Preventing ash and debris from entering waterways is critical as we enter the rainy season. Tools such as wattles, screens and sandbags are commonly used to:
- Slow the flow and turbidity of runoff
- Filter runoff
People who live in burned areas, or downhill of burned areas, should be aware of increased risks for:
- Flash Flooding: Normally, rainfall is absorbed by vegetation and soils, reducing runoff. However, wildfires remove vegetation and may leave soil unable to absorb water, creating flash flood conditions. Flood risk remains significantly higher until vegetation is restored—up to 5 years after a wildfire.
- Mud and Debris Flows: Debris and ash, along with other sediments, can be picked up in flood waters and form mud and debris flows.
Multiple, federal, state, regional and local agencies are preparing for the potential impacts of the recent wildfires on urban and rural communities. These agencies are taking action to protect private property and critical infrastructure with the following actions:
- In urban areas, the City of Santa Rosa and the County of Sonoma are cleaning and checking storm drains, and installing straw wattles and sandbags to prevent debris from entering storm drains.
- In rural areas, the County is checking and installing debris-capture devices in culverts and ditches along rural roadways.
- CAL FIRE crews, the City, and the County are clearing fire debris from streams and storm water channels to reduce flood risks.
- The Sonoma County Agricultural & Open Space District, Sonoma County Regional Parks, and City of Santa Rosa Recreation & Parks are assessing their properties within the burned areas for hazardous conditions including downed and damaged trees and areas where erosion may affect streams and watersheds.
- The Sonoma County Water Agency will be installing rainfall and stream gauges in watersheds in burned areas and working to install radar equipment to improve early warning forecasts for residents in high-risk areas.