The researchers wanted to improve water quality in the Shiyan, Tiegang, and Xili Reservoirs in Shenzhen, China, which provide drinking water. They used a computer model to understand how water quality changes over time in these reservoirs. The model accurately predicted water levels and pollution levels like CODMn and TN. The best ways to improve water quality were identified: reduce the amount of polluted water coming into the Shiyan Reservoir, decrease the transferred dirty water in the Tiegang Reservoir, and increase clean water flow in the Xili Reservoir during floods. Removing sediment regularly is also important to prevent internal water pollution. This information can help protect the drinking water sources in Shenzhen and improve water quality management overall.