Source water assessment and protection

The Santa Clara Valley Water District (District) provides treated water from the Penitencia, Rinconada, and Santa Teresa Water Treatment Plants to 7 water retailers in Santa Clara County. The district has a number of sources of water supply for the treatment plants, including the South Bay Aqueduct (SBA), regional and local reservoirs, and groundwater. The majority of the district's treatment source water supply is imported from the SBA, Lake Del Valle, and San Luis Reservoir, which all draw water from the Sacramento - San Joaquin Delta watershed. The district's local water sources include Anderson, Coyote, Calero and Almaden Reservoirs.

The district's source waters are susceptible to potential contamination from a variety of land use practices, such as agricultural and urban runoff, recreational activities, livestock grazing, and residential and industrial development. The imported sources are also at risk from wastewater treatment plant discharges, seawater intrusion, and wildland fires in open space areas. In addition, local sources are also vulnerable to potential contamination from commercial stables and historic mining practices. No contaminant associated with any of these activities has been detected in the district's treated water. The water treatment plants provide multiple barriers for physical removal and disinfection of contaminants.

The district continues to identify potential management practices that could improve source water quality and reduce the impact of potential contaminant sources. The district completes a Watershed Sanitary Survey every five years, as required by the California Department of Health Services (DHS), to examine possible sources of drinking water contamination and recommend how to protect water quality at the source.

The Environmental Protection Agency (EPA) requires all states to establish and implement a Source Water Assessment Program (SWAP) for all public water systems, as promulgated in the 1996 Amendments to the federal Safe Drinking Water Act. In California, the federal SWAP requirement is administered by the Department of Health Services (DHS)(Health and Safety Code Chapter 4, Section 116270). DHS developed the Drinking Water Source Assessment and Protection (DWSAP) Program, to evaluate the vulnerability of water sources to contamination and prioritize activities for protective measures. Assessments of the drinking water sources for the district were completed in 2002.

What is in the district's DWSAP reports?

The South Bay Aqueduct (SBA) DWSAP report was completed by Archibald & Wallberg Consultants, under contract to the district, Alameda County Water District, and Zone 7 Water Agency. The San Luis, Anderson and Calero Reservoir DWSAP reports were prepared by the district, based on a detailed sanitary survey of the watersheds and the district's Comprehensive Reservoir Watershed Management Plan.

Each report presents the possible contaminating activities within the source drainage area, ranked as being of high, medium, or low significance based on the potential of the activity to contribute to water quality challenges at the water treatment plants. The reports also present existing management and protection activities. The following is a summary of the information from each report, characterizing the source of the water supply, and monitoring and source water protection activities.

What are the steps involved in a source water assessment?

• Delineation. The area that contributes water to the well or surface water intake is determined, and source water protection zones are defined.

• Inventory. An inventory of the types of Possible Contaminating Activities (PCAs) within the source protection zones that may affect the water supply is conducted.

• Vulnerability Analysis. A susceptibility analysis of the located potential sources of contamination is conducted. This will alert the public water system to the contaminant sources that have the greatest likelihood of affecting the water supply.

• Reporting. Assessment reports are developed that summarize all the information gained during the assessment. The reports include maps of the source water area, lists of potential sources of contamination, and summaries of the susceptibility analyses. This information is provided to public water systems and made available to the public. You can view the assessment summaries at the links below.

  San Luis DWSAP Assessment Summary
  [pdf 135 KB]

  SBA DWSAP Assessment Summary
  [pdf 155 KB]

  Local DWSAP Assessment Summary
  [pdf 184 KB]

What are the Benefits of Source Water Protection?

• Source water protection safeguards the public health by reducing risks from contamination of drinking water supplies at the source. Source water protection is one barrier in a multi-barrier approach to public health protection. Multiple, and often redundant, treatment processes, distribution system protections, and extensive monitoring are additional measures taken to ensure that no contamination makes its way into the drinking water of Santa Clara County residents.

• Source water protection is cost effective because it is less expensive to treat better quality water. And, the cost of cleaning contaminated source water supplies is much greater than preventing its contamination.

• Source water protection prevents or minimizes contamination of drinking water supplies. By knowing what type, location, and risk of contamination may exist, the district can develop and implement effective, targeted source water protection plans to protect the source water into the future.

• Source water assessments serve as a planning tool to provide water supply information to district managers for planning purposes. Information gained from the source water assessment reports are used in the development of emergency response plans, water infrastructure reliability plans, and municipal land use and development planning and zoning efforts.

What does the district do to protect the County's drinking water sources?

The district engages in many activities to protect, enhance, and restore surface water quality in the County's drinking water supply reservoirs. The information from the DWSAP reports are used to identify and prioritize source water protection activities in local and imported water supplies. The district is working with state and local agencies and the community to identify source water protection measures to prevent contamination of surface water that is used, or may be used in the future, as sources of drinking water. Recent activities include the following.

• The district conducts regular monitoring of all its drinking water sources of supply, to track water quality trends and to respond to anomalies. Regular monitoring for a long list of constituents is also required by the California Department of Health Services, to ensure that the sources meet a basic level of quality prior to treatment. Monitoring schedules outline the specific contaminants and frequency to be sampled in source water systems, and are based on federal and state requirements, past monitoring results, and DWSAP susceptibility assessment determinations.

• The Santa Clara Valley Water District, Alameda County Water District (ACWD), and the Alameda County Water Conservation District Zone 7 (Zone 7) (known jointly as the SBA Contractors), are working along with other area stakeholders on a Proposition 13 CALFED grant-funded project to develop a Watershed Management Program for the SBA system. The program establishes an ongoing forum for watershed stakeholders to discuss management issues, and develops a long-term strategy for SBA system watershed management, including the development and implementation of a Watershed Protection Program Plan. The program will provide heightened awareness in the local community about watershed protection and Best Management Practices (BMPs) through education. The Watershed Management Program will protect local drinking water from identified DWSAP contaminant sources, and raise awareness about watershed management and protection of water resources in the local area.

• At Anderson and Almaden Reservoirs, the district conducts regular monitoring of water quality to ensure that septic systems and waste disposal facilities are operating properly. When problems are identified, the district works with the Department of Environmental Health and the homeowners to resolve the problem.

• At Calero Reservoir, the district is working with the County Parks and Recreation Department and the horse stable operator to develop a management plan and implement Best Management Practices, to reduce contaminated storm water runoff from livestock and manure handling areas. The district regularly monitors water quality, both on-site, and leaving the site, to ensure that management measures are working to protect water quality.

• The district is working with the County Parks and Recreation Department (Parks), the community, and recreational boaters to ensure no contamination events occur from recreational activities on or near the reservoirs. The district and Parks implemented a management strategy in 1998 to eliminate MTBE from the reservoirs. The strategy includes water quality monitoring, and managing the number and type of watercraft allowed on the reservoirs. Now that MTBE is banned from California fuels, the district and Parks are working with the community to modify the program while still ensuring that water quality is protected from other fuel components.

• The district conducts extensive public education and outreach on pollution prevention and stormwater management measures to protect water quality in the County. The district has co-sponsored Ranch and Open-Space Water Quality Management Planning short courses to minimize the impact of cattle grazing on reservoir water quality, and to develop and implement grazing and open space management practices. The district has also co-sponsored Stewardship for Small Acreages, a series of workshops on land management for water quality, and a series of workshops on water quality planning for equine facilities.

• The district is working with the Regional Water Quality Control Board and United Technology Corporation (UTC) to ensure that chemical contamination on UTC's site does not migrate off-site to Anderson Reservoir. The district conducts regular surface water monitoring for perchlorate in Anderson Reservoir and its tributaries to ensure that management and cleanup activities on site are working. The district also closely tracks UTC's extensive on-site cleanup and monitoring activities and suggests additional or alternative strategies when needed.

• The district is working to integrate source water protection in municipal permit requirements, guidelines and standards, zoning, and land use regulations for community projects and activities in reservoir watersheds. The district is working through a stakeholder-driven Water Resources Protection Collaborative to develop guidelines and standards with local planning agencies.

• At Calero and Almaden Reservoirs, the district is working with the Regional Water Quality Control Board and local stakeholders on the development and implementation of mercury remediation efforts.

• The district conducts activities to prevent and reduce pollution to streams, including development of stormwater protection and pollution prevention plans, and implements best management practices for runoff from district facilities and operations, and stream maintenance activities. The district participates with 14 other agencies in the Santa Clara Valley Urban Runoff Pollution Prevention Program, to implement pollution prevention measures, monitoring, and public education and outreach for the Santa Clara Valley . For more information on the Santa Clara Valley Urban Runoff Pollution Prevention Program, visit: www.scvurppp.org

• The district is implementing a land preservation project to preserve and protect the county’s streams, through partnership with property owners, parks and open space districts, land trusts and conservation organizations, to purchase land, development rights, or conservation easements for habitat enhancement, mitigation, and protecting water quality. For more information on the district’s Environmental Land Preservation Project, visit: Environmental Land Preservation Project

• The district operates a 24-hour Incident Response/Pollution Prevention hotline for emergency response planning and reporting of spills and illicit discharges. The Hotline number, 1-888-510-5151, is used for reporting incidents of illegal dumping of trash, debris and hazardous materials in water ways to the Santa Clara Valley Water District. For more information on reporting illegal dumping and discharges to streams please visit this page for phone numbers to report illegal dumping in our waterways . To report stream maintenance problems and service requests, use this online form.

• District maintenance crews provide routine creek cleanup for trash, debris, and sediment that accumulate in district waterways. In addition, the district's Adopt-A-Creek Program coordinates volunteers to organize stream clean-up days. For more information on the Adopt-A-Creek Program visit the Adopt-A-Creek site.

What can the community do to help protect sources of drinking water?

Public participation is important for source water protection. Here are a few things you can do to ensure safe drinking water.

• Read a copy of your local DWSAP report, and learn about issues affecting the sources of your drinking water supply. The California DWSAP documents are available to the public, and are posted on the DHS DWSAP internet site (links below). Get involved in local clean water protection activities. Your local community may need volunteers to help protect water sources.

• Utilize best management measures for cattle grazing and livestock, such as fencing, stock watering, and manure management, to prevent contamination of surface waters that flow to reservoirs and tributaries.

• Implement pollution prevention practices to reduce or eliminate pollutants from stormwater runoff, and minimize impacts of urbanization and development.

• Practice best management practices for agriculture and landscaped areas to reduce or eliminate irrigation runoff, control soil loss and erosion, and prevent contamination from pesticides and fertilizers.

• Know park regulations and obey park rules in recreation, camping and boating areas, to eliminate impact from trash and litter, prevent contamination from pet and human waste, prevent contamination from parking areas and marinas, and prevent forest fires. Stay on approved trails to reduce erosion and destruction of vegetation along reservoir shoreline and streams.

• Conduct regular inspection and maintenance of your septic systems and leach fields

• Minimize impervious areas (paved surfaces and rooftops) to preserve groundwater infiltration and reduce stormwater runoff to source waters and tributaries. Use porous pavement and direct rainwater from rain gutters and downspouts to onsite infiltration.

• Follow community ordinances for grading and construction activities, and implement sediment management measures

• Support the preservation of open-space land and parks for recreation, which also preserves land for source water protection.

Learn more about Source Water Assessment and Protection

EPA's Office of Groundwater and Drinking Water (OGWDW) protects public health by ensuring safe drinking water, and oversees the implementation of the Safe Drinking Water Act. The EPA OGWDW's Source Water Protection Program site provides basic information about the water used for drinking water and the federal, state, and local programs that assess and manage potential public health risks:
http://www.epa.gov/safewater/protect.html

EPA Source Water Assessment Program web site providesgeneral program information and links to state programs:
http://www.epa.gov/safewater/protect/swap.html

The EPA's Safe Drinking Water web site includes frequently asked questions (FAQs) and outlines the major elements of conducting a source water assessment:
http://www.epa.gov/safewater/protect/assessment.html

EPA's fact sheet titled 'Community Involvement in Drinking Water Source Assessments' explains the four steps of source water assessments; how communities can participate in the assessment process; and how communities can utilize assessment information for source water protection:
http://www.epa.gov/safewater/protect/factsh4.html

California Department of Health Services (DHS), Drinking Water Source Assessment and Protection (DWSAP) Program site provides an overview of the program, information on state assessments and local protection programs:
http://www.dhs.ca.gov/ps/ddwem/dwsap/DWSAPindex.htm

DHS' DWSAP Source Water Protection Programs site provides frequently asked questions, references, training materials, funding opportunities, case studies, and information on other resources:
http://www.dhs.ca.gov/ps/ddwem/dwsap/protection.htm

Additional Information

Copies of the complete assessments may be reviewed at the district's office located at 5750 Almaden Expressway in San Jose, CA. If you would like more information about the DWSAP, please contact Ms. Frances Brewster at (408) 265-2600.