Posted on June 21, 2023
There is a lot of dredging work to be done in Lake Michigan harbors after an uptick in severe storms and a drop in shoreline ice during winter.
The U.S. Army Corps of Engineers currently is overseeing 24-hour dredging in Grand Haven when weather is favorable to remove sand shoaling that blocks the harbor from commercial vessels. Workers are doing overtime because unusually windy and wavy conditions delayed prior dredging in Holland.
Unprecedented shoaling – when sand moves into a channel – led to additional dredging needed in Holland, where contractors moved 90,000 cubic yards of material before shoving off for Grand Haven. Now the goal is by mid-July to clear 141,000 cubic yards of sand from the channel in Grand Haven, as commercial docks there are struggling to receive shipments because of the shoaling.
“We’re dredging later than planned but looking forward to the safe opening of the harbor to commercial shipping very soon,” said Elizabeth Newell Wilkinson, the Corps’ Grand Haven resident engineer.
Yet Grand Haven and Holland aren’t the only Lake Michigan shoreline communities struggling with the issue of sand movement beneath the waves.
The same freighter grounded twice on sandy sentiment near the Muskegon pier, both in April this year and April last year. The Corps sped-up plans to dredge the Muskegon harbor after the second grounding.
Passenger ferry service to both North and South Manitou islands was suspended in 2020 because of needed dredging near docks at both remote islands within Sleeping Bear Dunes National Lakeshore.
And none of these examples are surprising to those who study coastal dynamics on the Great Lakes.
It makes sense that more than one recent winter with low ice conditions would lead to a lot of sand movement in the near-shore areas, said Mark Breederland, a sustainable shoreline expert with nonprofit Michigan Sea Grant.
“With no shore ice out there, I’m sure that there could have been longer wave action kind of moving that sand through the mouth of the harbors,” he said.
“It is common sense when we have no shore ice, there’s more shore erosion, there’s more sand that gets into the system, and then the sand can move – is always moving. We call the Great Lakes the rivers of sand, especially here on our Lake Michigan side where we don’t have the rock like they have on the Lake Huron side.”
Breederland said it’s an important question whether the expectation of warming temperatures and less Great Lakes ice cover combined with stronger storms fueled by climate change will lead to more erosion and sand shoaling problems.
Nearshore hydrodynamics expert and Michigan Technological University Professor Guy Meadows it almost certainly will.
“We know for a fact that storm intensity increases and waves increase and that moves more sediment around, so it’s not a big surprise that the Corps of Engineers is behind in their dredging,” Meadows said.
“We see lots of sediment in motion now coming off of the high water we just experienced in Lake Michigan and all the shoreline changes that occurred as a result of that. All of that contributed more sediment to the near shores.”
The scientist also said the lack of winter ice has a tremendous effect on moving sand and sediments in waves.
Meadows also said this isn’t just a problem for the commercial shipping industry; these conditions also can lead to dangerous nearshore currents called rip currents, which can develop quickly with deadly consequences.
Additionally, Corps officials said beachgoers in Grand Haven should stay behind the safety cones and avoid getting too close to the dredging pipeline at the discharge point. Sand and water are pumped through the pipeline and create an almost quicksand-like condition directly around the pipe outfall.
A bulldozer will regularly grade the deposited sand.
