Framework for identifying large-scale Nature-Based Solutions for drought mitigation: regional application in Flanders 

Abstract

Droughts are classified as the most expensive climate disasters as they leave long-term and chronic impacts on the ecosystem, agriculture, and human society. The frequency, intensity, and duration of drought events have shown a historical increase and are projected to escalate globally, continentally, and regionally in the future. Nature-based solutions (NBS) are highlighted as effective solutions to cope with the future impacts of these events. Until now, there has been a lack of a comprehensive suitability mapping framework that considers drought-specific criteria. To address this gap, a novel framework is introduced, targeting the identification of suitable areas for two drought-mitigating NBS types—detention basins and managed aquifer recharge—on a regional scale.  This new framework incorporates diverse criteria to specifically address drought conditions. For example, by incorporating climate change scenarios for both surface and groundwater, it identifies suitable and sustainable locations capable of managing extreme drought events. Executed through Boolean logic at a regional scale in Flanders (Belgium), the framework's strict approach yields significant potential areas for detention basins (298.7 km²) and managed aquifer recharge (867.5 km²). Incorporating multi-criteria decision-making (MCDM) with the same criteria introduces a higher degree of flexibility for decision-makers. This approach shows a notable expansion across Flanders, varying with the level of suitability. The results underscore the highly suitable potential for detention basins (2840.2 km²) and managed aquifer recharge (2538,7 km²), emphasizing the adaptability and scalability of the framework for addressing drought in the region.