On Tuesday, Aug. 22, the Santa Clara Valley Water District Board of Directors directed staff to move ahead with two short-term proposals to reduce flood risks along Coyote Creek in the Rock Springs neighborhood of San José, which experienced flooding last February. The two proposals include an earthen berm of up to 5-feet tall and a vinyl sheet pile wall of up to 3-feet, to prevent the intrusion of water, and will be completed by approximately end of December.
“We have been working diligently these past few months to get measures in place before the rainy season to help protect these communities,” said Board Chair John Varela. “We witnessed the adverse effects from an extraordinarily wet winter and we are committed to reducing flood risks to help protect homes and businesses.”
After an evaluation including a hydraulic analysis, staff carefully analyzed options for establishing barriers along vulnerable areas. This stretch of Coyote Creek is a natural channel and any physical alternations to the creek could potentially redirect flood threats downstream. To prevent creating risks in other areas, staff evaluated various options to reduce flood risks in different neighborhoods.
The water district is currently working with the City of San José on agreements to allow for the removal of non-native vegetation along Coyote Creek on city-owned property, including affected areas near Selma Olinder and Watson parks as well as the mobile home communities near Old Oakland Road. In partnership with the city, this work could include removal of 15 acres of invasive vegetation along the creek to benefit ecological habitat and improve the creek’s capacity for carrying stormwater. These efforts will include removing acres of thickets of Arundo donax, a thick, invasive reed, which can reduce a creek’s capacity significantly.
These elements will help prepare for the upcoming winter season and will be part of a larger effort for a flood protection project on Coyote Creek. On June 13, 2017, the board approved modifications to the Coyote Creek Flood Protection Project included in the voter-approved Safe, Clean Water and Natural Flood Protection Program. The project was extended by 2.9 miles upstream to Tully Road to include vulnerable areas that were impacted in the recent flood. The board also approved revising the target level of 100-year flood protection to protection from a storm equivalent to the Feb. 21 event, which was approximately a 20-25-year storm, meaning a storm that has a 1-in-4 to 1-in-5 chance of occurring any given year.
The modifications will allow the water district to use local funding to work actively on reducing flood risks for the county’s longest creek and main waterway in the region’s largest watershed. The board continues pursuing state and federal funding for a 100-year flood protection project to remove parcels from FEMA-designated flood zones.
The water district is partnering with the U.S. Army Corps of Engineers to develop a feasibility study for reducing flood risks from Montague Expressway to Tully Road. On Thursday morning, Aug. 24, water district board of directors hosted key leaders from the Corps on a tour of the Rock Springs Playground which was submerged in up to 2 feet of water during the February flood. The district and the Corps have been working on finalizing a Memorandum of Agreement for the study.