Palo Alto Weekly

News - April 30, 2010

Fixes eyed for flood-prone bridges

Flood-control agency proposes bridge fixes, bottleneck removal for neighborhoods around the San Francisquito Creek

by Gennady Sheyner

Seeking to protect Palo Alto, East Palo Alto and Menlo Park from the volatile San Francisquito Creek, a regional flood-control agency has proposed a new plan to fix up bridges and remove bottlenecks at some of the flood-prone areas along the waterway.

The proposal, which will be presented to city councils and neighborhood groups in the next two months, calls for modifying at least two, and possibly four, bridges along the creek. This includes the Middlefield Bridge and low-lying and troublesome Pope-Chaucer Bridge, which was overwhelmed by water in the 1998 flood.

Len Materman, executive director of the San Francisquito Creek Joint Powers Authority, said modifying the bridges along the creek would be an important first step in protecting property owners between U.S. Highway 101 and Middlefield Road from major floods. He is also proposing to remove debris and other structures that decrease the amount of water the creek can hold.

"There are several locations between Highway 101 and Crescent Park where there are structures in the channel," Materman said. "In some cases these are rocks that were placed there a long time ago because people thought that would stabilize the creek."

Materman estimated that these measures alone would contain a "50 year flood" — a flood that is projected to happen once every 50 years.

Materman, whose agency includes officials from Palo Alto, East Palo Alto, Menlo Park, the Santa Clara Valley Water District and the San Mateo County Flood Control District, said it's not yet clear what types of modifications the bridges would require. Some might have to be completely rebuilt, while others may require less drastic fixes.

The ambitious new proposal is the latest attempt by the creek authority to protect the three cities from floods like the one in 1998, which damaged more than 1,700 properties and which is considered a 45-year flood. The effort received a major boost last July when the participating cities agreed to modify an old levee and widen a downstream channel in East Palo Alto, where the flood threat is most acute.

The state Department of Transportation is also working on its own major project — rebuilding the section of U.S. Highway 101 over the creek. The Caltrans project is expected to be completed in 2012 and improve water capacity between Palo Alto and East Palo Alto.

The creek authority's plan would supplement these projects. At last month's meeting of the group's board of directors, Materman presented four upstream alternatives.

The most rudimentary alternative involves modifying the Middlefield and Pope-Chaucer bridges along with the bridges at University Avenue and at Newell Road and removing bottlenecks. The other three alternatives add flood-control measures that would enable the creek to handle a 100-year flood.

These additional measures include building floodwalls along the creek, between U.S. Highway 101 and the Crescent Park neighborhood; constructing an underground bypass channel for water between 101 and the eastern portion of Palo Alto; and building an upstream detention basin, which would hold surges in water volume, such as during heavy rains. If all the participating cities agree to build a bypass channel, only the Pope-Chaucer and the Middlefield bridges would be modified.

Estimated costs for the projects range from about $34 million (fixing all four bridges and removing bottlenecks) to $82 million (two bridges, bottlenecks and a new underground bypass).

Materman called the "detention basin" solution one of the best options for preventing a flood, but the proposal has been a tough sell so far. The most feasible location for such a structure would be on property owned by Stanford University. So far, Stanford has been reluctant to let the creek authority use its land for flood control, though Palo Alto Mayor Pat Burt, who sits on the authority's board of directors, said the option is still "on the table."

The ultimate goal of all the pending projects is to protect the communities around the creek from a 100-year flood — a phenomenon that the U.S. Army Corps of Engineer estimated would cause 25 times as much damage as the 1998 flood. The Corps is in the midst of its own flood-protection study for the San Francisquito Creek — an endeavor that has lagged because of inadequate federal funding.

Art Kraemer, who lives in Crescent Park near the creek, said the neighborhood's board of directors discussed the creek authority's latest plans at a meeting last week and agreed to support the most basic alternative, which they hope can eventually be coupled with an upstream detention basin.

"This alternative will solve the problem of 1998, but it won't solve the problem of a 100-year flood," Kraemer said. "The only real solution is for Stanford to allow the construction of a catch basin."

Staff Writer Gennady Sheyner can be e-mailed at gsheyner@paweekly.com.

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