Sep 21, 2016 - The modeling testimony gave an overview of the models, tools and ... be used for comparative and not pred
Modeling Testimony in Brief September 21, 2016 The modeling testimony gave an overview of the models, tools and methodology used to analyze California WaterFix, and included various modeling scenarios, assumptions and results. Specifically, the models were used to evaluate projected changes in water supply, water quality and water levels that may affect legal users of water. It is important to note that while models are extremely useful, they are a planning tool that should be used for comparative and not predictive purposes, or to replicate historical conditions. Takeaways The models used for WaterFix were CalSim II (hydrology and system operations), DSM2-Hydro (Delta Hydrodynamics) and DSM2-QUAL (Delta water quality). CalSim II simulates operational scenarios of the State Water Project (SWP)/Central Valley Project (CVP) using a monthly time step DSM2 simulates Delta hydrodynamics and water quality and uses a 15-minute time step Modeling results compare WaterFix scenarios to the No Action Alternative (NAA) The modeling shows that under WaterFix, water quality would meet D-1641 objectives. Changes to SWP/CVP water deliveries based on the models: No substantial differences to CVP San Joaquin River exchange and Sacramento River settlement contractors, or south of Delta refuges No substantial differences to SWP Feather River Settlement contractors Maximum decreases in critical years were less than 1% Changes to SWP/CVP Delta diversions based on the models: Boundary scenarios result in substantial changes in diversions (from +1,200,000 AFY to -1,100,000 AFY) depending on north Delta diversion operational assumptions Range of proposed WaterFix operational scenarios - essentially no change compared to the NAA to a 10% increase over the NAA Changes in Delta water levels based on the models: The largest reduction in water levels was near the proposed north Delta diversion and only during high flow events During low flows, a maximum water level reduction of about 0.5 feet near the north Delta diversion, which only occurred for a short period during tidal cycles Locations far from the north Delta diversion show negligible reductions in water levels
