The effects of discharge and slope on hyporheic flow in step‐pool morphologies

• DOI: 10.1002/hyp.10155
• Publication Date: 2014-01-16T20:30:51Z
• Authors: Marwan A. Hassan; Daniele Tonina; Roger D. Beckie; Matthew Kinnear
• Keywords: Downwelling; Hyporheic Zone; Flume; Riffle

Abstract This paper focuses on surface–subsurface water exchange in a steep coarse‐bedded stream with step‐pool morphology. We use both flume experiments and numerical modelling to investigate the influence of discharge, channel slope sediment hydraulic conductivity hyporheic exchange. The model reach, whose topography is scaled from natural river, consists three units 0.1‐m step heights, discharges ranging between base over‐bankfull flows (scaled values 0.3–4.5 l/s) slopes 4% 8%. Results indicate that deepest flow occurs steeper at moderate downwelling fluxes steps are highest largest discharges. In contrast findings pool‐riffle morphology, those this study show cause deeper exchanges than gentle slopes. Numerical simulation results portion zone influenced by surface temperature increases conductivity. These simulations emphasize importance topography, permeability roughness elements along governing locations magnitude Our zones these streams thicker previously expected extending bed forms. Copyright © 2014 John Wiley & Sons, Ltd.