Abstract
Abstract. Recession analysis is a classical method in hydrology to assess watersheds' hydrological properties by means of the receding limb of a hydrograph, frequently expressed as the rate of change in discharge (-dQ/dt) against discharge (Q). This relationship is often assumed to take the form of a power law -dQ/dt=aQb, where a and b are recession parameters. Recent studies have highlighted major differences in the estimation of the recession parameters depending on the method, casting doubt on our ability to properly evaluate and compare hydrological properties across watersheds based on recession analysis of -dQ/dt vs. Q. This study shows that estimation based on collective recessions as an average watershed response is strongly affected by the distributions of event inter-arrival time, magnitudes, and antecedent conditions, implying that the resulting recession parameters do not represent watershed properties as much as they represent the climate. The main outcome from this work highlights that proper evaluation of watershed properties is only ensured by considering independent individual recession events. While average properties can be assessed by considering the average (or median) values of a and b, their variabilities provide critical insight into the sensitivity of a watershed to the initial conditions involved prior to each recharge event.
Highlights
Accurate representations of watershed-scale hydrological processes are urgent in a global- and anthropogenic-change perspective
The different fitting strategies revealed that the LE, central tendency (CT), and BA methods all fit to the point cloud and result in different values of b when applied to the observed daily averaged streamflow for Lookout Creek: early-time values of b are over 50 % larger for LE than CT and BA, and late-time values of b are 50 % and 25 % larger for LE than CT and BA, respectively (Fig. 3 and Table 2)
To examine the sensitivity of parameter estimation to recession extraction criteria, we evaluated how choosing the start of the recession affects the value of a when using the point cloud method
Summary
Accurate representations of watershed-scale hydrological processes are urgent in a global- and anthropogenic-change perspective. Streamflow recession analysis has been routinely used for about half a century to assess watershed properties (e.g., Brutsaert and Nieber, 1977; Kirchner, 2009; Mcmillan et al, 2014) and more recently their vulnerability to climatic and anthropogenic factors (Berghuijs et al, 2016; Brooks et al, 2015; Buttle, 2018; Fan et al, 2019). It has long been recognized that the accuracy in the estimation of those parameters is highly sensitive to the methods used (Chen et al, 2018; Dralle et al, 2017; Roques et al, 2017; Rupp and Selker, 2006a; Santos et al, 2019; Stoelzle et al, 2013).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
