Crowley Reservoir - Nutrients
H.U. 603.10

Crowley Lake is classified as a reservoir and is part of the Long Hydrologic Area (HU No.603.10) within the Owens Hydrologic Unit (HU No. 603.00, Figure 1). The designated beneficial uses for Crowley Lake are listed in the Basin Plan (LRWQCB, 1995) and include the following:

  • Municipal and Domestic Supply (MUN)
  • Agricultural Supply (AGR)
  • Navigation (NAV)
  • Hydropower Generation (POW)
  • Water Contact Recreation (REC-1)
  • Non-Contact Water Recreation (REC-2)
  • Commercial and Sport fishing (COMM)
  • Cold Freshwater Habitat (COLD)
  • Wildlife Habitat (WILD)
  • Spawning, Reproduction, and Development (SPAWN)

Since Crowley Lake is the largest reservoir in the LADWP aqueduct system and provides water for municipal and domestic supply, downstream irrigation, and hydroelectric power generation, the MUN, AGR, and POW beneficial uses are being attained. Crowley Lake is a very popular fishing and boating venue. While seasonal algal blooms may have occasional negative effects on boating and swimming, Board Staff believe that algal blooms are sufficiently sporadic in time and extent such that they do not significantly impair the recreation and fishing beneficial uses. This is supported by results of a survey conducted as part of the Mono Basin Environmental Impact Report (Jones & Stokes, 1993), which showed that 188 of 243 respondents were “generally satisfied” or “very satisfied” with Crowley Lake recreation opportunities. Therefore, the information suggests that NAV, REC-1, REC-2, and COMM beneficial uses are met.

The occurrence of elevated ammonia and depressed dissolved oxygen concentrations are associated with the natural eutrophic condition of Crowley Lake. Therefore, Board Staff recommend the preparation of site-specific objectives or other basin planning amendments that recognize and account for natural conditions. We do not anticipate preparing a TMDL for these constituents for Crowley Lake.


Available Documents