The Shoshone Business Council Onsite Wastewater Treatment Systems is located on the Wind River Reservation 18 miles north of Lander, Wyoming. The effluent discharges to the Trout Creek. The system utilizes both a surface flow constructed wetland (1.6 ac) in combination with wild fowl lakes (1.2 ac).

Design conditions are:

1. Design Water Temperatures - Winter 34F, and Summer 59F
2. Average Annual Precipitation - 12 inches
3. Design Flow - Average 185,000 gpd Peak 348,000 gpd
4. Project Location - 18 miles north of Lander, WY (Elevation 5,452 ft.)
5. Restrictions - High water table existing lagoons.

DESIGN OBJECTIVES - Develop a treatment unit to maintain BOD and TSS below 30/30 permit levels.

• Provide Surface Flow Wetland Cells - Meet Wyoming water quality permit levels.
• Provide Add-on to Existing Lagoons - Work with utilities staff to design surface flow wetlands and wild fowl habitat lakes.
• Provide for Soil/Clay Lined Treatment Units in a High Water Table - Discharge is into the adjacent creek.
• Consideration had to be given to seasonal groundwater levels.

BENEFITS

• Construction Cost (1994): Wetland - $168,900; Wild Fowl Lakes - $17,400.
• Land Consumption: only 3.5 acres.
• Habitat: conditions will support numerous wildlife species.
• Educational Forum: provides educational opportunities for local schools.
• Aesthetic Benefits: plants merge with existing riparian setting.