Cascading vulnerability scenarios in the management of groundwater depletion and salinization in semi-arid areas

Meteorological droughts can have unexpected cascading consequences on social, economic, and environmental systems, which depend on the starting conditions of affected systems, and on natural and human drivers. In coastal areas, droughts propagate their effects to coastal aquifers, causing exacerbation of withdrawals with consequent worsening of groundwater quality and quantity. Considering the area of Lecce province (Salento peninsula, Apulia region, Southern Italy), the study outlines the non-linear cascading paths related to groundwater depletion and salinization in an urbanized coastal region depending quite entirely on groundwater resources of a coastal karst aquifer. The outline of cascading events is the outcome of a scenario building process carried out through semi-structured interviews to water management stakeholders. The cascading scenarios relate to different degrees of system resilience and describe chain effects and vulnerabilities. These scenarios can have significant outcomes in improving water management practices and increasing both local manager and end-user awareness about potential and unexpected cascading consequences related to droughts.