The project's design allowed the existing lift station to remain in use during construction to minimize disruption to area residents.
Carlson Lake Lift Station
City of Eagan, Minnesota
One of Eagan's lift stations, Carlson Lake lift station, required updates to meet city standards. Although the city desired a submersible lift station with a valve vault, the soils could not support the installation of a precast manhole. Bolton & Menk designed and installed screw piles to support the new valve vault. The lift station was located exclusively in the right-of-way and near residential homes. Typically, the existing dry well can is removed and a precast structure installed in its place for a new submersible structure. In this case, excavation of more than 20 feet was required; however, this deep excavation would expand into the yards of area residents and there was a desire to minimize disruption.
Bolton & Menk's design allowed the existing station to remain in use during construction. The design also addressed the city's safety and maintenance concerns. Bypass pumping was used while the contractor installed the fiberglass insert and valve vault. New pumps and controls were installed and the area was landscaped upon completion. The lift station now meets the city's lift station standards, making the station safer and easier to operate and maintain.