Integrated Urban Water Modelling for South African Water Services

Water is central to nearly all municipal functions, including potable supply, wastewater collection and treatment, stormwater management, environmental protection, and revenue collection. However, in South Africa, these functions are often managed independently, leading to inefficiencies and fragmented decision-making. This position paper emphasises the importance of Integrated Urban Water Modelling (IUWM), particularly through Integrated Urban Water System (IUWS) models that incorporate sub-models for rainfall-runoff, sewer networks, wastewater treatment plants, and river water quality. Such models enable a holistic understanding of interactions between subsystems, thereby identifying leverage points where interventions can maximise system-wide benefits. IUWM tools serve as powerful decision support systems, providing data essential for long-term planning, sustainable management, and resilience of urban water systems.