Delta Simulation Models (DSM1 & DSM2)
The DWRDSM2 model uses a four-point implicit solution scheme developed by the USGS and updated by the DWR Delta Modeling Section to solve the 1D Saint-Venant equations. The advection-dispersion equation is solved in the lagrangian reference frame using the Branched Lagrangian Transport Model developed by Harvey Jobson of the USGS. The model was extensively calibrated by an interagency team in 2000. The calibration relies on extensive measurement of Delta and Suisun Marsh bathymetry between 1998 and 2000. The tidal boundary is supplied at Carquinez Strait. The DWRDSM2 modeling suite also includes a Particle Tracking Model (PTM) that is capable of tracking individual particles based on deterministic longitudinal velocity and stochastic motions based on empirical mixing relationships. The Section uses the DSM2 model unless downstream boundary or Suisun Marsh managed wetland operations affect the solution.
The DWRDSM1 (Suisun Marsh version) is a variant of the Fischer Delta Model. The model computes tidal currents and water levels by solving the one-dimensional Saint-Venant equations using explicit finite differences and the method of characteristics. The model computes advection and dispersion of solutes in the lagrangian reference frame. The model was extensively calibrated in 1997 at the request of the CALFED Bay-Delta program. The model is based on a grid of the entire San Francisco Bay-Delta system including a downstream tide boundary at the Golden Gate and explicit treatment of Suisun Marsh managed wetlands. The section uses this model whenever managed wetland operation is important, or when the solution would impact water levels at Carquinez Strait.
In November 1996, the CALFED Bay-Delta Program asked DWR Suisun Marsh Planning to re-calibrate the DWR Delta Simulation Model Suisun Marsh Version model (DSM1) in response to concerns that the model was not adequately calibrated with flow data.
The Section maintains the DSM2 Cross-Section Development Program (CSDP), which is a tool for pre-processing bathymetry data for use with DSM2-Hydro. The Section develops tools for post-processing and presentation of model results, such as the DWR Operations Control Office