Cause of seawall movement and boardwalk damage discovered
Mon, Nov 2, 2009 
to del.icio.us
BY ALEX DOTY
adoty@grandhaventribune.com
Workers from the U.S. Army Corps of Engineers have discovered what caused the channel wall along the Grand Haven harbor entrance to shift and damage a portion of the remodeled boardwalk.
"We did go down there (Wednesday, Oct. 28) and busted out a couple spots where the anchor heads are located," said Tom O'Bryan, Lake Michigan office area engineer.
After crews from the Corps opened up this area, they were able to find that the anchor heads had come loose from the bulbs which hold the anchor heads in place at the wall, which was built in the early 1980s.
"Once it lets loose, it is just sitting there," O'Bryan said of the wall, adding the wall can move a lot more freely than when the anchor head is attached.
Strong storms at the end of September caused massive wave swells to inundate the pier and harbor channel, compromising the wall. These waves are what likely caused the wall to move 3-5 inches, damaging the new boardwalk, O'Bryan said.
A summer fund raising effort raised more than $200,000 for the new wooden boardwalk project, which was completed by 20 volunteer builders for a little more than one week. An endowment was also created with the Grand Haven Area Community Foundation for future repairs to the boardwalk.
According to corps engineers, this latest development is the "better-case" scenario, as the worst-case scenario would be the whole bulb breaking loose from the ground.
O'Bryan said a repair of this magnitude would be both more extensive and expensive.
Now that officials have identified the nature of the harbor wall damage, work is now going to be done to try and mend the problem.
He said this will involve designers proposing a fix for the problem, and then submitting that design for project funding.
"It can be anywhere between $1 million to $5 million," O'Bryan said of the estimated cost to repair the wall so future damage is mitigated.
Those from the U.S. Army Corps of Engineers aren't unfamiliar with this type of problem occurring to harbor channel walls. Similar problems have occurred to a wall in South Haven.
While work is done to design a fix for the wall and it is submitted for funding, a temporary fix will likely be introduced that will include placing loose stone in front of the wall.
O'Bryan said this will shore up the problem and prevent the wall from moving any further and is similar to a fix they made in South Haven when a similar problem occurred.
