Quantifying uncertainties in tracer‐based hydrograph separations: a case study for two‐, three‐ and five‐component hydrograph separations in a mountainous catchment

作者：S. Uhlenbrook, Simon Hoeg · 发表于：Hydrological Processes · 年份：2003 · DOI：10.1002/hyp.1134 · 被引用次数：204 · 研究领域：Hydrology and Watershed Management Studies、Groundwater flow and contamination studies、Groundwater and Isotope Geochemistry

Abstract The hydrograph separation technique using natural tracers, in which different runoff components are quantified according to their chemical signature, is a widely used method for investigating runoff generation processes at the catchment scale. The first objective of this study is to demonstrate a modified methodology for separating three and five runoff components using 18O and dissolved silica as tracers. The second is to evaluate, with an uncertainty propagation technique using Gaussian error estimators, the hydrograph separation uncertainties that arise due to different error effects. During four summer storm events, an interaction among three main runoff components having distinct dissolved silica concentrations was demonstrated for the mountainous Zastler catchment (18·4 km2, southern Black Forest Mountains, southwest Germany). The three main runoff components are surface storage (low silica, saturated and impermeable areas), shallow ground water (medium silica, periglacial and glacial drift cover), and deep ground water (high silica, crystalline detritus and hard rock aquifer). Together with the event and pre‐event water fractions of surface runoff and shallow ground water runoff, five runoff components are considered in all. Pre‐event water from shallow ground water storage dominated the total discharge during floods and was also important during low flows. Event water from shallow ground water was detectable only during the falling limb of a larger flood with...