Effects of passive-storage conceptualization on modeling hydrological function and isotope dynamics in the flow system of a cockpit karst landscape

Abstract. Conceptualizing passive storage in coupled flow–isotope models can improve the simulation of mixing and attenuation effects on tracer transport many natural systems, such as catchments or rivers. However, effectiveness incorporating different conceptualizations complex karst flow systems remains poorly understood. In this study, we developed a model that conceptualizes both “fast-flow” “slow-flow” processes heterogeneous aquifers well hydrological connections between steep hillslopes low-lying depression units cockpit landscapes. The tested contrasting configurations fast- slow-flow was optimized using multi-objective optimization algorithm based detailed observational data discharge isotope dynamics Chenqi Catchment southwestern China. Results show one to three passive-storage zones distributed hillslope fast-/slow-flow reservoirs and/or provided optimal structures study catchment. This effectively accuracy for outlet signatures. Additionally, tracer-aided reflects dominant paths units, yielding reasonable source area apportionment components (e.g., more than ∼ 80 % fast total discharge) solute unit systems. Our provides novel, flexible tool realistic catchment easily be transferred other catchments.