A new website to predict flooding from local creeks could be available to the public as soon as late January, Len Materman, executive director of the San Francisquito Creek Joint Powers Authority, said Friday morning.
The flood-monitoring website will feature a color-coded map to identify locations and neighborhoods most likely to be affected. The new system will follow National Weather Service models of flood watches and warnings, with colors ranging from green for the least likely to red for imminent flooding, Materman said. The website will not replace the City of Palo Alto creek monitoring website, he added.
Palo Alto and parts of East Palo Alto and Menlo Park have been particularly vulnerable to flooding along San Francisquito Creek. Neighborhoods near the creek were flooded in 1998, and to a lesser degree in 2012.
The creek overflowed in December 2012 in East Palo Alto and damaged levees near the Gardens neighborhood. East Palo Alto's then-mayor Ruben Abrica secured state emergency funding to repair the levee and damage along Woodland Avenue, where the water undercuts the creek bank.
The new system won't alleviate flooding problems (a proposed, long-term flood-mitigation project is supposed to resolve those issues), but it will provide a more accurate picture of where and when flooding is likely to occur.
"What we've been doing in 2014 is installing new rain gauges and tapping into the existing stream-flow gauges on the Stanford property," Materman said.
Previously, the upper San Francisquito watershed had a single U.S. Geological Survey gauge in Foothills Park. Now, six new gauges cover the stretch of the upper watershed, which will help develop a better picture of the amount of upstream water, Materman said.
The new gauges and website will provide an important warning system, so that residents and emergency-services personnel will have adequate time to prepare and develop an evacuation procedure.
The single Foothills Park gauge gave officials a mere 45-minute warning of when water would arrive at the Chaucer Street bridge in downtown Palo Alto. But the additional gauges will provide an advanced warning of an hour and 45 minutes to two hours.
"That's a lot of water," Materman said. "It's almost equal to the amount for the seven days in the week before."
At one point the area received 1.5 inches of rain in one hour on Dec. 11, he added. But at its highest level of flow, San Francisquito Creek was only at 40 percent of what officials saw in December 2012.
"We were fortunate that the beginning of the storm was intense," he said, rather than later in the evening when area creeks were already swollen.
But additional storms, if intense, could pose a problem, Materman said, adding that "the key to our system is the intensity in a short period of time. The ground is so saturated now."
The gauges and website cost an estimated $100,000 to $150,000 dollars, with funding from the California Department of Water Resources, the Joint Powers Authority and the City of Palo Alto.
The Santa Clara Valley Water District has provided gauges and Stanford University is contributing hardware they already have on site, Materman added.
Staff is currently calibrating the new tools, which were put in place in November. Materman said he isn't sure when the website will be up and running, but he is shooting for the end of January.