Modified level II streambed-scour analysis for structure I-69-87-4781 crossing Wabash River in Huntington County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sediment transport data are evaluated to calculate the depth of scour that may result when a given discharge is routed through a bridge opening. The results of the modified Level II analysis for structure 1-69-87-4781 on Interstate 69 crossing Wabash River in Huntington County, Indiana, are presented. The site is near the town of Markle in the eastern part of Huntington County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 13.1 feet for the modeled discharge of 10,600 cubic feet per second and approximately 14.6 feet for the modeled discharge of 17,000 cubic feet per second.