How is the Soil Saturated Conductivity Used in SWMM 5 Green-Ampt?

Subject:   How is the Soil Saturated Conductivity Used in SWMM 5 Green-Ampt?

How sensitive is the infiltration loss and rate to the Soil Saturated Conductivity parameter in the SWMM 5 Green-Ampt  infiltration method.   Figure 2 shows how the total infiltration loss and total loss rate vary as you change the soil saturated conductivity from 1 to 0.1 to 0.01 inches/hour.  Internally, Ks is used to check saturation and in the computation of the soil infiltration rate. Two of the checks are:

·         In low rainfall everything infiltrates as irate less than Infil>Ks and
·         In the check to see if the soil is already saturated. 

 

Figure 1.  The three parameters for Green-Ampt Infiltration in SWMM 5

Figure 2.  The sensitivity of the total infiltration loss to the soil saturated conductivity in a continuous simulation