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B1: Impaired Water Bodies Improvement

This project helps the district meet surface water quality standards and reduce pollutants in streams, groundwater, lakes and reservoirs. Efforts are carried out in compliance with the Regional Water Quality Control Board (RWQCB) Total Maximum Daily Loads (TMDLs) standards as they continue to evolve (TMDLs are the maximum amount of a pollutant that a water body can receive and still safely meet water quality standards). Under this project the district employs treatment systems in reservoirs to reduce methylation of mercury, and also helps create realistic plans and expectations for reducing contaminant loads by engaging in the regulatory development process with the RWQCB for new and emerging contaminants.


  • Reduces contamination in creeks and reservoirs
  • Improves water quality, including water going to drinking water treatment plants
  • Reduces mercury in reservoirs to prevent its entry into the food web
  • Improves fisheries by reducing mercury contamination
  • Supports regulatory compliance of TMDL standards affecting District operations

Project Status

(As of June 2017)

  • The project is on schedule and within budget.

Treatment Systems in Reservoirs

  • Maintaining and servicing oxygenation systems currently off line during winter months when reservoirs are not stratified.
  • Monitoring water quality at four reservoirs and Lake Almaden.
  • Coordinating with partners and the Regional Water Quality Control Board on the Coordinated Monitoring Plan five year report. For more information on the Guadalupe Mercury TMDL project, please see here
  • Obtained services for scientific review of mercury data relating to oxygenation system efficacy and reduction of methyl mercury in fish.
  • Prepared abstract on mercury monitoring which was accepted for the International Conference on Mercury as a Global Pollutant.

Prioritization plan and pollution prevention activities

  • Updated the prioritization plan with new information on impaired water bodies. 
  • Pollution Prevention Activity #2: Funding a City of San Jose Park Ranger – continued support of a Park Ranger to monitor and discourage the re-establishment of encampments along Guadalupe River and Coyote Creek 
  • Pollution Prevention Activity #3: Planning for update to Guadalupe River Trash Accumulation Point GIS mapping 
  • Pollution Prevention Activity #4: Planning for Coyote Creek Trash Accumulation Point GIS mapping

Key Performance Indicators

  1. Operate and maintain existing treatment systems in 4 reservoirs to remediate regulated contaminants, including mercury
  2. Prepare plan for the prioritization of pollution prevention and reduction activities
  3. Implement priority pollution prevention and reduction activities identified in the plan in 10 creeks

Prioity B-200

Project Information

Project Start FY 2014
Project Finish FY 2028
Safe Clean Water
Program funding
 $25.1 M**

(2015 Dollars)

**More financial information: 5-Year Implementation Plan, pages: 19-27 

Status Underway
Location Countywide

For more information:

  • Jennifer Castillo (408) 630-3196

 Calero oxygenation station

Calero Dam oxygenation station treatment system

Map of reservoir oxygenation systems [PDF]

Oxygenation system