The Wyoming Water Development Commission and the Wyoming Legislature’s Select Water Committee approved a Level II Storage Feasibility Study for the Middle Popo Agie River this month.
The study will focus on “enhancing storage capacity, understanding water management opportunities, and providing drought resiliency,” according to a funding recommendation from the Wyoming Water Development Office.
Low flows
The Middle Popo Agie River drainage “frequently experiences low flows and water shortages during the middle to late summer months,” the WWDO said, leading to “agricultural water shortages” and impacting “water quality, recreation, and fish and wildlife habitat.”
“The existing water supply from the Popo Agie River Watershed is not capable of fully meeting the requirements of all water users, especially in the Middle Popo Agie River,” the WWDO said.
Many of those water users have collaborated as part of the Healthy Rivers Initiative, which was established in 2016 “to build a working group that encompassed all stakeholders interested in water resources with the long-term goal of improving water quality and quantity within the Popo Agie River Watershed,” according to the WWDO.
WWDO Director Jason Mead called it a “grassroots effort” to “get a handle on (the) lack of water in the Middle Popo Agie River,” which affects everything from irrigation to recreation and water quality.
“It’s really a multi-purpose effort (to) look at increasing storage to take care of that issue,” he said.
Worthen expansion?
Two of the HRI collaborators – the Enterprise and Taylor Watershed Improvement Districts, both subdivisions of the Popo Agie Conservation District – are listed as the sponsors of the new Level II Storage Feasibility Study project, which “has the support from the entities involved in HRI,” according to the WWDO.
The sponsors “envision an expansion of Worthen Meadows Reservoir and efficiencies in the management of Frye Lake could be a solution to address limited late season stream flows and agricultural water shortages,” the WWDO said.
The City of Lander built Worthen Meadows Reservoir in 1960 to provide a long-term municipal water supply, according to the WWDO; it is located on Roaring Fork Creek – a tributary to the Middle Popo Agie River in the Shoshone National Forest – and is approximately 12 miles southwest of town.
“The reservoir stores approximately 1,500 acre-feet of water that is exclusively available to the city for municipal use,” the WWDO said.
In 2023, while developing a new water master plan, Lander “briefly analyzed” the idea of enlarging the reservoir “as a potential solution for future water shortages,” according to the WWDO.
“Based on preliminary analysis, it was concluded that it is theoretically feasible to enlarge (the reservoir), and the concept should be analyzed further through a Level II water feasibility study,” the WWDO said.
Twenty years earlier, a 2003 study had recommended irrigation improvements and analyzed 33 potential storage sites throughout the Popo Agie River Watershed, including the enlargement of Worthen Meadows Reservoir, the WWDO noted, with a follow-up study conducted in 2019 focusing on “micro-storage sites, with a target volume of 300 acre-feet, to provide alternatives that supplement the larger structures.”
Enterprise, Taylor
The Enterprise WID operates and maintains Frye Lake, which is supplied by a diversion off of Roaring Fork Creek about 1.8 miles east of Worthen, the WWDO said.
The lake has a capacity of 1,697.5 acre-feet and “provides irrigation water to the Enterprise WID, (which) serves 3,660 acres of irrigated agricultural land used to grow native grass and alfalfa for pasture and hay production,” according to the WWDO.
Meanwhile, Taylor WID irrigates 2,079 acres of land using direct diversion from the Middle Fork of the Popo Agie River, the WWDO said.
“Taylor WID, along with other Middle Fork irrigators besides the Enterprise WID, do not have any supplemental water supply from reservoir storage and rely on the natural runoff cycle of the river,” the WWDO said.
Local irrigators have “tried to help ourselves” address the “limited late-season water” problem by tackling “losses in our conveyance system,” Popo Agie Conservation District Member Doug Thompson said, but those efforts can be “difficult” and “costly” due to the “inhospitable” nature of the terrain above Lander.
The new study will assess those potential water conservation options and provide cost estimates that local irrigators can use to make “broad-based decisions” going forward, he said.
Mead agreed that the study will consider “a reasonable range of alternatives” for “conveyance efficiencies and application efficiencies,” then compare the estimated impacts of those potential efficiency measures with the potential impacts of providing additional storage via “a new reservoir” or “an enlargement to Worthen Meadows.”
The proposed budget for the new study is yet to be determined.
For more information, call the WWDO at (307) 777-7626.