Climate Variability and Change—Hydrological Impacts (Proceedings of the Fifth FRIEND World Conference held at Havana, Cuba, November 2006), IAHS Publ. 308, 2006, 454–459.

 

Regionalization of a distributed catchment model for highly glacierized Nepalese headwater catchments

 

Markus Konz, Ludwig N. Braun, Stefan Uhlenbrook, Siegfried Demuth & Arun Shrestha

 

1 University of Basel, Department of Environmental Sciences, Applied and Environmental Geology, Bernoullistr. 16, CH-4056 Basel, Switzerland

markus.konz@stud.unibas.ch

2 Bavarian Academy of Sciences, Commission of Glaciology, Alfons-Goppel-Str. 11, D-80539 Munich, Germany

3 UNESCO-IHE, PO Box 3015, 2601 DA Delft, The Netherlands

4 IHP/HWRP Secretariat, Federal Institute of Hydrology, Am Mainzer Tor 1, D-56068 Koblenz, Germany

5      Department of Hydrology and Meteorology, Snow and Glacier Hydrology Unit, Babar Mahal, PO Box 406, Kathmandu, Nepal

 

Abstract In this study, the distributed catchment model TACD was developed further and applied to three highly glacierized Himalayan catchments (141–360 km2). Snow and ice melt is regionalized using the calculated potential sunshine duration of each 200 ´ 200 m2 raster cell. Hydrological response units (glacier covered areas, non-glacier areas, flat glacier parts, valley bottoms) are simulated with different reservoir concepts. The model runs on a daily time step with daily mean air temperature and daily sums of precipitation as input data. It was calibrated successfully for the Langtang Khola catchment, Nepal, and this parameter set formed the starting point for the application of the model to the Modi Khola and Imja Khola catchments. In the case of the Modi Khola catchment the parameter set was left unchanged and used directly for discharge simulation, and only minor modifications of the parameter values of the snow and glacier routine were necessary for the Imja Khola catchment to obtain reasonable runoff simulations. It was demonstrated that this distributed modelling approach enables the assessment of the temporal and spatial distribution of runoff from high mountain areas where data are limited.

 

Key words TACD model; regionalization; Himalayan headwater; Nepal; distributed modelling; process-oriented runoff simulation; Langtang; Annapurna; Khumbu