The use of high-resolution LiDAR, and the products derived from it, allow for levee anatomy to be captured for the surveyed area. The resulting data is a catalog of precise levee location and components. This data can further be used for levee maintenance and management, flood modeling and prediction, as well as levee inventories. In the Delta Anatomy Mapping Project all levee anatomies were delineated using slope grids built from available LIDAR data points. LIDAR data points were converted to digital elevation models and subsequently into slope grids. Thresholds were identified that capture the levee crown, levee landside, levee waterside, ramps and toe ditches. Visual interpretations of slope thresholds were used in conjunction with heads-up digitizing to maintain smooth boundaries at a scale of 1:550. The delineation thresholds were derived from a combination of mapping scale, slope grid resolution and slope thresholds used for each anatomy classification. All anatomy has gone through an internal quality control process to ensure a minimum accuracy of +/- 3 feet. Anatomy was further reviewed and tested by DWR for compliance with an interpretive mapping standard of 80% accuracy. This data depicts the levee anatomy at the time of the LiDAR survey (2007) and are only accurate for that time. Users should be aware that temporal changes may have occurred since this data set was created and some parts of this data may no longer represent actual surface conditions. This version created by mapping from the 2007 Delta LIDAR. The associated data are considered DWR enterprise GIS data, which meet all appropriate requirements of the DWR Spatial Data Standards, specifically the DWR Spatial Data Standard version 3.1, dated September 11, 2019. DWR makes no warranties or guarantees — either expressed or implied — as to the completeness, accuracy, or correctness of the data. DWR neither accepts nor assumes liability arising from or for any incorrect, incomplete, or misleading subject data. Comments, problems, improvements, updates, or suggestions should be sent to GIS@water.ca.gov

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Department of Water Resources Hydrologic Region boundaries derived from i03_DAU_county_cnty2018.

The USGS National Hydrography Dataset (NHD) Downloadable Data Collection from The National Map (TNM) is a comprehensive set of digital spatial data that encodes information about naturally occurring and constructed bodies of surface water (lakes, ponds, and reservoirs), paths through which water flows (canals, ditches, streams, and rivers), and related entities such as point features (springs, wells, stream gages, and dams). The information encoded about these features includes classification and other characteristics, delineation, geographic name, position and related measures, a "reach code" through which other information can be related to the NHD, and the direction of water flow. The network of reach codes delineating water and transported material flow allows users to trace movement in upstream and downstream directions. In addition to this geographic information, the dataset contains metadata that supports the exchange of future updates and improvements to the data. The NHD supports many applications, such as making maps, geocoding observations, flow modeling, data maintenance, and stewardship. For additional information on NHD, go to https://www.usgs.gov/core-science-systems/ngp/national-hydrography. DWR was the steward for NHD and Watershed Boundary Dataset (WBD) in California. We worked with other organizations to edit and improve NHD and WBD, using the business rules for California. California's NHD improvements were sent to USGS for incorporation into the national database. The most up-to-date products are accessible from the USGS website. Please note that the California portion of the National Hydrography Dataset is appropriate for use at the 1:24,000 scale. For additional derivative products and resources, including the major features in geopackage format, please go to this page: https://data.cnra.ca.gov/dataset/nhd-major-features Archives of previous statewide extracts of the NHD going back to 2018 may be found at https://data.cnra.ca.gov/dataset/nhd-archive. In September 2022, USGS officially notified DWR that the NHD would become static as USGS resources will be devoted to the transition to the new 3D Hydrography Program (3DHP). 3DHP will consist of LiDAR-derived hydrography at a higher resolution than NHD. Upon completion, 3DHP data will be easier to maintain, based on a modern data model and architecture, and better meet the requirements of users that were documented in the Hydrography Requirements and Benefits Study (2016). The initial releases of 3DHP will be the NHD data cross-walked into the 3DHP data model. It will take several years for the 3DHP to be built out for California. Please refer to the resources on this page for more information. The FINAL,STATIC version of the National Hydrography Dataset for California was published for download by USGS on December 27, 2023. This dataset can no longer be edited by the state stewards. The first public release of the 3D Hydrography Program map service may be accessed at https://hydro.nationalmap.gov/arcgis/rest/services/3DHP_all/MapServer. Questions about the California stewardship of these datasets may be directed to nhd_stewardship@water.ca.gov.

This dataset depicts change in groundwater level at selected monitoring locations (wells) between two specified years, by season. Change values represent change in groundwater level (elevation) by year and season (fall or spring). Other information on the monitoring location is also included. Positive values indicate groundwater has risen (groundwater surface elevation has increased) from the early year to the late year, while negative values indicate groundwater level surface has fallen (decreased in elevation ) from the early year to the late year. Water level monitoring locations and measurements used are selected based on measurement date and well construction information, where available, and approximate groundwater levels in the unconfined to uppermost semi-confined aquifers. For more information on this service, please contact gis@water.ca.gov

This dataset depicts groundwater level (expressed as depth below ground surface) at selected monitoring locations (wells), by season and year. Other information on the monitoring location is also included. Water level monitoring locations and measurements used are selected based on measurement date and well construction information, where available, and approximate groundwater levels in the unconfined to uppermost semi-confined aquifers.