H086-0001
What information from reach-scale tracer experiments can be effectively upscaled to represent longer study reaches?
Thursday, 10 December 2020
Poster
Adam S Ward, Indiana University, School of Public and Environmental Affairs, Bloomington, IN, United States, Michael N Gooseff, University of Colorado at Boulder, Institute of Arctic and Alpine Research, Boulder, CO, United States, Ken Bencala, Organization Not Listed, Washington, DC, United States, Tim P Covino, Colorado State University, Ecosystem Science and Sustainability, Fort Collins, CO, United States, Skuyler P Herzog, Indiana University, School of Public and Environmental Affairs, Bloomington, United States, Brian L McGlynn, Duke University, Nicholas School of the Environment, Durham, NC, United States, Robert Alden Payn, Montana State University, Department of Land Resources and Environmental Sciences, Bozeman, MT, United States, Noah M Schmadel, UWRL, Logan, UT, United States and Steven M Wondzell, USFS - Pacific Northwest Research Station, Corvallis, OR, United States
Abstract:
Accurate prediction of river corridor exchange at the scale of river networks is recognized as increasingly important to river management and as part of global models. However, most empirical studies of river corridor exchange focus on reaches of a few hundred meters or smaller, while continental and global models necessarily discretize the river network more coarsely. To predict the transport and transformation associated with river corridor exchange at larger scales, new strategies are needed to translate findings across scales and make predictions in unstudied locations. The common assumptions for upscaling tracer-based characterization of exchange from short study reaches to longer reaches and eventually networks do not appear to be met based on (a) the documented emergent controls on channel water balance with increasing scale, and (b) known limitations of solute tracer studies. However, the existence of idiosyncratic observations does not unto itself support robust conclusions about stream solute tracer studies as a basis for reach-to-network scaling.
The overarching objective in this study is to test if aggregation of reach-scale solute tracer studies are an appropriate basis for predictions of river corridor transport at the network scale. Specifically, we ask (1) is different information about river corridor exchange interpreted from reaches of different lengths? and (2) can observations at one spatial scale be convolved to describe channel water balance in longer reaches? To answer these questions, we consider a series of experiments spanning 2,800-m of river corridor, studied as a series of both 100-m and 200-m reaches. We interpret recovered solute using established methods for reach-scale solute tracers and tested differences between the study scales. Ultimately we demonstrate a new approach to quantify the uncertainty associated with methodological limitations of stream solute tracers.
