SEH provided Level II analysis, feasibility design and cost estimating for a proposed 750 acre-foot raw water storage facility for the Bridger Valley Joint Powers Board water treatment plant located near Mountain View, Wyoming. The proposed storage reservoir will be contained by a homogeneous earth dam located on an upland terrace approximately 90 feet above the adjacent Smiths Fork River. The reservoir floor and embankment slopes will be covered with a geocomposite liner to minimize loss of high-value stored water and promote stability of the high slope immediately below the western side of the dam and reservoir. The reservoir will be supplied by pumping from a new plant adjacent to the river and tapping an existing WTP supply pipeline fed by a gravity diversion upstream. A new outlet structure and pipeline connection will facilitate releases back to the plant.

Features

• Earth dam - 6000 feet long, 40 feet high at tallest section, 500,000 cubic yards of earthfill and riprap
• Internal filters and drains, and a toe drain seepage collection and discharge system (with capability to add pumpback to the reservoir)
• Geocomposite liner (GCL) – approximately 2,000,000 square feet
• Pumping station/inlet pipeline – 300-2085 gpm pumping capacity range; three variable speed pumps operating at 75 feet TDH
• Outlet works/delivery pipeline – trashrack protected outlet structure with two hydraulically operated sluice gates (allowing reservoir draw at two different levels)

SEH Services

• Survey
• Geologic/geotechnical site investigation (drilling, water testing, test pitting)
• Environmental evaluation (focused on potential wetlands impacts)
• Permitting and mitigation evaluation
• Feasibility-level design
• Cost estimating