It's caused international incidents with border flair. A Mexican governor has villified Texas leaders for playing politics with it and U.S. lawyers have threatened to sue for violation of international treaties related to it. Steeped in the annals of America's symbiotic relationship with Mexico is the two countries’ long-standing and sometimes tense agreement over an issue more far-reaching than border security and immigration: water.
The Treaty of Feb. 3, 1944 — also called the “Treaty of the Utilization of Waters of the Colorado and Tijuana Rivers and of the Rio Grande” — directs Mexico to deliver water to the U.S. from six tributaries that feed into the Rio Grande, in exchange for water from the Colorado River. But the Mexican government's inability to meet its current water obligation has some Texas businesses, agricultural leaders and state lawmakers keeping a close eye on their southern neighbor.
The treaty, which runs in five-year cycles, mandates that Mexico deliver an average of 350,000 acre-feet of water to the U.S. annually from the waters that flow into Mexico's Rio Grande, known there as the Rio Bravo. In exchange, Mexico is entitled to 1.5 million acre-feet of water annually from the Colorado River, which drains into Mexico at the Arizona-California border. (An acre-foot of water is 325,821 gallons.) But in the first year of the treaty's current cycle, which ended Feb. 28, Mexico delivered just 189,371 acre-feet of water to the U.S. — well short of the expected annual average.
Sally Spener, public affairs officer with the El Paso-based International Boundary and Water Commission (IBWC), said this doesn't present a crisis yet; the treaty was authored in a fashion that allows Mexico to make up the difference. Mexico could make up last year’s deficit by releasing about 510,600 acre-feet by the end of February 2011. “The reason the treaty did this is, that particular region is affected by highly variable conditions, so that you can have low flow one year and you can have a hurricane the next,” Spener said. “That’s why it is a five-year average that is required rather than an annual delivery amount.”
Some critics have less confidence. They point to Mexico’s past delivery troubles, including a feud the country settled with U.S. farmers in 2005, after Mexico fell behind in its delivery by more than 700,000 acre-feet. At the time, Mexican authorities said their own water needs were preventing the release. After Mexico agreed to expedite delivery the dispute ended — but the aftereffects still linger.
The treaty directs water use in Texas from Fort Quitman to the Gulf of Mexico, and has a huge impact on Texas agricultural producers and municipal water suppliers who rely on the river or their water. The majority of water delivered to the U.S. comes from two main tributaries that feed into the Rio Grande: the Conchos, which enters the river in Presidio and in Ojinaga, Mexico; and the Salado, which enters the Rio Grande at the Falcon Dam reservoir, which sits on the Starr/Zapata county line south of Laredo.
At a recent interim committee hearing of the Texas Senate’s International Relations and Trade Committee at the Capitol, Texas Commission on Environmental Quality officials explained that Mexico is not in violation of the treaty — yet. “It is something that we have brought to the attention of the IBWC and have scheduled a meeting with the State Department,” testified Carlos Rubinstein, a TCEQ commissioner. “Anything that impacts the delivery of water to the Rio Grande ultimately impacts the delivery of water to all of the residents and could also impact the colonias.”
Ken Jones, the director of the Lower Rio Grande Valley Development Council, explained that Mexico holds the cards in the situation, at least geographically. “Seventy-eight percent of the watershed that feeds into Falcon and Amistad that supplies the water for the U.S. side is actually physically in Mexico,” he said. “That’s why the compliance thing is so important to us because it’s limited access to the U.S. side in terms of inflow to the reservoir system.”
What do the Mexicans say when asked about their shortfall? "They say they need if for their side, too," said Jones.
Most of the Mexican water is used for irrigation in Texas. Rio Grande Valley Water Master Erasmo Yarrito, who calculated water use percentages for this story, said since at least 2007, the majority of the area’s water was used for irrigation — about 72 percent that year, rising to about 80 percent in 2008 and 2009.
Jones said reservoir levels are monitored on a regular basis to check the inflow of water from Mexico. The situation with Mexico was dire last time, not only because of the backlog, but because of the simultaneous drought experienced by the region. But the reservoirs are currently at greater than 80 percent capacity this time around — a good sign. Jones said it isn't until reservoir levels reach the 50 to 55 percent capacity range that municipalities initiate local water restrictions.
Rubenstein said the impact of the Mexican water shortfall is "primarily to agricultural users, but that then translates into an economic impact to the Valley as well." Because 100 percent of water-supply corporations and municipalities in the Rio Grande Valley get their water from the Rio Grande, Rubinstein added, “if the river is short-changed, it will affect just about every sector of the Valley.”
“We are continuing to work with them," Rubenstein said. Mexico "fully caught up [in the past] and were actually able to close two cycles.”