For water experts, the year begins in October — the water year, that is. That’s because a water year is a 12-month period during which hydrologists measure precipitation and stream flows. Generally precipitation starts in late fall.
For California and specifically, Santa Clara County, the water year is off to a good start. Our first set of showers came at the end of November. Late November and early December storms dumped a healthy amount of snow over the Sierra Nevada mountain range. On Dec. 17, the snowpack was measured at about 82 percent of average. For Californians, this snowpack is an essential lifeline. Snowmelt feeds streams and helps supply the state’s reservoirs. And locally, nearly half of our water is imported from this original source.
This is an encouraging start, but our storm season has just begun and there’s no crystal ball to reveal whether we’ll receive enough rainfall or snow for our water supply needs.
The Santa Clara Valley Water District works to ensure a reliable water supply for Silicon Valley for a healthy, life, environment and economy. The water district manages groundwater basins and operates 10 surface reservoirs, three drinking water treatment plants, and a water purification center to ensure safe, clean drinking water for Santa Clara County.
Since the recent historic drought, the water district’s diligent water management and the community’s outstanding conservation efforts have allowed our groundwater levels to return to pre-drought levels. Since 2015, Santa Clara County residents have continued to save water by over 20 percent compared to 2013 usage. In the last two years, the water district has been able to replenish our groundwater aquifers with imported water from the San Joaquin-Sacramento Delta and local rainfall captured and diverted to percolation ponds and streams throughout the county. In fact, the water district has been able to refrain from filling ponds now that groundwater basin levels have rebounded. Continuing these efficient management and conservation efforts allows us to be prepared for the next drought.
Heading into the winter season, our reservoirs are at 26 percent of capacity and at 60 percent of the historic average for this time of year. It’s not unusual to see the reservoirs low at the start of the rainy season following a dry summer period. The first few rainstorms of the season help saturate the ground, and as winter progresses our reservoirs should start capturing more rainfall runoff. Our precipitation gauges have measured a range of rainfall throughout our county from 2 inches to up to 10 inches in the hills, with a central San Jose gauge measuring just under 3 inches to date.
As a reminder, be sure to turn off your irrigation systems for the winter season. For more tips on how you can save water visit our conservation programs and rebate pages.
You can keep up-to-date with local reservoir levels and precipitation measurements on alert.valleywater.org