Mussels Invite Malice in Dairyland

From March 23, 1993 (Update #16)

Hundreds of thousands of small zebra mussels were found throughout Dairyland Power Company's E.J. Stoneman power plant during inspections in mid-January, according to Dairyland Environmental Biologist John Thiel. Subsequent investigations turned up large densities of mussels in fire protection and service water systems at three other Dairyland power plants on the Mississippi River. Zebra mussels were first found in the plant in late October. Although Dairyland had hoped to use thermal treatment to control mussel infestations, Thiel said, the expense and delay needed to alter plant systems for thermal treatment may require them to initially rely on chlorine treatment of infested plant systems. Some small water systems may also be switched to groundwater sources. Thiel pointed out that conditions in the section of the Mississippi River in which Dairyland's plants are located - from Alma to Cassville - may be particularly well suited for zebra mussels. He said "beautiful" beds of native Unionid mussels are already present in some of their plant pumphouses and forebays, indicating favorable conditions for mussel growth. He also noted that sand in that part of the Mississippi River has allowed power plants to rely upon natural scouring to control algae growth instead of using chlorine, perhaps making the plants more susceptible to mussel infestations.

ID: 19930323-2.

The Zebra Mussel Update was a 4- to 8-page quarterly national newsletter published by the University of Wisconsin Sea Grant Institute from May 1990 through May 1997. The ZMU documented the spread of the zebra mussel -- an exotic nuisance mussel -- through North America's freshwater environments, especially the Great Lakes, and on efforts to control it.