Every 2 years, the CA Water Resources Control Board revisits a “working list” of polluted rivers to help establish what is polluting our waterways and why.

Needless to say, the Calaveras River was included in the ever expanding list of polluted waterways in thier 2010 report.

They investigated the river all the way from New Hogan through Stockton, and developed a list of pollutants that will be included on the EPA’s “303(d) list”, which means that water quality standards have been exceeded and the indicated pollutant contributes to or causes the problem.

Here’s a basic list of pollutants they found in the Calaveras River from New Hogan all the way to Stockton  that are exceeding standards (Note: The lion’s share of the pollutants were found in the Stockton Diverting Canal to the San Joaquin River, and in parts of  the easter portion of the Delta waterways):

  • Organic Enrichment/ low dissolved oxygen (urban runoff/ storm sewers)
  • Diazinon (agriculture)
  • Mercury (resource extraction)
  • Chlorpyrifos (agriculture)
  • Pathogens (urban runoff/ storm sewers)
Click here to read the full list of pollutants and search a map on the CA State Water Resources Board web page.