Revisiting hysteresis of flow variables in monitoring unsteady streamflows

Abstract

Conventional streamflow monitoring methods entail one-to-one relationships between two flow variables obtained by combining direct flow measurements with statistical analyses. These relationships (i.e. ratings) are used to monitor both steady and unsteady flows despite that in the latter cases the flow variables display an inherent hysteretic behaviour. Such behaviour is prominent if the wave passing through the gauging station is non-kinematic. This paper demonstrates that the index-velocity and continuous slope-area methods are more suitable to monitor unsteady flows in comparison with the widely used stage-discharge approach. Case studies are presented to show that, contrary to current perceptions in practical applications, hysteresis can be captured even in small streams and frequently-occurring runoff events. The paper also highlights the separation of the flow variable hydrographs in unsteady flows. This hysteresis-related aspect is less investigated so far despite having important practical implications for both hydrometric and fluvial transport applications.

Nitrate Removal and Woodchip Properties across a Paired Denitrifying Bioreactor Treating Centralized Agricultural Ditch Flows

“…A non-linear regression relating water depth and velocity was used to estimate flow between site visits (Supplemental Figure S5; R 2 = 0.80). A random error of 5% was assumed for in-ditch daily flow measurements, when developing the depth-velocity relationship [16], and uncertainty of cumulative annual flow was calculated by adding uncertainties for daily flow in quadrature (i.e., taking the square root of summed squares of absolute daily uncertainties).…”

Advanced methods to investigate hydro‐morphological processes in open‐water environments

“…Baranya et al, 2015; Guillén‐Ludeña et al, 2016), but also to investigate short‐term events and their influence on the hydro‐morphological system. One example is the observation of downstream suspended sediment concentrations during reservoir flushing, for example to quantify the amount of eroded sediments, or investigations on the hysteresis effect of water and transported sediments, for example during flood events (Hauer et al, 2020; Landers & Sturm, 2013; Muste et al, 2020). Long‐term monitoring is often used to provide deeper understanding of the system itself.…”

Decoding the Hysteretic Behavior of Hydraulic Variables in Lowland Rivers with Multivariate Monitoring Approaches

“…Despite the exponential increase in efforts, acceptable solutions are only available for a limited number of practical problems. Moreover, the outcomes of theoretical studies are rarely validated with experiments as the data from laboratory studies are affected by multiple scaleinduced distortions and the much-needed data from natural streams are rarely available (Muste et al, 2020) or uncertain (di Baldassare & Montanari, 2009).…”

“…The conventional IVRC and CSA monitoring approaches were revitalized by the assimilation of contemporary instruments, mostly based on acoustic principles. Details on the capabilities of exiting monitoring methods document hysteresis flows are discussed in Muste et al (2020) and Muste et al (2022a).…”