A planned, much-debated fence along the U.S.-Mexico border designed to keep people from crossing the Rio Grande could exacerbate flooding and skew the national boundary, a binational commission said Wednesday.
An impermeable fence anywhere between the river and levees, which can be as far as 1 1/2 miles from the river itself, could cause flooding in addition to violating a 1970 treaty, said Sally Spener, spokeswoman for the International Boundary and Water Commission.
The treaty declared the international boundary at the midpoint of the river and prohibited construction of anything that could deflect or obstruct the water flow and harm the other side.
“If you have a structure that is going to alter the river channel, then you are in effect altering the boundary between the United States and Mexico,” she said.
The United States and Mexico established the commission in 1889 to regulate water use and apply boundary treaties for the shared Rio Grande and Colorado rivers. Together, the commission has built and maintained international dams and reservoirs, hydroelectric plants, water treatment plants and floodway projects.
The commission is waiting for the government to submit proposals for the fence’s location and materials, Spener said.
Congress last year passed a law requiring about 700 miles of fencing along the 2,000-mile U.S.-Mexico border. Of the $1.2 billion Congress approved, at least $400 million has been released. The Department of Homeland Security has said it is committed to erecting 370 miles of fencing by the end of 2008.