ABSTRACT
Ever since mankind ceased to survive entirely on hunting and foraging and started farming, the supply of water has been of major concern. The earliest diversions and control of water would have been for supplementary irrigation, for man and beast. With the growth of population, particularly in the warmer regions, irrigation became more and more important. Over the last few centuries the World’s population has increased rapidly and the demand for water even more. The needs for man and beast for industrial uses for irrigation and for cooling water demands in some areas exceed the available amounts. The various uses, as well as that for hydro-power, lead to conflicts between environmental and recreational requirements. A particularly serious problem is the contamination of various sources of water. Many industrial and domestic users require special treatment and quality control of water.
