U.S. Department of the Interior U.S. Geological Survey

1. Phase 5.0 Chesapeake Bay Watershed Model: FTABLES Phase 5.0 Chesapeake Bay Watershed Model: FTABLES U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior U.S. Geological Survey

2. Stream Reach Connection Stream Reach Connection The routing of water and associated constituents through a single simulated stream reach is governed by the function table (FTABLE). The routing of water and associated constituents through a single simulated stream reach is governed by the function table (FTABLE). Stream reach characteristics: geometry, slope, and roughness Stream reach characteristics: geometry, slope, and roughness ROWS COLS *** 5 4 DEPTH AREA VOLUME DISCH *** (FT) (ACRES) (AC-FT) (CFS) *** 0.00 0.0 0.0 0.0 1.50 1040.0 1512.7 1020. 3.00 1103.0 3120.0 3279. 4.50 1166.1 4821.8 6527. 6.00 1229.1 6618.2 10683. END FTABLE700 ROWS COLS *** 5 4 DEPTH AREA VOLUME DISCH *** (FT) (ACRES) (AC-FT) (CFS) *** 0.00 0.0 0.0 0.0 1.50 1040.0 1512.7 1020. 3.00 1103.0 3120.0 3279. 4.50 1166.1 4821.8 6527. 6.00 1229.1 6618.2 10683. END FTABLE700

3. Phase 5 CB Model Phase 5 CB Model Phase 5: CB Watershed Calibration sites = 237 Watersheds = 684 Phase 5: Extended Network Calibration sites = 296 Watersheds = 899 Phase 5 Phase 5

4. GIS Application Dunne and Leopold, 1978 Manning’s Equation FTABLE/Rating Table XSECT (MD Dept. of the Environment) F-table input • Reach length (mi) • Upstream elevation (ft) • Downstream elevation (ft) • Slope of floodplain • Channel bottom width (ft) • Channel bankfull width (ft) • Channel bankfull height (ft) • Manning’s n for channel • Manning’s n for floodplain

5. Floodplain Slope Determination Floodplain Slope Determination

6. Floodplain Slope Determination Floodplain Slope Determination

7. Floodplain Slope Determination Floodplain Slope Determination

8. FTABLE – Channel Geometry FTABLE – Channel Geometry Average channel dimensions are similar for streams of a given drainage area in a region (Leopold and Maddock 1953, Dunne and Leopold 1978). Average channel dimensions are similar for streams of a given drainage area in a region (Leopold and Maddock 1953, Dunne and Leopold 1978). Bankfull Width Bankfull Width • Gather observed channel geometry • data from existing gaging stations • Gather observed channel geometry • data from existing gaging stations Bottom Width Bottom Width • Bankfull stage • Channel Survey’s • Published Values • 1.5 yr Flood Recurrence • Bankfull stage • Channel Survey’s • Published Values • 1.5 yr Flood Recurrence • Bankfull and Bottom Width • Channel Survey’s • Historical Discharge • Measurements • Bankfull and Bottom Width • Channel Survey’s • Historical Discharge • Measurements Bankfull Stage

9. Channel Geometry: Piedmont Channel Geometry: Piedmont

10. Channel Geometry: Valley and Ridge Channel Geometry: Valley and Ridge

11. Channel Geometry: Appalachian Highlands Channel Geometry: Appalachian Highlands

12. Channel Geometry: Coastal Plain Channel Geometry: Coastal Plain • Currently identifying reaches • (simulated) that reside in the • Coastal Plain (CP) • Currently identifying reaches • (simulated) that reside in the • Coastal Plain (CP) • Gather regional curve data for • the CP from U.S. Fish and • Wildlife (MD) and North • Carolina State University • Gather regional curve data for • the CP from U.S. Fish and • Wildlife (MD) and North • Carolina State University

13. Alignment between shoreline and ‘water’ is always a problem (mapped at different resolutions) • shoreline can clip out land cover values or include tidal water that should be excluded • solution: create two water categories, tidal and non-tidal water • atmospheric deposition is applied only to non-tidal waters

14. Estimating Channel Roughness Estimating Channel Roughness ( ) 1 = = 2 / 3 1 / 2 Q V A 1 . 49 R S A bkf bkf bkf bkf n bkf ( ) 1 = = 2 / 3 1 / 2 Q V A 1 . 49 R S A bkf bkf bkf bkf n = = 3 3 Qbkf Qbkf Bankfull Bankfull Disch Disch arg arg e e ft ft s s bkf ( ( )) )) ( ( ) ) = = + + R R Hydraulic Hydraulic Radius (Abkf/ Radius (Abkf/ 2 2 * * Bankfull Bankfull Stage Stage Bottom Bottom Width Width ft ft s s = = S S Channel Channel Slope Slope ( ( ) ) ( ( ) ) = = - - 2 2 A A Cross Cross Sectional Sectional Area Area Bankfull Bankfull Width Width * * Bankfull Bankfull Stage Stage ft ft bkf bkf = = n n Channel Channel Roughness Roughness Coefficien Coefficien t t at at Bankfull Bankfull bkf bkf ( ) 1 ( ) 1 = 2 / 3 1 / 2 n 1 . 49 R S A = 2 / 3 1 / 2 n 1 . 49 R S A bkf bkf Q bkf bkf Q bkf bkf

15. Next Steps Next Steps • Run stream channel regression equations for all gaged and • ungaged reaches • Calculate channel roughness coefficient for all reach segments • Compare observed and estimated values of channel roughness • Generate FTABLEs • Compare observed stage/discharge values from gaged sites to • stage/discharge values in the associated FTABLE • Identify and address reach segments where this process does • not work • Run stream channel regression equations for all gaged and • ungaged reaches • Calculate channel roughness coefficient for all reach segments • Compare observed and estimated values of channel roughness • Generate FTABLEs • Compare observed stage/discharge values from gaged sites to • stage/discharge values in the associated FTABLE • Identify and address reach segments where this process does • not work