Hillslopes are the basic elements of many landscapes. The study of hillslope processes forms a central theme in many earth sciences, such as geomorphology, physical geography and hydrology, as well as the applied sciences, such as civil and agricultural engineering. Understanding the interaction and feedbacks between hillslope forms and the flow processes responsible for transportation of water, sediments and pollutants is of crucial importance for catchment scale water and land management. Models that are traditionally used to describe these hillslope hydrologic processes are generally very computationally demanding and are difficult to parameterize. Aim: the main objective is to further develop and thoroughly test a newly introduced theory of storage-based hillslope dynamics, based on the Boussinesq equation, and generate a new type of computational efficient semi-distributed hydrological model that can be used in practice on the catchment scale. Hypothesis is that a low dimensional dynamic model, based on the Boussinesq equation, can capture the essential physical behavior of a natural system on hillslope- and catchment scale. By applying this low-dimensional type of model on catchment scale we will investigate runoff processes in catchments. With this information we will investigate the dominant factors influencing flooding events within a catchment, especially for wet conditions (e.g. through variable source area analysis).