Joint meeting July 18 will discuss ways to upgrade west abutment of Bridge St. structure, dredge impoundment
Village of Grafton officials will begin next week to discuss options for upgrading the Bridge Street dam to meet state requirements for flood control.
During a 6 p.m. joint meeting Monday, July 18, at Village Hall, members of the Village Board and Public Works Board will review a recently completed engineering study by Bonestroo outlining three main options for improving the damâ€™s west abutment.
The options include:
â€˘ Replacing the masonry wall with a concrete wall, reconfiguring the public overlook and raising the river walk, estimated to cost $170,000 to $205,000.
â€˘ Installing gates to provide flood control and allow dewatering of the dam reservoir, estimated to cost $550,000 to $1.6 million.
â€˘ Enlarging the dam weir to provide flood control and create additional recreational activities such as canoeing and kayaking. Estimated costs range from $1 million for a 150-foot weir to more than $2 million for a 1,000-foot weir.
In a report to the boards, Village Engineer Dave Murphy states each option would bring the dam into compliance with state statute NR 333, which regulates dam safety, including flood control. The state Department of Natural Resources has required
the village to comply with the law by 2019.
In lieu of razing the dam, that requirement must be met because voters passed a binding referendum in April 2010 to preserve the landmark until at least 2019.
The village must pay for east-abutment upgrades. That cost is expected to be covered using revenue from the downtown tax incremental financing district, which voters supported in an advisory referendum.
Upgrades to the east abutment are included in a proposed fish passage Ozaukee County plans to build using federal funds. However, the future of that project is in doubt since the DNR announced that it intends to deny a permit request due to
concerns about the spread of invasive species.
A final DNR decision on the request is expected by July 18. If the fish passage is not built, the village is also expected to have to pay for the west-abutment improvements, which Murphy said would cost $100,000.
Also on Monday, the boards will discuss options for dredging sediment from the dam reservoir, which Murphy said would â€ścreate a more scenic impoundment and allow more recreational activities in this area.â€ť
Depending on the areas dredged and the amount of sediment removed, the process would cost $250,00 to $895,000, Murphy said. The cost could be reduced if a gate is installed as part of west-abutment upgrades, he added.
Village Administrator Darrell Hofland said the boards are expected to provide input on the east-abutment and dredging projects so Murphy can make recommendations to the Public Works Board at its Aug. 8 meeting.