An initial OOOps in “managing” Colorado River water occurred in 1922 when the seven-state compact split the river’s geography into two equal units: Upper Basin and Lower Basin. The OOOps involved using water data from 1905 to 1922 as the basis for estimating water allocations.
The early 1900s, as later determined by analyzing tree stump rings, were a high water mark for the river. The 1922 river volume estimates hit 16.4 million acre feet/year. One acre foot, or about a football field flooded with one foot of water, serves one to two families in a year.
More recent work sets the river’s volume about 3 to 4 million acre feet less than in 1922, and it’s been dropping at a fast rate since drought hit the west over the last 20 years. To make this difference vivid, the 2021 inflow into Lake Powell will be the second lowest ever recorded. It’s expected to be 31 percent of a 30-year average.
The drought is now so significant that the U.S. Bureau of Reclamation has recently issued a Tier 1 warning to the compact states. The warning comes from the impact on Lake Mead reservoir of less water moving through the river from the upper states to the lower states.
The Colorado River Compact allots 7.5 million acre feet to the upper basin and 7.5 million to the lower basin. Since the upper basin has not consistently used all its allotment, California gobbles up the surplus water. It goes to San Diego, Los Angeles, and the Imperial Valley, a desert irrigated almost exclusively by the Colorado River. California has senior water rights on the Colorado River which allows it to take one-third of the total allotment.
Arizona has junior water rights. It accepted this position when the state’s politicians in the 1960s convinced the US Congress to build the Central Arizona Project (CAP) with its intricate 336 mile aqueduct and diversion canal system to irrigate another desert. The CAP may end up being another Colorado River management OOOps.
Arizona farmers grow mostly cotton and alfalfa. Both crops are among the most water intensive to raise. Arizona’s alfalfa is sold for cattle and dairy feed to Asia. The demand for high quality cotton out of Arizona has gone down due to COVID and trade wars just as it reached some bumper crop years. Arizona farmers will initially fallow some of their fields, but continuing drought will no doubt pressure crop viability and take land out of cultivation.
Colorado’s water position with the Colorado River is better than Arizona’s by far. Our state gets 51 percent of the river’s upper basin allocation. Amounts will obviously vary by year depending on rain and snow fall. The upper basin in 2020 used almost 5 million acre feet. The lower basin used its full allotment at 7.5 million acre feet according to the University of Arizona.
Needless to say, if the upper basin draws on its full allotment, given the reduced status of Lake Mead, lower states will be in a world of hurt. Colorado has a Water Plan that resides with the Colorado Water Conservation Board in the Department of Natural Resources. It was developed using a stakeholder process in 2015. It has five economic scenarios identifying the water gaps the state may experience in the near future. The scenarios run from “business as usual,” to “adaptive and cooperative growth,” to “hot economy.”
The scenarios show the interaction of human decisions for business, agriculture, and population growth on water usage. Added to the scenarios are the state’s water values: clean water and sustainable river basins as well as enough water for fish and wildlife to thrive, for four-season recreation, and for municipalities to remain vibrant. Summer recreation is currently hurt by low rivers and warm water temperatures that threaten fish populations.
2022 will be a big year for Colorado River water management across the western states. It’s the 100 year anniversary of the Colorado River Compact. Renegotiations begin on water flow and distribution. Reduced fish populations are the canaries. It’s time to listen to what nature is telling us. Nature’s message is not what’s been in place for a century: “water runs uphill to money.”