The history of the Colorado River mirrors the history of the American west. Competing water uses from the Colorado River system have defined Colorado history for over 100 years. The legal right to divert and use water in Colorado has been deliberated and defined from before the time of statehood in 1876. Article 16 of the Colorado constitution defines the water doctrine known as “prior appropriation”, which has stood the test of time as Colorado developed from a frontier western state to the modern era of the late 20th century. Since 1876, the constitution and subsequent water court rulings have governed the use, diversion and storage of water in Colorado. “Prior appropriation shall give the better right as between those using the water for the same purpose….” is a Colorado constitutional excerpt that is the basis for the first in use, first in right doctrine of water appropriation. This Colorado water doctrine has become one of the legal foundations upon which water is governed, managed and distributed in Colorado.

The Colorado Water Conservation Board (CWCB) oversees water and related issues in the State of Colorado. As part of the Department of Natural Resources, the CWCB is involved in many water management and policy issues in Colorado. The Colorado Division of Water Resources provides specific services to citizens of the state including administration of laws in accordance with court decrees and state legislation.

The State Engineer’s office in Colorado has maintained meticulous records on water usage, diversions and streamflows for many years. Presently the state is divided into 7 water divisions, with 80 districts. Two hundred professional staff members work together to administer Colorado’s water according to the Colorado doctrine of prior appropriation, state law, water court decrees and interstate compacts.

Colorado has the enviable position in the west as being a water producing state that has numerous mountain ranges from which the rivers are supplied. While the water provided by annual Colorado streamflows is more than ample, the seasonal nature of streamflows is not consistent with the demand by Colorado citizens for domestic, agriculture and industry uses. Nearly 2/3 of the annual water flow (measured in acre feet of water) occurs during the late spring/early summer runoff. During the winter months of December, January and February only 3% of annual flows occur.

Presently, Colorado reservoirs store the spring runoff from mountain snowpack for use in the late summer and low flow winter months. This “reserved” water is stored for use throughout the year by downstream users. In addition, water storage units along the Colorado River system provide flood control, recreational sports, excellent fishing and hydro-electric power.

As a water producing and exporting state, Colorado water leaving the state on an annual basis exceeds 10 million acre feet. The main stem of the Colorado River west of Grand Junction provides nearly 5 million acre feet of that amount for downstream users. The Colorado River Compact is the ruling document that was established after long negotiations between the seven states along the Colorado River in 1922. Although the Colorado Compact formed the basis for the “Law of the River”, much debate and deliberation was to follow the historic 1922 treaty. The State of Wyoming consistently challenged Colorado’s right to divert headwaters streamflow from the west to east slope of Colorado. After the U.S. Supreme Court ruled that the waters of the Colorado River would be governed according to the Doctrine of Prior Appropriation, the Upper Basin states (Utah, New Mexico, Wyoming and Colorado) became concerned that the Lower Basin states would be at an unfair advantage due to their more rapid development of water resources. As a result of complex negotiations between the states in a forum called the Colorado River Commission, the elements of the famous Colorado River Compact were forged between the 7 states along the Colorado River system.

In 1902, the US Bureau of Reclamation (USBR) was created as an agency of the federal government. Over the past 90 years the USBR has been coordinating the planning, construction and implementation of numerous water diversion and storage projects in the western United States. Irrigation projects throughout the west are based on contracts between the water users and the USBR. Hydro-electric power revenues from Colorado River Storage Projects are used to offset some of the costs of irrigation projects and repayment contracts. Usually, water for domestic use is charged a higher rate than irrigation water in USBR repayment contracts. The USBR manages existing water reservoirs in the Colorado River System that were constructed with federal financing. Colorado River System reservoirs that have federal financial obligations are in the process of being repaid to the U.S. government by water users and hydroelectric revenues. For example, Vallecito Lake north of Bayfield, Colorado, was completed in the early 1940’s. In the early 1980’s, the Pine River Irrigation District paid off its U.S. government obligations and operates Vallecito Lake debt free.

In 1944, a treaty was signed with Mexico providing our neighbor to the south with 1.5 million acre feet annually from the Colorado River system. In1948, the Upper Basin States agreed to a percentage appropriation of the waters of the Colorado River System. Colorado’s share of the 7.5 million acre Upper Basin allotment was set at 51.75%. Subsequent negotiations among the Seven Basin states and court decrees have quantified Colorado’s share of the Colorado River system, which is estimated to be approximately 3.1 million acre feet of water per year.

As in the past, the Colorado River system continues to provide water to millions of residents of the Colorado Basin and generates economic benefits in direct and indirect ways. Indian water rights, endangered species, water quality, interstate conflicts and environmental legislation are impacting the water users and states along the Colorado River system. Present and future generations will continue to wrestle with the issues of the Colorado River. Over the past 100 years, the history of water in Colorado has helped shape the “Law of the River” throughout the Basin and our state. While the conservation, use and storage of water will be a source of debate among users and the states, water continues to be Colorado’s most precious resource. How we manage, conserve, store and distribute water will remain one of Colorado’s most pressing policy challenges.