California Central Valley Groundwater-Surface Water Simulation Model – Fine Grid (C2VSimFG)

(Released on June 6, 2025) Version 1.5 of the California Central Valley Groundwater-Surface Water Simulation Model – Fine Grid (C2VSimFG) is a major update to Version 1.01, which was released in April 2021. C2VSimFG is a numerical model developed by the California Department of Water Resources (DWR) to simulate the movement of water through the linked land surface, groundwater, and surface water flow systems of California’s Central Valley. The model is built using DWR’s Integrated Water Flow Model Version 2024 (IWFM-2024.2.1594). Version 1.5 includes updated monthly historical data for stream inflows, surface water diversions, precipitation, evapotranspiration, and land use from October 1973 through September 2021. It dynamically estimates crop water demands and determines how those demands are met through contributions from precipitation, soil moisture, and surface water diversions, calculating the groundwater pumping required to meet any remaining demand. The model simulates the historical response of the Central Valley’s water system to observed stresses and can also be used to evaluate responses to future conditions. DWR makes C2VSimFG Version 1.5 available as an optional tool for Groundwater Sustainable Agencies and other interested parties engaged in developing and implementing Groundwater Sustainability Plans under the Sustainable Groundwater Management Act.

Data files

Data title and descriptionAccess dataFile detailsLast updated

C2VSimFG v1.5 model package

This a a compressed zip file containing C2VSimFG version 1.5 model input files and selected model outputs.


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06/06/25

C2VSimFG v1.5 full documentation with appendices

The C2VSimFG v1.5 full documentation zip file includes the following pdf files: * (1) C2VSimFG v1.5 main report; * (2) Appendix A: C2VSimFG historical Central Valley Land Use by crops; * (3) Appendix B: Linear regressions between CIMIS ETo and PRISM ETo; * (4) Appendix C ET comparison of ITRC C2VSIMFGv1.5 and v1.01 for the year 2011; * (5) Appendix D ET comparison of ITRC C2VSIMFGv1.5 and v1.01 for the year 2014; * (6) Appendix E Stream Inflows for C2VSimFG; * (7) Appendix F Surface Diversion and Flow Bypass for C2VSimFG; * (8) Appendix G Subregion land & water use and groundwater budgets; * (9) Appendix H Groundwater Elevation Comparison; * (10) Appendix I Selected Streamflow Hydrograph.


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06/07/25

C2VSimFGv1.5 GIS Shapefiles

C2VSimFGv1.5 Arc GIS Shapefiles in a zip file.


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06/06/25

C2VSimFG v1.5 groundwater and stream observation dataset

Groundwater and stream observation dataset compiled for used in model calibration and validation.


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06/06/25

C2VSimFG v1.01 Model files (Superseded by Version 1.5)

The C2VSimFG v1.01 Model is available in a compressed zip format due to its size (4.59 GB)


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08/11/23

C2VSimFG v1.01 updated GIS shape files

Updated small watershed shape file for removed small watersheds (active = 0)


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08/11/23

C2VSimFG v1.0 model files (Superseded by V1.01)

C2VSimFG Version 1.0: The 1.0 version of the Fine Grid California Central Valley Groundwater-Surface Water Simulation Model (C2VSimFG Version 1.0 ) is a computer program that simulates water movement through the linked land surface, groundwater, and surface water flow systems in California’s Central Valley using the DWR-developed software, Integrated Water Flow Model Version 2015 (IWFM-2015). C2VSimFG Version 1.0 contains monthly historical stream inflows, surface water diversions, precipitation, evapotranspiration, and land use acreages from October 1973 through September 2015 (Data is available in the input files for 1922 through 2015). C2VSimFG Version 1.0 dynamically calculates crop water demands, allocates contributions from precipitation, soil moisture and surface water diversions, and calculates the groundwater pumping rates required to meet the remaining demand. It simulates the historical response of the Central Valley’s groundwater and surface water flow system to historical stresses and can also be used to simulate the response to projected stresses. DWR is providing C2VSimFG Version 1.0 to Groundwater Sustainable Agencies (GSAs) and other related entities as an optional tool that can be used to perform analysis during development and implementation of their Groundwater Sustainability Plans (GSPs).


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12/06/23

C2VSimFG v1.0 GIS files

GIS shape files for C2VSimFG v1.0


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12/06/23

C2VSimFG BETA2 Model Files (superseded by Version 1.0)

The C2VSimFG Beta Model is available in a compressed zip format due to its size (3.5 GB uncompressed). The contents of the zip file include the model executables, model input files, and selected outputs from running the model and calculating zbudgets. The input files and parameter files are all in text files. Outputs are in text files and summaries have been developed and are contained in excel files. Within the zip file, there are 7 folders. The folder titled Bin contains the executables. The folder titled Budget contains a batch file and input file for creating budgets after the simulation has been completed. The folder titled Excel contains excel summaries of outputs of the Budgets and ZBudgets. The folder titled Preprocessor contains the geometry information for the model nodes, elements, streams, and layers. The folder titled Results contains the outputs from the model simulation, budgets, and Zbudgets. The folder titled Simulation contains all of the data for initial and boundary conditions as well as aquifer parameters. In addition, Simulation settings and features as well as the batch files for simulating the model are provided here. The folder titled Z-Budget contains the input files and batch files for running the ZBudgets using the model simulation results.


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12/20/23

C2VSimFG BETA Model Files (superseded by Version BETA2) )

The C2VSimFG Beta Model is available in a compressed zip format due to its size (2.3 GB uncompressed). The contents of the zip file include the model executables, model input files, and selected outputs from running the model and calculating zbudgets. The input files and parameter files are all in text files. Outputs are in text files and summaries have been developed and are contained in excel files. Within the zip file, there are 7 folders. The folder titled Bin contains the executables. The folder titled Budget contains a batch file and input file for creating budgets after the simulation has been completed. The folder titled Excel contains excel summaries of outputs of the Budgets and ZBudgets. The folder titled Preprocessor contains the geometry information for the model nodes, elements, streams, and layers. The folder titled Results contains the outputs from the model simulation, budgets, and Zbudgets. The folder titled Simulation contains all of the data for initial and boundary conditions as well as aquifer parameters. In addition, Simulation settings and features as well as the batch files for simulating the model are provided here. The folder titled Z-Budget contains the input files and batch files for running the ZBudgets using the model simulation results.


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12/20/23

Supporting files

Data title and descriptionAccess dataFile detailsLast updated

C2VSimFG v1.5 main report

The C2VSimFG v1.5 main report without the appendices


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06/07/25

Road map to running C2Vsim


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12/06/23

C2VSimFG v1.01 Release Note

C2VSimFG v1.01 Release Note summarizes the key updates and corrections.


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08/11/23

C2VSimFG v1.0 DWR Report: California Central Valley Groundwater-Surface Water Simulation Model - Fine Grid (C2VSimFG) Development and Calibration Version 1.0


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12/06/23