As it happens, the Minnesota River flowed along the northern section of the river valley in this area. When the dam was built in the early 1970s, it crossed the entire river valley. It blocked not only the the Minnesota River, but several other small rivers and streams as well. One of these rivers is the Yellow River. It once flowed under US-75 and converged with the Minnesota River about a half-mile east of US-75. This bridge was built over that river channel. When the dam was built, the bridge was reused for the outflow channel of the dam. During periods of high water, the outflow channel carries the water from all of these rivers and streams, which results in high water flows in the outflow channel. These high flows come very close to the bottom of this bridge, as seen in the photos below. The last photo at the bottom shows a more typical water level during a period of normal water flows.
The bridge itself is typical of a 1950's era highway bride. It uses steel girders and a concrete deck, plus metal guardrails. A more modern bridge would use concrete girders because steel requires maintenance and painting. Also, a more modern bridge would use slanted concrete guardrails to help lessen the impact of crashes and to keep road debris from getting into the river.
