Rainstorm Doubles, Triples Water At Santa Clara County Reservoirs

While water levels in some reservoirs in Santa Clara County had doubled and even tripled by Friday morning thanks to Thursday’s heavy rainstorm, the water supply remains below average for the year, a water agency official said.

The storm’s rain increased the water in the county’s 10 reservoirs by 5,000 acre feet to 55,000 acre feet, but that is only 70 percent of what the dams have in an average year, said Aaron Baker, raw water operations manager for the Santa Clara Valley Water District.

“It really isn’t that big of an uptick,” Baker said. “This one really didn’t produce that much.”

The water district had hoped for 10,000 to 12,000 more acre feet from the storm, but “the rainfall was not as high as some of the estimates,” Baker said.

One of the factors that reduced water runoffs into the reservoirs was that the dry watersheds in high elevations in the county soaked up a lot of the rainfall and kept the water from flowing into the valleys, Baker said.

With water levels at only 70 percent of the yearly average so far, “we’re not near normal,” Baker said. “It’s going to take quite a few more rainstorms.”

Meanwhile, district officials are hopeful that a storm forecast to move over the county from Sunday evening through Tuesday could drop water on the now-wet upper watersheds and send more flows into the reservoirs, he said.

[Related: Good News: Rain Is Much-Needed; Bad News: It’s Only ‘Short-Term’ Drought Relief.]

California is in the third year of a severe drought and so the county has had to tap into a lot of groundwater and continues to import an average of 55 percent of its water supply from state and federal sources, Baker said.

According to the water district’s website, all but one of the county’s reservoirs reported higher levels of acre feet as of this morning over Thursday.

The exception was Vasona reservoir in Los Gatos, which actually overfilled to 107 percent of its 495-foot capacity during the storm and fell back to 99 percent today, the water district reported.

The rainstorm, from noon Thursday to noon today, brought 2.37 inches of water recorded at Mineta San Jose International Airport and hit a high of 3.34 inches at the Uvas reservoir near Morgan Hill, according to the National Weather Service.

One of the biggest beneficiaries of the storm’s downpours was the Stevens Creek reservoir off Stevens Canyon Road near Cupertino, which went from 472 acre feet on Thursday to 1,215 acre feet this morning, about 39 percent of the water it can hold.

On Dec. 1, Stevens Creak was at its lowest level of the year, 158 feet, or just 5 percent of its capacity, according to the water district.

Two other dams cited by the district as among the shallowest in the county prior to the storm, Guadalupe, off of Hicks Road south of Los Gatos, and Uvas, in the foothills along Uvas Road south of Morgan Hill, both recorded large amounts of new water.

At Guadalupe, which at 120 feet stood at only 4 percent of its capacity on Dec. 1, the level doubled in one day from nearly 223 feet early Thursday to 491 feet, or 14 percent of its capacity, by today.

Water at Uvas, the reservoir that recorded the lowest capacity level in the county at only 2 percent as of Dec. 2, jumped by three times during the day, from 388 acre feet Thursday to 1,165 feet this morning, reaching nearly 12 percent of its capacity.

Another big gain came to Chesbro, by Oak Glen Avenue southwest of Morgan Hill, where the water level more than tripled in the single day, from 95 feet Thursday to 361 feet today, although that still is only 4.7 percent of its capacity.

The county’s larger reservoirs also posted significant rises, such as Calero, along McKean Road outside of south San Jose, which increased from 4,057 feet Thursday to 4,337 feet today, or more than 43 percent of its capacity.

Coyote reservoir, northeast of Gilroy, after falling to a 2014 low of 6,961 feet on Nov. 2, went from 6,996 feet Thursday to 8,217 feet today, about 35 percent of the water it can take in.

The Anderson reservoir, northeast of Morgan Hill, was at 33,602 feet Thursday and recorded 34,396 feet today, now at 38 percent of capacity.

Lexington, in the foothills along state Highway 17 near Los Gatos, which reached an all-year low of 2,380 feet on Nov. 30, rose from 3,400 feet Thursday to 4,905 feet today, or 28 percent of its capacity.

The Almaden facility, along Alamitos Road in south San Jose, reached its low level at 277 feet on Nov. 29 but went from 380 feet Thursday to 681 feet today, which is 44 percent of its capacity.

See also:

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• Good News: Rain Is Much-Needed; Bad News: It’s Only ‘Short-Term’ Drought Relief
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• For Locals In Need: Red Cross Running Storm Shelters In Santa Rosa and Lake County
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• Before Storm Hits, Check Your Homeowners, Renters Policies
• For Locals In Need: Red Cross Running Storm Shelters In Milpitas and San Mateo

--Bay City News

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