After major floods in the Napa River in 1986, 1995, 1997 and 2006, the city of St. Helena wanted a comprehensive flood protection project to provide 200-year flood protection. Our flood control specialists designed flood control and drainage facilities, and helped prepare the correct documentation for the city’s protection.
We designed flood control facilities and interior drainage improvements. Our engineers identified levee encroachments, and designed to reroute exterior drainage. We also prepared the FEMA Conditional Letter of Map Revision request that documents the floodplain changes from the levee improvements. Our team coordinated public involvement to assist with community outreach. We attended meetings organized by the funding agency, and our exhibits and documents aided public understanding and project awareness. In the end, improvements to the entire system saw that the properties of St. Helena residents remained out of the floodplain.