Accidental pollution spills have significant impacts on Water Treatment Plants (WTPs), which frequently require temporary closures to protect public health. While research on the Nile River in Egypt has focused on evaluating overall water quality, relatively few studies have simulated spill accidents and their impacts on water treatment plants. This research fills the gap by modeling phosphate spill scenarios and examining the effects of phosphate spills on water treatment plants (WTPs) along the Nile River Reach Four, including the Deer-Alkaseer, Dairout, and Deir-Mawas WTPs. The Delft3D model was used to simulate hydrodynamic and water quality scenarios under both minimum and maximum flow conditions. The results were calibrated by comparing them with data from gauge and monitoring stations to ensure accuracy. Multiple phosphate spill scenarios were simulated in front of the Deer-Alkaseer with varying spill amounts and durations. The results revealed that spill concentration and duration significantly affect plume characteristics such as concentration levels, time to peak, and travel time. Extended spills with low concentrations resulted in minimal contamination, maintaining them under regulatory thresholds and indicating that shutting down the WTPs would not be necessary. These events can be detected using real-time monitoring systems with water quality sensors. The duration of the spill and flow conditions significantly influenced the time to peak concentration, regardless of the spill concentration. Plume duration increased with higher spill concentrations and longer durations, particularly under minimum flow conditions. Spill scenarios can support a smart dashboard using spill scenarios data to help tiered operational plans for WTPs.