A new formula which was based upon the use of such meteorological parameters which were commonly observed at all places has been presented. The results of this formula give an estimate of evaporation contours for each month of the year, six-monthly and annual contours are plotted which are helpful to determine the order of the evaporation taking place from various sites in West Pakistan. The large amount of evaporation taking place from the existing storages or those in the planning stage is estimated. It is also stated that saving of this water by suitable means is most essential and it may be undertaken as soon as possible. (From Engng News, 1965, 10(1): 20).