The decades of compacts, laws, contracts and regulatory guidelines that are supposed to manage bordering states’ use of the Colorado River have come to be known collectively as the "Law of the River."
But it could soon bump up against the laws of physics, according to a report from the Cronkite News Service.
Ninety years after the first agreements were drawn up and more than 50 years after the Supreme Court set water-use levels for Arizona and its neighbors, demand for Colorado River water continues to grow. But the amount of water flowing in the river and the allotments of it to different users remains the same.
In 2011, Arizona used more than 99 percent of its allotted 2.8 million acre-feet of water for homes, crops, recreation and businesses across the state.
Add to that demand a proposal in Washington to allocate 20,000 acre-feet of river water to the Navajo and Hopi tribes, and the state is bumping right up against the limit, if not going slightly over it.
Trying to squeeze every last sanctioned drop from the exhausted river has an effect up and down the Colorado, from the reservations upstream to the croplands 1,000 miles downstream.
“If it wasn’t for water in this area, [farmers] wouldn’t be farming here,” said Ed Carpenter, manager at the Yuma County Water Users’ Association. “So here, water is everything.”
By the time it reaches Carpenter’s farmers, the water in the Colorado River has already made a long journey from its sources in the snow-capped Rocky Mountains.
If left untouched by man, the river would deliver about 16.5 million-acre feet of water to the Gulf of California annually. But today only a fraction of that amount reaches the gulf.