Stormwater Runoff

By Jean Meiners

Technician, Root River SWCD

Stormwater has an enormous impact on water quality, whether it’s runoff from farm fields or from urban hardscapes. Rain and snow melt can carry many types of pollutants into storm drains and surface waters. The MPCA regulates stormwater from municipalities, construction sites, and businesses that store material outside, to limit stormwater runoff and reduce pollution from stormwater.

Rain and snow melt run over the many hard surfaces in urbanized areas — roads, sidewalks, driveways, parking lots, roof tops, etc. — and pick up pesticides, fertilizers, oils, metals, road salt, sediment, trash, and other pollutants and carry them into storm drains. Storm drains discharge directly into lakes, rivers, streams, and wetlands (the water is not treated first) so stormwater runoff is a leading source of water pollution. In addition, stormwater runoff from hard urban surfaces travels quickly and in large quantities, which results in damage to rivers, streams, and wetlands; destruction of aquatic habitats; and elevated pollutant levels reaching surface waters. Pavement and other hard surfaces also prevent stormwater from soaking into the ground and recharging groundwater. 

• Prevent runoff pollution by picking up trash or properly dispose of it. Trash clogs drains and pipes causing flooding. Take it upon yourself to help keep a storm drain clear of debris. Learn more at Adopt-a-Drain – Minnesota. 
• Leaves, grass, and dirt contain phosphorus, which feeds the algae that turn lakes green. Keep them off streets and sidewalks. 
• Dog poop carries harmful bacteria and phosphorus. Pick up after your pets!
• Salt is harmful to waterways and aquatic life. Just one teaspoon pollutes five gallons of water forever. Sweep up leftover salt and reuse it.
• Reduce your home and driveway salt use. It only takes a coffee mug of salt to effectively treat a 20-foot driveway or 10 sidewalk squares. Only apply it when it’s at least 15º F since most salt stops working below this temperature. Sweep up salt on dry surfaces to reuse. 
• Maintain trees and other natural vegetation. Roots help filter many pollutants so maintaining tree and grassy areas, especially on sloping landscapes, can help reduce the negative impacts of stormwater runoff.
• Think ahead when building. If you are planning a construction project, consider how you will contain soil and other pollutants before you start digging. You may also need a permit to ensure your site preserves and protects water quality.