1. 1 Guadalupe Watershed Model Year 2 update Presentation to SPLWG May 27, 2009 Michelle Lent, John Oram, Lester McKee Item #7

2. 2 Basic Objective (revised): –To understand the source, release, and transport of suspended sediment, Hg and PCBs from a large, mixed land use watershed to San Francisco Bay Timeline: –Year 1 (2008): Hydrologic model –Year 2 (2009): Sediment and contaminants model Details: –Establish model input and calibration parameters to assist in developing other local watershed models –Improve accuracy of mercury and PCB load calculations –Addresses STLS Q1 (Impairment), Q2 (loads), Q3 (Trends), Q4 (Support for management actions) Modeling Strategy Q3 (Small tributary loads) Item #7

3. 3 Re-cap of last time Item #7 Model Overview & Set-up Software & data sets used Delineation & segmentation Model Calibration/Validation Split data into two sets (2000-05, 2006-07) Summary of Model Performance Captures general watershed hydrology & storm events Needs improvement for –Annual flow volume and base flow –Storm event peak flow and timing Model Improvement Plan Extend calibration period Add urban irrigation Revise imperviousness estimates Re-evaluate meteorological and calibration segmentation Suggestion from Workgroup Shift to spatial calibration/validation split -Calibrate upstream, validate downstream

4. 4 Canoas Creek Guadalupe Creek Los Gatos Creek Revised calibration & validation sites: Item #7 Upper Guadalupe River Ross Creek Lower Guadalupe River

5. 5 Extended simulation period Item #7

6. 6 Added urban irrigation Item #7

7. 7 Revised imperviousness estimates E.I.A. = 0.15*(T.I.A.) 1.14 (Alley and Veenhuis, 1983) Item #7

8. 8 Adjusted meteorological segmentation Item #7

9. 9 Re-evaluated calibration parameters & model parameterization Item #7 7 model segments 12 model segments

10. 10 Example result of model revisions Ross Creek flow with Vasona & Alamitos precipitation Item #7

11. 11 Compare model versions - Annual flow volumes for Guadalupe River Item #7 Water Year Prec (in) Obs. Flow Volume (10 6 cf) Sim. Flow Volume (10 6 cf) % Diff. from Obs. Flow Volume RatingSim. Flow Volume (10 6 cf) % Diff. from Obs. Flow Volume Rating 200317.62,1482,042-4.9% Very good 2,3429.0% Very good 200413.21,8741,442-23.1%Fair1,828-2.5% Very good 200520.52,5902,431-6.6% Very good 3,04017.4%Fair 200616.34,4744,371-2.3% Very good 5,04012.7%Good 20077.21,260870-30.9%Poor1,027-18.5%Fair Old version (v1)New version (v2)

12. 12 Compare model versions - Observed versus simulated daily flow for Guadalupe River Item #7 Old version (v1): WY 2003-2007 New version (v2): WY 1995-2007

13. 13 Compare model versions - Hourly flow for Guadalupe River Item #7

14. 14 Sediment model development: Data needs for parameterization & calibration Target sediment loading rates Item #7 NaturalAgricultural Low Density Urban High Density Urban Industrial 722,4614509961,836 Sediment production rates estimated for land use classes (tonnes/km 2 /yr) D.R. = 0.418*Area -0.135 - 0.127 Apply sediment delivery ratio edge of stream inputs Particle Size Distribution Soil Texture mapSoil Texture % clay/silt/sand Particle size distribution map Fractionation ratio

15. 15 Next time, calibrated SSC… Item #7

16. 16 Next Steps Calibrate sediment portion of model Extend model to Hg and PCBs Calibrate contaminant portion of model Deliverable Draft report by November SPLWG meeting Item #7