ABSTRACT
Demand for water has been rising for much of the twentieth century, at different rates in different parts. We saw in Chapter 1 that there is a quite variable relationship between rates of withdrawal of water from available supplies and rates of water consumption (e.g. by individual households, industries or cities). This suggests scope for managing water in ways other than always seeking to increase supply. The earth contains vast quantities of water but high intensity of demand, for example in large cities, will, as we saw in Chapter 2, inevitably outstrip local water sources that are readily available. Thereafter, further supply must be achieved from more distant sources or by using more sophisticated technology. In Chapter 5 we reviewed different ways of engineering larger supplies of water and concluded that more water can invariably be obtained, but at a rising cost.
