Scientific Investigations Report 2007-5135
By Douglas L. Moyer and Mark R. Bennett
U.S. Geological Survey Scientific Investigations Report 2007-5135
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PDF Full report (6 MB) Appendix 2. XSECT Program for the Appalachian Plateaus Physiographic Province Appendix 3. XSECT Program for the Valley and Ridge Physiographic Province Appendix 4. XSECT Program for the Piedmont Physiographic Province Appendix 5. XSECT Program for the Coastal Plain Physiographic Province |
The U.S. Geological Survey (USGS), U.S. Environmental Protection Agency (USEPA), Chesapeake Bay Program (CBP), Interstate Commission for the Potomac River Basin (ICPRB), Maryland Department of the Environment (MDE), Virginia Department of Conservation and Recreation (VADCR), and University of Maryland (UMD) are collaborating to improve the resolution of the Chesapeake Bay Regional Watershed Model (CBRWM). This watershed model uses the Hydrologic Simulation Program–Fortran (HSPF) to simulate the fate and transport of nutrients and sediment throughout the Chesapeake Bay watershed and extended areas of Virginia, Maryland, and Delaware. Information from the CBRWM is used by the CBP and other watershed managers to assess the effectiveness of water-quality improvement efforts as well as guide future management activities.
A critical step in the improvement of the CBRWM framework was the development of an HSPF function table (FTABLE) for each represented stream channel. The FTABLE is used to relate stage (water depth) in a particular stream channel to associated channel surface area, channel volume, and discharge (streamflow). The primary tool used to generate an FTABLE for each stream channel is the XSECT program, a computer program that requires nine input variables used to represent channel morphology. These input variables are reach length, upstream and downstream elevation, channel bottom width, channel bankfull width, channel bankfull stage, slope of the floodplain, and Manning’s roughness coefficient for the channel and floodplain. For the purpose of this study, the nine input variables were grouped into three categories: channel geometry, Manning’s roughness coefficient, and channel and floodplain slope. Values of channel geometry for every stream segment represented in CBRWM were obtained by first developing regional regression models that relate basin drainage area to observed values of bankfull width, bankfull depth, and bottom width at each of the 290 USGS streamflow-gaging stations included in the areal extent of the model. These regression models were developed on the basis of data from stations in four physiographic provinces (Appalachian Plateaus, Valley and Ridge, Piedmont, and Coastal Plain) and were used to predict channel geometry for all 738 stream segments in the modeled area from associated basin drainage area. Manning’s roughness coefficient for the channel and floodplain was represented in the XSECT program in two forms. First, all available field-estimated values of roughness were compiled for gaging stations in each physiographic province. The median of field-estimated values of channel and floodplain roughness for each physiographic province was applied to all respective stream segments. The second representation of Manning’s roughness coefficient was to allow roughness to vary with channel depth. Roughness was estimated at each gaging station for each 1-foot depth interval. Median values of roughness were calculated for each 1-foot depth interval for all stations in each physiographic province. Channel and floodplain slope were determined for every stream segment in CBRWM using the USGS National Elevation Dataset.
Function tables were generated by the XSECT program using values of channel geometry, channel and floodplain roughness, and channel and floodplain slope. The FTABLEs for each of the 290 USGS streamflow-gaging stations were evaluated by comparing observed discharge to the XSECT-
derived discharge. Function table stream discharge derived using depth-varying roughness was found to be more representative
of and statistically indistinguishable from values of observed stream discharge. Additionally, results of regression analysis showed that XSECT-derived discharge accounted for approximately 90 percent of the variability associated with observed discharge in each of the four physiographic provinces.
The results of this study indicate that the methodology developed to generate FTABLEs for every simulated stream segment in the CBRWM is appropriate. Additionally, the methodology developed in this study can be applied to stream-channel representation in association with other modeling efforts such as Total Maximum Daily Load (TMDL) development
and other watershed-scale water-quality assessments.
Abstract
Introduction
Physical Setting
Physiography
Appalachian Plateaus Physiographic Province
Valley and Ridge Physiographic Province
Blue Ridge Physiographic Province
Piedmont Physiographic Province
Coastal Plain Physiographic Province
HSPF Function Table Development
XSECT Program
Estimation of Channel Geometry
Station Selection
Identification of Bankfull Stage
Identification of Bankfull Width and Bottom Width
Estimation of Manning’s n
Determination of Channel Slope, Floodplain Slope, and Watershed Drainage Area
Evaluation of HSPF Function Tables
Direction of Future Research
Summary and Application
Acknowledgments
References Cited
Appendix 1. XSECT Input Parameters for Chesapeake Bay Regional Watershed Model Reaches in the Appalachian Plateaus, Valley and Ridge, Piedmont, and Coastal Plain Physiographic Provinces
Appendix 2. XSECT Program for the Appalachian Plateaus Physiographic Province
Appendix 3. XSECT Program for the Valley and Ridge Physiographic Province
Appendix 4. XSECT Program for the Piedmont Physiographic Province
Appendix 5. XSECT Program for the Coastal Plain Physiographic Province
1–2. Maps showing—
1. The region included in the Chesapeake Bay Regional Watershed Model, highlighting the major river basins and the associated stream-reach network
2. Physiographic provinces represented and streamflow-gaging stations used in HSPF function table development in the Chesapeake Bay Regional Watershed Model
3. Diagram showing theoretical stream channel as represented in the XSECT program by bankfull stage (H), bankfull width (BFW), bottom width (BW), upstream elevation (US ELEV), downstream elevation (DS ELEV), and slope of the floodplain (SFP)
4–18. Graphs showing—
4. Relation of bankfull stage to basin drainage area for streamflow-gaging stations in the (A) Appalachian Plateaus, (B) Valley and Ridge, (C) Piedmont, and (D) Coastal Plain physiographic provinces
5. Regression residuals for predicted minus observed bankfull stage relative to basin drainage area in the (A) Appalachian Plateaus, (B) Valley and Ridge, (C) Piedmont, and (D) Coastal Plain physiographic provinces
6. Relation of bankfull width to basin drainage area for streamflow-gaging stations in the (A) Appalachian Plateaus, (B) Valley and Ridge, (C) Piedmont, and (D) Coastal Plain physiographic provinces
7. Regression residuals for predicted minus observed bankfull width relative to basin drainage area in the (A) Appalachian Plateaus, (B) Valley and Ridge, (C) Piedmont, and (D) Coastal Plain physiographic provinces
8. Relation of bottom width to basin drainage area for streamflow-gaging stations in the (A) Appalachian Plateaus, (B) Valley and Ridge, (C) Piedmont, and (D) Coastal Plain physiographic provinces
9. Regression residuals for predicted minus observed bottom width relative to basin drainage area in the (A) Appalachian Plateaus, (B) Valley and Ridge, (C) Piedmont, and (D) Coastal Plain physiographic provinces
10. Model observed depth-varying channel roughness for streamflow-gaged streams in the (A) Appalachian Plateaus, (B) Valley and Ridge, (C) Piedmont, and (D) Coastal Plain physiographic provinces
11. Cumulative distribution plots for observed and simulated discharge for streamflow-gaging stations in the Coastal Plain physiographic province
12. Cumulative distribution plots for observed and simulated discharge for streamflow-gaging stations in the Piedmont physiographic province
13. Cumulative distribution plots for observed and simulated discharge for streamflow-gaging stations in the Valley and Ridge physiographic province
14. Cumulative distribution plots for observed and simulated discharge for streamflow-gaging stations in the Appalachian Plateaus physiographic province
15. Relation of XSECT-simulated discharge to observed discharge for streamflow- gaging stations in the (A) Appalachian Plateaus, (B) Valley and Ridge, (C) Piedmont, and (D) Coastal Plain physiographic provinces
16. Regression residuals for simulated minus observed discharge relative to simulated discharge in the (A) Appalachian Plateaus, (B) Valley and Ridge, (C) Piedmont, and (D) Coastal Plain physiographic provinces
17. Relation of (A) bankfull stage, (B) bankfull width, and (C) bottom width to basin drainage area for streamflow-gaging stations in the Appalachian Plateaus, Valley and Ridge, Piedmont, Coastal Plain, and physiographic provinces
18. Distribution of regression residuals for predicted minus observed (A) bankfull stage, (B) bankfull width, and (C) bottom width for streamflow-gaging stations in the Appalachian Plateaus, Valley and Ridge, Piedmont, and Coastal Plain physiographic provinces
1. Example Hydrologic Simulation Program-Fortran function table
2. Required input parameters and associated format as required by the XSECT program
3. Streamflow-gaging stations and associated basin and channel characteristics used for the development of regional models to predict channel geometry
4. Regional regression equations, relating channel geometry to basin drainage area, and associated diagnostic statistics, for streamflow-gaging stations in the Appalachian Plateaus, Valley and Ridge, Piedmont, and Coastal Plain physiographic provinces
5. Descriptive statistics for field-estimated values of Manning’s roughness coefficient associated with the channel and flooplain for streamflow-gaging stations in the Appalachian Plateaus, Valley and Ridge, Piedmont, and Coastal Plain physiographic provinces
6. Equations and diagnostic statistics regression analysis relating simulated and observed stream discharge for streamflow-gaging stations in the Appalachian Plateaus, Valley and Ridge, Piedmont, Coastal Plain, and physiographic provinces
7. Regression equations, relating channel geometry to basin drainage area and associated diagnostic statistics for streamflow-gaging stations in the Appalachian Plateaus, Valley and Ridge, Piedmont, and Coastal Plain physiographic provinces
Moyer, D.L., and Bennett, M.R., 2007, Development of relations of stream stage to channel geometry and discharge for stream segments simulated with Hydrologic Simulation Program–Fortran (HSPF), Chesapeake Bay Watershed and adjacent parts of Virginia, Maryland, and Delaware: U.S. Geological Survey Scientific Investigations Report 2007–5135, 83 p.
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For further information, contact:
Mark R. Bennett, Director
U.S. Geological Survey
Virginia Water Science Center
1730 East Parham Rd.
Richmond, VA 23228
or visit our Web site at:
http://va.water.usgs.gov
U.S. Department of the Interior |
U.S. Geological Survey
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