Integrated geophysical healthy assessment for eco development and coastal sustainability in Ras Gamila, Egypt

Arid coastal regions like Ras Gamila, Egypt, face pressing environmental challenges, including seawater intrusion, freshwater scarcity, and development pressures, which threaten their ecological and economic sustainability. This study bridges a critical research gap by developing an integrated framework that links subsurface geophysical stability with surface environmental conditions to guide eco-development. We employed a multi-method approach, combining vertical electrical sounding (VES), time-domain electromagnetic (TDEM) soundings, shallow seismic reflection, soil radon analysis, and spatial data from digital elevation models (DEMs), shoreline dynamics, and climatological factors. Our results delineate a critical freshwater-bearing Nubian sandstone aquifer (19-94 m thick, resistivity: 228-302.5 Ωm) and identify significant seawater intrusion (resistivity: 1.1-2.5 Ωm). A novel sustainability matrix, integrating these diverse datasets, classifies the region into three distinct zones: high-sustainability inland areas (35-45% of the region) suitable for immediate development, moderate-sustainability central zones (35-45%) requiring targeted improvements, and low-sustainability coastal areas (25-30%) necessitating restoration and protection. The findings provide a scalable, geophysically-informed model for sustainable planning in arid coasts, directly supporting United Nations Sustainable Development Goals (SDGs) 6 (Clean Water) and 13 (Climate Action) by offering a science-based strategy for balancing economic growth with environmental conservation.