Wyoming State Water Plan, Wyoming Water Development Office
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Platte River Basin Advisory Group
Meeting Record
Rawlins, WY
October 5, 2004

Facilitator Sherri Gregory welcomed the group and called the meeting to order at 10:00 am. Sherri asked those in attendance to introduce themselves and reviewed the meeting agenda. A sign-in sheet was circulated to record attendance. The next Platte River Basin BAG meeting will be held on Tuesday, December 14, 2004 at 10:00 am in Wheatland.

Planning Team Issues
River Basin Planning Update:
Barry Lawrence, WWDC, noted that three of the other basin plan BAGs had met the previous week and three BAGs will meet during the week following this BAG meeting. Meeting locations from the previous week and discussion topics included:

Platte River Cooperative Agreement
Mike Besson, WWDC, discussed the Cooperative Agreement. Mike stated that endangered species issues drove the need for this agreement. The original 1945 Platte River Decree over-appropriated the water in the basin. The new demand associated with endangered species is 35,000 AF. The Pathfinder Modification Project is to address this. Comments on the EIS were due September 20, 2004. All comments received concerned the upper Platte River Basin. Lower basin water users realized they had exposure from the NEPA requirements since they deal with federal contracts, so they generally support the program. Upper basin water users have difficulty understanding how they and their water rights may be impacted. The largest impact identified was to the Alcova Irrigation District. Impacts to the upper basin are based on an allocation year from February to April and on those that may irrigate during those months.

What is next? The three states; Wyoming, Nebraska, and Colorado; will provide input for the Biological Opinion (BO) required by the US Fish and Wildlife Service. States will provide assistance relative to specific issues to document that the BO provides a reasonable and prudent alternative. Areas of disagreement include:

All of the Wyoming State parties involved with this project agree that the original 1945 Platte River Decree and the Modified Decree should not recognize a call on the river after May 1. The Wyoming Attorney General.s opinion concurs with this point of view and is available on the State of Wyoming web site.

An item discussed with the Governor was provision of an escrow account to provide financial recourse for those impacted by a post-May 1 call should such a call be made. This scenario could allow a landowner that would not be able to irrigate as a result of a post-May 1 call the opportunity to receive reimbursement for lost or damaged crops.

The current EIS schedule is:

Consumptive Use Study
Phil Stump from the State Engineer.s Office briefly discussed the questionnaire that is being sent to approximately 5,000 North Platte irrigation water users above Guernsey Reservoir. The data requested include types of irrigation methods used, crops grown, grazing practices, etc. The purpose of the questionnaire is to try to assess whether there have been changes in irrigation practices by landowners above Guernsey Reservoir. The goal of the project is to test the data received from the questionnaire against prior assumptions used to calculate consumptive use since there is currently no historical data with which to make this comparison.

North Platte Groundwater Assessment Study
Joel Farber of Trihydro Corporation presented the results of work to date on the groundwater assessment study. Wyoming is obligated to replace or augment the flow of the North Platte River at Whalen Dam to offset depletion in the triangle area in the lower part of the basin. The triangle is identified by the area bounded by the Interstate and the Gering Ft. Laramie Canals below Whalen Dam. The North Platte Groundwater Assessment Study is to identify potential sources of augmentation water, particularly 8 to10 thousand acre-feet of groundwater that is not hydrologically connected to the North Platte River. The definition of a .hydrologically connected groundwater well. is a well that is located and constructed such that, if water were intentionally withdrawn continuously for forty years, the cumulative stream depletion would be greater than or equal to 28 percent of the total volume of groundwater withdrawn by that well.

The scope of work for this project included performing a reconnaissance level investigation of the geology of the entire basin to develop a .long list. of prospective groundwater reserves. Screening criteria were developed to shorten the long list from 73 sites to approximately 10 prospective locations that could produce groundwater throughout the year.

The screening criteria were reviewed in detail. Some of the criteria included engineering factors, geologic factors, miscellaneous factors, and costs. For example, conveyance losses from potential prospects to Whalen Reservoir were calculated and factored into the ranking analysis. The costs of producing and conveying the water were also calculated and factored as part of the screening.

The screening process involved looking at the aquifer systems in the basin, then looking at the locations of high-yield wells. The analysis of these high-yield wells led to the production of a high-use aquifer map. A high-use aquifer may need to be avoided as an augmentation source due to possible impacts to existing groundwater users. Annual precipitation was reviewed in conjunction with the aquifer map to understand the hydrologic system of an area and the relationships between recharge zones. Land ownership was reviewed to identify potential well field sites that may or may not be located on public lands. Conveyance losses were calculated on a percentage loss per mile basis. Existing surface and groundwater rights were also investigated to determine if there were any conflicts to existing rights. Water quality parameters were also important factors in the selection of potential water supply sources.

The 10 prospective locations were then reduced to three locations for development of conceptual level analysis and design. Exploration programs were developed for these three locations. The study concluded by focusing on two sites after one of the three final locations was eliminated as a result of more detailed analysis. One of the two final sites was at Split Rock, and the other was on the south flank of the Shirley Mountains.

The Split Rock groundwater exploration program was discussed as one of the finalists for development of a well field. A map was reviewed that showed the recharge area, the surface topography, and the bedrock in the vicinity of the prospective wells. The anticipated depth of a well at this site would be approximately 3,000 feet. The static water level is approximately 150 feet below the surface, resulting in a significant thickness of potential water bearing unit. The next step discussed was how to convey the groundwater to its point of intended use at Whalen Dam. The conveyance losses resulting from overland flow versus utilization of a pipeline are being evaluated.

Currently, plans and specifications are being developed for construction of a test well and monitoring wells. This construction project is tentatively scheduled for bidding during November 2004, with construction to occur during the winter of 2004 - 2005. Permitting for this work is almost complete as are land access agreements.

A conceptual study of two pipeline routes is ongoing, including routes from:

This study involves the creation of a land ownership map of the area to determine if the pipelines could be sited on public land rather than on private land. It is assumed that, if the pipelines are located on public lands, access permits for construction and maintenance will be easier to obtain than if the pipelines are located on private lands.

Mr. Farber also discussed the status of the Platte River Basin Plan web site, the Platte River Water Atlas, as an educational tool for the general public to utilize. Information and changes to the format of the data were discussed. Sensitivity of certain information and utilization of information that is in the public domain was also discussed.

The BAG adjourned at approximately 1:00 pm.