CalSim II

The Water Resource Integrated Modeling System (WRIMS model engine, or WRIMS) is a generalized water resources modeling system for evaluating operational alternatives for large, complex river basins. WRIMS integrates a simulation language for flexible operational criteria specification, a linear programming solver for efficient water allocation decisions, and graphics capabilities for ease of use. These combined capabilities provide a comprehensive and powerful modeling tool for water resource systems simulation. The latest available version is 1.2.4b.

CalSim is the model used to simulate California State Water Project (SWP)/Central Valley Project (CVP) operations. 

Together, WRIMS and CalSim replaced the Department of Water Resources' planning model of the State Water Project/Central Valley Project system, DWRSIM. Unlike DWRSIM, in which the engine and model were tightly coupled, the entire system and related operational criteria in CalSim, are specified as input to WRIMS and may be modified or replaced without requiring changes in WRIMS.

WRIMS and CalSim are products of joint development between DWR and Bureau of Reclamation.

CalSim Water Resources Simulation Model License

CALSIM is copyrighted by the State of California, Department of Water Resources. It is licensed under the GNU General Public License, version 3. This means it can be copied, distributed, and modified freely, but you may not restrict others in their ability to copy, distribute, and modify it. See the license below for more details.

GNU General Public License

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Contact Information

For general questions and comments, contact

Include a brief description (10 words or less) of the bug in the subject field of the email. In the message body include the WRIMS version number, operating system, and a detailed description of the bug and the situation in which it occurred.