Modern-Day Rio Grande Water Wars : Border: Texans are outraged that Mexican farmers are siphoning off the scarce resource. Mexico blames the drought, while Texas says the problem is its neighbor’s poor planning.

Texas farmers, river rafters and environmentalists are frothing over a Rio Grande water shortage caused by Mexican farmers upstream siphoning off the scarce resource.

Thousands of farmers in northern Mexico are struggling through a three-year drought that has killed 300,000 cattle and withered nearly a million acres of crops. The Mexican government says it needs the water to prevent further devastation.

But critics on both sides of the border say Mexico’s problems spring from poor planning. When Mexican officials made a request to the U.S. State Department for a water loan last month, Texas Gov. George W. Bush was quick to oppose it.

“Texas will not support a loan of Texas water to Mexico, as this would jeopardize the welfare of many of our citizens,” the governor wrote in a May 4 letter to the International Boundary & Water Commission, a joint U.S.-Mexican monitoring agency. Growers in the Texas Rio Grande valley, who produce more than $300-million worth of citrus, sugar cane and vegetables, depend heavily on the river for irrigation, he said.

Since the two neighbors signed a treaty in 1944, Mexico and the United States have shared the use of water from reservoirs along the Rio Grande. This year, Mexico had used 90% of its allotment by mid-May.

Texas farmers are not in bad shape yet, said Bill Weeks of the Texas Citrus and Vegetable Assn. in Harlingen. “But if we don’t get some rain over the next few months, we will be in trouble.”

Rafting outfitters near Big Bend National Park have been less fortunate. “We’re doing less than one-tenth of what we usually do,” said Pierre de Koninck, who runs a river shuttle service in Terlingua, Tex. Some river outfitters have closed shop and moved to Colorado for the summer.

The river is at the “beginning of a crisis,” said Salvador Contreras, a recently retired conservation biologist at the University of Nuevo Leon in Monterrey, Mexico.

The drought is exacerbating salinity problems in the Rio Grande, killing fish and other fauna that live in the river. “And it will get worse as more and more water in the middle part of the river is used in agriculture,” Contreras said.

Most of the water is drawn from two lakes: Amistad Reservoir and Falcon Reservoir. Because each nation takes as much as it contributes each year in runoff, the United States has 1.7 million acre-feet of water in the lakes. Mexico has about 113,000 acre-feet. That’s enough water for domestic and municipal needs, said Texas Secretary of State Tony Garza, but not enough for Mexico’s agricultural needs.

Still, Texas opposition to a water loan may do little to stop Mexican farmers from helping themselves. There have been many reports of illegal pumping, but the boundary commission has no law-enforcement personnel.

The current drought highlights the lack of a regional water policy, which may soon brake the explosive economic development along the border. “Demands on the water supply have grown exponentially,” Garza said, “while the supply has remained level.”