Studies of the Greenland Ice Sheet (GrIS) mass-balance have shown significant net losses and there seems to be a trend towards increasing losses, (e.g. Fettweis 2007, Hanna et al. 2008 and Mernild et al. 2008a). This has caused concern about both rising sea level and changes in the oceanic current circulation pattern. In spite of its importance very few measurements of runoff from the GrIS exists. Glacial erosion is one of the strongest erosive agents and sediment from GrIS is therefore distributed to fiords and oceans, where the result may be observed in bottom cores. However, again very few observations of actual transport to the ocean exists from the GrIS.

This investigation presents the first results from an IPY project aiming at an understanding of the hydrology and sediment transport forming the landscape at Kangerlussuaq. In 2007 a gauging station was established at the outlet of Watson River into the fiord at Kangerlussuaq. Some of the equipment was damaged during a jökulhlaup resulting in less information about discharge and sediment concentration. The station was rebuilt in 2008. Discharge is determined by multiplying the cross section area with velocity measured with the float method. A stage discharge relationship is established, R²= 0.68, expected accuracy is 10-15%. Max. velocities of 6-8 m s^-1 occur. The sediment concentration is found by collecting water samples manually and with an ISCO peristaltic pump sampler. A Partech Solitec 20 transmissometer is installed at the gauging station, the filtered water samples are used for calibration of the transmissometer, R² = 0.63. Sediment transport is calculated by using both a relationship between discharge and concentration and the sedigraph obtained with the transmissometer multiplied with the simultaneous discharge.

At the outlet the Watson River drains an area of app.6,280 km², hereof the GrIS is app. 90 %. However, the actual contributing area varies depending on climate and so far it is not known exactly. In spite of this the discharge and sediment transport is related to the area above as a first approximation. Discharge was 1800 10⁶ m³ in 2007 and 1300 10⁶ m³ in 2008 or respectively 286 and 207 mm from 6,280 km². The sediment transport (total load – because all bed load is brought into suspension at the cross section) was 3500 10³ t in 2007 and 2000 10³ t in 2008, equal to 560 t km² y^-1 and 320 t km² y^-1 in 2007 and 2008 respectively.

A jökulhlaup occurred the 31st August 2007, a new minor outburst occurred at the same date this year. Earlier observations indicate a return period of about 8 year, so the changing frequency of jökulhlaups may indicate a changing runoff regime, it is however too early to relate this to climate change.