CalSim 3

CalSim 3 is a new and improved water resources planning model, jointly developed by the California Department of Water Resources (DWR) and the Mid-Pacific Region of the U.S. Bureau of Reclamation (Reclamation), to simulate operations of the State Water Project (SWP) and the Central Valley Project (CVP) and much of the water resources infrastructure in the Central Valley of California and the Sacramento-San Joaquin Delta region. It is the next generation of the CalSim-II model which has been used in various Central Valley water resources planning studies since its release in 2002. 

Major improvements and enhancements in CalSim 3.0 include:

  • Finer model spatial resolution
  • Better water supply and demand estimation
  • Improved groundwater representation and simulation
  • Enhanced model validation
  • Extended model spatial and temporal domain
  • Advanced model engine (WRIMS 2.0)
  • Thorough model documentation
  • Model supporting tools

Model Downloads

Support Tools

  • To view input and output dss files, please download HEC-DSSVue.
  • To exchange time series data between dss and Excel files, please download HEC-DSS Excel Data Exchange Add-In.
  • CalSim is an application of WRIMS. CalSim 3.0 can be viewed and run with the WRIMS GUI. More information can be found at WRIMS.
  • CalSim 3.0 is written in the WRESL and WRESL+ language. 

Contact Information


The purpose of this hands-on workshop is to help attendees learn how to prepare and modify selected model input data, make changes to the model hydrology implementation, run the model, and analyze model output.