Community Vote on Flood Protection
Ross Valley Ballot Notice
Community Workshop 3--Presentation
Flood Zone 9 Public Meeting
Official Notice to Property Owners
Engineer's Report
On December 31, 2005, at 3am, a flow of about 763,000 gallons per minute broke creek banks and flooded our streets—during a 100-year storm. Engineers use that term to describe a storm that has a 1% chance of occurring in any given year, not a storm that occurs only once in 100 years. In fact, Ross Valley has experienced three 100-year storms in the past few decades (1982, 1986, and 2006). Much of the Ross Valley storm drainage system currently provides about 5-year protection, meaning that it can be overwhelmed by a storm that has a 20% chance of occurring in any given year.
Engineers have now identified first-phase flood protection solutions for the Ross Valley that could contain a flood of last year’s magnitude. Removing constrictions that block creeks could quadruple flood protection, and contain floods during 20-25 year storms (those with a 4-5% chance of occurring). Adding detention basins upstream, to hold water and release it slowly, could provide 100-year flood protection.
Projects can only be undertaken with sufficient funding, which will come from local, State and Federal sources. Property owners may soon be asked to vote on a storm drainage fee to help fund the Ross Valley Flood Protection and Watershed Program. The County has sent notices to all property owners to advise them of a Public Hearing on the vote, scheduled for May 1, 2007.
