U.S. highway 83 is part of a bypass to the west of Minot, N.D. Just upstream along the flooding Souris River, the 83 Bypass bridge was the only north / south link for residents of Minot for many days during this record flooding. As the water recedes, down six feet in the last 10 days, other bridges have reopened.
During the flooding, North Dakota Department of Transportation engineers have used boats provided by the Fish & Game Service to monitor the Souris River channel. The channel’s width and depth is known, and, by using a depth finder, the engineers can determine if the flooding has caused any changes.
On July 6, the findings were normal. By July 8, changes were discovered near the south bank of the Souris where the bridge abutment is sited. The area was reinforced with heavy stones, called rip rap. The Monday inspection revealed that the southernmost pier of the bridge had also been endangered by the scouring from the flood that was making changes in the river channel. The bridge was immediately closed, according to Minot Daily News.
I spoke Wednesday with Terry Udland, the state bridge engineer from the North Dakota DOT, about the situation. The immediate danger to the bridge is from settling, as the scouring could undermine the structures and cause the abutment and the pier to sink. The bridge was built in 1976 and is a concrete structure.
The NDDOT is examining all the options. Udland hopes that a plan will be formulated in about a week. The bridge will remain closed until its safety can be assured. There are 10 bridges in the Minot area over the Souris. Some are state bridges, such as the 83 Bypass, while others belong to the City of Minot. Udland told me that each bridge is thoroughly inspected before it is reopened. His agency is working with the city to inspect bridges. Along the length of the Souris in the United States, there are 23 state and local bridges.
Much of Minot remains underwater. The Souris River flooding has dropped below the level of the original levees. Some areas in the evacuation zone have been opened to residents during daylight so the process of inspection and recovery can begin.
Due to the flooding, and especially the flooding of the fair grounds, the North Dakota State Fair has been canceled. It was scheduled to take place July 22-30.
The “boil water” order has been lifted for parts of the city as the Water Department has been able to flush the system in some areas and ensure that only treated water is in the pipes. The need to conserve water within the Minot municipal water system still remains critical.