Wyoming State Water Plan, Wyoming Water Development Office
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Green River Basin Advisory Group
Meeting Record
Sweetwater County Library, Green River WY
October 10, 2000


Facilitator Joe Lord welcomed the group and the meeting was opened at 5:00 p.m. The overall meeting agenda was reviewed, followed by an introduction of all attendees. A sign-in sheet was passed around to record attendance.

Planning Team Issues

Jon Wade provided a rundown of the upcoming meeting schedule:

November 14, 2000Farson 1:00TBA
December 12, 2000Rock Springs 1:00TBA
January 9, 2001 Rock Springs 1:00TBA
March 20, 2001 Pinedale 10:00 TBA

Discussion was held on the meeting schedule that will occur after the consultant report is complete. The January meeting will be the final consultant presentation of the plan, and after that a relaxed schedule is suggested to deal with topics as they come up. Originally, the WWDC put forth a schedule of meetings in March, July and November of 2001. Some BAG attendees indicated that a more pure quarterly schedule be adopted, one that more closely resembles the old Colorado River Coordinating Council meetings, with the State Engineer in attendance to brief the group on the status of current political and institutional issues. This mechanism seemed favorable to most of the group, but the scheduling of meetings beyond March was left as a future decision.

Jon Wade then updated the group on the progress of the NE WY basin plans. Both NE Wyoming BAGs are grappling with issues identification at this time.

Consultant Update

Pat Tyrrell of States West was introduced, and gave a presentation that was a continuation of the previous meeting's discussion of draft plan results. Pat's presentation emphasized projected agricultural uses and criteria for ranking future water use opportunities.

To begin Mr. Tyrrell presented current municipal, industrial, agricultural and environmental uses. In a discussion of evaporation losses, the concept of "main stem evaporation" was explored in some depth. Main stem evaporation is Wyoming's share of evaporative losses from main stem reservoirs including Flaming Gorge, Lake Powell, Blue Mesa and Morrow Point Reservoirs. By Compact, Wyoming will bear 14 percent of the total evaporation from these reservoirs at full development (full use of allowed depletions). Until full development, main stem evaporation is not formally attached to Wyoming's depletion, but some consideration of its effect must be made because of the size. (Editors post-meeting note: at 14 percent, Wyoming's current share of main stem evaporation is about 88,500 AF. At full development, Wyoming's share would be 72,800 AF. These quantities amount to 11 and 9 percent of Wyoming's total apportionment of 833,000 AF.)

The presentation then moved into a discussion of future agricultural uses. This is the most difficult area to project because the true "demand" for agricultural water is strongly a function of the price irrigators would have to pay for it. This is a wrinkle not typically faced by industrial or municipal users who are more able to pay and for whom the cost of water development is typically less of a factor. An additional factor in future agricultural demand is the existing condition of many irrigators being short in late summer for lands already under irrigation. In this sense, future irrigation water should be developed first to make existing operations whole before new acres can be considered for production. Even in normal years, most irrigators receive less than full supply in August and September, establishing a need for late season water for most operators in tributary basins without existing storage.

Among all the tributary basins in the Green River Basin of Wyoming, those in the northwest, from approximately Fontenelle Creek on the south to Horse and Beaver Creeks in the north, suffer most from lack of storage. This part of the basin also contains the largest assemblage of currently irrigated lands. Of the roughly 300,000 irrigated acres in the basin, over 130,000 are in this region, about 40 percent of the total. Based upon work done by the Bureau of Reclamation (in the Savery-Pot Hook Definite Plan Report) and a study by ARIX in 1983 on reservoir sites in the northwest tributaries, August and September shortages (indeed, normal years often also see shortages in July for many irrigators) are the norm. This late season lack of water is estimated to translate into a 25 to 30 percent shortage based on full CIR (consumptive irrigation requirement). For estimating the need for supplemental irrigation supply, a shortage of 27 percent (about one-half acre-foot per acre) is assumed for all lands not served by storage. Using this factor, the northwest tributary lands would require approximately 65,000 acre-feet of water annually for a full supply.

Storage is required to provide that late-season water. However, the amount of storage developed in any basin may be up to three times the supplemental need for water on the crops. That is, providing 65,000 acre-feet of water to the field for consumptive use would require up to 195,000 acre-feet of storage. The reason for this increase is to make up for losses, other uses, and inefficiencies in delivery associated with normal irrigating practices. Reservoir evaporation, minimum flow and prior rights bypasses, recreation or environmental minimum pool requirements and conveyance losses all conspire to remove water from the headgate prior to application. As a recent example, High Savery Reservoir is designed with a maximum storage of 22,400 acre-feet. When all uses and losses are considered, the amount estimated as reduction in irrigation shortage is less than 7,000 acre-feet when the reservoir is in operation.

Therefore, supplying water for late season supplemental supply and the possibility of storage are major considerations in evaluating future agricultural demand. The following discussion describes the current reasoning behind the development of low, moderate and high-growth scenarios for agriculture:

(to 2030)









Mr. Tyrrell then made presentations reviewing projected uses, for low, moderate and high growth scenarios. These uses were broken down by type, i.e. municipal, industrial, agricultural, recreational and environmental.

The next topic discussed was the criteria with which future water use opportunities would be ranked. At the September BAG meeting two possibilities were put forth. One was a draft list of six criteria prepared by Mr. Tyrrell that was derived from opinion surveys and previous work. The other consisted of reproduction of parts of a 1990 document entitled "An Analysis of Contemporary and Historical Economics Associated with Water Development Projects in Wyoming" by David Brookshire, Ronald Cummings and Gary Watts. The BAG was asked to review these sources and prepare to discuss such criteria at the October (current) meeting.

The ranking criteria prompted much discussion. Among the opinions presented were that to create any project, it must first have a sponsor and be capable of funding assistance because without a reasonable chance of construction a project should not be ranked highly. This criteria is suitable for publicly-funded projects but would not apply to privately financed projects.

At the conclusion of discussion the criteria were still not set, but Mr. Tyrrell indicated the consulting team would take the various comments into consideration and present a refined set of criteria to the BAG at the November meeting.

Additional Presentations

No additional presentations were made.


The meeting was adjourned at 8:20 p.m.