A dry and thirsty land
Dropping water levels along the Colorado River highlight the West’s worsening drought
For more than six decades, the water district in Colorado’s Mesa County has depended on runoff from the 11,000-foot Grand Mesa to fill up reservoirs and meet the western region’s water needs. This year, officials with the Ute Water Conservancy District think they might need more.
Drought in the American West has left the ground so desiccated that county water managers say snowmelt this past spring soaked into the ground rather than running into creeks that feed the reservoirs. In June, officials with Ute Water for the first time ever began exercising their legal right to pull water from the Colorado River to keep reservoirs near Grand Junction, Colo., filled.
Like many in the region, Mesa County officials are bracing for the consequences of a multi-year drought exceptional even for the dry Mountain West. “2018 was a pretty bad year, ’19 was decent, ’20 was pretty bad and now we’re in ’21, where runoff just wasn’t as generous as we hoped it would have been,” Ute Water External Affairs Manager Andrea Lopez said. “Over time it just gets worse and worse.”
As the drought reduces some Western reservoirs to record lows, potential water use conflicts heat up between states. And as more farmers and water utilities draw on the already-parched Colorado River as a lifeline, scientists are beginning to question exactly how much life the river can sustain in one of the nation’s most arid regions.
The University of Nebraska’s Drought Monitor uses a four-part scale to classify drought. According to a report released July 1, nearly everywhere west of the Continental Divide in the Rocky Mountains is in some stage of drought. And 58 percent of Arizona, 65 percent of Utah, 41 percent of Nevada, and 33 percent of California are suffering from exceptional drought—the monitor’s most severe rating.
From its headwaters near Rocky Mountain National Park, the Colorado River knifes through the mountains of Colorado and Utah before demarcating the boundary between Arizona, Nevada, and California. Today, much of the 1,450-mile-long river and its watershed encompasses the lands under exceptional drought conditions.
Nowhere illustrates the problem more vividly than Lake Mead, the giant reservoir on the river created by the Hoover Dam. On July 4, water levels at Lake Mead reached a new historic low, more than 160 feet below the height at which officials consider the lake full. At just 35 percent of its capacity, the lake shows other physical signs of drought. The slow and steady declining water levels have left a bathtub ring of white sediment mineralized on rockface that once stood underwater. Water levels are no better on the Upper Colorado. Utah’s Lake Powell, a reservoir second only to Lake Mead in terms of water storage capacity, stands just 34 percent full.
“This [rapid decline] scares me,” University of New Mexico Director of Water Resources John Fleck told CNN. “It’s dropping so fast that it may be overreaching our ability to cope with the problems. I did not anticipate the bottom to drop this quickly.”
Lower water levels translate to lower electricity production at hydroelectric plants along the river. Electricity production at the Hoover Dam dropped by 25 percent by June and could fall further even as record-breaking temperatures across the West prompt increasing demand for power, according to the Bureau of Reclamation, the federal agency that oversees water resource management in the region.
Scientists blame at least some of the decreasing flow of the Colorado River on decadeslong rising temperatures across the region. Earlier this year, Desert Research Institute hydrologist Rosemary Carroll published research examining the impact of warmer temperatures on the volume of water moving through the Colorado’s basin. During cooler years, Carroll said, soil in the area retains more moisture, allowing monsoon rains and annual snowmelt to flow into rivers and streams. Not so during periods with high temperatures.
“You can think of the soil zone as a sponge that needs to fill up before it can allow water to move through it,” Carroll said. “So, if it’s already depleted because you had low snowpack, the monsoon then has to fill it back up, and that decreases the amount of water you actually get in the river.”
That’s bad news for the 30 million people who depend upon the Colorado River and its tributaries for water. And it could be worse still for farmers and ranchers who collectively irrigate 4 million acres of semi-arid land for agriculture in the region. Sorting out claims to a diminishing water supply in the river’s basin may even eventually lead to a seven-state lawsuit as states dependent on Lake Mead sue upper basin states to release more water from Lake Powell.
But before that happens, the Bureau of Reclamation will likely declare the region’s first water shortage by August after releasing new projections for Lake Mead and Lake Powell. The declaration of an emergency on the Colorado could lead to Arizona losing 18 percent of its share of the Colorado’s waters.
“It should represent an earthquake in people's sense of urgency, on all fronts,” Felicia Marcus, a fellow at Stanford University’s Water in the West program, told USA Today. “We need to accelerate everything we can to use less water.”
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