Ground Water Resources of British Columbia
Chapter 9 — Ground Water Resources of the Basins, Lowlands and Plains
9.2.3 LIARD PLAIN AND NASS BASIN
by
J. C. Foweraker
Liard Plain
The Liard Plain lies within the drainage area of the Liard River and its tributaries and is a low area of slight relief (Chapter 8, Figure 8.5). The plain is to a large extent surrounded by plateaus and mountains of considerably greater elevations. To the south the plain merges with the Rocky Mountain Trench (Holland, 1964).
The Liard Plain was completely covered by glacial ice and glacial sculpturing is very evident today. According to Holland (1964) ice moved across the plain and shaped and modelled bedrock and drift into drumlin like forms parallel to the direction of ice movement. Shallow lakes now fill depressions previously gouged out by ice, and eskers and morainal features are clearly shown on air photos.
No subsurface information, office or field studies on ground water potential of the Liard Plain are available except for Lower Post, where a preliminary investigation for a well site for Lower Post school recommended test well drilling in sand and gravels of the lower terraces of the Liard River Valley.
Southeast of Lower Post at the Hyland River Park a well yielding 27.3 L/min was completed in a silty, sand and gravel aquifer. The aquifer was encountered at a depth of 12.8 m and extended down to 17.4 m. The aquifer is overlain by clays and silts.
Nass Basin
The Nass Basin is of low relief, most below 760 m elevation, and it is drained by the Nass River and its tributaries and by tributaries of the Skeena River. Holland (1964) describes the basin as extending from the junction of Teigen Creek with the Bell Irving River south-eastward for 209 km to the Skeena river at Hazelton (see Chapter 8, Figure 8.5). The maximum width of the basin, northeasterly from Hazelton at Swan Lake, is about 40 km. The basin is encircled by mountains which rise abruptly from the gently rolling floor of the basin. Bedrock underlying the basin is dominantly volcanic (Holland, 1964). The basin was occupied by glacial ice and the numerous depressions now lakes are of glacial origin.
Available information on ground water potential is limited to a few well records and preliminary studies for ground water availability at New Hazelton, Kitwanga and Meziadin Lake.
In the area around New Hazelton a discontinuous sand and gravel aquifer up to 7.6 m thick underlies a 38 - 53 m thick blue bouldery till. Wells completed in this aquifer may produce 45 - 103 L/min. The static water level in some of these wells may be as deep as 37 m. Some potential for ground water development exists in shallow sands and gravels along some areas of the Bulkley River but silt content in the ground water during spring freshet may be a problem.
A 305 mm production well 30 m deep near Kispiox Village north of Hazelton was constructed in a 21 m thickness of sand and gravel, for a fish hatchery. The well was tested at 75.7 L/s. Transmissivity is 1.7 X 10-2 m2/s (Wei, 1986).
Northeast of Kitwanga on the north side of the Skeena River wells have been completed for domestic and industrial uses in shallow sands and gravels, and in some instances reported yields are between 45 and 136 L/min. A 91 m deep well completed in bedrock on the upland 3.2 km northeast of Kitwanga townsite and east of the Kitwanga River has a potential yield of 45 - 68 L/min. West of Kitwanga and east of Cedarvale, wells completed in sands and gravels less than 21 m deep yield up to 45 to 136 L/min (Kohut, 1977).
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