Author(s): Robert Ettema; Christopher Thornton; Steve Abt; Caroline Ubing
Linked Author(s): Robert Ettema
Keywords: Hydraulic modeling; Braided channels; Hydraulic structures; Sediment transport
Abstract: Few hydraulic engineering projects have entailed the use of moveable-bed hydraulic modeling of hydraulic structures located in braided channels subject to unsteady conditions of flow and bed-sediment transport. Such modeling involves several challenging considerations. Braided channels characteristically are relatively wide and shallow, have relatively large bed-sediment loads, readily shift, and importantly are self-forming. They are shaped by the magnitude and frequency of their flows, the amount and properties of the sediment they transport, and the slope of the valley they drain. These characteristics of braided channels, together with simulating unsteady bed-sediment transport, pose substantial complications for designing and interpreting hydraulic models of channel-control structures intended to modify or constrain bed-sediment transport and channel morphology of braided channels. This article briefly describes the similitude and model-design considerations adopted for modeling a challenging and rather unique, mobile-bed hydraulic model. Tests with the model are underway at the time this article was written.