Figure 1. The Internal Green Ampt Parameters, Soil Moisture and IMD for a 100 Year SWMM 5 Simulation for Green Ampt Infiltration
Sunday, December 29, 2013
The Internal Green Ampt Parameters, Soil Moisture and IMD for a 100 Year SWMM 5 Simulation for Green Ampt Infiltration
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. In this example, we show some of the internal working of the Green Ampt Infiltration Parameters over the 100 year period.
Discussion: Key internal parameters for Green Ampt infiltration are
FUMax is the Saturated Moisture Content of the Upper Zone (internal units of feet)
F or FTOT in the graph is the Cumulative event infiltration at start of time interval (internal units of feet)
FU is the current moisture content of upper zone (internal units of feet)
As shown in Figure 1, IMD and Soil Moisture are related. When the soil moisture is zero then the IMD is equal to the maximum values of IMD or IMDMax.
These three parameters are used to calculate the IMD during the simulation among other important uses
IMD = [ Maximum Allowable Infiltration – Current Moisture Content of the Upper Zone ] / Depth of the Upper Soil Layer
Or IMD = [ FUMax – FU ] / Depth of the Upper Soil Layer
Soil Moisture = IMDMax - IMD
Culvert inlets and outlets To improve the process of defining culvert inlet and culvert outlet losses for an InfoWorks network, a new fiel...
@Innovyze User forum where you can ask questions about our Water and Wastewater Products http://t.co/dwgCOo3fSP pic.twitter.com/R0QKG2dv...
Engine Error Number Description ERROR 101: memory allocation error. ...
Subject: Manhole Elevations in InfoSWMM and SWMM 5 Starting from the bottom of the manhole you have these regions of compu...