Studies of sedimentary processes and annual sediment accumulation rates in Lake C2 demonstrate a close link to hydrologic processes. Hardy (1996) and Hardy et al. (1996) have, in turn, demonstrated the close linkage between climate, hydrology and suspended sediment flux in the main inlet stream. In addition, this study has shown that the sediment flux into the bottom of Lake C2 approximates that contributed by the main inlet source and also the accumulation rate as determined from measurement of individual laminae.
Sediment delivery to the Lake C2 system is dominated by fluvial processes. The fluvial inputs are distinctly seasonal and contribute sediment to Lake C2 predominantly during snowmelt runoff events, which are, in turn, largely controlled by seasonal warm episodes (Hardy, 1996). Thus, the inputs into the lacustrine system are closely linked to climatic controls.
Sediment transported to the lake is dispersed efficiently across the lake basin in a plume-shaped pattern by overflow and interflow processes emanating from the main inlet. The inlet sediment plume enters the water column along distinct density gradients. In the early season, overflows dominate the dispersal pattern as cold near-freezing meltwater with low sediment concentrations flow in the upper 2 meters underneath the lake ice cover. In the latter part of the season higher concentration flows enter the lake and descend to the halocline and travel downlake as interflows.
Sediment trap yields for each summer field season compare well with suspended sediment concentrations measured at the main inlet stream for the same period. Annual sediment trap yields determined for May 1991 to May 1992 also quite similar to predicted annual sediment flux and sediment accumulation rates determined from lamination thickness studies.
