A Framework for Untangling Transient Groundwater Mixing and Travel Times

Understanding the mixing between surface water and groundwater as well travel times in vulnerable aquifers is crucial to sustaining a safe supply. Age dating tracers used infer apparent typically refer entire sample. A sample, however, consists of mixture waters with distribution times. only reflect proportion that under range tracer, thus their interpretation biased. Additionally, end-member models are subject various sources uncertainties, which neglected. In this study, we introduce new framework untangles ratios using novel combination in-situ noble gas analyses. We applied approach during pumping test carried out pre-alpine Swiss valley. First, calculated transient recently infiltrated river regional present wellfield, helium-4 concentrations combined Bayesian model. Having identified fraction (Frw) consequently allowed us from estimated based on radon-222 activities Frw. Furthermore, compared tracer-based estimates Frw results calibrated numerical demonstrate (i) partitioning major enables meaningful an age tracer interest (ii) streambed has control