Numerical modelling of mine pollution to inform remediation decision-making in watersheds

Prioritisation of mine pollution sources for remediation is a key challenge facing environmental managers. This paper presents a numerical modelling methodology to evaluate potential improvements in stream water quality from remediation of important mine pollution sources. High spatial resolution synoptic sampling data from a Welsh watershed were used to calibrate the OTIS solute transport model. Simulation of mine pollution remediation scenarios using OTIS revealed decreases in stream Zn concentrations between 9% and 62% under mean streamflow conditions. Remediation scenarios under low streamflow conditions were less effective (<1% to 17% decrease in Zn concentrations), due to diffuse and metal-rich groundwater inflows.