Die Bodenkultur - Journal for Land Management, Food and Environment

H. Holzmann and C. Massmann:

Development and test of a modular hydrological model concept with different degrees of complexity


Many hydrological models have been developed in the past two decades. Most of them used a fixed design to describe the variable hydrological processes assuming to be representative for the whole range of spatial and temporal scales. This assumption is questionable as reported by McDonell et al. (2007). But it was also evident that model application and the interpretation of results are limited by data availability to identify the particular sub-processes, since most models were calibrated and validated only with discharge data. Therefore it can be hypothesized that simpler model designs, focusing only on the dominant processes, can achieve comparable results with the benefit of fewer parameters. In the context of a research project a modular model concept was developed that allows the integration and neglection of hydrological sub-processes depending on the catchment characteristics and data availability. In this paper a comparison between a conventional HBV-type hydrological model and a modular concept with (1) simple and (2) complex process representation will be discussed. It could be shown that a flexible model design – and even the simple concept – can reach equivalent performance compared to the conventional model type. The main benefit is the individual adaptation of the model structure with respect to data and process availability and the option for parsimonious model design. Key words: Modular model, hydrological modeling, flexible model design, dominant processes.