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Winter Storms Bring Short-Term Mess, Long-Term Benefits
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Winter Storms Bring Short-Term Mess, Long-Term Benefits
By Linda Fridy
Santa Cruz County residents who had hoped for a wet winter to ease water supply worries got a reminder about being careful what you wish for. A major series of storms hit the state mid-January and set the stage for more damp weather.
The welcome rainfall came with unwelcome power outages, road closures, flooding and damage from falling trees and branches. By Jan. 20, nearly two dozen Santa Cruz County roads were impassable and thousands of residents were without power.
The Felton Grove neighborhood by the San Lorenzo River faced mandatory evacuation Jan. 20 as the fast-rising river jumped its banks, briefly turning area streets into tributaries.
Fortunately, the waters receded just as quickly, and the residents, veterans of winter floods, returned to assess the damage. It appeared limited to garages and carports, since most homes have raised foundations.
Dry days over the weekend allowed PG&E to whittle the power outages to fewer than 10 by Jan. 25, and only one road remained closed.
What Does Rain Mean for Water Supply?
Local water officials said the recent storms are encouraging, but the county needs more of the same to make up for the effects of the last three dry years.
The rains have a more immediate impact on the water supply for the Santa Cruz Water Department, which draws from surface water sources. During storms, moving water turns muddy and turbid, said Director Bill Kocher, so his department has to switch from drawing off of the usual rivers and streams and pull from Loch Lomond.
Loch Lomond has filled and is spilling over. That's good news, but it doesn't mean the district has an ample supply of water for the year.
The lake supplies only about 20 percent of what's used by customers in the city of Santa Cruz south through Live Oak to parts of Capitola.
The majority of the department's water comes from rivers and streams, and they need an extended pattern of steady rain with breaks to allow the water to seep into the water table, Kocher explained. That will feed the creeks throughout the summer.
"If it stopped raining tomorrow, we haven't made up for three dry years," said Kocher. "I think of Loch Lomond as our savings account. Our checking account is the streams and rivers. In the summer we have to make up for excess water demand [with water from] from Loch Lomond, and we don't like to draw too much from savings."
Soquel Creek Water District Wants Even More Rain
The need for a slow-and-steady rain pattern is even more vital to the Soquel Creek Water District, said Director Laura Brown.
That district gets its water from wells that draw from underground aquifers (underground chambers that are naturally formed and hold water).
The science to measure how much water is in an aquifer is still evolving, but everyone agrees that the ground needs a good soaking before rainwater can begin to recharge the supply in the aquifer.
The district is also certain that it is overdrafting the aquifer by taking more water each year than nature replaces.
In wells along the coast, the worry is that the water level will drop to a point that seawater begins to seep into the supply, known as saltwater intrusion.
Rains do have an immediate benefit on demand, as they eliminate the need to irrigate landscaping and fields during the winter months, Brown said.
They can also cause problems.
While Soquel Creek does not have to worry about muddy waters, it does need to maintain power at its well pumps.
"If power goes down at a critical well, storm events can become a water emergency," she said.
Her staff has generators tested and ready when storms such as the recent wave come through.
Better Monitoring
Soquel Creek Water District is working with the county and the U.S. Geological Service to study better ways of measuring its aquifers.
For the moment, "managing a ground water aquifer is not an exact science," Brown admits.
However, monitoring of wells for her district and river flow for Santa Cruz has come a long way in recent decades.
Brown recalled working for Santa Cruz during the winter of 1982, a 100-year-flood winter that resulted in mudslides such as the one that took out homes on Love Creek.
Back then, she recalled, the only way they had of monitoring the San Lorenzo River was an employee who lived upstream along the bank. She would go home and phone in how close the water was coming to the branches of a tree that leaned over the river.
When it got close to the branches she could see from her home, the department would prepare for flood levels downriver, Brown recalled.
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