Monday, August 18, 2014

Water in the West, Part 1: Getting thirstier as water supplies dwindle

With changes in climate, population and water resources upon us, there’s a sense among those working toward drafting the state water plan that the potential for a Colorado water catastrophe is real. That catastrophe could come in many forms, but the most feared is a curtailment of the Colorado River Compact of 1922. Seven states — Wyoming, Colorado, Utah, New Mexico, Arizona, California and Nevada — form the United States portion of the Colorado River Basin. Those seven states separated the basin into upper and lower regions under the compact, apportioning the water and mandating minimum average flows at the border that divides the Upper and Lower basins in Lee Ferry, Arizona. When the compact was signed in 1922, the flow of the river was estimated to be at least 17 million acre-feet, so 7.5 million acre-feet was apportioned to both the Upper and Lower basins, with the Lower Basin also getting the right to an additional 1 million acre-feet. The remaining 1.5 million acre-feet are apportioned to Mexico. The river flows were based on flows 1899 to 1920, an exceptionally wet period. (An acre-foot is the volume of water that would cover one acre to a depth of one foot.) But none of the states want to go back and draft new laws based on the realistic flows, except for maybe California, said Glenn Porzak, a water attorney based in Boulder who represents water entities and municipalities in both Summit and Eagle counties, as well as Vail Resorts.. “If you go back and say, ‘We made a mistake when we negotiated, we thought there was 17 million acre-feet.’ If you renegotiate, (Colorado’s) going to lose,” he said. “All water is political.” The 10-year rolling average flow at Lee Ferry cannot fall below 75 million acre-feet under the compact. That 10-year average over the last three years has been around 90 million acre-feet, according to U.S. Geological Survey data. In the early 2000s, the average was just more than 100 million acre-feet. Lake Powell in the Upper Basin and Lake Mead in the Lower Basin are the river system’s two main storage reservoirs, and both are approaching critically low levels. Inflows to Lake Powell over the last decade provide evidence of a sustained drought — in fact, according to climate data including the U.S. Drought Monitor and the National Climatic Data Center, the last 13 years have been the driest period in more than 1,000 years in the American West...more

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