Efects of hillslope geometry on soil moisture defcit and base fow using an excess saturation model

Estimation of watersheds base fow as a component of subsurface runof is of signifcant importance, in particular, in watersheds of high permeability where the contribution of base fow to total runof is large compared to that of surface fow. Complex hillslopes in nature have a diferent profle curvatures (concave, straight, and convex) and plan shapes (convergent, parallel, and divergent). In this study, an excess saturation model is developed to estimate the soil moisture defcit (SMD) profle along complex hillslopes. A new equation is presented which can predict base fow of hillslopes according to the spatially averaged SMD and topographic index over the hillslope surface. It is concluded that the hillslope geometry can obviously afect hillslope saturation and SMD. Moreover, the efect of convergence on SMD is higher than that of divergence. The largest and smallest efects on SMD are related to the convex convergent hillslope and the straight divergent one, respectively. Finally, the results of the developed model are compared to those derived from the solution of the hillslope-storage Boussinesq (HSB) equations for complex hillslopes.

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Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2021)