Stormwater Runoff
What is Stormwater Runoff?
After a rain event, water that falls on natural surfaces infiltrates the ground and eventually into the groundwater.
Water that falls on impervious surfaces, such as roads, rooftops, and other paved surfaces, cannot soak into the ground. Instead, it flows over surfaces, picking up pollutants, such as oils, salts, debris, sediments carrying phosphorus, and other chemicals and depositing them into the lake.
Stormwater runoff isn’t just a problem along roads and commercial areas. Residential properties generate runoff as well.
Stormwater runoff from developed areas poses a significant threat to the water quality of Twin Lakes.
Relationship between impervious cover and surface runoff. Impervious cover in a watershed results in increased surface runoff. As little as 10 percent impervious cover in a watershed can result in stream degradation.
In Stream Corridor Restoration: Principles, Processes, and Practices (10/98). By the Federal Interagency Restoration Working Group (FISRWG) (15 Federal agencies of the U.S.)
What Are the Effects of Stormwater Runoff?
A decline in water quality and clarity from pollutants and sediment.
Impeded navigation due to sediment.
Increased weed and algal growth due to excess nutrients.
Unsafe water for swimming due to bacteria and pathogens.
Harm to aquatic life from debris, as well as hazardous materials (pesticides, paints, motor oil, etc.).
Erosion of stream banks and loss of habitat.
All of the above lead to a loss in water quality, damaging the economy and impacting, property values, and quality of life.
EPA
Oil and grease
Concrete truck washout
Construction chemicals
Construction debris
Leaves and other organic matter