What is Stormwater?

Stormwater runoff occurs when precipitation flows over the ground. Impervious surfaces such as buildings, sidewalks, and streets prevent stormwater from naturally soaking into the ground. Most water entering storm drains flows untreated, picking up and carrying numerous pollutants to our waterways and eventually into Lake Superior.

Common Stormwater Pollutants
  • Sediment: Soil, clay, and sand washed from lawns, driveways, and construction sites reduce water clarity, smothers habitat, and carries attached pollutants to waterways.
  • Nutrients: Animal, yard and garden waste, soil, and fertilizer containing nitrogen and phosphorus, which contribute to algae growth and consumes oxygen, which can harm aquatic organisms.
  • Pathogens: Disease causing organisms found in human, pet, and other animal waste.
  • Chemicals: Herbicides, pesticides, fertilizers, detergents from washing cars, heavy metals, and petroleum by-products. These toxic substances are harmful to aquatic, terrestrial, and human life.
  • Litter: Trash and debris diminish the natural beauty of our waters, degrading habitat and harming fish and wildlife.
Why is Stormwater Important in Superior?
Stormwater is the largest contributor of water quality pollution to the urban waterways in the US. The problem increases when development occurs without addressing stormwater pollution. When land is converted from its natural state to one of parking lots, buildings, lawns, streets, and sidewalks, rainwater that once soaked into the ground now flows over the impervious surface and becomes urban stormwater runoff. The water picks up pollutants such as dirt, fertilizer, pesticides, oil, and bacteria on its way to the nearest storm drain or waterway. Unlike sewage, this water is not treated and flows to a waterbody.

It's a Community Effort - What You Can Do
We all need to do our part to keep the stormwater clean, because the stormwater that reaches our waterways or infiltrates through the ground may contain pollutants. The local rivers, streams, and bays are all important to the citizens of Superior, for the aesthetic, recreational, and financial value they bring to the area. Perhaps most important, Lake Superior is the source of our drinking water!

Reducing Runoff Helps Preserve the Environment
Check out this segment of the Liquid Assets Minnesota documentary. The Minnehaha Creek Watershed District, partners with Park Nicollet Methodist Hospital and the city of Hopkins to develop ways to enhance water quality and reduce pressure on stormwater infrastructure.

Watch this webinar about ways Superior is handling surface water
Click to view the "Reducing Runoff Helps Preserve the Environment" video.