Natural river channels continually evolve and change shape over time. As a result, channel evolution or migration can cause problems for bridge structures that are fixed in the flood plain. A once-stable bridge structure that was uninfluenced by a rivers shape could be encroached upon by a migrating river channel. The potential effect of the actively meandering Wabash River on the Interstate 64 (I64) Bridge at the border with Indiana near Grayville, Illinois, was studied using a river migration model called RVR Meander (RVR Meander, 2011). RVR Meander is a toolbox that can be used to model river channel meander migration with physically based bank erosion methods. This study assesses the Wabash River meandering processes through predictive modeling of natural meandering over the next 100 years, climate change effects through increased river flows, and bank protection measures near the I64 Bridge.
The calibrated model was used to run three scenarios. The first scenario investigated the natural meandering of the Wabash River over the next 100 years (20132113). The second scenario predicted potential climate change effects on the meander migration of the Wabash River by increasing the model bankfull flow by 10 percent. The third scenario investigated how proposed bank armoring on the right bank of the Wabash River just north of the I64 Bridge would influence the meandering pattern. Model outputs include one-dimensional shapefiles of the migrated centerlines at defined increments.
RVR Meander, 2011, River meander migration software, accessed June 2016 at http://www.rvrmeander.org/software.html.