Ryan Sands, project manager of the J.F. Brennan Com. Inc.’s Lake Redwood dredging project, took KLGR on a tour of the dredge.
The Lake Redwood dredging project is about halfway through, and KLGR went on a tour of the dredge, the Michael B., recently.
The dredge, the Michael B. is two separate connected platforms, back barge is booster pump.
The Michael B., the second largest dredge in J.F. Brennan Company, Inc.’s fleet, arrived in Redwood Falls on April 12. Dredging began the afternoon of April 21. To date, a bit over 300,000 cubic yards of sludge have been pulled out of Lake Redwood.
The project manager, Ryan Sands, of the La Crosse, Wisconsin-based J.F. Brennan Company, Inc. took KLGR News Director Joshua Dixon over to the Michael B. to see how it works.
We intended to write a detailed article about what Mr. Sands told KLGR, but he explained it so well we decided to let him to most of the talking. There is background noise of the various boat and pump engines throughout this interview, but we decided the dialogue is clear enough to understand.
The dredging operation is fully manually controlled; nothing is on automation. The cab’s controls show a 3D view of the lake bottom, based on surveys and sensors on ladder.
Our interview started in the small boat on the way out to the dredge, with Mr. Sands explaining how the dredging project is staffed:
The view from the cab: the Michael B. was removing an island from the center of Lake Redwood the day KLGR visited.
What has the crew found so far out on the lake?
The cutter spins and agitates the material, taking the material out one layer at a time. Then the ladder suctions out the sludge and pumps it. The crew was taking out layer of island about 10 feet down when KLGR visited.
What does the material from the bottom of the lake feel like?
The dredge has struts that hold it in place as it is working.
The dredging crew has removed three islands of sediment so far. How deep is the water at this point?
Sludge from the bottom of the lake goes first goes through an 800 hp pump in the “basement” of the dredge, then past a 1,000 hp booster pump on the back. When it reaches shore, the sludge is piped past two booster pumps before arriving at the confinement site.
How does the crew decide where to dredge under the surface on any given day?
The dredging operation is diesel powered, going through about 2,400 gallons a day, or 100 gallons an hour.
How will the crew know when the job is finished?
Tree trunks in the lake are being moved close to shore, where they’ll be removed by the City of Redwood Falls eventually.
Now we get to a crucial question: at its worst, was it possible to actually walk across Lake Redwood?
A crew from J.F. Brennan Co. Inc. has set up onshore, and is manned six days a week until the project is finished.
Have spectators watching the progress been any trouble?
If things go well, the dredging should be done by the end of October, with disassembly of the pipeline going beyond that.
