Ok, I don't post a lot of environmental law cases, but this one obviously is pretty big.
The Miccosukee Indians challenged aspects of South Florida Water Management District's implementation of the Everglades cleanup on the basis that they hadn't properly permitted their activities regarding one of the big pumping stations (S9) under the Clean Water Act. Basically, the argument is that the pumping of water from east to west (against the basic flow) combined with the levee system, had the effect of discharging pollutants (picked up in runoff in the more urbanized areas to the east) into the Everglades. Basically, SFWMD pumps the dirty water west, where the levees slow or prevent it from moving back east and instead allow the waters to flow south into the Everglades.
The District Court and the 11th Circuit both held that because SFWMD pumped water from one water body into another, it needed a permit under the Clean Water Act.
SFWMD and the US argued that the act of pumping from one body of water (the canals, etc.) to another didn't constitute a discharge because the water bodies were the same (e.g. that the levees that separated them didn't create distinct bodies of water). They later argued (and this will be a big deal on remand) a "unitary" theory that ALL navigable waters (and therefore under US and CWA jurisdiction) are one body and that there is never a need for a discharge permit to move water from one to another.
The US SCt determined that summary judgment was improper (at this stage) and remanded for further determination of whether the two areas (separated by levees) in fact constitute separate water bodies and also for argument on the "unitary" theory.
Setback for the Tribe, but no slam dunk victory for any side.
Here are the syllabus, the opinion, and a concurrence/partial dissent by Justice Scalia.