For Citizens Energy Group, a Design-Build project used a quarry near Geist Reservoir to create a 225-foot deep, three-billion-gallon water storage reservoir. This reservoir supplements downstream water treatment plants during droughts. High flow water from Geist Reservoir enters the quarry through an intake structure and an 8-foot wide, 220-foot deep concrete drop shaft, then a 240-foot long tunnel. During dry periods, water is withdrawn via a 467-foot long tunnel on the opposite side, using 600 horsepower pumps, and conveyed through a 30” force main to the intake structure 3,050 feet away.

Wilhelm was involved from 60% design completion to improve constructability. Value engineering included switching the force main material to PVC, adjusting alignment to reduce excavation depth, and increasing pump shaft bore diameter. Revising foundation support and using micropiles accelerated the schedule and reduced costs. Savings under the Guaranteed Maximum Price (GMP) were returned to the owner.