OPTIMAL RAINWATER HARVESTING TANK SIZING FOR DIFFERENT TYPES OF RESIDENTIAL HOUSES : PILOT STUDY IN KUCHING, SARAWAK

• Main Authors: Kuok, King Kuok, Chiu, Po Chan
• Format: Article
• Language: English
• Published: School of Engineering, Taylor’s University 2022
• Subjects: QA75 Electronic computers. Computer science
• Online Access: http://ir.unimas.my/id/eprint/46914/1/15_1_392.pdf; http://ir.unimas.my/id/eprint/46914/; https://jestec.taylors.edu.my/Vol%2015%20issue%201%20February%202020/15_1_39.pdf

This study investigated the potential of installing rainwater harvesting system (RWHS) for non-potable water uses of single-storey residential houses including terraced intermediate, terraced corner, semi-detached and detached houses. The selected study area in Kuching, Sarawak, Malaysia. The analysis was carried out using daily Mass Balance model and cross-checked with Tangki NAHRIM software. Input data are 10 years daily rainfall, which observed data from years 2011 to 2017 are collected from Department of Irrigation and Drainage (DID) Sarawak, and rainfall data from years 2018 to 2020 were forecasted by Statistical Downscaling Model (SDSM). Results show that RWHS is able to supply about 40% of the total monthly household water usage. Optimum tank size for terraced intermediate, terraced corner, semi-detached and detached was found to be 2.00 m3, 2.00 m3, 2.05 m3 and 2.10 m3 respectively. Payback analysis revealed that the installation cost can be recovered within 6 to 8 years. With the current water rate of RM0.76/m3 charged by Kuching Water Board, it is highly unlikely that RWHS is able to confer financial savings. However, RWHS should be installed as an alternative water supply source to satisfy growing water demands, reduce runoff peak and volume and achieve sustainable water usage practice in Kuching and its surrounding areas.