The Winter 2021-2022 Newsletter is hot off the presses from the Upper #GunnisonRiver Water Conservancy District #GunnisonRiver #ColoradoRiver #COriver #aridification

Click here to read the newsletter. Here’s an excerpt:

Can the Law of the Colorado River Adapt to an Increasingly Drier Hydrology?

A Two-Part Article by John McClow, UGRWCD Legal Counsel

The Gunnison River is a major tributary of the Colorado River. The Colorado River Basin has suffered from drought conditions throughout the 21st Century. The two major reservoirs in the Colorado River System – Lake Mead and Lake Powell – are at historic and dangerously low storage levels. Locally, Blue Mesa Reservoir is a stark illustration of the effects of the current dry conditions. Scientists are warning that “drought” is a term that no longer applies because it implies a temporary condition from which the Basin will recover. A more accurate term is “aridification” because the conditions we have experienced during the past 20 years will continue – or worsen – for the foreseeable future, as hotter and drier conditions make matters worse. Recently published projections indicate that river flows may decline 20 percent by midcentury and 35 percent by the end of this century. There is debate about the causes of the decline, but little disagreement that it will continue to happen. Can the Law of the Colorado River – numerous compacts, federal laws, court decisions and decrees, contracts, and regulatory guidelines – founded on a 100-year-old Compact – adapt sufficiently to meet the challenge of aridification?

Brad Udall: Here’s the latest version of my 4-Panel plot thru Water Year (Oct-Sep) of 2021 of the Colorado River big reservoirs, natural flows, precipitation, and temperature. Data (PRISM) goes back or 1906 (or 1935 for reservoirs.) This updates previous work with
@GreatLakesPeck.

PART 1: A Brief Summary of the Law of the Colorado River

The foundation of the Law of the River is the Colorado River Compact, signed by the seven Colorado River Basin States and the United States in 1922. The Compact is a contract among the signatories ratified by the seven states and Congress and became state and federal law. The Compact divides the Colorado River Basin into an Upper Basin (Colorado, Wyoming, Utah, New Mexico) and a Lower Basin (Nevada, Arizona, California). It apportions to the Upper and Lower Basins the beneficial use of 7.5 million acre-feet of Colorado River water per year. It requires that the states of the Upper Basin will not cause the flow of the river to be depleted below an aggregate of 75 million acre-feet for any period of ten consecutive years – measured at Lee Ferry, the dividing point between the Basins. It also describes how the Basins will share water delivery to Mexico. The Compact contains no reference to “curtailment” or a “Compact call.”

In the 1928 Boulder Canyon Project Act, Congress authorized construction of Hoover Dam (Lake Mead) and directed that the 7.5 million acre-feet allotted to the Lower Basin under the 1922 Compact be apportioned: California, 4.4 million acre-feet; Arizona, 2.8 million acre-feet; Nevada, 300 thousand acre-feet.

The United States signed a treaty with Mexico in 1944 that guarantees an annual delivery of 1.5 million acre-feet of Colorado River water to Mexico. In 1948, the Upper Basin States signed the Upper Colorado River Basin Compact, which apportions the 7.5 million acre-feet allotted under the 1922 Compact: Colorado, 51.75 percent: Utah, 23 percent; Wyoming, 14 percent; New Mexico, 11.25 percent. The 1948 Compact created the Upper Colorado River Commission (UCRC), consisting of a Commissioner appointed by the Governor of each state and a federal Commissioner appointed by the President of the United States. It also provides that if curtailment of use in the Upper Basin is necessary to maintain the flow at Lee Ferry required by the 1922 Compact, the UCRC will determine each state’s extent and timing of curtailment. It is important to note that neither the 1922 Compact nor the 1948 Compact affect water right administration within the states. In Colorado, that authority remains vested in the State Engineer.

Graphic via Holly McClelland/High Country News.

In 1956, Congress passed the Colorado River Storage Project Act. The Act authorized construction of the reservoirs, dams and power plants of the initial units of the Project: Wayne N. Aspinall (originally the Curecanti Unit), Flaming Gorge, Navajo (reservoir and dam only), and Glen Canyon (Lake Powell), along with numerous participating projects, “making it possible for the States of the Upper Basin to utilize, consistently with the provisions of the Colorado River Compact, the apportionments made to and among them in the Colorado River Compact and the Upper Colorado River Basin Compact, respectively.” The CRSP power plants are an important source of hydropower in the Western United States, and the revenue from the sale of that hydropower supports operation of the Project and important salinity control and endangered fish recovery programs.

The Colorado River Basin Project Act, passed by Congress in 1968, authorized construction of the Central Arizona Project, which can divert 1.5 million acre-feet from the Colorado River to central and southern Arizona. Construction of the CAP allowed Arizona to develop its full apportionment of Colorado River water. The Act confirms California’s senior priority to 4.4 million acre-feet of Colorado River water, meaning that Arizona and Nevada must bear any shortage in the Lower Basin.

Next Issue: PART 2: Adapting the Law of the River for a Dry Hydrology

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