The interstate rivers that make up the Apalachicola-Chattahoochee-Flint River Basin flow from Georgia into Florida. Florida claimed that its upstream neighbor was consuming too much of the Basin waters, resulting in downstream harm to Florida’s oyster fisheries and wildlife. The Special Master appointed to the case originally recommended dismissal of Florida’s claim for lack of redressability, but the Court requested that the Special Master examine the case on the merits. The Special Master then issued a report concluding that Florida had failed to prove by clear and convincing evidence that Georgia’s alleged overconsumption caused serious harm to Florida’s fisheries or wildlife.
Florida filed exceptions to that report, and the Court, in a unanimous decision by Justice Barrett, overruled the exceptions and dismissed the case. The Court noted that it had not previously established the causation standard for equitable-apportionment cases like this one, but held that Florida’s evidence was so lacking that it did not establish the necessary causation under any standard. Specifically, the Court found that there were many factors that led to the collapse of Florida’s oyster fisheries, and there was not clear proof that Georgia’s alleged overconsumption of Basin waters was a substantial factor, much less the sole factor, and found little evidence of any actual harm to any Florida wildlife.
The opinion in Florida v. Georgia is here: https://www.supremecourt.gov/opinions/20pdf/22o142_m648.pdf