A Novel Groundwater Sustainability Index using AHP/GIS Approach

Abstract

In the context of water scarcity and food deficit while population progressively over-increasing, agricultural expansion into deserts become urgent, this requires sustainable groundwater resources to be secured. A wide range of sustainability indicators are available in literatures but efforts are still needed to develop them into measurable indexes that help to judge the extent to which the groundwater resources are developed sustainably and to direct toward better development This work introduces a novel groundwater sustainability index developed using the Saaty’s Analytic Hierarchy Process (AHP) which is a widely used MultiCriteria Decision Analysis (MCDA) method. Five indicators have been selected in this work (Change in Water level, Renewability of Groundwater, Aquifer Saturated Thickness , Water Quality and Vulnerability Indexes ), these consider both quantitative and qualitative dimensions of the resources and reflect the economic and environmental sustainability and social well-being. The selected criteria and sub criteria have been assigned weights and rates based on their relative importance to the main goal, the weights and rates were compared with each other in pair-wise matrixes , the eigen values and consistency ratio were calculated to validate the assigned weights and rates of the selected parameters ; the ranges of these parameters are classed and rated then reclassified with GIS and RS for application of the sustainability index in pilot area. The results of hydrochemical and isotopic analysis of groundwater samples as well as mapping of inventoried data form ElKhatatba pilot area have been used for hydrochemical and hydrogeological characterization of the system and for preparation the site thematic layers on which the developed indexapplied. The overall sustainability of groundwater resources in the ElKhatatba area vary between moderate to poor grades moderate to poor grades which highlights the necessity for continuous monitoring and better management of the groundwater resources. Finally, the proposed index was validated using the change in land use with time