Determining Rain Water Harvesting Potential at NUST- Islamabad

Abstract

National University of Science & Technology (NUST) Islamabad campus spends millions per annum to meet its daily water needs, which includes drinking, washing, sanitation, laboratory uses, gardening etc. Water shortage at NUST is a cropping-up issue. Hence, the NUST management has already approved a project of Wastewater treatment, as a renewable source of water for lawn irrigation etc. The main objectives of the current study were “Determining the Rainwater Harvesting (RWH) Potential at NUST” and to "Analyze the collected rain water quality for Physical, Chemical and Biological parameters, in order to determine its reuse potential as drinking water". Islamabad receives more than 1100 mm average annual rainfall. To calculate the overall potential of RWH, a model roof-top rainwater harvesting system was installed at IESENUST, whereas infiltration tests were carried out at the open areas to calculate the runoff potential of local soil. The collected rain water was analyzed at IESE laboratory. The overall results were found very encouraging, except biological contamination, which was mainly due to birds dropping at the roof-top of the selected building. Whereas, introduction of First Flush Diverter (FFD) was found very helpful as a simple method of removing the physical impurities. The study demonstrated that a total of 577 million gallons/year or 1.55 MGD of rainwater can be harvested from the NUST campus Islamabad, which clearly indicates a high potential for RWH, not only in the NUST but surrounding areas of Islamabad, Rawalpindi and adjacent Pothohar region as well. Hence, the use of rainwater is deemed essential for addressing the water scarcity and management issues in line with the future requirements of “Climate Change Adaptation” and to provide sustainable, affordable, alternative and supplementary solution in a most decentralized way.