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

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

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

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

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

Relative Error of Input Projections Mud Slough Salt Slough SJR @ 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%

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

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

Prediction of Flow at Vernalis

Prediction of EC at Vernalis

Phytoplankton at Vernalis

Response at Crows Landing

Response at Vernalis

Response at Brandt Bridge

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

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

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

Validation: Flow at Vernalis

Validation: EC at Vernalis

Validation: Phytoplankton at Vernalis

Phytoplankton Sampling

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?

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

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

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

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

Phytoplankton Growth

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

Model Changes

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

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

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

Link-Node Recalibration (Live demonstration of simulation results)

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

Brandt Bridge Dissolved Oxygen

Garwood Bridge Phytoplankton

Garwood Bridge Dissolved Oxygen

Rough & Ready Dissolved Oxygen

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: joel@systechwater.com 925-355-1780