FORT WAYNE, INDIANA — Recently, I travelled to Eagle Marsh to see first hand what construction of a $1.9 million berm will look like at a vital passageway between the Mississippi River basin and Great Lakes watershed. It is here where researchers with the Indiana Department of Natural Resources and engineers with the federal Army Corps believe Asian carp may move from the nearby Wabash River (part of the Mississippi River basin) into the Maumee River which drains into Lake Erie.
In October 2010, after less than a year of site visits, risk analysis and consultations amongst federal agencies, a $300,000 chain-link fence with openings no larger than two inches was constructed with the aim to keep Asian carp from moving between the basins. The fence, however, was never intended as a permanent solution but a stopgap until a more formidable option was decided upon by local, state and federal authorities.
In January 2013, an option was decided upon to build a berm beside an existing earthen berm capable of withstanding a 50 year to 100 year flood. At 10 feet high and more than 80 feet wide at the base, the new berm is slated to provide protection against Asian carp ever moving between the basins while also offering flood protecting for the nearby residents of Fort Wayne.
Eagle Marsh is now listed behind only Chicago for areas where Army Corps officials believe Asian carp may spread to the Great Lakes. Silver and bighead carp have been found in the nearby Wabash River which runs throughout much of Indiana, though to date no Asian carps of any variety have been found in the Little River which flows into the Wabash.
How the Interbasin Transfer Could Happen
Historically, the Little River Valley (where the 716-acre Eagle Marsh wetland is located in northeastern Indiana) has been a vital transportation passage for people moving from the Great Lakes region into the American South and West. The continental divide runs through Eagle Marsh, ensuring that all water to the west flows to the Mississippi River and onto the Gulf of Mexico while all water to the east will drain into the Great Lakes.
But now, what was once a tremendous asset for settlers and American Indians in the region is viewed as a liability for the transfer of aquatic invasive species. And the region, traditionally a wetland, is naturally prone to flooding. A 48 hour period in August 2014, for example saw the region suffer through a once every 1,000 year storm followed immediately by a once every 100 year storm.
Here’s how the Army Corps predicts the transfer could happen.
Without a permanent barrier in place, the Army Corps fears flooding from the Mississippi River basin could bring Asian carp into Eagle Marsh via the Little River and Graham-McCulloch Ditch, built as part of a 25,000 acre wetland drainage program throughout the mid 20th Century. Once established in Eagle Marsh, the invasive fish could remain once flood waters receded.
However, another drainage channel (known as the Junk Ditch) flows east from Eagle Marsh towards the St. Mary’s River. The St. Mary’s River is larger and also prone to flooding the marsh from the Great Lakes side. The Junk Ditch was built to provide flood relief for the marsh by ferrying water away and towards an upstream part of the St. Mary’s River at Swinney Park.
With Asian carp in the marsh, fish could be sucked up with the flow of fast-moving flood waters and soon find themselves in the St. Mary’s River having crossed the continental divide. From there, it’s onwards to Fort Wayne where, just east of downtown, the St. Mary’s meets and becomes the Maumee River that flows ultimately to the Great Lakes.
After my visit I made a four-minute video of the berm construction site as it exists in early March 2015, outlining what will be built and where. Once the snow melts, construction crews will begin moving in this spring with the aim of completing the new berm by September 2015.