Water in the life of human beings is like a two sided medallion. In one side of the medallion the demand for water lies which includes domestic, industrial, agricultural and recreational use of water resources. The better these demands are satisfied, the better a life on earth will a human being has. The problem about the first side of the medallion is that water is not always available in the desired quantity (e.g. droughts) and quality (e.g. pollutants). In the other side of the medallion, the undesired abundance of water (floods) lies. The problem about the second side of the medallion is...