Sallwey, J., Schlick, R., Bonilla Valverde, J.P., Junghanns, R., Vásquez López, F., Stefan, C. (2019)
Suitability maps for managed aquifer recharge: review and tool development.
Presentation at the 10th International Symposium on Managed Aquifer Recharge (ISMAR10). Madrid, Spain, 20-24 May 2019


Suitability maps for managed aquifer recharge (MAR) sites are increasingly derived through GIS-based multi-criteria decision analysis (GIS-MCDA). To date, there are no guidelines or common understanding on how suitability mapping should be conducted. There is considerable variability concerning the base GIS maps used and how they are weighted. To showcase the development as well as the state of the art of GIS-MCDA in the context of MAR site selection, we retrieved information on used criteria, assigned weights and utilised methodologies from 63 related studies.

The data was compiled into a web-based query tool that makes the information easily accessible and the utilization of the database more user-friendly. Based on the most commonly used practices in the assessed studies, we conceptualized and implemented an online tool that comprises a simplified webGIS as well as supporting tools for weight assignment and standardization of criteria. The online tool guides the decision maker through a structured process of suitability mapping, starting with problem definition, followed by constraint mapping and finishing with suitability mapping. Different weighting procedures, such as rank method, multi-influence factor or pairwise comparison are implemented as well as decision rules in form of weighted linear combination and analytic hierarchy process. Starting from uploading the base GIS maps for the assessment to the final suitability map, the user is supported by relating information from the database to each step of the decision making process.

This review as well as the created web-tool will help planners of MAR sites to engage in MCDA in a more structured and informed way by referring to previously conducted studies and by finding information suitable for their specific project. Suitability maps for MAR hold a strong potential for integration into sustainable groundwater management plans. However, quality of the maps strongly depends on input data quality as well as expertise of the decision maker. To decrease the uncertainty related to the decision makers, we need a common standard on how suitability maps should be derived. This tool as well as the underlying review help to guide the discussion and show advantages and disadvantages of the maps.