Based on the principle of water bal

Based on the principle of water balance, the water production module determines the water production according to the input and output of water, which can be carried out directly on the ArcGIS grid layer, so as to quantify and spatialize the regional water production. The water production module simplifies the confluence process, and does not distinguish between soil flow, surface runoff and underground runoff, but assumes that the grid water production reaches the outlet through any of the above methods. The model takes the year as the time unit, does not consider the change of the year, and takes the grid unit for calculation. The temporal pattern of simulated surface runoff is not applicable to this model. Climate is one of the main factors affecting regional water yield change. The model can preliminarily analyze the contribution of climate change to regional water yield by controlling variables, but it cannot be used to explain the hydrological process.