Areal Depletion

Areal depletion refers to the tendency of accumulated snow to melt non-uniformly over the surface of a subcatchment. As the melting process proceeds, the area covered by snow gets reduced. This behavior is described by an Areal Depletion Curve that plots the fraction of the total area that remains snow covered against the ratio of the actual snow depth to the depth at which there is 100% snow cover. A typical ADC for a natural area is shown in Fig. 50. Two such curves can be supplied to GeoSWMM, one for impervious areas and another for pervious areas.

Fig.50: Areal Depletion for a natural area (Source: User Manual for EPA-SWMM 5.1)