SWMM5, InfoSWMM

Subject:  WARNING 04: minimum elevation drop used for Conduit  - What Does this Message Mean?

This message means that the elevation drop across the link  is less than the minimum allowable drop or (0.001 /3.048 meters)

Elevation1 = Link Offset Upstream + Upstream Node Invert

Elevation2 = Link Offset Downstream + Downstream Node Invert

Internally Elevation1 – Elevation2 should be greater than 0.001 /3.048 meters.  If it is not then SWMM 5 or InfoSWMM will use the minimum drop or 0.001 /3.048 meters

It simply is a rule that does not allow flat slopes as the flat slopes mean no normal flow calculations. You should not have to worry about this warning message.

Here is an example of a conduit in which the rule is applied.  The rule is applied to link U-104 because it is flat and has no slope.

Subject:  How to Make an Internal Outfall into an External Outfall when you have more than one link connected to an Outfall

  Step 1:  Identify the Problem “ERROR 141: Outfall J-561 has more than 1 inlet link or an outlet link.” Means you have an outfall node in the middle of your model.

Step 2:  Make a new outfall.

Step 3:  Make the new Outfall  have the same invert as the old outfall

Step 4:  Convert the older outfall  to a Junction using the Pick Axe and the Convert Type tool

 Step 5:  Make a new Link connecting the old and the new Outfall

 Step 6:  Convert the new Link to an  Outlet Type using the Convert Type Tool.

 Step 7:  Set up the parameters for the new Outlet Link

Step 8:  For those outfalls that DO have more than one link you need to make a new Outfall.

  You should be able to run the model now

Note: Steps to take and rules for Cloning Datasets in InfoSWMM and InfoSewer

 Before cloning an active dataset, the user should switch to the Base Scenario.  This saves the active datasets and allows the user to clone the dataset with all edits. 

This is a brief description of how datasets are created and saved. 

·         Any data the user changes are only changed in the Active data sets while the user is working in a given scenario. 

·         The modified data are not saved into the selected custom data sets until the user selects different data sets—either by selecting a new scenario or by using the Edit Active Scenario command. 

If the user changes to a new scenario that shares some of the same data sets (e.g. same pipe, valve and pump data sets), the data in these common data sets are still not updated (saved) by changing scenarios.  The user has to actually select a different custom data set of the same type to get the data to update in the custom data set (e.g. the user must select a different pipe set to get the modified pipe data to save into the selected pipe set).  Once created, a dataset is not updated (saved) until it is no longer in use by the active scenario. 

In addition, there is a fundamental difference in between BASE dataset and other dataset(s). 

·         The other dataset(s) must be explicitly created first before they can be used. 

·         BASE dataset will "never" exist until it is switched off from the active scenario. 

·         It gets implicitly created at the first time when it is released from the active scenario.  That is why BASE dataset is never found in a "new" project which has only a base scenario.

Subject:  Wikipedia Traffic for the SWMM versus EPANET Articles

Wikipedia has one article for EPANET and three articles for SWMM 5 (two are redirected to the Stormwater Management Model Main Article).  The statistics for the last three years (data before 2007 is unavailable) show an average of 28 visitors per day to SWMM and 16 per day to EPANET).  The most common search name has switched from the word SWMM to Stormwater Management Model starting in 2009.

Note:  How to change the Maximum Infiltration in a DB Table of InfoSWMM and H2OMAP SWMM

 There are a lot of methods in InfoSWMM and H20MAP SWMM to change the infiltration data.  You have the ability to change it for

 1.      an individual subcatchment using the Attribute Browser

2.      by soil type and

3.      the coverage of the soil over all of the subcatchments – this will alter the areal weighted average of the infiltration data

 You have layers of infiltration data in the interface to your model data.  The infiltration parameters are defined per soil as in a real watershed and the subcatchments will use the areal weighted infiltration values of all of the soils on the subcatchment.  You get more flexibility and closer to the physical reality of the subcatchment by having layers of soil on the subcatchment rather than one set of infiltration per subcatchment.  Of course if you set up one soil type per subcatchment then you will have 100 percent coverage of the same infiltration set of parameters per subcatchment.

 Method 1: An Individual Subcatchment by using the Attribute Browser

Method 2: All of the Infiltration Data in the Soil Tables using the DB Editor and the Block Edit command.

Method 3:  You can also change the overall Infiltration by changing the soil coverage of the Subcatchment using the Subcatchment Infiltration table.