Interaction of Tide and River Flow

Abstract

Studies on the interaction of tide and river flow are scarce, while studies on the simplified characteristics of tides in canals and gulfs are common. This study employs the perturbation method to solve analytically the interaction of tides and river flow, taking into account the nonlinear convective inertia and bottom friction. Appropriate characteristics of the interaction obtained from an analysis of five records along a river are used in the derivation and verification. The study finds that the interaction of the tide and the river flow is well‐described by the analytical solution for implicit doppler shift. Exclusion of convective term yields an underestimation of the tidal damping. The river flow raises the mean water level but damps the tide and reduces its celerity. The raising of the mean water level during a high discharge is more than the damping of the tide, causing flooding at high water level. Application of the analytical solutions for any value of the river flow requires only the bottom condition of the river, which is found to be smooth for the large alluvial river.