Stormwater runoff is a leading source of water pollution. Stormwater is often piped directly to surface waters, like lakes, rivers, streams and wetlands, or sent to retention ponds. In contrast, wastewater (sewage) is treated at a wastewater treatment plant before it is released to surface water.
Common pollutants in runoff include sediment, pathogens, salt, fertilizers, metals, oils, pesticides and trash/litter. These pollutants degrade the water quality of surface waters. Changes in land cover such as impervious surface (rooftops, parking lots, driveways, and streets) can increase the amount of water flowing to surface waters. These changes may result in water level fluctuations, bank erosion and vegetation changes, and nuisance algae blooms. Dakota County strives to ensure stormwater is treated and controlled on construction and development projects and works with local partner agencies to implement projects that address water quality and quantity issues.
Polluted stormwater contributes to beach closings, fish-eating advisories, excess algae growth, and poor water clarity, especially in urban lakes. It also impacts the quantities and varieties of plant and animal species that thrive in our surface waters.
Reducing stormwater pollution helps maintain the beneficial uses of our surface waters, like fishing and swimming, for us and future generations.
County Stormwater Pollution Prevention Program
A municipal separate storm sewer system (MS4) is a system of conveyances (roads with drainage systems, municipal streets, curbs, gutters, ditches, man-made channels, storm drains) that is owned or operated by a public body, such as a county, city, township, or other organization or agency. Storm sewer systems are not connected to a wastewater treatment system and are regulated as dischargers of stormwater to surface waters.
Dakota County is authorized to discharge stormwater from the storm sewer system and is required to maintain and implement a Stormwater Pollution Prevention Program (SWPPP) for its MS4 area. Learn more about the prevention program.
Reduce stormwater runoff from your home or property
Private lands and spaces contribute to stormwater pollution and runoff too. You can have a drastic impact on the water quality of your favorite fishing spot or swimming beach by making small changes in daily activities, household habits and property management. Learn easy ways to reduce runoff.
Low impact development
Low impact development involves using design principles to minimize the change in hydrologic conditions on a developed site by mimicking natural conditions that use existing grade, soil types and vegetation to hold or infiltrate stormwater. Find out more about low impact development in Dakota County.
Raingardens can be designed to manage stormwater from a single gutter downspout to an entire parking lot. Cities and the Dakota County Soil and Water Conservation District provide informational programs and assistance with raingarden projects for homeowners. Learn more about raingardens and find assistance programs for your raingarden project.
Additional stormwater resources
Minnesota Water, Let’s Keep It Clean is a complete package on stormwater education that contains information and resources for the public, educators and students on stormwater and pollution prevention. It is maintained by Metro Watershed Partners, a group of water resource educators in the Twin Cities metro area.
Metro Area Children’s Water Festival is an annual event to educate fourth-grade students about water resources and to present ways they can ensure a future where both quantity and quality of water resources are protected and managed wisely. Schools must register to attend the festival.