Known collectively as “The Colorado Doctrine,” the state’s water laws arose primarily from the practice of farmers diverting water from streams through ditches onto irrigable land to grow food for homesteading families, miners, and growing towns.
In 1861 the Colorado Territorial Legislature adopted a water act providing that anyone needing irrigation water could remove it from a stream for use on agricultural lands, whether or not those lands bordered a stream. This law also allowed people who wanted to use water but lived away from the stream to build and operate the head gates and ditches necessary to carry the water from the stream and the location of use across land they did not own. The Territorial Supreme Court upheld these laws in an 1872 decision, which it based on the “imperative necessity” of water use for settlement in arid parts of the public domain.
The water provisions of the state’s 1876 Constitution ratified Colorado’s complete departure from the riparian common law of England and eastern states, which enjoyed abundant precipitation with no need for consumptive use irrigation. Under riparian law, only owners of property bordering the stream may divert water. A diverter must return the water to the stream essentially undiminished in quantity and unaffected in quality, because riparian land owners up and down the stream enjoy an equal right to the stream’s flow.
The framers of the Colorado Constitution rejected riparian law as entirely unsuitable, because irrigation is necessary to grow crops in this region, where annual precipitation averages less than twenty inches. They also shared the anticorporate, antispeculation views of the mid-nineteenth-century agrarian reform movement, which favored small farmers over moneyed interests. They feared that unless riparian law were disavowed, foreign financial interests would buy up the land along the streams and create a water monopoly that would deprive small farmers of an affordable water supply.
As a result, the Colorado Constitution stipulated that the doctrine of prior appropriation shall govern the apportionment of water rights. That is, whoever first puts water from a given source to use will enjoy a right to the amount of that initial use. Subsequent users may appropriate water from the same source, but never to the extent that it diminishes the amount needed by previous users. Prior appropriation is sometimes summarized as “first in time, first in right.”
Thus, Colorado’s constitution, General Assembly statutes, and Colorado Supreme Court case law decisions entirely reject riparian law in favor of these principles: (1) all surface and groundwater within Colorado is owned by the public and is dedicated to the use of the people through water rights established as prescribed by laws of Colorado and the United States; (2) court decrees and groundwater permits enforced by state water officials define the right of water use for a wide variety of agricultural, municipal, commercial, recreational, and nonconsumptive flow purposes; (3) water users may obtain a right of way across the lands of others for the construction and operation of needed diversion, conveyance, and storage structures by paying just compensation (a reasonable amount paid in compensation for property losses incurred by the owner because of the right of way); and (4) the streams and aquifers (permeable underground geological formations that hold water or allow it to pass through) can be used to transport and store water without interference by riparian landowners.
In creating public water ownership and also providing for public and water use rights to be established separately from land rights, Colorado relied on a series of US Congress public domain acts, including the 1866 Mining Act, which confirmed the right of the states and territories to adopt their own water laws and create water use rights in unappropriated water of the public domain.
State Administration and Classifications
Colorado has chosen to allocate and administer water according to four classifications: (1) waters of the natural stream, which includes surface water and groundwater that are capable of passing to a surface stream; (2) designated groundwater of the eastern high plains; (3) nontributary deep water (that is, water that does not pass to or from a stream or other surface source) located outside of designated groundwater basins; and (4) Denver Basin groundwater of the Dawson, Denver, Arapahoe, and Laramie-Fox Hills aquifers. All of these types of water are owned by the public, but only waters of the natural stream are subject to allocation by the doctrine of prior appropriation under Article XVI, Sections 5 and 6, of the Colorado Constitution. The other three types of groundwater are subject to allocation and administration according to statutes of the Colorado General Assembly.
Federal Water Rights
The 1908 US Supreme Court case Winters v. United States established the doctrine of federal reserved water rights. This meant that federal public reservations, such as an Indian reservation or a national park, include the necessary water rights to sustain the purpose of the reservation. These kinds of rights exist in Colorado for the Ute Mountain and Southern Ute Tribes and national parks and monuments. Although creations of the state government, Colorado’s seven water courts—established in major watersheds of the state—issue decrees for both federal and state water rights because Congress allows state courts to adjudicate claims involving federal water rights. Colorado is a leader in integrating state and federal water rights into a unitary system of priority enforcement, first in time, first in right, administered by the state engineer, seven division engineers, and local water commissioners.
Interstate Compacts and Supreme Court Decrees
US law requires the sharing of interstate stream water between upstream and downstream states. As a result, the state’s water officials must also enforce compliance with nine interstate compacts and two US Supreme Court equitable apportionment decrees that limit the amount of water Colorado can consume from its streams and connected aquifers. Because water deliveries must be made to other states downstream, Colorado can consume approximately only one-third of the annual amount of water produced by Colorado snow and rain, even though the South Platte, Republican, Arkansas, Rio Grande, and Colorado Rivers originate within the state.