STEPS Seminar Series: “Bankfull Discharge and Bankfull Channel Characteristics of Alluvial Rivers: Can We Get Beyond the 1.5 Year Flood?”, Dr. Gary Parker , from the University of Illinois At Urbana-Champaign | Civil and Environmental Engineering

Friday, March 22 at 3:10pm

STEPS Building, 101
1 W Packer Ave, Bethlehem, PA 18015


It has long been known that alluvial rivers are the authors of their own geometry. In principle, water in the form of rainfall, a supply of sediment and vegetation should be sufficient ingredients for a channel to form on an initially featureless floodplain, and to acquire the standard features of hydraulic geometry. Available today are a wide range of empirical and theoretical techniques to estimate bankfull width, bankfull depth and slope as functions of bankfull discharge and parameters related to sediment. Yet bankfull discharge itself should not be a dependent variable. Rivers ought to choose their own bankfull discharge in the process of making their channels. Bankfull discharge has been empirically related to a flood recurrence interval such as the 1.5 year flood. While such specifications are useful, they shed no light on the processes giving rise to bankfull characteristics. Here we investigate the morphodynamics of the problem in terms of floodplain building and floodplain lowering processes, as well as channel aggradation and degradation. The morphology we consider is a single-channel meandering river. The river is subjected to a flow duration curve, characterizing the probability of exceedance of any given discharge. Relatively low flood flows encourage the removal of sediment from the floodplain as the channel migrates, rendering the channel shallower. Relatively high flood flows, on the other hand, deepen the channel through overbank deposition. Integrating over the flow duration curve allows determination of bankfull discharge itself, along with bankfull channel characteristics. Applications are presented for the Trinity River, Texas and the Minnesota River, Minnesota.



Professor Gary Parker received a B.S. from the Department of Mechanics and Materials Science of Johns Hopkins University (1971) and a Ph.D. from the Department of Civil Engineering of the University of Minnesota (1974). Before coming to the University of Illinois, he was an Institute of Technology Distinguished Professor in the Department of Civil Engineering at the University of Minnesota. One of Professor Parker's major research goals is to use the fundamental techniques of fluid mechanics and applied mathematics to treat interesting geomorphological problems. Professor Parker was elected to the National Academy of Sciences (NAS) in 2017. He also has received numerous other honors over the years, including the Hunter Rouse Hydraulic Engineering Award, the Water Resources Research Editor’s Choice Award, the American Geophysical Union G. K. Gilbert Award, the BSG Wiley Blackwell Award, Einstein Award, Hilgard Prize and Stevens Award from the American Society of Civil Engineers, the G.K. Warren Award in Fluviatile Geomorphology, and the Schoemaker Award twice and the Ippen Award from the International Association of Hydraulic Research.


Coffee and cookies will be served at 2:55p.m.