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85th and 95th Percentile Rainfall

These layers represent the spatial distribution of the 85th and 95th percentile, 24-hour rainfall within the County of Los Angeles.

Rainfall gages throughout the County were selected based on spatial distribution and rainfall record length to determine the 85th and 95th percentile, 24-hour rainfall. The 85th and 95th percentile, 24-hour rainfall can be used to […]

Public GIS Mapping Services

We are making a number of our GIS data layers available as public mapping services based upon ESRI’s ArcGIS Server technologies at this URL (http://public.gis.lacounty.gov/public/rest/services). More details on each service will follow as we have the time to describe them, but generally they include GIS data that can be downloaded from […]

Active Wells

Abstract:

The Los Angeles County Department of 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:

 

The State of California Department of […]

NOAA Data Portals

I was recently made aware of a couple of sites where NOAA makes data available.

West Coast Ocean Data Portal, which hosts data related to the oceans on the west coast:

 

 

 

 

 

 

NOAA Digital Coast Data Registry, which is a national site (but you […]

Stormwater Catchment Areas

Abstract: This GIS layer was created to delineate catchment areas for Municipal Separate Storm Sewer System (MS4) outfalls under the Los Angeles County Flood Control District (LACFCD) jurisdiction pursuant to a 2012 National Pollutant Discharge Elimination System (NPDES) permit.

 

Description: The data is a compilation of storm drain hydrology studies completed by the […]

Los Angeles County Storm Drain System

Sample Channels, Gravity Mains, Catch Basins, etc.

The Los Angeles County Storm Drain System is a geometric network model representing the storm drain infrastructure within Los Angeles County. The long term goal of this network […]

California Spatial Information Library (CaSIL)

The Cal-Atlas site facilitates the coordinated and sustainable development, maintenance, licensing and sharing of geospatial data and web map services by California government agencies, partners and stakeholders. California government agencies work with the California GIS Council, regional GIS collaboratives and the broader California GIS community to define the data architecture, systems, standards, agreements and processes […]

Watershed Boundaries

This dataset contains watershed boundaries for watersheds covering Los Angeles County.

This dataset was downloaded, extracted and prepared from the National Hydrography Dataset. The NHD is a comprehensive effort by the US Geological Survey to manage and maintain a comprehensive, high quality, nationwide dataset for GIS mapping and analysis of water features and […]

Hydrologic Points

This dataset contains hydologic points (gaging stations, gates, rock features, springs, water intakes, wells, waterfalls, reservoir points) in LA County.

This dataset was downloaded, extracted and prepared from the National Hydrography Dataset. The NHD is a comprehensive effort by the US Geological Survey to manage and maintain a comprehensive, high quality, nationwide dataset […]

Lakes & Reservoirs

This dataset contains lakes & reservoirs in LA County.

This dataset was downloaded, extracted and prepared from the National Hydrography Dataset. The NHD is a comprehensive effort by the US Geological Survey to manage and maintain a comprehensive, high quality, nationwide dataset for GIS mapping and analysis of water features and conveyance. While […]

Rivers, Streams, Water Conveyance (pipelines, aqueducts)

This dataset contains rivers, streams, and water conveyance mechanisms (pipelines, aqueducts).

This dataset was downloaded, extracted and prepared from the National Hydrography Dataset. The NHD is a comprehensive effort by the US Geological Survey to manage and maintain a comprehensive, high quality, nationwide dataset for GIS mapping and analysis of water features and […]

Debris Potential Areas

Abstract: Los Angeles Basin, Santa Clara River Basin, and Antelope Valley are divided into zones that yield similar volumes of sediment under similar conditions. These are called Debris Potential Area (DPA) zones. Sediment production from a watershed is a rate at which sediment passes a particular point, usually expressed as cubic yards per square […]

Seawater Barriers

Abstract: The Los Angeles County Department of Public Works operates and maintains three seawater barriers along Los Angeles County’s coastline. Often unnoticed because of their underground nature, these facilities serve as Los Angeles basin’s fresh water sentinels. They protect a significant portion of the area’s drinking water supply from ocean water, which constantly attempts […]

Ground Water Basins

Abstract: This data was acquired from the Integrated Water Resources Information System (IWRIS), hosted by the California Department of Water Resources(DWR). The Bulletin 118 Groundwater Basins shapefile was downloaded, projected to the CCS83 Zone 5 (ftUS) Map projection and clipped to the Los Angeles County Boundary for internal Los Angeles County use.It is […]

Stream Gage Locations

Abstract: Stream Gage locations

Purpose: General mapping use

Download Data

Direction of flow within Sub Watersheds

Abstract: Direction of water flow between sub watersheds (or watershed sub basins). Download Data

Soil Types

Abstract: This layer was created to represent soil types in Los Angeles County. Polygons were derived from scanned soil maps. Attributes include a soil number (2-180), corresponding to runoff coefficient values in a Hydrology Manual, provided by the Los Angeles County Department of Public Works, Water Resources Division.

Purpose: For use in DPW’s Modified […]

Spreading Grounds

Abstract: This layer was created to represent stormwater spreading grounds operated by the Los Angeles County Department of Public Works. These spreading grounds are selected and managed for capturing as much water as possible during storms. Locations were chosen with permeable soil formations to enable recharging of underground aquifers. An estimated 30 to 40 […]

Dams and Debris Basins – Point Locations

Abstract:

Debris Basins are key components of the Los Angeles County Flood Control District’s (LACFCD) flood control system. Typically located at the mouths of canyons, debris basins capture sediment, gravel, boulders, and vegetative debris that are washed out of the canyons during storms, protecting lower lying communities from possible flooding and property damage. Due […]