The amount of groundwater pumped far exceeds what is naturally replenished by rainfall

Valley Water percolation ponds put water back into the aquifer. Photo courtesy Valley Water

By John Varela

John Varela

Local groundwater basins can hold more water than all 10 of Valley Water’s reservoirs combined and serve as our primary reserve in times of drought. Groundwater provides about 40 percent of the water used in Santa Clara County, and nearly all the water used in South County.

Because the amount of groundwater pumped far exceeds what is naturally replenished by rainfall, Valley Water’s groundwater management activities are critical to maintaining healthy groundwater basins.

Valley Water was initially formed in 1929 to manage groundwater, and the Board of Directors takes seriously our responsibility to sustainably manage this precious resource.

One important method Valley Water uses to manage groundwater responsibly is to establish groundwater benefit zones. A groundwater benefit zone is a geographic area that benefits from Valley Water activities, such as replenishing groundwater with local and imported surface water.

Other activities include monitoring and protecting groundwater from pollutants, and constructing, operating, and maintaining facilities that help sustain groundwater supplies.

Groundwater pumping charges collected from well users in the groundwater benefit zones fund these activities. The charges are based on the amount of water pumped.

The board is moving forward with a process to ensure well users continue to be charged fairly for the benefits they receive. Currently there are two groundwater benefit zones, which have not been updated in some time. Valley Water recently conducted a scientific study to evaluate these zones. Our goal was to ensure the zones reflect as accurately as possible the areas benefitting from Valley Water activities.

The study was conducted by a consulting company specializing in developing, protecting, and managing groundwater and surface water resources. It looked at how water flows underground using data from the U.S. Geological Survey and other agencies. Local data was also used to understand the effect of Valley Water activities on groundwater levels. The study was reviewed by independent experts, who found the study approach and results to be thorough and equitable.

Because zone changes have the potential to impact many well users, Valley Water conducted extensive stakeholder engagement on the preliminary study recommendations. This included presentations to the board’s Agricultural Water Advisory Committee, letters to hundreds of well users in areas where proposed zone changes would add or remove wells from zones, three public open houses, and numerous phone calls, emails, and meetings with individual well users.

Based on the results of the study and input from stakeholders, Valley Water’s groundwater management team recommended making changes to the benefit zones. The Board of Directors agreed and directed our team to take the next steps and prepare the survey description to modify the two existing zones and to create two new zones in South County. These changes will be considered by the board in a public hearing in the first half of 2020.

If the recommended zone changes are adopted at the upcoming public hearing, about 800 wells in the county will be removed from the benefit zones, with about 500 of those wells located in South County. Those well users would no longer be subject to groundwater charges once the changes go into effect, likely in July 2020. About 10 South County wells would be added to a zone, and Valley Water has reached out to those individual well users.

The study did not evaluate the rates that are charged within the zones. The rates for the new and modified zones will be determined and set through Valley Water’s normal rate setting process. Groundwater rates for the new and modified zones are expected to take effect in July 2020.

It’s important to understand that your groundwater bill is based on how much groundwater you use, and the Valley Water activities that benefit your zone. We are committed to ensuring these zones continue to be fair.

Valley Water’s total revenue will not change as a result of the proposed zone changes. Our rates are based on our costs, and the re-structuring of the benefit zones divides those costs more equitably to well users benefiting from our activities. On average, Valley Water replenishes two-thirds of the groundwater pumped in South County. Without these services, our groundwater supply would not be sustainable.

As our county grows and the climate changes, know that Valley Water is working every day to ensure you have reliable and sustainable groundwater today, tomorrow and into the future.

To learn more about the groundwater benefit study zone or to sign up for related notifications, please visit: www.valleywater.org/gwbenefits or contact project manager George Cook at (408) 630-2964.

John Varela serves on the Valley Water Board of Directors representing South Valley. This column originally was posted Jan. 14 on www.valleywaternews.org.