Wildfires dramatically alter the natural landscape by removing vegetation and exposing soil to wind and rain. These changes substantially increase the risk of flash floods and debris flows, even in areas not usually prone to these hazards.
Normally, grasses, shrubs and trees slow rainfall and improve soil absorption. Leaf litter further protects the soil from erosive rainfall. Wildfires burn vegetation and leaf litter to ash, leaving the soil exposed and less able to absorb rain. The result is increased runoff which can produce flash floods and debris or mudflows. Creeks and streams can be easily overwhelmed by these flows, as can streets and homes located below hillsides. The increased flood risk may last five years or more until the vegetation is restored
City Public Works is preparing for potential post-fire storms by cleaning debris basins and channels, with particular focus on the urban interface, that is where wildland hillside and other undeveloped properties drain into City storm drain facilities (culverts and channels, etc.). The City has installed debris bollards and trash grates upstream of problem areas to help break up debris flows and assure drains flow freely, and City crews will monitor and clear drains throughout storms. Please help the City keep culverts and channels clear by removing brush and debris that may get into and clog City drains – this is a primary cause of clogged drains and local flooding during storms.
The City is coordinating with other agencies (County Watershed Protection District, Ventura County Public Works, US Forest, CalFire, etc.) to coordinate potential support needed during floods, as well as preparing for potential debris flows resulting from flooding of burned areas.
Please see the Ventura County Recovers for more information at: http://venturacountyrecovers.org/category/rain-ready/1