Storm water runoff – the rain that falls on streets, driveways, rooftops and other developed land — is one of the most widespread challenges to water quality in Washington state. It carries oil, grease, fertilizers, soaps, and waste from pets and failing septic systems into streams and other bodies of water.
DNR has set a goal to clean up and restore Puget Sound, because even the clean water that originates in the upland forests we manage can become polluted as it flows through urban and suburban areas.
One of the best ways to mitigate the negative impacts of urban and suburban storm water runoff is to reduce how much of it ends up in natural waterways. Trees and shrubs are part of the solution because they help detain storm water on-site, in addition to slowing its flow and reducing erosion. October is an excellent time to recognize the many benefits that trees provide, including reduction and filtration of storm water runoff, because they:
- Reduce storm water runoff by intercepting rainfall in their canopies where it is later re-released into the atmosphere.
- Slow down runoff rates and reduce pollutants by absorbing storm water through their roots.
- Store pollutants and transform them into less harmful substances.
- Create healthy soil conditions that allow rainwater to filter into the soil so that less flows down streets, sidewalks, gutters, and storm sewers.