Sediment Yield Results
NTU-based multiple-regression models explain more variability in SSCs than Q-based models (Table 3), making them our first choice for predicting annual sediment yields. However, the turbidity sensor failed at times, and there are no substitutes for NTU measurements, such that NTU-based models could not be used alone. Q-based models could be applied with fewer gaps, but data were still lacking for the shoulder periods of each season. Photographic and field observation evidence of Q during ungauged shoulder periods led us to use average SSCs at low flows to fill early- and late-season gaps. Bridging the three methods in preferential order allowed sediment yields to be estimated (Table 4). Given that there is minimal sediment transfer at low flow, using our approximation for shoulder periods makes little difference to the estimated sediment yields; 5.4% and 13% (2015) and 0.17% and 1.7% (2016) of the total open-channel season sediment yield in Carnivore and Chamberlin Creeks, respectively, was approximated from average SSCs at low flow. Furthermore, our sediment yield results are supported by estimates based on sediment accumulation rates measured in Lake Peters (Thurston, 2017). Total seasonal suspended sediment discharge into Lake Peters from Carnivore Creek is one or two orders of magnitude higher than suspended sediment discharge from Chamberlin Creek, with the former contributing 96% of the total yield from these two major tributaries (Table 4). When normalized by catchment area and averaged across 2015 and 2016, the specific sediment yields were 58 and 33 Mg km-2yr-1 from Carnivore and Chamberlin Creeks, respectively. Sediment yield for Carnivore and Chamberlin Creeks is 59% and 37% greater, respectively, in 2016 than 2015. Most of the suspended sediment loads in both creeks are transported within a few days during discrete events (Figure 5). In Carnivore Creek, over 49% and 50% of the sediment yield is modeled to have been discharged in 48 consecutive hours for 2015 (August 3-5) and 2016 (July 7-9), respectively. In Chamberlin Creek, 12% and 57% of the sediment yield is modeled to have been discharged in 48 consecutive hours for 2015 (August 3-5) and 2016 (July 7-9), respectively.

Discussion