What is Stormwater?
Stormwater is rainwater and melted snow that runs off streets, lawns, and other sites. When stormwater is absorbed into the ground, it is filtered and ultimately replenishes aquifers or flows into streams and rivers. Stormwater becomes a problem when it picks up debris, chemicals, dirt and other pollutants as it flows or when it causes flooding and erosion of stream banks.
In developed areas, however, impervious surfaces such as pavement and roofs prevent precipitation from naturally soaking into the ground. Instead, the water runs rapidly into storm drains, sewer systems, and drainage ditches and can cause:
- Downstream flooding
- Stream bank erosion
- Reduced water quality
- Changes in the flow rate of a stream
- Infrastructure damage
- Contaminated streams and rivers
Stormwater travels through a system of pipes and roadside ditches that make up stormwater systems. It eventually flows directly to a lake, river, stream, wetland, or coastal water. All of the pollutants stormwater carries along the way empty into our waters, too, because stormwater does not get treated.