Hydrological process representation at the meso-scale: the potential of a distributed, conceptual catchment model

In order to achieve a process-oriented simulation of hydrological processes in a meso-scale basin (101–103 km2), the spatially and temporally variable basin inputs (precipitation and energy) and runoff generation processes need to be adequately addressed by the model. The catchment model TACD (tracer aided catchment model, distributed) is based on experimental results including tracer studies at the mountainous Brugga basin (40 km2). This raster-based model (50×50 m2) works on an hourly basis, thus capturing the spatially and temporally variable inputs and processes. The model contains a process-realistic description of the runoff generation mechanism, which is based on a spatial delineation of eight units with the same dominating runoff generation processes. This defines the model structure and enables efficient model parameterisation. The model uses linear and non-linear reservoir routines to conceptualise runoff generation processes, and includes a routing routine (kinematic wave approach) to simulate surface runoff.