Node Time Step in SWWM 5

Subject:  Node Time Step in SWWM 5
The node time step in SWMM 5 is based on the maximum depth of the node, the last time step and the change in depth at the node between the current time step and the last time step.  It is calculated at the beginning of each time step in the dynamic wave solution of SWMM 5.  The maximum depth is the difference between the crown elevation of the node and the invert of the node. It is normally much less than the link  time step in SWMM 5 and is only important at the beginning of the simulation when the depth between the current node depth and the old node is large (Figure 1).  This is especially true if a hot start file is not used and the node starts out empty.   If the node time step is smaller than the link time steps it will be listed in the Table Time Step Critical elements (Figure 2).
Figure 1.  Equations for the Node Time Step.
Figure 2.  Node Time Step is critical at the beginning of the simulation.

Components of the global water cycle

 

Components of the global water cycle

Feb 21, 2011 to Mapping | http://flowingdata.com/2011/02/21/components-of-the-global-water-cycle/
"NASA briefly explains the water cycle:
Water regulates climate, predominately storing heat during the day and releasing it at night. Water in the ocean and atmosphere carry heat from the tropics to the poles. The process by which water moves around the earth, from the ocean, to the atmosphere, to the land and back to the ocean is called the water cycle.
The three animations above show hourly evaporation, water vapor, and precipitation, based on "data from the GEOS-5 atmospheric model on the cubed-sphere, run at 14-km global resolution for 25-days." I'm not even going to pretend like I know what I'm talking about, but it is fun to watch the simulated global water movements. Remember, these are based on actual data. They are not closeups of lava lamps."

How to Calculate the Freeboard of a Node in InfoSWMM/H2OMAP SWMM

Note:   How to Calculate the Freeboard of a Node in InfoSWMM/H2OMAP SWMM from the Model Results

 

The freeboard for a node in InfoSWMM/H2OMAP SWMM can be calculated with a 4 step process:

 

1.   Copy the Node Rim Elevations from the DB Tables for Junctions to Excel,

2.   Run the model and then copy the Maximum HGL from the Junction Summary output table to Excel,

3.   Calculate the Freeboard in Excel as the Rim Elevation minus the Maximum HGL in Excel,

4.   Create a new column called Freeboard in the Junction Information DB Table and paste the Freeboard from Excel.

 

You will be able to perform Map Displays or Map Queries now using the new Freeboard information column.

Figure 1.  4  Step Process to Calculate Freeboard

Steps in converting a Arc GIS 10 Model to a Arc GIS 9.3 Model in InfoSWMM or InfoSewer

Note:  Steps in converting a Arc GIS 10 Model to a Arc GIS 9.3 Model in InfoSWMM or InfoSewer

Step 1.  Make an empty Arc GIS 9.3 model in InfoSWMM using the Arc GIS Default when initializing the model,

Step 2.  Save the empty model and then copy and paste the files from the Arc GIS 10 ISDB folder to the Arc GIS 9.3 folder, but not the MAP sub directory,

Step 3.  Open the Arc GIS 9.3 mxd file and then use the Tool Update Map from DB after Initialization,

Step 4.  Zoom to the model extents and then set data frame to the model view so it can be used more efficiently in the future before saving the model.