Following the partial failure and subsequent repair of Briggs Dam in 2017, the State of Michigan’s Dam Safety Division recommended the complete replacement of the spillway as a long-term solution.
The Village of Paw Paw has been working with a team from Barr Engineering in Minneapolis, Minnesota to design a new, modern spillway that would serve as a permanent water control structure where the Paw Paw River enters Maple Lake.
Earlier this year, Millbocker & Sons Construction from Allegan, Michigan was chosen as the company that will remove the existing spillway and construct the new one.
The new spillway will be a ‘labyrinth’ style weir. A ‘weir’ is the portion of a dam that is used to manage water levels and is designed to allow the river to flow over its crest. While known as Briggs Dam, the structure itself is technically a weir, in the sense that it is not designed to completely stop the flow of water but simply control its flow.
The capacity of a weir to flow water is determined by its length, height and shape. Rather than a straight, linear wall, a labyrinth weir is folded along its length like an accordion (see renderings), which greatly increases its length within the relatively narrow channel of the river, allowing for a higher flow rate during periods of heavier rain and higher water levels.
The new, higher-flow weir will have a small footprint within the space-constrained area yet meet modern standards for 200-year flood events, thereby relieving pressure on those elements of the existing dam and spillway remaining once the project is complete. In short, the new structure will be stronger and more efficient than the existing dam and spillway.
The project is expected to cost approximately $3 million, with approximately $2 million coming from State of Michigan legislative awards facilitated by Senator Aric Nesibitt.
After several years of planning, the project is beginning this week and is expected to continue through the end of the year.
The Village of Paw Paw understands that it is replacing an important local landmark. It is committed to the construction of a new Briggs Dam that will endure for generations and be an attractive, effective addition to the community.
