Recent historic rainfalls in South County soaked the ground, threatened flooding and raised reservoir levels, but authorities say the drought is far from over and key local water supplies remain even lower than they were a year ago.
“As of last Friday (Dec. 12), even though we got about five inches of rain (in some areas), the reality is that we need six or seven more storms like that to get us through the drought,” said Santa Clara Valley Water District Director Dennis Kennedy, who represents South County on the board.
Last week’s storm, which dumped heavy, persistent rain on the area for more than 24 hours straight, brought about four inches of precipitation to southwest Morgan Hill, where local weather enthusiast Chris Henry keeps daily measurements.
Since that rainfall, a series of smaller storms hitting the coast this week have dropped another 2.67 inches on Morgan Hill as of 8 a.m. Dec. 17, Henry said.
That brings the total rainfall for December to about 9.62 inches, and the year-to-date tally to about 12 inches, which is about half the region’s average annual rainfall, Henry said.
Another frontal band moving in off the Pacific Ocean was expected to bring even more showers to South County Thursday and Friday, before tapering off Saturday, Dec. 20, according to National Weather Service Forecaster Bob Benjamin. Starting Sunday, chances of rain will be “dwindling to zero” with the area likely to remain dry at least through Christmas Day.
While some South County reservoirs saw sudden and drastic jumps in water levels following last week’s storm, it is the groundwater basin that has suffered most among local water sources during the drought, according to SCVWD spokesman Marty Grimes.
“That’s going to be the biggest challenge to recover,” Grimes said. “All that water (from storms) doesn’t percolate into the groundwater. We’re expecting our groundwater will be about 100,000 acre-feet less than it was a year ago, and that’s going to take many months to recover—maybe years.”
2013 was the driest year on record in the state of California. The Santa Clara Valley groundwater basin won’t be at a “normal” level until it’s holding about 300,000 acre-feet, and authorities are projecting it to be storing about 200,000 acre-feet at the end of this winter, Grimes said.
An acre-foot of water is enough to supply a family of five for two years.
By contrast, the district’s 10 reservoirs, which store surface water, have a total capacity of about 169,000 acre-feet, but were only holding 64,000 acre-feet as of Wednesday morning. Storage is up considerably at some of those reservoirs, such as Chesbro in southwest Morgan Hill, which jumped from 1 percent of capacity to more than 10 percent in the last 10 days.
“Once it starts raining, it’s impressive how (Chesbro and Uvas reservoirs) can rebound, but that does not mean the groundwater basin has rebounded as quickly,” Grimes said.
Another key drought factor that won’t be determined for months is the snowpack in the Sierra Nevada mountains, Kennedy added. Runoff from that melting snowfall supplies key sources outside Santa Clara County from which SCVWD imports water for the county’s 1.8 million residents.
As a result of these supply uncertainties, the district is still asking water retailers to cut water use by 20 percent, at least until the middle of 2015, Grimes added. The district does not supply water to individual residents, but rather sells it wholesale to retailers such as the cities of Morgan Hill and Gilroy.
It is the retailers’ responsibility to urge individual residents to conserve water through local restrictions. Morgan Hill, for example, is the only city in SCVWD’s jurisdiction so far to restrict outdoor watering to one day per week during the winter, Grimes said.
The City of Morgan Hill, for the month of October, reported the highest monthly rate of conservation—24 percent—of any local retailer since the call for conservation was initiated early this year. However, retailers countywide have cumulatively reported only a 12 percent total rate of conservation since February.
Although last week’s storm brought flooding, power outages and damages to areas north of South County, Morgan Hill was relatively unscathed, according to city staff.
While downtown Morgan Hill and other areas along Little Llagas Creek, which flows along the west side of Monterey Road, are prone to flooding during heavy rains, no significant deluges were reported.
“We had some standing water in the gutters, but no true flooding,” Morgan Hill Communications Manager Maureen Tobin said Tuesday. “We were really fortunate this big storm and yesterday’s rain didn’t cause any issues.”
Local officials remain determined to continue lobbying for federal funding to complete the $137-million-plus Llagas Creek Flood Protection project, which has been in the pre-planning stages for more than 50 years.
Kennedy said recent efforts to lobby Congressman Sam Farr resulted in an additional $12 million in federal funding for the 2015 Watershed Rehabilitation Program for the Natural Resources Conservation Service. Those funds are a good start, but a lot more work remains before the project becomes a reality.
“We’re still working to make sure that portions of the funding get to the Upper Llagas project, and not just for the program as a whole,” Grimes added.
