About 92% of Bahrain is desert with periodic droughts and dust storms, the main natural hazards for Bahrainis. Environmental issues facing Bahrain include desertification resulting from the degradation of limited arable land, coastal degradation (damage to coastlines, coral reefs, and sea vegetation) resulting from oil spills and other discharges from large tankers, oil refineries, distribution stations, and illegal land reclamation at places such as Tubli Bay. The agricultural and domestic sectors' over-utilisation of the Dammam Aquifer, the principal aquifer in Bahrain, has led to its salinisation by adjacent brackish and saline water bodies. A hydrochemical study identified the locations of the sources of aquifer salinisation and delineated their areas of influence. The investigation indicates that the aquifer water quality is significantly modified as groundwater flows from the northwestern parts of Bahrain, where the aquifer receives its water by lateral underflow from eastern Saudi Arabia, to the southern and southeastern parts. Four types of salinisation of the aquifer are identified: brackish-water up-flow from the underlying brackish-water zones in north-central, western, and eastern regions; seawater intrusion in the eastern region; intrusion of sabkha water in the southwestern region; and irrigation return flow in a local area in the western region. Four alternatives for the management of groundwater quality that are available to the water authorities in Bahrain are discussed and their priority areas are proposed, based on the type and extent of each salinisation source, in addition to groundwater use in that area.