“The Colorado River has been over allocated from the beginning.”

By Linn Smith
September 11, 2018—-The Law of the River is a Colorado River Compact formed in 1922. It’s an agreement between 7 states in the Colorado River Basin. The upper division is Colorado, New Mexico, Utah, and Wyoming and the Lower Basin states are Arizona, Nevada and California. All management of the river is called the “Law of the River.”

High Precipitation in 1922

Tree rings have been studied from 1922 which show that the flow of the Colorado River during the original signing was at an all time high. The 3 years around the establishment of water rights were very wet years with high precipitation. Therein lies part of the problem of over allotment of the Colorado River. The river was at peak flow in 1922, allowing more than enough water for all.

The Law of the River

The Law of the River declares the upper basin states should not deplete the flow of the river below 7,500,00 acre ft. (An acre foot would be equivalent to an acre of land being flooded with 1 foot depth of water) during any 10 consecutive years. But rainfall was at an all time high when the Law of the River pact was signed. With the rainfall patterns of 1922, this would have allowed for a roughly equal flow between the upper and lower basins and enabled widespread irrigation of the arid southwest to grow fruits, and vegetables, as it continually had done with very few problems in the 20th century.

The Colorado River and Population Growth

Today the population of states along the Colorado River has increased, requiring greater demand on the river, which has decreased, causing many legal water disputes. Over 40 million people, 18 million in lower basin states, depend on the Colorado river for water and the power it creates. Hoover Dam generates, on average, about 4 billion kilowatt-hours of hydroelectric power each year for use in Nevada, Arizona, and California – enough to serve 1.3 million people! Without the Colorado River and the power it generates, millions of people would have a greater dependency on fossil fuels.

Since the development of the river compact, California has been using the surplus water that other states haven’t used in the lower basin. But with population growth both Arizona and Nevada are claiming their water allotments, forcing California to resort to greater water conservation policies. Growth in the other lower basin states will not allow the surplus flow to California.
(see, https://planetearth5.com/2018/08/26/irrigation-and-water-depletion-in-the-southwest-united-states/)

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The Drought in the Southwest

The Colorado River has been over allocated from the beginning and the flows were overestimated. The estimation was 17 million acre ft a year, but the flow has been much less for most of the years since the signing of the compact. Forecasts state that the Colorado river will only carry about 43% of the allotted water into Lake Powell in the future, as the drought in the Southwest has been taking place for the past 18 years, which some say is a permanent shift at least in part due to global warming.

Conserving the Colorado River

Kim Mitchell of Western Resource Advocates states, “People in the seven S.W. states must learn to live with less water. Unless we take decisive proactive steps now, farmers, cities, business and environment all will lose water….they must understand that more water is being pulled out of the river than is being replaced. The problem is compounded by a long-term drought and climate change.” U.S. Bureau of Reclamation, Aug 15, 2018, anticipates declaration shortage in Sept 2019 that would trigger reduced water releases from federal reservoirs in the lower basin states.

Recently the Upper Basin states accused CAP, Central Arizona Project, of manipulating its share of water to keep Lake Mead low enough that the upper basin is required to send extra water, but high enough to avoid mandatory cutbacks in lower basin consumption. The water wars will continue!

Adoption of additional water conservation measures now is the best approach to protect the Colorado River as continued long-term solutions are developed.

Depletion of the Colorado River

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