The location of the ALERT(Automatic Local Evaluation in Real Time)/Automatic rain gages; These sites use tipping buckets with real-time data telemetry and/or electronic data loggers to indicate rainfall totals and intensities. Data collected is used for calculating rainfall totals and intensities.

Catch basins collect urban runoff from gutters

Based on City Annexations
This layer is used for locating past and present legal city boundaries and for retrieving annexation records. Overlapping polygons indicate territories that transferred between cities. This layer’s URL field can be used for retrieving recorded city annexation documents online.

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 to migrate into existing aquifers. Treated imported and reclaimed water is injected deep into the underground aquifers to block this inland migration of saltwater.

Point layer of street lights in Los Angeles County.Purpose:
This data is used for maintaining inventory of street lights by Traffic and Lighting, a Division of the Los Angeles County Department of Public Works.

The Consolidated Sewer Maintenance District (CSMD) of Los Angeles County is administered by the County of Los Angeles Department of Public Works (DPW).

Direction of water flow between sub watersheds (or watershed sub basins).

Boundaries of sub watersheds or watershed sub areas. Original areas were drawn on U.S.G.S. 7 ½ minute, 1:24,000 scale topo quad sheets by Hydraulic Water Conservation Division. Digitized into ComputerVision CADDS4 by Environmental Programs Division (EPD). Converted to Atlas GIS Atlas Graphic Format (.agf) by EPD. Cleaned up, topology built, downstream connectivity developed in Atlas GIS. Converted to ArcView Shape (.shp) by EPD.

Watershed Management Area. Based on sub-watershed boundaries, which were digitized by Public Works from USGS quads.

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 percent of the water used in the County is pumped from groundwater supplies.