Introduction

For the vast majority of human activities – be that domestic, industrial, or agricultural – we require fresh water. It is a resource often taken for granted in more economically developed countries; people assume that fresh water will be available when the tap is turned on, and like electricity do not question the processes or constraints involved in delivering it. However for many people in the world, easily available fresh water is not the case, and finding clean fresh water for drinking, cleaning and growing plants is a serious challenge. The fresh water systems of the planet are under threat from climate change, unsustainable use and pollution.

Engineers have a role in providing the infrastructure to supply water to the world's population. Andrew Mylius (2000) stated “The engineers that help realise the water supply opportunities will be this century’s most valued peace keepers. Competition for scarce water resources is increasingly a source of political tension. Engineering can play a major role in defusing it.” [see reference 1]

The image we have of the Earth as the ‘Blue Planet’ is slightly misleading when we consider the water available for our use. Most of the Earth is covered by seas and oceans accounting for over 97% of total water on the planet, leaving less than 3% of the planet’s water that is not salty (potable). Of the freshwater that is present, 2 percent is locked in icecaps and glaciers, and a large proportion of the remaining 1 percent lies too far underground to exploit” [See reference 2]

Global Water Volumes:

Total volume = 1.40 billion cubic kilometres

Freshwater = 35 million cubic kilometres (less than 3% of all water)

Usable freshwater approx. 200,000 cubic kilometres (less than 1% of freshwater) [see reference 3]

This chapter will outline the problems facing the world today in terms of water. Water supply and water scarcity of nations worldwide will be highlighted, introducing the term “water debt”. We will look in detail at what the global uses of water are, desalination, water pollution before finally looking at international standards for water supply and distribution.

image sourced from Gaia Health under a Creative Commons Attribution-ShareAlike 3.0 Unported License
http://gaia-health.com/gaia-blog/2011-11-18/eu-says-bottled-water-doesnt-treat-dehydration-the-scientification-of-drinking-water/