Sacramento and San Joaquin River Basins Comprehensive Study Technical Studies Documentation: Reservoir Operations Modeling – Existing Design Operations and Re-operation Analyses

In response to extensive flooding and damages experienced in 1997, the United States Congress authorized the U.S. Army Corps of Engineers, Sacramento District (USACE) to provide a comprehensive analysis of the Sacramento and San Joaquin river basin flood management systems and to partner with the State of California to develop master plans for flood damage reduction. The USACE and the State Reclamation Board of California are leading this Comprehensive Study to improve flood management and integrate ecosystem restoration in the Sacramento and San Joaquin river basins.

The authorization for the Comprehensive Study directed the development of hydrologic and hydraulic models for both river basins that will allow systematic evaluation. These models incorporate reservoir operations and flow along the major river systems to evaluate the performance of the flood management systems. The models can be used to assess the performance of the current systems or modified systems under a wide range of hydrologic conditions.

This report documents the work conducted for the Sacramento and San Joaquin River Basins Comprehensive Study to develop reservoir operation models, specifically Phase II – Model Refinement and Simulation of both existing operational conditions and evaluation of flood management alternatives. The main product components of this effort include: HEC-5 Reservoir Operation Models for the Sacramento and San Joaquin River basins, which will include headwater and major flood management reservoirs.

The first part of this document is limited to the use of reservoir models to identify and describe baseline conditions. It does not include the formulation or evaluation of flood management alternatives. The performance of modified flood management strategies is addressed within subsequent sections of this document. Future work will continue to use these models in the analysis of alternatives for reducing flood damages in California’s Central Valley.