Lahmer, W., Becker, A., Müller-Wohlfeil, D.-I. and Pfützner, B. (1997). A GIS-based Approach for Regional Hydrological Modelling. Accepted for IAHS publication (International Conference on Regionalization in Hydrology, Braunschweig, March 1997).
The heterogeinity of landsurface properties represented in maps of different spatial resolution and discretization plays an important role in physically-based hydrological modelling. In order to use the basic information provided by these maps for the derivation of parameters used in hydrological models and to consider the importance of heterogeinity on the hydrological response of landscapes and regions, appropriate discretization schemes and modelling approaches are necessary.
- an open structure which allows the inclusion of other models or modules differing in spatial resolution and detail of process description.
The regionalization principles are based on the variable aggregation and disaggregation techniques for spatial data provided by GIS operations in the preprocessing stage. Thus, they are part of the modelling concept which allows hydrological simulation calculations on various aggregation levels (elementary units, hydrotope classes, subcatchments, and catchment).
The results obtained in the present study provide considerable new insight into the following questions of hydrological regionalization:
- Can the algorithms and methods used for high resolution data (small spatial scale) be transferred unchanged to larger scales, where low resolution data must be used?
- When and to what extend must a study region be disaggregated into spatial units representing differences in land use, land cover type, topography etc.?
- In what cases can subgrid heterogeneities be represented by effective parameters or statistical distribution functions?
- Which data (and how detailled) are necessary for a physically-based hydrological modelling approach at a specific scale?