Site Assessment for MAR through GIS and Modeling in West Coast, South Africa

Abstract

Towns along the West Coast of South Africa are facing water shortages due to climate change and increasing water demand. Managed aquifer recharge (MAR) is considered as a solution to improve water security. This paper presents a two-step method of combining geographic information system (GIS) based analysis with numerical modeling to select suitable sites for implementing MAR in the West Coast area. Many factors were taken into account to generate the initial map for suitable sites through GIS based analysis. Subsequently, groundwater flow modeling was adopted to verify and optimize the suitable sites selected by GIS based analysis. The result showed that the map for suitable sites produced by the GIS based analysis was reasonable from a spatial aspect, but due to the lack of groundwater seepage information, the most suitable sites developed are not necessarily the optimal choices in practice. With the aid of both the spatial analysis in GIS and seepage simulation, this two-step analysis approach provides a reliable solution to identify suitable sites for implementing MAR. This approach provides a much better reference to the study of suitable sites and possible impacts of implementing MAR in an aquifer in similar areas with water stress.

Identifying Agricultural Managed Aquifer Recharge Locations to Benefit Drinking Water Supply in Rural Communities

“…MCDA approaches are increasingly supported or coupled with numerical modeling to provide more detailed and quantitative assessment of MAR opportunities and impacts (Sallwey et al., 2019; Zhang et al., 2019). Among the existing studies, Russo et al.…”

“…Zhang et al. (2019) conducted a GIS‐based MCDA analysis to determine suitable MAR sites along the West Coast of South Africa. They used MODFLOW and particle tracking (MODPATH) to trace the recharged water and concluded that the GIS analysis alone did not necessarily identify the most suitable sites.…”

“…GIS-based MCDA techniques integrate various thematic layers and/or their individual features using a set of weights, a process for which no standard exists (Giove et al, 2009). MCDA approaches are increasingly supported or coupled with numerical modeling to provide more detailed and quantitative assessment of MAR opportunities and impacts (Sallwey et al, 2019;Zhang et al, 2019). Among the existing studies, Russo et al (2015) used a MODFLOW-2005 model of the Pajaro Valley in California to evaluate MAR project placement and operational parameters of potential infiltration basins.…”

“…They concluded that combining a GIS-based MCDA analysis with a hydrogeologic model allowed assessing the relative benefits of different MAR scenarios and helped in assuring spatial data quality in the MCDA analysis. Zhang et al (2019) conducted a GIS-based MCDA analysis to determine suitable MAR sites along the West Coast of South Africa. They used MODFLOW and particle tracking (MODPATH) to trace the recharged water and concluded that the GIS analysis alone did not necessarily identify the most suitable sites.…”

Assessing Aquifer Water Level and Salinity for a Managed Artificial Recharge Site Using Reclaimed Water

“…Numerical modelling and hydro-geochemical investigations were often used by scientists to estimate aquifer storage or to carry out groundwater recovery based on exploratory simulations and scenarios development [8,9,[21][22][23][24]. They can also help to estimate the potential benefits for constructed structures on hydrologic conditions under a range of management scenarios.…”