Ground Water Resources of British Columbia
Chapter 10 — Ground Water Resources of the Plateaus and Highlands Ground Water Regions
10.1.7 YUKON PLATEAU AND STIKINE PLATEAU
by
J.C. Foweraker
Yukon Plateau
In British Columbia the Yukon Plateau comprises parts of the Tagish Highland and the Teslin and Nisutlin Plateaus (Chapter 8, Figure 8.7). The Tagish Highland is a mountainous area in which there are numerous areas of gently sloping upland. The valleys are wide and U shaped and many to west of Atlin are occupied by lakes (Holland, 1964).
Figure 8.7 Ground water regions of the Plateaus and Highlands
The Teslin Plateau consists of an upland surface 1830 to 2130 m in elevation. It is dissected into large blocks by the wide valleys of Atlin and other lakes and tributary valleys of the main rivers. Evidence of glaciation is widespread on the widely flaring valleys and gently sloping upland surfaces. The Nisutlin Plateau is located east of Teslin Plateau and apart from several high points between 1220 and 1525 m, much of the country is low lying and covered with glacial drift; numerous small lakes occupy depressions in the drift (Holland 1964).
No detailed subsurface information, office or field studies on the ground water potential of the Yukon Plateau is available.
Stikine Plateau
The Stikine River between the Coast Mountains on the west and the Cassiar Mountains on the east, drains a large area of dissected plateau country called the Stikine Plateau. On the north the Stikine Plateau merges in the Yukon Plateau, it is bounded on the west by the Boundary Ranges, on the south by the Skeena Mountains (see Chapter 8, Figure 8.7). For the most part the plateau lies below the level of the surrounding mountains located to the west, south and east (Holland 1964).
The plateau according to Holland (1964) was completely covered by glacial ice during the Pleistocene, which eroded upland surfaces and deposited a veneer of drift over most of the country. Blockage by ice or drift diverted the drainage of Dease Lake northward into the Liard. Within the plateau, depressions of glacial origin, are occupied by numerous lakes and drainage is often poorly established.
There is only limited information available from well logs or ground water reports on field or office studies within the Stikine Plateau area.
Preliminary investigations at Telegraph Creek show a limited thickness of surficial deposits on the volcanic bedrock within the terraced river valley indicating only limited ground water potential (Jaundrew, 1973).
Dease Lake Townsite area, according to (Livingston 1974), was underlain by a raised delta built from the south into Dease Lake when the lake was at a much higher level than at present.
Investigations for ground water supply at Dease Lake, (Livingston, 1974), show that the kettled deltaic deposits which underlie the entire area between the Tanzilla River and the swamp at the south end of Dease Lake, are probably water-bearing and that good quality water in moderate quantity can be obtained from wells located in the area. The ground water is a good quality calcium bicarbonate type water of moderate hardness.
Conservative estimates of the capacities of two test production wells at Dease Lake are 10.1 and 37.1 L/s. The well water is warm, 12° C to 16° C and this may be associated with a deep flow system of warm water along the steep east-west fault which is clearly visible west of the valley (Livingston, 1974). Transmissivities of 2.9 X 10-2 m2/s to 3.6 X 10-2 m2/s are reported for the aquifer.
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