Development of a Sustainable Water Supply through Combined Rooftop Rainwater Harvesting and Groundwater System

Increased population often leads to water supply deficit as the demand for water rises. In water resource, rainwater harvesting (RWH) holds great potential for providing a sustainable water supply in Malaysia, while groundwater serves as an alternative water source especially in limited surface water places. This study aims to evaluate the feasibility of sustainable water supply system that combines RWH and groundwater. The first objective is to design an integrated RWH and groundwater extraction to meet the required water demand. The second objective is to evaluate the groundwater quality index on the groundwater based on Malaysia's National Water Quality Standards. This study was conducted at UiTM Kampus Jengka, Pahang. The first step of the methodology involves evaluating the efficiency of the rainwater harvesting system by comparing monthly rainfall from April to September 2024 against the volume of harvested rainwater. In general, volume of shortfall in rainwater supply in UiTM Jengka is about 5m3 per month. In this study, volume of monthly harvested rainwater ranges from 2.74m3 to 4.25m3. The second step was to identify volume of water needed for landscaping purposes around campus of UiTM Jengka which is about 6.3m3 per month. Finally, the water quality index was assessed through laboratory testing of the groundwater sample, using four different types of treatment. This process could evaluate the suitability of the groundwater for consumption and guide on future treatment processes for more efficient use. It is found that the harvested rainwater was not sufficient to meet the area's water demand on most days for landscaping purpose, necessitating reliance on groundwater. Moreover, the water quality index for groundwater was only complied with the required standards for non-potable uses, such as general cleaning, livestock consumption, and landscaping. It is recommended that the groundwater undergo additional treatment, particularly for the removal of heavy metals, to ensure consumer safety.