Oro Loma and Castro Valley Sanitary Districts Celebrate Completion of Horizontal Levee Construction with Public Event on November 14
SAN LEANDRO, Calif., Oct. 29, 2015—On Thursday, April 9, construction started on an innovative shoreline experiment that may help the Bay Area adapt to projected sea rise and extreme weather. Construction of the experimental levee is now complete, and Save the Bay will initiate planting efforts on November 1, 2015.
The public is invited to tour the horizontal levee project and learn from project experts on November 14, 2015 from 10:00 AM – 2 PM at Oro Loma Sanitary District, 2600 Grant Avenue, San Lorenzo, CA 94580. Tours of the wastewater treatment plant will be offered. Experts will speak about the project and how the concept could be expanded to protect large portions of the shoreline. Ice cream and espresso drinks will be served.
The Oro Loma horizontal levee project includes a wetland basin and a new type of levee known as a “horizontal levee.” This wide, gently sloping wedge of gravel, mud and grasses mimics a historic wetland ecosystem that existed before settlement in the Bay Area. Treated effluent from the Oro Loma facility will flow into the basin, be piped to the top of the horizontal levee, and flow through the soil to sustain native plants. This vegetation will provide wildlife habitat and remove nutrients that threaten water quality. Most significantly, engineers see the horizontal levee as a natural buffer that can absorb storm surges and provide natural protection from flooding at a fraction of the cost of traditional levees. If successful, the approach could reduce the cost of typical flood response by half.
“If you can create a really wide rough levee, [covered with plants], it will slow waves down, and maybe you can actually build a smaller levee. Also, what we’re building in these cases is not technically a levee, but a sloping terrace, or ramp, against a levee,” said Peter Baye, Coastal Ecologist.
“Our project resulted from a discussion between a wide range of environmental, engineering, residents and business interests along the Hayward Shoreline. It is an indication that many diverse opinions find merit in the concept. Oro Loma is proud to partner with Castro Valley Sanitary District and the community to provide a place to advance the science of sea rise response,” commented Tim Becker, Oro Loma Sanitary District Board President
Phase I of the project is now completed, and community volunteers mobilized by the regional environmental nonprofit group Save the Bay will plant more than 70,000 native plants in November/December 2015. Researchers at the University of California, Berkeley will lead the monitoring effort to quantify the effectiveness of the levee. The experiment will provide a much-needed field test of how treated wastewater and these new kinds of levees can help address critical flood protection, water quality and wildlife habitat issues.
Project partners include Oro Loma Sanitary District,Castro Valley Sanitary District, East Bay Dischargers Authority,California Department of Water Resources, the San Francisco Estuary Partnership, and Save the Bay.