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B1: Impaired Water Bodies Improvement*

About This Project

This project reduces pollutants in streams, reservoirs and groundwater of Santa Clara County by supporting surface water quality pollution prevention activities. These programs address water quality concerns currently identified by local and state regulatory agencies, as well as contaminants of emerging concern. Initiatives under this project are consistent with the Regional Water Quality Control Board (RWQCB) impaired water bodies designation and Total Maximum Daily Loads (TMDLs), which are the maximum amount of a pollutant that a water body can receive and still safely meet water quality standards. Under this project, Valley Water studies and implements methods to reduce methylmercury formation in reservoirs, and helps create and carry out realistic plans to reduce contaminants, such as nutrients, bacteria, pesticides, polychlorinated biphenyls (PCBs) and others, in local creeks and reservoirs.


This project addresses both greenhouse gas (GHG) reduction and climate change adaptation, as reservoirs are a major source of GHG emissions (i.e. methane) during low oxygen conditions. Oxygenation is the current mechanism to control mercury in fish and may reduce methane emissions. Oxygenation can also reduce the formation of harmful algal blooms, which may become more frequent with warmer temperatures.

 

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

Calero Reservoir Oxygenation System
Datapoints
Status
On Target
Location
Countywide
Schedule
Start FY 2022 / Finish FY 2036
Funding
Safe, Clean Water Fund ($32.8 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

KPI #1: Actions to reduce methylmercury in the Guadalupe Watershed

  • Ordinarily, hypolimnetic oxygenation systems (HOS) would be deployed at 4 reservoirs: Almaden, Guadalupe, Calero, and Stevens Creek. Valley Water did not operate oxygenation systems at Guadalupe or Stevens Creek reservoirs in Summer 2021 due to low water levels and concerns for maintaining downstream fish habitat. Oxygenation can increase the temperature of reservoir releases, particularly when storage volume is low. To maintain cold water releases for as long as possible, Valley Water decided to delay oxygenation until drought conditions improve.
  • Valley Water completed monthly water quality monitoring at Almaden, Guadalupe, Calero, and Stevens Creek reservoirs, and Almaden Lake.
  • Valley Water coordinated with project partners (County of Santa Clara, Midpeninsula Regional Open Space District, and Guadalupe Rubbish Disposal Company) and the RWQCB to continue implementation of the second 5-year phase of the Coordinated Monitoring Program for the Guadalupe River Watershed Mercury TMDL project. See documents in the Reports & Documents section of this webpage. For more information on the TMDL project, please see here. Stream fish monitoring scheduled for summer 2021 was delayed after four of six approved monitoring stations were found to be dry or with water temperature exceeding permit thresholds. Fish monitoring will be performed when drought conditions improve.  
  • To better understand the effects of the oxygenation system on Stevens Creek Reservoir discharge and downstream dissolved oxygen, turbidity, and temperature, Valley Water conducted a one-year study starting in June 2020.  Results of the study will help staff optimize operation of the oxygenation system to maximize overall benefits. The study plan can be found here. A project report is currently in progress.
  • Valley Water staff presented its mercury control work to the National Water Quality Monitoring Council (April 2021) and the California Stormwater Quality Association (October 2021). Valley Water collected suspended particulate matter and zooplankton from Almaden, Calero, Guadalupe, and Stevens Creek reservoirs in June 2021. These samples are being analyzed for stable isotopes of nitrogen and carbon, total mercury, and methylmercury as part of Valley Water’s reservoir mercury bioaccumulation study.
  • In April 2021, data were published for Valley Water’s collaborative study with USGS: “The Measurement of Water Column Methylmercury Production Potential Rates in Four Oxygenated Reservoirs of the San Francisco Bay Watershed.”

KPI #2: Plan for surface water quality improvement activities

  • The Prioritization and Implementation of Pollution Prevention and Reduction Activities Plan to Address Impaired Water Bodies in Santa Clara County (Prioritization Plan), is periodically reviewed following the San Francisco Regional Water Quality Control Board’s (Water Board) Triennial Review of the Basin Plan, which sets priorities for projects to address various impairment types.  Valley Water uses the Water Board’s Triennial Review and its list of impaired water bodies to evaluate potential projects in water bodies within our jurisdiction. The Water Board has just completed the Triennial Review and Valley Water will begin updating the prioritization plan in summer 2022. Since Water Board priorities change over time as impairments are addressed and new problems are identified, the Prioritization Plan is a living document that is updated according to changing Water Board priorities

KPI #3: Implementation of surface water quality improvement activities

  • Surface Water Quality Improvement Activity #1: Accumulation Point Mapping and Remove (Guadalupe River)
    Valley Water and City of San José staff will begin visual trash assessments of Guadalupe River in November 2021
  • Surface Water Quality Improvement Activity #2: Accumulation Point Mapping and Removal (Coyote Creek
    Valley Water and City of San Jose staff completed visual trash assessments along Coyote Creek in October 2021. See the Coyote Creek and Guadalupe River Trash Accumulation Point GIS map here.
  • Surface Water Quality Improvement Activity #3: Reservoir Greenhouse Gas Emission Study
    Valley Water entered a collaborative agreement with University of California, Davis to study greenhouse gas emissions from the surfaces of Chesbro, Stevens Creek, and Uvas Reservoirs. During this year-long study, researchers will quantify the seasonal and spatial variation of reservoir greenhouse gas fluxes. This information will be incorporated Valley Water’s Climate Change Action Plan to help achieve carbon neutrality.  In July 2021, researchers conducted sonar-like hydroacoustic surveys and measured greenhouse gas flux rates at all three reservoirs. Monthly 24-hour greenhouse gas flux monitoring events in Uvas Reservoir began in February 2021 and will continue until December 2021.
  • Surface Water Quality Improvement Activity #4 Unhoused Best Practices
    Valley Water is collaborating with Santa Clara County Parks and the Cities of Morgan Hill and Gilroy to provide vouchers for responsible disposal of wastewater for unhoused individuals living in RV’s. Vouchers can be used for free RV waste disposal at Coyote Lake and Mt. Madonna County Parks. Waste disposal vouchers will be distributed to unhoused individuals in FY22 by Morgan Hill and Gilroy police department task forces.

Updated December 2021

For more information:

 

 

 

 

 

 

 

Reports & Documents

No documents

Environmental & Community Benefits

FY22-36 Key Performance Indicators for the Safe, Clean Water Program 

  1. Investigate, develop, and implement actions to reduce methylmercury in fish and other organisms in the Guadalupe River Watershed.

  2. Prepare and update a plan for the prioritization of surface water quality improvement activities, such as addressing trash and other pollutants.

  3. Implement at least two (2) priority surface water quality improvement activities identified in the plan per 5-year implementation period.

Benefits

  • Reduces contaminants in streams and reservoirs

  • Improves water quality, including water slated for drinking water treatment plants

  • Increases understanding of mercury cycling in reservoirs to develop strategies that reduce toxic methylmercury in fish consumed by people and wildlife

  • Increases the scientific understanding of environmental pollutants to assist in developing actions to manage them

  • Supports regulatory compliance with surface water quality standards for local creeks and reservoirs

  • Addresses climate change

Geographic Area of Benefit 

Countywide 

History & Background

About the Safe, Clean Water and Natural Flood Protection Program

In November 2020, voters in Santa Clara County overwhelmingly approved Measure S, a renewal of Valley Water’s Safe, Clean Water and Natural Flood Protection Program.

The program was first passed by voters in 2000 as the Clean, Safe Creeks and Natural Flood Protection Plan, then again in 2012 as the Safe, Clean Water and Natural Flood Protection Program. The renewal of the Safe, Clean Water Program will continue to provide approximately $47 million annually for local projects that deliver safe, clean water, natural flood protection, and environmental stewardship to all the communities we serve in Santa Clara County.

While evaluating ways to improve the 2012 program, Valley Water gathered feedback from more than 21,000 community members. That helped Valley Water create the six priorities for the renewed Safe, Clean Water Program, which are:

  • Priority A: Ensure a Safe, Reliable Water Supply
  • Priority B: Reduce Toxins, Hazards and Contaminants in our Waterways
  • Priority C: Protect our Water Supply and Dams from Earthquakes and Other Natural Disasters
  • Priority D: Restore Wildlife Habitat and Provide Open Space
  • Priority E: Provide Flood Protection to Homes, Businesses, Schools, Streets and Highways
  • Priority F: Support Public Health and Public Safety for Our Community

Each year, Valley Water 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. Additionally, the IMC also reviews each proposed 5-year implementation plan prior to its submittal for Board approval.

In addition, the program requires three independent audits.

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