Background

On Oct. 22, 2014, the U.S. Environmental Protection Agency approved Missouri’s Water Quality Standards regulation incorporating the Missouri Use Designation Dataset (MUDD), which increased the total miles of streams with “fishable/swimmable” uses from 24,482 miles to 115,772 miles. The MUDD assigned these newly “classified” streams with the following presumed uses:

  • Aquatic habitat protection
  • Human health protection
  • Whole body contact recreation – Category B
  • Secondary contact recreation
  • Livestock and wildlife protection
  • Irrigation
However, presumed uses shall not apply to water bodies that meet one of the following criteria:
  • Waste treatment systems, or prior converted cropland
  • Man-made structures which were constructed solely to treat or convey wastewater
  • Man-made bodies of water or structures which lack perennial flow and were constructed to treat, convey, or temporarily hold or slow stormwater following precipitation events
  • Water bodies that lack jurisdiction under either the federal Clean Water Act or Missouri Clean Water Law

With reasonable evidence, the department will make a written determination regarding the applicability of a water body’s presumed uses. The written determination is subject to appeal pursuant to section 621.250, RSMo. If it is determined that the presumed uses should not apply to the water body in question, the department will update the MUDD through a Water Quality Standards rulemaking.

Presumed Use Reviews – In Process

The department has reviewed presumed use applicability on water bodies for the following permittees. The department will incorporate any use changes as a result of these reviews into the current Water Quality Standards rulemaking.