Top 10 Ways to protect groundwater Check out this fun "Groundwater Story" video Importance of groundwater
Groundwater is water that flows beneath the surface through small pores and cracks in the rock and soil. Throughout the world, the majority of available fresh water is in the form of groundwater. In Santa Clara County, nearly half of all water used comes from groundwater. The county's groundwater basins have vast storage capacity, estimated to be two times the capacity of all the district's 10 surface reservoirs combined.
Ensuring a reliable supply
Groundwater basins are naturally replenished by rainfall, water percolating through stream beds, and other sources. As natural recharge is not sufficient to replenish the amount of groundwater pumped, the district releases local and imported surface water through recharge facilities, which include streams and recharge ponds. This coordinated use of groundwater and surface water is critical for ensuring a reliable water supply, storing water for use during droughts and shortages, and preventing land subsidence, which is very costly to the community.
Ensuring a safe supply
Numerous sources can pollute groundwater, making it costly to treat or even unusable. Since the restoration of contaminated groundwater can take years, decades, or longer, the district works to protect the groundwater basins from contamination and the threat of contamination. The district's groundwater protection programs allow us to assess regional groundwater quality, identify and evaluate threats, and help prevent or mitigate contamination.
Groundwater Subbasins
Within Santa Clara County, the district manages two groundwater subbasins that transmit, filter, and store water: the Santa Clara and the Llagas Subbasins. These subbasins cover approximately 325 square miles and are bordered by the Santa Cruz Mountains to the west and the Diablo Range to the east. The aquifers that comprise the subbasins are made up gravel, sand, and silty sand deposits. In the Santa Clara and Llagas Subbasins, aquifers extend to depths of over 1000 feet in places. The Coyote Valley region of the Santa Clara Subbasin is fairly shallow, extending to a maximum depth of approximately 500 feet.
Both the Santa Clara and Llagas Subbasins contain confined zones and recharge areas. In the confined zones, lower permeability clay and silt deposits restrict the downward flow of groundwater and separate shallow and deep aquifer zones. These low permeability deposits also provide some natural protection to deeper aquifers as they restrict the movement of contaminants. Groundwater in the Santa Clara Subbasin generally flows to the northwest toward San Francsico Bay while groundwater in the Llagas Subbasin generally flows to the southeast toward San Benito County. A map of the subbasins can be found on the right side of this page.
Top 10 Ways to Protect and Conserve Groundwater!
- Keep in mind that we live on top of our drinking water and activities on the land surface can affect the quality of our groundwater.
- Get involved in water education and teach your family friends and neighbors: if you don’t want to drink it, don’t put it on or in the ground!
- Reduce household chemical use and properly dispose of motor oil and unwanted or unused chemicals and medications. Visit www.hhw.org or call (408) 299-7300 for more information.
- Select low water-use plants and limit the amount of pesticides and fertilizers used in your yard. Minimize runoff, which can carry chemicals into surface water and groundwater.
- If pesticides, oil, gasoline, or other hazardous products leak or spill onto your driveway or other hard surface, use kitty litter or other absorbent material on the spill. Do not wash down the area.
- Use water wisely. Take short showers, run only full loads of dishes and laundry, and repair leaks promptly.
- If you own a well, create a zone of protection around your well and inspect your well on a regular basis.
- Read the annual Consumer Confidence Report or Water Quality Report provided by your public water system.
- Be proactive about testing your well water quality.
- Have your septic tank inspected and pumped on a regular basis.
Check this out!
The Groundwater Story (Courtesy of the King County Groundwater Protection Program)
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