HUMAN INFLUENCES ON FLUVIAL GEOMORPHIC PROCESSES IN A CHANNELIZED, AGRICULTURAL FLOODPLAIN ALONG THE EAST FORK WHITE RIVER, INDIANA (Invited Presentation)

An interconnected network of channels persists on the floodplain of the single-thread, meandering East Fork White River in Indiana. These channels have been recently identified in high resolution topographic data and upon further analysis have been found to actively convey flow below bankfull stage. Many purely hydrogeomorphic questions remain as to the pervasiveness, function, and evolution of these channels. However, this floodplain, including many of its floodplain channels, is used for row crop corn and soybean agriculture despite the high frequency of inundation of the farmed floodplain channels. Several low-lying floodplain channels are grassed waterways, but these have a tendency to trap fine sediment and widen, thereby further reducing the amount of useful arable land. Land cover decisions of farmers on whether to plant crops or grass in these floodplain channels has a direct influence on the future evolution of this floodplain. In this presentation, we will discuss the coupled human-geomorphic processes at work in this system. Furthermore, we will present preliminary 2-dimensional hydraulic modeling and sediment analysis results aimed at understanding the underlying physical processes shaping this channelized, agricultural floodplain.