There are two cases currently under deliberation by our Supreme Court.
They're smallish cases that could have a huge impact on our federal goverments ability to regulate water pollution. Currently nearly any wetland is considered a 'navigable waterway' by watershed delineation. This is under dispute.
The cases essentially question the Clean Water Act and it's limitations (or lack of) to wetlands. Results could have a huge impact on how wetlands are currently protected.
It will be interesting to see how Roberts and Alito come down on this.