PLATTE - The official planning process for replacing the Platte-Winner bridge is in its third year, and a general location for the new structure is now in the works.

In December, the South Dakota Department of Transportation said it was making progress on a preferred alternative site for the State Highway 44 bridge, locating it north of the current structure, which was built in 1966 and last had major repairs in 1997. Among the state's major bridges, the Platte-Winner Bridge, or the Francis Case Memorial Bridge as it is also known, was deemed a top priority to be replaced in 2016 when the state did a study of its major bridges.

In 2017, the state DOT said the new bridge would be built within several hundred feet of the current structure, but no exact determination had been made regarding the bridge's location. During those meetings, members of the public also made it clear that it was important that the bridge was not closed or that traffic wasn't detoured, because a possible detour could require a trip of 70 to 80 miles.

Also among the priorities for 2019 is to complete the environmental assessment of the project. Public comment and additional meetings will be held regarding the potential replacement bridge later this spring. The environmental assessment will take into account feedback from other agencies, stakeholders, and the general public.

At the end of 2017, project leaders expected to have a preferred alternative decided by April 2018 and to complete its recommendations by July 2018, but the project schedule has slowed down into 2019.

The current timeline calls for the bridge - located about 15 miles west of Platte, and about 35 miles east of Winner - to be replaced in the mid-2020s. The 5,655-foot bridge is the longest bridge in the state, and cuts through the Snake Creek Recreation Area.

"One of the key advantages to this location is that the resulting new highway segment will avoid impacts to the state park campground at the Snake Creek Recreation Area," the state DOT said in an announcement. "SDDOT continues to work closely with South Dakota Game, Fish, and Parks (GF&P, owner and operator of the park) to determine appropriate measures to minimize and mitigate impacts to the park that will be caused by the project."

One of the other key factors is that the highway alignment has experienced numerous landslides, according to the state DOT, that have resulted in extensive repairs and expenses. A replacement is expected to be built to last 100-plus years.

Other initial findings in the study of the State Highway 44 corridor is that the current bridge has deep foundations in the river, down 200 feet to the river's bedrock. The current site of the bridge is also the most realistic spot for crossing the river, and repairs to the current bridge were not realistic.

A new bridge is expected to be wider than the current 28-foot wide roadway. In 2015, the bridge carried an average of 951 vehicles per day, with about 27 percent of those falling under a heavy vehicle classification. In 2035, the average daily traffic is projected at 1,298 vehicles per day, with a heavy vehicle percentage of almost 30 percent.