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

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Only two clay minerals were found, chlorite and illite, and these
were, common in nearly all samples . Kaolinite and members of the montmorillonite
group . were sought but not found . See Campbell et aZ . (1975)
for specific data for individual rivers and lakes .
Nutrients N, P, and C in Suspended Sediments
Concentrations of C, N, and P in suspended sediments (PC1,, PN : and PPS)
of river waters are given in Table 7a and 7b . Variations in concentrations
of these elements in the particulate phase were likely due to changes a) in
concentration of suspended sediments, and b) in the relative proportions
of inorganic and organic material in suspended sediments . The proportion
of C, N, and P per unit weight of suspended sediments is greater in the
smaller Group 2 streams, compared to the larger rivers of Group 1 (Table 7b) .
Per unit volume of river water, instantaneous concentrations of PP, :, PN,-
and PC, : were related to instantaneous discharge (Qi) as indicated in Figs . 3
and 4 . With increased discharge, there was usually an increase in concentrations
of PN1, PP, :, and PC, :, with the exception of rivers in Group 3 .
Mean annual rates of transport of na, P91a, and gPQ in suspended sediment
are given in Table 8, 9, and 10 . In general, Group 1 watersheds
transported greater amounts of PC, PN, and PP (in units of moles yr'1 and
moles kin-2 of watershed area yr'l) than did Group 2 rivers and streams of
Table 1 . The annual mass of PCW, PNu,, and PPW transported per unit watershed
was also positively related to annual discharge (QQ) as shown in FiRs .5
and 6 . With increasing annual discharge, the transport of PCW, PNw, and PP ; .. .
from a square kilometer of watershed also increased . Small Qa rivers and
streams (Group 2 in Table 1) in the Mackenzie Valley lowlands yielded less
PCW, PNu., and PP,, ., per unit watershed area than did the larger Qa rivers of
Group 1 .
The concentrations of PC, :, PN1 and PP, : (moles m'3 of river water)
.increased exponentially per unit increase in the concentration of suspended
sediments (Table 11) . The slopes of the regression lines were of similar
magnitude for PC, :, PN: and PP,: . - :The mean annual rates of transport of
suspended sediments (SSW in kg k~'2yr'1), PCW, PNW, and PPW (in moles
km- yr-1) increased exponentially per unit increase in annual discharge
(Table 12 and Figs . 2, 5 & 6) .
An attempt was made to provide a means of "order of magnitude" prediction
of na, . Ts a, TNQ, and TPQ from parameters that can be obtained from
topographic,, climatic, vegetation and geologic maps . The results of multiple
linear regression analyses given in Table 13 indicate that watershed area,
forest cover, relief, and precipitation are useful parameters in estimating
the annual mass of suspended sediments and particulate nutrients flowing out
of a Mackenzie Valley watershed . -Estimates of annual transport (metric tons
yr-1) of the above mentioned elements can be obtained from the following
equations :