Assessment of future urban water resources supply and demand for Jeddah City based on the WEAP model

Abstract

Jeddah City is expected to experience water supply stress due to rapid population growth and expansion of urban developments. This paper aims to assess the impact of possible water demand on Jeddah water resources in 2030 and to examine the effectiveness of desalinated water on future water demand. To facilitate the analyses, a scenario-based modeling is used in conjunction with Water Evaluation and Planning (WEAP) software to find the best combination of scenarios that meet future water demands. For each scenario, the water resource implications were compared to a 2017 baseline. The model enabled analyses of unmet water demands, water demand, supply delivered, and supply requirement for each scenario. The study identifies the year of unmet demand and calculates the reliability, resiliency, and vulnerability of the supply system. Results show that the gap between demand and supply will grow dramatically if current desalinated supply condition continues. An additional quantity of more than 504 MCM is needed in 2030 to satisfy water needs and development. The implementation of the leakage reduction measures proposed by the National Water Company (NWC) with the current desalinated water, in conjunction with the application of reuse of treated wastewater and water conservation practices, can decrease the unmet demands and deficits to levels lower than, or similar to, those occurred in the 2017 baseline. However, in all cases, these involvements will be insufficient to completely meet the demands of all demand zones. The results confirmed that the WEAP model can be applied to various operating policies towards decision support system for water resources management in Jeddah City.