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Daylighting Poinsett Creek
How to uncover - "daylight" - and restore a strip of long-culverted creek as part of a city-wide storm drain renovation program, while maintaining enough urban park environment to please neighbors, was a challenge recently faced by the East Bay's City of El Cerrito. When the city decided to overhaul its storm drain system, a creek restoration approach offered a perfect opportunity to improve water quality (by filtering urban runoff before it reaches the Bay) and to save the costs associated with maintaining culverts. And Poinsett Park - a city-owned patch of dry grass seemed the ideal site to try it.
"By introducing water and creek-related landscaping we hoped to demonstrate an attractive, interesting, cost-effective way to help us meet our clean water goals," says City Planner Ed Phillips.
Although most area residents supported the project at first, as work progressed, some became dissatisfied when the site didn't conform to the conceptual drawings. The original design had to be altered to deal with the physical constraints of the site - a small, triangular patch of land on a very steep hill, with only about 250 feet (in length) by 75 feet (at the widest width) in which to recreate a natural creek. In addition, the streets on the north and south sides of the creek differed in height, creating a cross-slope height differential of about 3-4 feet, according to project manager Vern Phillips. Plus, neighbors wanted to preserve several existing areas of lawn. In order to please neighbors and meet the city's goal of accommodating a 10-year flood, the creek's banks and retention basins had to be made steeper and deeper than originally planned - leaving residents worried about children falling into the ponds or on the banks.
But engineers say the ponds, which will be fenced off at the steepest points, are necessary to slow the stream. "The upper pond slows the water before it flows down the creekbed, preventing erosion and scour of the channel," explains Vern Phillips. "And without the pond at the bottom there would not be enough storage capacity for a 10-year flood. We need that storage because we are tying back into existing, undersized storm drains, and without it there would be too much pressure on the pipe when the creek re-enters it." The ponds also had to be made deep enough to match the position of the existing pipes at either end.
Neighbors eventually agreed to forego the lawn areas in order to allow portions of the banks to be more gently graded. But some residents remain unhappy. Resident Sylvia Falcon sees the creek as a loss of "open space" and the addition of "engineered space". At meetings to discuss their concerns, a few questioned the value of open creeks at any cost, calling the creek "an industrial drainage ditch." The site, which will be planted with native trees and wildflowers this fall, currently consists of dirt slopes and raw rocks.
The city has held numerous meetings with residents to reassure them that there have been no accidents with other restored creeks in the Bay Area, that studies show that property values actually increase with proximity to creeks, and that open streams have environmental value for all of us. "Natural and open streams provide habitat for plants and wildlife, which in turn becomes our best flood control, erosion control, and pollution control device," says the Urban Creeks Council's Carole Schemmerling.
Since so many of Poinsett's complications revolve around pipes, maybe one lesson learned is to avoid putting creeks in them in the first place. "Years ago, people decided to culvert the creek, put it in an underground pipe, and build houses on top of it," says Vern Phillips. "Now because the metal pipes are failing, the city has to replace them and in some cases redirect the pipes out from under homes." Says Schemmerling, "People need to realize that any pipes put in the ground now will soon begin to deteriorate, whereas this newly-opened creek will only improve with time."
Contact: Vern Phillips (510)827-4900
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