As the rainy season approaches, multiple state, regional and local agencies are preparing for the potential impacts of the recent wildfires on urban and rural communities. There are 617 streams in the areas affected by fire in Sonoma County. Drinking water is safe and continually monitored, but because the county’s natural watersheds filter drinking water, it is critically important that ash, debris and other pollutants are prevented from entering stream systems to the maximum extent possible. In addition, creeks and streams within burned watersheds have elevated risk of flooding, debris flow and landslides due to increased rain runoff and potential for sediment and debris to fill and block channels and culverts.
Several local agencies are working collaboratively and independently, to assess and reduce the risk of flooding and to prevent fire-related debris, pollutants and sediment from burned areas from being carried into storm drains, creeks and rivers. Because of investment in data tools over the last several years, these agencies are rapidly performing hydrologic modeling to evaluate threats to the watersheds and to help establish priorities for recovery actions. Using data from NASA and other sources, agencies are able to track sources of pollution in the watershed that have the highest likelihood of moving into stream systems during this winter’s storms.
Partners include the North Coast Water Regional Water Quality Control Board (Regional Water Board), Sonoma County (County), the City of Santa Rosa (City), the Sonoma County Water Agency (Water Agency), the Sonoma County Agricultural Preservation and Open Space District (Open Space District), Sonoma County Regional Parks (Regional Parks), Sonoma County Department of Transportation and Public Works (Public Works), Sonoma and Gold Ridge Resource Conservation Districts, non-profit organizations and private partners.
The mutual goal is to protect human health, critical infrastructure (bridges, roads, culverts, flood protection facilities), wildlife, and the natural environment including streams and waterways. Efforts include:
- In urban areas, the City and the County in coordination with the Regional Water Board are cleaning and checking storm drains, and installing straw wattles and sandbags to prevent debris from entering storm drains. In addition, plans are being developed to capture, store, and treat storm water runoff from the most impacted urban areas. The Water Agency is evaluating impacts to flood management facilities and planning for additional maintenance and possible different operations to responds to increased debris, sediment and flow.
- In rural areas, the County is checking and installing debris-capture devices in culverts and ditches along rural roadways. The Open Space District is assessing district-owned properties within the burned areas for hazardous conditions including downed and damaged trees and areas where erosion may affect streams and watersheds.
- The Water Agency, Regional Water Board, Lawrence Berkeley National Laboratories and US Geological Survey are developing a water quality monitoring strategy to assess water quality conditions in local waterways.
- The Regional Water Board is also working with local erosion control and sediment control companies to determine supplies they have on hand, and how they can assist local agencies in quickly mobilizing. Several companies (The Wattle Guys and Stevenson Supply) have donated supplies and equipment to agencies in this effort to keep potentially toxic ash from entering creeks and streams.
Information on what property owners can do to reduce erosion and help prevent flooding will be shared at https://www.sonomacountyrecovers.org/ shortly.