How is the Maximum Link Flow Applied in SWMM 5?

Subject:  How is the Maximum Link Flow Applied in SWMM 5?

The maximum flow limit for a link applies to the kinematic wave and the dynamic wave solution.   The inflow to the link  in the kinematic wave solution is limited (Figure 1) but the calculated link flow is limited in the dynamic wave solution after the link flow (Figure 2):

1.       Is checked using the Culvert Inlet Equations (optional)
2.      The normal flow equation is checked (internally optional depending on the Normal flow options) and
3.      The Picard iteration solution under relaxation parameter (always 0.5) is applied (Figure 3).

Figure 1.  Kinematic Wave Solution Limits the Inflow to  the Link Maximum limit.

Figure 2. Dynamic Wave Solution link  flow limit.

Figure 3.  The Link  flow in the dynamic wave solution has three checks at each iteration in a time step.

How to Make Contours in InfoSWMM and H2oMAP SWMM

Subject:  How  to Make Contours in InfoSWMM and H2OMAP SWMM

It is easy to make contours out of node input data or node output data in InfoSWMM and H2oMAP SWMM using the Contour Tool in the Contour Tab of the Attribute Browser.  You can control the resolution and the type of smoothing for the created contour (Figure 1).  If you haveInfoSWMM Suite you can use the Contour to DEM command in the Subcatchment Manager to convert the created Contour to an Elevation or DEM file (Figure 2 and Figure 3).   The Layer properties for the created elevation can be altered in Arc GIS to make a better visual depiction of the elevation (Figure 4).

Figure 1.  Contour Tool in the Contour Tab of the Attribute Browser.

Figure 2.  Contour to DEM command in the InfoSWMM Subcatchment Manager will convert the created Contour to an Elevation or DEM file.

Figure 3.  Convert the Value Field and  NOT the level Field of the contour.

Figure 4.  The Arc GIS Layer properties can be used to alter the default color ramp and the number of classes used in the color ramp.

InfoSWMM and H2OMap SWMM Facility Manager

The InfoSWMM Facility Manager offers the knowledgeable engineer complete control what elements are simulated in her or his model.  You can make active or inactivate elements based the type of Network Element, A Network Path, A Mouse Drawn Map Selection, The Domain, A selection set, a DB Query, a Query Set and a Special Query.  You can make the simulated network smaller or larger depending on your simulation or calibration requirements.  For example, you can have a whole basin network but model only a branch or a subset of the network if you are using the Calibrator or Designer Addons.

 

InfoSWMM and H2Map SWMM Selection Set and Domain Manager

Subject:   InfoSWMM and H2Map SWMM Selection Set and Domain Manager

You can use the Domain to easily make selection sets using these two steps.  You make a Domain which is the areas of the network you are interested in at the current time and then save your Domain of Interest in a Selection Set.

Step 1:  Go to Domain Manager and use Map Selection, Query or the Network to make a domain

Step 2.  Go to Selection Sets in the Operation Tab of the  Attribute Browser and make a New Set and load the domain into your set.

How to make a shape file from a Output Relate in InfoSWMM

Note:   How to make a shape file from a Output Relate in InfoSWMM

Step 1.  Make an Output Relate for the Conduit Summary Table using the Operation Tab in Attribute Browser.

Step 2:  Using the GIS Gateway you can save q/Q and d/D to a shape file that can then be added to the Arc GIS Table of  Contents

Step 3.   You now have a Shape File for the value of q/Q or Flow over Full Flow.  You can also use the Symbology Tab in Data Properties to color and/or make bar charts and bubble charts from the summary q/Q and d/D values during the simulation for each link.

Sensitivity Analysis in InfoSWMM and H2OMAP SWMM

Subject:  Sensitivity Analysis in InfoSWMM and H2OMAP SWMM   

  

It is easy to perform sensitivity analysis in InfoSWMM and H2oMAP SWMM using the Scenario Manager, Dataset manager, Block Edit in the Database Editor, Batch Simulation and theReport Manager.  For example, we will do a sensitivity analysis for the Subcatchment Width (one the physical parameters in the Subcatchment analysis of SWMM 5 – see Figure 1).  The width is normally the area divided by the overland path length but there are many common means of calculating the width.  

Figure 1.  Physical Data used in the Calculation of Surface Runoff using the Non Linear Reservoir Routing method in SWMM 5.

Figure 2.  The base scenario for our sensitivity analysis.

There are seven main steps in the sensitivity analysis of the width:

Step 1.   Use the Scenario Explorer to make Child Scenarios from the Base Scenario.  For ease of understanding we will name each of the Child Scenario's the percent change in the width parameter.  Thus, W-50, will be the Base Width Plus 50 percent.

Step 2.   Use the Dataset Manager to create different Subcatchment Sets that will be used for each of the Scenario's.  Again for ease of understanding we will use the name S_W+50 etc for the Sets to match the change in the Width Parameter.

Step 3.   Use the Scenario Manger to choose the right Subcatchment Set for Each Scenario.

Step 4.   Use the Database Editor to Edit and modify the Width of Each Subcatchment Set.

Step 5.   Use the Block Edit tool to multiply the Base Width Value by the needed value, 1.25, 1.50, 0.75, 0.50

Step 6.   Use the Batch Simulation Command to run all of the Scenario's.

                                               

Step 7.   Use Report Manager and the tool Compare Graphs to graph the results of Each Scenario together.

Step 8.   In Report Manager you can produce a table that shows the runoff for each of the different scenarios.

Pump Volume per Pump Event in SWMM 5

Subject: Pump Volume per Pump Event in SWMM 5

You can calculate the volume per startup event by using the Pump Summary Table in SWMM 5 and copying a few columns to Excel.   

1.   Go to the Pump Summary

2.   Copy Pump Name, Total Volume and Pump Startups to Excel

3.   Divide to get Pump Volume per Event

You will now have the average volume per event.

Pump	Total	Total Volume	Pump
Name	Volume (ML)	L Per Event	Startups
PUMP-11	0.006082	202.73	30
PUMP-13	0.005539	184.63	30
PUMP-15	0.006241	208.03	30
PUMP-17	0.0064	213.33	30
PUMP-19	0.005405	180.17	30
PUMP-21	0.006199	206.63	30

Inc.

How is the Volume Calculated in the SWMM 5 Groundwater Component?

Subject:   How is the Volume Calculated in the SWMM 5 Groundwater Component?

The groundwater component of SWMM 5 is found in the gwater.c code.  It (as is all of SWMM 5) is excellently written in small functions by Lew Rossman of the EPA during the SWMM 5 development process.  However, code being code sometimes it is easier to see how the code is functioning.  This blog or note tries to show that function. 

The groundwater component consists of groundwater data (gw in the equation) and aquifer data (a) in the equation.  The equation for the groundwater volume is shown in Figure 1.   The volume is the water content (theta) times the upper depth and the porosity of the aquifer times the lower depth (Figure 2).

Figure 1.  Groundwater Volume Calculations

Figure 2.  Lower and Upper Depth of the Groundwater Compartrment

Hierarchy of Your Network in InfoSWMM and H2OMAP SWMM

Subject:  Hierarchy of Your Network in InfoSWMM and H2OMAP SWMM

In both InfoSWMM and H2OMAP SWMM you can run a subset of the network by using the Facility Manager to make part of thenetwork inactive and not solved.  You can make the output files smaller if you are performing a continuous simulation and save only the results of All, the Domain Only or a Selection Set to the graphical output file (Figure 1).   Figure 2 shows a few ways to query, view, graph and perform statistics for the model run.

Figure 1.  Options for saving the Active Network Data to the Graphical Output Data Set.

Figure 2.  Output View, Query and Graphical Options.c.

Import of Sections from SWMM 5 into InfoSWMM and H2oMAP SWMM

Subject:   Import of Sections from SWMM 5 into InfoSWMM and H2oMAP SWMM

A very useful hidden feature of the import SWMM 5 to InfoSWMM and H2OMAP SWMM is the ability to import all of the data or just one section.  For example, you can import the LID data, DWF patterns, control rules, pollutants, transects and other data that is transferable between different networks.

 

History of SWMM to the Year 2005

Subject:   History of SWMM to the Year 2005

Note on the symbols:  The Gator is the University of Florida and the Beaver is Oregon State University.  The connection is they are both associated with water and Dr Wayne Huber.

For Post 2005 History of SWMM 5 you can see the history of SWMM 5 on the SWMM5 Wikipedia page

http://en.wikipedia.org/wiki/Storm_Water_Management_Model

How is the Mass Balance Calculated in the SWMM 5 Groundwater Component?

Subject:   How is the Mass Balance Calculated in the SWMM 5 Groundwater Component?

The groundwater component of SWMM 5 is found in the gwater.c code.  It (as is all of SWMM 5) is excellently written in small functions by Lew Rossman of the EPA during the SWMM 5 development process.  However, code being code sometimes it is easier to see how the code is functioning.  This blog or note tries to show the mass balance local function updateMassBal

The groundwater component consists of groundwater data (gw in the equation) and aquifer data (a) in the equation.  The equation for the groundwater mass balance is shown in Figure 1.   The infiltration, evaporation occur only over the perviousarea but the percolation out the bottom of the aquifer occurs over the whole Subcatchment.

Figure 1.  Groundwater Mass Balance

Node Comparison in InfoSWMM and InfoSewer

Note:  Node Comparison in InfoSWMM and InfoSewer 

1)    Is there an option to set the manhole sealing method (i.e. locked 

or unlocked) in InfoSWMM?  You set the Surcharged depth to a positive value to prevent flooding and keep the pipes under pressure.  You will still have flooding once the water surface elevation reaches the maximum depth + surcharge depth.  Unlike inInfoSewer the depths are not unlimited.

 2)    Is defining manhole diameter in InfoSWMM available?  You can set the default surface area of a node or make it a storagenode.  

 3)    Does InfoSWMM allow me to create parallel pipes with the same 

attributes similar to InfoSewer?  You can set the number of barrels in the attribute browser of DB Editor in InfoSWMM.

 

 4)    Can you please confirm that the only element allowed to leave a 

storage unit in InfoSWMM is a pump?  No, this is not true.  You can have a gravity main, orifice or weir leave a storage pond or lake.

 5)    Is there a tool to check for pipe diameter discrepancies in 

InfoSWMM similar to InfoSewer?  Yes, we have a similar Engineering Review and Network Audit Tools

6)    For load patterns, I do not see an option between stepwise and 

continuous in InfoSWMM, or is there?  InfoSWMM really only has stepwise linear DWF pattern though you can have a time series of inflows as well which gives you complete flexibility.

 7)    Does InfoSWMM offer modeling I&I using pipe length, pipe surface 

area etc… like in InfoSewer?   You can but there in not an easy translation,  You have Rainfall Induced Infiltration at a Node. You can relate this to the pipe length but it is not straightforward.

 8)    Is steady state simulation and design simulation available in 

InfoSWMM similar to InfoSewer?  You can do Steady State easily but design uses a Genetic Algorithm technique if you have InfoSWMMSuite.

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

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.