Total Maximum Daily Load (TMDL) is established at the level necessary to implement the applicable water quality standards. A TMDL requires that all sources of pollution and all aspects of a watershed's drainage system be reviewed. TMDLs in California are developed either by RWQCBs or by USEPA. TMDLs developed by RWQCBs are designed as Basin Plan amendments and include implementation provisions. TMDLs developed by USEPA typically contain the total load and load allocations required by Section 303(d), but do not contain comprehensive implementation provisions. This stems from the fact that USEPA authorities related to implementation of nonpoint source pollution control measures are generally limited to education and outreach as provided by Clean Water Act (CWA) Section 319. TMDLs are currently required for all waters and pollutants on the 303(d) list. TMDLs must consider and include allocations to both point sources and nonpoint sources of listed pollutants. There also can be multiple TMDLs on a particular water body, or there can be one TMDL that addresses numerous pollutants. The basis for grouping is whether or not there can be a common analytical approach to the assessment or a common management response to the impairment. Source: http://www.waterboards.ca.gov/water_issues/programs/tmdl/background.shtml

The applicable TMDL to the County were identified from the corresponding Regional Water Quality Control Boards (RWQCB): http://www.waterboards.ca.gov/water_issues/programs/tmdl/

Then the corresponding TMDL waterbody was extracted from the original statewide 303(d)/TMDL impaired waterbody data created by the State Water Resources Control Board (http://www.waterboards.ca.gov/water_issues/programs/tmdl/integrated2010.shtml).

This data was not used as a stand alone layer for the Stormwater and Water Conservation Tracking Tool for Riverside County. It was incorportated into the Channel lines and Storage Facility Area layers.

Data current as of August 2012

Currency of updates - Bi-Yearly

Expected next update - Yet to be determined