Desalinated Seawater for Phosphate Processing as a Key to Maintainingthe Sustainability of the Mountain Oases of Tamerza, Chebika, and Mides in Southwestern Tunisia

Abstract

The mountain oases of Tamerza, Chebika, and Mides in southwestern Tunisia rely on perennial springs fed by fossil groundwater from the Continental Intercalaire and Complex Terminal aquifers, including the Miocene Beglia Formation, which support both traditional gravity irrigation and high-value Deglet Nour date production. Since the 1950s, extensive groundwater abstraction for phosphate extraction and washing in the Moularès–Redeyef basin, along with agricultural expansion and climate-driven aridification, has caused a significant decline in piezometric levels, spring discharge, and water quality, accelerating soil salinization, biodiversity loss, and the emergence of new date palm pests. This work argues that a strategic, large-scale shift from fossil groundwater to desalinated seawater for mining and industrial uses is the most effective solution to reduce pressure on the aquifers that supply the oases, thereby preserving natural springs and the ecological services they provide.