“WHAT IS A ‘MORAINE’?”
Answer: A mound of earth varying in size, from deposits made by a retreating glacier when it pauses in its retreat for a number of years.
BENDS OF THE WABASH
From Piracy in a Watershed, by Richard Poor, former Elmhurst High School math teacher
Some 130,000 years ago the Illinoisan Glacier covered most of Indiana almost to the Ohio River, leaving the basic topography of Northern Indiana much as it is today. Through the Fort Wayne area there was a ‘height of land’ that divided drainage from the St. Lawrence system (present day name) from the Gulf of Mexico system. This continental divide was not dramatic; estimates are that it was only about four feet! Not very high for a continental divide. Efforts to find estimates of surface drainage features after the retreat of the Illinoisan glacier have been fruitless for me.
Some 110,000 years later another world cold spell spawned the Wisconsin Glacier, which advanced into Indiana roughly some miles south of present day Indianapolis. The Saginaw and Erie Lobes of the Wisconsin glacier left a number of fairly dramatic moraines as the warming trend some 15,000 years ago caused their retreat.
One of these moraines existed near the previous continental divide along present day western Fort Wayne.
As the glacier paused there in its retreat, two frontal drainage rivers flowed southwest along its front and another flowed northwest along the front. These two melt water drainages joined and flowed southwest toward the present day Ohio River. The two frontal melt water rivers were present day St. Joseph and St. Marys Rivers, which when joined formed our Wabash River! As glacier melting continued, the area NE of Fort Wayne and into present Michigan and Ohio began to fill up with water, forming Glacial Lake Maumee. (What is left of it is Lake Erie).
As the water filled the lake, pressure was created on the Fort Wayne moraine, until at some point a breach was made, apparently in some low spot, and the water began to spill out southwest into the Wabash, causing erosion of the moraine and enlarging the breach.
This effectively drained much of Glacial Lake Maumee. Some scientists claim that the ‘Torrent’ that occurred, drained most of the lake in a matter of two weeks. Others believe it took much longer. I tend to agree that it took longer, for during the world warming trend the melting glaciers would continue to fill the lake and drain from the Fort Wayne Moraine, perhaps for more than a thousand years.
Thus the Wabash watershed included all that of the St. Joseph and St. Marys, and our Little Wabash River was the main Wabash for a long time, and the ‘other’ part of the Wabash, extending into Ohio was only a small tributary.
Of course, when Glacial Lake Maumee got low enough and the breach or notch in the moraine wore down enough, the St. Marys and St. Joseph were headed off by the previously mentioned Illinoisan continental height of land, and began flowing back northeast into the now drained Lake Maumee and formed the Maumee River. This completed the piracy of the rivers and two entire watersheds!
Today if you travel down Ohio State Road 49, and cross the ‘Wabash River’ it is only a small ditch. But the Wabash valley in southwest Allen County is still visible today, from the torrent of water which helped to‑form it.
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