cbec has developed and applied a variety of hydrodynamic and water temperature models for the American River, Lake Natoma and Folsom Reservoir.

The project has entailed bathymetric surveys, temperature and stage monitoring, as well as numerical model development, calibration, validation and application. The goal of the effort is to better understand how water resource management affects water temperature in the lower American River (LAR), in order to improve the condition of aquatic resources, particularly fall-run Chinook salmon and steelhead.

Physical Monitoring – Physical monitoring including stage and water temperature gaging, and bathymetric surveys were conducted to inform model development calibration and validation. cbec has deployed and continues to maintain 14 temperature loggers and 4 stage loggers along the LAR.  cbec has also undertaken bathymetric surveys for the entire 23 mile LAR and the 7 mile reach between Folsom and Nimbus Dams using a boat-mounted fathometer connected to RTK GPS.

Temperature Modeling – cbec has developed and applied several water temperature models for the riverine and reservoir components of the system.  A one-dimensional hydrodynamic and temperature model of the LAR was developed using HEC-RAS.  At the initiation of the project, this effort was the largest beta application of the newly developed temperature module of HEC-RAS. In addition we apply two-dimensional CEQUAL-W2 models of Folsom Reservoir and Lake Natoma in order to accurately simulate the temperature of water released to the LAR under various water resource management alternatives.

The suite of modeling tools have been applied to evaluate potential impacts in a real-time basis for current conditions and the potential benefits from modification of the temperature control device at Folsom Dam.  These tools have also helped evaluate conditions for various management alternatives for an 82-year planning period as simulated with the CALSIM water supply optimization model.  This effort has required the development of disaggregation techniques to post-process monthly CALSIM model outputs into sub-daily time series for use as boundary conditions for the HEC-RAS and CEQUAL-W2 models.