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Water Law & Supply


Water is essential to life. It is used to generate power, irrigate crops, for drinking water, and to support various ecosystems. Colorado has an arid climate, with most precipitation falling as snow during the winter far away from the population centers in the Front Range. Boulder receives approximately 18 inches of precipitation a year. Snowmelt during the spring creates a surge of water that flows down through the rivers and creeks. Often during the remainder of the year the majority of the rivers and streams are too low to provide for the multiple users. To overcome this seasonal scenario, water is dammed and stored. Water is our most managed resource. 

As a result of the scarcity of water in the West, complex water distribution systems, water laws, and water agencies have been developed to manage this precious resource. 

Colorado Water Law 

Settlers migrating west quickly realized that western land and water resources were much different than those in the humid eastern region they had come from. Due to the aridity of the West, miners had to develop a new system for water allocation and use. The water allocation system used in the east, riparian water rights which tied water to adjoining lands, would not work in a region where much of the usable land was not adjacent to the  rivers and streams. The solution to western water allocation was found in the doctrine of prior appropriation, "first in time, first in right", which was born in the hills of California where miners battled it out for unlimited use of water for their mining operations. The doctrine of prior appropriation was later adopted by farmers who started diverting rivers for irrigated farming.  The historic "Left Hand vs. Coffin" decision of 1881, in which the Colorado Court ruled in favor of a farmer who diverted water from the South St. Vrain into James and Left Hand Creek, set the stage for what has become known as the "prior appropriation doctrine" in Colorado. (Click here for more on the history of irrigation in the Boulder Valley from local author Anne Dyni, or visit BASIN History.)

The prior appropriation doctrine also controls the distribution of water in Colorado. Those water users that were here first have "senior" rights and get first call on water. However, they can only use as much as they have used in the past. Use is defined as "beneficial use," which can be very loosely interpreted. "Beneficial use" in the Colorado Constitution gave top priority to domestic use, second priority to agricultural use, and third to manufacturing use. 

The first time local water rights were adjudicated, or recognized by the Boulder County District Court was in 1882. Ninety-eight ditch companies were accorded a priority right and irrigation ditches were constructed to bring water from South Boulder Creek, the St. Vrain River, Boulder Creek, and the Big Thompson River to irrigate the area's first crops of wheat and turnips. 

Today, many streams are over allocated, that is that every drop of water is spoken for by a user. Sometimes there is not enough water left for the fish and other organisms that use the stream. 

Because water has many users it is important to understand that managing water involves tradeoffs. Extensive negotiation along legal, scientific, and social lines occurs when determining how to distribute water. Clean drinking water might have to be balanced against leaving sufficient water in the stream for aquatic life, agriculture might have to be balanced against hydroelectric generation. 

Key Words 

Acre-foot: the amount of water that would cover one acre at a depth of one 
foot (325,900 gallons). It is enough water to meet the inside, lawn 
watering, and industrial needs of 4-5 urban people for one year. 

Doctrine of Prior Appropriation: "first in time, first in right" 

Water rights: legally established right to appropriate water from a given 

In-stream flow: water rights that are used to insure enough water remains in 
the stream to support aquatic life.

"Pass the Jug" Activity 

There are a number of ways to play "Pass the Jug". If you are in a classroom situation your teacher may have you apply local water law and history to the activity. A simple way to play, however, is to take a group of people, each with an empty glass. Have each stand in a row and pass a jug or bottle of water around, everyone taking as much as they want. The people at the beginning of the row are like those with senior water rights ("first in time, first in right"). Those towards the end of the row are not such a high priority. Will there be enough water for them, especially if it is a hot day and there is a small jug?

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Last Page Update - Tuesday December 27, 2005