Salinization in large river deltas: Drivers, impacts and socio-hydrological feedbacks

Salinization of freshwater and soils is a global phenomenon that adversely affects 500 million people, particularly in low-lying river deltas. Impacts of salinity on food and water security and agricultural livelihoods are well documented and reviewed herein, along with additional effects on human health that have received less attention and warrant further study. Populations forced to consume saline waters display increased occurrence of diseases such as hypertension in Bangladesh, particularly among the rural poor in coastal areas. This review synthesizes knowledge on socio-hydrological drivers of salinization in large river deltas globally. Multiple drivers arise at different scales and include agricultural practices, upstream water diversion, and relative sea level rise and can be amplified through feedback from inappropriate adaptation strategies. Understanding deltas as truly coupled socio-hydrologic systems is critical to anticipate these feedbacks.