Recession curve power-law exponent estimation: is there a perfect approach?. Issue 8 (11th June 2022)

• Record Type: Journal Article
• Authors: Sharma, Durga; Biswal, Basudev
• Is Part Of: Hydrological sciences journal. Volume 67:Issue 8(2022)
• Page Start: 1228
• Page End: 1237
• Publication Date: 2022-06-11
• Subjects: recession curve parameter estimation -- Brutsaert-Nieber equation -- power-law relationships -- discharge prediction -- individual recession curve analysis; Hydrology -- Periodicals; 551.4805
• DOI: 10.1080/02626667.2022.2070022
• Languages: English
• ISSNs: 0262-6667

Abstract

ABSTRACT: The coefficient ( k ) of the ( − d Q / d t ) − Q (discharge at time t) power-law relationship is typically computed after fixing the value of the exponent (α). However, recession analysis poses the challenge of finding a suitable α for a basin. Although many recent studies have suggested considering the median of the α distribution as the representative value, a purely logical reasoning for this has not been yet provided. In this study, we argue that there is no perfect approach to estimate α and that it should depend on the final objective. Recession flow prediction is considered the objective in this study. We employ a model to predict recession discharge for 408 USGS (United States Geological Survey), basins for a wide range of α values. Considering Nash-Sutcliffe efficiency as the indicator of model performance, we observed that the optimum value of α is substantially lower than the α median for most of the basins. Overall, our study establishes that there is no single value of α preferable for all practical purposes.