In the last four decades, the Santa Clara Valley Water District has invested more than a billion dollars in reducing flood risks, protecting more than 93,000 properties in previously flood-prone areas. As the flood protection agency for the county, the water district works to protect as many parcels as possible through strategically designed flood protection projects and annual stream maintenance which includes sediment removal, bank repair and vegetation management.
However, flood risks still exist in our county, with more than 66,000 parcels in flood-prone areas. The water district currently has 18 projects underway to minimize this risk. Flood protection projects are a large and multi-faceted undertaking that include planning, design and construction phase, and oftentimes a permitting phase after design. In the initial stages of each project, it is essential to gather support and evaluate existing risks, potential benefits, environmental impacts and costs. Support from the community and agencies at local, state and even federal levels is crucial for a successful project.
As seen with the improvements to the lower and downtown portions of the Guadalupe River, flood protection projects improve a creek’s capacity to withstand strong storm events and protect homes and businesses. Previously downtown San Jose and Alviso experienced historical flooding on multiple occasions in the 1980s and 90s. Both regions, addressed by flood protection projects completed by 2009, were in partnership with the U.S. Army Corps of Engineers. When the upper reaches of the Guadalupe River are completed, the entire project will protect more than 7,500 parcels from a 100-year flood event.
The devastating impacts of the recent flood event along Coyote Creek on President’s Day are a reminder that flood risks persist. During the wettest winter in over 20 years, our watersheds were saturated and increased run-off filled our reservoirs and raised creek levels. Anderson Reservoir, our county’s largest reservoir, has received a lot of attention and at times, has been attributed as the source of the flooding. However, there are a few key facts to clarify.
Anderson Reservoir was less than half full on Jan. 1, 2017. Prior to January, we were in a historic drought, and there was no way to predict if we were facing another year of drought. After the first series of storms in January, we began releasing water from the reservoir on Jan. 9, as it became likely that winter storms would fill the reservoir, exceeding seismic safety restrictions. Heavy rainfall from January and February storms caused more water to flow into the reservoir than we could physically release. The reservoir reached its capacity and began to spill on Feb. 18. The subsequent storms resulted in the largest flow of water ever recorded over Anderson’s spillway.
Our hearts go out to those impacted by the recent flooding event. The water district is committed to reducing flood risks in the affected areas of San Jose. Since the President’s Day storm event we have reached out to our federal and state legislators for support in seeking assistance and funding to prevent future flooding.
We are also working closely with the City of San Jose to update creek capacity thresholds and develop a joint Emergency Action Plan. At the request of Mayor Liccardo our board of directors approved repurposing up to $450,000 in an existing contract between the water district and the San Jose Conservation Corps to help the city in flood response efforts.
The water district will host a special board meeting on the President’s Day flooding event on March 29, 2017. We will also host a series of post-flood community meetings in early April to analyze the event and how we can reduce flood risks in the future. We will need continued community and agency support in reducing flood risks in our region.
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