District Surface Water Model (DSWM) Project Training Webinar

1. District Surface Water Model (DSWM) Project Training Webinar SWFWMD December 19, 2013

2. Agenda • Agenda • Presentation • Background • DSWM development and calibration • Select a watershed to go through • Results for all watersheds • HSPF • Background/Theory • Data • Model development steps • Interfaces • Run procedures • Recharge Rate Extraction • Hands-on Session

3. Objectives • To develop and calibrate an HSPF*-based numerical model(s) that simulates surface water flow and groundwater recharge in the Northern District Model (NDM) domain area and the entire District. DSWM – District-wide Surface Water Model. • To update the existing NDM (Version 3) with recharge and ET estimated by the surface water model. * HSPF – Hydrologic Simulation Program, Fortran

4. DSWM Development and Calibration

5. Model Development • Segmentation and Land Use • Meteorological Data • Other Input Data (springs, irrigation, etc.) • Characterize Land and Stream Segments • Observed Streamflow Data/Calibration Locations • Calibration

6. Land Segmentation • Basis for land segments is District’s “DrainageBasin” data derived from FDEP Basin-24 coverage • Segment size similar to previous models: INTB and IBC • Adjustments to boundaries to accommodate waterbody transition (lake vs river), tributary connections, and stream gage locations • Non-contributing segments were “disconnected” and assigned parameters that resulted in all rainfall inputs that don’t evaporate going to recharge

7. Land Use • Land Use • Based on 2004 Florida Land Use from SWFWMD, SRWMD, SJRWMD, and SFWMD • Used INTB categories and procedures • Categories: Forest, Grass/Pasture, Agriculture/Irrigated, Mining/Other, Urban, Wetland, Urban Impervious, Water • Aggregated to model categories using FLUCCS codes • Impervious category • Effective Impervious Area = directly connected impervious areas • EIA computed by percentages of FLUCCS categories • All impervious area combined into a single “Urban Impervious” category

8. Meteorological Data – Rainfall • Rainfall data is NEXRAD (i.e., radar-derived) data at a 2x2 km grid resolution and 15 minute interval • NEXRAD data provided by District • Rainfall inputs for PERLNDs and IMPLNDs in each model segment are area-weighted averages of the rainfall values of the pixels overlying the segment • Data are stored in WDM file • A pilot study on one watershed determined that the NEXRAD data were sufficiently similar to the gage-derived rainfall database used in the INTB model to support a calibrated model • Differences between NEXRAD and gage rainfall were observed

9. Meteorological Data – Potential Evapotranspiration (PET) • PET data are computed (Priestly-Taylor method) at the same 2x2 km grid as used by NEXRAD • PET data are 1-day totals; data are available for June1995 - December 2010 • PET data developed by USGS and obtained from USGS • PET inputs for PERLNDs and IMPLNDs in each model segment are area-weighted averages of the PET values of the pixels overlying the segment • Daily PET data were disaggregated to 1 hour time step using a seasonally varying distribution function based on the pattern of daylight at the latitude of the watershed; data stored in WDM file • The pilot study determined that the USGS GOES PET data were very similar to the gage-derived PET database used in the INTB model; differences had minimal impact on model results

10. Irrigation • Irrigation is applied to the Agriculture/Irrigated PERLND in each model segment • Amounts based on District’s monthly water use permit data for GW and surface water pumping • Amounts separated into Spray and Drip categories • Monthly totals disaggregated to daily using a “PET deficit” computed from the rainfall and PET data • Data are stored in WDM files • Daily Spray amount is applied as “rainfall” over three hours starting at 7 AM • Daily Drip amount is applied as “surface inflow” (not subject to interception) over six hours starting at 7 AM

11. Surface Water Pumping • Surface water pumping (diversions) computed from District’s monthly water use permit database • Monthly surface water pumping totals for all permits in a subwatershed are summed, disaggregated to a constant daily rate, and stored in a WDM file • Water is removed from the model reach in the subwatershed where pumping occurs

12. Springs • Flow from springs are added to the model reach in the subwatershed where the springs are located • Spring discharge timeseries obtained from USGS and WM Districts and from pre-existing models • Springs: • Crystal, Rainbow, Silver, Homosassa, Chassahowitzka, WeekiWachee, Wekiva River watershed springs, Gourdneck, Harris,

13. Observed Streamflow Data • Observed daily streamflow is used to compare with simulated flow during calibration • Calibration/comparison performed at 73 gage locations • Data obtained from District database, USGS, and SJRWMD • Data stored in WDM files

14. Data Used to Characterize Land Areas and Stream/Lake Reaches • DEM – land area slope, stream slope, stream channel • Soils – infiltration • Land use – segment watershed by landuse/cover • NHD – stream and lake locations, sizes, connectivity • Existing models – conveyance system connectivity, lake and stream configuration, stream cross sections, HSPF FTABLEs • USGS - stream cross sections and rating curves • Lake surveys – lake FTABLEs • Depth to Groundwater – infiltration, target ET

15. Calibration • Calibration followed the standard hierarchical methodology • Focusing first on the overall water balance using the LZSN (lower zone nominal storage), INFILT (infiltration index), DEEPFR (fraction of GW inflow that is lost to recharge), and major ET parameters (e.g., LZETP) • Maintain reasonable differences in land-use sensitive parameters within a watershed • Compare total actual ET with land-use specific target ET and adjust balance between ET and recharge as necessary • Adjust low flow/high flow distribution with INFILT, AGWRC (GW recession), and BASET (baseflow ET)

16. Calibration (continued) • Adjust storm shape using INFILT, UZSN (upper zone nominal storage), INTFW (interflow), and IRC (interflow recession) • Comparisons between observed and simulated used in calibration • Hydrographs • Cumulative flow graphs • Flow duration graphs • Annual runoff totals • Statistics (errors at various flow regimes, correlation coefficient, NS model fit efficiency)

17. Overview of DSWM Watersheds • Area separated into 12 major watersheds to make model input and output manageable and reduce simulation times • HAT – Hillsborough River, Alafia River, and other Tampa area watersheds • CRY – Crystal River, Pithlachascotee River, Anclote River, ChassahowitzkaRiver, Homosassa River, WeekiWachi • WIT – Withlacoochee River • WAC – Waccasassa River • OKL – Oklawaha River, including Orange Lake area

18. Watersheds (continued) • KIS – Kissimmee River • MAN - Manatee/Little Manatee • MSR - Myakka and Sarasota Bay area • PCH – Peace River and Charlotte Harbor area • WOK - Western Okeechobee • CAL - Caloosahatchee River • EXT – Extended area - Etonia/Rice Creeks, Lake George area, Wekiva River

19. Summary of DSWM Development Principal Inputs: NEXRAD 15-minute rainfall and daily computed PET dataset, 2004 Florida Land Use (seven categories – same method as INTB); Segmentation: average size = 44 sqmiles Irrigation Input:based on groundwater and surface water pumping data; same method as INTB Calibration: ~75 calibration locations ET Comparisons: within error bounds of target ET (+/- 10%) for much of the area Model Performance: overall "fair" calibration to daily streamflow, monthly average flows show best results

20. Watersheds and HSPF Models

21. North Domain Model Expanded into St Johns River watershed

22. Final Model Segmentation

23. Watersheds in Northern Region

24. Hillsborough-Alafia-Tampa Watershed

25. Crystal-Pithlachascotee and Withlacoochee Watersheds

26. Oklawaha Watershed

27. Extended Area Watersheds – Rice Creek, Etonia Creek, Lake George Area creeks, Wekiva River, and local drainage to St. Johns River

28. Northern Region Calibration Results - Observed Annual Flows (inches) and Simulated Error Terms

29. Northern Region Calibration Results - Statistics of Daily and Monthly Flow Rates

30. Examples Northern Watersheds

31. Withlacoochee River near Holder • Add

32. Withlacoochee River near Holder

33. Hillsborough River at Morris Bridge

34. Hillsborough River at Morris Bridge

35. Summary of Examples • Both examples are good statistically except for low flows, which are too high in Hillsborough and too low in Withlacoochee • Withlacoochee Basin was difficult to calibrate due to large surface storage and groundwater contributions • Dry years are over-simulated and wet years are under-simulated, generally • NEXRAD rainfall appears to be low in early years and higher than gage rainfall in later years

36. Watersheds in Southern Region

37. Manatee and Myakka-Sarasota Watersheds

38. Peace-Charlotte Harbor Watershed

39. Kissimmee Watershed

40. Western Okeechobee and Caloosahatchee Watersheds

41. Peace-Charlotte Harbor Watershed

42. Southern Region Calibration Results - Observed Annual Flows (inches) and Simulated Error Terms

43. Southern Region Calibration Results - Statistics of Daily and Monthly Flow Rates

44. Examples Southern Watersheds

45. Peace River at Arcadia

46. Peace River at Arcadia

47. Braden River near Lorraine (Manatee)

48. Braden River near Lorraine (Manatee)

49. Summary of examples • Peace River is good statistically except for low flows, especially in two dry years (2000 and 2006) • Braden River (Manatee tributary) was difficult to calibrate; possibly because watershed/reach storage is under estimated, since peaks are early • Braden River low flows are over-simulated

50. Sample – Little Manatee River near Wimauma