Saving Homes from Swollen Creek

Saving Homes from Swollen Creek

Susan K. Moffat

Download: Estuary News, February 2013 PDF

On a day of super-high “king” tides last December, Len Materman walked along the levee on the south bank of San Francisquito Creek. The Palo Alto Golf Course stretched off to the right and San Francisco Bay lay a half mile ahead. Beyond the channel to the left, rooftops of one-story homes in East Palo Alto peeked over the top of the levee. With their backyards running right up to the north bank levee and their foundations below sea level, these homes are highly vulnerable to flooding. So are homes upstream in Palo Alto, where 1,700 homes flooded in 1998 when this slender creek could not carry rainwater out to the Bay fast enough to prevent it from overflowing its banks.

Photo: Len Materman points to the marsh that will receive flood water after the San Francisquito Creek levee is lowered, making homes near the marsh and creek safer as well as providing habitat benefits. Photo by Susan K. Moffat.
Photo: Len Materman points to the marsh that will receive flood water after the San Francisquito Creek levee is lowered, making homes near the marsh and creek safer as well as providing habitat benefits. Photo by Susan K. Moffat.

On his phone, Materman pulled up a recent photo of the spot where he was standing. It showed the water nearly at the top of the levees during a moderate storm — the sort that happens every five years or so. If all that rain had fallen on this day, when a king tide was pushing Bay waters more than two feet above a typical high tide, the homes could have flooded.

Materman is head of the San Francisquito Creek Joint Powers Authority, and it is his job to protect Palo Alto, East Palo Alto, and Menlo Park from the excesses of the creek and the Bay. He is leading a project to improve flood protection and also provide habitat benefits along the stream and at the wetlands near its mouth. The project will widen the creek channel by moving the southern levee over into the golf course to give flood waters another 7.5 acres to spread out. On the other side of the creek, downstream from the homes, the north levee will be lowered so that floodwater can flow more frequently into a wetland in the Don Edwards San Francisco Bay National Wildlife Refuge. The overall result should be not only safer homes, but a healthier marsh, nourished by mud and sand that will help it hold its own against sea level rise.

This approach is part of a regionwide project, dubbed Flood Control 2.0, that aims to manage sediment as an asset rather than a burden and to incorporate more natural methods of flood control. “We’re taking advantage of a time in history where the flood control infrastructure around the Bay needs maintenance,” says Caitlin Sweeney of the San Francisco Estuary Partnership, who is managing the $3.1 million project, which includes a $1.6 million U.S. EPA grant, as well as state and local funds. These dollars are not for capital costs, but will encourage innovation in planned projects through design workshops, data collection and analysis, monitoring, and information-sharing. “We want to seize the opportunity to think more broadly and redesign flood control facilities to increase the resiliency of watersheds in the face of sea level rise. And we want to incorporate habitat benefits too.”

San Francisquito Creek is just one of three Bay Area sites in the ambitious project, which also includes Novato Creek in Marin County and Walnut Creek in Contra Costa County. Four regional organizations are collaborating on the project, namely the Estuary Partnership, the SF Bay Conservation & Development Commission, the SF Estuary Institute, and SF Bay Joint Venture. And they in turn will be working with local agencies, flood control districts, and the public to monitor and share information on new approaches to creek and wetland management. The three pilot projects could become regional and national models for ways to combine restoration and flood control, and also help identify any regulatory changes needed to manage sediment to better benefit the environment.

Flood Control 2.0 will also help the SF Estuary Institute increase knowledge of the interface between creeks and the Bay, which is still relatively understudied. “These are nodes of ecological richness and complexity [as well as] high flood risk,” says ecologist Robin Grossinger of the project’s research team. The results of monitoring the effects of channel reconfiguration at San Francisquito Creek could help shape the design of the other two creeks in the program—and many others.  “It’s a fairly new thing, and a complicated subject scientifically, with a lot of technical, political and regulatory challenges. The reason we took this on is it’s not easy,” says Grossinger.

Check Out the Partnerships’s Flood Control 2.0 Projects

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