Dividing the water at Fort Quitman : a discussion of binational allocation and dynamic treaty interpretations

This report discusses the binational water allocation of the Rio Grande between the United States (U.S.) and Mexico. The International Boundary and Water Commission, United States and Mexico (IBWC) is charged with the administration and enforcement of treaties and other international agreements governing this watercourse, including but not limited to the Convention of 1906 and the Treaty of 1944. These two treaties establish an upper and lower segment of the Rio Grande. The 1906 Convention allocates water to Mexico and the U.S. in the transboundary segment from El Paso to Fort Quitman, about 90 miles away. The 1944 Treaty governs the watercourse from Fort Quitman to the Gulf of Mexico. Water allocation at Fort Quitman is indefinite in these treaties because the location represents a “terminus” point of the two segments. A plain-language interpretation of the treaties indicates the flows reaching this gage actually belong 100 percent to U.S., and therefore to Texas water rights holders, due to a waiver of rights by Mexico in the 1906 Convention for all flows in the upper segment. However, the established practice of the IBWC since the 1950s is to allocate those waters equally between Mexico and the U.S. (“50/50”). Research into IBWC materials reveals that this 50/50 allocation practice was established ad-hoc. There is no diplomatic evidence of agreement between the nations to justify the 50/50 allocation. Indeed, the current allocation practice at Fort Quitman contradicts the actual treaty text. The IBWC has not exercised its authority to establish the 50/50 allocation lawfully. Recommendations to remedy the matter include returning all the flows at Fort Quitman to the U.S. and Texas, to mandate the 50/50 practice through legal and diplomatic policy-making mechanisms. Another issue is whether Mexico ought to compensate the U.S. for the 2.1 million acre-feet it has received since the informal water allocation began in 1958 in contradiction to the treaties.