Lutsen Water Supply
Water Supply Line from Lake Superior
LHB was hired by the Lake Superior/Poplar River Water District in Lutsen, MN to design a new water withdrawal system from Lake Superior. The new water system is used for snowmaking at Lutsen Mountains, to irrigate the Superior National Golf Course, and as a drinking water supply for the district. The water system uses a 36-inch diameter HDPE intake pipe extended 350-feet out into the lake to withdraw water. The lake water enters a concrete pit that was constructed 25-feet deep into the bedrock on the Lake Superior shoreline.
The water is withdrawn from the pit using three, 2,500-gallon-per-minute rated vertical turbine pumps that lift the water 425 vertical feet over a 2.1-mile distance to the Lutsen Mountain ski area and discharge the water into two open storage ponds. The water in the storage ponds is used for snow-making operations on the ski hill. Line taps are provided for irrigation of the golf course and supply of water to a drinking water treatment facility.
Snow Making Water Storage Pond
The system includes a 36-inch-diameter intake pipe extending into Lake Superior from a new pumping facility that delivers the lake water to two water storage ponds used for making snow at the Lutsen Mountains ski area and to a new water treatment plant at Caribou Highlands.
24-inch diameter HDPE force main pipe
The force main piping is a combination of 24-inch and 20-inch-diameter HDPE pipe extending approximately 11,000 linear feet from the pump house at the lake shore to the Lutsen Mountains ski facility approximately 425 feet above the lake elevation.
Pump House on the Lakeshore
A pump house constructed on the lake shore houses three vertical turbine pumps that extend down into the below grade pit. The pit is constructed approximately 32 feet below the pump house requiring blasting and removal of rock to a depth of approximately 25 feet.
Intake pipe installation in Lake Superior
Precast concrete anchorage walls were submerged and linked together to form a tray along the lake bed. The HDPE intake piping was inserted in the tray and concrete was placed around the pipe in the tray to form a solid concrete encasement of the pipe on the lake bed.
Intake pipe installation in Lake Superior
Precast concrete anchorage walls were linked together on the lake bed to form a tray in which the intake pipe was placed and held in place while concrete was poured between the anchor walls and around the pipe to form a solid concrete encasment of the pipe on the lake bed.
Intake pipe installation in Lake Superior
Large, precast concrete, anchor blocks with rollers to aid in the pipe insertion, were linked together end to end on the lake bottom. The pipe was then inserted into the tray, which secured the pipe to the lake bed and created a form for pouring a full concrete encasement of the pipe.
Construction of the pump pit
The pump pit was a cast-in-place concrete vault constructed down below the lake level. 25 feet of bedrock was removed on the shoreline to allow construction of the pit. The intake pipe was extended out into the lake from the pit. The pumphouse was constructed at grade directly above the pit.
24-inch diameter HDPE force main piping
Approximately 11,000 linear feet of HDPE forcemain piping was fused together and installed between the pumphouse at the lakeshore and the snow-making ponds at the Lutsen ski area. The force main piping traversed below two golf courses, a trunk highway, a state trail, and the Poplar River.
