The Miami Conservancy District (MCD) is currently seeking bids for concrete work on the Germantown Dam auxiliary spillway, a project they previously said would cost $1.9 million.
The bids for concrete work are due April 14, and the MCD is projecting the work will happen this summer, ending around October.
According to the notice published by the Miami Conservancy District, the work includes “mobilization, demolition of existing concrete grade control weirs, construction of new concrete revetment (side slopes), construction of new grade control weirs, installation of underdrain, restoration of the site, and demobilization.”
The spillway is a mowed area next to the dam, with visible concrete sides. The purpose of the spillway is to act as a release in the unlikely event that the storage capacity of the dam would ever be exceeded.
In a statement, the Miami Conservancy District noted that the emergency spillway at Germantown Dam has never been needed since the system was completed. “That’s by design—our dams are engineered with multiple layers of protection, and the spillway is there as an extra safeguard for extremely rare, worst-case scenarios. It’s one more way we make sure communities stay protected.”
According to data from the MCD, the highest “storage event” at the Germantown Dam was in January 1959, when the dam was at 31.8% of its storage capacity. Most recently, in 2005, the dam reached 19.8%, making that the fourth highest water event in the dam’s history.
📸 Google Maps
The above view from Google Maps shows the spillway north of the dam, reconnecting to Twin Creek on Old Mill Road.
The spillway at the Germantown Dam is different than others in the Miami Conservancy District. You can see in the photo below of Huffman Dam, that the spillway there is an area where water can safely go over the dam—and under the road.
📸 Miami Conservancy District
About the Germantown Dam
Construction can only happen during periods of low and stable water levels because the dam must remain ready to store floodwaters at all times.
The Germantown Dam spans 1,210 feet across Twin Creek. Constructed in 1920, it’s capable of storing up to 34.55 billion gallons of floodwater and managing it through two massive conduits — each 546 feet long, 9.1 feet high, and 13 feet wide — that run through the bottom of the dam.
The Germantown Dam was constructed 1918-1920 following the founding of the Miami Conservancy District after the 1913 flood that affected Dayton, Germantown and multiple cities.
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