The chemistry, mineralogy, and rates of transport of sediments in the ...

1
INTRODUCTION
In regions of northern Canada underlain by continuous or discontinuous
permafrost (Brown, 1970), natural and man-induced changes in the thermal
regime of high ice-content, fine-grained soils usually result in thermal
erosion (Mackay, 1970). The thermal regime of these northern frozen soils
has been influenced'by climatic amelioration (Lachenbruch et al ., 1962 ;
Crampton, 1973), proximity to unfrozen water bodies (Lachenbruch et al .,
1962 ; Judge, 1973 ; Crampton, 1973 ; McRoberts and Morgenstern, 1973 ; Code,
1973 ; Mackay, -1963 ; Johnson and Brown," 1969), fire (Lotspeich et al ., 1970 ;
Mackay, 1970 ; Heginbottom, 1973 ; Wein and Weber, 1974 ; Kurfurst, .1973 ; Bliss,
1973), changes in, or removal of vegetation (Bliss, 1973 ; Heginbottom, 1973 ;
Haag and Bliss, 1974),
vehicular or animal traffic (Mackay, 1970 : Heginbottom,
1973 ; Hernandez, 1973 ; Rickard and Slaughter, 1973 ; Radforth, 1973 ; Strang,
1973 ; Kurfurst ; 1973 ; Beattie et-aZ .,"1973),and roads, seismic line clearings
and pipeline construction (Legget and MacFarlane, 1972 ; Lachenbruch, 1970 ;
Kurfurst, 1973 ; Bliss, 1973 ; Mackay, 1970 ; Strang, 1973) . In the Mackenzie
and Porcupine River Valleys, the distribution of terrain that is likely to be
disturbed by development (roads, pipeline construction) has been described
and mapped, based on vegetation, soil, permafrost, and surficial geological
information (Crampton, 1973 ; Zoltai and Pettapiece, 1973 ; Zoltai and Tarnocai,
1974 ; Lavkulich, 1973 ; Rampton, 1974 ; Tarnocai, 1973 ; Forest Management
Institute, 1974 ; Hughes, 1972 ; Rampton and Mackay, 1971 ; Rutter et al ., 1973) .
If high ice-content, fine-grained frozen soils on slopes are unwisely disturbed
by construction and development, the resulting slurry of water and
sediment will move downslope to streams, rivers and lakes . There exist only
limited data on the necessary hydrological and meteorological parameters
required to estimate the sediment transport capacity of most rivers and streams
of the Mackenzie Valley and northern Yukon (Davies, .1973 and 1974 ; Water Survey
of Canada, 1970 ; Mackay, 1973 ; McDonald and Lewis, 1973 ; Hopkins et aZ .,1955 ;
Williams,'1970 ; Church, .1974 ; Newb%ry, 1974 ; Anderson, 1974 ; Dingman, 1973a
and 1973b' ; Burns, 1973 and 1974) . Very limited data are available for estimates
of the natural variation of suspended sediments, bed load, and discharge
in rivers of this region (Davies, 1974 ; McDonald and Lewis, 1973 ; Brunskill
al ., 1973) .
Hynes (1973) indicated . that sediment added-to temperate and tropical
streams (in excess of the maximum suspended sediment load of the stream) will
be deposited on the stream,bottom, and will deleteriously affect the habitat
of fish and other aquatic organisms ., In surveys of Mackenzie Valley and
northern Yukon fish resources, Hatfield (1972), Stein et al . (1973), Jessop
et al . (1974), Dryden et al . (1973) ;,, Bryan et al . (1973), and Bryan (1973)
have expressed great concern that "siltation" might be deleterious to northern
fishes, although no observational or, .experimental demonstration of the effect
of increased sedimentation on northern fish was given . Rosenberg and Snow
(197`. nd Brunskill et aZ_.(1973) showed, by experiment and observations,
* The second in a series of 13 technical reports on ecological studies of
aquatic systems n the )Iackenzi~e and Porcupine drainages in relation to
proposed pipeline and highway development .