1. Lower Cape Fear River Estuary Model Progress Report Jim Bowen, UNC Charlotte October 11, 2007 Charlotte, NC (via Centra)

2. Description of Model Application Open Boundary Elevation Cond. Lower Cape Fear River Estuary Schematic Black River, FlowBoundary Cond. Cape Fear R. Flow Boundary Cond. NE Cape Fear Flow Boundary Cond.

3. DO Conceptual Model BOD Sources Sediment Sediment O 2 Demand Cape Fear BOD Load NECF & Black R. BOD Load Muni & Ind. BOD Load decaying phytopl.

4. DO Conceptual Model BOD Sources, DO Sources Sediment Sediment O 2 Demand Ocean Inflows Surface Reaeration Phytoplank. Productivity MCFR Inflows

5. BOD Consumption DO Conceptual Model BOD Sources, DO Sources & Sinks Sediment Sediment O 2 Demand Ocean Inflows Surface Reaeration Input of NECF & Black R. Low DO Water

6. BOD Consumption DO Conceptual Model BOD Sources, DO Sources & Sinks Sediment Sediment O 2 Demand Cape Fear BOD Load NECF & Black R. BOD Load Ocean Inflows Surface Reaeration Input of NECF & Black R. Low DO Water Phytoplank. Productivity Muni & Ind. BOD Load decaying phytopl. MCFR Inflows

7. Modeling Developments 1.Finished Defining Model Grid Bottom roughness investigation Finished sizing marsh cells 2.Further Developed Salinity Boundary Condition at Estuary Mouth 3.Finished Hydrodynamic Model Calibration 4.WQ Predictions Using New Grid

8. Hydrodynamic Calibration - Summary, 8/07 Excellent agreement w/ temperature and salinity Elevation agreement (not shown) still needs some work to get predicted tidal amplitude attenuation to match observed attenuation

9. Model Grid Definition, Procedure Objective was to match tidal amplitudes at USGS Stations –Upper Estuary ( Lock and Dam 1, Black at Currie, NECF at Burgaw) –Middle Estuary (Navassa, NECF at Wilmington) –Lower Estuary (Marker 12)

10. Sizing Marsh Cells, Procedure Systematically varied grid parameters to match observed elevation data –Rougher bottoms damp tidal amplitudes –More off-channel storage in wetland cells damps tidal amplitudes

11. Step 1. Can changes in channel roughness produce desired amplitude attenuation? Used existing model grid

12. Existing Model Grid w/ changes described in August update 1004 water cells Has “marsh cells” in Black and NECF Marsh cells 2.0 m deep All cells have the same roughness See kmz file for more detail

13. Step 1. Can changes in channel roughness produce desired amplitude attenuation? Used existing model grid Varied roughness across grid –Typical value = 0.02 –Minimum = 0.015 m (very smooth) –Maximum = 0.045 m (very rough) Looked at changes in amplitude as bottom roughness increased

14. Results, Variable Bottom Roughness

15. Upper Estuary Stations Underdamped

16. Results, Variable Bottom Roughness Middle Estuary Stations Underdamped

17. Results, Variable Bottom Roughness Very little sensitivity to bottom roughness

18. Sizing Off-Channel Storage, Procedure 1.Went through model grid and resized “marsh cells” to roughly fit wetland delineations 2.Developed a method to quickly vary width and roughness of marsh cells, create EFDC grid files, and see results w/ Google Earth 3.Ran model many times w/ various marsh configurations and observed results

19. First step, try various marsh cell widths Varied marsh cell widths –Base case –Base case * 2 –Base case * 5 –Base case * 10 Determined how width changes affected tidal amplitudes

20. Base Case

21. Base Case, Width x 2

22. Base Case, Width x 5

23. Base Case, Width x 10

24. Results, Marsh Width Variation

25. Width ratio = 2.0 gives best results overall Need additional damping at Navassa Added additional marsh cells in middle estuary (V1, V2) Also tried smaller changes in marsh width (1.5, 2.0)

26. Version 1, Width x 2

27. Version 2, Width x 1.0/2.0

28. Version 3, Width x 1.5

29. Results, Tidal Amplitudes

30. Unable to match exactly the observed pattern in amplitude reduction V2, Width ratio = 2.0 (in green) determined to give the best results overall

31. Version 1, Width x 2

32. Previous Model Grid

33. New Grid Characteristics Off-channel storage locations based on wetland delineations 46 additional marsh cells added (1050 total cells) Additional off-channel storage added to each basin (Cape Fear, Black, NECF) Significant amount of marsh area added to middle and lower estuary

34. Results for New Grid Also investigated alternate boundary condition specification –Now use AM and PM max salinity at station M12 rather than daily max Now use hourly rather than 12-hour averaged monitoring data Looked at observed vs. predicted temperatures, salinities, elevations Compared results to those obtained previously w/ previous model grid

35. Elevations, Currie, June 04

36. Elevations, Burgaw, June 04

37. Elevations, Navassa, June 04

38. Elevations, NECF Wilm., June 04

39. Elevations, Mrkr 12, June 04

40. April - November 2004 Temp., 8/07

41. April - November 2004 Temp., New

42. April - November 2004 Temp., 8/07 Statistical Measures of Fit (units of deg C) mean(pred-obs) =0.10046 ME_norm =0.0043473 RMSE =0.96224 MAE =0.71269 MAE_norm =0.030841 RMSE_norm =0.041639 r_squared =0.97272 num data comparisons = 4150 r 2 adjusted for bias = 0.96465

43. April - November 2004 Temp., New Statistical Measures of Fit (units of deg C) mean(pred-obs) =0.034678 ME_norm =0.0015146 RMSE =0.95803 MAE =0.71946 MAE_norm =0.031423 RMSE_norm =0.041843 r_squared =0.97439 num data comparisons = 4579 1-mse/var(obs) = 0.96604

44. April - November 2004 Salinity, 8/07

45. April - November 2004 Salinity, New

46. April - November 2004 Salinity, 8/07

47. April - November 2004 Salinity, New

48. April - November 2004 Salinity, 8/07

49. April - November 2004 Salinity, New

50. April - November 2004 Salinity, 8/07

51. April - November 2004 Salinity, New

52. April - November 2004 Salinity, 8/07 Statistical Measures of Fit (units of PSU) mean(pred-obs) =-0.25797 ME_norm =-0.043321 RMSE =2.6493 MAE =1.6424 MAE_norm =0.27581 RMSE_norm =0.4449 r_squared =0.87049 num data comparisons = 3517 1-mse/var(obs) = 0.84804

53. April - November 2004 Salinity, 8/07 Statistical Measures of Fit (units of PSU) mean(pred-obs) =-0.0044639 ME_norm =-0.00083995 RMSE =2.64 MAE =1.5505 MAE_norm =0.29176 RMSE_norm =0.49675 r_squared =0.87044 num data comparisons = 3953 1-mse/var(obs) = 0.85345

54. Summary of Progress Model grid now includes a significant amount of off-channel storage Salinity mean errors now very low (important for predicting dilution) Tidal elevation attenuation now well simulated Hydrodynamic & conservative transport submodels now calibrated

55. Summary of Progress, cont’d Also have developed a program for animating horizontal contour in Google Earth (good for showing DO results) Benoit Duclaud finished Masters thesis on new method for predicting reaeration (thesis, paper available next month)

56. Information Available Online See LCFR website for more info www.coe.uncc.edu/~jdbowen/LCFR This presentation is available Google Earth files available for download –Grid and wetland data from presentation –Monitoring stations, point sources –Final EFDC grid information –NOAA bathymetry

57. Present Work Running water quality model now w/ new grid Still waiting to get BOD data from LCFR Program Finish assigning decay rates and redefining loads once additional BOD data are available Work on incorporating SOD data in a more detailed way Do additional model/data comparisons w/ DWQ special study data