Application of multi-criteria decision making for groundwater potential mapping in Manabí, Ecuador

Groundwater is an essential reserve for comprehensive water resources management. Territories such as the Manabí Hydrographic Demarcation (MHD) in Ecuador have considerable water scarcity during dry periods due to low rainfall, which generates significant losses for the agriculture sector. This work aims to map groundwater potential (GWP) in the MHD using a methodological approach combining remote sensing, geographic information systems (GIS), and analytic hierarchy process (AHP) modeling to support sustainable water management strategies. For the identification and reduction of variables, the multi-objective optimization (MOO) approach was used as a heuristic reference. By applying the Pareto principle, the variables with the greatest influence on the model were selected for the development of the final adjusted map of the groundwater potential index (GWPI_F). The spatial effectiveness (SE) and predictability results based on the receiver operating characteristic (ROC) and area under the curve (AUC) revealed that the GWPI_F (AUC = 72%, SE = 91%) performed better than the initial map of the groundwater potential index (GWPI, AUC = 52%, SE = 83%). The GWPI_F map indicates that the Chone and Portoviejo River basins represent the areas with the highest GWP. The geomorphological, lithological and slope characteristics of the territory offer opportunities to establish nature-based solutions (NbS), such as water sowing and harvesting (WS&H), to manage water resources and conserve ecosystems. The integration of the GWPI_F map within water resource management is crucial since it functions as a visual and spatial resource proposing comprehensive and sustainable alternatives aligned with United Nations Sustainable Development Goals (SDGs) to solve socioeconomic problems in the MHD.