Cypress Mountain Road Sediment Reduction

Contaminated segment of Las Tablas Creek
Contaminated segment of Las Tablas Creek

Pacific Watershed Associates was retained to design a sediment reduction plan for a four mile road segment capped with mercury laced mine tailings

County of San Luis Obispo
San Luis Obispo County, California

The legacy of mercury mining at the Buena Vista and Klau mines in San Luis Obispo county manifests itself as severe mercury contamination of the Las Tablas creek.  Las Tablas creek drains to the Nacimiento Reservoir where high mercury levels have resulted in the mines being designated as EPA superfund sites.  Compounding contamination problems is the Cypress Mountain road which has, for the past decade, been rocked with mercury laden mine tailings.

In collaboration with San Luis Obispo County and the Environmental Protection Agency, Pacific Watershed Associates was contracted to develop a plan to eliminate contaminated road generated sediment input to the Las Tablas watershed.  

Specifically, Pacific Watershed Associates:

  • Developed a new road drainage infrastructure configuration designed to completely eliminate contaminated road runoff from discharging into the stream network.
  • Worked with county engineers to develop a road shaping plan consistent with both sediment elimination and desired safety conditions.
  • Cultivated a working relationship with local landowners to inform them of the project goals and to garner pertinent information from them. 
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