Treating and Delivering Groundwater
The Goleta Groundwater Basin provides a critical resource for the Goleta Valley--especially during periods of drought. Over the years the District has invested millions of dollars to protect and sustain the basin.
What is groundwater and how does it get from the basin to your tap?
Groundwater is water that collects naturally underground in the cracks and spaces in soil, sand and rock. Over time rain and runoff from rivers, creeks, and streams percolate into the soil, recharging the aquifer.
The Goleta Valley has long relied on groundwater, with private wells serving the community for generations before Lake Cachuma was built and the District was formed. In fact, even the District’s wells are now 30 to 45 years old.
Using its nine wells, the District accesses the water stored in the aquifer, which it then treats and serves to the community. Together, these wells are capable of producing up to 6,000 acre feet a year. That’s enough to meet the minimum public health and safety needs of the community.
After relying on water stored in the Basin to survive the drought in the 1990’s, all of the District’s wells were taken offline. Bringing them back into service during the most recent drought required significant investment.
How do the wells work? First, a series of pumps and motors extract water from the ground. The groundwater is then chlorinated. This process disinfects the water and also oxidizes naturally occurring minerals, like iron and manganese, which allows them to be readily removed through filtration. Treated groundwater is then fed into the distribution system for delivery and consumption by customers throughout the Goleta Valley. While this process seems simple, each well involves a complex set of mechanical equipment, and as the wells age they require significant ongoing maintenance, investment, and cleaning.
The District typically takes each well offline for several days a month to perform maintenance activities. When pumps or motors fail, or investment is needed to extend service life, the wells may be taken offline for several months or longer. These repairs are costly, but maintaining access to production during severe drought periods is critical. Eventually, in order to ensure the long term sustainability of the Basin, the District’s aging wells will need to be replaced.
While pumping groundwater is energy intensive, so is delivering water throughout the system.
Groundwater must be pumped up from the ground, and then across areas of different pressures zones and elevations, often uphill several hundred feet to reach customer homes. This has required significant modification of the District’s distribution system, which was originally designed to use a gravity fed system to deliver water from Lake Cachuma.
Instead, a series of pumps and motors operate in sequence to move water throughout the system.
As the District looks to the future, groundwater will continue to play an important role to help sustain the Goleta Valley. And continued maintenance and enhancements to the District’s wells and distribution system will ensure the long term health and viability of the Basin.
(Published October 1, 2019)