New System Gives Advance Warning of Floods

The National Weather Service has launched a flood forecast system along the Santa Clara River, designed to give farmers and residents six to 12 more hours to prepare for any flooding fueled by El Nino.

Two years in the making and based on a complex mathematical model of the 85-mile river, the forecast system will be triggered when water flows at Montalvo indicate the potential for damaging floods.

“We can’t do anything to prevent floods,” said Robert Hartman, hydrologist in charge of the California-Nevada River Forecast Center in Sacramento. “All we can do is give people a little bit of time to get out of harm’s way. . . . We want to protect lives and property, and that’s really what we’re trying to do.”

Historically, only warnings of imminent flash floods have been provided on most rivers in arid Southern California.

However, warnings for longer-term flooding lasting longer than six hours are appropriate on large rivers such as the Santa Clara, which drains an area the size of Delaware, Hartman said.

In years past, hundreds of acres of farmland along the river have been lost to extensive flooding. More than 500 acres of farmland were swept away in just one location along the river in the winter of 1995.

The new system will enable officials to estimate when and how high the river will crest, and how long flooding will last, said Brent Bower, the hydrologist at Oxnard’s National Weather Service office who would issue the forecast.

The same forecast system has been put into place for the San Diego River and Orange County’s Santa Ana River, Hartman said.

Such forecasts are expected to be infrequent. So far no storm system this winter, including Friday’s, has justified issuing a flood forecast, Bower said.