Orifice Open and Close Speed and the Target Setting

Orifice Open and Close Speed and the Target Setting

In SWMM 5 there is an orifice parameter called setting which opens or closes the orifice opening by modifying the depth of the orifice.  The setting is  based either on a RTC rule of the orifice or the Flap Gate condition of the orifice and can be between 0 and 1.  Closed is 0; Open is 1.  The difference is that the target setting is what the setting should be based on the condition of the Flap Gate or the RTC Rules and the setting is the value actually used in the model. 

The open and close speed of the orifice modifies the orifice setting by changing the orifice setting based on the open and closing speed using the equation:

New Orifice Setting = Old Orifice Setting + (Target Setting – Orifice Setting) * Time Step / Orifice Open and Close Speed

If your target setting and the current orifice setting are both 1 or 0 then the orifice Open and Close option does not change the orifice setting.  New Settingequals Old Setting in that case.  If the target and  setting are out of phase then the Open and Close Option will function correctly.  For example, if the Openand Close Speed is 1 hour then the orifice setting will open and close in a one hour period.  The table shown below shows how the orifice setting changes as a function of the speed and the difference between the target and orifice settings.   The setting starts out open but the target says closed – the orificethen closes over a 1 hour period.  At one hour the target setting is 1 and the orifice will then open over a one hour period.

Table - Link OR1@82309b-15009b

                                Setting               Target         

Days         Hours                                                

0              00:00:00    1.00                  0.00           

0              00:15:00    0.74                  0.00           

0              00:30:00    0.50                  0.00           

0              00:45:00    0.25                  0.00           

0              01:00:00    0.00                  0.00           

0              01:15:00    0.25                  1.00           

0              01:30:00    0.50                  1.00           

0              01:45:00    0.75                  1.00           

0              02:00:00    1.00                  1.00           

0              02:15:00    0.75                  0.00           

0              02:30:00    0.50                  0.00           

0              02:45:00    0.25                  0.00           

0              03:00:00    0.00                  0.00           

0              03:15:00    0.00                  0.00           

0              03:30:00    0.00                  0.00            

0              03:45:00    0.00                  0.00           

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Conduit Lengthening in SWMM 5

Conduit Lengthening in SWMM 5

If you use the conduit lengthening option in SWMM 5  then your short conduits will be lengthened based on the CFL or explicit time step criterion.  Any conduits in which the Length Factor or the courant time step link length over the original length is greater than 1 will be lengthened and will have its roughness lowered so that the conduit is hydraulically the same at full conduitdepth.  The full area, full width and full hydraulic radius stay the same in the modified link – only the length, slope and roughness are altered.

Length Factor  = (Wave Celerity + Full Depth Velocity) * Time Step / Conduit Length, and for those links in which the Length Factor is greater than 1

New Roughness =  Old Roughness / (Length Factor) ^1/2

New Slope = Old Slope / Length Factor

A few metric's for showing how this option has altered the network are shown in the figure below:

1.    The most important is the increase in Network full volume as you never want to drastically alter the volume of your network,

2.    The number of conduits modified along with the new mean slope (lower) and the new total conduit length are important indicators,

3.    The mean wave celerity, full flow velocity and courant time step mean give the user some idea of the optimal time step for the simulation.

The Three Flows in SWMM 5 for a Link

The Three Flows in SWMM 5 for a Link

There are actually three flows computed or used for a link in SWMM 5:

1.    The St. Venant Flow equation flow

2.    The Upstream Normal Flow Manning's equation based on the link roughness, slope, upstream cross sectional area and upstream hydraulic Radius,

3.    The flow actually used in the model which is either the flow computed from St. Venant or Manning's equation

The following three links shows how this works in a real model:

·         Link 8040 almost always uses the St. Venant Equation because it is dominated by backwater and surcharge 

·         Link 8100 almost always uses Manning's equation except at the beginning and end of the simulation, 

·         Link 1600 is an adverse slope link and it mainly uses the St. Venant equation. 

·         Flow = the flow actually used during the simulation 

·         Qdynamic = the flow computed from the St. Venant Equation 

·         QNormUp = Flow based on Manning's equation at the upstream end of the link. 

·         QNormDown = Flow based on Manning's equation at the downstream end of the link.

Link 8100 almost always uses Manning's equation except at the beginning and end of the simulation.  The beginning and end of the simulation is when the non linear terms dominant.

How to Use the SWMM 5 Excel Tool with InfoSewer CSV Files

How to Use the SWMM 5 Excel Tool with InfoSewer CSV Files

1. Export Link and Manholes in InfoSewer for your current Scenario to CSV files,

2. Set up the Excel Add on for SWMM 5 by using the command Tools, and Configure Tools (see below)

3. Run SWMM 5 and edit the data in Excel, you should be able to copy and paste the information from the CSV files into the correct SWMM 5 sections. 

How to Use the SWMM 5 Excel Tool with InfoSewer CSV Files

Dual Drainage in SWMM 5

Subject:  Dual Drainage in SWMM 5

The purpose of the Dual Drainage tool in InfoSWMM is to create a major or street drainage network on top of an existing pipe or what is called the minor network in  dualdrainage.  The created major network has a node (sometimes called the inlet node) on top of the existing minor network node connected by two  OUTLET links.  One outlet link takes the flow from the street and  passes it to the minor network node, the second outlet link  takes the surcharged minor network flow and passes it to the major network or street – the direction of flow is important (Figure 1).  The general purpose of the Captured OUTLET is to  use a head or depth equation to separate the street incoming  flow into captured flow and bypass flow

Figure 1.  Dual Drainage in General

Figure 2.  How it looks in SWMM 5 with node, outlet and conduit elements.

Arc Map If Statements for Showing Flooding in InfoSWMM

Arc Map If Statements for Showing Flooding in InfoSWMM

You can use a combination of the Map Display in InfoSWMM and the Arc Map Label Properties to show the Maximum Ponded Volume at a node during amInfoSWMM simulation. 

The label function in VBSCRIPT to show just non zero flooded volumes(Figure 1) is:

Function FindLabel ( [PONDED_VOL] )

If [PONDED_VOL] > 0 THEN

  FindLabel = "" & FormatNumber([PONDED_VOL],2) & ""

END IF

End Function

and the values of Flooded Time,  Maximum Flooded Rate and Maximum Ponded Volume can be found in the Junction Attribute Table(Figure 2)  but not the Junction Summary Table of the InfoSWMM output report manager tables. 

A VBSCRIPT function to show both ponded volume and flooded rate (Figure 3) is:

Function FindLabel ( [PONDED_VOL], [FLOOD_RATE]  )

If [PONDED_VOL] > 0 THEN

  FindLabel = "" & FormatNumber([PONDED_VOL],2) & " / "   & FormatNumber([FLOOD_RATE],1)

END IF

End Function

Figure 1.  InfoSWMM Map Display of Ponded Volume which is the integral of node flooding over the flooded time.

Figure 2.   If you use the Map Display feature in InfoSWMM then the total flooded time, flood rate and maximum ponded volume will be shown in the Junction Attribute Table.

Figure 3.  Labels showing both Maximum Flooded Volume and Maximum Flooded Time on the InfoSWMM Map Display

InfoSewer Inflow Control for a Pump with a Pump Curve

InfoSewer Inflow Control for a Pump with a Pump Curve

You can control the pumps in InfoSewer and H2OMap Sewer by using a Pump Control which will control the pump based on: 

1.       Volume

2.      Level

3.      Discharge

4.     Inflow

5.      Time 

If you use a By Inflow control the pump speed of the pump is increased or decreased to make the Upstream Wet Well Level Constant (Figure 1) for an exponential 3 point curve

Figure 1.  Inflow Control for  PUMP in InfoSewer and H2OMAP Sewer will change the Pump Speed of the pump to make the Wet Well level constant

What are the LID Control Flow Source Options in SWMM 5?

What are the LID Control Flow Source Options in SWMM 5?

The SWMM 5 options for Low Impact Development (LID) controls on a Subcatchment are very flexible, exciting, possibly recursive and a completely integrated method to treat both the pervious and impervious flow.  You can send the Subcatchment runoff to either an outlet node, impervious area of the Subcatchment, the pervious area of the Subcatchment or another Subcatchment.   You can have the LID control receive a portion or all of the impervious flow OR as in the EPA SWMM 5 LID example have the LID cover the whole Subcatchment and receive both impervious and pervious flow from one or multiple upstream Subcsatchments.  For example,  Subcatchment Swale4 in Figure 1 is 100 pervious and has upstream runoff from the pervious and impervious areas of Subcatchments S1, S3 and S4 in Figure 1.  The LID can also have either an outlet node or the pervious area of the Subcatchment on which it resides.

Batch Simulation for InfoSewer, InfoSWMM or InfoWater, H2oMap SWMM, H2OMap Sewer and H2OMap Water

Steps to set up a new icon for Batch Simulation in InfoSewer, InfoSWMM or InfoWater

1. Customize Arc GIS

2. Add an Icon

3. Run the command using the Icon

Global Dry Weather Flow Reduction in InfoSWMM and H2OMAP SWMM - Updated

Global Dry Weather Flow Reduction in InfoSWMM and H2OMAP SWMM

A cool tip to reduce the overall dry weather flow in InfoSWMM and H2OMAP SWMM without changing the mean dry weather flow is to do the following:

1.       Make a Reduction or Increase Flow Pattern in the Operations tab of the Attribute Browser (2),

2.      For example, if we want to have 85 percent of the flow use a value of 0.85

3.      In the Node DWF DB Table (2) use the pattern just created (3)

4.      All of the flows in the DWF table and during your simulation will be reduced by 15 percent.

Importing a Link Shapefile into InfoSWMM via GIS Gateway

Here is how you map the shapefile pipe fields to the InfoSWMM data fields.  One note, you had two diameter fields (feet and inches) and the feet column was mostly zero so I used the inch column.  Here are the four steps and mapping you need to import all of the data from your shapefile.  You will have to use blockedit and convert the diameter from inches to feet in the DB link table (Step 5 – note there are still three missing pipe diameters).

Step 1.  Use the GIS Gateway command and set up the import of the file name, and ID field

Step 2. Set up the mapping between the Shapefile fields and InfoSWMM.  We used link offset and the pipe diameter in inches.

Step 3. Load the mapped shapefile

Step 4.  The imported data from your shapefile into the DB table of InfoSWMM

Step 5  Convert to feet from inches

How to Compile SWMM 5 in Visual Studio 2010 Express

How to Compile SWMM 5 in Visual Studio 2010 Express

Download the newest SWMM 5 code(Figure 1) from http://www.epa.gov/nrmrl/wswrd/wq/models/swmm/#Downloads and then make a new directory on your computer. We will call it c:\newSWMM5Code with a subdirectory C:\newSWMMCode\VC2005_DLL  in which the attached vcxproj file is placed.  The source code from the EPA should be placed on C:\newSWMMCode.  You can then open up the file swmm5_ms.vcxproj and make a new SWMM 5 DLL model with your code modifications (if needed).

Figure 1.  The source code from the EPA for SWMM5.

How to Use Trace Upstream, Domain Manager and Facility Manager in InfoSewer to Find the CE

Use Trace Upstream, Domain Manager and Facility Manager in InfoSewer to Find the CE

InfoSewer does not have table of node continuity errors only an overall continuity error balance.  If you have a continuity error then you can use the process of divide and conquer to find the continuity error.  Start at the Outlets and using the Trace Upstream command, Domain Manager and Facility Manager take out whole sections of the network until you isolate the section of the network with the continuity error.    Here are the steps you can take:

Step 1.             Use Trace Upstream Network to find the and place in a Domain the Upstream Network (Figure 1).

Step 2.                          Once the upstream domain is created use the Domain Manager to add in any extra links without nodes (Figure 2)

Step 3.             Make the Domain Inactive using Facility Manger (Figure 3)

Step 4.                        Run the network and check the overall continuity error (Figure 4)

Step 5.                         Continue and repeat until you isolate the area that is the main source of the Continuity Error (CE).

Figure 1.  Trace Upstream Network and Place it in a Domain

Figure 2.  Use Domain Manager to take out links without nodes

Figure 3.  Use Facility Manager to Make the Domain Inactive

Figure 4.  Find and Isolate the Area with the CE.

Wikipedia Traffic for the SWMM versus EPANET Articles

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 search name has switched from the word SWMM to Stormwater Management Model starting in 2009.