Green Ampt Infiltration for the Storage Nodes of SWMM 5

Introduction:  This set of blogs uses the 1000 year rainfall/runoff/hydraulics model that you can download at http://swmm2000.com/forum/topics/1000-year-simulation-with-rainfall-in-swmm-5 to show the inner workings of SWMM 5 and by extension InfoSWMM and H2oMap SWMM using a QA/QC version of SWMM 5 with extended graphics.   I always hope that seeing the inner workings of a SWMM 5 feature helps to understand the code, sensitivity and importance of a parameter.   It also helps show sometimes when a parameter is not important.   Continuing with the recent blogs on Green Ampt Infiltration, you can also simulate the infiltration and evaporation from a Storage node in SWMM 5

Discussion:  The infiltration and evaporation can be simulated in SWMM 5 using Green Ampt Infiltration:

1.       The three Green Ampt parameters are entered in the Storage Node Dialog
2.      The statistics for the whole run are shown in the Storage Node Summary Table for Volume, Percent Full and Percent Loss
3.      The Node Storage Graph for Infiltration varies with the time and the depth of the storage nodes along with the side area (based on the average depth over a time step) and the bottom area of the node.   In figure 2, Area0 is the bottom area and Area1 is the side area.

Figure 1.   Green Ampt Infiltration for the Storage Nodes of SWMM 5 for a 100 year Simulation

Figure 2.  The bottom and side area of a storage pond (Functional)