A software tool to assess uncertainty in transient-storage model parameters using Monte Carlo simulations

Adam S. Ward, Christa A. Kelleher, Seth J.K. Mason, Thorsten Wagener, Neil McIntyre, Brian McGlynn, Robert L. Runkel, Robert A. Payn

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Researchers and practitioners alike often need to understand and characterize how water and solutes move through a stream in terms of the relative importance of in-stream and near-stream storage and transport processes. In-channel and subsurface storage processes are highly variable in space and time and difficult to measure. Storage estimates are commonly obtained using transient-storage models (TSMs) of the experimentally obtained solute-tracer test data. The TSM equations represent key transport and storage processes with a suite of numerical parameters. Parameter values are estimated via inverse modeling, in which parameter values are iteratively changed until model simulations closely match observed solute-tracer data. Several investigators have shown that TSM parameter estimates can be highly uncertain. When this is the case, parameter values cannot be used reliably to interpret stream-reach functioning. However, authors of most TSM studies do not evaluate or report parameter certainty. Here, we present a software tool linked to the One-dimensional Transport with Inflow and Storage (OTIS) model that enables researchers to conduct uncertainty analyses via Monte-Carlo parameter sampling and to visualize uncertainty and sensitivity results. We demonstrate application of our tool to 2 case studies and compare our results to output obtained from more traditional implementation of the OTIS model. We conclude by suggesting best practices for transient-storage modeling and recommend that future applications of TSMs include assessments of parameter certainty to support comparisons and more reliable interpretations of transport processes.

Original languageEnglish (US)
Pages (from-to)195-217
Number of pages23
JournalFreshwater Science
Issue number1
StatePublished - Mar 2017


  • Hyporheic zone
  • Inverse modeling
  • MCAT
  • OTIS
  • Parameter estimation
  • Solute transport
  • Tracer
  • Transient storage

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Aquatic Science


Dive into the research topics of 'A software tool to assess uncertainty in transient-storage model parameters using Monte Carlo simulations'. Together they form a unique fingerprint.

Cite this