Glaciers and hydropower for Nuuk/Godthåb, West Greenland

Investigations have been made by the Greenland Technical Organization since the early 1980s on the feasibility of hydropower for Nuuk/Godthåb, West Greenland. The main source of water would be the Kangerluarsunnguaq (KNNQ) basin to the south of Nuuk although the possibility of transferring extra water from another basin, the Isortuarsuup Tasia basin (ISTA), was considered at an early stage of planning. The KNNQ basin contains only a sparse glacier cover while the ISTA basin has an extensive glacier cover, Including sectors of the Inland Ice, and contains large Ice-dammed lakes. Glaciologlcal measurements have been made by the Geological Survey of Greenland (GGU) at Qamanårssûp sermia to the north-east of the area, and In both the KNNQ and ISTA basins, and the present report assesses the possible effects of glaciers on runoff from both basins.

Runoff from the KNNQ basin is not significantly Influenced by glaciers and the basin Is essentially a precipitation basin. By contrast, glaciers are the main source of runoff from the ISTA basin and strongly influence
runoff variations through both ablation variations and the filling/draining of Ice-dammed lakes. Runoff simulations for the KNNQ basin by GTO can therefore ignore glacier effects but there is a serious problem with the homogenulty of the precipitation data from Nuuk which is caused by the relocation of the measuring station and must be solved. Runoff simulations for ISTA must Include glacier effects, and especially runoff from the Inland Ice.

GGUs measurements of accumulation on a glacier in the KNNQ basin can be used to forecast runoff from the basin, and should be continued, and possibly extended, as a contribution to the operation of the hydrapower station if it is ever built.