ROCK FALLS – With 100 miles of canal and 200 miles of levees, the No. 1 priority for the Hennepin Canal occupies less than half the width of the canal, and it’s in Rock Falls.
That’s the word from Bob Appleman, programs manager for Illinois Department of Natural Resources as well as the deputy state historic preservation officer and director of the Illinois Office of Realty and Capital Planning.
The Hennepin Canal staff and state overseers have plenty to be concerned about, ranging from beaver dams in drainage areas threatening the canal levees with possible washouts during flash flooding to not having a suitable trailer to transport heavy equipment to do canal levee repairs to prevent breaks.
But Appleman considers the top priority fixing, unfreezing or replacing the “guard lock” at Rock Falls.
“It’s actually a water-control gate,” he said of the small gate and mechanism that moves it to regulate the amount of water that enters the feeder canal that provides water flow from the Rock River into the canal. “It’s the control mechanism we’re having trouble with.”
Without the ability to shut off the water entering the canal, if there’s a break downstream in the feeder canal or the eastbound or westbound main channel of the canal, millions of dollars in collateral flood damage could occur to private or public properties alongside the canals.
If the state can easily shut off the water flow from the Rock River, it can halt the flow to make repairs and limit damage to neighboring properties, said Appleman.
Without that ability, the state has to find contractors to build a water bypass system for hundreds of thousands of dollars – which happened this winter and spring after a washout east of Tiskilwa – before it can make repairs.
Appleman has no estimate of what it might take to fix or repair the gate. It could be $50,000, it could be $250,000, it could be more.
“We need to evaluate how much of the structure needs to be fixed,” Appleman said.
Over the next month or two, Appleman and the state will advertise for and find an engineer to evaluate the issue.
It’s not a typical engineering evaluation, he said.
Someone will need to dive below to evaluate the gate, and when repairs take place, a contractor probably will need to put in a temporary coffer dam to limit the amount of water that gets into the work area.
“This is not that simple of a project,” Appleman said. “It’s not like fixing a spigot on the outside of the house.
“Is it a replacement? Is it ice damage? Rust?”
Whatever the case, Appleman emphasized the importance of controlling water flow at its source.
“It’s a valuable maintenance item we need to have in place,” Appleman said.
A DNR spokesman referred comment to Appleman last month but stated, “I can tell you we have to move through the selection and planning process yet, but hopefully will be able to move forward with repairs in the spring.”