Prior to the arrival of field personnel for the 1990 field season at Taconite Inlet, nothing was known about any aspect of streamflow into Lake C2. Although aerial photographs (1:7,000 scale) suggested that monitoring could be done on a large fan-foreset delta, the morphology and stability of the channel, as well as the magnitude of discharge, were complete unknowns. Logistical constraints limited the amount of material available for use (e.g. precluding weirs), and dictated that streamflow measurement be accomplished through the use of a rated section.
A single gage site and rated section was utilized through the three field periods, except for the first two days of 1990, and first day of 1992. (IMAGE: gaging station) The site selected was the best, and possibly the only, option on the delta, and located 350 m upstream from the lake. Section control was provided by a downstream riffle until high flows, when the left edge of the channel began to be submerged. Lateral and longitudinal profiles through the rated section were made using a Nikon model AZ-1 autolevel and a surveying rod. The longitudinal stream gradient, from 80 m above to 80 m below the rated section, was 2.0°.
The channel bed was comprised of material ranging in size from fine sand to medium boulders, which resulted in turbulent flow at all discharges. Particle size was highly variable along the channel, but was primarily coarse gravel to cobble size at the rated section.
In addition to the principal stream entering Lake C2, there were five other minor streams, which were not monitored regularly. (IMAGE: topographic map) These streams were observed to flow for a much shorter period of time each year, with much smaller discharges. The largest minor stream, entering the northwest corner of Lake C2, was measured once during relatively high discharge at 0.15 m^3 s^-1. For perspective, discharge from the principal stream one hour later was 3.27 m^3 s^-1 (22 times greater).
All sediment flux sampling was done at the stream gaging station site, at one or more points across the rated section. (IMAGE: gaging station) The sampling emphasis was confined to this single site, proximal to Lake C2, to permit maximal sampling frequency.
The stream channel at the sampling site varied in width from 3 to 8 m, and from 10 to 50 cm in depth at the deepest point, depending on discharge. The bed of the stream was typical of small mountain streams, in that sediments spanned a broad size range, and induced turbulent flow at all discharges.
Early in each of the seasons, the channel bed was largely armored by ice, and considerably less rough than later in the season. The channel ice was present along the channel thalweg prior to streamflow initiation, indicating formation during freeze-up the previous year. In addition to this residual ice, ice also aggraded on the channel bed, particularly over the largest rocks, when the channel-clearing slushflow exposed streamwater to the sub-freezing temperature of the channel. (IMAGE: early stream channel) Due to the effect of this ice on channel bed roughness and resistance to flow, the extent of ice was noted in association with the acquisition of all sediment samples.