As 2016 comes to a close, we are encouraged by the fact that local groundwater storage has recovered significantly, due to the continued efforts of the community to use water sparingly and our robust efforts to replenish groundwater supplies.
The Santa Clara Valley Water District, Santa Clara County’s primary water wholesaler, works every day to ensure there is enough clean, safe water to sustain our region’s economic vitality and quality of life. The water district is also the groundwater management agency for Santa Clara County, and works to protect and build up our groundwater supplies.
In Santa Clara County, nearly half of all water used comes from groundwater stored in natural aquifers, or underground water basins, right beneath our feet. Groundwater is an essential source of our local water supply. Maintaining and managing our groundwater supply is crucial because we could face serious consequences if well users pump too much water without it being replenished naturally by rainfall, water percolating through creek beds, and other sources. Overdrawing a groundwater basin for long periods of time can cause significant drops in water levels and storage, and can even cause the land surface to sink due to compacted clay layers underground.
During the past four years of severe drought, the water district has worked diligently to monitor and maintain our groundwater levels. As you can imagine, the drought has made this difficult. In 2015, we ended the year our groundwater storage levels at 232,000 acre feet of water, within Stage 3, the “severe” stage of the Water Shortage Contingency Plan. Without the community’s success in reducing water use by 27 percent in 2015, groundwater storage could have dropped much further.
Due to the rain we received last winter and this fall and continued water savings efforts, the water district expects to end 2016 with groundwater storage levels of about 300,000 acre-feet of water, the lower range of Stage 1, the “normal” stage of the Water Shortage Contingency Plan, which is great progress. The water district actively works to replenish groundwater storage with available surface water by managing a groundwater recharge program. The estimated recharge amount in 2016 is about 140,000 acre-feet. That’s more than five times what was recharged in 2014, which was approximately 26,000 acre-feet. Needless to say conditions have improved.
However, it is important to remember that the drought is likely to remain through the winter in many regions currently experiencing drought, and it is too early to know whether our groundwater storage levels will remain in the normal range. If the rest of the season is dry, our groundwater storage levels could fall back into the alert stage.
The water district board continues its call for 20 percent water use reductions. While our conditions have improved, one winter’s worth of rain won’t erase the past four years of drought. Continuing to save water now helps prepare us for the potential of more years of drought.
Good to see ground water levels are on the increase.
The hope is that at the end of the 2016 season, at “the lower range of Stage 1, the “normal” stage of the Water Shortage Contingency Plan”.
Given that there is still room to improve the local ground water levels, why have water recharge via the peculation ponds near Guadalupe Creek ceased?
The pumps have been off for more than a week, and some of the ponds are dry.
Thank you for the question, Stieg. We’re writing a fuller explanation which we’ll post on this blog, but here’s the short answer. During the stormy season, we can’t divert creek water into our ponds because a) the dams used to divert that water must be removed to avoid creating a flood risk and b) currently, the water is very turbid and full of silt. If we divert that into our ponds, the silt would build up in the ponds, making them less effective and we’d have to drain and clean them again. The good news is that we have all year to release water into all of our ponds, and we expect that 2017 will be a good year in terms of groundwater replenishment.