A subbasin is an element that usually has no inflow and only one outflow. It is one of only two ways to produce flow in the basin model. Outflow is computed from meteorologic data by subtracting losses, transforming excess precipitation, and adding baseflow. Optionally the user can choose to include a canopy component to represent interception and evapotranspiration. It is also optional to include a surface component to represent water caught in surface depression storage. The subbasin can be used to model a wide range of catchment sizes.