As rain falls to the ground it becomes known as storm water. Storm water that falls on pervious surfaces (grass, fields, natural areas, etc.) soaks into the ground without running off into streams and lakes. Storm water that falls on impervious surfaces (roofs, driveways, roads, sidewalks, etc.) is not allowed to soak into the ground and runs off into streams and lakes. As land is developed, trees are cleared and houses, buildings, and parking lots replace them. Runoff on hard surfaces occurs faster and in greater volumes. Increased runoff can create erosion problems, increase water pollution, and destroy stream habitat. Impervious surfaces also reduce groundwater recharge, which is a critical factor for cold-water streams such as the Kinnickinnic.
Check out our information sheet to find out about different types of storm water management features that the City utilizes to improve the effects of storm water.