MODELING THE STREAM-AQUIFEER INTERACTION DURING FLOOD AND EVALUATING THE FLOOD FLOW REDUCTION THROUGH RIVERBANK SEEPAGE STORAGE

Abstract

 A key to achieving "basin flood control" is to restore and utilize the infiltration and storage functions of rivers and basins. In this study, by taking advantage of the riverbank seepage storage phenomenon inherent in rivers, the possibility of reducing flood flow by temporarily storing flood flow on the riverbank was investigated. Based on the governing equations of stream flow and groundwater flow, the interaction in coupled system of the river channel and the riparian permeable layer was modeled. A wide range of permeability from fine sand to gravel was set respectively for the case where the riparian permeable layer spreads semi-infinitely from the river channel and the case where its spread is limited to a finite range. By flood routing with the interaction between stream and groundwater, the extent to which the presence of the riparian permeable layer can contribute to reducing flood flow was quantitatively evaluated. The results showed that if the ground in the riverside area is sandy and gravelly, it is possible to sufficiently reduce flood flow through riverside infiltration storage.