Data and Tools

We have a long history of data collection, monitoring, and reporting. With the passage of the Sustainable Groundwater Management Act (SGMA), there is an increased need for local and state agencies and the public to easily access water data in order to make informed management decisions.

Data Tools and Reports Fact Sheet ( PDF) | (Revision Date: May 08, 2026) (Publish Date: Nov 12, 2025)

Quick reference guide to data, tools and guidance that help Groundwater Sustainability Agencies (GSAs) develop Groundwater Sustainability Plans (GSPs), and implement the requirements of the Sustainable Groundwater Management Act (SGMA).

Tags: Groundwater-Management

California Natural Resources Agency Open Data Platform

The CNRA Open Data Platform has been developed to provide data to State of California citizens, agencies, and interested stakeholders in a transparent and useful manner. The Open Data Platform supports the CNRA organizations’ and programs’ missions by providing an environment to publish and share useful data that can be effectively utilized by all.

DWR's SGMA Portal

DWR's SGMA Portal allows local agencies, groundwater sustainability agencies (GSAs), and watermasters to submit, modify, and view the information required by the Sustainable Groundwater Management Act (SGMA). It also enables you to view submitted information and provide comments, where applicable. You don't need a login for public access.

The Water Data Library

The Water Data Library contains hydrologic data (groundwater level data and some groundwater quality data) for over 35,000 wells in California. The data is collected by DWR Region Offices and dozens of local and federal cooperators.

California Statewide Groundwater Elevation Monitoring (CASGEM) Program

California Statewide Groundwater Elevation Monitoring (CASGEM) Program - In 2009, the Legislature passed SBX7 6, which establishes, for the first time in California, collaboration between local monitoring parties and DWR to collect groundwater elevations statewide and that this information be made available to the public.

California's Groundwater Live Website

California’s Groundwater Live website features the latest groundwater information, live statistics, and a series of interactive dashboards. Content is organized based on current conditions, groundwater levels, well infrastructure, land subsidence, and SGMA Reporting.

SGMA Data Viewer

The SGMA Data Viewer provides access to groundwater related datasets that are organized by the requirements of SGMA and the Groundwater Sustainability Plan (GSP) regulations for the purpose of supporting GSP development and implementation.

AEM Data Viewers

The Airborne Electromagnetic (AEM) Data Viewers are innovative tools that allow GSAs and stakeholders to view AEM datasets online. These GIS-based tools enable datasets to be visualized in a three-dimensional space, allowing users to zoom in, rotate, and explore the data from multiple angles.

California DWR Land Use Viewer

The CADWR Land Use Viewer allows you to easily view and download both statewide and existing county land use datasets. The application also enables you to view crop specific information and visualize land use change over time. Learn more about crop mapping at our Open Data website or view a SGMA Tech Talk webinar for a demo.

California DWR Well Completion Report Map Application

The Well Completion Report Map Application provides direct statewide access to copies of Well Completion Reports. Well Completion Reports contain information collected by drillers during the drilling and construction of water wells, including the location, dates of construction, planned use, depth of the well, subsurface geologic units encountered, well construction, and well yield.

Financial Assistance Mapping Tools

DWR’s Financial Assistance has developed three web-based mapping applications to assist local agencies and other interested parties in water management planning efforts. For additional information on Disadvantaged Communities, Economically Distressed Areas, and Water Management Planning see the Financial Assistance Mapping Tools page.

Modeling Code

DWR’s Modeling Support Branch of the Bay-Delta Office provides ongoing support for the Integrated Water Flow Model (IWFM) code. IWFM is a water resources management and planning model that simulates groundwater, surface water, stream-groundwater interaction, and other components of the hydrologic system.

Modeling Applications

California Central Valley Groundwater-Surface Water Simulation Model (C2VSim)

C2VSim is an integrated numerical model that simulates water movement through the linked land surface, groundwater and surface water flow systems in California's Central Valley using the IWFM modeling platform.

Current Release of the Fine-Grid Version

Download at Open Data

Sacramento Valley Groundwater-Surface Water Simulation Model (SVSim)

SVSim is a new model of the Sacramento Valley using the IWFM code and based on the C2VSim-Fine Grid dataset. This model is being developed to support more detailed analysis of streamflow depletion due to groundwater substitution transfers as well as support the implementation of SGMA. SVSim will have an updated representation of the hydrogeologic conceptual model and aquifer parameters based on an extensive lithologic texture analysis. It will also have a more refined (smaller) horizontal grid along major waterways and more discretized vertical layering. A beta version of SVSim was posted on April 30, 2020. The calibrated SVSim Version 1.0 model including complete documentation is now available.

SVSim Technical Memos:

SVSim TM-1A: Modeling Approach for C2VSim Enhancement
SVSim TM-1B: Development of Hydrogeologic Conceptual Model and Aquifer Parameters
SVSim TM-2: Model Grid Development
SVSim TM-3: Model Input Data Development
SVSim TM-4: Calibration and Sensitivity Analysis

SVSim Version 1.0 and the Beta Release, TM's, Fact Sheet, and the Sacramento Valley Texture Data can be accessed and commented on at the links below:

Download at Open Data

DWR is providing data, tools, and guidance to assist GSAs with incorporating climate change into their GSPs. This effort leverages previous work done by DWR for the California Water Commission Water Storage Investment Program (WSIP). The intent is to provide GSAs with a possible method to include climate change into their projected water budget calculations, especially if no local climate change analysis has been done before.

Screen shot of Open Data Platform CNRA Open Data Platform - SGMA Climate Change Resources

The climate change resources are available through the CNRA Open Data Platform. These resources include the data, tools, and guidance in a single location and the access to download the desktop tools. These desktop tools are designed to assist users of the climate change data and processing the climate change projections to integrated hydrologic models.

CNRA Open Data Platform Climate Change Toolbox Climate Change Tools

The ArcGIS tools are developed to assist users in developing projected precipitation and evapotranspiration input files for models.

ArcGIS Climate Change Toolbox for MODFLOW

ArcGIS Climate Change Toolbox for IWFM

The Second Order Correction Tool is to assist users in correcting streamflow timing under projected conditions.

Resource Guide

The Resource Guide gives GSAs and other stakeholders a high-level overview of the climate change resources including datasets provided by DWR, tools for working with the DWR-provided datasets, and guidance for using DWR-provided data and tools in developing GSPs. The datasets and methods can provide technical assistance to GSAs for developing projected water budgets.

Guidance for Climate Change Data Use During Sustainability Plan Development

The objective of this Guidance Document is to provide Groundwater Sustainability Agencies (GSAs) and other stakeholders with information regarding climate change datasets and related tools provided by the California Department of Water Resources (DWR) for use in developing Groundwater Sustainability Plans (GSPs). The datasets and methods are provided as technical assistance to GSAs to develop projected water budgets.

Climate Change Fact Sheet

The Climate Change Fact Sheet describes the Sustainable Groundwater Management Program (SGMP) Technical Assistance Climate Change Analysis data sources and the application of climate change data for Sustainable Groundwater Management Act (SGMA) implementation.

Statewide Reports

California's Groundwater Bulletin 118

California’s Groundwater: Bulletin 118 Updates (CalGW Updates) are the State’s official publications on the occurrence and nature of groundwater in California. CalGW Updates consist of a summary Highlights (English, Spanish), a detailed Statewide Report, and a series of Appendices.

Semi-Annual Conditions Updates

Semi-Annual Conditions Updates are more frequent supplements to the comprehensive 5-year CalGW Updates and provide additional perspective on near-real-time data availability through CalGW Live. These Updates are published in March and October each year and include key findings, groundwater level conditions, subsidence monitoring, statewide well infrastructure changes, groundwater extraction and change in storage data from groundwater sustainability plans, and discussions of current events.

California Water Plan

A new California Water Plan is produced every five years by the Department of Water Resources (DWR). The 2028 Water Plan will guide water resource decisions, support implementation, and help California plan for a hotter and more unpredictable future.

Water Available for Replenishment - WAFR

Water Available for Replenishment - Final Report | (Publish Date: Apr 12, 2018) Version: Final

A critical element of sustainable groundwater management is the replenishment of groundwater basins. SGMA directs the California Department of Water Resources (DWR) to provide assistance to local agencies in estimating the amount of water available for groundwater replenishment. The act directs DWR to prepare a report “that presents the department’s best estimate, based on available information, of water available for replenishment of groundwater in the state” (California Water Code Section 10729(c)). This report satisfies that statutory requirement.

Appendix A for Water Available for Replenishment - Information and Estimates ( PDF) | (Publish Date: Apr 12, 2018)

As part of development of the WAFR Report, a series of technical analyses were conducted to provide DWR’s estimates of water available for replenishment in the state, based on available information. An important step in conducting these analyses was to establish existing information and tools.

Tags: Groundwater-Management, Sustainable-Groundwater-Management-Act

Appendix B for Water Available for Replenishment - SWP and CVP Reliability and Availability ( PDF) | (Publish Date: Apr 12, 2018)

This appendix provides historical information and context for the SWP and CVP as background to estimates of the current reliability of surface water deliveries for both projects. This appendix also includes a summary of results from surface water project investigations that quantify the additional surface water supplies that may be developed by enhancing California’s water infrastructure. This appendix also includes information on how water supplies, particularly inflow to major reservoirs, may be affected by climate change.

Tags: Groundwater-Management, Sustainable-Groundwater-Management-Act

Appendix C for Water Available for Replenishment - Method Guidance ( PDF) | (Publish Date: Apr 12, 2018)

The guidance to assess and plan water available projects or management actions from each water available method can be found in Appendix C. These water available methods include surface water, including stormwater; water conservation; recycled water; desalination; and water transfers.

Tags: Groundwater-Management, Sustainable-Groundwater-Management-Act

Appendix D for Water Available for Replenishment - Methods of Replenishment Guidance ( PDF) | (Publish Date: Apr 12, 2018)

Managed replenishment methods can be generally divided into two main categories: direct replenishment and indirect or in-lieu replenishment. These methods affect different components of a groundwater budget. The considerations described in this appendix will be the responsibility of the GSAs, including water agencies and their consultants, who can best evaluate the optimal civil and hydrogeological aspects of recharge projects for their GSAs.

Tags: Groundwater-Management, Sustainable-Groundwater-Management-Act

White Paper - Water Available for Replenishment | (Publish Date: Apr 01, 2016)

This white paper first defines and describes “water available for replenishment” by separating the concept into two constituent parts (Section 2): (1) water available, and (2) for replenishment of groundwater. An implementing entity (such as a GSA) would likely need to develop a project in two parts — first, to identify the timing and amount of water available, and second, to determine the location and logistics for groundwater replenishment.

Handbook for Water Budget Development

Draft Handbook for Water Budget Development

Decorative image of the Water Budget handbook

The California Department of Water Resources (DWR) has released a draft Handbook for Water Budget Development: With or Without Models, a single-volume, technical reference that systematically presents existing information on various methods and data sources for developing water budgets. The Water Budget Handbook can help in the development of water budgets for any geographic area and time period, and uses modeling and non-modeling approaches.

Proposition 68 Technical Support Projects

The Department of Water Resources (DWR) is leading eight Proposition 68-funded projects managed through the Sustainable Groundwater Management Program. These projects provide groundwater sustainability agencies, related stakeholders, and the public with regional and statewide data, tools, and analysis aligned with the technical requirements of the groundwater sustainability plan (GSP) regulations and the Sustainable Groundwater Management Act (SGMA).

The projects can help GSAs successfully develop and implement GSPs. These activities also allow DWR to adequately evaluate GSPs within the statutory deadlines of SGMA. The projects will provide publicly available data to facilitate additional water management activities including groundwater recharge and conjunctive use which will contribute to drought resilience and regional sustainability. The data collection, tool development, and analysis efforts will be focused in the critically overdrafted groundwater basins and in high- and medium-priority basins across the state. Below are fact sheets for each of the projects:

Proposition 68-Funded Project Fact Sheets:

Conduct Airborne Electromagnetic Surveys - Published 2020
Improve Groundwater Elevation and Quality Monitoring Network - Published 2019
Statewide Land Use Data Collection - Published 2019
Improve Subsidence Monitoring Network - Published 2019
Install and Maintain Stream Gauges - Published 2019
Maintain and Enhance Statewide Well Completion Reports - Published 2019
Manage and Report Sustainable Groundwater Information - Published 2019 (Includes planned timeline for projects)
Enhance and Maintain DWR’s Modeling Tools - Published 2019

For information on the Sustainable Groundwater Management Grant Program, please visit the Sustainable Groundwater Management Grant Program webpage.

DWR is providing the Sustainable Groundwater Management Act (SGMA) Water Year Type Dataset to assist GSAs with their GSP water budget development, as stated in the GSP Regulations (23 CCR Section 354.18). The use of the Dataset is optional as GSAs may utilize data of comparable quality.

SGMA Water Year Type Dataset

The SGMA Water Year Type Dataset and accompanying reports are available through CNRA Open Data Platform.

The dataset provides the water year type classifications for 98 HUC-8 watersheds in California. The reports describe the background for implementing water year types, process for developing the dataset, and a discussion on dataset updates.

Note: The SGMA Water Year Type Dataset has been developed to assist GSAs in the development and implementation of their GSPs, should they choose not to develop their own water year type based on available data.

Resources

DWR and other agencies are developing guidelines, tools, best management practices, and regulations to assist local agencies with their sustainable groundwater management planning efforts. Statewide and regional foundations, academic institutions, nonprofit organizations, and groups within and outside of California have prepared reference documents, presentations, case studies, and conceptual models intended to help local agencies make informed decisions about sustainable groundwater management. DWR makes these resources available to the public through its Sustainable Groundwater Management website; however, does so for the convenience of the user and is not responsible for its content.

Data and Tools

Modeling Code

Modeling Applications

California Central Valley Groundwater-Surface Water Simulation Model (C2VSim)

Current Release of the Fine-Grid Version

Sacramento Valley Groundwater-Surface Water Simulation Model (SVSim)

Statewide Reports

Water Available for Replenishment - WAFR

Handbook for Water Budget Development

Draft Handbook for Water Budget Development

Proposition 68 Technical Support Projects

SGMA Water Year Type Dataset

Resources

Additional DWR Resources

State & Federal Resources

External & Local Agency Resources

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