When heavy rains hit Northwest Indiana, many eyes focus on the level of the Little Calumet River. Water from the river inundated several communities during the floods in 2008 and 2007, caused millions of dollars in property damage and stressed the need for the completion of a levee system stretching from Munster to Gary.
But part of the levee system — a diverter that pushes water from Hart Ditch and the river eastward near Wicker Park in Highland — hasn’t been working to the level the U.S. Army Corps of Engineers estimated, according to Purdue University Calumet researchers. The diverter is supposed to send the flow eastward toward Highland, Griffith and Gary — at a rate of 35 percent — where pumping stations and storage detention ponds have been constructed to hold the water during storm events.
Recent data analysis completed by PUC civil engineering professor C.V. Chandramouli and students confirmed via three-dimensional modeling that the water was being moved at a slower than estimated pace. The diverter actually increases the flow on the east branch of the Little Calumet by 10.6 percent and decreases flow on the west branch by 11.3 percent. There was no significant change in flow at Hart Ditch.
Dan Repay, executive director of the Little Calumet River Basin Commission, said it was pretty clear that the diverter wasn’t increasing the flow eastward.
“It appeared when it was complete in 2012 that it wasn’t working the way it should,” Repay said. “We did video of a high water event, and it didn’t look right. It should be bigger variance.”
Through happenstance, Chandramouli — a Munster resident — wanted to do a research project on the flow of the Little Calumet River and approached the town council in Munster, which connected him with Repay.
Chandramouli’s research team determined that additional measures were needed for the diverter to work to its expected capacity.
High velocity channel
A recent addition to the river — a high velocity channel — has helped improve the flow since it was finished in July, Repay said.
“We developed a high velocity channel, so under higher flow conditions, the water will flow to the east,” Repay said. “When it rises in Hart Ditch, we’ve built a path where it does flow east, helping to enhance the water going east — what the Army Corps intended.”
The $857,500 project was done by the commission, but it did require approval by the Army Corps, Repay said.
“With the channel being built, we’ve solved the problem to an extent,” Repay said.
The commission also moved a silt island on the river just east of Kennedy Avenue to improve flow as well. Repay said the island used to have a bunch of trees in the middle of the river, but they pushed it to the north, along the banks that abut the Wendy’s parking lot.
He said the commission has looked at other maintenance options, such as dredging.
“I think with dredging — a lot of people think that’s a good solution,” Repay said. “But when you go along Hart’s Ditch, you see the backyards and the erosion that would just continue to happen. It really slows the water down upstream. The same can be said for Deep River, which has issues with Lake George silt.”
Chandramouli and his research team want to continue their research into Illinois and eastward along the Little Calumet and to Burns Ditch. They recently applied for a grant through the National Oceanic and Atmospheric Administration’s coastal program.
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