Text Size

Site Search

Water Planning & Distribution

Irrigation and the Union Colony

Click the Fluent Water Facts below to learn more about Colorado's history.

Please update your Flash Player to view content.

Turning Colorado Green

Driving across Colorado today, we encounter lush green lawns, thriving cities, and acres of fertile fields. This is not Colorado’s natural landscape – much of it has been made possible through human ingenuity. Most green fields and lawns would not be possible without irrigation. The Union Colony, which established the town of Greeley, also laid the groundwork for Colorado’s modern irrigation and water law systems.

Water Brings Life to the Plains

In 1870, settlers arrived on the plains of northeastern Colorado with plans to found an agricultural town. The members of this group, known as the Union Colony, built shelter first, then turned to their greatest challenge. The success of the colony would depend on their ability to dig ditches that could carry water to their fields.

Irrigated agriculture in northeastern Colorado was very uncommon at the time. Most irrigated fields lay close to a river, but the Union Colony was miles away.

Building the canals was not easy. The first canal was intended to irrigate 5,000 acres, but it was only able to water 200 acres in June 1870. Construction of the next canal nearly caused the colony to go under. It was intended to irrigate 2,000 acres of planted seeds, but its supplies were insufficient for the hot summer of 1871 and most of the crops died. Nevertheless, the canal was eventually completed – 36 miles long and 32 feet wide, an engineering marvel. Within three years, the land was so productive that people stopped worrying about growing enough food to feed themselves, and instead worried how they would find markets for all their crops.

Imitating the Union Colony’s Success

Other towns learned from the Union Colony’s successes and engineered their own irrigation ditches. Greeley pioneers also helped develop irrigation systems for Fort Collins, Colorado Springs, Longmont, and Sterling.

Irrigated agriculture in Colorado is possible through extensive networks of canals and ditches, like those engineered by the Union Colony, as well as other water systems. Today, approximately 86% of Colorado’s water is used for agriculture. Learn more about agriculture in Headwaters magazine.

First in Time, First in Right?

In the dry summer of 1874, the Cache la Poudre River did not have enough water to supply both Fort Collins and Greeley. Fort Collins’ ditches were further upstream, but Greeley’s ditches had been built first. Greeley appealed for the water under the doctrine of prior appropriation – those who claimed the water first should have first priority in times of drought. Both sides recognized the need for some sort of regulation, and agreed to split the Cache la Poudre.

In 1878, construction of new canals prompted a statewide irrigation convention to codify Colorado’s water laws.   About 50 men representing 29 ditch companies and agricultural districts in the South Platte Valley met to discuss how to determine priorities, record water rights, and measure streams. Their work served as a template for legislation enacted by the Colorado General Assembly in 1879. These laws set nationwide precedent. They established Colorado’s prior appropriation doctrine for water law, known as “first in time, first in right.” They also established a court system to adjudicate water rights, and created water commissioners to divide streams according to court-decreed priorities. Colorado now had a legal framework to divide its water in times of need.

Water Origin Resources

The Citizen's Guide to Where your Water Comes From explains how weather patterns and aquifers supply the water we use. Learn more about the intricate distribution systems Coloradans have developed to deliver water to our farms and cities.  Flip through the online version or purchase a copy.

Citizen s Guide  4a40f4c93383c

The Citizen's Guide to Colorado's Transbasin Diversions highlights the history, costs and benefits of these controversial water projects, from both an historic and current point of view. Flip through the online version or purchase a copy.

Transbasin Diversions


1750 Humboldt Street, Suite 200
Denver, CO 80218