The South Dakota Department of Transportation said this week that its corridor study related to the replacement of the Platte-Winner Bridge on State Highway 44 is now complete.
The study is the documentation of how the DOT has determined its preferred alternative for replacing the bridge. In 2018, the DOT favored a new bridge to the north of the current structure built in 1965, and study documents show it will be skewed in a way that will make it non-parallel to the current bridge. Officials say it will minimize impacting cultural and natural resources, help keep the existing bridge open during construction and minimize the impact to the Snake Creek Recreation Area.
The next step, according to a news release, is for the the development of an environmental assessment, which the DOT expects to publish later in 2020 after agreements are finalized for mitigation of impacts with the South Dakota Department of Game, Fish and Parks, the U.S. Army Corps of Engineers and the State Historic Preservation Office. Another set of public meetings will be held during the environmental assessment period, officials said.
The DOT says proposed north alignment would result in the highway and the bridge being elevated by about 10 feet from the current elevation on the bridge, resulting in taller bridge piers and a slightly higher cost. An estimated cost for the entire project has not been determined.
Bridge construction is currently estimated to take place around 2025, with the goal of building bridge with a 100-year design life. The current bridge, also known as the Francis Case Memorial Bridge, is located 14 miles west of Platte and nearly 40 miles east of Winner and is the state's longest bridge at 5,655 feet to span the Missouri River.