Clear Creek and Hernandez Reservoir Mercury TMDL


Problem Statement - Data from a number of sources indicate total mercury levels in water in Clear Creek ranging from less than 0.1 μg/L up to 1.5 μg/L. The appropriate numeric objective for total mercury in water is 0.050 μg/L (as expressed in the California Toxics Rule), so Clear Creek is impaired by mercury. The available data indicate that the San Benito River is currently meeting water quality objectives for mercury. The data also indicate that Hernandez Reservoir is currently meeting water column objectives for mercury (1998 data), but the most recent fish tissue from the reservoir (which are older samples from 1995) contains mercury at levels averaging about 0.6 mg mercury/kg tissue.



Status and Public Notices

  • Status: Fully approved and effective.
  • Report Card - November 2017
  • Public Notice: None at this time.

Approval status

  • Central Coast Water Board
    - adopted March 19, 2004.
  • US Environmental Protection Agency
    - approved June 21, 2004, which is the effective date.