M. MONDOL1, B. DHAR2, M. RAHMAN3, J. DHAR4 and I. SAHA5
1= M. Mithun Mondol, Khulna University of Engineering and Technology, Khulna, 2Bishwajit Dhar, Jessore University of Science and Technology, Jessore, 3Moshiur Rahman, Khulna University of Engineering and Technology, Khulna, 4Jyotirmoy Dhar, Rajshahi University of Engineering and Technology, Rajshahi and 5Indrajit Saha, Rajshahi University of Engineering and Technology, Rajshahi, Bangladesh.
ABSTRACT
The study was carried out at the Department of Civil Engineering, Khulna University of Engineering and Technology (KUET), Khulna Bangladesh during March 2010 to April 2011 to explore the opportunities and possibilities of utilizing rainwater harvesting as a secondary resource. All the collected data was analyzed at the Computer Laboratory, Department of Civil Engineering in KUET. As 97% of the supply water comes from groundwater, a search for alternative water sources is critical. This study identified and analyzed different purposes of rainwater harvesting; studies the importance of rainwater harvesting in the urban areas of Khulna. The study investigated the rainwater collected on a six-storied residential building with 50 persons residing in the building. In performing the study, storage volume was determined on an annual rainfall data from Bangladesh Meteorological Department (BMD) of Khulna. Mass curve analysis was used to determine required storage volumes; design curves were developed for estimation of storage volumes covering the need for drinking or domestic purpose. This study found that enough rainfall for harvesting which can satisfy the drinking water requirements in liter per capita per day (Icpd) (3 Ipcd). Cumulative distribution showed that maximum excess water of 162.394 m2 is available during October and maximum deficit occurs during the month of April, 11.372m3. For full utilization of rainwater potential, a storage tank of capacity 173.766 m3 is required. It was found that the reliability for the studied period ranges from 16.19% to 100%. The average reliability was found to be 87% (3 Ipcd), not satisfactory for domestic purpose (80 Ipcd). Cumulative distribution showed that maximum deficit occurs at 1200m3. It was found that the reliability for the studied period ranges from 0.61% to 39.93%. The average reliability was found to be 17.9 % (80 Ipcd). From Khulna City Corporation (KCC) and rainwater source it has been found that, it can satisfy the demand of 56.46 % for domestic purpose.
Keywords: Rainwater harvesting, Storage volume, Domestic purpose and Water supply.