In Colorado, citizens need a legal permission to remove water from a river for agricultural, municipal, recreational, or industrial use. Removing water from a river or aquifer “by means of a water structure such as a ditch, pipeline, boat chute, whitewater course, reservoir, or well,” is called a diversion.[1. Hobbs, Greg, Citizen’s Guide to Colorado Water Law (Denver: Colorado Foundation for Water Education, 2009), 6.] A court-approved right to divert water from a particular place for a specific purpose is called a decree, and the process by which a court approves a diversion decree is called adjudication.[2. Hobbs, Citizen’s Guide, 13-14; R. Waskom, E. Marx, D. Wolfe, and G. Wallace, “Irrigation Ditches and Their Operation,” Colorado State University Extension, http://www.ext.colostate.edu/pubs/natres/06701.html. ]

In the 1860s, settlers, such as John Coy and Alfred Edwards, dug canals and diverted water from the Cache la Poudre River at will to irrigate farms and provide power to flour mills. When Colorado became a state in 1876, it codified the Prior Appropriation System to govern water diversions from rivers and streams, recognizing that the demand for water exceeded availability. Next, the Colorado General Assembly passed the Adjudication Acts of 1879 and 1881, giving the state’s courts the power to oversee the administration of river priorities and requiring that those who wanted to confirm a water right, “…file a claim in court to establish the validity of their right.”[3. P. Andrew Jones and Tom Cech, Colorado Water Law for Non-Lawyers (Boulder: University Press of Colorado, 2009), 66; Justice Gregory J. Hobbs, Jr., “Colorado’s 1969 Adjudication and Administration Act: Settling In,” University of Denver Water Law Review, 1, no. 3 (1999): 5-7.] Decrees sanctioned holders’ permission to take a specific amount of water from an exact point on the river and assigned the right a diversion priority number. The courts confirmed the earliest diversion rights for the Cache la Poudre through legal decree in 1882.[4. Colorado courts refer to the confirmation of rights as “adjudication.” For the earliest rights, see Victor Elliott, Decree in the Matter of Priorities of Water Rights in Water District No. 3, Entered by the Hon. Victor A. Elliott, Judge of the Second Judicial District, April 11, 1882 (Fort Collins: Evening Courier Printing House, 1882).] Today, the Cache la Poudre River is over-appropriated (greater demand than availability of water), and city governments, businesses, and private citizens are rarely allowed to create new diversions because little if any water is available. In most cases, those who need water from the river purchase a decreed, historic right from a current water right owner rather than create a new diversion.