Irek Sobota
Department of Cryology and Polar Research,
Institute of Geography,
Nicolas Copernicus University,
Fredry 6/8, 97-100 Toruń, POLAND,

Irek Sobota

Preliminary characteristics of run-off from Waldemar Glacier (Kaffioyra, NW Spistbergen)in the 1996 summer

The Waldemar Glacier whose waters flow into the Waldemar River, is a glacier of the Alpine type of an area of about 2.66 km2 (Lankauf - oral information). The Waldemar River basin occupies an area of 16.5 km2. The position of the glacier front significantly affects the regime of glacier rivers. The Waldemar Glacier has recently been characterized by a great rata of recession with a land loss of over 1% a year (Lankauf, 1989, 1993, 1995).
The mean outflow from the glacier and the Waldemar River basin, the intensity of flow and its relation to the glacier ablation intensity in the period of 20 July - 13 August, 1996 have all been assessed. Some physicochemical properties of the waters carried by the river were studied. The glacier barrier lake in the Waldemar Glacier was also examined.
It was found that the greater intensity of flow (Tab.1) in the upper part (below the ravine) is due to the location of the river flow, this being its effluence onto the glacier forefield. The waters flow directly from the glacier. There is an evident relation between the ablation size and the flow intensity. More uniform intensity of the flow in the middle part of the river is connected with the different path of the river feed compared to that in the upper part. Apart from the waters flowing down from the glacier (ablation), the waters from permafrost thawing, as well as those from small lake synclines together with those flowing from the neighbouring glaciers - all play a significant role. The greatest variability of water levels was observed in the rivers mouth region which is connected to the tidal effect of the sea.
The mean outflow in the studied period was 96612.0 m3/24h in the upper part and 119243.3 m3/24h in the central part. Assuming that below the ravine the waters come directly from the glacier ablation, it was found that 81% of 1907988.8 m3 water outflowing the Waldemar River came from the glacier ablation. The size of outflow from the glacier basin in the summer period is a function of glacier ablation and then of local sources of flow supply (among others pronival waters, rainfalls, waters from permafrost thawing). The size of glacier river outflow in the summer can be written in the form of the function:

OL = j(A + Z)
where: OL - the glacier river outflow, A - ablation supply,
Z - local sources of supply

The temperature of the Waldemar River water increases with its flow and its decrease is periodically observed at the estuary,this is due to the tides. The amount of suspension transported by the Waldemar River decreases when it gets closer to the river mouth resulting in the deposition and building of the sandur plain. The general mineralization of the water is inversely proportional to the ablation size. The decrease in conductivity is evidence for the significant participation of ablation waters in the outflow, this has been confirmed by other authors (among others Krawczyk et al., 1990; Jania, 1993).
The formation of the glacier barrier lake has been observed on Waldemar Glacier since 1995. The lake occupies an area of about 0.5 ha. It was formed due to the outflow blockade by the central moraine ridge in the western part of the glacier.
The intensity of the main flow supplying the lake was directly proportional to the glacier ablation. With the increase of glacier melting, the supply of water in the lake increases. At the same time, the increased outflow from the reservoir causes a greater outflow of the glacier river. In the study period, 239760.0 m3 water flowed out of the lake. At the same time, the outflow in the upper part of Waldemar River was 1159355 m3. This means that the outflow from the glacier lake was 20.7% outflow from Waldemar Glacier. The remaining 79.3% came directly from the glacier ablation. This ratio shows the role of the barrier lake in the total outflow from the glacier and in supplying the Waldemar River.
In summer the outflow from the glacier and glacier river basin depends mainly on the size of glacier ablation ,other local sources are of secondary importance . The fact that the 1996 summer was short and cold with and very wet, had a significant influence on the outflow from Waldemar Glacier.

Table 1. Parameters characterizing intensity of flow and outflow of the Waldemar Glacier River (NW Spitsbergen)
Middle partVmean m/s1,071,081,071,041,15-1,08-
Vmax. m/s1,161,681,251,231,37-1,34-
Q m3/s1,3540,9511,2451,2592,092-1,380-
Outflow m3/24h116985,682166,4107568108777,6180748,8-119249,31907988,8
Upper partVmean m/s1,7-0,71,081,680,951,22-
Vmax. m/s1,92-0,921,391,951,251,49-
Q m3/s1,736-0,1410,3662,6780,6701,124-
Q %*128,2-11,329,1128,0-74,2-
Outflow m3/24 h149990,4-12182,431622,4231379,25788896612,981545087,7
Outlow %*128,2-11,329,1128,0-74,2-
Remaining flowsOutflow m3/24h-33004,8-95385,677155,2-50630,4---
* - the percentage share of flow intensity and outflow size in relation to their value in the middle part of the river.
** - the average total outflow size (m3) in the period 29 July.-13.August 1996.


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