Estimation of runoff for proposed hydropower stations near Jakobshavn and Christianshåb, West Greenland

Abstract

During the winter of 1983-1984 the authors worked together with T. Thomsen and G.H. Jørgensen, Greenland Technical Organization (GTO), to make estimates of runoff conditions for proposed hydropower stations near Jakobshavn (at Pâkitsup akuliaruserssua) and near Christianshåb (at Kugssup tasia) (fig. 38). This co-operation was necessary because neither GGU nor GTO had sufficient information to do the job alone. For example, the streamflow in both areas is dominated by runoff from the Inland Ice, and we provided the delineations of the glacier-covered areas (Thomsen, 1984) and estimates of various glacier climate parameters (Braithwaite, 1984a), together with one year of mass balance data from the area (Thomsen, 1984). an the other hand, GTO had measured the runoff in both areas for the four years 1980-1983 and we benefitted by access to this data. Both groups used climatological data from Jakobshavn, provided by the Danish Meteorological Institute, as a basis for the hydrological calculations. Bach group used their own model, i.e. the MB1/SM1/ RO1 models from GGU (Braithwaite, 1984b) and a modified NAM-I1 model from GTO (Thomsen & Jørgensen, 1984), and made separate calculations. A summary of the results was sent to the engineering companies responsibIe for preparing designs of the two hydropower stations. Detailed descriptions of our methods and results are given in Braithwaite & Thomsen (1984a,b) and will only be summarized briefly here, especially to illustrate points of principle.