Consultant's Report - Minnesota State Legislature

I. Introduction
Purpose
MINNESOTA DEPARTMENT OF NATURAL RESOURCES
Feasibility Study to Limit the Spread of Zebra Mussels from Ossawinnamakee Lake
In 2003, zebra mussels (Dreissena polymorpha) were documented in Ossawinnamakee Lake
(Crow Wing County, Minnesota). Subsequent sampling in 2004 indicated that the population
had become established and that natural reproduction was occurring. Ossawinnamakee Lake has
one outfall location that discharges into Pelican Brook, which is a small stream that flows
approximately 5.5 miles (8.85 kilometers) before entering into the Pine River. The Pine River is
a tributary ofthe Mississippi River. This flowing water path provides a means for zebra mussels,
particularly veligers, to move from Ossawinnamakee Lake into the Mississippi River and causes
a significant threat for dispersal ofthis harmful invasive species.
In 2004, a chemical treatment was applied to Ossawinnamakee Lake in an effort to reduce the
,
risk of zebra mussel spread from the lake to Pelican Brook. The treatment was applied to one
bay ofthe lake, Muskie Bay, on a weeldy basis. Following this temporary treatment, there was a
reduction in zebra mussels (MN DNR unpublished data). Although the treatment was effective,
many other aquatic species were harmed in the process. As a result, it was impOliant to explore
alternative technologies that would control the established zebra mussel population.
According the Minnesota Department of Natural Resources (MN DNR) Staff, the zebra mussel
population in Ossawinnamakee Lake is a threat that needs to be promptly addressed. The
Minnesota Department ofNatural Resources (MN DNR) has requested an evaluation ofpotential
technologies that would prevent or limit the in-water transport of zebra mussels, with particular
focus on peak veliger periods (May - September). This study, entitled Feasibility Study to
Limit the Spread of Zebra Mussels from Ossawinnamakee Lake, has been developed in
response to their request.
Scope of Work p
This study evaluated potential and available technologies that may be effective in managing
zebra mussel dispersal from both an enviromnental and engineering point of view. The specific
goal was to provide the state with an objective analysis ofthe effectiveness ofthese technologies
in preventing or limiting the in-water transport of zebra mussels from Ossawinnamakee Lake.
This study includes an assessment ofthe potential impacts ofzebra mussels, the effectiveness of
each technology in limiting the invading species, the environmental impact of each technology
on native species, the advantages and disadvantages of each technology, the time frames needed
to implement each technology, the potential ofthe engineering task to be successfully completed,
and an opinion ofthe cost ofimplementing each technology.
1-1
Introduction