Output Statstics Manager to find negative flows with these parameters:

1.       Pipe Features

2.       Use a Domain with your force mains

3.       Select Flow

4.       Event Dependent

5.       Total – NOT Mean or Peak to  find the negative and positive flows

6.       Large NEGATIVE Flow Threshold

7.       Large NEGATIVE Volume Threshold

8.       Zero for Interevent Time to pick up all values

9.       You will get a table that shows you the minimun flows, and a histogram of the flows

Note:  The Keep and Dampen options and their effect on the four main terms of the St Venant equation. 

The four terms are are used in the new flow for a time step of Qnew:

Qnew = (Qold – dq2 + dq3 + dq4) / ( 1 + dq1)

when the force main or gravity main is full dq3 and dq4 are zero and  Qnew = (Qold – dq2) / ( 1 + dq1)

The dq4 term in dynamic.c uses the area upstream (a1) and area downstream (a2), the midpoint velocity, the sigma factor (a function of the link Froude number), the link length and the time step or

dq4 = Time Step * Velocity * Velocity * (a2 – a1) / Link Length * Sigma

where Sigma is a function of the Froude Number and the Keep, Dampen and Ignore Inertial Term Options.  Keep sets Sigma to 1 always and Dampen set Sigma based on the Froude number, Ignore sets Sigma to 0 all  of the time during the simulation

the dq3 term in dynamic.c uses the current midpoint area (a function of the midpoint depth), the sigma factor and the midpoint velocity.

dq3 = 2 * Velocity * ( Amid(current iteration) – Amid (last time step) * Sigma

dq1 = Time Step * RoughFactor / Rwtd^1.333 * |Velocity|

The weighted area (Awtd) is used in the dq2 term of the St. Venant equation:

dq2 = Time Step * Awtd * (Head Downstream – Head Upstream) / Link Length or

dq2 = Time Step * Awtd * (Head Downstream – Head Upstream) / Link Length

Normally, dq1 (Friction Loss / Maroon in the Graph) balances dq2 (Water Surface Slope Term or Green in the Graph) but often for links with a large difference between upstream and  downstream depths dq4 (Red in the Graph) can have a significant value.  If dq4 or dq3 are important then the depth of water to increases to pass the same flow using the Keep option over the Ignore.   If you have a link with a Froude number near or over 1.0 (Supercritical) then using Keep or Dampen  for the Options may result in depth differences.   The effect of Keep is to increase the “loss” terms in the St Venant Equation.   The effect of Dampen and Ignore is to decrease the sum of the “loss” terms in the St. Venant Solution and lower the simulated depth.

A surcharged node in SWMM 5 uses this point iteration equation (Figure 1):

dY/dt = dQ / The sum of the Connecting Link values of  dQ/dH

where Y is the depth in the node, dt is the time step, H is the head across the link (downstream – upstream), dQ is the net inflow into the node and dQ/dH is the derivative with respect to H of the link  St Venant equation.  If you are trying to calibrate the surcharged node depth, the main calibration variables are the time step and the link  roughness:

1.   Mannings’s N

2.   Hazen-Williams or

3.   Darcy-Weisbach

The link roughness is part of the term dq1 in the St Venant solution and the other loss terms are included in the term dq5.  You can adjust the roughness of the surcharged link  to affect the node surcharge depth.

Figure 1.  The Node Surcharge Equation is a function of the net inflow and the sum of the term dQ/dH in all connecting links. Generally, as you increase the roughness the value of dQ/dH increases and the denominator of the term dY/dt = dQ/dQdH increases.

Figure 2.  The value of dQ/dH in a link as the roughness of the link increases.

HOW MOSQUITOES FLY IN RAIN

Mariel Emrich in Talking Science:

Mosquitoes are as adept at flying in rainstorms as under clear skies. But how is that possible? Wouldn’t rain crush a mosquito to the ground since mosquitoes weigh 50 times less than raindrops?

David Hu, an assistant professor of mechanical engineering and biology at the Georgia Institute of Technology, and his graduate research assistantAndrew Dickerson have found that while mosquitoes do get hit by raindrops, they don’t get crushed by them.

Hu discussed their research in a talk at November’s APS Division of Fluid Dynamics Meetingthat was entitled “How Mosquitoes Fly in the Rain”.

The researchers measured the impact forces of raindrops on both regular mosquitoes and custom-built mosquito mimics. The mimics were made from small Styrofoam spheres of mosquito-like size and mass. They used high-speed video to capture images of the mosquitoes getting hit with raindrops.

Since the bugs fly so slowly (a maximum of 1 meter per second) compared to the drops (which fall between 5 to 9 meters per second), the mosquitoes cannot react quickly enough for avoidance, and most likely cannot sense the imminent collision.

More here.

Posted by Abbas Raza at 03:42 PM | Permalink

You can customize the toolbars in InfoSWMM and InfoSewer by clicking on Customize and performing 4 steps: 

Step 1.  Click on Customize

Step 2.  Move the tool from the Command list to the toolbar.

Step 3.  Change the Button Image for the Default Style.

Step 4.  The Toolbar now has a new Icon for the InfoSWMM command.

Step 1.  Click on Customize

 Step 2.  Move the tool from the Command list to the toolbar.

 Step 3.  Change the Button Image for the Default Style.

 Step 4.  The Toolbar now has a new Icon for the InfoSWMM command.

 If you cannot open ArcMap, InfoSewer or InfoSWMM at all and get a fatal Esri error the problem may be the file normal.mxt

“If the startup file in ArcGIS Desktop or component applications (e.g., ArcMap, ArcGlobe, ArcScene) is corrupt, a fatal error can occur. Renaming or deleting the existing startup file will often resolve the error. Once the corrupted startup file is removed, ArcGIS will create a new startup file after the application is launched (http://kb.iu.edu/data/asuv.html).”

To remove the startup file in Windows XP for Arc GIS 10 go to the directory C:\Documents and Settings\Your Name\Application Data\ESRI\Desktop10.0\ArcMap\Templates and delete the file Normal.mxt.   You then reopen Arc Map and the normal.mxt file will be recreated and smaller.  You will have to reset the ArcMap toolbars to better control InfoSewer and InfoSWMM.   

Subject:  SWMM 5 Engine Updates between v13 and v22 by Category

The complete list of engine and GUI changes can be found in this text file on the EPA Site http://www.epa.gov/nrmrl/wswrd/wq/models/swmm/epaswmm5_updates.txt

This note  categorizes the engine changes by aggregating dynamic wave solution changes, surface ponding changes, RDII and Hydrology for example.  The number preceding each change is the change number per engine update – the version of the engine update is shown at the end of each change paragraph.  The Categories are General Changes, Dynamic Wave Changes, RDII Changes, Infiltration and Surface Runoff Changes, Climate Data Changes, Rainfall  Changes, LID Changes and Water Quality Changes.

In SWMM 5 only the Kinematic Wave solution allows a flow divider at a node to divide the Inflow to node to two  downstream  links, but you can use the Inflow/Outflow Outlet type in InfoSWMM to divide the inflow based on a Inflow/Outflow Diversion Table (Figure 1).  For example, in InfoSWMM it is possible to have two downstream links from a Node that are Outlet types Inflow/Outflow so that the low flow goes down one link and the high flow goes down the other link (Figure 2 and Figure 3).   The low flow and the high flow  link  use different diversion tables in which the tables are constructed so that the flow is positive in one link and zero in the other to a dividing flow value and then zero and positive for the same two links after the dividing flow value ( 5 cfs in the example).

Figure 1.  Types of OUTLETS in InfoSWMM and SWMM 5

Figure 2.  Example low flow and high flow Outlet Links to divide the total  inflow at the upstream node at 5 cfs.

Figure 3.   The flow is divided into the low and high flow links at the dividing flow of 5 cfs.

CDM and Wilbur Smith Associates Proudly Serving Clients

as CDM Smith

New brand reflects emergence of a full service global leader

January 01, 2012

CAMBRIDGE, Massachusetts—What began in February 2011 with joining of two industry forces has culminated in a fully integrated provider of comprehensive water, environment, transportation, energy and facilities services united under the new brand CDM Smith.

According to Chief Executive Officer Richard D. Fox, “CDM Smith brings together CDM and Wilbur Smith Associates, two firms of rich heritage and world-wide reputation. With 123 years of combined cross-discipline expertise, our people bring a wealth of knowledge, experience and dedication to every client relationship and each project. While our name is different and our portfolio of services has expanded, we remain committed to doing what is right for our clients, our communities, each other and the future.”

Proving to be better together, CDM Smith represents almost 6000 employees excelling in 100 technical specialties, partnering with clients to solve challenges in 28 countries around the world.

CDM Smith provides lasting and integrated solutions in water, environment, transportation, energy and facilities to public and private clients worldwide. As a full-service consulting, engineering, construction, and operations firm, we deliver exceptional client service, quality results and enduring value across the entire project life cycle. 

Your network data usually has a number of different attributes that describe the features it represents (Figure 3). While you’ll commonly use one of the attributes to symbolize the

data—for example, showing one quantity in the InfoSWMM Map Display —you may sometimes want to use more than one.   One way to show multiple attributes in InfoSWMM is to copy layers and then use the Layer Properties to color, map or otherwise display the multivariable data (Figure 1).  For example, Figure 2 shows the important Subcatchment parameters of Slope, Imperviousness and Width as graduated colors, dots and a pie shape, respectively.

Figure 1.  Use the Symbology Tab to select the attribute you want to show and the way to show the attribute.

Figure 2.   The Subcatchment slope is shown in graduated colors, the percent impervious in scattered dots a a measels map and the Subcatchment Width is shown in a pie graph with the size of the pie a function  of the total  width.

Figure 3.  Physical Data Estimated from a DEM using the Subcatchment Manager in InfoSWMM.

The Subcatchment Manager of InfoSWMM will  help calculate most of the  physical parameters associated with a Watershed or Subcatchment in SWMM 5 from a Digital Elevation Data (Step 1).  The Subcatchments slope is estimated from a slope raster (Step 2) and the Slope Calculator (Step 4). The created watershed area are calculated using the command Update DB from Map (Step 6) along with the Subcatchment Width (Step 3) and the Impervious Area (Step 5).   The physical parameters estimated from the DEM are shown in Figure 1.

Figure 1.  Physical Data Estimated from a DEM using the Subcatchment Manager in InfoSWMM.

Step 1.  Use the command Create Flow Stream to create a Flow Stream for the DTM or DEM that can be used later.

Step 2.   Create a Slope Raster from the DEM for later usage in the Slope Calculator.

Step 3.   Calculate the Width of the Subcatchment using one of five methods.

Step 4.   Calculate the Slope in percent from the Slope Raster created in Step 2.

Step 5.   Populate the Impervious area percentage using a Parcel shape file and the Created Subcatchments.

Step 6.   Use Arc Map to calculate the area of the Subcatchments using the command Update DB from Map and the following Operation Flags.

The Subcatchment Manager of InfoSWMM will  help calculate most of the  physical parameters associated with a Watershed or Subcatchment in SWMM 5 from a Digital Elevation Data (Step 1).  The Subcatchments area created from a Flow Direction Raster (Step 2) and a Flow Accumulation Raster (Step 4) after filling in any Sinks in the DEM (Step 3).  The created watersheds (Step 5).   The physical parameters estimated from the DEM are shown in Figure 1.

Figure 1.  Physical Data Estimated from a DEM using the Subcatchment Manager in InfoSWMM.

 Step 1.  Find, Create or Otherwise Locate a TIN, DEM or DTM for the project area with elevation data that you can  use with the InfoSWMM Subcatchment Manager.

 Step 2.   Create a Flow Direction Raster using the Watershed Command.

 Step 3.   Check to see if there are Sinks in the Elevation Data that have to be filled using the Filled Sink Command.

 Step 4.   Create a Flow Accumulation Raster

 Step 5.   Create the Watersheds from the Flow Direction and Flow Accumulation Rasters.

Subject:   Continuous Simulation Aids for InfoSWMM

If you have a large network and especially if you are doing continuous simulation then you want to have many tools for helping you understand the network and the simulation results.  

v  In InfoSWMM and H2OMAP SWMM you can have a Base Network with many differenct Child Scenaio generations.  A Child can be either based on the Base Scenario of a different generation Child Scenario.

v  Facility Manager allows you to make inactive and active sets areas of your network, which makes simulating larger and smaller models a snap to do in InfoSWMM.   Run Manager lets you control which areas of the model  network gets save to the  binary graphics file (Figure 1). 

v  The Process Control in  Run Manager (similar to the process control in SWMM 5) allows the modeler to control  which processes are simulation to  help in her model  calibration.

Figure 1.  Scenarios, Facility Manager and Run Manger Options.

Figure 2.  Run Manager Process Controls.

You can make tables of the node,  link  and  Subcatchment output data in SWMM 5 if you use the DOS SWMM 5 program but not the Windows DLL.   Step 1 is to create the DOS batch file, Step 2 is to select the nodes, links and subcatchments, Step 3 is to run the batch file and Step 4 is to view the RPT tables or extract the data to Excel.  You can do this directly in the InfoSWMM and H2OMAP SWMM graphical user interfaces by using Run Manager, Step 5 to select the nodes, links and subcatchments and Step 6 to view the tables in the browser.

Step 1.   Make a Batch File to call the DOS SWMM 5

swmm5.exe Example1.inp  D:\swmm5.0.022\bob.rpt

pause

Step 2.  Add the nodes,  links and  subcatchments tables you want to generate in the RPT file

[REPORT]

CONTROLS         NO

LINKS                 ALL

NODES               ALL

SUBCATCHMENTS ALL

Step 3.  Run the Batch file

Step 4.  Extract the Tables from the RPT File of SWMM 5

<<< Node 17 >>>

  ———————————————————————————

                           Inflow  Flooding     Depth      Head       TSS      Lead

  Date        Time            CFS       CFS      feet      feet      MG/L      UG/L

  ———————————————————————————

  JAN-01-1998 01:00:00      0.000     0.000     0.000   980.000     0.000     0.000

  JAN-01-1998 02:00:00      5.910     0.000     0.608   980.608    26.065     5.213

  JAN-01-1998 03:00:00     11.935     0.000     0.887   980.887    22.826     4.565

  JAN-01-1998 04:00:00     18.291     0.000     1.143   981.143    21.176     4.235

  JAN-01-1998 05:00:00     12.640     0.000     0.916   980.916    22.426     4.485

  JAN-01-1998 06:00:00      3.925     0.000     0.493   980.493    27.578     5.516

  JAN-01-1998 07:00:00      0.388     0.000     0.161   980.161    38.134     7.627

  JAN-01-1998 08:00:00      0.067     0.000     0.071   980.071    26.937     5.387

  JAN-01-1998 09:00:00      0.029     0.000     0.048   980.048     1.878     0.376

Step 5.  InfoSWMM and H2OMAP SWMM dialog for selecting nodes, links and subcatchments for generating a detailed RPT file table.

Step 6.  Sample InfoSWMM and H2OMAP SWMM RPT Tables if Report Options is used.

The RDII method in InfoSewer is similar to the RDII or RTK  method in  InfoSWMM with some differences.    The RTK data for triangles 1, 2 and 3 are defined in the Unit Hydrograph but instead of individual R values, the overall R is set and the Percent R1,  R2 and R3 are defined based on the total  R.  R3 is calculated internally as 100 – R1 – R2.   Each loading manhole with RDII flow has a total  area, a hyetograph and a Unit Hydrograph.  The hyetograph has to be set at multiples of the unit hydrograph, so you can define the time or X columns with integers and then use the Block Edit command to change X to minutes by multiplying  by the Unit Hydrograph time (Figure 1).   You can use only one component if you set R1 or R2 to 100 percent or R3 to 100 percent by setting R1 and R2 to 0 percent (Figure 2).  The overall area of the Unit Hydrograph is divided amongst the loading manhole using the Subbasin Area (Figure 3).   The storm flows generated can be viewed using a Group Graph (Figure 4).

Figure 1.   Hyetograph Curve for the RDII Unit Hydrograph

Figure 2.  The Unit Hydrograph is defined for various values of R, R1,  R2, T1,  T2,  T3, K1,  K2 and  K3.

Figure 3.  The Unit Hydrograph and Hyetograph are tied to a particular loading manhole using a Subbasin Area.

Figure 4.  The Unit Hydrographs that are generated can be viewed using a Group loading Manhole Graph.  The R1, R2 and R3 have only one triangle.

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.

If the slope of a link  is negative and the solution  is dynamic wave then the following data will be switched in link.c in SWMM 5.  All upstream data for the  link  is switched to the downstream end of the link  and  vice versa.   The means that if the flow  is from the original upstream node to the downstream node the flow  will  be negative in the output of  SWMM 5.

Negative flow in SWMM 5 means:

1.   The link has an adverse or negative slope,

2.   The link  has reverse flow if the link slope is positive. 

 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.

You can use the Upstream Trace tool in InfoSewer to find the upstream nodes and links from any link in InfoSewer.   Once you have the upstream traced network then add the traced upstream nodes and links to the  domain.  Once you have the domain then these steps will allow you to calculate the proportion of flows from each upstream node and map the proportion using Map Display.

Step 1.  Use the Tool Trace Upstream Network to find and make a Domain out of the Traced upstream Network

Step 2.  The Traced Upstream Network

Step 3.  Use the created domain in Output Report Tabular Reports

Step 4.  Copy the ID and Total Flow from the Loading Manhole Report

Step 5.  Use the Domain in the DB Table Manhole Infomation

Step 6.  Create a new information field called Proportion for example

Step 7.  Map the new data field proportion using Map Display

Step 8.  Now you have a Map Display of the Proportional loading to a link  or manhole in InfoSewer

Step 9.  40 percent of the flow comes from one node an the other 60 percent comes from the other node to the link with a d/D over 0.5.

A great feature of Arc GIS 10 is the ability to use background maps from Bing for your model.  A few steps are necessary to set up the coordinates, import the basemap, clip the basemap and set the new extents:

Step 1.  Set the Current Coordinate System for the intended network.

Step 2.  Add the Aerial Basemap from Bing Maps.

Step 3.  The Base Map has to be clipped and zoomed.

 Step 4.  Zoom to your network and clip the rest of the Map out of the Maximum Extents.

 Step 5.  Set the Maximum Extents of your Network using the Data Frame Tab in Data Frame Properties.

 Step 6.  You can also set the background color for the area outside of the clipped Base Map if you so desire using the Frame Tab.

 Step 7.  You now can add nodes and links and view the locale using Google Street View or other using the Tools Prefences.

Engineers can now link a building’s rainwater catchment system to weather predictions from the Internet. Alerted city services can then empty water storage basins so that stormwater doesn’t flood our sewers:

It may sound like a trivial problem, but the EPA estimates that the U.S. has $13 billion invested in wastewater infrastructure alone. More importantly, the majority of America’s largest cities–more than 700 in all–dump millions of gallons of raw sewage into our waterways every time it rains, because their sewer and stormwater systems were designed a century ago. …

Giving building planners the assurance that they’ll always have access to a free water supply means they can actually use it. And putting these on enough buildings could go a long way to solving the problem of combined sewer and stormwater systems being overwhelmed when it rains.

(Photo: Residents try to unblock a sewage grate to free floodwater on Coney Island after Hurricane Irene hit New York, August 28, 2011. By Emmanuel Dunand/AFP/Getty Images)

http://andrewsullivan.thedailybeast.com/2011/12/connecting-infrastructure-to-the-internet.html

 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 the Report 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.

 Figure 1.  Location of Files Command in Run Manager

The inflows will be read  from the Inflows file, which has this format:

Figure 2.  Header format of the CUHP Exported Hydrograph File

InfoSWMM and H2oMAP SWMM will match the Node Names in the Inflows file to the network node names and import and interpolate the inflows based on the Inflows time step and your hydraulic time step to generate Lateral  Inflow Hydrographs

Figure 3.  InfoSWMM and H2OMAP SWMM Lateral  Inflow Hydrographs

Figure 4.  CHUP Inflows File Descrpiption in the CUHP manual.

Figure 5. Cover of CUHP 2005 User Manual from 2010

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 have InfoSWMM 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.

 A storage node in SWMM 5 can have either a functional form or a tabular depth/area table.  The area functional form of a storage node is:

 Area           =      A * Depth^B + C  and the Volume has the form in  node.c of the SWMM 5 of

 Volume     =      A/(B+1)*Depth^(1+B) + C*Depth

 For example if C is 25 square meters, A is 20 and the exponent B is 0.5 we get the following values for area and volume and you can also plot a Scatter Plot of Volume vs Depth in SWMM 5 (Figure 1).

 Table 1.  Area and Volume for a Storage Node in SWMM 5.

Figure 1.  You can use a Scatter Graph in SWMM 5 to show the relationship between Volume and Depth.

Subject:  Lambda Calculus in the SWMM 5 Dynamic Wave Solution

SWMM 5 uses the method of Successive under-relaxation to solve the Node Continuity Equation and the Link Momentum/Continuity Equation for a time step.  The dynamic wave solution in dynwave.c will use up to 8 iterations to reach convergence before moving onto the next time step.  The differences between the link flows and node depths are typically small (in a non pumping system) and normally converge within a few iterations unless you are using too large a time step.  The number of iterations is a minimum of two with the 1^st iteration NOT using the under-relaxation parameter omega. The solution method can be term successive approximation, fixed iteration or Picard Iteration, fixed-point combinatory, iterated function and Lambda Calculus. In computer science, iterated functions occur as a special case of recursive functions, which in turn anchor the study of such broad topics as lambda calculus, or narrower ones, such as the denotational semantics  of computer programs (http://en.wikipedia.org/wiki/Iterated_function). 

In the SWMM 5 application of this various named iteration process there are three main concepts for starting, iterating and stopping the iteration process during one time step:

·         The 1^st guess of the new node depth or link flow is the current link flow (Figure 3) and the new estimated node depths and link flows are used at each iteration to estimate the new time step depth or flow.  For example, in the node depth (H) equation dH/dt = dQ/A the value of dQ or the change in flow and the value of A or Area is updated at each iteration based on the last iteration’s value of all node depths and link flows.  

·         A bound or a bracket on each node depth or link flow iteration value is used by averaging the last iteration value with the new iteration value.  This places a boundary on how fast a node depth or link flow can change per iteration – it is always ½ of the change during the iteration (Figure 1).  

·         The Stopping Tolerance (Figure 2) determines how many iterations it takes to reach convergence and move out of the iteration process for this time step to the next time step.

Figure 1.  Under relaxation with an omega value of ½ is done on iterations 2 through a possible 8 in SWMM 5. This is not done for iteration 1.

Figure 2.  if the change in the Node Depth is less than the stopping tolerance in SWMM 5 the node is considered converged.  The stopping tolerance has a default value of 0.005 feet in SWMM 5.0.022. 

Figure 3.  The differences between the link flows and node depths are typically small (in a non pumping system) and normally converge within a few iterations unless you are using too large a time step.  The number of iterations is a minimum of two with the 1^st iteration NOT using the under-relaxation parameter omega.

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.

You can model 8 options in H2OMAP Sewer and InfoSewer to simulate various aspects of Water Quality (Figure 1).  If you make the base scenario no water quality you can have the same network, same loading but different aspects of water quality in seven child scenario’s (Figure 2).  The parameters for each water quality option is shown in the Quality Tab of the Simulation Options Dialog. 

Figure 1.  Water Quality Simulation Choices in H2OMAP Sewer and InfoSewer.

Figure 2.  Water Quality Simulation Choices in the Scenario Explorer of H2OMAP Sewer and InfoSewer

InfoSWMM 2D uses standard SWMM 5 components to connect the 1D Nodes to the 2D Mesh.  A bottom outlet orifice at the maximum depth of the node drains to a SWMM 5 Outfall at the fixed elevation equal to the Node Rim Elevation. Flow can go into or out of the Outfall from the 1D element from or to the 2D Mesh. InfoSWMM 2D automatically makes the necessary elements if 2D is used and the new elements are listed in the Hydqua.inp file, which is very similar to the Tab Delimited SWMM 5 Input file. 

The HYDQUA.inp is very similar to the Excel Tab formatted file of SWMM 5 with a few additional sections and added features:

1^st Difference:   The Flood Node Data Section tell the 2D engine which Node has a 1D-2D connection and which 2D mesh element the 1D Node drains to when it is flooded.

[Flood_Node]

10309D      848

80408        131

2^nd Difference:  Outfall Nodes are created for the 2D Mesh Element connected to the 1D Node, the outfalls are Fixed Outfalls and the fixed head is the Node Rim Elevation of the 1D node listed in the Flooded Node Section

[OUTFALLS]

10208  89.900000     FREE  NO

10208A           89.900000     FIXED            94.400000     YES

10208B           89.900000     FREE  NO

10208C           89.900000     FREE  NO

10208D           89.900000     FREE  NO

10208E           89.900000     FREE  NO

10309D_OUTFALL           101.600000            FIXED           111.000000           NO

80408_OUTFALL             120.000000            FIXED           133.400000            NO

3^rd  Difference:  Bottom Outlet Orifices are created to connect the 1D node to the 2D Mesh Element Outfall with the Flood Discharge Coefficient entered by the user and a crest height equal to the maximum depth of the node

[ORIFICES]

OR1@82309B-15009B  82309B      15009B      BOTTOM    0.000000   0.850000   NO

OR1@82309D-82308D  82309D      82308D      SIDE0.000000   0.850000   NO

10309D_ORIFICE       10309D      10309D_OUTFALL       BOTTOM    9.400000   0.030000   NO

80408_ORIFICE          80408        80408_OUTFALL         BOTTOM    13.400000 0.030000   NO  

The current version of InfoSWMM and H2OMAP SWMM not only imports the latest SWMM 5 version but it has built in flexibility that allows the user to import selected data sections, model data sections or auxiliary file information such as calibration data files.  This allows you the choice of importing non specific network data that can used in the model of any city, county, shire, town or watershed.  For example,  you can import only these sections without affecting the geometry of your network:

1.      Calibration File Information,

2.      RTC Rules

3.      Aquifers

4.      Snowpacks

5.      Buildup for Water Quality,

6.      Washoff for Water Quality,

7.      Evaporation,

8.      Time Series,

9.       DWF,

10.        Patterns,

11.        RDII

12.        Loadings,

13.        Curves,

14.        LID Controls,

15.        LID Usage,

16.        Pollutants,

17.        Land Uses

 Possible uses of this feature would be to have a city wide or company wide library of LID controls, RTC Rules or RDII values.

 Figure 1.  Import Dialog with Import Options

 Figure 2.  Only names and directories of the Calibration Files was imported

The value of the total inflow in the text output file is the integrated total for the whole simulation including all time steps.   This is the total volume that is shown in Map Display for Nodes and Links or in the Summary Tables for Nodes and Links.   If you graph the flow or depths in Output Report Manager and use the Field Statistics tool it will only show you the statistics for the SAVED time steps.  However, if you multiply the Sum (Total) Value by the saved interval in seconds you will have another estimate of the total node of link  statistic.  For example, a Sum Total of L/s times seconds yields liters which divided by 1,000 yields ML. 

Figure 2.  Map Display of  the  total link volume in the model run comes from the Node Inflow Summary Table in the Text Report File

  ***********************

    Node Inflow Summary

  ***********************

  ————————————————————————————-

                                  Maximum  Maximum                  Lateral       Total

                                  Lateral    Total  Time of Max      Inflow      Inflow

                                   Inflow   Inflow   Occurrence      Volume      Volume

  Node                 Type           LPS      LPS  days hr:min    10^6 ltr    10^6 ltr

  ————————————————————————————-

  PN_060               JUNCTION      0.00     2.93     0  07:47       0.000       0.143

In this example, we compare the force main head loss in four links in H20Map SWMM to the head loss in a steady state Hazen Williams solution for the same length pipe, diameter and flow (Figure 1).  The H2OMap SWMM model has a large constant dry weather inflow at the wet wells which floods the wet well and causes a constant pump flow to the force main (Figure 2).  The HW calculator is located here http://www.engineeringtoolbox.com/william-hazens-equation-d_645.html and a comparison for HW head loss in PSI for 5000 feet long, 3 inch diameter pipes with HW Coefficients of 130, 120, 110 and 100, respectively, is shown in Table 1.   The SWMM 5 equation loss (PSI Diff) and the PSI loss from the HW calculator are very close for all four links. 

Table 1.  Steady State comparison between HW Calculator and H2OMAP SWMM/SWMM 5 Force Main calculations.

Figure 1.   H2OMAP SWMM Wet Well, Pump, Force Main and Gravity Main Network.

Figure 2.  Constant Pump Flows

 In each of the blogs search  for a term or a set of terms using the search button.   For example, here is http://swmm5.blogspot.comwith a search for venant

 An equivalent Search in http://www.swmm2000.com

  An equivalent Search in http://swmm5.wordpress.com/

 An equivalent Search in http://swmm5.posterous.com

InfoSewer for Arc GIS 9 and 10 and  H2OMAP Sewer had a many engine and GUI enhancements during 2011 to allow the programs to work better for models up to 50,000 elements that simulate water quality and hydrology.  The improvements now allow large models to be run with smaller report and simulation time steps and provide a Mass Balance Check  at the end of the report file for the user to easily check the model results.  The new ForceMain Solution for EPS simulations now allows the simulation of complicated Force Main Loops in the network without the need for making simplifying network connection assumptions.  The engine changes make InfoSewer andH2OMAP Sewer more robust for large models and small time steps while  providing better solution error checking and routing.  The enhanced Output Report Manager shows all of the possible Node and  Link Output Variables in Graphs, Tables and Advanced HGL Labeling.  The year 2011 was a year in which the internal engine of InfoSewer and H2OMAP Sewer were improved and also a year in which more simulation output information was shown to the user so that they can both understand and explain the modeling results in a more confident fashion.

Figure 1.  Three Temporal Solutions in InfoSewer and H2OMAP Sewer

The three types of solutions in InfoSewer and  H2OMAP Sewer: Steady State, Design and Extended Period Simulations had other new features in InfoSewer and H2OMAP Sewer which include

·         Advanced Forcemain Network Support (Figure 3)

·         Plan Profile Plotting of the Input Network

·         Mass Balance Table for EPS Simulations (Figure 3)

·         Advanced Node and Link labeling for HGL Plots

·         A complete list of node, link graphics for all Output Attribute Browser Variables

·         Better memory allocation for long simulation and enhanced memory allocation for plot with many data points

·         Improved Memory Management for Water Quality, Pumping and Unit Hydrograph Simulations

·         Expanded Output Manager Tabular Reports for EPS Simulations

·         Expanded Warning and Error messages in the text report file

·         Enhanced water quality routing through force mains, pumps and wet wells (Figure 2)

·         Enhanced export to H2OMAP SWMM

·         Enhanced simulation of small hyetograph time steps for hydrographs

·         Expanded output for the Design Feature of H2OMAP Sewer

·         Improvements to the DB Editor for Import of GIS and  OBDC data

·         The ability to run longer simulations with shorter report time steps

·         Enhancements to the pump allocation routine for Steady State and EPS runs

·         Improvements to the ranges of the solution parameters for the Muskingum-Cunge modified solution

·         Output Graphics can now be shown down to a 1 second report step.

Figure 2.  Example InfoSewer Network with Multiple Upstream and Downstream Force Main Links.

Figure 3.  The new ForceMain Solution allows InfoSewer and H2OMAP Sewer to simulate Force Main Splitting and Joining

Figure 4.  Mass Balance Check in InfoSewer and H2OMAP Sewer now shows the user the  total inflow, storage and  total outflow during the EPS Simulation.

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. 

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 pervious area but the percolation out the bottom of the aquifer occurs over the whole Subcatchment.

Figure 1.  Groundwater Mass Balance

Make study more effective, the easy way

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

In both InfoSWMM and H2OMAP SWMM you can run a subset of the network by using the Facility Manager to make part of the network 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.

 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.

SWMM 5 has three loss terms available for each link:  Entrance, Exit and Other losses.  The Entrance loss uses the upstream link velocity, the  Other loss uses the center link velocity and the Exit loss uses the downstream link velocity.  The general form of the loss term in the St. Venant equation is K*V^2/2g Table 1 shows the loss in feet of head for various combinations of velocity and K value.  If you want to  simulate a little loss of head at each node then a small value of K should be used otherwise the cumulative loss in the whole networks will be many feet of head.

  Loss Term units equals K * V^2/2g = ft/sec * ft/sec * sec^2/ft = ft

Table 1:  Loss in feet of head for various combinations of velocity and K values.

 The newer option for SWMM 5 culverts uses three culvert classifications and associated equations to compute the inlet controlled flow into a culvert using the FHWA (1985) equations.  The culvert code in the culvert.c code of SWMM 5 uses:

 1.   Two Equations for Unsubmerged culvert flow,

2.   One Equation for the Transition flow, and

3.   One Equation for Submerged flow.

Understanding Your Model Output in H2oMAP SWMM and InfoSWMM

Minimum Time Step               Average Time Step        Maximum Time Step

Minimum Time Step (sec)             0.984

Average Time Step (sec)              9.071

Maximum Time Step (sec)            30.000

Percent in Steady State (%)          0.000

Average Iterations per Time Step  4.821

Use a maximum time that will lower your average iterations per time step to speed up the simulation,decrease the maximum time step to lower the number of iterations, use equivalent conduit lengthening to increase

 the minimum time step, the model is fastest if the minimum and maximum time steps are not too small or large compared to the average time step.  Adjust the stopping toleranceand the number of iterations if you can to speed up your model

You can also decrease the number of iterations or the stopping tolerance to speed up the model or improve the continuity error of the model.   If you are doing a continuous simulation then you can have a reduced graphical output data set to speed up the simulation

If you have a duo or quad core computer another option to speed up the simulations is to use 1, 2, 3 or 4 cores for the simulation

The node invert elevation or the node maximum depth can be interpolated if you use the Elevation Interpolation Tool in H2OMAP SWMM.

Steps	Action
1.   Make a Contour Plot of the Node Invert Elevations.
2.   The Created Contours are now a layer in H2OMAP SWMM.
3.   Recreate the Invert Elevation from the Contour by using the Value Field and Interpolate Field.
4.   You can  also estimate the Maximum Depth of the Node from the Contour and the known Node Invert Elevation.

 Step 1.   Pump Startup and Shutoff Depth

 Depths to turn the Pump On and turn the Pump Off.  In this example, the pump will be off when the Wet Well Depth is less than 2 feet, the Pump will be off between a Wet Well Depth between 2 and 5.75 feet if the Pump is currently Off and the Pump will be On between a Wet Well Depth between 5.75 and 2 feet.

 Step 2.   RTC Rule for the Pump Setting when the Wet Well Depth is less than 6.25 feet.  We need to add the AND statement so that the setting is only reset when the Pump is On.   You do not want the pump setting to be reset when the pump should be off.

 Result 1:  The Pump Speed Ratio tells you the Pump Setting

 Result 2:  RTC Control Rules in the RPT File if you click on Show Control Actions

Result 3:   The depth at the Wet Well and the Flow in the Pump

Result 4:  A mixed graph of the Wet Well Depth and Pump Flow shows the effect of the RTC.

Result 5:  The RTC Rule can also been seen flow to the Pump Curve.

It is very easy to read the output graphs and output text file from older versions of SWMM 5 in newer versions of SWMM 5 as long as the rules are followed:

1.   You need to have the RPT file for the InputFileName or InputFileName.RPT

2.   You need to have the OUT file for the InputFileName or InputFileName.OUT

3.   The File Size for InputFileName.RPT is greater than 0

4.   The Run Status for InputFileName.OUT is true based on the tests in CheckRunStatus

a.       // Starting from end of file, read byte offsets of file’s sections

b.       // Read # time periods, error code & file signature

c.       // Read file signature & version number from start of file

d.       // Check if run was completed

e.       // Check if results were saved for 1 or more time periods

f.        // Check if correct version was used

g.       // Check if error messages were generated

 Figure 1.   The RPT File or OUT File is not saved unless you 1^st save the Current Simulation Results.

Figure 2.   The binary output file of SWMM 5.0.013 in SWMM 5.0.022

This note attempts to explain both how the head upstream and the head downstream of a weir in SWMM 5 is calculated compared to the weir crest elevation and also to explain how the weir is presented in the HGL plot of SWMm 5.  There has been confusion in the past concering how the weir is shown compared to the actual weir calculations.  The node head is calculated obviously at both ends of the weir but the head over the weir is always based on H1-Crest or H2-Crest (Figure 1) and hence the weir should look flat – to the weir the downstream head is important but NOT the downstream node invert so the weir really is flat and should look flat in the HGL Profile across the weir (Figure 2).    The crest elevation is always relative to the upstream node invert elevation NOT the downstream node invert elevaation

Figure 1.  How the Head across a Weir is calculated in SWMM 5

Figure 2.   HGL Profile across a Weir in SWMM 5.0.022.  The black line should be shown flat.

Note:  For the 1^st time in 4 years we have had a visitor from Central Asia.  This now means we have had visitors from all Google defined Geographic Regions on Earth even though we still have not had visitors from every country at www.swmm2000.com  The statistics below exclude the 58 percent visitors from North America but overall we have had:

 1.   40,190 Visitors

2.   22 Continental Regions

3.   157 Countries

4.   5951 Cities

5.   100,180 Pageviews

6.   86 Languages

The time step actually used during the simulation is related to this velocity and the safety adjustment factor.  The larger the safety adjustment factor the larger the mean time step listed in the Routing Time Step Suggestion.

The Cheerful World Of Japanese Manhole Covers

by Maisie Allison

Michelle Aldredge introduces us to a minor feat in public art:

One of my favorite book discoveries this summer is Drainspotting

 by Remo Camerota. The book celebrates an array of fascinating manhole cover designs from Japan. According to Camerota, nearly 95% of the 1,780 municipalities in Japan have their very own customized manhole covers. The country has elevated this humble, practical object to its own art form. The designs depict everything from local landmarks and folk tales to flora and fauna and images created by school children. Camerota explains the evolution of these custom covers in Drainspotting  http://www.gwarlingo.com/2011/drainspotting-61-amazing-manhole-covers-from-japan/

“In the 1980s as communities outside of Japan’s major cities were slated to receive new sewer systems these public works projects were met with resistance, until one dedicated bureaucrat solved the problem by devising a way to make these mostly invisible systems aesthetically appreciated aboveground: customized manhole covers.”

An oft requested feature in SWMM 5 is the ability to better simulate a variable speed pump.   The basic feature we are trying to model is multiple pumps between two nodes, one pump curve for all of the pumps and the ability to turn on and turn off the pumps based on either the head or depth at a Wet Well (Figure 1).  You can turn on or off the pumps Pump1, Pump2 and Pump3 based on the depth at the Wet Well but this feature is stepwise linear and usually uses three pump curves.  A better way to simulate this feature is to use the SWMM 5 Real Time Rules (RTC) to simulate the Pump setting based on a control curve.

The Pump flow at any time step is the Pump Flow estimated from the Pump Curve (Figure 2) * The Pump Setting (Figure 3)

Each of the three pumps has a different Control Curve (Figure’s 4, 5 and 6, respectively) which turns on or turns off the Pump based on a range of Wet Well Depths.  The overall effect is that the total flow summing all three pumps together is smoother (Figure 7 and Figure 8) and the user can simulate different pump speeds based on the same pump curve depending on which pump is currently on.

Figure 1.   Example RTC Rules and VSP Pumps in a SWMM 5 model.

Figure 2.  The Pump Curve Used for all 3 Pumps

Figure 3.  The Pump Setting for all Three Pumps

Figure 4.   Pump Control Curve for Pump 1.  The Pump has a Setting of ¼ between 0.5 and 3 feet at the node Wet Well and zero otherwise.

Figure 5.   Pump Control Curve for Pump 2.  The Pump has a Setting of 1/2 between 3 and 5 feet at the node Wet Well and zero otherwise.

 Figure 6.   Pump Control Curve for Pump 3.  The Pump has a Setting of 1 above 5 feet at the node Wet Well and zero otherwise.

 Figure 7.  The Flow in all 3 Pumps.

Figure 8.  The total flow from all three Pumps to the downstream node.

A new Map Display feature in SWMM 5.0.022 is the LID Usage parameter which shows you whether a Subcatchment has LID’s or not.   You use it by using Map Display and choosing LID Usage as the Map Display.

Here is one way to model multiple pumps between the same downstream and upstream nodes using the pump curves and the Real Time Control Rules (RTC) in SWMM 5.  Here are the steps:

 1.   Enter the data for three pumps in the browser by using the Add Pump Icon

2.   Enter three Pump Head/Flow Curves so that the 2^nd and 3^rd Pump Curves are the sum of the flows in the 1^st and 2^nd Pumps together and the sum of the flows in the 1^st, 2^nd and 3^rd respectively for the 2^nd and 3^rd Pump Curves

3.   Enter a RTC Rule in the Control Editor so that when the 1^st Pump is turned on – the 2^nd and 3^rd Pump is turned off

4.   Enter a RTC Rule in the Control Editor so that when the 2^nd  Pump is turned on – the 1^st  and 3^rd Pump is turned off

5.   Enter a RTC Rule in the Control Editor so that when the 3^rd  Pump is turned on – the 1^st and 2^nd Pump is turned off

Using these rules you can see that for the 1^st Pump turns on when the Node WetWell has a depth below 2 feet, the 2^nd Pump turns on when the Node is between a depth of 2 to 5 feet and the 3^rd Pump turns on when the Node Depth is above 5 feet.

 RULE Pump1

IF Node WetWell Depth <= 2

THEN PUMP PUMP2 STATUS = OFF

AND PUMP PUMP3 STATUS = OFF

Priority 1

RULE Pump2

IF Node WetWell Depth > 2

AND Node WetWell Depth <= 5

THEN PUMP PUMP1 STATUS = OFF

AND PUMP PUMP3 STATUS = OFF

Priority 2

RULE Pump3

IF Node WetWell Depth > 5

THEN PUMP PUMP1 STATUS = OFF

AND PUMP PUMP2 STATUS = OFF

Priority 3