063.25 1.04 

Grassland/Herbaceous 0.00 0.00 1444.01 2.22 129556.78 8.91 

Pasture/Hay 23.57 0.43 214.61 0.33 24885.76 1.71 

Cultivated 0.00 0.00 62.27 0.10 45500.43 3.13 

Woody Wetland 25.35 0.46 921.16 1.41 334220.09 22.97 

Emergent Herbaceous Wetland 3599.91 65.00 28560.39 43.83 258291.37 17.76 
36 

Figure 23. Land cover and watershed map for Fort Pulaski National Monument (FOPU). 
37 

Figure 24. USGS gage 02198980. Gage height on the Savannah River at Fort Pulaski, GA. Spike in the 

early 1990s appears to be an unexplained data anomaly, as is the downward shift in height in 2001. 

FOSU: Fort Sumter National Monument 

Fort Sumter National Monument is comprised mainly of developed land cover types that make 

up over 50% of the land area within the park (Figure 25; Table 9). Within a 5-km buffer 

surrounding FOSU, herbaceous wetlands dominate the landscape, followed by various intensities 

of development. At the watershed level, however, woody wetlands and evergreen forests are the 

primary land cover types and comprise over 50% of the area (Table 9). 

There are eight USGS gaging stations near Fort Sumter, but only four are currently active (Table 

3). USGS 02172100 was located on Fort Sumter and contains historical data for gage height 

from 1992 – 2005 (Figure 26). Nearby, USGS 021720711 (Figure 27) located on the Cooper 

River at Customs house at Charleston, SC, contains maximum and minimum gage height data 

beginning in August 1984 and is still currently active. However, much of the historical data from 

the Cooper River gage is still provisional. 

For USGS 02172100 located on Fort Sumter, maximum and minimum gage heights were 

reported between 14 – 16 ft and approximately 6 – 10 ft respectively. However, this record is 

very brief, running for a short time during the 1990s and again from late 2004 – 2005, with large 

gaps in the data between the two time periods. However, when you compare the gage height at 

Fort Sumter to nearby USGS 021720711 (Figure 27), it reports a minimum gage height that is 

nearly equivalent to the maximum gage height ever reported at Fort Sumter. This indicates that 

although there is monitoring being conducted nearby, the tidal behavior at each location appears 

to affect each site differently. Further monitoring is probably required to determine how each 
38 

gage reflects the water height at the other location. Once this is accomplished, it can be 

determined if long-term monitoring is necessary. Additionally, like other coastal parks within the 

SECN, vulnerability to storm surge and sea level rise (see Appendix C) warrants the collection of 

accurate, long-term data. 

Figure 25. Land cover and watershed map for Fort Sumter National Monument (FOSU). 
39 

Table 10. Fort Sumter National Monument (FOSU) land cover within the park, within a 5-km buffer, and 

its HUC 8 watershed. 

Within Park 5-km buffer HUC 8 Watershed 

 Acres Percent Acres Percent Acres Percent 

Open Water 2.00 2.63 4146.33 17.25 104413.71 13.02 

Developed Open Space 16.90 22.22 2543.53 10.58 47533.78 5.93 

Developed Low Intensity 21.13 27.78 3569.66 14.85 38415.15 4.79 

Developed Medium Intensity 1.78 2.34 1960.86 8.16 12826.40 1.60 

Developed High Intensity 0.00 0.00 826.64 3.44 5240.51 0.65 

Barren Land 2.45 3.22 362.06 1.51 1581.23 0.20 

Deciduous Forest 2.67 3.51 104.75 0.44 21957.04 2.74 

Evergreen Forest 6.67 8.77 877.79 3.65 205565.11 25.63 

Mixed Forest 18.24 23.98 42.92 0.18 16130.52 2.01 

Shrub/Scrub 0.00 0.00 279.77 1.16 28622.22 3.57 

Grassland/Herbaceous 0.89 1.17 977.87 4.07 37078.11 4.62 

Pasture/Hay 0.00 0.00 114.09 0.47 25448.20 3.17 

Cultivated 0.89 1.17 227.07 0.94 13270.75 1.65 

Woody Wetland 1.11 1.46 783.72 3.26 200190.05 24.96 

Emergent Herbaceous Wetland 0.00 0.00 7224.50 30.05 43863.38 5.47 

Figure 26. USGS 02172100 located at Fort Sumter near Mt. Pleasant, SC. 
40 

Figure 27. USGS 021720711 on the Cooper River at Customs House at Charleston, SC, near Fort 

Sumter. 

HOBE: Horseshoe Bend National Military Park 

Land cover within Horseshoe Bend is primarily deciduous and evergreen forest and comprises 

approximately 85% of the landscape (Figure 28; Table 10). Within a 5-km buffer surrounding 

the park and at the watershed level, these same land cover types dominate, however, within the 

buffer more open space is developed (Table 10). 

Two gages contain data relevant the surface water hydrology of Horseshoe bend (Table 3). 

USGS 02414715 is located at Horseshoe Bend and USGS 02414500 is located at Wadely, AL, 

on the Tallapoosa River. The gage located at Wadely, AL, contains historical data beginning in 

1923 and is still being monitored at the time of writing (Table 3). USGS 02414715 located at 

Horseshoe Bend contains historical data beginning in 1985 and therefore contains no data prior 

to the construction of the R.L. Harris Dam. 

The flow of the Tallapoosa River is primarily controlled from water released by the R.L. Harris 

Dam located below Lake Wedowee to the north and is controlled by the Alabama Power 

Company. Prior to the construction of the dam, the maximum discharge recorded at Wadely, AL, 

was approximately 67,000 cfs (Figure 29), but since its completion, a maximum discharge 
41 

exceeding 100,000 cfs was recorded only once in May, 2003 (Figure 30). The maximum 

discharge recorded at Horseshoe bend also exceeded 100,000 cfs that same month (Figure 31). 

Since the USGS Gage at Wadely, AL, contained the longer time series for discharge data, preand post- dam data were analyzed at this location instead of at Horseshoe Bend. The Log 

Pearson III estimation of the return frequency for high-flow projects that a discharge event 

exceeding 100,000 cfs should have only occurred less than one time every 1000 years prior to 

the construction of the dam (Figure 32). After the construction of the dam, the Log Pearson III 

estimation for high-flow return frequency projects that a discharge event exceeding 100,000 cfs 

should occur at a similar rate, however the data do not fit distribution nearly as well and highflow events such as those observed in 2003, may occur much more frequently than the model 

suggests (Figure 33), possibly as frequently as every 25 years. 

The Log Pearson III estimation for the return frequency for seven-day low-flow projects that low 

flows below 100 cfs occurred every 40 – 50 years prior to the construction of the dam (Figure 

34). However, after the construction of the R.L. Harris Dam, seven-day low flows falling below 

100 cfs are projected to occur every 25 years (Figure 35). However, data for the seven-day low 

flow prior to dam construction (Figure 34) do not fit the distribution as well as data after the 

construction of the dam (Figure 35). 

Monitoring efforts at Horseshoe Bend are adequate and there appears to be a large degree of 

similarity between events observed upstream of Horseshoe Bend at Wadely, AL. However, there 

are some discrepancies that are worth noting. For example, high-flow events occurring between 

1987 and 1991 reached a maximum discharge of 60,000 cfs at Wadely, AL, but approached 

80,000 cfs at Horseshoe Bend. This pattern is seen for other high-flow events along the 

Tallapoosa and underscores the importance of maintaining a long-term gage at Horseshoe Bend 

since the amount of the land area drained at HOBE is substantially higher than upstream near 

Wadely, AL. 

Flow duration curves indicate that prior to dam construction there was a less than 1% probability 

that the average daily flow would exceed 40,000 cfs and that there was a greater than 50% 

probability that the average daily flow would be less than 5,000 cfs (Figure 36). After the 

construction of the dam there was a less than 1% probability that the average daily flow would 

exceed 20,000 cfs and a greater than 50% probability that the average daily flow would be less 

than 5,000 cfs (Figure 37). As mentioned earlier however, the high-flow event observed in 2003 

may indicate that these types of events occur at higher probabilities than indicated since the data 

fall outside of the distribution (Figure 38). 

 
42 

Figure 28. Land cover and watershed map for Horseshoe Bend National Military Park (HOBE). 

Table 11. Horseshoe Bend National Military Park (HOBE) land cover within the park, within a 5-km buffer, 

and its HUC 8 watershed. 

Within Park 5-km buffer HUC 8 Watershed 

Land Use/Land Cover Acres Percent Acres Percent Acres Percent 

Open Water 134.77 6.59 675.19 2.10 60469.38 3.15 

Developed Open Space 82.95 4.06 1148.67 3.57 87220.59 4.54 

Developed Low Intensity 0.00 0.00 40.92 0.13 22266.62 1.16 

Developed Medium Intensity 0.00 0.00 6.23 0.02 4532.18 0.24 

Developed High Intensity 0.00 0.00 0.00 0.00 1612.81 0.08 

Barren Land 0.00 0.00 432.34 1.34 20020.87 1.04 

Deciduous Forest 1072.17 52.41 13269.41 41.27 707828.97 36.87 

Evergreen Forest 657.84 32.16 10157.44 31.59 504559.64 26.28 

Mixed Forest 14.46 0.71 161.68 0.50 13041.90 0.68 

Shrub/Scrub 0.00 0.00 349.83 1.09 43206.87 2.25 

Grassland/Herbaceous 16.90 0.83 3033.02 9.43 152030.00 7.92 

Pasture/Hay 31.80 1.55 2259.98 7.03 272338.50 14.19 

Cultivated 0.00 0.00 0.00 0.00 413.21 0.02 

Woody Wetland 34.69 1.70 620.26 1.93 30330.65 1.58 

Emergent Herbaceous Wetland 0.00 0.00 0.00 0.00 8.23 0.00 

 
43 

Figure 29. USGS 02414500. Average daily flow for the Tallapoosa River at Wadely, AL. 

Figure 30. USGS 02414500. Average daily flow for the Tallapoosa River at Wadely, AL, after the 

construction of the R.L. Harris Dam. 
44 

Figure 31. USGS 2414715. Average daily flow for the Tallapoosa River near New Site, AL, (Horseshoe 

Bend). 

Figure 32. USGS 02414500. Log Pearson III graph of the high-flow return frequency for the Tallapoosa 

River at Wadely, AL, prior to the construction of R.L. Harris Dam. 
45 

Figure 33. USGS 02414500. Log Pearson III graph of the high-flow return frequency for the Tallapoosa 

River at Wadely, AL, after the construction of R.L. Harris Dam. 

Figure 34. USGS 02414500. Log Pearson III graph of the seven-day low-flow return frequency for the 

Tallapoosa River at Wadely, AL, prior to the construction of R.L. Harris Dam. 
46 

Figure 35. USGS 02414500. Log Pearson III graph of the seven-day low-flow return frequency for the 

Tallapoosa River at Wadely, AL, after the construction of R.L. Harris Dam. 

Figure 36. USGS 02414500. Flow duration curves for seven-day (triangles) and single day (dots) flow 

duration for the Tallapoosa River at Wadely, AL, prior to the construction of R.L. Harris Dam. 
47 

 

Figure 37. USGS 02414500. Flow duration curves for seven-day (triangles) and single day (dots) flow 

duration for the Tallapoosa River at Wadely, AL, after the construction of R.L. Harris dam. In 2003, a 

large flood event increased the single day average to approximately 85,000 cfs, the highest on record. 

KEMO: Kennesaw Mountain National Battlefield Park 

Land cover within Kennesaw Mountain NBP is primarily deciduous and evergreen forest and 

less than 1% is classified as open water (Figure 38; Table 11). Within a 5-km buffer surrounding 

the park, over 60% of the area is developed. At the watershed level, deciduous and evergreen 

forests dominate, although in slightly smaller proportions to those within the park (Table 11). 

The nearest USGS gage with discharge data (02336968) relevant to KEMO is located in Powder 

Springs, GA, on Noses Creek and contains current and historical data going back to 1998. An 

additional gage, USGS 02393377, is located on Butler Creek at Mack Dobbs near Kennesaw, 

GA, however it only contains data relevant to gage height and began recording data in 2007. 

Therefore, to project high-flow frequency and low-flow frequency, the Powder Springs gage data 

were analyzed. 

The maximum flow recorded on Noses Creek at Powder Springs occurred in 2004 and exceeded 

2,800 cfs (Figure 39). Examing the Log Pearson III projections based on the short term data and 

adjusted using the regional skew coefficient, a flow of this magnitude should occur, on average 

every 100 years (Figure 40). That is, there is a 1% chance that this type of event will happen in 

any given year. However, the amount of data available is limited, so this estimate should be 

interpreted with caution. Gage height data indicated that the flow observed on Noses Creek in 

2004 corresponded to a gage height of nearly 16 ft. Minor flood stage level for Noses Creek is 11 

ft. 
48 

The lowest flow recorded on Noses Creek was < 1 cfs and has occurred multiple times since 

record keeping began. Log Pearson III projections indicate that this type of event could occur 

every 4–5 years and is a common event in this stream (Figure 41). 

The flow duration curves for single and seven-day average flows indicate that the probability of 

average daily and seven-day flows will exceeding 800 cfs is less than 1% (Figure 42) and there is 

only a 5% chance that it will exceed 200 cfs. However, since multiple creeks, other than just 

Noses Creek, flow through KEMO more monitoring is advised since the surrounding 

metropolitan landcover likely increases the flash flooding potential especially as the level of 

development increases and encroaches on the park. 

Table 12. Kennesaw Mountain National Battlefield Park (KEMO) land cover within the park, within a 5-km 

buffer, and its HUC 8 watershed. 

Within Park 5-km buffer HUC 8 Watershed 

 Acres Percent Acres Percent Acres Percent 

Open Water 1.56 0.05 379.63 0.87 77282.21 2.44 

Developed Open Space 198.82 6.84 10329.57 23.73 263516.09 8.32 

Developed Low Intensity 15.35 0.53 10159.22 23.34 134372.97 4.24 

Developed Medium Intensity 0.89 0.03 3188.92 7.33 29727.74 0.94 

Developed High Intensity 0.22 0.01 1916.38 4.40 14614.23 0.46 

Barren Land 0.89 0.03 404.54 0.93 22762.78 0.72 

Deciduous Forest 1388.63 47.77 6696.31 15.38 1116497.28 35.26 

Evergreen Forest 1072.83 36.91 6979.19 16.03 737785.55 23.30 

Mixed Forest 25.80 0.89 235.96 0.54 69057.38 2.18 

Shrub/Scrub 161.46 5.55 59.16 0.14 58009.03 1.83 

Grassland/Herbaceous 0.00 0.00 512.40 1.18 168338.00 5.32 

Pasture/Hay 161.46 5.55 2045.37 4.70 386901.87 12.22 

Cultivated 0.00 0.00 0.00 0.00 16159.21 0.51 

Woody Wetland 23.13 0.80 619.81 1.42 71755.25 2.27 

Emergent Herbaceous Wetland 0.00 0.00 0.00 0.00 38.70 0.00 
49 

Figure 38. Land cover and watershed map for Kennesaw Mountain National Battlefield Park (KEMO). 
50 

Figure 39. USGS 02336968 on Noses Creek at Powder Springs Road in Powder Springs, GA, south of 

Kennesaw Mountain National Battlefield Park. 

Figure 40. USGS 02336968. Log Pearson III for high-flow events on Noses Creek at Powder Springs 

Road in Powder Springs, GA, south of Kennesaw Mountain National Battlefield Park. 
51 

Figure 41. USGS 02336968. Log Pearson III for low-flow events on Noses Creek at Powder Springs 

Road in Powder Springs, GA, south of Kennesaw Mountain National Battlefield Park. 

Figure 42. USGS 02336968. Flow duration curves for 7-day (triangles) and single day (dots) flow 

duration for Noses Creek at Powder Springs Road in Powder Springs, GA, south of Kennesaw Mountain 

National Battlefield Park. 
52 

MOCR: Moores Creek National Battlefield 

Within Moores Creek National Battlefield, woody wetlands are the dominant land cover class 

and makes up 28% of the land area. However, the majority of landscape is made up of the two 

land cover classes of deciduous and evergreen forest (Figure 43; Table 12). Within a 5-km buffer 

surrounding MOCR, woody wetlands and evergreen forests dominate. At the watershed level, 

however, over 28% of the landscape is cultivated, with the remaining majority comprised 

primarily of woody wetlands and evergreen forest (Table 12). 

No USGS gages are located within Moores Creek National Battlefield. However, 3 gages are 

located on nearby rivers including USGS 02105769 on the Cape Fear River at Lock #1 near 

Kelly, NC; USGS 0217544 on the Black River near Currie, NC; and USGS 02108566 on the 

Northeast Cape Fear River near Burgaw, NC. However, it is unlikely that these gages accurately 

reflect the behavior of Moores Creek. 

The only flow data available are from Mallin and McIver (2007) and were collected between 

3/21/96 and 6/14/96 (see literature review). The following is information summarized from this 

report. The maximum surface water elevation ranges from 12 ft above mean sea level for a twoyear frequency storm, to 32 ft for a 100-year storm (USACOE 2000). Maximum stream 

discharge ranges from 1,150 cfs for a two-year storm up to 5,940 cfs for the 100-year storm 

(USACOE 2000). Several tropical systems have affected Moores Creek including flooding from 

Hurricanes Fran (1996), Bonnie (1998), and Floyd (1999). 

Because the creek (Moores Creek) within MOCR is prone to frequent flooding and no long-term 

data are available, it is recommended that a long-term monitoring system be employed. 
53 

Figure 43. Land cover and watershed map for Moores Creek National Battlefield (MOCR). 
54 

Table 13. Moores Creek National Battlefield (MOCR) land cover within the park, within a 5-km buffer, and 

its HUC 8 watershed. 

Within Park 5-km buffer HUC 8 Watershed 

 Acres Percent Acres Percent Acres Percent 

Open Water 0.00 0.00 182.14 0.80 5421.99 0.54 

Developed Open Space 13.57 13.65 684.75 3.01 41186.19 4.09 

Developed Low Intensity 2.00 2.01 101.63 0.45 11713.76 1.16 

Developed Medium Intensity 0.00 0.00 0.67 0.00 2101.63 0.21 

Developed High Intensity 0.00 0.00 0.89 0.00 472.14 0.05 

Barren Land 0.00 0.00 0.00 0.00 448.35 0.04 

Deciduous Forest 6.00 6.04 280.00 1.23 30191.43 3.00 

Evergreen Forest 23.57 23.71 7084.39 31.13 185947.00 18.45 

Mixed Forest 20.24 20.36 644.06 2.83 47928.09 4.76 

Shrub/Scrub 0.00 0.00 1558.10 6.85 53969.22 5.35 

Grassland/Herbaceous 0.89 0.89 2792.83 12.27 108765.76 10.79 

Pasture/Hay 0.00 0.00 73.61 0.32 13849.86 1.37 

Cultivated 0.89 0.89 2082.51 9.15 290619.80 28.83 

Woody Wetland 27.80 27.96 7025.23 30.87 208074.62 20.64 

Emergent Herbaceous Wetland 0.00 0.00 248.86 1.09 7260.52 0.72 

OCMU: Ocmulgee National Monument 

Within the Ocmulgee National Monument, woody wetlands and deciduous forests make up 

nearly 50% of all land cover classes (Figure 44; Table 13). Within the 5-km buffer surrounding 

OCMU, over 35% of the area is classified as developed, 15% is woody wetlands, and 25% is 

forested. At the HUC 8 watershed level, 20% is developed and approximately 50% is forested 

(Table 13). 

No USGS gages have been located within Ocmulgee National Monument. The nearest gage 

station with relevant data for the Ocmulgee River is located at Macon, GA (USGS 02213000). It 

contains historical data from 1893 – present (Table 3). Other nearby gages include USGS 

02213050 located on Walnut Creek, near Gray, GA, which runs through OCMU and , and has 

historical data from 1961 – 1994. Additionally, USGS 02210500 on the Ocmulgee River near 

Jackson, GA, contains historical data from 1906 – present. However, this gage is located much 

farther upstream than the Macon, GA, gage so only data from the Macon, GA, gage were 

analyzed. 

The nearest hydroelectric dam upstream on the Ocmulgee River is located on Jackson Lake and 

was created in 1910. An additional reservoir, Lake Juliette (on Rum Creek), is located between 

Jackson Lake and OCMU, but is only used for cooling Scherer’s coal power plant. Although 

water is pumped directly from the Ocmulgee River to augment lake levels it has little effect on 

the net flow the Ocmulgee River. Therefore, to predict high and low-flow events we analyzed the 

data as a single time series although there is a substantial gap in the earlier portions of the data’s 

history (Figure 45). 

The maximum average daily flow on the Ocmulgee River at Macon, GA, reached 97,000 cfs in 

the 1994. Based on Log Pearson III predictions for high-flow events, it is predicted that this flow 

would occur less than once every 500 years (Figure 46). That is, for any given year there is less 
55 

than 0.05% chance that a high-flow event such as the one that occurred in 1994 will happen. The 

7-day Log Pearson III prediction for minimum flow indicate that discharge less than 500 cfs will 

occur at least once every 10 years (Figure 47). Single day flows well below 200 cfs have been 

recorded as recently as 1988. 

The flow duration curves for single and seven-day average flows indicate that there is a less than 

1% probability that the flow will exceed 25,000 cfs (Figure 48). It also predicts a greater than 

50% chance that both the daily and seven-day average flows will be less than 5,000 cfs (Figure 

48). 

Assuming that the gage located in Macon, GA, continues to operate, no further monitoring of the 

Ocmulgee River at OCMU is necessary. However, given that there are several creeks present in 

the park, the installation of staff gages that are monitored by park employees is recommended 

(see Appendix B). 

Table 14. Ocmulgee National Monument (OCMU) land cover within the park, within a 5-km buffer, and its 

HUC 8 watershed. 

Within Park 5-km buffer HUC 8 Watershed 

 Acres Percent Acres Percent Acres Percent 

Open Water 2.22 0.32 826.86 2.37 32191.43 1.69 

Developed Open Space 38.47 5.52 5370.61 15.40 192502.09 10.11 

Developed Low Intensity 37.81 5.42 4367.17 12.53 129924.85 6.82 

Developed Medium Intensity 7.56 1.08 2620.70 7.52 36869.28 1.94 

Developed High Intensity 0.00 0.00 1105.75 3.17 19991.96 1.05 

Barren Land 0.00 0.00 307.35 0.88 20078.92 1.05 

Deciduous Forest 120.98 17.35 6412.98 18.39 488905.04 25.67 

Evergreen Forest 43.37 6.22 2438.78 7.00 417144.90 21.90 

Mixed Forest 32.91 4.72 1990.21 5.71 69815.75 3.67 

Shrub/Scrub 37.14 5.33 131.88 0.38 19146.86 1.01 

Grassland/Herbaceous 3.78 0.54 2202.82 6.32 130792.19 6.87 

Pasture/Hay 37.14 5.33 717.00 2.06 250007.39 13.13 

Cultivated 3.78 0.54 243.30 0.70 9036.35 0.47 

Woody Wetland 219.95 31.55 5329.69 15.29 85894.89 4.51 

Emergent Herbaceous Wetland 43.14 6.19 797.73 2.29 2501.27 0.13 
56 

Figure 44. Land cover and watershed map of Ocmulgee National Monument (OCMU). 
57 

Figure 45. Average daily flow for USGS 02213000 located on the Ocmulgee River at Macon, GA, south 

of Ocmulgee National Monument. 

Figure 46. Log Pearson III graph of high-flow return frequency for USGS 02213000 located on the 

Ocmulgee River at Macon, GA, south of Ocmulgee National Monument. 
58 

Figure 47. Log Pearson III graph of low-flow return frequency for USGS 02213000 located on the 

Ocmulgee River at Macon, GA, south of Ocmulgee National Monument. 

Figure 48. Flow duration curves for seven-day (triangles) and single-day (dots) flow duration for USGS 

02213000 located on the Ocmulgee River at Macon, GA, south of Ocmulgee National Monument. 
59 

TIMU: Timucuan Ecological and Historic Preserve 

Land cover within Timucuan Ecological and Historic Preserve is over 50% emergent herbaceous 

wetland and 22% open water (Figure 49; Table 14). Within a- 5-km buffer surrounding TIMU, 

wetlands and evergreen forest dominate, but only 14% is open water. At the watershed level, 

wetlands and evergreen forest are found at slightly higher proportions and only 7% of the 

landscape at the watershed scale is classified as open water (Table 14). 

Two USGS gages are relevant to TIMU; USGS 02231289 on the Nassau River just outside the 

park boundary and USGS 02246500 on the St. Johns River at Jacksonville, FL. However, data 

collection on the Nassau River gage in the park ceased in 2004 (Table 3, Figure 50). Data 

collection on the St. Johns River is current and contains historical data back to 1971 (Figure 51). 

Daily mean, minimum, and maximum height data are available for both gages. 

The maximum gage height observed at TIMU recorded at gage 02231289 rarely exceeds 15 ft 

(Figure 50). Historical gage heights observed between the formerly active gage located within 

the boundary of TIMU, and the currently active gage on the St. Johns River, are similar in 

maximum and minimum heights observed (although heights at TIMU appear to be slightly 

higher). Since the St. Johns River gage closely mirrors what was actually measured within the 

boundary of TIMU, it is probably not necessary to incorporate additional monitoring. However, 

in the event that the St. Johns River gage is discontinued and considering the preserve’s 

vulnerability to storm surge and sea level rise (see Appendix C), re-instating the gage at TIMU is 

recommended. 

Table 15. Timucuan Ecological and Historic Preserve (TIMU) land cover within the park, within a 5-km 

buffer, and its HUC 8 watershed. 

Within Park 5-km buffer HUC 8 Watershed 

 Acres Percent Acres Percent Acres Percent 

Open Water 10160.11 22.25 23852.29 13.82 147938.38 7.20 

Developed Open Space 635.60 1.39 13202.69 7.65 204020.14 9.93 

Developed Low Intensity 779.27 1.71 9931.71 5.75 103904.43 5.06 

Developed Medium Intensity 218.84 0.48 3067.27 1.78 31595.19 1.54 

Developed High Intensity 180.81 0.40 2174.35 1.26 14430.76 0.70 

Barren Land 452.57 0.99 2240.85 1.30 9456.67 0.46 

Deciduous Forest 24.24 0.05 678.53 0.39 18437.20 0.90 

Evergreen Forest 5130.43 11.24 38271.26 22.17 595030.75 28.96 

Mixed Forest 721.00 1.58 3284.77 1.90 37643.89 1.83 

Shrub/Scrub 14.23 0.03 468.81 0.27 26100.70 1.27 

Grassland/Herbaceous 0.22 0.00 9632.59 5.58 249804.79 12.16 

Pasture/Hay 14.23 0.03 1540.97 0.89 68719.78 3.34 

Cultivated 0.22 0.00 208.61 0.12 44904.19 2.19 

Woody Wetland 2531.30 5.54 21506.69 12.46 429835.41 20.92 

Emergent Herbaceous Wetland 24442.53 53.53 42588.61 24.67 73066.71 3.56 
60 

Figure 49. Land cover and watershed map for Timucuan Ecological and Historic Preserve (TIMU). 
61 

Figure 50. USGS 02231289 on the Nassau River near Hedges, FL, and within the boundary of Timucuan 

Ecological and Historic Preserve. 

Figure 51. USGS 02246500 on the St. Johns River at Jacksonville, FL, near Timucuan Ecological and 

Historic Preserve.
62 
63 

Summary of Water Quantity Monitoring at SECN Parks 

All flow data analyzed for this report is maintained by the USGS and is easily accessed via the 

Internet. Program River2 and UpdateSW can be used to analyze historical flows to develop 

models of flow regimes. 

For CHAT, five currently active gaging stations with flow data are available with pre- and postdam construction. Construction of Buford Dam decreased the frequency, duration, and 

magnitude of peak events and increased the magnitude of seven-day low flows. Sufficient 

monitoring is currently in place. 

Both the Congaree and Wateree Rivers influence CONG, and each are influenced by upstream 

dams. Previous examinations have related gage heights within the park to streamflow on the 

Congaree River. Additional monitoring is likely needed within the park to predict future effects 

of development and dam re-licensing. 

No gages are located within FOFR, but three are located nearby. However, only one gage 

contains data up to 2009 (but no reporting since 6/17/2009 as of this report). 

No gages are located within FOMA boundaries, but one is located at Satsuma, FL, on the St. 

Johns River. However, this data only goes back to early 1990s and many gaps in the data are 

present. Additionally, only mean height is reported which may be of little use in predicting the 

height of storm surges. 

Adequate monitoring was available until 2006 on FOPU. Nearby gages were active until as 

recently as March 2009, but data collection appears to have been discontinued. Further 

monitoring is likely needed. 

Four gages near FOSU are currently active; there are no active gages within the FOSU (ceased in 

2005). Differences in nearby gages and historical gage heights collected on Fort Sumter indicate 

that tidal behavior may differ on Fort Sumter and the nearest currently active gage on the Cooper 

River. 

There are two currently active gages providing relevant flow data for HOBE, one located 

upstream at Wadely, AL, and one located on HOBE itself. High-flow events occurred in 2003 

and were higher than those projected by Log Pearson III models. This may indicate that either 

the data poorly fit the model or this was an extremely rare event. 

No gages are located within KEMO, however there is a gage located on Noses Creek at Powder 

Springs, but only contains data going back to 1998. Multiple creeks, other than Noses Creek, 

influence the surface water hydrology at KEMO so further monitoring may be necessary given 

that increases in development around the park may increase the flash flood potential in this area. 

No USGS gages are located within MOCR and frequent flooding has been observed. Only a 

single study has been conducted which collected surface water elevation and discharge, but the 

data were collected over a short period of time (< four months). Further monitoring is likely 

necessary. 
64 

No gages are found on OCMU, however long-term data is available at Macon, GA, on the 

Ocmulgee River. Adequate data is available for analysis, however OCMU is also influenced by 

other creeks that run through the park, so further monitoring may be necessary. 

Gage height monitoring ceased within TIMU in 2004, however data for the nearby St. Johns 

River is available. Comparison of gage heights observed at TIMU and at the St. Johns River 

gage, indicate a large degree of similarity, so further monitoring may not be needed unless the St. 

Johns River gage is discontinued.
65 

Surface Water Concerns and Suggested Methods for 

Analysis 

This section provides a brief overview of possible concerns related to SECN parks. Table 15 

provides a summary of likely stresses to the surface hydrologic system at these parks. Note that 

the list of concerns was based on the proximity to coastal waters, as well as the proximity of 

potential stresses. Three tools are presented that were used for the analysis of surface water 

disturbances, as well as for the management of surface water data. UpdateSW and River2 are 

programs created by Dr. John Dowd at the University of Georgia to automatically retrieve 

current and historical data from USGS databases and run similar analyses to those presented in 

this report as well as others. Detailed instructions and examples for how to use these programs 

are provided in Appendix A. 

Indicators of Hydrologic Alteration (IHA) is a program developed by the Nature Conservancy 

(TNC) in conjunction with Totten Software Design and Smythe Scientific Software to quantify 

the characteristics of natural and altered hydrologic systems (TNC 2007). Mathews and Richter 

(2007) suggest using IHA in conjunction with other statistics, such as those generated by River2, 

and organism specific statistics when making environmental flow recommendations. 

The primary purpose of presenting these tools within this document is to provide park 

employees, researchers, and managers with simple-to-use tools that will enable comparisons of 

hydrologic characteristics for different scenarios other than those presented in this report. This is 

important since it is most often the case that different NPS lands have varying interests in surface 

water hydrology for different reasons. Additionally, urban development, changes in landcover, 

salt water intrusion, local climate changes, and projected rises in sea level will all impact each 

park in a different manner. 

Table 16. Potential surface water management concerns at SECN parks.

Dams Point 

Source 

Non-Point 

Source Drought Erosion Dredging Tidal Influence Hurricanes Withdrawals 

CONG X X X X X X X 

CHAT X X X X X X 

FOMA X X X X 

FOFR X X X X 

FOPU X X X X X 

FOSU X X X X X 

HOBE X X X X X 

KEMO X X X 

MOCR X X X X 

OCMU X X X X X X 

TIMU X X X X X X X 
66 

Indicators of Hydrologic Alteration software, was developed in order allow hydrologic processes 

to be rapidly assessed. The advantage of this software is its ability to utilize any form of 

hydrologic data including streamflows, river stages, ground water levels, and lake levels. The 

disadvantage is the long-term data sets typically required to run useful analysis. This, however, is 

also an advantage of the program since examining long-term data in a meaningful way is often a 

daunting task. As a general rule, 20 years of daily data are recommended for estimating many of 

the parameters for analysis (TNC 2007), but this requirement varies depending on the goal of the 

analysis and variability within the system being characterized. 

IHA calculates a total of 67 statistical parameters divided into two groups: Environmental Flow 

Component (EFC) parameters and the Indicators of Hydrologic Alteration (IHA) (Table 16). 

Many of these parameters are correlated with each other (Olden and Poff 2003), so caution 

should be exercised when examining the output and the parameters should typically be chosen a 

priori. A brief example analysis of the Chattahoochee River below Buford Dam is provided 

below. 

One of the most useful tools in program IHA is the Range of Variability analysis (Richter et al. 

1997). The purpose of RVA analysis is to compare flows from one time period to another and 

determine the range of variability that was present prior to the “disturbance” of the natural 

regime. The goal of the analysis is to quickly identify what the range of variability is in order to 

set goals for management that may have an impact on flow. Once these have been identified, 

then biological and/or water quality changes can be monitored. If, for example, it is determined 

that any decrease below 30% of the natural range of variability of the original streamflow results 

in lethally low water levels resulting in mass die-offs of native mussels, then adaptive 

management recommendations can be made. Richter et al. (1997) provides a 6-step adaptive 

approach for setting management goals and provides additional examples of RVA analysis. 

Additionally, Mathews and Richter (2007) provide a detailed description of prescribing flows 

within an adaptive framework. 

For this example, the time period prior to the creation of Buford Dam on the Chattahoochee is 

compared to post-dam flows. This analysis is for illustrative purposes only and is only meant to 

show some of the capabilities of the IHA program and is not intended as a management 

recommendation. The RVA analysis indicates that for October monthly flows prior the 

construction of Buford Dam yielded a Low Hydrologic Alteration Factor (HA) of -0.8814, a 

Middle HA of -0.6368 and a High HA of 1.609 (Figure 52). HA is calculated as: 

 HA = (OF – EF ) / EF 

Where OF is the observed frequency and EF is the expected frequency. The statistic is estimated 

for three categories: Low HA (0-33rd percentile), Middle HA (34th – 67th percentile) and High 

HA (>67th percentile). Therefore, a negative Low HA indicates that the frequency of values 

falling within the 33rd percentile for the range of variability has decreased substantially. While a 

positive High HA indicates that the frequency of values > 67th percentile has increased. 
67 

Table 17. List of Indicators of Hydrologic Alteration and Environmental Flow Parameters from The Nature 

Conservancy’s IHA software manual (2007). 
68 

Table 16. (Continued) 
69 

Table 16. (Continued) 
70 

Table 16. (Continued) 
71 

Table 16. (Continued) 

The RVA analysis allows the user to specify what percentiles each category can be set. By 

default, it will divide the three categories as they are presented here, but this is arbitrary. 

Examining the graph of the pre-impact flows (Figure 52), it is evident that there was quite a bit 

of variation prior to the construction of the dam, therefore the RVA boundaries could be widened 

to capture more of the variation if desired. Additionally, when balancing human demands 

(hydropower and recreation) with environmental issues, fine tuning is often required. 

The RVA analysis only considers the 33 parameters that are related to IHA not the EFC 

parameters, so separate analyses are required if the EFC parameters are of interest. There are 

numerous components that can be examined (see Table 16), but for this example extreme low 

flows will be examined. 

To begin, a hydrograph delineating extreme low flows, low flows, high-flow pulses, small floods 

and large floods was graphed pre- and post-dam construction (Figure 53). It is obvious from the 

graph (and would be obvious from a standard hydrograph as well) that the creation of Buford 

Dam dampened the erratic flow of the Chattahoochee and virtually eliminated all large flood 

events. Program IHA allows you pick from any of the EFC parameters and examine them 

individually to determine to what degree each has been altered. 

To examine the frequency of extreme low flows, the frequency of occurrence was graphed 

(Figure 54). It appears from the graph that the creation of Buford Dam substantially increased the 

number of extreme low-flow events in the Chattahoochee River. However, it is important to 
72 

consider how the program defines extreme low flow. Program IHA defines the extreme low-flow 

threshold at the 10th percentile of all low flows. In order to make sure the program is 

appropriately defining low flows for the stream of interest, the EFC algorithm should be 

calibrated properly and details for doing this can be found in the IHA manual (TNC 2007). 

In addition to graphing the parameters of interest for both the IHA parameters and the EFC 

parameters, program IHA also creates of series of tables that include: an annual summaries table, 

a scorecard table, RVA table, box-and-whisker table (for creating box-and-whisker plots), 

regression table, percentile table, EFC table, and a message report. A detailed description for 

interpretation of the values can be found in the IHA manual (TNC 2007), but a few are 

highlighted below. 

The scorecard table contains a collection of statistics for pre- and post-impact time periods for 

each parameter examined. Some of these include mean annual flow, mean annual flow/ 

watershed area, annual coefficient of variation, flow predictability, flow constancy, maximum 

proportion of floods occurring during any common 60 day period, and length of flood free period 

in addition to also displaying the values used for calculating the EFC parameters. 

The RVA table displays the results that were used for the RVA analysis and displays information 

for each parameter examined. These include: mean or median coefficient of dispersion for preand post-impact parameters, minimum and maximum of each pre- and post- impact parameter, 

RVA boundaries (set by user or default), and the HA factor for the middle HA category, and then 

provides a second section that compares the distributions of data found within each category. 

It isn’t always the case that two well-defined time periods are necessary for analysis and this is 

not a prerequisite to calculating many of the parameters in the IHA program. In some instances, 

it may be of interest to simply characterize the flow for reports or biological assessments. It 

would also be possible to characterize and examine multiple, but similar streams to compare 

differences in ecosystem function that may be driven by differences in flow characteristics. 

Dams are the classic example of flow alteration; however analyses can be applied in more subtle 

ways. For example, it could be applied to flows in an area before and after development of a 

nearby shopping center on the flow of smaller streams (like those associated with CHAT or 

OCMU). It could also be used to examine the changes in flow due to increases in the percentages 

of urban areas near larger streams or changes in gage heights within CONG. Simulated data can 

also be incorporated to test future water management scenarios (Mathews and Richter 2007). For 

locations with limited amounts of data, this is probably the most useful way to employ the use of 

the IHA program. 

This is just a brief examination of some of the functions of program IHA. For a complete 

explanation and more details on how the program can be used and has been used in the past 

consult the IHA manual (TNC 2007) as well as the many of the publications mentioned above 

(e.g. Mathews and Richter 2007, Richter et al. 2003, Richter et al. 1997). 
73 

Figure 52. Range of Variability analysis for the Chattahoochee River near Norcross, GA. 

Figure 53. Graph of the frequency of extreme low flows, low flows, high-flow pulses, small floods, and 

large floods near Norcross, GA, before and after the construction of Buford Dam. 
74 

Figure 54. Graph of the frequency of extreme low-flow events on the Chattahoochee River near 

Norcross, GA, before and after the construction of Buford Dam. 
75 

Recommendations 

Table 17 summarizes monitoring recommendations for each park based on the above 

assessments. For most parks in the SECN, some form of water-quantity monitoring is available. 

The recommendations assume that the NPS desires to understand how flows may impact the 

integrity of their park and the safety of their visitors. Alternatively, if more detailed information 

is desired such that the park requires an understanding of how flow may impact the biological 

systems within the park, then tools are available (IHA, RIVER2) to examine flow data in this 

manner and a brief description and example analysis has been provided. In general, however, to 

understand the impact of surface water availability and flow on biological systems, long-term 

data sets are needed to document both hydrologic requirements of the biotic components of 

interest. Therefore, if there is any chance that the NPS may need this type of data at some point 

in the future, now is the time to begin monitoring. 

Parks impacted by anthropogenic disturbances (dams, withdraws, etc.): 

 Congaree National Park 

 Chattahoochee River National Recreational Area 

 Horseshoe Bend National Military Park 

 Timucuan Ecological & Historic Preserve 

 Ocmulgee National Monument 

Parks with limited surface water monitoring resources: 

 Congaree National Park 

 Kennesaw Mountain National Battlefield Park 

 Moores Creek National Battlefield 

Parks with greater surface water monitoring resources: 

 Timucuan Ecological & Historical Preserve 

 Fort Matanzas National Monument 

 Fort Frederica National Monument 
76 

Parks with adequate flow monitoring provided by USGS: 

 Horseshoe Bend National Military Park 

 Chattahoochee River National Recreational Area 

 Fort Sumter National Monument 

 Fort Frederica National Monument 

 Ocmulgee National Monument 
77 

Table 18. Recommendations for SECN parks for future surface water monitoring needs. 

Park 

Current 

Monitoring? Recommendation 

CHAT Yes none 

CONG Yes Recommend adding discharge monitoring to gages within the park. Additional 

monitoring needed to assess influence of nearby development and dam re-licensing. 

FOFR No Gage height monitoring and records maintained by USGS. 

FOMA No No data is currently being kept for FOMA and there are large gaps in the historical data 

which only reports the mean height. Recommend gage height monitoring that includes, 

min/max and mean height. 

FOPU No Although there are not any gages on FOPU, the current issues of the dredging of 

Savannah Harbor have revealed a large amount of data. However, to adequately 

monitor what happens at FOPU, min/max and mean gage height monitoring is 

recommended. 

FOSU No Nearby gage (USGS 021720711) is currently recording min/max and mean gage height, 

however heights are much greater than the data collected at the same time previously 

on FOSU. Recommend re-instating the gage height monitoring. 

HOBE Yes none 

KEMO Yes Monitor discharge in addition to gage height 

MOCR No Implement staff gage to record peak flood events. 

OCMU No Nearby gage (USGS 02213000) in Macon provides sufficient monitoring of the 

Ocmulgee River, however staff gages recommended for Walnut Creek. 

TIMU No Nearby gage (USGS 02246500) on the St. Johns may provide sufficient monitoring as 

data previously collected at TIMU shows similarities in gage heights. However, the best 

information will come from re-instating gage height monitoring at TIMU. 

79 

Bibliography 

Adams, S. M. and C. T. Hackney. 1992. Ecological processes in southeastern United States 

aquatic ecosystems. Pages 3-17 in C. T. Hackney, S. M. Adams, and W. H. Martin, 

Biodiversity of the southeastern United States: aquatic communities. John Wiley & Sons, 

New York, NY. 

Alexander, C. 2008. Rates and Processes of Shoreline Change at Fort Pulaski National 

Monument. A Study Prepared for Fort Pulaski National Monument Cockspur Island, 

Georgia. 

Barlow, P. M. 2003. Ground water in freshwater-saltwater environments of the Atlantic Coast. 

U.S. Geological Survey, Circular 1262. 

Baron, J. S., N. L. Poff, P. L. Angermeier, C. N. Dahm, P. H. Gleick, Nelson G. Hairston, Jr., R. 

B. Jackson, C. A. Johnston, B. D. Richter, and A. D. Steinman. 2002. Meeting Ecological 

and Societal Needs for Freshwater. Ecological Applications 12:1247-1260. 

Beard, L. R. 1974. Flood flow frequency techniques. TECHNICAL REPORT CRWR-119, 

OCTOBER 1, 1974. 216 P. 

Bratton, S. P. 1985. The Vegetation History of Fort Frederica, Saint Simons Island, Georgia. 

Castanea 50(3):133-145. 

Brekke, L. D., J. E. Kiang, J. R. Olsen, R. S. Pulwarty, D. A. Raff, D. P. Turnipseed, R. S. Webb, 

and K. D. White. 2009. Climate change and water resources management—A federal 

perspective: U.S. Geological Survey Circular 1331, 65 p. 

Conrads, P. A., E. A. Roehl, R. C. Daamen, and W. M. Kitchens. 2006. Simulation of water 

levels and salinity in the rivers and tidal marshes in the vicinity of the Savannah National 

Wildlife Refuge, coastal South Carolina and Georgia: U.S. Geological Survey Scientific 

Investigations Report 2006–5187, 134 p.; available online at 

http://pubs.usgs.gov/sir/2006/5187/. 

Conrads, P. A., T. D. Feaster, and L. G. Harrelson. 2008. The effects of the Saluda Dam on the 

surface-water and ground-water hydrology of the Congaree National Park Flood Plain, S.C. 

USGS Scientific Investigations Report 2008-5170. 

Dowd, J. F. 2009. Program River 2 and Update SW. The University of Georgia. Athens, GA, 

USA. 

Doyle, T.W. 2009. Modeling Flood Plain Hydrology and Forest Productivity of Congaree 

Swamp, South Carolina. U.S. Geological Survey Scientific Investigations Report 2009-5130, 

46p. 

Graf, W. L. and L. J. Stroup. 2006. Congaree floodplain decision support project: assessing the 

extent of river regulation effects on resources within and around Congaree National Park Part 
80 

1: Literature review. National Park Service Report. Piedmont – South Atlantic Coop. 

Ecosystems Studies Unit. Ref. No. R5240050013. 

Graf, W. L. and Meitzen K. M. 2006. Congaree floodplain decision support project: assessing the 

extent of river regulation effects on resources within and around Congaree National Park. 

Part II: Floodplain inundation modeling using HEC-RAS and GIS. National Park Service 

Report. Piedmont – South Atlantic Coop. Ecosystems Studies Unit. Ref. No. R5240050013. 

Hackney, C. T. and S. M. Adams. 1992. Aquatic communities of the southeastern United States: 

past, present, and future. Pages 747-760 in C. T. Hackney, S. M. Adams, and W. H. Martin, 

editors. Biodiversity of the southeastern United States: aquatic communities. John Wiley & 

Sons, New York, NY. 

Hodgkins, G.A., Dudley, R.W., and Aichele, S.S., 2007, Historical changes in precipitation and 

streamflow in the U.S. Great Lakes Basin, 1915–2004: U.S. Geological Survey Scientific 

Investigations Report 2007–5118, 31 p. (Also available online at 

http://pubs.usgs.gov/sir/2007/5118.) 

Hodgkins, G.A., Dudley, R.W., and Huntington, T.G., 2003, Changes in the timing of high river 

flows in New England over the 20th century. Journal of Hydrology, v. 278, p. 242–250. 

Knowles, N., Dettinger, M., and Cayan, D., 2006, Trends in snowfall versus rainfall for the 

western United States: Journal of Climate, v. 19, no. 18, p. 4,545–4,559. 

Knowles, D. B., M. M. Brinson, R. A. Clark, and M. D. Flora. 1996. Water Resources 

Management Plan Congaree National Park. National Park Service United States Department 

of the Interior. Cooperative agreement number CA-5240-3-9002/1. 

Kundzewicz, Z.W., L.J. Mata, N.W. Arnell, P. Döll, P. Kabat, B. Jiménez, K.A. Miller, T. Oki, 

Z. Sen and I.A. Shiklomanov, 2007: Freshwater resources and their management. Climate 

Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to 

the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. 

Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge 

University Press, Cambridge, UK, 173-210. 

Kunkle, S. and D. Vana-Miller. 2000. Water Resources Management Plan Chattahoochee River 

National Recreation Area. Chattahoochee National Recreation Area, GA. 

Mallin, M. A., and M. R. McIver. 2007. Assessment of Water Resources and Watershed 

Conditions in Moores Creek National Battlefield, North Carolina. In Press. Center for 

Marine Science University of North Carolina Wilmington, Wilmington, N.C. 28409. 

Mathews, R., and B. D. Richter. 2007. Application of the Indicators of Hydrologic Alteration 

Software in Environmental Flow Setting. JAWRA Journal of the American Water Resources 

Association 43:1400-1413. 
81 

Mathews, R., and B. D. Richter. 2007. Application of the Indicators of Hydrologic Alteration 

Software in Environmental Flow Setting. Journal of the American Water Resources 

Association 43:1400-1413. 

McFarlin, C., and M. Alber. 2005. Assessment of Coastal Water Resources and Watershed 

Conditions at Fort Pulaski National Monument., Georgia. National Park Service, Water 

Resources Division. Natural Resources Program Center. Technical Report 

NPS/NRWRD/NRTR-2005/345. 

Meehl, G.A., T.F. Stocker, W.D. Collins, P. Friedlingstein, A.T. Gaye, J.M. Gregory, A. Kitoh, 

R. Knutti, J.M. Murphy, A. Noda, S.C.B. Raper, I.G. Watterson, A.J. Weaver and Z.-C. 

Zhao, 2007: Global Climate Projections. In: Climate Change 2007: The Physical Science 

Basis. Contribution of Working Group I to the Fourth Assessment Report of the 

Intergovernmental Panel on Climate Change [Solomon, S.,D. Qin, M. Manning, Z. Chen, M. 

Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, 

Cambridge, United Kingdom and New York, NY, USA. 

Merdun, H., J.C. Hayes, and D.E. Linvill. 1996. Statistical Analysis of Flows into Congaree 

Swamp National Monument. Interim Report. Department of Agriculture and Biological 

Engineering. Clemson University. 

Merdun, H. 2003. Studies on the Flood Analysis of the Congaree National Park. KSU Journal of 

Science and Engineering 6(2):130-141. 

Miller, K., and Yates, D., 2006, Climate change and water resources—A primer for municipal 

water providers: Denver, Colo., American Water Works Association, 83 p. 

National Park Service. 1997b. Baseline water quality data inventory and analysis, Horseshoe 

Bend National Military Park. U.S. National Park Service, Technical Report 

NPS/NRWRD/NRTR-97/142, Fort Collins CO. 

National Park Service. 1997c. Baseline water quality data inventory and analysis, Moores Creek 

National Battlefield. U.S. National Park Service, Technical Report NPS/ NRWRD/NRTR97/120, Fort Collins CO. 

National Park Service. 1998a. Baseline water quality data inventory and analysis, Fort Frederica 

National Monument. U.S. National Park Service, Technical Report NPS/NRWRD/NRTR98/155, Fort Collins CO. 

National Park Service. 1998b. Baseline water quality data inventory and analysis, Fort Matanzas 

National Monument. U.S. National Park Service, Technical Report NPS/ NRWRD/NRTR98/171, Fort Collins CO. 

National Park Service. 1999. Baseline water quality data inventory and analysis, Fort Pulaski 

National Monument. U.S. National Park Service, Technical Report NPS/NRWRD/NRTR99/250, Fort Collins CO. 
82 

National Park Service. 2000. Baseline water quality data inventory and analysis, Timucuan 

Ecological and Historic Preserve. U.S. National Park Service, Technical Report 

NPS/NRWRD/NRTR-2000/278, Fort Collins, CO 

National Park Service. 2001a. Baseline water quality data inventory and analysis, Ocmulgee 

National Monument. U.S. National Park Service, Technical Report NPS/ NRWRD/NRTR2001/288, Fort Collins CO. 

National Park Service. 2001b. Baseline water quality data inventory and analysis, Fort Sumter 

National Monument. U.S. National Park Service, Technical Report NPS/ NRWRD/NRTR2001/283, Fort Collins CO. 

Olden, J. D., and N. L. Poff. 2003. Redundancy and the choice of hydrologic indices for 

characterizing streamflow regimes. River Research and Applications 19:101-121. 

Patterson, G. G., G. K. Speirman, and B. H. Whetstone. 1985. Hydrology and its effects on 

distribution of vegetation in Congaree Swamp National Monument. USGS Water Resources 

Investigations Report 85-4256. 

Plewa, M. T. and W.L. Graf. 2005. Hydrologic variation of the Congaree River near Congaree 

National Park, SC. National Park Service Report. 

Richter, B., J. Baumgartner, R. Wigington, and D. Braun. 1997. How much water does a river 

need? Freshwater Biology 37:231-249. 

Soballe, D., B. Kimmel, R. Kennedy, and R. Gaugush. 1992. Reservoirs. Pages 421-474 in C. T. 

Hackney, S. M. Adams, and W. H. Martin, editors. Biodiversity of the southeastern United 

States: aquatic communities. John Wiley & Sons, New York, NY. 

Speiran, G. K., G. G. Patterson, and B. H. Whetstone. 1985. Hydrology of Congaree Swamp 

National Monument, SC. USGS Water-Resources Investigations Report. 

Stewart, I.T., Cayan, D.R., and Dettinger, M.D. 2005. Changes toward earlier streamflow timing 

across western North America: Journal of Climate, v. 18, p. 1,136–1,155. 

The Nature Conservancy. 2007. Indicators of Hydrologic Alteration Version 7 User's Manual. 

Tiner, R. W. 1977. An inventory of South Carolina’s coastal marshes: Office of Conservation 

and Management, South Carolina Wildlife and Marine Resources Department, Charleston, 

S.C., Technical Report Number 23, 33 p. 

USACOE. 2000. Moores Creek at Moores Creek Battlefield: Hydrology and Hydraulics 

Evaluation. U.S. Army Corps of Engineers, Wilmington District. White paper prepared for 

NPS MOCR. 
83 

Appendix A – Surface Water Data Analysis Support 

Programs 

Two programs were developed by Professor John Dowd in the Geology Department of the 

University of Georgia to support surface water analyses and can be obtained upon request 

(jdowd@uga.edu). The two programs are UpdateSW, and River 2 which are described below. 

Program UpdateSW

This program is designed to assist in the management and interpretation of surface water data. 

The program updates daily or real time USGS streamflow or groundwater data by using the 

internet to update chosen gage sites, and saving the data in an Excel format. The program can 

also be used to graph the data, and to evaluate whether temporal trends are present in the data. 

Surface water data (discharge and stage) is used for a trend analysis for each park. The trend 

analysis was completed by retrieving all discharge or water level data for a list of gaging stations 

that were determined to be representative of the surface water conditions in the SECN NPS parks 

of interest. 

UpdateSW can be used to download data from the National Water Information System (NWIS) 

database, which is the national archive for hydrologic data (http://nwis.waterdata.usgs.gov/nwis). 

NWIS combines local databases with the centralized National Water Data Storage and Retrieval 

System (WATSTOR) database to create a single, distributed-information processing and 

management system (Dzurik, 2002). 

Surface water and groundwater data collected is accessed from the NWIS database using: 

http://water.usgs.gov/waterwatch/

http://ogw01.er.usgs.gov/AWLSites.asp?S=<stationid> 

where <stationed> is the USGS station identification. UpdateSW stores data as an Excel file. 
84 

Running UpdateSW 

1. Double-click setup_UpdateSW1200.exe and run InstallShield Wizard to install 

UpdateSW (Figure A-1). Then repeat the process for setup_River2V2013.exe to install 

River2. Both programs will be downloaded to C:\Program Files\HOTL\ 

Figure A-1. Program InstallShield Wizard - Sample screen showing the installation process 

2. Navigate to C:\Program Files\HOTL\ and open UpdateSW.exe (Figure A-2). 

Figure A-2. Program UpdateSW - Sample screen showing how UpdateSW appears when first opened. 
85 

3. Click File on the Menu Bar then Read. 

4. In the Open window navigate to the UpdateSW folder and select the .txt file that 

corresponds to the state in which the gage station of interest is located (Figure A-3). For 

instance GA_SW_UV.txt will extract the data for the USGS gage stations in Georgia. 

NC_SW_UV.txt will extract the data for the USGS gage station in North Carolina. Then 

click Open. 

Figure A-3. Program UpdateSW - Sample screen showing how UpdateSW appears when first opened. 
86 

5. In the Update Gage Data frame all of the gage station for the state will appear (Figure A4). Here select the gage stations of interest and the Data Type. Daily values extract the 

average daily values for the site for the entire period of collection. Real time extracts the 

15-minute data but only for the past 60 days. 

Figure 55. Program UpdateSW - Sample screen showing the display using the Read option. 

6. Click on Process 

7. After the data is processed you can close UpdateSW. 
87 

UpdateSW has a number of other functions, below is a detailed description of them. 

File Command 

 Read: Initially, this option will allow the user to navigate to the appropriate file. When 

re-starting the program, it will open the last gage list file read, containing a list of sites. 

The first time the program is run, the user must navigate to the input file. A list of sites to 

be updated must be in a text file in the following format: 

02191300 BROAD RIVER ABOVE CARLTON, GA 

02192000 BROAD RIVER NEAR BELL, GA 

with the site identification number first, followed by a description of the site. An example 

file, filelist.txt, is supplied with the program. 

A mixture of surface water and groundwater sites is acceptable. The file GageList.txt is 

supplied as an example. The list can be modified with the Add command. It is preferable 

to use the Add option to maintain the list because an improper site number will cause 

uncertain results from the website. 

 New: This option allows the user to navigate to a new text file that contains a list of site 

names to be maintained. The file GageList.txt is supplied as an example. The list can be 

modified with the Add command. It is preferable to use the Add option to maintain the 

list because an improper site number will cause uncertain results from the website. This 

command allows the user to navigate to a new file name and/or location. 

 Filenames: This form allows the user to change the filenames associated with the sites 

(Figure A-5). The default name is a “G” followed by the site number. Names can be 

modified by typing a new name (without extension) and pressing the <enter> key. The 

list will be saved with the Update option, or discarded with the Cancel option located in 

the drop-down menu below File in the Gage File Names window. Default names can be 

obtained with the Default option. The Filename option allows the user to specify the 

filename that contains the list of names associated with the sites in the gage list. 
88 

Figure 56. Program UpdateSW - Sample screen showing the display using the Filenames option. 

 Add: The current file list can be modified with this form, and appears in the right panel 

(Figure A-6). A Master List can be loaded to the left side with the Load option located in 

the drop-down menu under File in the Add Station window. The real-time surface water 

sites for Georgia, for example, are contained in GA_SW_UV.txt, and real-time 

groundwater sites for Georgia are contained in GA_GW_UV.txt. Sites can be added to the 

operational list by dragging sites to the right. Only valid sites can be dragged. Sites can 

be removed by dragging sites from the operational list to the left. The Master List will not 

be permanently modified by this action. Upon return, if the file list is modified, the 

program will display the filenames form. 

Figure 57. Program UpdateSW - Sample screen showing the display using the Add option. 
89 

 View: This option allows the user to inspect the last file downloaded and the full Excel

spreadsheet (Figure A-7). The site is selected from the list at the bottom; the daily values 

or real-time values are selected with the adjacent button. The Excel file can be modified 

by the following sequence: select a cell with the mouse, change the value, press the 

<enter> key. If the file is changed, the user can select to save the changes when the View

form is closed. A sample screen showing the program operation is provided below. 

Figure 58. Program UpdateSW - Sample screen showing the display using the View option. 

 Exit: Exit the program. Various defaults are set when exited in this manner. If the "x" is 

used to exit the program, these defaults will not be set. 
90 

Graph Command 

 Graph: To view a Cartesian plot of the data in the Update Gage Data window click 

Graph from the menu bar (Figure A-8). When the Graph window appears a site is 

selected from the drop down list box at the bottom of the Form. A button is used to select 

between daily and real-time values. The Plot button will display the selected site. If both 

discharge and gage height data exists then discharge will be plotted on the left axis and 

gage height will be plotted on the right axis. For groundwater, depth below surface will 

be plotted. The Graph > Options menu item allows other data to be plotted. 

Figure 59. Program UpdateSW - Sample screen showing the display using the Graph option. 
91 

 Edit: This option allows the user to manually change most aspects of the plot, including 

line color and axis labels (Figure A-9). Printing can also be accomplished from this 

option. 

Figure 60. Program UpdateSW - Sample screen showing the display using the Edit option in the Graph

window. 

 View: This option allows the user to inspect the data in a full Excel spreadsheet. The site 

is selected from the list at the bottom; the daily values or real-time values are selected 

with the adjacent button. The Excel file can be modified by the following sequence: 

select a cell with the mouse, change the value, press the <enter> key. If the file is 

changed, the user can select to save the changes when the View form is closed. 
92 

 Options: This option, located in a drop-down menu under Graph, allows the user to 

select any data to be plotted on the left or right axis (Figure A-10). The list box for each 

axis lists all the data contained in the Excel file. This option also contains an edit box to 

change the time gap for plotting breaks in the data. 

Figure 61. Program UpdateSW - Sample screen showing the display using Options in the Graph 

window. 

 Plot Fast: The curves are broken if there is a gap in the data (default). The magnitude of 

the time gap can be changed in Options menu option. The Plot Fast option will plot the 

data without the breaks. It is not reliable if there is a large break in the data. 

 Cursor: This option displays a mouse cursor, and shows the cursor position at the top of 

the plot. The x-axis is shown as Date/Time, and the y-axis is shown in units of either the 

left or right axis. T 

 Alternate: This option allows the user to alternate the cursor between the left and right 

axis. Initially, the cursor points to the left y-axis. This option is only available when the 

cursor is turned on. 

 Flip Series: the flip button will alternate between the two curves. 
93 

 Show Point : This command displays all the individual data points on the graph 

 Copy to Clipboard: This option is the easiest way to save a copy of the plot. If a 

graphics capable program is also running, selecting this option will place a copy of the 

graph in the clipboard. In the other program, paste will place the copy in the program. 

 Trend: For daily values of groundwater (depth below surface), the annual average depth 

and annual trend can be shown with the Trend option in the Main menu. The year is 

calculated from January 1. In order to provide a statistically significant result, the test 

requires a minimum number of daily observations per year, and a minimum number of 

years of monitoring data overall. These values can be modified on the Options menu. 

Program River 2

River2 is designed to display streamflow, and summarize the data using several statistical 

techniques. These procedures include flow duration curve using a log normal distribution, and 

high and low flows using several extreme value distributions. The annual series for these 

distributions is displayed in tables 

The program reads data in an Excel spreadsheet that was produced by the UpdateSW program 

(daily data read from the USGS website). In addition, daily flow from the UK equivalent 

(National River Archive: http://www.ceh.ac.uk/data/nrfa/river_flow_data.html) can also be read. 

The file Tamar.xls is an example of this data type. Note that these data must be converted from 

the .csv format to the .xls format before they can be used. Daily data from other sources need to 

be put in one of these formats. If the data is in .cfs, use the USGS format; if the data is in cumecs 

(cubic meters per second), use the UK format. 

After the data is read, all calculations are performed and the different views of the data can be 

selected with the tabs at the top. In most of the views, there are multiple plot options selected 

with a drop down menu. If options are changed on the Info page, the Update button must be 

selected to perform the recalculations. 

Files 

 USGS: This program currently reads average daily flows from an Excel file produced by 

the UpdateSW program. It is an Excel file, with date/time (decimal format permissible) in 

one column, and discharge in the next column. Above the date column in row 1, the code 

60 (USGS code) denotes flow. The program selects the column headed by this column, 

which need not be in column 1. The second code on row two must be there, but is not 

used by this program. 

 UK: Data from the National River Archive 

(http://www.ceh.ac.uk/data/nrfa/river_flow_data.html) can also be read after it has been 

converted from the .csv format to the .xls format. The data on the first line is used to label 

the data, and the flow data is read starting at line 2. The data must be in the day, month, 

year, flow, code format. 
94 

 Other: If data is used from another source, it needs to be put in an Excel spreadsheet in 

the same form as one of the examples included with this program - either USGS or UK. 

Choose the one with the appropriate units, or change the units with the Edit option. 

Running River2 

1. Navigate to C:\Program Files\HOTL\ and click on River2.exe. The Open Gage 

Description File will open (Figure A-11). 

Figure 62. Program River2 - Sample screen showing how to open the GageDesc.txt file. 
95 

2. Navigate to C:\Documents and Settings\administrator\My Documents\River2 Data and 

select GageDesc.txt. Click Open. The River II window should appear (Figure A-12). 

Figure 63. Program River2 - Sample screen showing how River2 appears when first opened. 

3. In the River II window click File. In the drop-down menu click Read. The Open Gage 

File Window should appear (Figure A-13). 

Figure 64. Program River2 - Sample screen showing navigating to the gage xls files. 
96 

4. Select the .xls file associated with the gage you selected in UpdateSW. Then click open. 

The River II window will update with the gage data added and the Info tab will be 

selected. 

5. Different views are selected with the tabs at the top of the page (Figure A-14). These 

include Info, Flow, Tables, High Flow, Flow Duration Curve, Low Flow, Seasonal, and 

Annual 

Figure 65. Program River2 - Sample screen showing the Info tab as River2 appears after it has read the 

.xls file. 

Info Tab 

The Info tab contains the calculation options that determine how the plots are created. 

 Gage Number/Description: The USGS gage number, with accompanying description is 

shown in the Gage# and Description box at the top of the screen. The gage number is 

read in from the file name, and the gage description is found in the GageDesc.txt file. 

These are read only fields and cannot be edited.

 Record Information: In the Record Information box, the start date and end dates of the 

data collected by the USGS are shown. These are read only fields and cannot be edited.
97 

 Record Set: In the Record Set box, the start date and end dates of the data analyzed with 

the program can be adjusted to a specific period of record. 

o Start Time: The start date for the data to be analyzed can be set with this field. 

This can be done by typing the desired date in the date field, or by using the 

calendar button. If a date is set that is before the Start Date in the Record 

Information box then the value is automatically reset to the Start Date in the 

Record Information box.

o End Time: The end date for the data to be analyzed can be set with this field. 

This can be done by typing the desired date in the date field, or by using the 

calendar button. If a date is set that is after the End Date in the Record 

Information box then the value is automatically reset to the End Date in the 

Record Information box.

o Number of Multi-Days: The number of days in a moving average multi-day 

calculation can be specified in this field. 

 Log-Pearson III Options Regional Skew: Options for the Log-Pearson III calculations 

are set in this box. 

o High-flow Regional Skew: The regional skew for high flow is entered in this 

field. The skew map for the US can be shown with the speed button located 

beside the High-flow Skew Type drop down menu (Figure A-15). 

Figure 66. Program River2 - Sample screen showing the high-flow regional skew map. 
98 

o High-flow Skew Type: The skew calculation is set with this drop down menu. 

 Station skew will be the skew calculated from the data. This should be 

used for long datasets. It is generally used for datasets of over 100 years 

 The Regional skew entered in the field above will be used in calculations 

if this option is chosen. This option should be used for stations with a 

short record. It is generally used for datasets of less than 25 years. 

 The Automatic option will use a weighted average of the station and 

regional skews, depending on the length of record. For record lengths less 

than 25 years, the regional skew will be used, and for lengths longer than 

100 years the station skew will be used. It is recommended that Automatic 

always be used and that the correct regional skew be entered into the Log 

Person Options Regional Skew box. 

o Low-flow Regional Skew: The regional skews for low flow are entered in this 

field. There is no US map available for low-flow skews. 

o Low-flow Skew Type: The skew calculation is set with this drop down menu. 

 Station skew will be the skew calculated from the data. This should be 

used for long datasets. It is generally used for datasets of over 100 years 

 The Regional skew entered in the field above will be used in calculations 

if this option is chosen. This option should be used for stations with a 

short record. It is generally used for datasets of less than 25 years. 

 The Automatic option will use a weighted average of the station and 

regional skews, depending on the length of record. For record lengths less 

than 25 years, the regional skew will be used, and for lengths longer than 

100 years the station skew will be used. 

 NOTE: Low-flow regional skew maps are not available. 

 Annual Series: Options for the annual series are set in this box. 

o Minimum Number of Days: The minimum number of days entered in this field 

will be used to filter the annual series. If fewer days are available for the 

calculation of the annual series (high, low or multi-) than in this field, the year 

will be skipped. 

 NOTE: Single days missing in the record are interpolated with a linear 

interpolation of the adjacent days. Consequently they are not counted as 

missing days 

o High-flow Start Day: This field sets the start date for the high-flow water year. It 

can be edited directly or with the adjacent calendar tool. 
99 

o Low-flow Start Day: This field sets the start date for the low-flow water year. It 

can be edited directly or with the adjacent calendar tool. 

o Plotting Formulas: The plotting formulas for the high-flow and low-flow 

calculations are set with the appropriate drop down menu. Plotting formulas 

available are: 

Weibull n+1 / i 

Hazen n / i-0.5 

Gringorten n+0.12 / i-0.44 

Blom n+0.25 / i-(3/8) 

Bernard n+0.4 / i-0.3 

Beard n+0.38 / i-0.31 

Where n is number of years of data in the annual series, and i is the rank. If in 

doubt, it is suggested you use the Weibull formula, which is set as the default. 

 Update Button: This button must be "clicked" to recalculate the data with the choices 

made on this page. Therefore, it is important to Update after before looking at any graphs 

or tables if a change was made. No re-calculation is performed if this button is not 

selected.

Figure 67. Program River2 - Sample screen showing the Flow tab. 
100 

Flow Tab 

The Flow tab displays the daily flow (Figure A-16). 

 Flow: Areas of interest can be selected with the Graph->Zoom X-Axis option. The 

desired start and end times can be set with the edit fields or with the (vertical) cursor, 

which is displayed if the appropriate radio button is selected. If the cursor is not found, 

double click with the mouse and the cursor will follow the mouse. Another double click 

will freeze the cursor, and it will have to be "grabbed" with the mouse to move it. The 

start date must be before the end date. After the ends are selected, the plot is rescaled 

with the zoom button. The resulting plot can be rescaled with the same procedure. The 

full button will re-plot all of the daily flows. 

 Daily Flow: The daily flow option on the drop down menu at the top of the graph will 

plot the daily flows. The vertical scale can be reset with the Edit menu option. The time 

scale is most easily reset with the Zoom X-Axis menu item.

 Multi-Day Flow: The multi-day flow option on the drop down menu at the top of the 

plot will plot the moving average multi-day flows. The vertical scale can be reset with the 

Edit menu option. The time scale is most easily reset with the Zoom X-Axis menu item.

 Both Flows: Both flows can be shown with this option. The red line is the daily flow, 

and the black line is the multi-day flow.

Figure 68. Program River2 - Sample screen showing the Tables tab. 
101 

Tables Tab 

The Tables tab displays the high and low-flow annual series (Figure A-17). It also displays the 

skew used for the Log-Person III calculation for each annual series in a box at the bottom of the 

window. 

 High Flow: The high-flow annual series is shown in the left table. Initially it is sorted in 

descending order. The left column is the year, the middle column is the maximum flow 

for that year, and the right column is the number of days examined for that year. The 

button at the bottom will toggle the table between sorting by year in ascending order and 

sorting by flow in descending order.

 Low Flow: The low-flow annual series is shown in the middle table. Initially it is sorted 

in ascending order. The left column is the year, the middle column is the minimum flow 

for that year, and the right column is the number of days examined for that year. The 

button at the bottom will toggle the table between sorting by year in ascending order and 

sorting by flow in ascending order.

 Low-flow Multi-Day Series: The moving average multi-day low-flow annual series is 

shown in the right table. The number of days used in the calculation is selected on the 

Info page. Initially it is sorted in ascending order. The left column is the year, the middle 

column is the minimum multi-day flow for that year, and the right column is the number 

of days examined for that year. The button at the bottom will toggle the table between 

sorting by year in ascending order and sorting by flow in ascending order.

Figure 69. Program River2 - Sample screen showing the High Q tab. 
102 

High-Q Tab 

The High Q tab shows the high-flow extremal analysis (Figure A-18). 

 High Flow: The circles represent the flow of the annual series plotted with the Weibull 

plotting formula n+1/m, where n is the number of years in the series, and m is the rank. 

The solid line is the best fit of the statistical distribution chosen in the drop down menu in 

the upper left. (It is calculated by the method of moments.) The curve is best interpolated 

with the Cursor, enabled from the main menu. When enabled, the flow and the return 

period in years are shown in the upper right corner of the plot. 

o Gumbel I: Gumbel I high-flow analysis. 

o Log-Pearson III: Log-Pearson III high-flow analysis. The skew calculation is 

determined by choices on the Info page.

o Independence: The annual series verse the value for the next year is plotted in 

this view. Unacceptable serial correlation can be corrected by choosing another 

start date for the high flows on the Info page. 

Figure 70. Program River2 - Sample screen showing the FDC tab. 
103 

FDC Tab 

In the FDC tab the flow duration curves are plotted (Figure A-19). The squares are calculated 

from the daily flow, with twenty evenly spaced bins determined from the log of the flows. The 

straight line is the best fit of the log-normal distribution from the daily flow data using the 

maximum likelihood estimator. 

 Single Day: Single day flows are used for the calculation in this view. 

 Multi Day : Moving average multi-day flows are used for the calculation in this view. 

The number of days in the calculation is set on the Info page. 

 Both Plots: Both single day and multi-day flows are shown in this view. The green 

values are from the single day flows, and the red values are from the multi-day flows. 

The number of days in the multi-day flow calculation is set on the Info page. 

Figure 71. Program River2 - Sample screen showing the Low Q tab. 

Low Q Tab 

The Low Q tab shows the low-flow extremal analysis (Figure A-20).

 Low Flow: The circles represent the flow of the annual series plotted with the Weibull 

plotting formula n+1/m, where n is the number of years in the series, and m is the rank. 

The solid line is the best fit of the statistical distribution chosen in the drop down menu in 

the upper left. (It is calculated by the method of moments.) The curve is best interpolated 
104 

with the Cursor, enabled from the main menu. When enabled, the flow and the return 

period in years are shown in the upper right corner of the plot.

o Gumbel I- Single Day: Gumbel I low-flow analysis using single day data. 

o Log-Person III- Single Day: Log-Pearson III low-flow analysis using single day 

data. The skew calculation is determined by choices on the Info page. 

o Independence: The annual series versus the value for the next year for the single 

day low-flow annual series is plotted in this view. Unacceptable serial correlation 

can be corrected by choosing another start date for the low flows on the Info page. 

o Gumbel I- Multi-Day: Gumbel I low-flow analysis using multi-day data. The 

number of days in the multi-day flow calculation is set on the Info page. 

o Log-Pearson III- Multi-Day: Log-Pearson III low-flow analysis using multi-day 

data. The skew calculation is determined by choices on the Info page. The number 

of days in the multi-day flow calculation is set on the Info page. 

Seasonal Tab 

The seasonal tab shows the minimum seasonal flows for each year (Figure A-21). 

 Seasonal: The minimum daily flow is show in the seasonal tab for January, February, 

June and July. The Lin Slope column is filled in form the accepted values decided upon 

by the user in Annual Tab 

Figure 72. Program River2 - Sample screen showing the Seasonal tab. 
105 

Annual Tab 

The Annual tab is used to look at all the data for a single year within the data record (Figure A22). 

 Annual: Looks at the data for a single year. The user can move between years with the 

left and right arrow buttons located under the graph. 

o Pick: Allows the user to select several data points. The data points that are 

selected should try and represent the base flow for the river during that year. 

o Analyze: This command plots a best-fit line for the points selected for the points 

that were selected. 

o Line Slope: The line slope is calculated from the best-fit line. If the user would 

like to save this as the line slope for the base flow for that year then the user can 

select ‘Accept’. When the user hits ‘Accept’ the line slope value is added to Lin 

Slope column on the table in the Seasonal tab. If the user does not feel that the 

slope an accurate computation for the annual base flow then the user should click 

‘Reject’ and select new points. 

Figure A-22. Program River2 - Sample screen showing the Annual tab. 

107 

Appendix B – Streamflow Measurement Procedure 

Measuring streamflow is important in understanding and predicting the probability of flood and 

drought conditions. The easiest way to measure streamflow is to install a gage and establish a 

stage-flow curve. 

When selecting a gaging station site the hydrology of the area should be considered. An ideal site 

for a gaging station is an area where the stream is straight for 300 ft above and below the station 

and is easily accessible. It is also it preferable that the flow be restricted to a single channel at all 

stages. Wetland areas are not ideal because there is so much subsurface flow that bypasses the 

channel. The banks should be stable and high enough to contain floods. This is important for 

maintaining a constant cross-section and it is for this same reason that sites where the streambed 

is prone to scour or fill are sought. If possible, there should be some natural channel controls 

such as bedrock outcrops with no aquatic growth. Artificial channel controls can be installed if 

natural ones are not present. The site should be selected far enough upstream of any confluence 

to avoid influences on the stage height. It is rare to find a stream location that meets all of these 

requirements within the park boundaries, therefore common sense must be used in selecting a 

site. Bridges make good gaging station sites because they are extremely accessible and often the 

embankments are paved so the cross section remains constant. 

After a site has been selected, a datum plane must be established. The datum plane is established 

to verify that the channel morphology has not changed. If the stream-channel changes, then a 

new rating curve must be established or a coefficient can be applied to the old rating curve to 

account for the new channel cross-section. The datum can be arbitrarily set to when the 

streamflow is zero, the bottom of the channel, or the datum can be based on the elevation above 

sea level. In order to maintain a permanent datum at the gaging location at least 2 or 3 reference 

marks should be selected. Reference marks are permanent points, independent of the gage 

structure, with a known gage height elevation. Every so often the gage structure should be 

compared with the reference marks to ensure accurate data collection. 

After a datum is established, the staff gage should be installed on a secure structure in the stream 

(Figure B-1). Staff gages look like large steel plated measuring tapes that are marked to 

hundredth of a foot for accuracy. At the selected cross-section where the gage is located the flow 

velocity must be measured. To get a precise streamflow velocity measurement the flow must be 

taken at several verticals across the stream using a current meter or a flow meter (Figure B-2). 

The general rule for determining the number of verticals to measure is based on stream width. 

The stream width is measured from bank to bank at right angles to the flow direction with a 

measuring tape. If the stream width is less than 5 ft, then verticals should be spaced .5 ft apart; if 

the stream is greater than 5 ft, 20 to 30 verticals are ideal but a minimum of 10 is required. To 

determine each location to use to measure the flow, take the entire stream length and divide it by 

the number of verticals to be measured to give the distance between verticals. Then take that 

distance and divide it by two. This will give you the distance from the bank for taking your first 

flow reading. For each additional flow reading add the distance between verticals. For instance, 

if your stream width is 10 ft and you decide to do 15 verticals, then the distance between 

verticals would be .67 ft and your first point would be at .33 ft from the bank. The second point 

would be at 1 ft from the shore. The third point would be at 1.67 ft from the shore and so on. 
108 

Figure 73. Staff gage positioned vertically to monitor river stage. 
109 

Figure 74. Channel measurements required for determining stream discharge. 

The current meter or flow meter should be set to record the velocity at 60% of the stream depth, 

if the depth at that location is less then 2.5ft. If the depth is greater than 2.5 ft, then the velocity 

should be measured at 20% and 80% of the stream depth then the two velocity measurements are 

averaged together. Once velocity measurements are collected for each vertical the flow can be 

calculated. To determine area each vertical represents the sampling depth at each location and is 

multiplied by the distance between verticals. To get the discharge at each vertical, the velocity is 

multiplied by the corresponding area. The stream’s total discharge is the sum of the discharges at 

each vertical. 

When the gage is first installed, record several flow measurements at different stages to establish 

a stage-flow curve (Figure B-3). Once the curve is established, the flow only needs to be 

measured monthly to make sure the cross section hasn’t been altered. The stage however should 

be measured twice daily and during times of rapid change. Plotting the stage against the 

discharge for a variety of flows develops the stage-flow curve. Once this relationship is 

established, a discharge rate can be determined based on the stage measurements. 
110 

Figure 75. Rating curve used to relate stage to discharge. 
111 

Appendix C- Sea Level Rise Scenarios 

Presented below are maps (Figures C-1 through C-5) of hypothetical scenarios for the effect of 

sea level rise combined with storm surge projections on coastal parks within the SECN (FOFR, 

FOMA, FOPU, FOSU, and TIMU). The Digital Elevation Models (DEM) for each park were 

downloaded from the Geospatial Data Gateway (http://datagateway.nrcs.usda.gov/). The DEMs 

were used to illustrate changes in sea level resulting from climate change (Meehl et al. 2007) and 

storm surge estimations. 

Figure 76. Projected effects of sea level rise combined with storm surge events of 1 – 5 meters on Fort 

Frederica National Monument (10 meter Digital Elevation Map cell size). 
112 

Figure 77. Projected effects of sea level rise combined with storm surge events of 1 – 5 meters on Fort 

Matanzas (30 meter Digital Elevation Map cell size). 
113 

Figure 78. Projected effects of sea level rise combined with storm surge events of 1 – 5 meters on Fort 

Pulaski National Monument (10 meter Digital Elevation Map cell size). 
114 

Figure 79. Projected effects of sea level rise combined with storm surge events of 1 – 5 meters on Fort 

Sumter National Monument (30 meter Digital Elevation Map cell size). 
115 

Figure 80. Projected effects of sea level rise combined with storm surge events of 1 – 5 meters on 

Timucuan Ecological and Historic Preserve (10 meter Digital Elevation Map cell size). 

The Department of the Interior protects and manages the nation’s natural resources and cultural heritage; provides scientific and 

other information about those resources; and honors its special responsibilities to American Indians, Alaska Natives, and affiliated 

Island Communities. 

NPS 910/106018, November 2010 
National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center

1201 Oakridge Drive, Suite 150 

Fort Collins, CO 80525 

www.nature.nps.gov 

EXPERIENCE YOUR AMERICA TM