July 25, 2011
07/26/11 The Marshall County Drainage Board held a special meeting Monday to discuss the bank erosion issue of the Yellow River in downtown Plymouth.
R.W. Armstrong was hired by the county to find ways to stabilize the ditch bank on the east side of the river near the footbridge. The representative explained three alternatives ranging in cost estimates from $189,000 up to $230,000.
All three proposals included the placement of A-jacks for stream-bank protection for 2,400 feet. The A-jacks are made of concrete and look similar to the pieces of the old fashioned game of jacks. They are relatively easy to design, install. It was noted that they can be stacked by hand which reduces the overall cost.
The fix for the upper bank stabilization has three options with the first and cheapest being to purchase the home on the south east corner of the walking bridge and then demolish the residence and create a new easy slope to the river’s edge using an erosion control blanket and plantings for stabilization.
Both of the other options require would require the construction company place a barge in the Yellow River and work from the barge. Alternate 2 includes encapsulated soil lifts with a total project estimated at $320,000.
Alternate 3 includes soil backfill with an articulated concrete mat over the slope. The estimated cost of this project is $264,000.
Representatives from R.W. Armstrong said, “There is further instability of the upper bank. The home has a deck on the west side that is only 10 to 12 feet signs of instability in the yard.” He said, “Will If you don’t do anything this is going to continue. Another large flood event will further degrade the stability of the bank.”
County Surveyor Larry Fisher noted, “In the last 15 years there has been a loss of a huge tree and we have had continuing erosion since then.”
The County Attorney will review the property acquisition process to determine if the Drainage Board has the power to purchase or if the Commissioners would need to. He will report to the Drainage Board at their August meeting.