Towards modelling Wairau River – Aquifer exchange flux dynamics: Data integration and upscaling

Abstract

The Wairau Aquifer is almost exclusively recharged by surface water from the Wairau River and serves as the major drinking water resource for Blenheim and the surrounding settlements on the Wairau Plain. Because the safe yield limit of the aquifer has been reached and a small but constantly declining trend in aquifer levels have been observed over the past decade, it has been made a high priority by the Marlborough District Council (MDC) to better understand the limits and the mechanics of the recharge mechanism. While previous research efforts have been centred at water budgets during low-flow conditions and steady-state modelling, this study aims at understanding the dynamics of river-groundwater exchange fluxes using information of Wairau river flows at three new gauging stations.