SWM is the earliest and most famous watershed hydrological model. It is a deterministic model that uses mathematical methods to simulate hydrological and physical phenomena.
Stanford model is based on water balance:
1. Four aquifers: upper soil layer accumulation, lower soil layer accumulation, groundwater (shallow) accumulation and deep groundwater accumulation. The flow detention in soil and slope are only temporary accumulation.
2. The runoff sources in the model include direct runoff on impervious area, overland flow on slope surface, flow in soil and shallow groundwater.
3. Evapotranspiration sources: snowmelt accumulation; interception accumulation; upper soil layer accumulation; I lower soil layer accumulation; groundwater accumulation; river and lake surface.
4. The model is a continuous calculation model. The calculation period should not be too long, otherwise, the physical processes in the period will change too much. Swmiv was calculated in 15 minutes or 1 hour.