Regression Approaches for Hydrograph Separation: Implications for the Use of Discontinuous Electrical Conductivity Data

Abstract

Understanding of runoff generation mechanisms affects the ability to manage streamflow quantity and quality issues. Concerning the baseflow in particular, measurements are almost never available and hydrograph separation is generally applied to characterize its relevant patterns. As an alternative to well-known recursive digital filters and mass balance filtering methods, this paper deals with the use of regression approaches, based on electrical conductivity measurements, as a proxy for total dissolved solids, to separate baseflow from total flow. Particular focus is placed on their flexibility and ability to adapt to discontinuous electrical conductivity data measurements.To illustrate this, we analyze a hydrochemical dataset collected from the Ciciriello experimental catchment (Southern Italy). The main findings are as follows: A comparative analysis suggests that the performance of regressive approaches in the case of daily electrical conductivity measurements is better than that of calibrated recursive digital filters. Weekly monitored electrical conductivity data led to performances comparable to the daily scale monitoring, and even monthly observation leads to a nonsignificant reduction in regression hydrograph filter performance; this shows how spot geochemical data monitoring may present valid and operational alternatives for characterization of baseflow in poorly gauged catchments.

Variabilidade da resposta hidroquímica a eventos de precipitação utilizando monitoramento de alta frequência em bacias hidrográficas subtropicais, sul do Brasil

“…Such measurements would give important information about the water origins at the river basin's outlet for hydrograph separation (e.g. Matsubayashi et al, (1993), Pellerin et al (2008), Longobardi et al (2018), Cano-Paoli et al (2019)).…”

Worldwide Research on Geoparks through Bibliometric Analysis

“…Another emerging line is Cluster 8 (brown), 'Geo-tourism in Karst System'. This type of relief formed by the chemical precipitation of carbonate rocks has led to investigations of the karst environment; e.g., its hydrological and hydrogeological characteristics have been an object of study in the Cilento, Vallo di Diano, and the Alburni geopark of Italy [199][200][201][202][203][204][205][206][207]. Karst systems are vulnerable to contamination, constitute a geological element with significant geo-tourism value, and can contribute to the environmental awareness of this type of geo-resource [223].…”

“…The members of this cluster highlight how geo-tourism promotes conservation and geo-education in karst areas. The authors of this research area have carried out hydro-geomorphological studies and hydro-chemical monitoring activities in Southern Italy in Cilento, Vallo di Diano, and the Alburni UNESCO Global Geopark [199][200][201][202][203][204][205][206][207]. Studies have been done on the 'Middle Bussento Karst System', the second-longest karstic system in Italy [208], and on geo-sites and geo-tourism in Southern Italy [209,210].…”

Optimal Baseflow Separation Through Chemical Mass Balance: Comparing the Usages of Two Tracers, Two Concentration Estimation Methods, and Four Baseflow Filters

“…This is because the measurements of tracer, such as specific electrical conductance (SEC), isotope concentration, and turbidity, are typically available only from the 1990s onwards and are characterized by higher intermittency (only for flood/drought season or events) and coarser resolution (daily or coarser) (Foks et al., 2019; Halder et al., 2015; Putman & Bowen, 2019), despite the long‐term continuous streamflow measurements available for the catchments. To overcome these issues and to better leverage the environmental tracer data, CMB is often combined with an empirical method with lower data requirements (Cartwright, 2022; Hagedorn, 2020; Longobardi et al., 2018). Empirical methods using streamflow time series as the only input can construct baseflow time series for the whole streamflow record.…”