MKII Bridge Erection Boats position against the current Improved Ribbon Bridge (IRB) Bay Sections across the Arkansas River during River Assault 2017 on Fort Chaffee Manuever Training Center, July 26, 2017. The estimated 300-meter IRB across the river was the culminating event of River Assault. Operation River Assault, July 26, 2017. Operation River Assault is one of the key training events that demonstrates that America’s Army Reserve is the most capable, combat ready, and lethal Federal Reserve Force in the history of the nation. (U.S. Army Reserve Photo by Sgt. 1st Class Clinton Wood)