1. San Luis Drain Shutoff Simulations and Link-Node Recalibration
Joel Herr and Katie van Werkhoven
Systech Water Resources, Inc.
San Joaquin River DO TMDL PI Meeting
May 15, 2008

2. Outline San Luis Drain Shutoff Forecast / Hindcast Model Validation
Link-Node Recalibration
Conclusion

3. Simulation Runs Forecast Hindcast Load shifting Do nothing forecast
Add flow and loading from off week to week before shutoff
No net load reduction, only shift
Do nothing forecast
Assume flow and loading trends continue
Hindcast
Actual event: use measured data
Do nothing
Use measured data except for continuous flow, load from Mud Slough

4. Load shifting SL Drain shutoff forecast vs Do nothing forecast
Forecast Results: EC
Load shifting SL Drain shutoff forecast vs Do nothing forecast

5. Forecast Results: Phytoplankton
Load shifting SL Drain shutoff forecast vs Do nothing forecast

6. Relative Error of Input Projections
Mud Slough
Salt Slough
Lander
Merced River
Tuolumne River
Stanislaus River
Flow 0%
+55%
+30%
-21%
12%
-22% EC
-15%
-14%
-13%
+2%
+29%
-10%
Phyto-plankton
+250%
-5%
+8%
+601%
+57%
+525%

7. Actual SL Drain shutoff event vs Do nothing hindcast
Hindcast Results: EC
Actual SL Drain shutoff event vs Do nothing hindcast

8. Hindcast Results: Phytoplankton
Actual SL Drain shutoff event vs Do nothing hindcast

9. Prediction of Flow at Vernalis

10. Prediction of EC at Vernalis

11. Phytoplankton at Vernalis

12. Response at Crows Landing

13. Response at Vernalis

14. Response at Brandt Bridge

15. D.O. at Rough & Ready Island
Effect on DO at RRI:
Was minimal: ~0.01 mg/l
Signal of decreased phytoplankton mostly dispersed by Brandt Bridge
Effect spread out over 2-3 weeks
What does this mean?
Load shifting signal does not transmit well to DWSC
Little effect for short-term loading reduction

16. What did we learn?
Reducing Mud Slough phytoplankton load may be effective at reducing phytoplankton at Vernalis & Old River
DWSC DO response is small, delayed, and diffused over longer time period

17. Outline San Luis Drain Shutoff Forecast / Hindcast Model Validation
Link-Node Recalibration
Conclusion

18. Validation: Flow at Vernalis

19. Validation: EC at Vernalis

20. Validation: Phytoplankton at Vernalis

21. Phytoplankton Sampling

22. What’s up with 2007? Flow simulation very accurate
Simulated EC ~20% less than observed
Simulated Phytoplankton much less than observed
Model error or data error?
Where are errors originating?

23. Data status for 2007 Meteorology: complete
Tributary inflows: mostly complete
Merced River has missing time periods
Los Banos Creek flow estimated
Less data for agricultural drains
Tributary water quality: complete
Diversions: 2007 flow data included for 1 of 4 ID’s; estimated for the rest

24. Possible Sources of Model Error
Newman Wasteway
DMC Recirculation occurred 8/15-9/12/2007
Salt Slough / Mud Slough / Los Banos Ck
Monitoring stations upstream of SJR
Phytoplankton growth may occur before entering the SJR
Unknown inputs not included in model

25. Location of EC Error EC is conservative:
Calculate mass error (simulated – observed load) at Crows Landing
Calculate mass error at Vernalis
EC error at Crows Landing accounts for 48% of error at Vernalis

26. Location of Phytoplankton Error
Fixed phytoplankton at Crows Landing: Simulation shows Vernalis is OK

27. Phytoplankton Growth

28. Model changes
Mud Slough, Salt Slough, Los Banos creek downstream of monitoring stations added to model domain
20-25% phytoplankton growth before reaching SJR
Newman Wasteway added to model domain, DMC recirculation of 2004 and 2007 simulated
Operational for limited time, dilution effect

29. Model Changes

30. Outline San Luis Drain Shutoff Forecast / Hindcast Model Validation
Link-Node Recalibration
Conclusion

31. Link-Node Recalibration Goals
Improve D.O. simulation from Old River to Channel Point, maintain calibration at Rough & Ready Island
Improve phytoplankton simulation, especially from Old River to Channel Point
Increase ammonia from Old River to Channel Point

32. Link-Node Recalibration Method
Recalibration attempted with global reaction rates (unsuccessful)
Link-Node code upgraded for reaction rates which vary by node
Reaction rates recalibrated in two sections: DWSC and elsewhere

33. Link-Node Recalibration
(Live demonstration of simulation results)

34. Brandt Bridge Phytoplankton
(live demonstration of Link-Node output)

35. Brandt Bridge Dissolved Oxygen

36. Garwood Bridge Phytoplankton

37. Garwood Bridge Dissolved Oxygen

38. Rough & Ready Dissolved Oxygen

39. What happens now?
San Joaquin River Model Interface (WARMF & Link-Node) will continue to be available for download
Updates will be available with new projects
Users can get technical support from Systech: