(Webpage Under Development)

The Department of Water Resources (DWR) provides Technical Support Services (TSS) to assist Groundwater Sustainability Agencies (GSAs) with the implementation of their Groundwater Sustainability Plans (GSPs) and other local entities to better understand groundwater conditions. These services support data collection, groundwater monitoring, and improved understanding of groundwater conditions to help advance sustainable groundwater management efforts across California.

Through the TSS program, DWR has partnered with GSAs and other entities on projects across the state to drill and construct groundwater monitoring wells, install groundwater level recording and telemetry equipment, perform downhole camera and geophysical surveys, and collect and analyze groundwater for general chemistry. The data and reports generated from these efforts are publicly available to support ongoing groundwater management and planning.

Additional information can be found on the Assistance and Engagement webpage.

Summary of Completed TSS Projects

To date, DWR has completed TSS projects in 35 groundwater subbasins, constructing 234 monitoring wells at 92 sites statewide. Each of these wells have been assigned a State Well Number (SWN), have had a Well Completion Report (WCR) submitted to DWRs Online System for Well Completion Reports (OSWCR), and have been registered either through the California Statewide Groundwater Elevation Monitoring (CASGEM) Online System or the Sustainable Groundwater Management Act (SGMA) Portal’s Monitoring Network Module (MNM).

Groundwater level data from these wells are collected by the GSA or DWR and submitted to CASGEM and/or the MNM. These data can be viewed on the Water Data Library (WDL).

WCRs for these wells can be found using the Well Completion Report Map Application.

A summary table of completed TSS wells including their associated well name(s), site code(s), SWN(s), and WCR number(s), can be viewed and/or downloaded here: DWR Completed TSS Wells

An interactive GIS map containing a feature set of all completed TSS wells can be accessed here: GIS Map of Completed TSS Wells

The individual TSS well locations, associated borehole lithologic information, and groundwater level data can be viewed on the SGMA Data Viewer by:

1. Checking the “DWR TSS Wells” box under the “Groundwater Levels” tab on the left side of the screen.

2. Clicking on any one of the well location symbols that appear on the interactive map.

3. Clicking on one of the associated Site Code numbers that appear in the results table.

Completed TSS Projects by Groundwater Subbasin

Below is a list of subbasins in which TSS projects have been completed. These projects are organized by DWR Region (Northern Region, North Central Region, South Central Region, and Southern Region). Each subbasin listed below has one or more completed TSS project. As more TSS projects are completed, they will be added to this list.

All completed TSS projects have several associated documents and datasets, including a Well Installation Summary Report, TSS Agreement between DWR and the GSA, CEQA Notice of Exemption (NOE), Land Use or License Agreement, Local Drilling Permit, Composite Lithologic Log, Survey Report, and a Water Quality Analytical Report. Some projects also include downhole geophysical logs. These data and reports can be accessed by clicking on the subbasin below in which the project is located.

Northern Region

Antelope Subbasin

Big Valley Subbasin

Butte Valley Subbasin

Colusa Subbasin

Corning Subbasin

Enterprise Subbasin

Red Bluff Subbasin

Shasta Valley Subbasin

Sierra Valley Subbasin

Wyandotte Creek Subbasin

North Central Region

Cosumnes Subbasin

Eastern San Joaquin Subbasin

North Yuba Subbasin

Petaluma Valley Subbasin

Santa Rosa Plain Subbasin

Solano Subbasin

Sonoma Valley Subbasin

South Yuba Subbasin

Tracy Subbasin

Ukiah Valley Subbasin

Yolo Subbasin

South Central Region

Delta Mendota Subbasin

Kaweah Subbasin

Kern County Subbasin

Kings Subbasin

Paso Robles Area Subbasin

Tule Subbasin

Turlock Subbasin

Southern Region

Borrego Springs Subbasin

Cuyama Valley Subbasin

Indian Wells Subbasin

Indio Subbasin

Mound Subbasin

Oxnard Plain Subbasin

Pleasant Valley Subbasin

Non-editable view of DWR water rights tracking database.Wrangled, cleaned, and uploaded 4/12/2022 LM, WW, TV, JE.

DWR has a long history of studying and characterizing California’s groundwater aquifers as a part of California’s Groundwater (Bulletin 118). California's Groundwater Basin Characterization Program provides the latest data and information about California’s groundwater basins to help local communities better understand their aquifer systems and support local and statewide groundwater management.

Under the Basin Characterization Program, new and existing data (AEM, lithology logs, geophysical logs, etc.) are integrated to create continuous maps and three-dimensional models. To support this effort, new data analysis tools have been developed to create texture models, hydrostratigraphic models, and aquifer flow parameters. Data collection efforts have been expanded to include advanced geologic, hydrogeologic, and geophysical data collection and data digitization and quality control efforts will continue. To continue to support data access and data equity, the Basin Characterization Program has developed new online, GIS-based, visualization tools to serve as a central hub for accessing and exploring groundwater related data in California.

Additional information can be found on the Basin Characterization Program webpage.

DWR's Evaluation of Groundwater Resources

Maps and Models

DWR is undertaking local, regional, and statewide investigations to evaluate California's groundwater resources and develop state-stewarded maps and models. New and existing data have been combined and integrated using the analysis tools described below to develop maps and models that describe grain size, the hydrostratigraphic properties, and hydrogeologic conceptual properties of California’s aquifers. These maps and models help groundwater managers understand how groundwater is stored and moves within the aquifer. The models will be state-stewarded, meaning that they will be regularly updated, as new data becomes available, to ensure that up-to-date information is used for groundwater management activities. The first iterations of the following maps and models will be published as they are developed:

• Texture Models
• Hydrostratigraphic Models
• Aquifer Recharge Potential Maps
• Extent of Important Aquifer Units
• Depth to Basement
• Depth to Freshwater

Click on the link below for each local, regional, or statewide investigation to find the following datasets.

Local Investigations

• Madera & North Kings: AEM data collection, lithology log digitization, texture model development, aquifer recharge potential mapping analysis.
• Pajaro: AEM and tTEM data collection
• Western San Joaquin Valley: AEM data collection, lithology and geophysical log data digitization, texture model development.
• Prospect Island: AEM data collection, FloaTEM data collection test.

Regional Investigations

• Sacramento Valley: AEM data collection, texture model development, aquifer recharge potential mapping analysis.
• Four County Area of San Joaquin Valley (Madera, Fresno, Kings, and Tulare counties) : AEM data collection, texture model development, hydrogeologic conceptual model development, clay delineation, subsidence potential and mitigation, and aquifer recharge potential mapping analysis.
• San Joaquin Valley

Statewide Investigations

• Statewide AEM Surveys: AEM data collection, geophysical and lithology log data digitization.

Data Collection & Compilation

As a part of the Basin Characterization Program, advanced geologic, hydrogeologic, and geophysical data will be collected to improve our understanding of groundwater basins. Data collected under Basin Characterization are collected at a local, regional, or statewide scale depending on the scope of the study. Advanced data collection methods include:

• Airborne electromagnetics (AEM)
• All-terrain vehicle towed electromagnetics (tTEM)
• Watercraft towed electromagnetics (FloaTEM)
• Geophysical borehole logging

Digitized Existing Lithology and Geophysical Logs

Lithology and geophysical logging data have been digitized to support the Statewide AEM Survey Project and will continue to be digitized to support Basin Characterization efforts. All digitized lithology logs with Well Completion Report IDs will be imported back into the OSWCR database. Digitized lithology and geophysical logging can be found under the following resource:

• Digitized Lithology and Geophysical Logs.

Analysis Tools and Process Documents

To develop the state-stewarded maps and models outlined above, new tools and process documents have been created to integrate and analyze a wide range of data, including geologic, geophysical, and hydrogeologic information. By combining and assessing various datasets, these tools help create a more complete picture of California's groundwater basins. All tools, along with guidance documents, are made publicly available for local groundwater managers to use to support development of maps and models at a local scale. All tools and guidance will be updated as revisions to tools and process documents are made.

Data Analysis Tools

• Data2Texture: Data2Texture is an advanced spatial data interpolation tool for estimating the distribution of sediment textures from airborne electromagnetic data and lithology logs to create a 3D texture model

• Data2HSM - Smart Interpretation: Data2HSM via Smart Interpretation (SI) is a semi-automatic Python tool for delineating continuous hydrogeologic surfaces from airborne electromagnetic data products.

• Data2HSM - Gaussian Mixture Model: The Data2HSM via Gaussian Mixture Model tool ingests the AEM data and groups the data into a user-specified number of clusters that are interpreted as stratigraphic units in the hydrostratigraphic model (HSM)

• Data2HSM - Geological Pseudolabel Deep Neural Network: The GeoPDNN (Geological Pseudolabel Deep Neural Network) is a semi-supervised machine learning tool that integrates lithologic well logs and AEM data into plausible stratigraphic surfaces.

• Texture2Par V2: Texture2Par V2 is a groundwater model pre-processor and parameterization utility developed to work with the IWFM and MODFLOW families of hydrologic simulation code.

Process Documents

• Aquifer Recharge Potential Mapping: The Aquifer Recharge Potential (ARP) Mapping Process Document provides a framework for identifying locations that have relatively higher potential for managed aquifer recharge.

Data Visualization

Data access equity is a priority for the Basin Characterization Program. To ensure data access equity, the Basin Characterization Program has developed applications and tools to allow data to be visualized without needing access to expensive data visualization software. This list below provides links and descriptions for the Basin Characterization's suite of data viewers.

SGMA Data Viewer: Basin Characterization tab: Provides maps, depth slices, and profiles of Basin Characterization maps, models, and datasets, including the following:

• Aquifer Recharge Potential Maps
• Subsurface Texture Model Depth Slices
• Statewide AEM Survey Texture Depth Slices
• Lithology Log Location Maps
• Geophysical Logs Location Maps
• Statewide AEM Survey Profile Images

3D AEM Data Viewer: Displays the Statewide AEM Survey electrical resistivity and coarse fraction data,

DWR has a long history of studying and characterizing California’s groundwater aquifers as a part of California’s Groundwater (Bulletin 118). California's Groundwater Basin Characterization Program provides the latest data and information about California’s groundwater basins to help local communities better understand their aquifer systems and support local and statewide groundwater management. Under the Basin Characterization Program, new and existing data (AEM, lithology logs, geophysical logs, etc.) are integrated to create continuous maps and three-dimensional models. To support this effort, new data analysis tools have been developed to create texture models, hydrostratigraphic models, and aquifer flow parameters. Data collection efforts have been expanded to include advanced geologic, hydrogeologic, and geophysical data collection and data digitization and quality control efforts will continue. To continue to support data access and data equity, the Basin Characterization Program has developed new online, GIS-based, visualization tools to serve as a central hub for accessing and exploring groundwater related data in California. Additional information can be found on the Basin Characterization Program webpage. DWR's Evaluation of Groundwater Resources Maps and Models DWR is undertaking local, regional, and statewide investigations to evaluate California's groundwater resources and develop state-stewarded maps and models. New and existing data have been combined and integrated using the analysis tools described below to develop maps and models that describe grain size, the hydrostratigraphic properties, and hydrogeologic conceptual properties of California’s aquifers. These maps and models help groundwater managers understand how groundwater is stored and moves within the aquifer. The models will be state-stewarded, meaning that they will be regularly updated, as new data becomes available, to ensure that up-to-date information is used for groundwater management activities. The first iterations of the following maps and models will be published as they are developed: Texture Models Hydrostratigraphic Models Aquifer Recharge Potential Maps Extent of Important Aquifer Units Depth to Basement Depth to Freshwater Click on the link below for each local, regional, or statewide investigation to find the following datasets. Local Investigations Madera & North Kings: AEM data collection, lithology log digitization, texture model development, aquifer recharge potential mapping analysis. Pajaro: AEM and tTEM data collection Western San Joaquin Valley: AEM data collection, lithology and geophysical log data digitization, texture model development. Prospect Island: AEM data collection, FloaTEM data collection test. Regional Investigations Sacramento Valley: AEM data collection, texture model development, aquifer recharge potential mapping analysis. Four County Area of San Joaquin Valley (Madera, Fresno, Kings, and Tulare) San Joaquin Valley Statewide Investigations Statewide AEM Surveys: AEM data collection, geophysical and lithology log data digitization. Data Collection & Compilation As a part of the Basin Characterization Program, advanced geologic, hydrogeologic, and geophysical data will be collected to improve our understanding of groundwater basins. Data collected under Basin Characterization are collected at a local, regional, or statewide scale depending on the scope of the study. Advanced data collection methods include: Airborne electromagnetics (AEM) All-terrain vehicle towed electromagnetics (tTEM) Watercraft towed electromagnetics (FloaTEM) Geophysical borehole logging Digitized Existing Lithology and Geophysical Logs Lithology and geophysical logging data have been digitized to support the Statewide AEM Survey Project and will continue to be digitized to support Basin Characterization efforts. All digitized lithology logs with Well Completion Report IDs will be imported back into the OSWCR database. Digitized lithology and geophysical logging can be found under the following resource: Digitized Lithology and Geophysical Logs. Analysis Tools and Process Documents To develop the state-stewarded maps and models outlined above, new tools and process documents have been created to integrate and analyze a wide range of data, including geologic, geophysical, and hydrogeologic information. By combining and assessing various datasets, these tools help create a more complete picture of California's groundwater basins. All tools, along with guidance documents, are made publicly available for local groundwater managers to use to support development of maps and models at a local scale. All tools and guidance will be updated as revisions to tools and process documents are made. Data Analysis Tools Data2Texture: Data2Texture is an advanced spatial data interpolation tool for estimating the distribution of sediment textures from airborne electromagnetic data and lithology logs to create a 3D texture model Data2HSM - Smart Interpretation: Data2HSM via Smart Interpretation (SI) is a semi-automatic Python tool for delineating continuous hydrogeologic surfaces from airborne electromagnetic data products. Data2HSM - Gaussian Mixture Model: The Data2HSM via Gaussian Mixture Model tool ingests the AEM data and groups the data into a user-specified number of clusters that are interpreted as stratigraphic units in the hydrostratigraphic model (HSM) Data2HSM - Geological Pseudolabel Deep Neural Network: The GeoPDNN (Geological Pseudolabel Deep Neural Network) is a semi-supervised machine learning tool that integrates lithologic well logs and AEM data into plausible stratigraphic surfaces. Texture2Par V2: Texture2Par V2 is a groundwater model pre-processor and parameterization utility developed to work with the IWFM and MODFLOW families of hydrologic simulation code. Process Documents Aquifer Recharge Potential Mapping: The Aquifer Recharge Potential (ARP) Mapping Process Document provides a framework for identifying locations that have relatively higher potential for managed aquifer recharge. Data Visualization Data access equity is a priority for the Basin Characterization Program. To ensure data access equity, the Basin Characterization Program has developed applications and tools to allow data to be visualized without needing access to expensive data visualization software. This list below provides links and descriptions for the Basin Characterization's suite of data viewers. SGMA Data Viewer: Basin Characterization tab: Provides maps, depth slices, and profiles of Basin Characterization maps, models, and datasets, including the following: Aquifer Recharge Potential Maps Subsurface Texture Model Depth Slices Statewide AEM Survey Texture Depth Slices Lithology Log Location Maps Geophysical Logs Location Maps Statewide AEM Survey Profile Images 3D AEM Data Viewer: Displays the Statewide AEM Survey electrical resistivity and coarse fraction data, along with lithology logs, in a three-dimensional space. California's Groundwater Subsurface Viewer: Provides a map view and profile view of the Statewide AEM Survey electrical resistivity and coarse fraction data, along with lithology logs. The map view dynamically shows the exact location of AEM data displayed. Basin Characterization Exchange The Basin Characterization Exchange (BCX) is a meeting series and network space for the Basin Characterization community to exchange ideas, share lessons learned, define needed guidance, and highlight research topics. The BCX is open to federal, state, and local agencies, consultants, NGOs, academia, and interested parties who participate in Basin Characterization efforts. The BCX also plays a pivotal role in advancing the Basin Characterization Program’s activities and goals. BCX meetings will include regular updates from the Basin Characterization Program and participants can provide feedback and recommendations. Participants will also be provided with early opportunities to test data analysis tools and submit comments on draft process and guidance documents. BCX meetings are (generally) held the 3rd Tuesday of the month from 12:30 - 1:30 pm (PST). Join the BCX listserv to become a BCX member and receive meeting registration emails. Check the BCX Hub for the upcoming schedule and past meeting materials.

Statewide AEM Surveys Project Overview The Department of Water Resources’ (DWR’s) Statewide Airborne Electromagnetic (AEM) Surveys Project is funded through California’s Proposition 68 and the General Fund. The goal of the project is to improve the understanding of groundwater aquifer structure to support the state and local goal of sustainable groundwater management and the implementation of the Sustainable Groundwater Management Act (SGMA). During an AEM survey, a helicopter tows electronic equipment that sends signals into the ground which bounce back. The data collected are used to create continuous images showing the distribution of electrical resistivity values of the subsurface materials that can be interpreted for lithologic properties. The resulting information will provide a standardized, statewide dataset that improves the understanding of large-scale aquifer structures and supports the development or refinement of hydrogeologic conceptual models and can help identify areas for recharging groundwater. DWR collected AEM data in all of California’s high- and medium-priority groundwater basins, where data collection is feasible. Data were collected in a coarsely spaced grid, with a line spacing of approximately 2-miles by 8-miles. AEM data collection started in 2021 and was completed in 2023. Additional information about the project can be found on the Statewide AEM Survey website. See the publication below for an overview of the project and a preliminary analysis of the AEM data. California’s Statewide Airborne Electromagnetic Surveys and Preliminary Hydrogeologic Interpretations Survey Areas AEM data are being collected in groups of groundwater basins, defined as a Survey Area. See Survey Area Map for groundwater subbasins within a Survey Area: Survey Area 1: 180/400 Foot Aquifer (partial), East Side (partial), Upper Valley, Forebay Aquifer, Paso Robles, Atascadero (limited), Adelaida (limited), Cuyama Valley. Survey Area 2: Scott River Valley, Shasta Valley, Butte Valley, Tulelake, Fall River Valley (limited), Big Valley (Modoc/Lassen County). Survey Area 3: Big Valley (Lake County), Ukiah Valley, Santa Rosa Plain, Petaluma Valley, Sonoma Valley. Survey Area 4: White Wolf, Kern County, Tulare Lake, Tule, Kaweah. Survey Area 5: Pleasant Valley, Westside, Kings, Madera, Chowchilla, Merced, Turlock, Modesto, Delta-Mendota Survey Area 6: Cosumnes, Tracy, Eastern San Joaquin, East Contra Costa, Solano, Livermore, South American, North American, Yolo, Sutter, South Yuba, North Yuba Survey Area 7: Colusa, Butte, Wyandotte Creek, Vina, Los Molinos, Corning, Red Bluff, Antelope, Bowman, Bend, Millville, South Battle Creek, Anderson, Enterprise, Eel River, Sierra Valley Survey Area 8: Seaside, Monterey, 180/400 (partially surveyed Summer 2021), Eastside (partially surveyed Summer 2021), Langley, Pajaro, Santa Cruz Mid-County, Santa Margarita, San Benito, and Llagas (partial). Survey Area 9: Basin Characterization Pilot Study 1 - Madera and Kings. Survey Area 10: San Antonio Creek Valley, Arroyo Grande, Santa Maria, San Luis Obispo, Los Osos Area, Warden Creek, Chorro Valley (limited), Morro Valley (limited) Survey Area 11: Indian Wells Valley, Rose Valley, Owens Valley, Fish Slough, Indio, Mission Creek, West Salton Sea (limited), East Salton Sea (limited), Ocotillo-Clark Valley (limited), Imperial Valley (limited),Chocolate Valley (limited), Borrego Springs, and San Jacinto Data Reports Data reports detail the AEM data collection, processing, inversion, interpretation, and uncertainty analyses methods and procedures. Data reports also describe additional datasets used to support the AEM surveys, including digitized lithology and geophysical logs. Multiple data reports may be provided for a single Survey Area, depending on the Survey Area coverage. Data Availability and Types All data collected as a part of the Statewide AEM Surveys will be made publicly available, by survey area, approximately six to twelve months after individual surveys are complete (depending on survey area size). Datasets that will be publicly available include: AEM Datasets Raw AEM Data Processed AEM Data Inverted AEM Data Inverted AEM Data Uncertainty Analysis Interpreted AEM Data (for coarse fraction) Interpreted AEM Data Uncertainty Analysis Supporting Datasets Flown Survey Lines Digitized Lithology Logs Digitized Geophysical Logs AEM Data Viewers DWR has developed AEM Data Viewers to provides a quick and easy way to visualize the AEM electrical resistivity data and the AEM data interpretations (as texture) in a three-dimensional space. The most recent data available are shown, which my be the provisional data for some areas that are not yet finalized. The Data Viewers can be accessed by direct link, below, or from the Data Viewer Landing Page. AEM 3D Viewer (Beta) (computer only) AEM Profile Viewer SGMA Data Viewer (Basin Characterization tab) AEM Depth Slice and Shallow Subsurface Average Maps As a part of DWR’s upcoming Basin Characterization Program, DWR will be publishing a series of maps and tools to support advanced data analyses. The first of these maps have now been published and provide analyses of the Statewide AEM Survey data to support the identification of potential recharge areas. The maps are located on the SGMA Data Viewer (under the Hydrogeologic Conceptual Model tab) and show the AEM electrical resistivity and AEM-derived texture data as the following: Shallow Subsurface Average: Maps showing the average electrical resistivity and AEM-derived texture in the shallow subsurface (the top approximately 50 feet below ground surface). These maps support identification of potential recharge areas, where the top 50 feet is dominated by high resistivity or coarse-grained materials. Depth Slices: Depth slice automations showing changes in electrical resistivity and AEM-derived texture with depth. These maps aid in delineating the geometry of large-scale features (for example, incised valley fills). Shapefiles for the formatted AEM electrical resistivity data and AEM derived texture data as depth slices and the shallow subsurface average can be downloaded here: Electrical Resistivity Depth Slices and Shallow Subsurface Average Maps Texture Interpretation (Coarse Fraction) Depth Slices and Shallow Subsurface Average Maps Technical Memos Technical memos are developed by DWR's consultant team (Ramboll Consulting) to describe research related to AEM survey planning or data collection. Research described in the technical memos may also be formally published in a journal publication. AEM Test Flights to Evaluate the Bias Signal Caused by Vineyard Trellises Containing Metal SkyTEM Instrument Comparison for Airborne EM 2018-2020 AEM Pilot Studies Three AEM pilot studies were conducted in California from 2018-2020 to support the development of the Statewide AEM Survey Project. The AEM Pilot Studies were conducted in the Sacramento Valley in Colusa and Butte county groundwater basins, the Salinas Valley in Paso Robles groundwater basin, and in the Indian Wells Valley groundwater basin. Provisional Statement Data Reports and datasets labeled as provisional may be incomplete and are subject to revision until they have been thoroughly reviewed and received final approval. Provisional data and reports may be inaccurate and subsequent review may result in revisions to the data and reports. Data users are cautioned to consider carefully the provisional nature of the information before using it for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences.

Los Angeles Public Works has developed a groundwater well web viewer to provide the public with current and historical groundwater depth information throughout Los Angeles County.Purpose:To provide active wells information to the public.Supplemental Information:1. The State of California Department of Water Resources (DWR) developed the California Statewide Groundwater Elevation Monitoring (CASGEM) Program to make groundwater monitoring information available to the public through collaboration between local monitoring parties and DWR to collect groundwater elevation information statewide. The data have been compiled in the CASGEM Online System and made available to the public via the Internet with a GIS map interface. As a result, all interested parties can use the data to evaluate and monitor groundwater conditions in California.The CASGEM Online System will allow you to:• View lists of local agencies, counties and associations who have volunteered to serve as CASGEM Monitoring Entities providing groundwater data statewide• View CASGEM Monitoring Plans and Groundwater Management Plans (via hyperlink)• Search and view groundwater elevation data in tabular format• View hydrographs that show groundwater elevations for wells• Search and view groundwater monitoring well information• View mapped locations of CASGEM wells, monitoring area boundaries, and other geographic information• Measure distances between wells and size of monitoring areas and basins• Download well information, groundwater data, hydrographs and maps• Download summary reports on wells, groundwater elevations, Monitoring Entities and basin information.2. The State of California Department of Conservation developed the Division of Oil, Gas & Geothermal Resources Well Finder, which is a web viewer that allows the public to access information on oil, gas, and geothermal wells throughout the State.

Statewide AEM Surveys Project Overview

The Department of Water Resources’ (DWR’s) Statewide Airborne Electromagnetic (AEM) Surveys Project is funded through California’s Proposition 68 and the General Fund. The goal of the project is to improve the understanding of groundwater aquifer structure to support the state and local goal of sustainable groundwater management and the implementation of the Sustainable Groundwater Management Act (SGMA).

During an AEM survey, a helicopter tows electronic equipment that sends signals into the ground which bounce back. The data collected are used to create continuous images showing the distribution of electrical resistivity values of the subsurface materials that can be interpreted for lithologic properties. The resulting information will provide a standardized, statewide dataset that improves the understanding of large-scale aquifer structures and supports the development or refinement of hydrogeologic conceptual models and can help identify areas for recharging groundwater.

DWR collected AEM data in all of California’s high- and medium-priority groundwater basins, where data collection is feasible. Data were collected in a coarsely spaced grid, with a line spacing of approximately 2-miles by 8-miles. AEM data collection started in 2021 and was completed in 2023. Additional information about the project can be found on the Statewide AEM Survey website. See the publication below for an overview of the project and a preliminary analysis of the AEM data.

California’s Statewide Airborne Electromagnetic Surveys and Preliminary Hydrogeologic Interpretations

Survey Areas

AEM data are being collected in groups of groundwater basins, defined as a Survey Area. See Survey Area Map for groundwater subbasins within a Survey Area:

• Survey Area 1: 180/400 Foot Aquifer (partial), East Side (partial), Upper Valley, Forebay Aquifer, Paso Robles, Atascadero (limited), Adelaida (limited), Cuyama Valley.
• Survey Area 2: Scott River Valley, Shasta Valley, Butte Valley, Tulelake, Fall River Valley (limited), Big Valley (Modoc/Lassen County).
• Survey Area 3: Big Valley (Lake County), Ukiah Valley, Santa Rosa Plain, Petaluma Valley, Sonoma Valley.
• Survey Area 4: White Wolf, Kern County, Tulare Lake, Tule, Kaweah.
• Survey Area 5: Pleasant Valley, Westside, Kings, Madera, Chowchilla, Merced, Turlock, Modesto, Delta-Mendota
• Survey Area 6: Cosumnes, Tracy, Eastern San Joaquin, East Contra Costa, Solano, Livermore, South American, North American, Yolo, Sutter, South Yuba, North Yuba
• Survey Area 7: Colusa, Butte, Wyandotte Creek, Vina, Los Molinos, Corning, Red Bluff, Antelope, Bowman, Bend, Millville, South Battle Creek, Anderson, Enterprise, Eel River, Sierra Valley
• Survey Area 8: Seaside, Monterey, 180/400 (partially surveyed Summer 2021), Eastside (partially surveyed Summer 2021), Langley, Pajaro, Santa Cruz Mid-County, Santa Margarita, San Benito, and Llagas (partial).
• Survey Area 9: Basin Characterization Pilot Study 1 - Madera and Kings.
• Survey Area 10: San Antonio Creek Valley, Arroyo Grande, Santa Maria, San Luis Obispo, Los Osos Area, Warden Creek, Chorro Valley (limited), Morro Valley (limited)
• Survey Area 11: Indian Wells Valley, Rose Valley, Owens Valley, Fish Slough, Indio, Mission Creek, West Salton Sea (limited), East Salton Sea (limited), Ocotillo-Clark Valley (limited), Imperial Valley (limited),Chocolate Valley (limited), Borrego Springs, and San Jacinto

Data Reports

Data reports detail the AEM data collection, processing, inversion, interpretation, and uncertainty analyses methods and procedures. Data reports also describe additional datasets used to support the AEM surveys, including digitized lithology and geophysical logs. Multiple data reports may be provided for a single Survey Area, depending on the Survey Area coverage.

Data Availability and Types

All data collected as a part of the Statewide AEM Surveys will be made publicly available, by survey area, approximately six to twelve months after individual surveys are complete (depending on survey area size). Datasets that will be publicly available include:

AEM Datasets

• Raw AEM Data
• Processed AEM Data
• Inverted AEM Data
• Inverted AEM Data Uncertainty Analysis
• Interpreted AEM Data (for coarse fraction)
• Interpreted AEM Data Uncertainty Analysis

Supporting Datasets

• Flown Survey Lines
• Digitized Lithology and Geophysical Logs

NEW! Revisions to digitized lithology and geophysical logs

AEM Data Viewers

DWR has developed AEM Data Viewers to provides a quick and easy way to visualize the AEM electrical resistivity data and the AEM data interpretations (as texture) in a three-dimensional space. The most recent data available are shown, which my be the provisional data for some areas that are not yet finalized. The Data Viewers can be accessed by direct link, below, or from the Data Viewer Landing Page.

• AEM 3D Viewer (Beta) (computer only)

• AEM Profile Viewer

• SGMA Data Viewer (Basin Characterization tab)

AEM Depth Slice and Shallow Subsurface Average Maps

As a part of DWR’s upcoming Basin Characterization Program, DWR will be publishing a series of maps and tools to support advanced data analyses. The first of these maps have now been published and provide analyses of the Statewide AEM Survey data to support the identification of potential recharge areas. The maps are located on the SGMA Data Viewer (under the Hydrogeologic Conceptual Model tab) and show the AEM electrical resistivity and AEM-derived texture data as the following:

• Shallow Subsurface Average: Maps showing the average electrical resistivity and AEM-derived texture in the shallow subsurface (the top approximately 50 feet below ground surface). These maps support identification of potential recharge areas, where the top 50 feet is dominated by high resistivity or coarse-grained materials.

• Depth Slices: Depth slice automations showing changes in electrical resistivity and AEM-derived texture with depth. These maps aid in delineating the geometry of large-scale features (for example, incised valley fills).

Shapefiles for the formatted AEM electrical resistivity data and AEM derived texture data as depth slices and the shallow subsurface average can be downloaded here:

• Electrical Resistivity Depth Slices and Shallow Subsurface Average Maps

• Texture Interpretation (Coarse Fraction) Depth Slices and Shallow Subsurface Average Maps

Technical Memos

Technical memos are developed by DWR's consultant team (Ramboll Consulting) to describe research related to AEM survey planning or data collection. Research described in the technical memos may also be formally published in a journal publication.

• AEM Test Flights to Evaluate the Bias Signal Caused by Vineyard Trellises Containing Metal

• SkyTEM Instrument Comparison for Airborne EM

2018-2020 AEM Pilot Studies

Three AEM pilot studies were conducted in California from 2018-2020 to support the development of the Statewide AEM Survey Project. The AEM Pilot Studies were conducted in the Sacramento Valley in Colusa and Butte county groundwater basins, the Salinas Valley in Paso Robles groundwater basin, and in the Indian Wells Valley groundwater basin.

Provisional Statement

Data Reports and datasets labeled as provisional may be incomplete and are subject to revision until they have been thoroughly reviewed and received final approval. Provisional data and reports may be inaccurate and subsequent review may result in revisions to the data and reports. Data users are cautioned to consider carefully the provisional nature of the information before using it for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences.

Maintained by: DC GISOwner: DouglasCountyCO_GISServicesSource: Colorado Water Conservation Board, Department of Natural ResourcesEdit Frequency: NoneSummary: Data Including Feature Layer: Water Wells. Open Data. Water wells within Douglas County, Colorado. This data was a download of the "Well Applications" zipped shapefile from the Colorado Water Conservation Board, Department of Natural Resources GIS page (https://cdss.state.co.us/GIS/Pages/AllGISData.aspx). Once downloaded the query ("currstatus" = 'Well Constructed' AND "county" = 'DOUGLAS' AND "use1" = 'Domestic') was used to get the proper domestic wells. Then an identity was done with parcels to associate a SPN with each well. Lastly an append is done between the downloaded/identified feature class to DCGIS.WATER_WELLS where the SPN and receipt fields from the downloaded data are mapped to the PARCEL_SPN and MULTIPLE fields of DCGIS.WATER_WELLS. A hyperlink can be setup on the MULTIPLE field with "https://www.dwr.state.co.us/WellPermitSearch/View.aspx?receipt=" to get more information for each well. for information on setting up a hyperlink go to https://desktop.arcgis.com/en/arcmap/10.4/map/working-with-layers/using-hyperlinks.htm (make sure to look at the "Managing hyperlink paths" section to help remove the automatic "/" that will get put into the default hyperlink setting). full hyperlink example: https://www.dwr.state.co.us/WellPermitSearch/View.aspx?receipt=9016427mals); amphibian tunnels; fish ladders; Canopy bridge (especially for monkeys and squirrels), tunnels

NOTICE TO PROVISIONAL 2023 LAND USE DATA USERS: Please note that on December 6, 2024 the Department of Water Resources (DWR) published the Provisional 2023 Statewide Crop Mapping dataset. The link for the shapefile format of the data mistakenly linked to the wrong dataset. The link was updated with the appropriate data on January 27, 2025 and a notice was posted on the shapefile download site. If you downloaded the Provisional 2023 Statewide Crop Mapping dataset in shapefile format between December 6, 2024 and January 27, we encourage you to redownload the data. The Map Service and Geodatabase formats were correct as posted on December 06, 2024. Thank you for your interest in DWR land use datasets. The California Department of Water Resources (DWR) has been collecting land use data throughout the state and using it to develop agricultural water use estimates for statewide and regional planning purposes, including water use projections, water use efficiency evaluations, groundwater model developments, climate change mitigation and adaptations, and water transfers. These data are essential for regional analysis and decision making, which has become increasingly important as DWR and other state agencies seek to address resource management issues, regulatory compliances, environmental impacts, ecosystem services, urban and economic development, and other issues. Increased availability of digital satellite imagery, aerial photography, and new analytical tools make remote sensing-based land use surveys possible at a field scale that is comparable to that of DWR’s historical on the ground field surveys. Current technologies allow accurate large-scale crop and land use identifications to be performed at desired time increments and make possible more frequent and comprehensive statewide land use information. Responding to this need, DWR sought expertise and support for identifying crop types and other land uses and quantifying crop acreages statewide using remotely sensed imagery and associated analytical techniques. Currently, Statewide Crop Maps are available for the Water Years 2014, 2016, 2018- 2022 and PROVISIONALLY for 2023. Historic County Land Use Surveys spanning 1986 - 2015 may also be accessed using the CADWR Land Use Data Viewer: https://gis.water.ca.gov/app/CADWRLandUseViewer. For Regional Land Use Surveys follow: https://data.cnra.ca.gov/dataset/region-land-use-surveys. For County Land Use Surveys follow: https://data.cnra.ca.gov/dataset/county-land-use-surveys. For a collection of ArcGIS Web Applications that provide information on the DWR Land Use Program and our data products in various formats, visit the DWR Land Use Gallery: https://storymaps.arcgis.com/collections/dd14ceff7d754e85ab9c7ec84fb8790a.

Polygons depicting the watershed analysis units for the SWRCB's Drought Water Rights Allocation Tool (DWRAT), which assesses water supply against water demand. Attributes include the total water demand, allocation, and shortage, if any, for the lower Russian River Watershed (downstream of the Dry Creek confluence).Additional information about the SWRCB's Russian River drought response can be found at https://www.waterboards.ca.gov/drought/russian_river/For feedback about the map design, please email DWR@waterboards.ca.gov or call (916) 341-5300. For feedback about the underlying data or shortage determinations, please email RussianRiverDrought@waterboards.ca.gov or call (916) 341-5318.Field Descriptions:Field NameDescriptionData SourceData TypeareasqkmArea of the basin in square kilometersDWR staff analysisNumericareaacresArea of the basin in acresDWR staff analysisNumericGroupingIs the basin considered to be in the Upper Russian River or Lower Russian River?DWR staffTextBasin_IDUnique identifier for the DWRAT analysis unit (basin)DWR staffTextBasin_NumIdentifier associated with the Basin IDDWR staffNumericBasinRepeat of Basin_IDDWR staffTextnet_flowNet flow available in the basin as modeled by DWRAT, in acre-feetDWRAT ModelNumericaug_riparian_proportionsShared percentage of demand available in August for each riparian water right modeled in the basinDWR staff analysisNumericaug_rip_basin_allocationsModeled surface water supply available to water right, in acre-feet, for August 2021eWRIMS databaseNumericaug_rip_basin_demandSurface water demand for August, in acre-feet, based on previous reported water use amountsDWR staff analysisNumericaug_rip_basin_shortageWater shortage amount for August, in acre-feetDWR staff analysisNumericaug_rip_basin_shortage_%Water shortage for August, described as a percent of the demandDWRAT ModelNumericaug_app_basin_allocationsModeled surface water supply available to water right, in acre-feet, for August 2021DWRAT ModelNumericaug_app_basin_demandSurface water demand for August, in acre-feet, based on previous reported water use amountseWRIMS databaseNumericaug_app_basin_shortageWater shortage amount for August, in acre-feetDWR staff analysisNumericaug_app_basin_shortage_%Water shortage for August, described as a percent of the demandDWR staff analysisNumericsep_riparian_proportionsShared percentage of demand available in September for each riparian water right modeled in the basinDWRAT ModelNumericsep_rip_basin_allocationsModeled surface water supply available to water right, in acre-feet, for September 2021DWR staff analysisNumericsep_rip_basin_demandSurface water demand for September, in acre-feet, based on previous reported water use amountseWRIMS databaseNumericsep_rip_basin_shortageWater shortage amount for September, in acre-feetDWR staff analysisNumericsep_rip_basin_shortage_%Water shortage for September, described as a percent of the demandDWR staff analysisNumericsep_app_basin_allocationsModeled surface water supply available to water right, in acre-feet, for September 2021DWRAT ModelNumericsep_app_basin_demandSurface water demand for September, in acre-feet, based on previous reported water use amountseWRIMS databaseNumericsep_app_basin_shortageWater shortage amount for September, in acre-feetDWR staff analysisNumericsep_app_basin_shortage_%Water shortage for September, described as a percent of the demandDWR staff analysisNumeric

For many years, the California Department of Water Resources (DWR) has collected land use data throughout the state and used this information to develop water use estimates for statewide and regional planning efforts, including water use projections, water use efficiency evaluation, groundwater model development, and water transfers. These data are essential for regional analysis and decision making, which has become increasingly important as DWR and other state agencies seek to address resource management issues, regulatory compliance issues, environmental impacts, ecosystem services, urban and economic development, and other issues. Increased availability of digital satellite imagery, aerial photography and new analytical tools make remote sensing based land use surveys possible at a field scale that is comparable to that of DWR’s historical on the ground field surveys. Current technologies allow accurate, large-scale crop and land use identification to be performed at desired time increments, and make possible more frequent and comprehensive statewide land use information. Responding to this need, DWR sought expertise and support for identifying crop types and other land uses and quantifying crop acreages statewide using remotely sensed imagery and associated analytical techniques. Currently, Statewide Crop Maps are available for the Water Years 2014, 2016, 2018, 2019, 2020, 2021 and PROVISIONALLY for 2022.

Historic County Land Use Surveys spanning 1986 - 2015 may also be accessed using the CADWR Land Use Data Viewer: https://gis.water.ca.gov/app/CADWRLandUseViewer.

For Regional Land Use Surveys follow: https://data.cnra.ca.gov/dataset/region-land-use-surveys.

For County Land Use Surveys follow: https://data.cnra.ca.gov/dataset/county-land-use-surveys.

The County of Sacramento, Department of Water Resources (DWR) makes no representations about the suitability of the information contained in the documents and related graphics published on this document, disk, e-mail attachment, or server for any purpose. All such documents and related graphics are provided “as-is” without warranty of any kind. DWR hereby disclaims all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall DWR be liable for any special, indirect, or consequential damages or any damages whatsoever resulting from loss of use, data, or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of software, documents, provisions, or failure to provide services, or information available from this document, disk, e-mail attachment, or server.

This document and related graphics published on this document, disk, e-mail attachment, or server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Furthermore, DWR and/or its respective suppliers may make improvements and/or changes in the product(s) and/or service(s) described herein at any time.Sacramento County Department of Water Resources

The ETo Zones Map allows users to view the grass-reference evapotranspiration (ETo) Zones for the State of California. The map was developed by DWR and UC Davis in 1999 and divides the State into 18 zones based on long-term monthly average ETo. The ETo values were calculated using data from various data sources, including CIMIS weather stations that had at least five years of archived data. This dataset is the version from 1999.

Points depicting the water rights in the lower Russian River Watershed, as found in SWRCB's eWRIMS database. Attributes include the total water demand, allocation, and shortage, if any, for water rights in the lower Russian River Watershed (downstream of the Dry Creek confluence).Additional information about the SWRCB's Russian River drought response can be found at https://www.waterboards.ca.gov/drought/russian_river/For feedback about the map design, please email DWR@waterboards.ca.gov or call (916) 341-5300. For feedback about the underlying data or shortage determinations, please email RussianRiverDrought@waterboards.ca.gov or call (916) 341-5318.Field Descriptions:Field NameDescriptionData SourceData TypeAPPLICATIOWater right identification numbereWRIMS databaseAlphanumericLATITUDEPOD latitude in decimal degrees, NAD83eWRIMS databaseNumericLONGITUDEPOD longitude in decimal degrees, NAD83eWRIMS databaseNumericWATER_RIGHWater right typeeWRIMS databaseTextWATER_RI_1Water right processing statuseWRIMS databaseTextPRIMARY_OWWater right holder typeeWRIMS databaseTextPRIMARY_1Water right holder nameeWRIMS databaseTextPOD_STATUSStatus of point of diversioneWRIMS databaseTextSOURCE_TYPSource typeeWRIMS databaseTextPOD_NAMEName of point of diversioneWRIMS databaseTextPOD_TYPEType of point of diversioneWRIMS databaseTextAPPL_PODConcatenation of the APPL_ID and POD_NUMBEReWRIMS databaseTextSOURCE_NAMGNIS name of the nearest high-resolution NHD feature to diversioneWRIMS databaseTextTRIB_DESCNarrative description of source tributaryeWRIMS databaseTextGroupingIs the water right considered to be in the Upper Russian River or Lower Russian River?DWR staffTextBasinOvrrdManual correction for basin assignment of a water rightDWR staffTextMnstmDryCIs the water right's suspected or listed source mainstem Dry Creek?DWR staffTextMnstm_RRIs the water right's suspected or listed source mainstem Russian River?DWR staffTextMnstm_EFRRIs the water right's suspected or listed source mainstem East Fork Russian River?DWR staffTextMnstm_MWCkIs the water right's suspected or listed source mainstem Mark West Creek?DWR staffTextBasin_IDUnique identifier for the DWRAT analysis unit (basin) in which the water right is locatedDWR staffTextMnstmIs the water right's suspected or listed source the mainstem of one the selected streams?DWR staffTextSmblgyCodeCode used for symbolization of the water right in the mapDWR staffTextUSERWater right identification number (repeated field)eWRIMS databaseAlphanumericBASINUnique identifier for the DWRAT analysis unit (basin) in which the water right is located; Values may differ slightly from those in the "Basin_ID" fieldDWR staffTextRIPARIANIs the water right a Riparian water right?eWRIMS databaseTextPRIORITYAssigned water rights priority numbereWRIMS databaseNumeric2021-10_ALLOCATIONModeled surface water supply available to water right, in acre-feet, for August 2021DWRAT ModelNumeric2021-10_DEMANDSurface water demand for August, in acre-feet, based on previous reported water use amountseWRIMS databaseNumeric2021-10_SHORTAGEWater shortage amount for August, in acre-feetDWR staff analysisNumeric2021-10_%_SHORTAGEWater shortage for August, described as a percent of the demandDWR staff analysisNumericSHORTAGE_YNIs there a water shortage for the water right in September?DWR staff analysisText

Walk In Access, or WIA, areas are tracts of private land which the Utah Division of Wildlife Resources leases for the purpose of providing free public access for fishing, hunting, wildlife viewing, or trapping. This dataset represents point features such as parking areas and access points.This data is general reference for administrative and public use.

The California Department of Water Resources (DWR), North Central Region Office (NCRO), Bathymetry Data Collection Section, conducted a singlebeam bathymetric survey of Elkhorn Slough as part of the Delta Wide Bathymetry Program. The main purpose of the data is to help supplement bathymetric datasets of the North Delta and allow for relevant comparisons. • Field Dates: January 26, February 14, 2023 • Survey Type: Singlebeam • Data Density: 1 foot • Horizontal Datum: North American Datum of 1983 (NAD83) California Coordinate System (CCS83) State Plane Zone 2, US feet • Vertical Datum: North American Vertical Datum of 1988 (NAVD88) geoid 12B, US feet • Processing Epoch: 2023.123; CSRC Datum Epoch: 2017.5 • Related Datasets: Sutter Slough at Sacramento River 2017 • Involved Staff: Data collected and processed by NCRO Bathymetry and Hydrography sections • Survey Responsible Charge: Jacob Wright, PLS (CA 8717)Please contact the distributor for questions regarding survey control or QC checks. For complete metadata make sure the viewer (ArcGIS or other software) is set to view FGDC metadata.

This statewide shapefile contains all Outstanding Resource Water and High Quality Water management areas. To learn more about what these are, see the Classifications and Standards/Rule Review Branch website. This data layer was first uploaded on March 6, 2015 and originally exported from BIMS November 2014. Attributes:Acreage: Area of the polygonName: Name of the management areaRiv_Basin: River BasinClass: ClassificationDownload Shapefile: DownloadData Contact: Elizabeth KountisLayer/Service Contact: Melanie Williams

Integrated Report 2022 (references)The NC Department of Environmental Quality’s Integrated Water Quality Report checks to see if North Carolina’s waterways meet federal and state standards every two years. It incorporates information from multiple data sources, such as local monitoring programs and voluntary work, to group bodies of water into five categories:Category 1: Waters meet all standards.Category 2: Waters meet some standards.Category 3: Waters lacking enough data.Category 4: Impaired waters with a plan.Category 5: Impaired water and need a plan.The data varies in quality and coverage, and not all water bodies are monitored equally, leading to some limitations in assessing smaller or remote areas.https://www.deq.nc.gov/about/divisions/water-resources/water-planning/modeling-assessment/water-quality-data-assessmenthttps://ncdenr.maps.arcgis.com/apps/instant/sidebar/index.html?appid=06dda86e607b4ac6861b19b905c82a8fhttps://ncdenr.maps.arcgis.com/apps/mapviewer/index.html?layers=37696e11dac34786bdc94db84d54ff70NC DEQ AFO ANIMAL FEEDING OPERATION:The AFO (Animal Feeding Operations) program at NC DEQ manages permit applications for big farm operations, such as those raising hogs, chickens and cows. These farms have to comply with regulations on the disposal of waste for water quality reasons. The permits are reviewed every five years to make sure that they’re up to date. Program data are collected through inspections and reports, but they don’t always provide an accurate picture of the environmental impact, and tracking varies by farm. Its limitations are inconsistencies of data and incomplete monitoring of waste management at every site.https://www.deq.nc.gov/about/divisions/water-resources/permitting/animal-feeding-operationsNC Surface Water Supply WatershedsIn NC DEQ’s Surface Water Supply Watersheds maps, waterbodies are assigned to uses such as drinking water, swimming or fishing. These categories set the boundaries for water quality management to safeguard public health and ecosystems. They are based on water monitoring systems and scientific research, but the uncertainties are fluctuating water quality and monitoring performance. These classifications might have to be updated as water use varies.https://www.deq.nc.gov/about/divisions/water-resources/water-planning/classification-standards/classificationsNPDES Wastewater Discharge PermitsNPDES Wastewater Discharge Permits regulate treatment facilities’ discharge of treated wastewater into rivers and lakes to protect water quality. The permits cap the concentration of contaminants according to the water in place. They are the result of daily monitoring and assessments, though sometimes facilities can vary how these are tracked and reported which can impact the consistency of enforcement.https://www.deq.nc.gov/about/divisions/water-resources/permitting/npdes-wastewaterDWR FISH TISSUE MONITORING DATAThe DWR Fish Tissue Monitoring Program inspects North Carolina waterways for heavy metals, pesticides and PCBs (Polychlorinated Biphenyls). PCBs are industrial chemicals that build up in fish, and they are harmful if consumed. It’s data that are used to issue fish-consumption advisories to help keep people safe. They collect samples by electrofishing (which consists of fish that humans eat). Constraints: data are not collected in every watershed, and older data don’t necessarily reflect recent pollution.https://www.deq.nc.gov/about/divisions/water-resources/water-sciences/biological-assessment-branch/dwr-fish-tissue-monitoring-data

Delta Primary Zone Boundary The history of the primary zone boundary is as follows: the Primary Zone was defined in the 1992 Delta Flood Protection Act by referring to a map attached to the legislation, on file with the Secretary of State. See Public Resources Code section 29728. The map was submitted by the Delta Protection Commission. It is a large extent (small scale) map, with no real controls, little or no reference marks or guides of any kind, and no legal description. As such, from a mapping point of view, it leaves much to be desired. Nevertheless, by law, this map defines the Primary Zone boundary. Sometime shortly after the law was passed, DWR Land & Right of Way drew the boundary on 24k topo maps which also had the precise, agreed-upon legal Delta boundary. There are some significant differences between the DWR version and the official version. In asking current DWR Land & Right of Way staff (Carrol Leong & Fred Mau), there was no readily-available explanation, and the person who originally conducted it is no longer there. That is unfortunate, because not only are these maps much more "accuracy friendly", but there may have been good reasons why the boundary was drawn as such. This is the Delta primary zone boundary. It was drawn by Joel Dudas on November 27, 2002, as described below. It was drawn at the request of Margit Arambru, Delta Protection Commission. The legal Delta/primary zone effort conducted by Chico State had raised questions about the primary zone boundary, and upon inspection of the issue it has been determined that there is no precise solution available at this time. Lori Clamurro & Margit Arambru indicated that this delineation was acceptable to them upon review (12/8/2002). METHOD: There were significant errors in the paper base map, as evidenced by errors in the locations of roads, watercourses, and the legal Delta boundary itself. Due to these significant problems posed by the errors inherent in the paper base map, the base map was used as a guide, rather than as a literal translation, to locate the primary zone boundary. Furthermore, a second significant assumption was made, namely that the intent of the Primary Zone map was to indicate that the legal boundary and the primary zone boundary are one and the same in many places, but that mapping this would not result in distinguishable lines if they were literally drawn atop each other, and they therefore were lined up adjacent to one another (on the source paper map!), with the gap being as small as possible but also being far enough apart to clearly distinguish the two lines. Therefore, for GIS purposes, the shapefile was created by tracing the legal boundary line wherever this was felt to be appropriate. The third major assumption was that, in places where the primary zone and the legal boundary are separated, the primary zone boundary was equivalent to the primary zone boundary drawn by DWR Land & Right of Way on the higher accuracy 24k maps in all places except where significant deviations obviously occurred as indicated by the official paper base map. The rationale for this is that the 24k map does a better job delineating the boundary according to actual features (watercourses, rec district boundaries, etc.) where the intended boundary was clearly the same, but where the paper map simply cannot represent this intent accurately. However, in places where the intent clearly shows a discrepancy from the "higher accuracy" line, the boundary on the paper base map was literally traced. Delta Secondary Zone Boundary The parent of this file was one of the Delta Vision Status & Trends shapefiles. Published in 4/2007. The change to the boundary near Van Sickle was made subsequent to delivery to DWR on 10/8/2009. Also, offsets versus the legal Delta boundary were corrected by DWR on 10/22/2009. At this time, unless better information becomes available, it is therefore felt that these are the best boundaries available.

This is collection of DWR County Land Use Surveys. You may scroll the list below to download any individual survey of interest. Historic County Land Use Surveys spanning 1986 - 2015 may also be accessed using the CADWR Land Use Data Viewer. For Statewide Crop Mapping follow the link below : https://data.cnra.ca.gov/dataset/statewide-crop-mapping For Region Land Use Surveys follow link below: https://data.cnra.ca.gov/dataset/region-land-use-surveys Questions about the survey data may be directed to Landuse@water.ca.gov.