Rainwater Harvesting-an alternative water supply in the Future for Pakistan
By: Ishtiaq Hassan
Key Words: Potable, non-potable, rainwater harvesting, SamSam, roof.
J. Bio. Env. Sci. 8(6), 213-222, June 2016.
Availability of potable water is the major issue in countries like Pakistan. The problem has aggravated due to more population density and least permeable surfaces. Thirty year rainfall data obtained from Meteorological Department of Islamabad for the study areas of Rawalpindi and Lahore has been used to validate the inbuilt rainfall data of SamSam Rainwater Harvesting Model. The model worked out storage reservoirs for flat roof sizes of 110 m2, 220 m2, 280 m2 and 400 m2 with dwellers of 2, 4 and 8 number. To meet 45% needs of non-potable water demands, in areas with appreciable rainfall, the minimum suggested roof size is 220 m2 for single family (4 persons) and 400 m2 for two family units (8 persons). On the other hand, for areas with lesser rainfall, the minimum suggested size is 280 m2 for single family and 400 m2 for two family units. Implementation of such measures will help saving of 45% (almost half) of potable water.