Development of dual water supply using rainwater harvesting and groundwater systems

• Main Author: Ayob, Syafiqa
• Format: Thesis
• Language: English; English; English
• Published: 2018
• Subjects: TD201-500 Water supply for domestic and industrial purposes
• Online Access: http://eprints.uthm.edu.my/361/1/24p%20SYAFIQA%20AYOB.pdf; http://eprints.uthm.edu.my/361/2/SYAFIQA%20AYOB%20COPYRIGHT%20DECLARATION.pdf; http://eprints.uthm.edu.my/361/3/SYAFIQA%20AYOB%20WATERMARK.pdf; http://eprints.uthm.edu.my/361/

Demand on water resources has been rapidly increasing and the issue of supplying adequate water to meet societal needs is one of the most significant challenges faced by the provider. Therefore, there is a need to utilise the limited amount of water resources available in a more efficient way. The overall aim of this study was to gain a better understanding on dual water supply system consisting of rainwater and groundwater. The pilot study of the designed system was carried out at the Universiti Tun Hussein Onn Malaysia, Batu Pahat, Johor. The data collection was conducted between December 2016 and May 2017 which covers both wet and dry seasons in the study area. For rainwater harvesting (RWH) system, five (5) components namely roof catchment, gutters, down pipe, first flush diverter, and storage tank were successfully designed. Meanwhile, groundwater was pumped from an existing tubewell. Both harvested rainwater and groundwater were then stored in a distribution tank. The first part of the analysis was carried out to assess the RWH efficiency. The monthly results on total volume of collected rainfall in storage tank was 48.97 m3 while the actual rainfall calculated was 56.04 m3 with 75% of collection efficiency. A rainfall–storage rating curve was then plotted using 150 rain events data versus the volume of harvested rainwater collected within the study period. The second part of the analysis was to determine the groundwater transmissivity (T), hydraulic conductivity (K) and the water well yield by conducting a step drawdown and constant pumping tests. Electrical resistivity method (ERM) was first conducted to determine the depth of the existing tubewell. The results showed that the depth of the well was 20 m. Transmissivity (T) and hydraulic conductivity (K) values were 1.45 m2/d and 0.0725 m/hr, respectively. Meanwhile for daily discharge rate, the well was capable to supply water approximately 1.69 m3. In the current study, the daily water demand was 0.59 m3, which gave the total volume per month approximately from 16.5 m3 to 18.3 m3. Based on the performance of the system, most of the days rainwater could not meet the water demand, thus have to be supported by the groundwater. Rainwater Harvesting and Groundwater system (RHaGs) calculator was then developed from the generated rainfall–storage rating curve equation. By using the calculator, users can estimate the total volume of rainwater that can be collected and the amount of groundwater needed to cater the water demand. Overall, it can be concluded that dual water supply using rainwater and groundwater systems will contribute to a sustainability and environmental friendly method for restoring and conserving the natural water sources.