1st International Congress on Environmental Modelling and Software - Lugano, Switzerland - June 2002
Keywords
hydrotopes, alpine catchment, topographic effects, prms
Start Date
1-7-2002 12:00 AM
Abstract
An application of the Precipitation Runoff Modelling System (PRMS) based on the concept ofHydrological Response Units (HRUs) is presented for hydrological modelling of an alpine catchment. This isthe Aare River catchment upstream of the Lake Thun, in the Bernese Oberland Region, Switzerland, which ischaracterised by large glacierised areas. Accounting for these areas required to develop further the originalPRMS, which was rarely used in alpine regions. Particular attention was devoted to the analysis of the temporaland spatial distribution of temperature and rainfall within the catchment. The derivation of distributedmodel’s parameters was based on an extensive database of catchment characteristics available for the region,thereby including a 25 m resolution Digital Elevation Model (DEM), and digital maps of geotechnical properties,soil and landuse. The encouraging results in spite of the highly complex catchment morphology underlinethe importance of the availability of spatially distributed data to be used for HRUs identification andparameterisation. Such availability allowed transferring the parameter set from one subcatchment to anotherwithout significant loss of model efficiency. However, as expected, the model was strongly sensitive to theparameters describing the runoff generation processes (retention capacity of the unsaturated storage, snowmeltinfiltration capacity) and the routing of water in subsurface and groundwater reservoirs. This is due tothe intrinsic variability of these parameters, but may be enhanced by the general lack of specific distributeddata that could be used to improve calibration. Accordingly, the study concludes about the evident need forenlarging data availability in relation to subsurface and groundwater processes, or, alternatively, in fosteringthe development of robust parameter calibration methods, which rely on data that are generally available.
Hydrotope-based river flow simulation in a Swiss Alpine Catchment accounting for Topographic, Micro-climatic and Landuse Controls
An application of the Precipitation Runoff Modelling System (PRMS) based on the concept ofHydrological Response Units (HRUs) is presented for hydrological modelling of an alpine catchment. This isthe Aare River catchment upstream of the Lake Thun, in the Bernese Oberland Region, Switzerland, which ischaracterised by large glacierised areas. Accounting for these areas required to develop further the originalPRMS, which was rarely used in alpine regions. Particular attention was devoted to the analysis of the temporaland spatial distribution of temperature and rainfall within the catchment. The derivation of distributedmodel’s parameters was based on an extensive database of catchment characteristics available for the region,thereby including a 25 m resolution Digital Elevation Model (DEM), and digital maps of geotechnical properties,soil and landuse. The encouraging results in spite of the highly complex catchment morphology underlinethe importance of the availability of spatially distributed data to be used for HRUs identification andparameterisation. Such availability allowed transferring the parameter set from one subcatchment to anotherwithout significant loss of model efficiency. However, as expected, the model was strongly sensitive to theparameters describing the runoff generation processes (retention capacity of the unsaturated storage, snowmeltinfiltration capacity) and the routing of water in subsurface and groundwater reservoirs. This is due tothe intrinsic variability of these parameters, but may be enhanced by the general lack of specific distributeddata that could be used to improve calibration. Accordingly, the study concludes about the evident need forenlarging data availability in relation to subsurface and groundwater processes, or, alternatively, in fosteringthe development of robust parameter calibration methods, which rely on data that are generally available.
