July 14, 2010
DNR to erect mesh barrier to block Asian carp
The Indiana Department of Natural Resources will take a lead role in implementing a short-term step to address the advance of Asian carp up the Wabash River system and their potential movement into the Maumee River, a tributary to Lake Erie.
The focal point is Eagle Marsh, a 705-acre restored wetland near Fort Wayne that DNR staff identified as a possible pathway for Asian carp passage under certain flood conditions. The marsh is just north of Fox Island County Park near the intersection of Interstate 69 and U.S. 24.
A permanent solution to prevent Asian carp from being able to pass through this area during flooding conditions will take more time to develop, design and construct.
Therefore, as an immediate preventive measure, the DNR will install mesh fencing across a section of the marsh, creating a barrier against passage of Asian carp between the Wabash and Maumee drainage basins.
The DNR convened a recent meeting in Fort Wayne to address the potential carp movement and explore solutions, and the consensus was the mesh barrier is the best short-term option to pursue. The Environmental Protection Agency, U.S. Army Corps of Engineers, U.S. Geological Survey, U.S. Department of Agriculture Natural Resources Conservation Service, the Allen County Soil and Water Conservation District, and the Little River Wetlands Project that manages Eagle Marsh, were represented at the meeting.
The fencing will be substantial enough to withstand floodwaters but will be designed so it does not increase flood elevations and cause property damage. The U.S. Army Corps of Engineers will provide design guidance on the fencing. The goal is to have the fencing installed this summer. Additional monitoring will be conducted and more aggressive action taken if the threat warrants.
Although Chicago waterways remain the likeliest entry point for Asian carp into the Great Lakes, the Corps of Engineers is tasked with finding other potential pathways throughout the Great Lakes basin. Corps officials have identified several sites they are investigating to determine the risk of Asian carp advancement, including the Eagle Marsh area.
Although the Wabash and Maumee basins drain in opposite directions and have no direct connection under normal conditions, their waters do comingle under certain flood conditions.
Eagle Marsh straddles a natural geographic divide created by glacial movement during the ice age. The broad wetland marsh extends across the divide into two key drainage ditches - McCulloch Ditch and Junk Ditch. McCulloch drains west into the Little River and eventually the Wabash River near Huntington, while Junk Ditch drains northeast into the St. Marys River and then the Maumee River.
If Asian carp cross the divide at Eagle Marsh and reach the Maumee, they would be in the Lake Erie drainage basin and additional more costly and invasive steps would be required to protect the Great Lakes from the threat.
The DNR and the Corps of Engineers are working with U.S. Geological Survey to analyze historic flood data and determine the depth and duration of flooding in the Eagle Marsh area.
Asian carp, a generic term for four species of non-native carp, were first detected in Indiana in 1996 at Hovey Lake Fish & Wildlife Area in the southwest corner of the state. Subsequent DNR surveys located bighead carp and silver carp in low abundance in the Wabash River or its tributaries, but the location of those findings show the fish moving upstream. A 2008 survey collected a total of 25 silver carp and two bighead carp over a 105-mile stretch of the Wabash River.
Adult bighead carp have been found below the dam at Roush Lake near Huntington, and silver carp have advanced to the Mississinewa River near Peru. In late May, a DNR biologist found evidence of silver carp spawning near Lafayette, 105 river miles downstream from the mouth of the Little River.
NOTE: For a map of the Eagle Marsh area, go to www.in.gov/dnr/fishwild/files/fw-AsianCarpMap.pdf
For facts about Asian carp in Indiana, go to www.in.gov/dnr/fishwild/files/fw-AsianCarpAdvisory.pdf
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