Last November, the Supreme Court of the United States decided, in a case of first impression for the Court, whether equitable apportionment applied to interstate aquifer disputes.[1]  Although the Court had never applied equitable apportionment directly to an interstate aquifer, the Court does have long-standing precedent concerning the reasonable allocation of other interstate waterways.[2]

THE MIDDLE CLAIBORNE AQUIFER

The case began in 2014 when the Court granted Mississippi leave to file a bill of complaint against Tennessee.[3]  However, the history of the case stretches much farther back in time.  Since its discovery in 1886, the Middle Claiborne Aquifer has provided the City of Memphis with safe drinking water.[4]  Not only does the aquifer flow under Tennessee, but the aquifer also flows beneath seven other states, including Mississippi.[5]

Aquifers are formed from groundwater that percolates through layers of rock, clay, and other materials under the Earth’s surface.[6]  In order to extract water from the aquifer, public utilities use wells to pump water from the aquifer below to the surface.[7]  For example, Memphis Light Gas Water Division (“MLGW”), the public utility in Memphis, pumps about 120 million gallons of groundwater from the Middle Claiborne Aquifer daily using wells near the Mississippi river.[8]  While the pumping of water provides many Memphians with an abundant amount of clean water, it also lowers water pressure at the site of the well and within the aquifer.[9]  This lowered water pressure has led to a “cone of depression” in both Memphis and DeSoto County, Mississippi.[10]

HISTORY OF THE CASE

Mississippi first sued the City of Memphis and MLGW in 2005 in Federal District Court, alleging that Memphis had unlawfully taken groundwater that rightfully belonged to Mississippi.[11]  The lawsuit–seeking at least 615 million dollars in damages and injunctive relief–argued, under property and tort law, that Mississippi “exclusively owned” all the water underneath the state.[12]  Although the district court acknowledged there was no precise precedent for ruling on the case, the court held that it would be prejudicial to Tennessee to render a judgment in the state’s absence.[13]  Therefore, the court determined that the State of Tennessee was an indispensable party and dismissed the case without prejudice.[14]

Although the federal district court never answered the question of whether an interstate aquifer, like other interstate waterways, is governed by the doctrine of equitable apportionment, the court acknowledged that the doctrine has been applied to similar case law in the past.[15]  The Supreme Court first created the idea of equitable apportionment in 1907, and has applied the doctrine to every shared interstate waterway, unless a statute, compact, or prior apportionment control exists.[16]   Equitable apportionment applies in cases where one state sues another due to an interstate dispute over water rights under the Supreme Court’s original jurisdiction.[17]  However, because Mississippi sued the City of Memphis and MLGW–instead of Tennessee–the federal district court had to dismiss the case.[18]  Finally, in 2014 Mississippi filed suit under the Supreme Court’s original jurisdiction against Tennessee, the City of Memphis, and MLGW, arguing Tenneessee’s water pumping amounted to a tortious taking of water that Mississippi rightfully owned.[19]

EXCLUSIVE OWNERSHIP V. EQUITABLE APPORTIONMENT

The Court appointed Judge Eugene E. Siler, Jr. of the Sixth Circuit to serve as Special Master for the case.[20]  Judge Siler determined that the interstate aquifer should be treated the same as any other interstate water resource, making equitable apportionment the appropriate remedy.[21]  Because Mississippi claimed exclusive “ownership” of the water beneath the surface of its state boundaries–instead of equitable apportionment–Judge Siler was left with no other option but to recommend the case be dismissed.[22]  Despite this decision, Judge Siler did recommend that Mississippi be granted leave to amend its case, to allow the state to argue for equitable apportionment.[23]  Upon reviewing Siler’s report, the Court agreed, and held that equitable apportionment was the only appropriate remedy.[24]  Yet, because Mississippi did not ask for equitable apportionment, the Court dismissed the case without leave to amend in a unanimous decision.[25]

While the Court accepted the argument that a state can regulate any surface waterway within its own boundaries, the Court held that Mississippi cannot claim “sovereign ownership of all groundwater” underneath the surface of the state.[26]  At first glance, this holding seems unreasonable.  However, the Court determined that the groundwater in the case was not exclusively under Mississippi, but instead part of an interstate aquifer that stretches between eight different states.[27]  Similar to case precedent in the past, although states are given the right to control rivers, streams and other waterways within the boundaries of the state, the state cannot completely cut off the flow of a waterway into another state.[28]  If the Court accepted Mississippi’s argument of exclusive ownership of the groundwater beneath its state, the Court would be setting the precedent that an upstream state can completely cut off the flow of a waterway to a downstream one.  This argument directly contradicts the equitable apportionment doctrine that allows for equal use of an interstate resource by the states that share it. 

Mississippi mainly relied on Tarrant Re’l Water Dist. v. Herrmann, arguing that this case supports its ownership argument.[29]  Yet the Court disagreed, delineating that the case only gives states the “authority to control their waters,” instead of complete ownership.[30]  Furthermore, the situation in Tarrant should not apply because the cases are too different.[31]  In Tarrant, not only was an interstate compact in place so equitable apportionment did not apply, but the case also arose from a party crossing jurisdictional lines to divert water away from another state.[32]  In Mississippi, the parties did not have an interstate compact in place, and Tennessee did not cross state lines to extract water from the aquifer.[33]  Instead, MLGW used wells within its own state to pump water from the aquifer to the state’s surface.[34]

Not only would ruling in favor of Mississippi create confusion in jurisdictions across the state, but it also would create consequences in the future.  Allowing a state to have exclusive ownership of waterways that flow into other states could lead states to unreasonably withhold water from other states.  This tragedy of the commons situation would create issues for both the citizens of impacted states, as well as their environments.  Therefore, because Mississippi argued that they were entitled to the exclusive ownership of the water within its state, the Court easily dismissed the case.[35]

Although Mississippi v. Tennessee seems like a relatively open and shut case, the case has significant ramifications beyond the states that share the Middle Claiborne Aquifer.  Despite taking up a very small portion of the opinion, the Court stated that the waters contained within the Middle Claiborne Aquifer are “subject to equitable apportionment.”[36]  Thus, the Court’s ruling sets the precedent for all interstate aquifers across the United States (not subject to any other prior agreement).  As long as a state’s water pumping from a shared aquifer is reasonable, the state will be allowed to continue using the aquifer.  Like many other environment doctrines, the term “reasonable use” is often given broad discretion.[37]  In this case, however, the Court did not have to determine whether MLGW’s pumping of about 120 million gallons of water daily–leaving a cone of depression in northern Mississippi–was a reasonable use.

Whether it was ambition or greed, Mississippi chose to sue Tennessee under property and tort claims, arguing full and exclusive ownership of the Middle Claiborne Aquifer.  Mississippi likely based this decision on the potential prize that would have resulted if the state’s claim was successful.  First, Mississippi sued Tennessee under a tort claim to receive monetary damages.  Under the equitable apportionment doctrine, the Court has declined to give monetary damages for past actions by offending states.[38]  So, if Mississippi wanted to receive monetary damages, they had to sue under a tort claim.  Despite this high price tag likely looking appealing to Mississippi, successfully winning this argument would have far reaching consequences across the country. Allowing states to suddenly bring claims for damages against other states for past uses of an interstate aquifer would give rise to lawsuits for astronomical damages across the country.   Second, Mississippi sued under a property claim to receive injunctive relief.[39]  Regardless of whether the Court awarded damages, suing for injunctive relief would force Tennessee to stop pumping water from the Middle Claiborne Aquifer.  Granting this argument would relieve the cone of depression under Northern Mississippi, however it would also force MLGW and the City of Memphis to find a new water supply.  Similar to the Court awarding damages to Mississippi, ruling in favor of the Plaintiff for injunctive relief would create water supply issues for any city that pumps water from an interstate aquifer.  Therefore, although a successful claim for damages and injunctive relief likely persuaded Mississippi to sue under a property and tort arguments, the lawsuit had little chance of being successful.

The argument can be made that MLGW’s decision to pump about 120 million gallons of water daily–leaving a cone of depression in Northern Mississippi–was, in fact, not a reasonable use.  So, why did Mississippi specifically argue against equitable apportionment?  In the Court’s first equitable apportionment case, Kansas v. Colorado, the Court stated the equitable apportionment doctrine considers “equality of right;” not the equality of the amount of water given to each state.[40]  Since this case, the Court has developed a test for determining whether a party deserves apportionment.[41]  After a party has proved standing, the complaining state must then show a real and significant injury, and that the injury “substantially outweigh[s]” the benefit given to the other state.[42]  Although Mississippi would have been able to show standing, as well as a significant injury, the case would likely come down to this balancing test.[43]  One factor the Court considers when looking at this balancing test is existing uses.[44]  In this case, Tennessee has used water from this aquifer for almost one hundred and fifty years.[45]  Moreover, the City of Memphis likely has a claim that its existing use is more important for public health.  MLGW uses the aquifer to supply safe drinking water for the City of Memphis, while Mississippi uses the water mostly for agriculture.[46]  Thus, it is likely Tennessee would have still prevailed under this argument as well.

Ultimately, Mississippi’s decision to file suit against Tennessee in 2014 can be summed up with a baseball analogy.  Similar to a batter swinging for a homerun with two outs in the bottom of the ninth, Mississippi’s lawsuit had a strong likelihood of failure.  While swinging for a home run will yield the highest reward possible to the batter if successful, swinging for a base hit has a much higher success rate.  For Mississippi, although suing Tennessee under property and tort law gave the state the chance to receive millions of dollars in damages, suing for equitable apportionment gave Mississippi the best chance at fixing the problem.  Despite the Court likely holding that MLGW could continue to pump water from the aquifer, if Mississippi argued for equitable apportionment the Court might have regulated MLGW’s pumping from the aquifer.  Not only would this potentially relieve the cone of depression in Northern Mississippi, but it would also guarantee Mississippi a reasonable allocation of water from the aquifer.