FAQs

Originally titled the Federal Water Pollution Control Act, this law was first enacted in 1948, completely rewritten in 1972, and additionally amended by the Clean Water Act of 1977 and the Water Quality Act of 1987. The CWA is the primary federal law governing water pollution with the objective of restoring and maintaining the chemical, physical, and biological integrity of U.S. waters. The law targets point source and non-point source pollution, manages wastewater treatment, and protects wetlands. More information is available on the EPA website.

2022 marked the 50th anniversary of the Clean Water Act. Click here to learn more about the history of the CWA and to see the pollution impairment levels of U.S. waters 50 years later.

The total maximum daily load is the maximum amount of pollution a body of water can receive while still meeting water quality standards. TMDL is determined by adding theWaste Load Allocation (the existing/future pollution level) to the Load Allocation (estimated background pollution) added to the Margin of Safety (calculated uncertainty in meeting water quality standards). Evaluation of body of water’s TMDL includes analyzing watershed characterization, impairment status, data gaps and monitoring report, source assessment, load allocation, set targets, and implementation plans. The evaluation of TMDLs allow states to identify impaired bodies of water.

NPS pollution generally results from land runoff, precipitation, atmospheric deposition, drainage, seepage or hydrologic modification. NPS pollution, unlike pollution from industrial and sewage treatment plants, comes from many diffuse sources. Examples include parking lots, lawns, and crop fields. NPS pollution is caused by rainfall or snowmelt moving over and through the ground. As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters, and ground waters. Read more here.

Nutrients, such as nitrogen and phosphorus, are essential for plant and animal growth and nourishment, but the overabundance of certain nutrients in water can cause several adverse health and ecological effects. Read more here.

Escherichia coli (abbreviated as E. coli) are bacteria found in the environment, foods, and intestines of people and animals. E. coli are a large and diverse group of bacteria. Although most strains of E. coli are harmless, others can make you sick. Some kinds of E. coli can cause diarrhea, while others cause urinary tract infections, respiratory illness and pneumonia, and other illnesses. Read more here.

Total suspended solids (TSS) are particles that are larger than 2 microns found in the water column. Anything smaller than 2 microns (average filter size) is considered a dissolved solid. Most suspended solids are made up of inorganic materials, though bacteria and algae can also contribute to the total solids concentration. Read more here.

The water cycle is a long journey! After a rain or snow event, the water in your yard has two options: 1) flow into a storm drain or 2) soak into the ground. With option one, water flows off hard surfaces, such as driveways and parking lots, and runs into storm drains. Any residue on these surfaces is carried into the drain and deposited unfiltered in the river. With option two, rainwater or snowmelt leaches through the soil and eventually reaches an aquifer, a layer of permeable rock that contains the groundwater. Flowing through capillaries, the groundwater eventually reaches a surface water source and is discharged. If you live in the Big Sioux River watershed, your groundwater discharges in the Big Sioux River or one of its tributaries.

Choosing the right plants can be difficult. Resources such as Midwest Ground Cover can help you choose.

There are many resources for people looking to establish native grasses. Check out the MNDNR guide to establishing prairie grasses or these tips for planting native grasses.