Sediment Yield Methods
NTU- and Q-based (loge transformed) modeled SSCs (converted from mg L-1 to mg m-3) were multiplied by discharge separately to give sediment yield (mg s-1) and converted to integrate mass over longer periods (Mg yr-1). Confidence and prediction intervals for modeled SSCs were calculated in R, then converted to lower and upper yields using the same method. NTU- and Q-based half-hourly or hourly sediment yields (depending on the interval of model parameters) were bridged by taking the period of available NTU-based yields and subsequently filling gaps where NTU-based yield values were not available with Q-based yield values, to give continuous records of sediment yield for both Carnivore and Chamberlin Creeks for the majority of the 2015 and 2016 open-channel seasons. For early- and late-season, when modeled SSCs could not be predicted with either NTU- or Q-based models due to lack of data, average sediment yield below the corresponding estimated low-flow discharge estimated from photographs and field notes was used (< 10 m3s-1 and < 5 m3s-1 in Carnivore Creek; < 0.25 m3 s-1 in Chamberlin Creek). Subsequently, sediment yields for the entire open-channel seasons in both creeks could be estimated. We used May 18 to September 17 as the open-channel period, based on data availability and field photographs. During mid-May when flows were ice affected, field observations and photographs indicate that our dataset may exclude up to one week of low-flow water and sediment discharge. We are confident that no significant late-season events were missed based on photographic evidence and regressions of Q from our study with the nearby Hula Hula River discharge (U.S. Geological Survey gauge 15980000), with the latter explaining about half the late season Q variability.

Results