A method for uncertainty constraint of catchment discharge and phosphorus load estimates

Michael J. Hollaway, Keith J. Beven, Clare Mc W. H. Benskin, Adrian L. Collins, Robert Evans, Peter D. Falloon, Kirsty J. Forber, Kevin M. Hiscock, Ron Kahana, Christopher J. A. Macleod, Mary C. Ockenden, Martha L. Villamizar, Catherine Wearing, Paul J. A. Withers, Jian G. Zhou, Nicholas J. Barber, Philip M. Haygarth

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9 Citations (Scopus)
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Abstract

River discharge and nutrient measurements are subject to aleatory and epistemic uncertainties. In this study, we present a novel method for estimating these uncertainties in colocated discharge and phosphorus (P) measurements. The “voting point”‐based method constrains the derived stage‐discharge rating curve both on the fit to available gaugings and to the catchment water balance. This helps reduce the uncertainty beyond the range of available gaugings and during out of bank situations. In the example presented here, for the top 5% of flows, uncertainties are shown to be 139% using a traditional power law fit, compared with 40% when using our updated “voting point” method. Furthermore, the method is extended to in situ and lab analysed nutrient concentration data pairings, with lower uncertainties (81%) shown for high concentrations (top 5%) than when a traditional regression is applied (102%). Overall, for both discharge and nutrient data, the method presented goes some way to accounting for epistemic uncertainties associated with nonstationary physical characteristics of the monitoring site.
Original languageEnglish
Pages (from-to)2779-2787
Number of pages9
JournalHydrological Processes
Volume32
Issue number17
Early online date28 Jun 2018
DOIs
Publication statusPublished - 15 Aug 2018

Keywords

  • discharge
  • epistemic and aleatory uncertainty
  • nutrient load
  • rating curve
  • voting point

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