This geologic map database is a reproduction of U.S. Geological Survey Miscellaneous Investigations Map I–2362: “Geologic Map and Structure Sections of the Clear Lake Volcanics, Northern California” (Hearn, Donnelly-Nolan, and Goff, 1995). The database consists of a geologic map, three structural cross sections and a table of petrographic data for each map unit by mineral type, abundance, and size. The Clear Lake Volcanics are in the California Coast Ranges about 150 km north of San Francisco. This Quaternary volcanic field has erupted intermittently since 2.1 million years ago. This volcanic field is considered a high-threat volcanic system (Ewert and others, 2005). The adjacent Geysers geothermal field, the largest power-producing geothermal field in the world, is powered by the magmatic heat source for the volcanic field. The geology of parts of the area underlain by the Cache Formation is based on mapping by Rymer (1981); the geology of parts of the areas underlain by the Sonoma Volcanics, Franciscan assemblage, and Great Valley sequence is based on mapping by McLaughlin (1978). Volcanic compositional map units are basalt, basaltic andesite, andesite, dacite, rhyodacite, and rhyolite, based on SiO2 content. Most ages are potassium-argon (K/Ar) ages determined for whole-rock samples and mineral separates by Donnelly-Nolan and others (1981), unless otherwise noted. A few ages are carbon-14 ages or were estimated from geologic relationships. Magnetic polarities are from Mankinen and others (1978; 1981) or were determined in the field by B.C. Hearn, Jr., using a portable fluxgate magnetometer. Thickness for most units is estimated from topographic relief except where drill-hole data were available. This database does not reproduce all elements of the original publication. Omissions include the chart and figures showing erupted volumes of different lava types through time, and the chart and diagram for the correlation of map units. Users of this database are highly encouraged to cross reference this database with the original publication.

description: In 1986 and 1987, Pelagos Corporation of San Diego (now Racal Pelagos) undertook a bathymetric survey of Mono Lake in eastern California for the Los Angeles Department of Water and Power (DWP). The result of that survey was a series of maps at various scales and contour intervals. From these maps, the DWP hoped to predict consequences of the drop in lake level that resulted from their diversion of streams in the Mono Basin. No digital models, including shaded-relief and perspective-view renderings, were made from the data collected during the survey. With the permission of Pelagos Corporation and DWP, these data are used to produce a digital model of the floor of Mono Lake. The model was created using a geographic information system (GIS) to incorporate these data with new observations and measurements made in the field. This model should prove to be a valuable tool for enhanced visualization and analyses of the floor of Mono Lake.; abstract: In 1986 and 1987, Pelagos Corporation of San Diego (now Racal Pelagos) undertook a bathymetric survey of Mono Lake in eastern California for the Los Angeles Department of Water and Power (DWP). The result of that survey was a series of maps at various scales and contour intervals. From these maps, the DWP hoped to predict consequences of the drop in lake level that resulted from their diversion of streams in the Mono Basin. No digital models, including shaded-relief and perspective-view renderings, were made from the data collected during the survey. With the permission of Pelagos Corporation and DWP, these data are used to produce a digital model of the floor of Mono Lake. The model was created using a geographic information system (GIS) to incorporate these data with new observations and measurements made in the field. This model should prove to be a valuable tool for enhanced visualization and analyses of the floor of Mono Lake.

Tax rate area boundaries and related data based on changes filed with the Board of Equalization per Government Code 54900 for the specified assessment roll year. The data included in this map is maintained by the California State Board of Equalization and may differ slightly from the data published by other agencies. BOE_TRA layer = tax rate area boundaries and the assigned TRA number for the specified assessment roll year; BOE_Changes layer = boundary changes filed with the Board of Equalization for the specified assessment roll year; Data Table (C##_YYYY) = tax rate area numbers and related districts for the specified assessment roll year

The Digital Geologic-GIS Map of the Lake Eleanor Quadrangle, California is composed of GIS data layers and GIS tables, and is available in the following GRI-supported GIS data formats: 1.) a 10.1 file geodatabase (lael_geology.gdb), and a 2.) Open Geospatial Consortium (OGC) geopackage. The file geodatabase format is supported with a 1.) ArcGIS Pro map file (.mapx) file (lael_geology.mapx) and individual Pro layer (.lyrx) files (for each GIS data layer), as well as with a 2.) 10.1 ArcMap (.mxd) map document (lael_geology.mxd) and individual 10.1 layer (.lyr) files (for each GIS data layer). Upon request, the GIS data is also available in ESRI 10.1 shapefile format. Contact Stephanie O'Meara (see contact information below) to acquire the GIS data in these GIS data formats. In addition to the GIS data and supporting GIS files, three additional files comprise a GRI digital geologic-GIS dataset or map: 1.) A GIS readme file (yose_geology_gis_readme.pdf), 2.) the GRI ancillary map information document (.pdf) file (yose_geology.pdf) which contains geologic unit descriptions, as well as other ancillary map information and graphics from the source map(s) used by the GRI in the production of the GRI digital geologic-GIS data for the park, and 3.) a user-friendly FAQ PDF version of the metadata (lael_geology_metadata_faq.pdf). Please read the yose_geology_gis_readme.pdf for information pertaining to the proper extraction of the GIS data and other map files. QGIS software is available for free at: https://www.qgis.org/en/site/. The data were completed as a component of the Geologic Resources Inventory (GRI) program, a National Park Service (NPS) Inventory and Monitoring (I&M) Division funded program that is administered by the NPS Geologic Resources Division (GRD). For a complete listing of GRI products visit the GRI publications webpage: For a complete listing of GRI products visit the GRI publications webpage: https://www.nps.gov/subjects/geology/geologic-resources-inventory-products.htm. For more information about the Geologic Resources Inventory Program visit the GRI webpage: https://www.nps.gov/subjects/geology/gri,htm. At the bottom of that webpage is a "Contact Us" link if you need additional information. You may also directly contact the program coordinator, Jason Kenworthy (jason_kenworthy@nps.gov). Source geologic maps and data used to complete this GRI digital dataset were provided by the following: U.S. Geological Survey. Detailed information concerning the sources used and their contribution the GRI product are listed in the Source Citation section(s) of this metadata record (lael_geology_metadata.txt or lael_geology_metadata_faq.pdf). Users of this data are cautioned about the locational accuracy of features within this dataset. Based on the source map scale of 1:62,500 and United States National Map Accuracy Standards features are within (horizontally) 31.8 meters or 104.2 feet of their actual location as presented by this dataset. Users of this data should thus not assume the location of features is exactly where they are portrayed in ArcGIS, QGIS or other software used to display this dataset. All GIS and ancillary tables were produced as per the NPS GRI Geology-GIS Geodatabase Data Model v. 2.3. (available at: https://www.nps.gov/articles/gri-geodatabase-model.htm).

Tax rate area boundaries and related data based on changes filed with the Board of Equalization per Government Code 54900 for the specified assessment roll year. The data included in this map is maintained by the California State Board of Equalization and may differ slightly from the data published by other agencies. BOE_TRA layer = tax rate area boundaries and the assigned TRA number for the specified assessment roll year; BOE_Changes layer = boundary changes filed with the Board of Equalization for the specified assessment roll year; Data Table (C##_YYYY) = tax rate area numbers and related districts for the specified assessment roll year

Percent of each freshwater ecoregion’s area covered with lakes and man-made reservoirs.

We calculated the percentage of the ecoregion that is covered by lakes and reservoirs using lake and reservoir polygons from the Global Lakes and Wetlands Database (GLWD) (Lehner and Döll 2004). This database represents the best available source for lakes and wetlands on a global scale (1:1 to 1:3 million resolution). The GLWD contains shoreline polygons of the 3,067 largest lakes (surface area greater than or equal to 50 km2) and 654 largest reservoirs (storage capacity greater than or equal to 0.5 km3) worldwide, as well as shoreline polygons of approximately 250,000 smaller lakes, reservoirs, and rivers (surface area greater than or equal to 0.1 km2). For our calculations, only lake and reservoir polygons were used. It was not possible to separate natural lake polygons from reservoirs.

These data were derived by The Nature Conservancy, and were displayed in a map published in The Atlas of Global Conservation (Hoekstra et al., University of California Press, 2010). More information at http://nature.org/atlas.

Data derived from:

Lehner, B., and P. Döll. 2004. Development and validation of a global database of lakes, reservoirs and wetlands. Journal of Hydrology 296: 1–22.

These data were derived by The Nature Conservancy, and were displayed in a map published in The Atlas of Global Conservation (Hoekstra et al., University of California Press, 2010). More information at http://nature.org/atlas.

For more about The Atlas of Global Conservation check out the web map (which includes links to download spatial data and view metadata) at http://maps.tnc.org/globalmaps.html. You can also read more detail about the Atlas at http://www.nature.org/science-in-action/leading-with-science/conservation-atlas.xml, or buy the book at http://www.ucpress.edu/book.php?isbn=9780520262560

The Digital Geologic-GIS Map of the Bass Lake Quadrangle, California is composed of GIS data layers and GIS tables, and is available in the following GRI-supported GIS data formats: 1.) a 10.1 file geodatabase (bala_geology.gdb), and a 2.) Open Geospatial Consortium (OGC) geopackage. The file geodatabase format is supported with a 1.) ArcGIS Pro map file (.mapx) file (bala_geology.mapx) and individual Pro layer (.lyrx) files (for each GIS data layer), as well as with a 2.) 10.1 ArcMap (.mxd) map document (bala_geology.mxd) and individual 10.1 layer (.lyr) files (for each GIS data layer). Upon request, the GIS data is also available in ESRI 10.1 shapefile format. Contact Stephanie O'Meara (see contact information below) to acquire the GIS data in these GIS data formats. In addition to the GIS data and supporting GIS files, three additional files comprise a GRI digital geologic-GIS dataset or map: 1.) A GIS readme file (yose_geology_gis_readme.pdf), 2.) the GRI ancillary map information document (.pdf) file (yose_geology.pdf) which contains geologic unit descriptions, as well as other ancillary map information and graphics from the source map(s) used by the GRI in the production of the GRI digital geologic-GIS data for the park, and 3.) a user-friendly FAQ PDF version of the metadata (bala_geology_metadata_faq.pdf). Please read the yose_geology_gis_readme.pdf for information pertaining to the proper extraction of the GIS data and other map files. QGIS software is available for free at: https://www.qgis.org/en/site/. The data were completed as a component of the Geologic Resources Inventory (GRI) program, a National Park Service (NPS) Inventory and Monitoring (I&M) Division funded program that is administered by the NPS Geologic Resources Division (GRD). For a complete listing of GRI products visit the GRI publications webpage: For a complete listing of GRI products visit the GRI publications webpage: https://www.nps.gov/subjects/geology/geologic-resources-inventory-products.htm. For more information about the Geologic Resources Inventory Program visit the GRI webpage: https://www.nps.gov/subjects/geology/gri,htm. At the bottom of that webpage is a "Contact Us" link if you need additional information. You may also directly contact the program coordinator, Jason Kenworthy (jason_kenworthy@nps.gov). Source geologic maps and data used to complete this GRI digital dataset were provided by the following: U.S. Geological Survey. Detailed information concerning the sources used and their contribution the GRI product are listed in the Source Citation section(s) of this metadata record (bala_geology_metadata.txt or bala_geology_metadata_faq.pdf). Users of this data are cautioned about the locational accuracy of features within this dataset. Based on the source map scale of 1:62,500 and United States National Map Accuracy Standards features are within (horizontally) 31.8 meters or 104.2 feet of their actual location as presented by this dataset. Users of this data should thus not assume the location of features is exactly where they are portrayed in ArcGIS, QGIS or other software used to display this dataset. All GIS and ancillary tables were produced as per the NPS GRI Geology-GIS Geodatabase Data Model v. 2.3. (available at: https://www.nps.gov/articles/gri-geodatabase-model.htm).

Tax rate area boundaries and related data based on changes filed with the Board of Equalization per Government Code 54900 for the specified assessment roll year. The data included in this map is maintained by the California State Board of Equalization and may differ slightly from the data published by other agencies. BOE_TRA layer = tax rate area boundaries and the assigned TRA number for the specified assessment roll year; BOE_Changes layer = boundary changes filed with the Board of Equalization for the specified assessment roll year; Data Table (C##_YYYY) = tax rate area numbers and related districts for the specified assessment roll year

Medicine Lake, California Well Locations

This geologic map database is comprised of new geologic mapping, at a 1:24,000 scale, along the southern Bartlett Springs fault in the northern California Coast Ranges. The map covers an area of 258 square miles in Lake, Napa, Colusa, and Yolo counties, work was undertaken between 2016 and 2021, and supported by the USGS National Cooperative Geologic Map Program. This geodatabase contains the most up-to-date and highest resolution mapping in the region. Results and observations reported here help elucidate the geologic deformational history, as well as relationships between active older and active structures. Please consult the map pamphlet and description of map units for a detailed presentation and interpretation of data and discussion of results. The report and geodatabase contain two plates including the geologic map as well as a correlation of map units, four geologic cross sections, six microseismic cross sections, and a microseismicity fault map.

Abstract not available.

Tax rate area boundaries and related data based on changes filed with the Board of Equalization per Government Code 54900 for the specified assessment roll year. The data included in this map is maintained by the California State Board of Equalization and may differ slightly from the data published by other agencies. BOE_TRA layer = tax rate area boundaries and the assigned TRA number for the specified assessment roll year; BOE_Changes layer = boundary changes filed with the Board of Equalization for the specified assessment roll year; Data Table (C##_YYYY) = tax rate area numbers and related districts for the specified assessment roll year

Abstract not available.

An isostatic residual gravity map of the Big Bear Lake 100,000 scale quadrangle, California was prepared and then this data set used with other information to compute the configuration of several ground water basins. Basin thickness maps were then prepared.

On October 13, 2020 a survey of Upper Letts Lake was conducted where both bathymetric and terrestrial lidar data were collected. Additionally, six bed material samples and three core samples were collected to understand the characterization of the grain-size of the lake bed. Survey data were merged with an additional lidar dataset from the USGS 3DEP program to create digital elevation model (DEM). The DEM was used to update the stage-storage and stage-surface area tables for the reservoir. This data release provides the following data sets; 1) bathymetric and terrestrial elevation data, 2) Combined bathymetric and 3DEP DEM, 3) stage-storage and stage-surface area tables from DEM, and 4) bed material grain-size and loss of ignition results (percent organics). Results show that the storage for the Upper Letts Lake is 377 acre-feet with a surface area of 34.5 acre at the elevation of the spillway outlet. Bed material samples show that the median diameter of the bed ranges from 0.044 ...

description: This geologic map database for the El Mirage Lake area describes geologic materials for the dry lake, parts of the adjacent Shadow Mountains and Adobe Mountain, and much of the piedmont extending south from the lake upward toward the San Gabriel Mountains. This area lies within the western Mojave Desert of San Bernardino and Los Angeles Counties, southern California. The area is traversed by a few paved highways that service the community of El Mirage, and by numerous dirt roads that lead to outlying properties. An off-highway vehicle area established by the Bureau of Land Management encompasses the dry lake and much of the land north and east of the lake. The physiography of the area consists of the dry lake, flanking mud and sand flats and alluvial piedmonts, and a few sharp craggy mountains. This digital geologic map database, intended for use at 1:24,000- scale, describes and portrays the rock units and surficial deposits of the El Mirage Lake area. It was prepared as part of a water-resource assessments of the area, describing and interpreting surface geology that provides information to help understand distribution and extent of deeper groundwater-bearing units. The area mapped covers the Shadow Mountains SE and parts of the Shadow Mountains, Adobe Mountain, and El Mirage 7.5-minute quadrangles. The map database includes detailed geology of surface and bedrock deposits, which represent a significant update from previous bedrock geologic maps by Dibblee (1960) and Troxel and Gunderson (1970), and the surficial geologic map of Ponti and Burke (1980); it incorporates a fringe of the detailed bedrock mapping in the Shadow Mountains by Martin (1992).; abstract: This geologic map database for the El Mirage Lake area describes geologic materials for the dry lake, parts of the adjacent Shadow Mountains and Adobe Mountain, and much of the piedmont extending south from the lake upward toward the San Gabriel Mountains. This area lies within the western Mojave Desert of San Bernardino and Los Angeles Counties, southern California. The area is traversed by a few paved highways that service the community of El Mirage, and by numerous dirt roads that lead to outlying properties. An off-highway vehicle area established by the Bureau of Land Management encompasses the dry lake and much of the land north and east of the lake. The physiography of the area consists of the dry lake, flanking mud and sand flats and alluvial piedmonts, and a few sharp craggy mountains. This digital geologic map database, intended for use at 1:24,000- scale, describes and portrays the rock units and surficial deposits of the El Mirage Lake area. It was prepared as part of a water-resource assessments of the area, describing and interpreting surface geology that provides information to help understand distribution and extent of deeper groundwater-bearing units. The area mapped covers the Shadow Mountains SE and parts of the Shadow Mountains, Adobe Mountain, and El Mirage 7.5-minute quadrangles. The map database includes detailed geology of surface and bedrock deposits, which represent a significant update from previous bedrock geologic maps by Dibblee (1960) and Troxel and Gunderson (1970), and the surficial geologic map of Ponti and Burke (1980); it incorporates a fringe of the detailed bedrock mapping in the Shadow Mountains by Martin (1992).

Medicine Lake Map

Geologic map of the Lake Tahoe Basin, California and Nevada, Scale 1:100,000. This map is available as an interactive map, downloadable PDF, and for purchase by contacting the California Geological Survey. For more information see the links provided.

State Water Resources Control Board Division of Water Quality staff have developed this map to graphically display the waterbodies assessed in the 2018 California Integrated Report. This map contains waterbodies assessed for 305(b) categorization, including those placed on the 303(d) list of impaired waters.Map Layers and Table:2018 Integrated Report Streams, Rivers, and Beaches: Spatial representation of the assessed linear waterbodies in California.2018 Integrated Report Lakes, Bays, and Reservoirs: Spatial representation of the non-linear (polygon) waterbodies in California. The layers can also be accessed here: https://gispublic.waterboards.ca.gov/portalserver/rest/services/Hosted/CA_2018_Integrated_Report_Assessed_Lines_and_Polys/FeatureServerHow to Use the Map:Navigate to your point of interest by either using the search bar in the upper left-hand corner of the map or by zooming in on the map. You may enter a waterbody name or address into the search bar. Click on a waterbody of interest, such as a river, lake, or beach, and a pop-up box will appear with a summary of the pollutant assessments conducted for that waterbody. Select the ellipsis ("...") in a pop-up window or the layers to view the attribute table. This table can be further filtered and exported in a tabular format. Click on the layers icon in the upper right hand corner to toggle map layers on and off.Click on the filter button in the upper right corner to filter for a specific Regional Board and to select for 303(d) listed waterbodies only. Note, this should be done for both layers.More details on each waterbody can be found by scrolling to the bottom of a waterbody pop-up and selecting “Waterbody Fact Sheet- More information”.Pop Up Description:WBID: Unique identifier for each waterbody used in the Integrated Report. Waterbody Name: Name of the mapped waterbody assessed for the Integrated Report. Waterbody Type: Type of water (Coastal & Bay Shoreline, Freshwater Wetland, Tidal Wetland, Saline Lake, River & Stream, Ocean, Lake and Reservoir, Estuary, and Bay & Harbor).Regional Board: Which Regional Water Quality Control Board has jurisdiction over the waterbody. Waterbody Condition Category: Integrated Report 305(b) Category for the waterbody.Waterbody Listing Status: If the waterbody has been placed on the 303(d) list as impaired for one or more pollutant, it will be identified as "Listed". If it was assessed for one or more pollutant and not determined to be impaired, it will be identified as "Not Listed". Listed Pollutants: Pollutants identified as impairing the waterbody's support of beneficial uses. The Decision ID is included in parentheses. Listings Addressed by a TMDL: Pollutant impairments in the waterbody being addressed by an adopted Total Maximum Daily Load (TMDL)Listings Addressed by Action other than TMDL: Pollutant impairments in the waterbody being addressed by actions other than a TMDL. These may also be referred to as Category “4b” decisions.Pollutants Assessed, Not Listed: Pollutant assessments that did not result in a 303(d) impairment decision for the waterbody.Waterbody Fact Sheet: Link to the Waterbody Fact Sheet for the waterbody, which includes waterbody/pollutant assessment information. For additional data and information about the 2018 Integrated Report assessments, please visit our Data Download page: (coming soon!)For more information about the Integrated Report (the 305(b) Report and the 303(d) List), how it is created, or how this information is used, please see the program webpage: https://www.waterboards.ca.gov/water_issues/programs/water_quality_assessment/Please contact the SWRCB Water Quality Assessment Program with any questions, at WQAssessment@waterboards.ca.gov. Origin Date: July 2, 2021Last edited: July 28, 2021