Wyoming Framework Water Plan - Living Rivers Home Page

8.0 OPPORTUNITIES
Cottonwood Creek Drainage (Mickelson Creek Off-Channel Reservoir)
One project, the Mickelson Creek Reservoir, has been identified as the best alternative to meet
the needs in this drainage.
This potential storage project is off-channel and would require an approximately one-mile
diversion canal from South Cottonwood Creek. The proposed storage capacity was 7,300 acre-feet. This
project, although mid-range in scoring and cost, is the best alternative in the drainage. A Level II study
would be needed to determine the feasibility of this project. The potential for a multipurpose reservoir
should be investigated.
Horse Creek Drainage (Horse Pasture Draw Off-Channel Reservoir)
One project, the Horse Pasture Draw Reservoir, has been
identified as the best alternative to meet the needs in this drainage.
This potential storage project is off-channel and would require an
approximately one-mile diversion canal from North Horse Creek. The
proposed storage capacity was 5,710 acre-feet. This project is in the
mid range in scoring and costs but is the best alternative in the
drainage. A Level II study would be needed to determine the
feasibility of this project. The potential for a multipurpose reservoir
should be investigated.
Beaver Creek Drainage (Cow Gulch Off-Channel Reservoir)
One project, the Cow Gulch Reservoir, has been identified as the best alternative to meet the
needs in this drainage. This potential storage project is off-channel and would require an approximate
four and one-half mile canal to divert water from Middle Beaver Creek and South Beaver Creek. The
proposed storage capacity was 13,330 acre-feet. This site was not highly rated but is the best alternative
identified in the drainage. A Level II study would be needed to determine the feasibility of this project.
The potential for a multipurpose reservoir should be investigated.
8.4.9 Future Groundwater Development
There is virtually no information on the overall groundwater basin water budget, such that major
inflow and outflow components may be quantified. Accordingly, it is difficult to evaluate the Green River
Basin’s safe, long-term yield for purposes of defining future groundwater development potential.
The basin has a total area of about 20,000 square miles (12.8 million acres). However, there are
large areas of the basin in which potential evapotranspiration (ET) significantly exceeds average rainfall.
For purposes of this analysis, it is assumed that recharge is effectively zero in areas where ET
significantly exceeds rainfall. In the remaining parts of the Basin, mainly the mountain and foothills areas,
rainfall exceeds potential (ET). These areas have been mapped and are estimated to have an area of
approximately 925,000 acres. The average “surplus” rainfall (where annual rainfall exceeds annual ET) is
assumed to be about 6 inches. It is also assumed that approximately 10 percent of the surplus rainfall
recharges the groundwater system. This approach yields an estimate of about 50,000 acre-feet per year of
groundwater recharge, which is considered to be an approximation of basin groundwater yield. These
estimates neglect the potential for interbasin movement of groundwater. They also neglect the large
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