Supreme Court of the United States: While addressing inter-state water dispute between Mississippi and Tennessee, the Full Bench held that Mississippi’s ownership approach on its underground water would allow an upstream State to completely cut off flow to a downstream one, which is contrary to equitable apportionment jurisprudence. The Bench expressed,
Although the transboundary flow might be a mere “one or two inches per day,” that amounts to over 35 million gallons of water per day, and over ten billion gallons per year. So the speed of the flow, at least in the context of this case, does not place the aquifer beyond equitable apportionment.
The City of Memphis sits on the banks of the Mississippi River in the southwest corner of. Mississippi marks the City’s southern border of the Tennessee and hundreds of feet beneath Memphis lies one of the City’s most valuable resources: the Middle Claiborne Aquifer.
The Beginning of Dispute
Mississippi invoked original jurisdiction of the Court alleging that Tennessee’s pumping had taken hundreds of billions of gallons of water that were once located beneath Mississippi with regard to which it sought at least $615 million in damages, as well as declaratory and injunctive relief. Additionally, Mississippi claimed an absolute “ownership” right to all groundwater beneath its surface—even after that water has crossed its borders.
Mississippi argued that the Memphis Light, Gas and Water Division’s (MLGW ) pumping had altered the historic flow of groundwater within the Aquifer. Further, Mississippi conceded that though some water naturally flows from the part of the aquifer beneath Mississippi to the part beneath Tennessee but MLGW’s pumping had substantially hastened this existing flow, allowing Memphis to take billions of gallons of groundwater that otherwise would have remained under Mississippi for thousands of years. Consequently, it had to drill its own wells deeper to access the aquifer, and use more electricity to pump water to the surface.
Doctrine of Equitable Apportionment
The doctrine of equitable apportionment is invoked for allocation of a shared water resource between two or more States. (Colorado v. New Mexico, 1982 SCC OnLine US SC 219) It stands alone as the federal common-law principle for disputes over interstate water. The doctrine’s “guiding principle” is that States “have an equal right to make a reasonable use” of a shared water resource. Florida v. Georgia, 2021 SCC OnLine US SC 18
Application of the Doctrine
This Court has never before held that an interstate aquifer is subject to equitable apportionment, so Mississippi’s suit implicated a question of first impression. It was also pertinent that the Middle Claiborne Aquifer contains water that flows naturally between the States. Observing that all the cases of equitable apportionment had concerned such water (Kansas v. Colorado, 1907 SCC OnLine US SC 131), or fish that live in it (Idaho ex rel. Evans v. Oregon, 1983 SCC OnLine US SC 143), the Bench rejected Mississippi’s suggestion that the Middle Claiborne Aquifer was distinguishable from interstate rivers and streams because its natural flow is “extremely slow”. The Bench stated, “we have long applied equitable apportionment even to streams that run dry from time to time”. (Kansas v. Colorado, 1907 SCC OnLine US SC 131)
On Plea of Sovereign Ownership
Mississippi contended that it has sovereign ownership of all groundwater beneath its surface, so equitable apportionment ought not apply. Rejecting the aforesaid argument, the Bench stated that it is certainly true that “each State has full jurisdiction over the lands within its borders, including the beds of streams and other waters” but such jurisdiction does not confer unfettered “ownership or control” of flowing interstate waters themselves. And when a water resource is shared between several States, each one “has an interest which should be respected by the other.” (Wyoming v. Colorado, 1922 SCC OnLine US SC 129). Thus, the Bench denied the proposition that a State may exercise exclusive ownership or control of interstate “waters flowing within her boundaries.”
Verdict
In the light of the above, the Bench held that waters of the Middle Claiborne Aquifer are subject to the judicial remedy of equitable apportionment. Accordingly, Mississippi’s request for certiorari was declined. [Mississippi v. Tennessee, 595 U. S. ____ (2021), decided on 22-11-2021]