Stormwater (runoff) is rainwater that does not soak into the ground. It flows over roofs, pavement, bare soil and lawns into storm drains. A stormwater system manages the flow of stormwater during storm events to help prevent flooding. Runoff can pick up pollutants, sediment, and debris that are harmful to plants, animals, and humans. These pollutants can affect the river, streams, and waterways of this region.