Background
Oslo, MN, is located approximately 19 miles north of Grand Forks, ND, along the Red River of the North in Marshall County. Oslo is protected by a levee system that was completed in 1981 and improved in 2012.
The transportation infrastructure in the area consists of local township roads, county roads, Minnesota Trunk Highway 1 (MN 1), North Dakota State Highway 54 (ND 54), I-29, and the Northern Plains Railroad (NPR). The ND 54/MN 1 highway bridge has been classified as structurally deficient and needs to be replaced or rehabilitated.
Oslo is located along the Red River in an area that is highly susceptible to spring and summer flooding. The 2009 historic event floodplain was approximately 8 miles wide near Oslo, inundating acreage in both Minnesota and North Dakota. During periods of high floodwaters, many roadways in the Oslo area are also inundated.
Inundation of these roadways puts a strain on the transportation infrastructure in the local community as well as the region, resulting in increased travel times, an inability to access Oslo, damage to the roadways, erosion to road embankments and farm fields, and agricultural crop damages or reduced yields due to delayed planting.
At the local scale, the community becomes stranded on an “island.” When this occurs, there is a concern over emergency vehicles being able to assist with emergencies that may occur within the city or surrounding areas. On a township/county scale, residents who live within the area but outside of the Red River floodplain are also impacted due to roadway detours when the bridges are closed. These closures can result in over 60 miles of detours. I-29 is a main thoroughfare for freight travel in the northern part of the state and internationally to Canada. The closure of I-29 results in detours to the freight transportation. This adds additional time and miles to these transporters and increases risk of damages to detoured State and County highways that are not designed for the increased freight loads.
Oslo experiences spring floods associated with snowmelt runoff along with summer floods associated with rainfall. USGS Streamgage 05083500 is located on the Red River near Oslo. The Oslo area has experienced destructive floods in recent years, including the spring floods of 1997, 2009, and 2011. According to stream gage data, floodwaters in Oslo have been above flood stage 28 of the last 51 years that flood stage data is available (1936-2017), and floodwaters have been above major flood stage 10 of the last 22 years (1996-2017).During flood events, the MN 317 roadway becomes overtopped, which causes the closure of the ND 17/MN 317 bridge. And although the bridge is closed, the ND 17 bridge approach would not be overtopped and has been identified as a potential flow restriction. Due to the overtopping of MN 317, the proposed modification to ND 17/MN 317 was to lower the bridge approaches to minimize the restriction of the natural floodwater flow path to the north.