Abstract:
Traditional urban water supply schemes cannot meet the demands of the ever increasing population therefore an alternative water source need to be explored to supplement the existing urban water supply. This study was designed with the objectives to a) quantify urban storm water runoff using Environmental Protection Agency’s (EPA) storm water management model (SWMM) and 2) locate storm water harvesting sites using GIS and remote sensing techniques. This study basically deals with the calculation of rainfall discharge by using traditional but most effective method i.e. Rational formula method, quantifying rainfall runoff by SWMM and rain water harvesting sites of the Islamabad by applying guidelines of IMSD on the various thematic maps that were prepared in GIS and RS environment, e.g. slope, soil, runoff potential and land cover maps. ASTER satellite data has been effectively used for classifying land cover types of the study area, the multi criteria analysis of GIS provided an accurate and time effective platform for the study. Identification of potential sites for rain water harvesting is a significant step towards maximizing water availability and reducing water related issues. SWMM provides a powerful tool for completing rainfall runoff because of its fast convergence and graphical user interface capabilities. The result showed that the Rational formula method results revealed that maximum rainfall discharge 541.826 m3 /y and minimum rainfall discharge 48.3477 m3 /y, according to IMSD result for rainwater harvesting structures, have been suggested for Islamabad i.e., 19 percolation tanks, 3 farm ponds and 13 bundies. SWMM quantified the surface runoff result in volume acre-feet of Islamabad urban area. It is recommended that RWH techniques by using IMSD guidelines should be applied to similar terrain conditions with some local considerations.
