Groundwater

The 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 three groundwater subbasins have vast storage capacity, estimated to be three times the capacity of all the District's 10 surface reservoirs combined. This allows the District to store excess water in local subbasins so that groundwater can be withdrawn when additional supplies are needed.

Protecting our existing water supplies, infrastructure and programs is the top priority for meeting water supply needs far into the future. Locally managed supplies, such as groundwater, reduce our dependence on imported water and are less vulnerable to risk. The District proactively manages local groundwater resources to ensure a reliable and safe supply of groundwater is available both now and in the future.

The Groundwater Story
Watch this musical animation while learning about the importance of groundwater and how to help protect this hidden resource. The Groundwater Story is used with the permission of the King County Groundwater Protection Program. This Flash animation requires Macromedia Flash 5 or newer to view. The Groundwater Story

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 As natural recharge is not sufficient to replenish the amount of groundwater withdrawn annually, the District manages and operates an active artificial recharge program. Groundwater recharge 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
The District works relentlessly to protect the quality of local groundwater from contamination and the threat of contamination. Working together with local, state and federal regulatory agencies, and aggressively responding to pollutants such as nitrate, MTBE, and perchlorate, the District's groundwater quality monitoring programs identify and evaluate threats to groundwater quality and prevent or mitigate contamination. Through publications such as the Guide for the Private Well Owner and services such as free irrigation and fertilizer management assistance for farmers, the District's outreach efforts increase public awareness of the importance of protecting local groundwater resources.