Transferable parameterization methods for distributed hydrological and agroecological catchment models

Summary The application of distributed hydrological and agroecological models requires the knowledge of model parameters, boundary conditions and initial conditions for each element of the three-dimensional finite difference grid in the catchment area under survey. This paper discusses methods suitable for processing the values of such parameters. The Digital Relief Model can be used to compute the ecologically relevant morphographic parameters for any point in the catchment, e.g. drainage direction, curvature, size of the drainage area above this point, distance from divide and drainage channel. The three-dimensional Digital Sediment and Soil Model determines the thickness of sediments and soil horizons as well as the parameters describing the sediments and soils (e.g. texture, structure, humus content) for any chosen site. The Land Use Data Processor computes data from maps, and remote sensing data (e.g. direction of tillage, height and density of plants) and makes these data available in any chosen grid. Only a limited number of measurements of the soil moisture suction, the soil moisture contents and the groundwater level will be necessary to derive a spatial distribution of these values on account of relatively close relations to relief and sediment parameters determined by the Digital Relief, and the Digital Sediment and Soil Models.