This includes oversight of IBWC's actions to manage the Colorado River's water and infrastructure to improve water availability during drought and to restore and protect riverine ecosystems. On multiple occasions since 1994, Mexico has not met its Rio Grande water delivery obligations to the United States within the five-year period prescribed by the 1944 Water Treaty. Since 2014, Congress has directed the U.S. Department of State to report annually on Mexico's deliveries and on efforts to improve Mexico's treaty compliance. In the 1944 Water Treaty, the United States and Mexico allocated water in the Rio Grande basin below Fort Quitman, TX, and in the Colorado River basin; they also authorized the IBC to oversee U.S.-Mexico water-allocation treaties, renaming it the IBWC. The Minute Process

The 1944 Water Treaty authorizes the IBWC to develop rules and to issue proposed decisions, called minutes , regarding matters related to the treaty's execution and interpretation. Water Delivery Requirements Established in the 1944 Water Treaty

The 1944 Water Treaty defines the basic water-distribution arrangements between the United States and Mexico as
For the Colorado River basin, the United States provides Mexico with 1.5 million AF of water annually. Key elements of the agreement included the following: 
extending provisions of Minute 318 (Cooperative Measures to Address the Continued Effects of the April 2010 Earthquake in the Mexicali Valley, Baja California) to allow Mexico to defer delivery of its Colorado River water allocation while the country repairs earthquake-damaged infrastructure; delivering additional water (i.e., above the 1.5 million AF annual delivery required by the 1944 Water Treaty) to Mexico when water levels are high in Lake Mead; reducing deliveries to Mexico during water shortage conditions in the Colorado River basin (i.e., Mexico's annual water deliveries would be reduced if Lake Mead elevations indicated shortage conditions, similar to reduction by the U.S. lower basin states); creating a mechanism by which U.S. water deliveries to Mexico could be held in U.S. reservoirs for subsequent delivery; continuing to address salinity concerns per Minute 242; and implementing a pilot program of jointly funded water efficiency and conservation projects in Mexico. Rio Grande Basin

Water sharing in two portions of the binational Rio Grande basin has distinct characteristics. In the first year of the cycle, Mexico fell 15% below its water-delivery obligations under the 1944 Water Treaty. IBWC indicates that Mexico delivered to the United States less than 350,000 AF in the third year of the cycle. However, Mexico's higher deliveries in the second year resulted in cumulative deliveries for the first three years of the cycle being almost 98% of the three-year delivery target of 1.05 million AF. As part of its broader effort to improve the reliability in Mexico's water deliveries, the IBWC is developing a binational model for water management in the Rio Grande. The IBWC accounts for Mexico's deliveries to the United States pursuant to the 1944 Water Treaty largely by aggregating deliveries (i.e., 1.75 million AF) over a five-year cycle, with an annual average delivery target of 350,000 AF. To date, Congress has been involved in binational water-sharing issues primarily through oversight. For Congress, binational Colorado River oversight topics may encompass Minute 323 implementation and operations and deliveries during shortage conditions. It required that the Secretary of State report to the Committees on Appropriations on the following water delivery and accounting issues: 
Not later than 45 days after the enactment of this Act, the Secretary of State, in consultation with the Commissioner for the United States Section of the International Boundary and Water Commission (IBWC), shall report to the Committees on Appropriations on the efforts to work with the Mexico Section of the IBWC and the Government of Mexico to establish mechanisms to improve the transparency of data on, and predictability of, the water deliveries from Mexico to the United States to meet annual water apportionments to the Rio Grande, in accordance with the 1944 Treaty between the United States and Mexico Respecting Utilization of Waters of the Colorado and Tijuana Rivers and of the Rio Grande, and on actions taken to minimize or eliminate the water deficits owed to the United States in the current 5-year cycle by the end of such cycle: Provided, That such report shall include a projection of the balance of the water delivery deficit at the end of the current 5-year cycle, as well as the estimated impact to the United States of a negative delivery balance.
The United States and Mexico share the waters of the Colorado River and the Rio Grande. A bilateral water treaty from 1944 (the 1944 Water Treaty) and other binational agreements guide how the two governments share the flows of these rivers. The binational International Boundary and Water Commission (IBWC) administers these agreements. Since 1944, the IBWC has been the principal venue for addressing river-related disputes between the United States and Mexico. The 1944 Water Treaty authorizes the IBWC to develop rules and to issue proposed decisions, called minutes, regarding matters related to the treaty's execution and interpretation.
Water Delivery Requirements Established in Binational Agreements. The United States' and Mexico's water-delivery obligations derive from multiple treaty sources and vary depending on the body of water. Under the 1944 Water Treaty, the United States is required to provide Mexico with 1.5 million acre-feet (AF) of Colorado River water annually. The 1944 Water Treaty also addresses the nations' respective rights to waters of the Rio Grande downstream of Fort Quitman, TX. It requires Mexico to deliver to the United States an annual minimum of 350,000 AF of water, measured in five-year cycles (i.e., 1.75 million AF over five years). For waters of the Rio Grande upstream of Fort Quitman, a 1906 bilateral convention requires the United States annually to deliver 60,000 AF of water to Mexico.
Developments in the Colorado River Basin. The United States continues to meet its Colorado River annual delivery requirements to Mexico pursuant to the 1944 Water Treaty. At the forefront of recent IBWC actions on the Colorado River are efforts to cooperatively manage the Colorado River's water and infrastructure to improve water availability during drought and to restore and protect riverine ecosystems. Minute 323 is a set of binational measures in the Colorado River basin that provides for binational cooperative basin water management, including environmental flows to restore riverine habitat. Minute 323 also provides for Mexico to share in cutbacks during shortage conditions in the U.S. portion of the basin. Additionally, Minute 323 designates a "Mexican Water Reserve" through which Mexico can delay its water deliveries from the United States and store its delayed deliveries upstream at Lake Mead, thereby increasing the lake's elevation. Lake Mead elevation is the baseline used for determining shortage conditions and associated water delivery cutbacks for the lower Colorado River basin states of Arizona, California, and Nevada. Recent congressional attention to the Colorado River basin has related largely to oversight of Minute 323 implementation and water management during potential shortage conditions.
Developments in the Rio Grande Basin. On multiple occasions since 1994, Mexico has not met its Rio Grande delivery obligations within the five-year cycle established by the 1944 Water Treaty. For example, Mexico fell 15% below its water-delivery obligations under the 1944 Water Treaty for the five-year cycle from 2010 to 2015. Mexico addressed its deficit by early 2016. The October 2015 to October 2020 cycle is under way. Mexico offset its below-target deliveries for the first year of this cycle with additional deliveries in the second year. IBWC indicates that Mexico delivered less than its 350,000 AF in the third year of the cycle; however, higher deliveries in the second year resulted in Mexico's deliveries being almost at 98% of the three-year cumulative delivery target of 1.05 million AF.
Some U.S. stakeholders promote the adoption of mechanisms to achieve a water-delivery regime by Mexico that provides more reliability and benefit for U.S. interests in Texas. The IBWC is developing a binational model for water management in the Rio Grande, as part of its broader effort to improve reliability in Mexico's water deliveries. Congress has been involved in the recent Rio Grande water-sharing issues through oversight. Congress requires the U.S. Department of State to report annually on Mexico's deliveries and on efforts to improve Mexico's treaty compliance.