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GIS-Multi Criteria Decision Analysis to identify the potential for Managed Aquifer Recharge (MAR) in a Karstic and Semi-Arid region - Case study on Ramotswa Transboundary Aquifer

GIS-Multi Criteria Decision Analysis to identify the potential for Managed Aquifer Recharge (MAR) in a Karstic and Semi-Arid region - Case study on Ramotswa Transboundary Aquifer

'GIS-Multi Criteria Decision Analysis to identify the potential for Managed Aquifer Recharge (MAR) in a Karstic and Semi-Arid region' is a thesis for the joint MSc. programme: Groundwater engineering and global change - impacts and adaptation. In this thesis, written by Sajad Fathi, the Ramotswa Transboundary Aquifer (shared by Botswana and South Africa) was used as case study. Fathi was supervised by IHE Delft and IGRAC.

Abstract

In a changing climate with incontrollable driving forces like rapid population growth and land use change, the imbalance between water supply and demand is increasing, insistently counteracting the goal of water security – particularly in developing countries. Managed Aquifer Recharge (MAR) increases groundwater recharge, facilitating higher water availability and accessibility, and hence stabilizing the aforementioned problematic deficit. This paper investigates the potential for MAR in a karstic and semi-arid region with the use of GIS Multi Criteria Decision Analysis (GIS-MCDA). The research constitutes a case study of the Ramotswa Transboundary Aquifer Area (RTAA). The objective is to identify suitable methods and locations for implementation of MAR in order to better balance water supply and demand. The aim of the study is to provide MAR suitability maps that can guide decision-making for such implementation. Based on a comprehensive literature review on MAR in karstic and semi-arid regions, preferable MAR methods were decided upon. Likewise, six thematic layers were selected based on existing literature and data availability. Integrating normalized MAR suitability classifications with respect to all six layers based on Weighted Linear Combination (WLC) and multi influential factor (MIF) decision rule and justified weight-assignments, it was found that the suitable area with less change is related to Ramotswa Dolomite Aquifer and its surrounded area. Although most unreliable area has been distinguished at north and east of RTAA. The findings of this study highlights the potential and the need for MAR in the transboundary aquifer considered, and – although mainly targeting RTAA – some generic findings are applicable and transferable to other karstic and semi-arid regions; this aligns the following research with ongoing projects targeting water security in developing countries.

GIS-Multi Criteria Decision Analysis to identify the potential for Managed Aquifer Recharge (MAR) in a Karstic and Semi-Arid region - Case study on Ramotswa Transboundary Aquifer Area (RTAA) (Botswana and South Africa)