What is Total Maximum Daily Load (TMDL)?
A TMDL or Total Maximum Daily Load is a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards. A TMDL is the sum of the allowable discharge of a single pollutant from ALL contributing point and nonpoint sources. The calculation must include a margin of safety to ensure that the waterbody can be used for the purposes the State has designated (ex. fishing, swimming, or drinking water), and must also account for seasonal variation in water quality.Water quality standards are to be set by individual States, Territories, and Tribes. These entities identify the uses for each waterbody and the scientific criteria to support that use. Purdue’s water quality research facilities are used to study how various management practices can affect discharge from agricultural operations. Further information about TMDL’s at the national level can be found at the U.S. EPA’s TMDL site. Information on what the State of Indiana’s work on TMDL’s ca
