Effect of Seepage on Alluvial Channel’s Morphology

The morphological behavior and stability of the channel are affected by seepage. The existence of seepage from (Suction) or into (injection) a channel alters the bed stability conditions, and consequently, the channel's hydrodynamic parameters change. (Lane. (1953). Critical tractive forces on channel side slopes (Issue 366). US Department of the Interior, Bureau of Reclamation, Design and ….) used analytical methods to obtain stable channel characteristics by solving the forces that might affect the sediment–water flow. Existing stable channel predictors, such as Lane's hypothesis, do not consider seepage as an independent parameter. According to Van (Leeden et al. in The Water Encyclopedia, Lewis Publication. Inc., Chelsea, MI, 1990), alluvial channel seepage losses are estimated to be between 15 and 45% of total input. Thus, studying and analyzing seepage processes in alluvial channels are essential. Experiments show that the channel with Lane’s geometric profile remains stable in case of no downward movement of water (without suction). Suction (seepage in the downward direction) weakens the stability of particles resting on the boundary and can cause them to initiate motion. The imminent movement of bed particles results in a new equilibrium state, entirely different from Lane’s geometric profile.