Clean water is vital to life, it is essential for human survival. Freshwater accounts for
only 2.5% of the total water on the planet, much of which is unavailable due to being locked up in glaciers and ice caps (Shiklomanov 1999). Usable fresh surface water in the
form of lakes and rivers accounts for only 0.3% of the total freshwater on the planet
(Figure 1-1) (Shiklomanov 1999). It is essential to conserve and protect this very limited
and precious natural resource.