The following canopy methods are included within HEC-HMS:
Dynamic Canopy
Simple Canopy
With each method, canopy interception is found for each computation time interval and is then subtracted from the precipitation depth for that interval. The remaining depth is referred to as canopy overflow. This depth is considered uniformly distributed over a subbasin or grid cell, depending upon the chosen method, so it represents a volume of runoff. This runoff volume is then passed onto the surface and/or loss (infiltration) methods.