Coastal A-Z [return to Table of Contents] TMDLs and Impaired Water Bodies The following was adapted from information taken from the web site of California's State Water Resources Control Board (SWRCB) ­ http://www.swrcb.ca.gov/tmdl Water quality control agencies in other states should have similar programs. Section 303(d) of the federal Clean Water Act (CWA), requires States to identify waters that do not meet water quality standards (called "impaired water bodies") after applying effluent limits for point sources other than publicly-owned treatment works (POTWs) that are based on the best practicable control technology currently available and effluent limits for POTWs based on secondary treatment. States are then required to prioritize waters/watersheds for total maximum daily loads (TMDL) development (see below). States are to compile this information in a list and submit the list to USEPA for review and approval. This list is known as the 303(d) list of impaired waters (303(d) list). The State Water Resources Control Board (SWRCB) and Regional Water Quality Control Boards (RWQCBs) have ongoing efforts to monitor and assess water quality, to prepare the Section 303(d) list, and to develop TMDLs. It is interesting to note that the Clean Water Act does not require the implementation of TMDLs, only the development of the document. A new federal regulation, established in August 2000 and set to become effective in October 2001, requires that implementation plans be developed along with the TMDLs. Ambient Monitoring The SWRCB is developing a new program to monitor the quality of the State's Waters. The Surface Water Ambient Monitoring Program (SWAMP) will assess impacts on beneficial uses, the locations of polluted sites, the areal extent of pollution, and trends in water quality. Section 303(d) List The State's most recent 303(d) list was approved in 1998. California's current Section 303(d) list contains 509 water bodies, many for multiple pollutants. The list is periodically updated. Recently (April 2002) the SWRCB released a draft proposal to add 195 creeks, lakes, and stretches of the ocean to the list and remove 70 locations. Removal from the list does not necessarily mean that the waters are no longer impaired ­ it may only mean that plans to limit pollution (TMDL plans and allocations) have been completed. Priorities (high, medium, low) are assigned to each pollutant causing impairment at each listed water body, and TMDLs are developed for each pollutant according to a schedule shown on the 303(d) list. Total Maximum Daily Loads (TMDLs) TMDLs are documents that describe a specific water quality attainment strategy for a water body and related impairment identified on the 303(d) list. TMDLs may include more than one water body and more than one pollutant. The TMDL defines specific measurable features that describe attainment of the relevant water quality standards. TMDLs include a description of the total allowable level of the pollutant(s) in question and allocation of allowable loads to individual sources or groups of sources of the pollutant(s) of concern. Typical categories of pollutants include metals, pesticides, pathogens (bacteria and viruses or sometimes specified as "high coliform count"), nutrients, priority organics, sedimentation/siltation, salinity/TDS/chlorides, and trash.