The importance of imported water

How imported water keeps our local water supply healthy

When the Sierra Nevada snowpack begins to melt in the spring, it flows into reservoirs, creeks and rivers, and eventually the Delta, where the Sacramento and San Joaquin rivers meet. The Delta provides approximately one-third of California’s water, serving over 25 million residents and wildlife, and is transported through the Delta throughout the state by the federally managed Central Valley Project (CVP) and the State Water Project.

San Benito County receives its share of imported water through the Central Valley Project. This water is stored at San Luis Reservoir. From there it is pumped through the Pacheco Pass and into our county through a section of pipe called the San Felipe Project. Locally, this water is referred to as “federal” water or “blue valve water” since the pipes at the turnouts where farmers can access this water are painted blue.

For California’s water supply, April 1 is an important date. By then, water managers know how much water is available in the snowpack for the rest of the year. Accumulated levels of snow serve as a guide for federal and state water officials to manage the water needs of California’s populous and agriculture-rich state in the months ahead, while keeping enough water in the rivers and reservoirs for fish and wildlife. The amount of water provided by snow melt is dispersed throughout the state in allocations, which impacts various agencies’ operations.

Flood control operators depend on the information to determine how much water can safely be stored in a reservoir during rainstorms without potential flood risks to surrounding areas. Public utilities use the information to determine what percent of electric energy generation will be hydro power.  Agriculture interests use the information to determine crop planting, water pumping needs and irrigation schedules. Water agencies, like the San Benito County Water District (SBCWD), rely on this information to evaluate its water supplies and determine how to meet the community’s needs with both imported and local water resources.

The SBCWD has a contract for 43,800 acre-feet per year of CVP water. However, annual hydrology and environmental conditions in the Delta can profoundly impact the actual amount of water delivered. As a result, over the last decade, on average, the SBCWD has received a combined allocation of about 14,000 acre-feet/year.

Since 2013, the SBCWD has also participated in a water banking and exchange program with the Semitropic Water Storage District located in Kern County to help manage variability in imported water supplies.

The SBCWD can also store imported water supplies for shorter periods of time in San Luis Reservoir in Merced County, and locally in San Justo Reservoir.

To help manage the variability between wet years and dry years in California, the SBCWD also participates in both one-year, or “spot market,” transfers and exchanges as well as multi-year transfers and exchanges with other water agencies throughout the state.

When there is insufficient water to meet the county’s water demands through the SBCWD’s regular local and imported supplies, the district obtains water from other places in the state where there are excess supplies and purchases the water. Sometimes, like during the drought, this water had a hefty price tag.

Imported water supplies are critical to prevent the return of historic groundwater overdrafts in the Hollister Urban Area and surrounding groundwater basin.

Monitoring of our local groundwater basin began in the 1920s. As the population grew larger and agricultural activities increased the groundwater basin was being over taxed. In 1957, the financing for building and operating Hernandez Dam, and the reconstruction of the Paicines Canal and Diversion works were approved. Hernandez Dam was needed to protect our local groundwater basin from being in overdraft.

The county continued to grow and agricultural activity continued to increase. This put more strain on our groundwater basin and overdraft was once again a concern. This trend was only stopped after the SBCWD began importing water from the CVP in the 1980s.

The Hollister-San Juan groundwater basin benefit from the imported water because the purchased water helps balance the basin, is superior in quality to groundwater pumped from local aquifers and is more conducive to crop growth.

The two water treatment plants in the Hollister Urban Area, the Lessalt and the West Hills Water Treatment Plant (to be completed later this summer) process this water for home use. Taken together, the Lessalt and West Hills plants will increase the quality of drinking water throughout the Hollister area. It will allow the City of Hollister and Sunnyslope to decrease its pumping of lower quality groundwater, allow water recycling for local crops and assists the City of Hollister and the Sunnyslope County Water District in meeting State Water Quality Board wastewater discharge requirements.

Improved water treatment will also reduce the mineral content in local drinking water, reducing the need for water softeners in most areas and contributing to longer life for many household appliances.

While the landscape is looking greener, reservoirs are fuller and the Sierra snowpack is deep, it’s important to remember that drought could return next year. It’s important to continue the practice of valuing our water by making water conservation a way of life.

Shawn Novack

Shawn Novack is the Director of the Water Resources Association of San Benito County. The Association represents the City of Hollister, the City of San Juan Bautista, the Sunnyslope County Water District and the San Benito County Water District for all their water conservation and water resource protection programs. Shawn has been in the field of water conservation for 18 years. He has a certification as a Water Conservation Practioner from the American Water Works Association California/Nevada Chapter. He also is a Certified Landscape Irrigation Auditor through the Irrigation Association in Virginia. Before getting into the water industry, Shawn worked as a technical writer for the Naval Research Center in Monterey.