Modified level II streambed-scour analysis for structure I-70-35-5245 crossing Big Walnut Creek in Putnam County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sedimenttransport 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 1-70-35-5245 on Interstate 70 crossing Big Walnut Creek in Pumam.County, Indiana, are presented. The site is near the town of Manhattan in the southwestern part of Putnam 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 17.0 feet for the modeled discharge of 29,200 cubic feet per second and approximately 30.9 feet for the modeled discharge of 49,600 cubic feet per second.