The maximum amount of a pollutant a body of water can assimilate without violating water quality standards.

A "maximum load," which is a mass/time unit which is usually derived from a        concentration target.  There is an example of this process in the Knife River TMDL section.

How do we chose which stream or lake gets a TMDL?

The State of Minnesota, through the Clean Water Act, is required to update a list of impaired waters every even year.  Impaired waters are those that are not meeting their designated uses due to not meeting the water quality standard for those designated uses.

Impaired Water:

Streams are organized by Use Classes, such as swimming, navigation or habitat. Each class may have different standards for many different types of pollutants. For example, a waterway that has swimming as a designated use has very strict fecal coliform limits so that swimmers do not get sick.  When a waterway is designated as"impaired," it does not fit the standards designated for its use class.  Minnesot'a impaired water list is called the 303(d) list.

Then what?

Once a water is listed, the state must develop a TMDL (within 15 years of being listed).

Who?

The Minnesota Pollution Control Agency (MPCA) administers the program at the state level, while the Environmental Protection Agency "approves" all TMDLs.  The MPCA can contract out the work involved in creating a TMDL.

The South St. Louis SWCD has been working on the Knife River TMDL (Turbidity) and has begun the first stages of a TMDL for Miller Creek (Temperature Impairment).