Why are the ponds going dry?

If you’ve walked past any of the Santa Clara Valley Water District’s recharge ponds lately, you may have noticed the water levels getting lower. Don’t worry; it’s all part of the plan.

“Recharge” ponds are used to recharge — or refill — our groundwater aquifers. These aquifers are an important piece of the water supply puzzle, storing more water than we can store in all 10 of our surface water reservoirs combined. Nearly half the water we use in Santa Clara County is pumped from these aquifers. Recharging our groundwater supports this use, and helps avoid problems like subsidence, where the ground can sink due to over-pumping.

Throughout the year, we fill our recharge ponds with rainwater that has been captured in our reservoirs, or with water that we have imported through the Sacramento-San Joaquin Delta.

We constructed these ponds strategically throughout the county in areas where water percolates easily into our aquifers. Like our reservoirs, they were intended to be filled and drained based on water supply or maintenance needs.

These ponds are water supply facilities, not intended as habitat for fish or wildlife. We found during the drought that most animals that were in the ponds tended to make their way back to the streams when the ponds went dry. But to avoid any unnecessary distress to native animals and to the habitat that may have sprung up around the ponds, we remind the community not to deposit their unwanted pet fish, turtles or other animals in the ponds. These ponds are intended to fill and go dry, not to support nonnative species.

The good news is through the efforts of the community to save water, beginning during the drought and continuing today, and through the carefully managed recharge of our aquifers, our groundwater levels have recovered from the drought and are in very good condition. That has allowed us to send more water to a groundwater storage bank near Bakersfield, where we store water for use during droughts, and from which we made withdrawals during our latest drought. Essentially, our aquifers are full, so to store the most water possible, we are able to send water to other underground storage areas. 

Depending on how wet this winter is, it could be several months or more before we fill the ponds again. However, a few ponds are expected to retain some water. These include two of the Penitencia-area ponds in East San Jose, the Camden ponds off Los Gatos Creek in Campbell, and some of the Los Capitancillos ponds in Almaden Valley. Also, we will continue to fill many of our ponds in the South County area where the aquifers are not quite as full. 

Our healthy groundwater levels are important to help us prepare for future droughts, which we know will come at some point. Because we don’t know when that will be, we encourage the community to continue to make water conservation a way of life. We will do our part to save water and to continue managing our aquifers to ensure they can help us weather dry times.