Sitting, as it were, as an international as well as a domestic tribunal, we apply Federal law, state law, and international law, as the exigencies of the particular case may demand . . .
The United States Supreme Court has heard 137 cases under its Original Jurisdiction. Kansas v. Colorado (Original No. 105), like many of its sister original jurisdiction disputes, dealt with an interstate water dispute. Indeed, the case involves a problem that has bedevilled the American west for over one hundred years: the apportionment of river water, mostly for irrigation purposes, in a desert to semi-desert environment.
In adjudicating inter-state water disputes, the Supreme Court’s first legal duty and challenge – like that of all international courts and tribunals – is to balance the competing interests of state sovereignty. Kansas v. Colorado demonstrates these competing interests in the guise of water allocation and the rough and tumble wrangling between the litigants over water. The dispute also demonstrates the lengths to which states situated in the arid west will go for a greater share of the existing pool of water. For example, Kansas sued Colorado numerous times without success, claiming that the latter was depriving it of its ‘rightful’ share of river water. Another excellent example of this ‘hunger’ for water and the jealousy state sovereignty engenders is demonstrated by another of the Court’s disputes, Arizona v. California, where California fought a decades-long rancorous dispute with Arizona, over 548 ac-ft (675 947 m3) of water/day, or 200 000 acre-feet (246 696 000 m3) of water annually. But, this appetite for the allocation of water was and is not limited to the United States. It is also a current phenomenon in India’s Sutlej and Krishna Rivers, Bangladesh, and South Africa.
With regards to the issue of state sovereignty, it has been a constant in the United States’ Supreme Court’s transboundary dispute portfolio for almost one hundred years. Indeed, in 1931, Justice Oliver Wendell Holmes observed, in New Jersey v. New York that the competing interests of state sovereignty must be balanced where an upper riparian has the physical power to cut off all the water within its jurisdiction, to the lower riparian. Moreover, he also observed that:
<quotation>the exercise of such a power to the destruction of the interest of lower [riparian] States could not be tolerated. And on the other hand equally little could New Jersey be permitted to require New York to give up its power altogether in order that the river might come down to it undiminished. Both States have real and substantial interests in the River that must be reconciled as best they may be. </quotation>
The foregoing speaks not only to the Court’s balancing of state sovereignty interests, but also to its consideration of the ‘community of interests’ between states, in the use of water from their transboundary river.
It is telling that after all these years, the notion of ‘community of interest’ is the current trend in water allocation and appears to be the future direction in which the law and practice in the apportionment of water is traveling. In the modern era, the concept stems from the sense that a community of interest in a transboundary river’s water is shaped by the fact that it is part of the commons or, a common property, and ought to be shared by the community. It also captures the view of a watercourse as part of a wider hydrological system and suggests collective action when administering it. Similarly, the community of interest embraces a more exacting theory of the sovereign relationships of the States.
The paramount importance of the sovereignty issue means that it casts a long shadow over the Court’s adjudication. Consequently, the artifact of federalism is always in the background of the Court’s adjudication of intra-state water disputes. Similarly, in a union of states, such as the European Union, sovereignty is also a key aspect for the members of the union. As Joseph H.H. Weiler has observed, ‘Europe has charted its own brand of constitutional federalism.’
2. THE AMERICAN WEST AND THE WATER PARADOX
The American West is an arid region. In order to understand the underpinnings of the Kansas v. Colorado dispute, some historical perspective is necessary. In 1893, Maj. John Wesley Powell, the explorer who opened up the West declared:
<quotation>When all the rivers are used, when all the creeks in the ravines, when all the brooks, when all the streams are used, when all the reservoirs along the streams are used, when all the canyon waters are taken up, when all the artisan waters are taken up, when all the wells are sunk or dug that can be dug in all this arid region, there is still not sufficient water to irrigate all this arid region . . . Not one more acre of land should be granted to individuals for irrigating purposes. </quotation>
Powell underscored the fact that in the western United States water is life. However, for over 170 years both the federal and state governments have been attempting to fool Mother Nature. In some ways, they have succeeded. Nevertheless, given the continuing droughts over the past decade, the notion of control over water resources was at best illusory.
Returning to the earlier period, beginning in the 1840s the United States Government provided exclusive rights to people who were willing to farm the land in states like Kansas, Nebraska and Wyoming. Although most eastern politicians and government officials had never been west of St. Louis, they believed that eastern and western European farming methods were appropriate for the areas west of the 100th meridian, which represents the separation between the moist east and the arid west. However, this was and is not the case. The homesteaders, who flocked to the west on promises of rich soil and sufficient water resources were fooled by the federal government and local entrepreneurs. Many of these homesteaders were immigrants who were recruited to move west – and to extend the European hold on these lands – so that they might prosper and make their fortunes. Of course, these people were entirely unaware of the fact that the region encompassing Colorado, Kansas, Nebraska and Wyoming, among other states, was extremely arid, receiving approximately 38 cm (15 inches)–48 cm (19 inches) of rain per year, in contrast to the 102 cm–152 cm (40–60 inches) average that fall from Virginia northwards, and to what many of these settlers were used to in Europe. Many of them perished from hunger or lost whatever money they had and returned east.
When the western and southwestern states were settled, the settlers quickly learned that the farming methods they brought from Europe were utterly unsuitable because there was a paucity of water. Accordingly, in order to cultivate crops they needed irrigation and, just as was done in ancient Mesopotamia, water had to be channeled and diverted from a river to cultivate crops. When Kansas v. Colorado was filed in the Supreme Court, as is true today in these agrarian lands, water equalled money, in state revenue and revenue for the citizens who farmed the land and others who provided services to farmers, i.e. water was and is the lifeblood of the economy. Therefore, states were extremely jealous and combative of and about the apportionment of water from their transboundary river. Indeed, Kansas not only had water disputes with Colorado over water allocation, it also sued other states, including Nebraska, its neighbour to the north, and Wyoming, its neighbour to its northwest, seeking greater appropriative rights. Similarly, Wyoming sued Colorado, its neighbour to the south, over appropriative water rights.
Today, as has been true for decades, the importance of water as a resource is demonstrated by the fact that every southwestern and western state has a water court and a state water engineer. One thing is certain, these types of dispute will continue to flare-up in this region and around the world, because of global warming and climate change.
3. KANSAS V. COLORADO
Kansas v. Colorado commenced in 1901 and concluded in 2009, an epoch of 108 years. The dispute centered upon the allocation of the waters of the Arkansas River between irrigators on either side of the border. In the Court’s 1907 decision – the second in the dispute – Justice David Brewer was confronted with two different water norms: Colorado subscribed to the first in time, first in right, or the prior appropriation western water law doctrine, while Kansas maintained the common law riparian rights system of water allocation, the Court established a Solomonic doctrine: equitable allocation of water between the two states. The doctrine was developed in order to resolve this water allocation dispute located in this semi-desert agricultural environment and, clearly, the law was utilized as a means of pacific dispute resolution, i.e., use of the courts, as opposed to turning to armed conflict.
Brewer also developed the concept of ‘equality of right’, which refers to states’ equal standing in their sovereign power and right. In attempting to reconcile the common law, international law and dispute resolution, the Justice observed that:
<quotation>For after all, the common law is but the accumulated expressions of the various judicial tribunals in their efforts to ascertain what is right and just between [parties] . . . We have exercised that power in a variety of instances, determining in the several instances the justice of the dispute. Nor is our jurisdiction ousted, even if, because Kansas and Colorado are States sovereign and independent in local matters, the relations between them depend in any respect upon principles of international law. International law is no alien in this tribunal.</quotation>
The foregoing set the stage for many of the Court’s subsequent equitable apportionment cases, including two of its most recent ones, 2010 North Carolina v. South Carolina, and 2015 Montana v. Wyoming. Indeed, there was an essential need for a structure to replace ‘the waging of war and to negotiating treaties’, which would allow for the pacific resolution of disputes, while according the respect and dignity due to the sovereignty and equality of each State. Moreover, some years later, in Wyoming v. Colorado Justice Van Devanter hailed the doctrine of equitable allocation as ‘a pioneer in its field’.
The gravamen of Kansas’ claim, was that Colorado acting as parens patria and on behalf of a number of corporate irrigation companies, deprived and threatened to deprive the State of Kansas and its citizens of the water that naturally and habitually flowed in the Arkansas river from Colorado to Kansas Nevertheless, the allocation formula that the Court inaugurated back at the turn of the last century was fashioned for an agrarian society, and focused on apportioning the water for one purpose: irrigation.
 Kansas v. Colorado, 206 U.S. 46, 97 (1907). (Emphasis added).
 The Court was provided with the jurisdiction to hear disputes between the states of the Union, by the Constitution’s Article III and the Judiciary Act of 1789. The Court’s original jurisdiction provides, for our purposes, ‘the Supreme Court shall have original and exclusive jurisdiction of all controversies between two or more States . . .’ Thus, the Court sits as a trial court or a quasi international court when it hears disputes between the states.
 See e.g., Itzchak E. Kornfeld, ‘Is News of “Sovereignty’s Death” Exaggerated?’ 18 ILSA J International & Comparative L (2012), 315; Noah Hall, ‘Bilateral Breakdown: U.S.–Canada Pollution Disputes’ (2006) 21 Nat. Resources & Envt, 18, 68.
 An acre-foot of water is the quantity of water required to cover an acre to a depth of one foot, which converts to 43 560 cubic feet. 548 ac-ft/day converts to 222 hectares/day. The following conversion rates were used: one acre = 0.405 hectares. That is: 178 566 567 gallons, or 678 552 122 litres.
 K.S. Murty, ‘River water sharing: India’s problems, FRIEND 2002 − Regional Hydrology: Bridging the Gap between Research and Practice’ (Proceedings of the Fourth International FRIEND Conference held at Cape Town, South Africa. March 2002). IAHS Publ. no. 274. 2002, <http://hydrologie.org/redbooks/a274/iahs_274_323.pdf> accessed 17 January 2017.
 Robie I. Samanta Roy, Trade and Environment Data Base, India-Bangladesh Water Dispute, ICE Case Number 78 (1997) <http://www1.american.edu/ted/ice/indobang.htm> accessed 17 January 2017 (‘The problem of water resource allocation and sharing, primarily for irrigation purposes, has plagued relations between India and its neighbors . . . as well as the . . . water allocation issues associated with the Ganges river system.’)
 Synne Movik, The Dynamics and Discourses of Water Allocation Reform in South Africa, STEPS Working Paper 21, Brighton: STEPS Centre (2009), <http://steps-centre.org/wp-content/uploads/Reform_web_version.pdf> accessed 17 January 2017. (‘The increasing perceptions of water scarcity have prompted many countries to engage in reforming their water legislations and systems of water use rights.’)
 283 U.S. 336 (1931).
 Ibid., 342–3. (Emphasis added.)
 See generally, Alistair Rieu-Clarke, R. Moynihan and B. Magsig, ‘UN Watercourses Convention − User’s Guide’ (2012), 103–105 <http://www.unwatercoursesconvention.org/documents/UNWC-Fact-Sheet-10-Theories-of-Resource-Allocation.pdf> accessed 17 January 2017.
 The sovereignty issue plays out as follows inside a federal state: The U.S. Constitution’s Bill of Rights’ 10th Amendment states that: ‘The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.’ Thus, there exists a continuous interplay between state and federal sovereignty, and in Congress the issue of states’ rights versus federal rights.
 Joseph H.H. Weiler, ‘Federalism without Constitutionalism, Europe’s Sonderweg’ in Kalypso Nicolaidis and Robert Howse (eds), The Federal Vision: Legitimacy and Levels of Governance in the United States and the European Union (Oxford University Press 2001), 70.
 Maj. John Wesley Powell speaking extemporaneously at the Second International Water Irrigation congress in Los Angeles, in mid-October 1893, quoted in Jonathan Waterman, Running Dry: A Journey from Source to Sea Down the Colorado River (National Geographic, 2010) 242. (Emphasis added).
 The Homestead Act of 1862, Act of May 20, 1862, Public Law 37–64, enacted during the Civil War, provided, among other benefits, that any adult citizen, or future citizen, i.e., European settlers, who had never borne arms against the United States, which excluded Confederate soldiers, would be granted plots of 160 acres of government surveyed land, if he or she paid a $10 fee, lived on the land for five years and ‘improved’ the parcel by constructing a dwelling building and cultivating the plot. After five years the original patent holder or filer, was entitled to a fee simple deed. Homestead Act (1862), Ourdocuments.gov (1995), <https://www.ourdocuments.gov/doc.php?flash=true&doc=31> accessed 17 January 2017.
 United States Department of the Interior, United States Geological Survey, Nationalatalas.gov, Colorado, Precipitation (2011), <https://nationalmap.gov/small_scale/printable/images/pdf/precip/pageprecip_co3.pdf> accessed 17 January, 2017. (‘The average annual precipitation for Colorado is 15.47 inches.’)
 The average rainfall in Virginia for the period 1895–1998 was 42.7 inches. See Bruce P. Hayden and Patrick J. Michaels, Virginia’s Climate, University of Virginia Climatology Office (2000) <http://climate.virginia.edu/description.htm> accessed 17 January 2017.
 See generally, Marc Reisner, Cadillac Desert: The American West and Its Disappearing Water (Penguin Publ., revised edn 1993) and James Malin, Winter Wheat in the Golden Belt of Kansas (University of Kansas Press, Lawrence Kansas1944).
 Kansas v. Colorado, 538 U.S. 720 (2003).
 See e.g., Colorado State Judicial Branch, Water Courts (2011), <http://www.courts. state.co.us/Courts/Water/Index.cfm> accessed 17 January 2017.
 See generally, Kansas Dept. of Agriculture, Division of Water Resources (2011), <http://www.ksda.gov/dwr> accessed 17 January 1917. (‘The Division of Water Resources administers 30 laws and responsibilities including the Kansas Water Appropriation Act which governs how water is allocated and used; statutes regulating the construction of dams, levees and other changes to streams; the state’s four interstate river compacts; as well as coordinating the national flood insurance program in Kansas.’)
 185 U.S. 125 (1902).
 556 U.S. 98 (2009).
 206 U.S. 46 (1907).
 Kansas v. Colorado, 206 U.S. 46, 98. ‘One cardinal rule underlying all the relations of the states to each other is that of equality of right. Each state stands on the same level with all the rest. It can impose its own legislation on no one of the others, and is bound to yield its own views to none . . . the question of the extent and the limitations of the rights of the two states becomes a matter of justiciable dispute between them, and this Court is called upon to settle that dispute in such a way as will recognize the equal rights of both, and at the same time establish justice between them’.
 Ibid., 97.
 Ibid. (Emphasis added).
 No. 138 Original, South Carolina v. North Carolina, 558 U.S. 256 (2010).
 No. 137 Original, 577 U. S. ____ (2016).
 Kristin L. Myles, ‘South Carolina v. North Carolina – Some Problems Arising in an East Coast Water Dispute’ (2012) 12 Wyoming Law Review, 3, 5.
 259 U.S. 419 (1922).
 Ibid., 464.
 206 U.S. 46, 47–8 (1907).
 Professor Gabriel Eckstein has noted that ‘the formula of equitable apportionment is rather generic and that its application in 1907 focused on agriculture simply because the dispute centered on agriculture.’ (Personal communication 11 September 2015). Indeed, the doctrine has been utilized in other factual scenarios. See e.g., North Carolina v. South Carolina 558 U.S. 256 (2010) (drinking water). Nevertheless, the Supreme Court has yet to apply its allocation formula for multiple uses or solely for nature.