Synthesizing existing frameworks to identify the potential for Managed Aquifer Recharge in a karstic and semi-arid region using GIS Multi Criteria Decision Analysis

Abstract

Imbalance between water supply and demand is increasing in many parts of the world. Lack of water security is attributed to climate change, population growth and unsustainable abstraction of groundwater. Managed Aquifer Recharge (MAR) can increase groundwater recharge, facilitate higher water availability and accessibility, and hence reduce water supply deficit. This paper investigates the potential of MAR in a karstic and semi-arid region with the use of GIS Multi Criteria Decision Analysis (GIS-MCDA). While previous studies have focused on MAR techniques and MAR suitably mapping separately, this paper combines technique selection and suitability mapping to emphasize the importance of considering both. The methodology was applied for a karstic and semi-arid region, using the Ramotswa Transboundary Aquifer Area (RTAA) as case study. MAR suitability mapping of the selected MAR technique was carried out with six thematic layers using Weighted Linear Combination (WLC) decision rule. The objective was to identify suitable areas for implementation of spreading methods and generate MAR suitability maps to guide decision-making in such implementation. The suitable areas were identified at the border between Botswana and South-Africa. The study develops a methodology for GIS-MCDA considering spreading method for a karstic aquifer, but more research is needed to assess the methodological transferability to other karstic and semi-arid regions.