Due to natural and anthropogenic causes fresh water supplies around the world are threatened, reducing fresh water availability required for any human activity. In delta areas the problem is exacerbated by rising sea levels which threatens fresh water resources through salt water intrusion. This research provides tools through which industry, agriculture and governments can cope, and even thrive, in the face of this challenge. The research examines the current situation, available technologies, and possible future technological developments to ensure an adequate water supply. In this research `salt water is no longer seen as a threat but as an opportunity: saline water where possible, freshwater where essential.