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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.

KPI #1: Treatment Systems in Reservoirs and Mercury Studies

  • As of September 2018, all the oxygenation systems have been turned off for the wet season when reservoirs are no longer stratified. Stratification occurs during the dry season when the reservoirs separate into distinct layers based on temperature. The bottom layer (hypolimnion) is one of the primary locations where mercury is converted to methylmercury under anoxic (no oxygen) conditions. The oxygen diffuser line in Calero Reservoir was damaged, likely by a recreational boater’s anchor line. Therefore, the system was not operated from April 24-June 4, 2018 as repairs were being coordinated.  

  • The Santa Clara Valley Water District (District) performs twice-monthly water quality monitoring at Almaden, Guadalupe, Calero, and Stevens Creek reservoirs, and Lake Almaden when the reservoirs and lake are stratified (monthly the rest of the year).

  • The District coordinated with project partners (County of Santa Clara, Midpeninsula Regional Open Space District, and Guadalupe Rubbish Disposal Company) and the San Francisco Bay Regional Water Quality Control Board (Regional Board) to plan the second 5-year phase of the Coordinated Monitoring Program for the Guadalupe River Watershed Mercury TMDL project. For more information on the TMDL project, please see here. The District Board approved a cost share agreement on January 23, 2018 ( The partners selected Tetra Tech to perform the required monitoring. The Regional Board approved the sampling plan developed for the Coordinated Monitoring Program.

  • The District presented results of the its methylmercury control studies to the Association of Clean Water Agencies (ACWA) Regulatory Forum. District staff co-authored a scientific paper investigating methods to control the release of toxic mercury from submerged sediments.

  • The District submitted a report on the mercury studies to the Regional Board. The progress report and accompanying fish assemblage report can be found here. The report was well-received by the Regional Board. The Regional Board approved the District’s suggested sampling changes, which will save time and resources for the mercury sampling program.

  • Findings of the District’s technical studies will inform the implementation plan of the upcoming Statewide Mercury Program for reservoirs that is being developed by the State Water Resources Control Board (SWRCB). The District has actively participated in the statewide effort.

  • The District provided tours of the Calero Reservoir to the Safe, Clean Water Program's Independent Monitoring Committee, and to groups of teachers to provide information on the mercury in reservoirs program.


KPI #2 Prioritization Plan

  • The District developed the Prioritization and Implementation of Pollution Prevention and Reduction Activities Plan to Address Impaired Water Bodies in Santa Clara County in January 2015 and updated it in June 2017 with revised analysis of impaired water bodies. 


KPI #3: Pollution prevention activities

  • Pollution Prevention Activity #1: Accumulation Point Mapping and Removal (Guadalupe River)
    In April and May 2018, the District removed 6 cubic yards of trash from Los Gatos Creek and 8 cubic yards from Guadalupe River under a Memorandum of Agreement with the City of San José. City and District staff are mapping trash accumulation points in the fall of 2018.

  • Pollution Prevention Activity #2: Funding a City of San José Park Ranger to monitor and discourage the re-establishment of encampments along Guadalupe River and Coyote Creek
    The District does not have a current agreement to fund San Jose Park Rangers due to staff shortages in the City of San José's Parks and Recreation department. The District is actively participating in the Park Ranger Working Group with the City of San José. The District funds a California Department of Fish and Wildlife warden position; however, the position is currently not filled.

  • Pollution Prevention Activity #3: Coyote Creek Trash Mapping and Removal
    The District began the Coyote Creek Trash Accumulation Point GIS mapping in FY18. In March and April of 2018, the District removed 38 cubic yards of trash from 3 raft locations on Coyote Creek under the Memorandum of Agreement with the City of San José. City and District staff are mapping trash accumulation points in the fall of 2018. See the Coyote and Guadalupe Creek Trash Accumulation Point GIS map here.

  • Pollution Prevention Activity #4: Angler Survey 
    The District completed the second phase of the Santa Clara County Reservoir Angler Survey at mercury impaired reservoirs and lakes to help inform future outreach and signage. A final report is being developed. For an interim report, please see here.



Updated June 2018 

For more information:



Example of a trash accumulation point on Coyote Creek between Highway 880 and E. Brokaw Road (January 29, 2018). 



Photos from Guadalupe Trash Raft Clean-Up (September 13, 2017). 







Reports & Documents

Mercury studies

District studies

Coordinated monitoring program

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.