Operators at the Two Rivers (Wisconsin) Waterworks noticed flow restrictions in the 24-inch raw water intake pipe in Lake Michigan that limited production to 1.6 mgd, versus the water treatment plant’s 3 mgd design.
In late 2015, the Wisconsin Department of Natural Resources told the city to address the problem, which threatened the plant’s ability to meet emergency water demands. In May 2017, the city hired Hibbard Inshore of Auburn Hills, Michigan, to inspect the pipe using a SeaBotix LBV 600-6 MiniROV (Teledyne ISCO).
Divers saw layers of zebra mussels on the wooden crib across the intake riser. The 12 to
