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“Water Horse has investigated and answered some of the commonly raised concerns regarding impacts of a new water withdrawal from the Colorado River system”


Isn’t the Colorado River system water over-subscribed and there is no water available water for Water Horse?

Based upon an analysis of historical flows, the Bureau of Reclamation has determined that the Upper Basin is entitled to slightly over 6 million acre-feet of water each year. Colorado’s apportionment of the amount available is 51.75%, which it is currently not taking.

The Colorado Water Conservation Board (CWCB) has assessed the amount of water available to Colorado under its Compact share. The CWCB study determined that even after development between now and 2030, Colorado will have an undeveloped share of 302,000 – 654,000 acre-feet available.

The Bureau of Reclamation has modeled the amount of water available by assuming that the Upper Basin states would develop new projects they have currently identified, that flows below Flaming Gorge Reservoir would be maintained at the levels established by a recent Record of Decision as needed to protect endangered fish, and that reservoir water levels would be maintained as needed to generate electricity.

The Bureau concluded that there will be at least 165,000 acre-feet available for the Green River project each year for the next 40 years.

Do Colorado water users have the right to divert water from the Colorado River System in Utah or Wyoming?

They clearly do, yes.

A unique feature of the Water Horse Project is that Colorado’s water will be diverted with a head gate in Utah or Wyoming for use in Colorado. Article IX of the Upper Basin Compact anticipated this situation and directs the state where the diversion is located to apply its law, except that storage and releases shall be permitted for the benefit of Colorado.

There is precedent for a water user in one Colorado River Compact state diverting water from another Colorado River Compact state.  A current example is the proposed Lake Powell project taking water out of Lake Powell in Arizona for use in Utah.

Under the Upper Colorado River Compact, water diverted in one state and put to beneficial use in another is charged against the Compact allocation of the state of use.

Wouldn’t diverting these waters for Water Horse put Colorado at risk of a call under the Colorado River Compact?

There are those who suggest that Colorado should not develop its remaining Colorado River Compact entitlement because further development might precipitate a Compact call. Other states, however, are proceeding. If Colorado hesitates, it subsidizes development by its sister states, while depriving itself of needed water. In most if not all years, water is available for Colorado’s use. It would be far better to develop Colorado’s entitlement and then to manage the resource in dry years so as to avoid a Compact call than to forego the water.


Under the Colorado River Compact, there will be no “call” unless the Upper Basin fails to deliver 75 million acre-feet at Lee Ferry during any consecutive 10-year period. Since the Compact was adopted, this never has happened. The ability to adjust over a 10-year period, substantial under-use of Wyoming’s Compact share, the role of Lake Powell, and the agreement among the Upper and Lower Basin states to coordinate the operation of Lakes Powell and Mead so as to avoid curtailment of uses in the Upper Basin all mitigate against there being a Compact “call.”

Should there be an under delivery to the Lower Basin over a 10-year period, the Upper Basin Compact specifies how the shortfall shall be met. If an Upper Basin state has taken more than its share of water, that state first must replace its overdraft. New Mexico’s Compact apportionment is almost fully used now; Utah will increase its use substantially with the Lake Powell pipeline. Therefore, it is reasonable to expect that curtailment would operate first against water rights in New Mexico and Utah. However, should further curtailment be necessary, each state will bear part of the obligation, based upon its water use from the Colorado River system during the preceding year. This situation would require Colorado to determine which of its water rights, including the Water Horse Project, must be curtailed.

Won’t the Water Horse Project hurt agricultural and other Western Slope water users in Colorado?

No, it will not.

Unlike other projects, the Water Horse Project draws upon the Green River and not upon the other Colorado streams – e.g., the Blue, Colorado, Fraser, Gunnison, Yampa – that now supply consumptive and non- consumptive uses in western Colorado.

The Water Horse Project will protect the western slope by providing new water to the eastern slope, relieving pressure for further development off of western slope streams.

The Water Horse Project will relieve pressure on overdrawn aquifers in eastern Colorado, will protect agricultural water use by relieving pressure on municipalities to take water out of agricultural use, and will protect existing wells by providing a new source of affordable augmentation water.

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