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B1: Impaired Water Bodies Improvement*

About This Project

This project helps the District meet surface water quality standards and reduces 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 methylmercury formation, and 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.


*This project was voter approved as part of the Safe, Clean Water and Natural Flood Protection Program.

Calero Reservoir Oxygenation System
On Target
Start FY 2014 / Finish FY 2028
Safe, Clean Water Fund ($27.4 million)
News and UpdatesNews and Updates
Reports and DocumentsReports and Documents
Environmental and Community BenefitsEnvironmental and Community Benefits
History and BackgroundHistory and Background
News & Updates

The project is on schedule and within budget.

Treatment Systems in Reservoirs

  • Oxygenation systems began operating in late February and March due to early season stratification of the reservoirs . Stratification occurs in the summer when the reservoirs have distinct layers based on temperature. The bottom layer (hypolimnion) is where mercury is converted to methylmercury under anoxic (no oxygen) conditions. 

  • Performing monthly to twice monthly water quality monitoring at Almaden, Guadalupe, Calero, and Stevens Creek reservoirs and Lake Almaden.

  • Coordinating with project partners (County of Santa Clara, Midpeninsula Regional Open Space District, and Guadalupe Rubbish Company) and the San Francisco Regional Water Quality Control Board to plan the second 5-year phase of the Coordinated Monitoring Program for the Guadalupe River Mercury TMDL project. For more information on the Guadalupe Mercury TMDL project, please see here. A cost share agreement was approved by the District Board on January 23, 2018 ( and a consultant contract to perform the next phase of monitoring is under development.

  • Continued services for scientific review of mercury data relating to oxygenation system efficacy and reduction of methylmercury in fish.

  • Shared knowledge and lessons learned with international visitors.  Please see here.

  • Submitted a report on the mercury studies to the San Francisco Regional Water Quality Control Board.

  • Participating in the State Boards Program for Mercury in Reservoirs.


Pollution prevention activities

  • Updated the B1 Prioritization Plan with revised analysis of impaired water bodies. 

  • Pollution Prevention Activity #1:
    Accumulation Point Mapping (Guadalupe River): trash was cleaned up on the FY16 accumulation map, removing approximately 78 cubic yards of trash. Cleaned up about 2 cubic yards of trash raft material on September 13, 2017. Guadalupe River Trash Mapping: Updated the Guadalupe River Trash Accumulation Point GIS mapping with 2017 data

  • Pollution Prevention Activity #2:
    Funding a City of San José Park Ranger: Continued financial support of a Park Ranger to monitor and discourage the re-establishment of encampments along Guadalupe River and Coyote Creek.

  • Pollution Prevention Activity #3:
    Coyote Creek Trash Mapping: Began planning for Coyote Creek Trash Accumulation Point GIS mapping. See the Coyote Creek Trash Accumulation Point GIS map here.

  • Pollution Prevention Activity #4:
    Completed first phase of angler survey at mercury impaired reservoirs and lakes to help inform outreach and signage.   For an interim report, please see here.



Updated April 2018 

For more information:



Example of a trash accumulation point on Coyote Creek between highway 880 and E. Brokaw Road, located on 1/29/2018.


Reports & Documents

Pollution prevention activities

Environmental & Community Benefits

Key Performance Indicators for the Safe, Clean Water Program 

  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.


  • 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

Geographic Area of Benefit 


History & Background

About the Safe, Clean Water and Natural Flood Protection Program

In November 2012 the voters of Santa Clara County overwhelmingly approved Measure B, the Safe, Clean Water and Natural Flood Protection Program, as a countywide special parcel tax for 15 years with a sunset date of June 30, 2028. This Program replaced the Clean, Safe Creeks and Natural Flood Protection Plan, which voters approved in November 2000.

The Safe, Clean Water Program was developed with input from more than 16,000 residents and stakeholders and was created to match the community’s needs and values. The voters of Santa Clara County identified five priorities:

Priority A: Ensure a Safe, Reliable Water Supply

Priority B: Reduce Toxins, Hazards and Contaminants in our Waterways

Priority C: Protect our Water Supply from Earthquakes and Natural Disasters

Priority D: Restore Wildlife Habitat and Provide Open Space

Priority E: Provide Flood Protection to Homes, Businesses, Schools and Highways

Other: Six projects from the Clean, Safe, Creeks Plan have been carried forward into the Safe, Clean Water Program.  

Each year, the District prepares a report providing a progress update for each of these Program priorities, along with fiscal year accomplishments.

To ensure transparency and accountability to the voters, the ballot measure also created an Independent Monitoring Committee, appointed by the Santa Clara Valley Water District Board of Directors. The  Independent Monitoring Committee annually reviews the Program’s progress to ensure the outcomes are achieved in a cost-efficient manner and reports its findings to the Board.

In addition, the Program requires three independent audits, the first of which was conducted in FY 2017.

View the Safe, Clean Water Program’s annual reports, annual IMC audit reports, and independent audits, including a staff response, on the District website.