Simulating low streamflows with hillslope storage models

In this study a deterministic approach is applied to estimate low-streamflow series and statistics at a watershed scale. The kinematic wave hillslope storage (kw) and the hillslope storage Boussinesq (hsB) models are applied in conjunction with a simple conceptual framework to a small steep headwater catchment that is part of the Maimai watersheds in New Zealand. The models are compared on the basis of their ability to reproduce base flow series and low-streamflow statistics. Variations in the number of hillslope partitions and the impact of homogeneous and variable model parameters across hillslopes are explored. Our results confirm findings from previous studies that have indicated that for steep hillslopes like those at Maimai the kw and hsB models produce similar results. More partitioning and variable parameters across the watershed can better capture hydrogeologic heterogeneity, resulting in improved model performance.