The Clean Water Act (CWA) regulates all of the "navigable" water bodies in the U.S. The precise definition of navigable waters is important for specifying what impacts may or may not be allowed to the Waters Of The United States (WOTUS). However, since the inception of the CWA, numerous Supreme Court cases have challenged the definition of WOTUS. On May 27, 2015, the U.S. Army Corps of Engineers (USACE) and Environmental Protection Agency (EPA) issuing a new definition of WOTUS. While the new definition is already the subject of numerous lawsuits, it is now the new basis of the CWA.
|Graphic from SWCA, The Wire.|
So what does the new definition say? Well, it is pretty straight-forward. There are just 8 possible cases:
1. traditional navigable waters
2. interstate waters
3. territorial seas
4. impoundments (of 1 - 3 above and 5 below)
6. adjacent waters
7. five special groups of similarly situated waters
8. case-specific significant nexus waters
For more information, see this excellent article in SWCA's The Wire.