How to Define Green Ampt Infiltration in ICM

Here are the steps to make a Subcatchment with Green Ampt Infiltration in ICM:

1.       You use the Subcatchment, Land Use and Runoff Surface Tabs in the Subcatchment Grid (Bullet 1)
2.      The Subcatchment Tab has three Runoff Areas for Impervious with Depression Storage or Initial Loss, Impervious with no Initial Loss and Pervious Area (Bullet 2)
3.      The Runoff Surface percentages on the Subcatchment are connected to the Land Use Tab by the Land Use ID, in this example we are using Runoff Surfaces 22, 23 and 24 (Bullet 3)
4.      The Runoff Tab defines the Runoff Surfaces defined in the Subcatchment Tab and Land Use Tab (Bullet 4)
5.      You can define the Routing Model per Runoff Surface or SWMM in this case (Bullet 5)
6.      The type of Runoff Surface and Surface Type for each Runoff Surface or GreenAmpt for Runoff Surface ID of 24 (Bullet 6)
7.      The Depression Storage or Initial Loss Value for each Runoff Surface in the Runoff Surface Tab (Bullet 7)
8.     The Green Ampt Infiltration Parameters are defined to the right in the Runoff Surfaces Tab (Bullet 8)

a.      Suction in inches or millimeters

b.      Saturated Hydraulic Conductivity in inches/hour or mm/hour

c.       Deficit as a fraction

  

Figure 1.  Steps in defining Green Ampt Infiltration for ICM