Warning that rainwater might not be contained if the predicted El Nino storms hit the Bay Area this winter, local officials said they are making a number of efforts to reduce hazards to homes and residents if the volatile San Franciscquito Creek surges out of its banks.
Standing on a dike where the creek jumped its banks and flooded an East Palo Alto neighborhood in December 2012, city and county officials discussed their efforts during a joint press conference on Oct. 14.
Those efforts include clearing the creek of debris and vegetation that impede water from flowing to San Francisco Bay, a new website that will give residents in flood-prone areas a two-hour warning, adding berms and retaining walls in troublesome areas, and coordinating disaster and emergency response.
This winter's rainfall could equal or exceed that of 1998, when 70 homes in East Palo Alto and Palo Alto flooded, Palo Alto Mayor Karen Holman said. About 200 people were evacuated, and 1,500 properties were affected.
"While we can't control how much rain falls, we are committed to proactively doing everything possible to reduce the risks of flooding, supporting our communities and working with our neighborhoods to be prepared," Holman said. "Our first priority remains the safety of our communities and the protection of homes."
The broad collaboration is thought to be the first of its kind for reducing flood risks, San Mateo County Supervisor Dave Pine said.
"Hopefully, these efforts will make us all better off and protect our residents," said East Palo Alto Mayor Lisa Gauthier, whose home is in the Gardens neighborhood, which flooded in 2012. Although her home was not damaged, those of her neighbors two blocks away were, she said.
Since then, a 1 1/2-foot-tall berm made of concrete and sandbags has been added along 400 feet of the creek bank at the spot of the 2012 overflow, and another 600 feet of berm closer to the bay will be completed by Nov. 1, East Palo Alto City Engineer Kamal Fallaha said.
Another 2-foot-tall retaining wall will be constructed in the coming weeks along a section of creek on Woodland Avenue near University Avenue in East Palo Alto that will match the height of an existing wall on the Palo Alto side.
Palo Alto and Menlo Park officials have also shored up the area near the Pope-Chaucer Bridge with berms. The bridge is a bottleneck for debris, and plans are in the works to modify and widen it as part of a broader flood-control project through the San Francisquito Creek Joint Powers Authority.
Caltrans has been working this summer on a new, wider bridge over the creek that goes under U.S. 101, which will improve creek flow. That work won't be completed by this winter, but a retaining wall that currently keeps water from entering the work site will be removed this month so water can flow unimpeded during the rainy season, officials said.
Joe Teresi, a Palo Alto senior engineer, said a pump station built in 2004 is in place to move water faster away from Palo Alto. But the pump's action could result in water flowing more quickly toward East Palo Alto, so the pumps will be turned off when the water reaches a critical level, he said.
Crews walked the creek in August to identify potential blockage areas and have taken out vegetation and debris.
"Our city crews removed 2,700 pounds of trash and 750 pound of recyclables from Menlo Park's 1.3 miles of creek," Menlo Park City Manager Alex McIntyre said.
Additional sandbag locations are also being set up, and Santa Clara Valley Water District officials are looking at funding crews to help seniors and other residents with filling and delivering sandbags to their homes, board Chairman Gary Kremen said.
East Palo Alto will host a sandbag-filling event on Oct. 24 at the Tara Road municipal yard from 9 a.m. to noon. The city has 133 volunteer emergency workers at the ready and has conducted drills to aid residents should flooding occur and in the event of evacuations, Gauthier said.
The JPA also debuted a new website at sfcjpa.org/floodwarning, which displays a color-coded map showing the likelihood of flooding at key points along the creek and in specific neighborhoods.
"The site provides a two-hour warning where we can now anticipate points where the creek levels will over-top. The site also makes rain and creek-flow data during major storms both useful and user friendly," Len Materman, the creek authority's executive director, said.