The Liangjiang hydropower station is in an area with lots of rain, and the amount of water flowing in the river mainly depends on how wet the soil is and how much rain falls. The way water flows in this area is best predicted using a rainfall-runoff forecast method. The researchers figured out how to calculate the factors that affect rainfall turning into runoff, and made a diagram to show how they are related. They also explained the steps to forecast how much runoff will happen based on rainfall.