InfoSewer Static Gravity Main Report

Note: Static Gravity Main Report

Shows steady state simulation results for all gravity mains in tabular format. The report displays one record for each gravity main in the current H2OMAP Sewer project. Gravity main report columns include the Node Identifier, Total Flow, Unpeakable Flow, Peakable Flow, Coverage Flow, Infiltration Flow, Storm Flow, Flow Type, Velocity, d/D, q/Q, Water Depth, Critical Depth, Full Flow, Coverage Count, Backwater Adjustment, Adjusted Depth and Adjusted Velocity.
The following variables are displayed on the Static Gravity Main Report in the Output Report Manager for all or selected gravity mains:

1. ID - Gravity main identifier.

2. From Node - ID of upstream node.

3. To Node - ID of downstream node.

4. Diameter - Inside pipe diameter for circular channels, in (mm).

5. Channel Depth - Maximum depth of a conduit (for non-circular channels only), in (mm).

6. Channel Width - Top/Bottom width of a conduit (for non-circular channels only), in (mm).

7. Channel Left Slope - Left side slope of a conduit (for trapezoidal and triangular channels only).

8. Channel Right Slope - Right side slope of a conduit (for trapezoidal and triangular channels only).

9. Length - Pipe length, ft (m).

10. Slope - Ratio of the change in vertical distance to the change in horizontal distance, unitless.

11. Total Flow - The summation of all flow types, flow unit.

12. Unpeakable Flow - The flow to which no peaking is applied, flow unit.

13. Peakable Flow - The flow derived based on the Federov peaking equation, flow unit.

14. Coverage Flow - The flow derived based on the Harman and Babbitt peaking equation in reference to the contributing population, flow unit.

15. Infiltration Flow - The volume of groundwater entering the sewer system from the soil through defective joints, broken or cracked pipes, improper connections, or manhole walls, flow unit.

16. Storm Flow - Peak storm load in the pipe, flow units.

17. Flow Type - Indicates if the flow is pressurized or free surface.

18. Velocity - The speed with which the water is traveling through the pipe, in ft/s (m/s).

19. d/D - The ratio of actual flow depth to the diameter of the pipe (full flow depth), unitless.

20. q/Q - The ratio of actual flow to the full flow as derived based on Manning's Equation, unitless.

21. Water Depth - The depth of water as it is flowing through the pipe, ft (m).

22. Critical Depth - The depth of water resulting when the Froude Number is equal to 1.0, ft (m).

23. Full Flow - The capacity of the pipe as evaluated based on Manning's Equation (when d/D = 1.0), flow units.

24. Coverage Count - The population parameter used in the Harman and Babbitt equations.

25. Backwater Adjustment – If the downstream head of the link is greater than the flow depth + the downstream pipe invert then the adjusted depth is one half of the sum of the water surface depth at the upstream and downstream ends of the link.

26. Adjusted Depth – The adjusted depth is the average of the upstream plus the downstream adjusted depth, where the upstream adjusted depth is the upstream head minus the upstream pipe invert elevation and the downstream adjusted depth is the downstream head minus the downstream pipe invert elevation. The adjusted depth is the minimum of the pipe diameter and the computed pipe adjusted depth.

27. Adjusted Velocity – the adjusted depth is used to calculate the wet area and adjusted velocity = flow/wet area.

See and download the full gallery on posterous

InfoSewer Static Loading Manhole Report

Note: Static Loading Manhole Report

Shows steady state simulation results for all manholes in tabular format. The report displays one record for each manhole in the current H2OMAP Sewer project. Manhole report columns include the Node Identifier, Rim Elevation, Load, Overload and Grade, surcharge status, occurrence of a hydraulic jump across the node and the unfilled and surcharged depth.

The following variables are displayed on the Static Loading Manhole Report in the Output Report Manager for all or selected manholes:

1. ID - Manhole node identifier.

2. Rim Elevation - Manhole node elevation, ft (m).

3. Base Flow - The base loading applied to the manhole (before peaking), flow units.

4. Total Flow - The calculated flow (after peaking), inserted into the manhole, flow units.

5. Storm Flow - Peak storm load at the manhole, flow units

6. Grade - Manhole node hydraulic grade for the steady state simulation, ft (m).

7. Status - Surcharge status of the manhole.

8. Hydraulic Jump – Was there a Hydraulic Jump between the incoming and outgoing pipe of the node?

9. Unfilled Depth – depth between the node Rim Elevation and the Node Grade. A zero value indicates it is full.

10. Surcharge Depth - is the difference of “The Depth of Water of Manhole” and “The Crown of the Highest Connecting Conduits”. A positive Surcharge Depth means the node water surface elevation is above the highest pipe crown, a negative depth means that the node depth is below the highest pipe crown.

RDII Import into InfoSWMM

Note: InfoSWMM and H2OMAP SWMM can import any version of the RDII Unit Hydrograph data from SWMM 5.0.001 to SWMM 5.0.021 using the Import manager command. The difference is that SWMM 5.0.013 and earlier versions had less initial abstraction data and versions after SWMM 5.0.014 had more initial abstraction data. However, the Import Manager detects the version and imports the data correctly. SWMM 5.0.013 stored 9 RTK and 3 Initial Abstraction parameters and later versions 9 RTK and 9 Initial Abstraction parameters. InfoSWMM will import any format into the current version of InfoSWMM or H20MAP SWMM, which is based on SWMM 5.0.018 but will soon be based on SWMM 5.0.021.

SWMM 5.0.001 to 5.0.013 RDII UH Data

SWMM 5.0.014 to 5.0.021 RDII UH Data

InfoSWMM and H2oMAP SWMM will have 9 RTK and 9 Initial Abstraction Parameters.

How to Import Subcatchments from GIS into InfoSWMM

Note: How to Import Subcatchments from GIS into InfoSWMM

Step 1: Add your shapefile using the Add Data command.
Step 2: Your imported shape file has no subcatchment data before we initialize the project.
Step 3: Add your subcatchment data using the GIS Exchange Cluster Import
Step 4: Now you have the Subcatchments in the DB Tables and can now calculate the area.
=====================================
Step 1: Add your shapefile using the Add Data command.


Step 2: Your imported shape file has no subcatchment data


Step 3: Add your subcatchment data using the GIS Exchange Cluster Import

Step 4: Now you have the Subcatchments in the DB Tables and can now calculate the area.

We still have to enter 1/10000 to get the right units for subcatchment area using the Auto Area Calculation under Tools preferences. You first import the shape file and then you turn on Auto Area Calculation, enter a value for the Area Scaling Factor and then use the tool Utilities, Update DB from Map, All Subcatchment to get the Subcatchment Area in hectares.

A workaround for Hydrology only models that send all subcatchment flow to the pervious area.

Note: A workaround for Hydrology only models that send all subcatchment flow to the pervious area. Briefly, v16 had a total infiltration of 14 inches in the attached model but v21 has a total infiltration of 3.5 inches. The input file uses the attached rainfall file and it routes all of the flow to the pervious area of the subcatchment. If you plot the losses in v16 and v21 you will see that the losses stop after about 30 days in v21 and continue in v16. I found that if you put in a small evaporation rate (0.01 inches/day will do) then v21 will duplicate the answers of v16. Looking at the depths in the subcatchment it seemed in v21 without evaporation that the depth in pervious area was stuck at the depression storage value.

In summary – the problem seems to be that the losses stop after the depth in the pervious area is above the depression storage unless you have evaporation to sort of kick start the infiltration losses again.

External Buildup Time Series for Water Quality Loading in SWMM 5.0.021

Note: External Buildup Time Series is now an option for Buildup. The EXT Landuse option uses a time series as the source of the water quality loading.

Source Node Tracing In InfoSWMM

Note: Source Node Tracing in InfoSWMM. Often you want to know how much flow is being contributed to the flow in a node or link from a single source node. You can use the Trace with Source Node ID option under the Quality Tab of the Run Manager to select the trace node of the analysis. The source node will have a concentration of 100 for all dry weather and wet weather inflow. This includes runoff, RDII inflow, DWF and Inflow Time Series. The InfoSWMM water quality routing routine will then be used to route the source concentration of 100 throughout the whole network. Later using the Report Manager you can view the source node concentration for any set of nodes and links in your network. For example, a concentration of 40 percent means that 40 percent of the flow in the node or link comes from your designated source node (see below).

The new features in SWMM 5.0.021

Note: The new features in SWMM 5.0.021, which really are the new features in SWMM 5.0.019, 5.0.020 and 5.0.021 because of the way in which it was released. The big structural changes were made to the subcatchment, node, groundwater, infiltration and evaporation routines so that there is better continuity between the rainfall that falls on the pervious area of a watershed, the BMP/LID’s of the subcatchment (unlimited per subcatchment), evaporation, infiltration and storage nodes/ponds/lakes. A watershed or subcatchment is now simulated in layers:

· Pervious and Impervious Area surface runoff,

· Shallow Water Aquifer for Infiltration,

· Surface ponds with evaporation and infiltration,

· BMP and LID coverage under the pervious area,

· Two layer Groundwater Aquifer for flow to canals and manholes.

How to Get the SWMM 5 GUI to recognize an already existing Report and Output File

Note: How to Get the SWMM 5 GUI to recognize an already existing Report and Output File
I found a way to see your results in SWMM 5.0.013. You need an ini file with the results flag turned on. The ini file can be very small - just three lines but once you have the Saved=1 flag on then when you open the GUI the graphs and output file icons will be turned on. An alternate method would be to have the flag automatically turned on the SWMM 5 GUI in FMAIN.PAS but you would have to recompile the GUI.
// Reset status flags
Uglobals.HasChanged := False;
Uglobals.UpdateFlag := False;
Uglobals.ResultsSaved := True; // This is normally False
Here is the three line ini file that you need.
[Results]
Saved=1
Current=1

You will have to make an ini file for each input file name and each one will have an ini file extension

The SWMM 5 GUI will
· open up your input file,
· find the results flag,
· check for existence of the rpt and out files and then
· find out the SWMM 5 version of the output file.

Solving a Bug: Processes

Solving a Bug: Processes

SWMM 5 Convergence Process

Note: Iteration Process in the SWMM 5 Dynwave.c Code

The Total flow from a Subcatchment in SWMM 5

Note: The total flow from a Subcatchment is the sum of the flow from the impervious area with and without depression storage and the pervious area with depression strorage. The same width, slope but different roughness applies to the impervious and pervious portions of the subcatchment.

The Reported Depth Variable in a Subcatchment of SWMM 5

Note: There are Three Types of Surfaces in each Subcatchment of SWMM 5. The overall depth in a subcatchment is the weighted average of the impervious without depression storage area, the impervious with depression storage area and the pervious area depth. The depths on each type of area are independent of each other.


Figure 1: The processes that occur on each type of Subcatchment Area.

Figure 2: The three independent Depths on a Subcatchment. The SWMM 5 reported Depth is the weighted average of the three depths.

SWMM 5 Subcatchment Runoff and Depth Relationship

Note: The surface runoff is a non linear function of the independent depth in both the pervious and impervious areas of the subcatchments. No surface runoff occurs until the depth over either the impervious or pervious area is greater than the respective depression storage (Figure’s 1, 2, 3 and 4).
Figure 1: Surface Runoff, Depth and Depression Storage Relationship.

How to Make a New Project INI file for InfoSewer

Note: How to Make a New Project INI file for InfoSewer
Step 1: Make a new InfoSewer Project as a New Empty Map and use the ArcGIS Default as the spatial reference.

Step 2: Save your new empty model.

Step 3: Copy your old model DB folder to the new MyEmptyModel DB folder


Step 4: Open up the mxd file MyEmptyModel and Initialize it – it should be a valid model now.

Link and Node Depth Relationship in SWMM 5

Note: The depth in a manhole or node in SWMM 5 can be higher than the depth in the connecting links if the link is surcharged. Typically the upstream link depth is equal to the upstream node depth (if there is not link offsets) and the downstream link depth is equal to the downstream node depth (if there is no offsets) until the link is surcharged and then the node surcharge depth algorithm is used in SWMM 5 and point iteration equation is used to calculate the surcharge depth in the node.

SWMM5 Groundwater Flow Components

Note: There are three sub flow components in the calculation of the groundwater flow from a SWMM 5 Subcatchment.
1^st Component: Flow = Groundwater Flow Coef. * (LowerDepth – Aquifer Bottom to Node Invert) ^ Groundwater Flow Exponent
2 ^nd Component: Flow = SurfaceWater Flow Coef. * (Aquifer Bottom to Water Surface – Aquifer Bottom to Node Invert) ^ SurfaceWater Flow Exponent
3^rd Component: Flow = SurfaceWater-Groundwater Flow Coef. * (Aquifer LowerDepth * Aquifer Bottom to Node Invert)
The total flow is the sum of all three components.

SWMM 5 Aquifer has a Saturated and Unsaturated Zone

SWMM 5 Aquifer has a Saturated and Unsaturated Zone by dickinsonre Note:  The unsaturated upper zone soil moisture varies between the initial upper zone moisture fraction to the porosity fraction for the soil.  The soil moisture content is for the SWMM5 Aquifer which can cover more than one Subcatchment in your simulation network. via Blogger http://www.swmm5.net/2013/07/swmm-5-aquifer-has-saturated-and.html

InfoSWMM and H2oMAP SWMM Map of the Maximum Surcharge Depth Over Highest Pipe Crown

Note: You can copy and paste information from the Junction Output Summary to a newly created Junction Information DB Column so that you can use Map Display to visually see the newly saved output variable.
Step 1: Run the model and then go to the Junction Summary in Report Manager and select all of the nodes in your model.

Step 2: Copy the Maximum Surcharge Height over Highest Pipe Crown Column

Step 3: Make and Insert a New Editable Field in the Junction Information Table by Pasting the information you just copied from the Junction Summary Output Column.


Step 4: Use the Map Display Command and use Existing DB as the Source and the newly created variable Junction_Surcharge_Depth

Step 5: Use the Option Show Label Properties and adjust the Font to show the maximum surcharge depth.

Step 1:  Run the model and then go to the Junction Summary in Report Manager and select all of the nodes in your model.

Step 2:  Copy the Maximum Surcharge Height over Highest Pipe Crown Column

 

Step 3:  Make and Insert a New Editable Field in the Junction Information Table by Pasting the information you just copied from the Junction Summary  Output Column.

Step 4:  Use the Map Display Command and use Existing DB as the Source and the newly created variable Junction_Surcharge_Depth

Step 5:  Use the Option Show Label Properties and adjust the Font to show the maximum surcharge depth.

via Blogger http://www.swmm5.net/2013/07/infoswmm-and-h2omap-swmm-map-of-maximum.html

InfoSWMM Batch Simulation Manager

InfoSWMM and H2OMap SWMM Batch Simulation Manager by dickinsonre Note:  How to load Scenario Output into the Report Manager of H2OMAP SWMM and InfoSWMM after they have been run in a Batch File.   via Blogger http://www.swmm5.net/2013/07/infoswmm-and-h2omap-swmm-batch.html dickinsonre | July 28, 2013 at 11:42 am | Tags: Blogger, H2oMAP SWMM, IFTTT, InfoSWMM,swmm5 | Categories: H2OMAP SWMM, InfoSWMM, swmm5 | URL: http://wp.me/pnGa9-2n1

SWMM200.COM and Related Names

Note: Domain Names that redirect to www.swmm2000.com

· WWW.SWMM2000.COM

· WWW.SWMM5.INFO

· WWW.EPASWMM.INFO

· WWW.SWMMNOTES.COM

· WWW.SWMM5.COM

· WWW.SWMM.INFO

· WWW.SWMM50.COM

· WWW.INFOSWMM.INFO

InfoSWMM and H2oMAP SWMM Output Statistics Manager

Note: You can use the Output Statistics Manager in InfoSWMM and H2OMAP SWMM to compute the mean and maximum peak flow for ALL of the links or the mean and maximum depths of all nodes in your network. Once you have calculated the mean flows using the tool you can copy them using the command Ctrl-C and paste them to a new field in the Conduit Information DB Table. The pasted mean flow from the Conduit Information table then can be mapped using Map Display.
Step 1: Run the Output Statistics Manager and decide what links and statistics you want to compute.

Step 2: Select the links you want to analyze using the pick tool.


Step 3: Copy the Mean or Average Flow value using the command Ctrl-C.

Step 4: Copy the Mean or Average Flow value to the created Mean Field in the Conduit Information DB Table.

Step 5: Map the Conduit.Mean variable from the Conduit Information DB Table.

Step 6: Display the mean flow for each link.

How to Delete Invisible InfoSWMM Subcatchments

Note: You could delete the subcatchments if you saw them on the screen. What I did here was to make a list of the subcatchments I wanted to delete; made a simple SWMM 5 import file simply containing the subcatchment names and the POLYGON field

I found a workaround that uses a part of the SWMM 5 input file but does not require you to export all of the SWMM 5 data to EPA SWMM 5. If you make a POLYGON file in this example format for all of the subcatchments you want to delete then you can import JUST the polygon data using the EPASWMM 5 import, selecting Clear All and Import. The subcatchments can then be located using the Locate command and you can easily delete the data using the delete selection icon.

I found it is best to bring in the polygon surrounding the subcatchment in the form of a triangle as this example shows.

[POLYGONS]
L33 1 1
L33 11 11
LS3 3 99
LS33 3 9
LS33 11 11
LS33 3 199

InfoSWMM 2D Version 2.0 for ArcGIS 10

MWH Soft Releases InfoSWMM 2D Version 2.0 for ArcGIS 10, Raising Bar for Urban Drainage Modeling and Simulation

Latest Release Solidifies Product as Leading GIS-centric Urban Drainage Modeling and Management Solution

Broomfield, Colorado USA, October 12, 2010

MWH Soft, a leading global innovator of wet infrastructure modeling and simulation software and technologies, today announced the worldwide availability of the V2.0 Generation of its industry-leading InfoSWMM 2D for ArcGIS 10 (Esri, Redlands, CA). InfoSWMM 2D delivers new ways to quickly build and analyze very large and comprehensive two-dimensional (2D) models that reliably simulate urban stormwater, sanitary sewers, river flooding and pollutant transport. It allows users to accurately predict the extent and duration of urban and rural flooding for comprehensive stormwater management directly within the powerful ArcGIS environment.
A fully hydrodynamic geospatial stormwater modeling and management software application, InfoSWMM 2D can be used to model the entire land phase of the hydrologic cycle as applied to urban stormwater systems. The model can perform single-event or long-term (continuous) rainfall/runoff simulations accounting for climate, soil, land use, and topographic conditions of the watershed. In addition to simulating runoff quantity, InfoSWMM 2D can reliably predict runoff quality, including buildup and washoff of pollutants from primarily urban watersheds. It also features very sophisticated Real-Time Control (RTC) schemes for the operational control and management of hydraulic structures.
Built atop ArcGIS and using exceptionally robust and efficient numerical simulation capabilities, InfoSWMM 2D seamlessly integrates advanced 1D and 2D functionalities in one environment, enabling users to model the most complex storm and combined sewer collection systems and surface flooding with incredible ease and accuracy.
When overland flows are routed through a complex urban area or highly varied terrain, the numerous elevation changes and obstacles can significantly impact results. This problem can be further complicated by the presence of sewer networks, where flows can both enter and exit the system during flood events. With InfoSWMM 2D, users can employ 1D simulation to identify the location of flooding and 2D simulation to investigate the direction and depth of flood flows in specific areas.
The full 2D free-surface shallow water equations are solved using a highly advanced finite volume method, which is particularly suitable for rapidly varying flood flows such as those through steep streets and road junctions and those associated with bank overtopping or breaching. The unparalleled 1D/2D dynamic linking capabilities of InfoSWMM 2D give engineers the unprecedented power to analyze and predict potential flood extents, depth and velocity and accurately model the interaction of surface and underground systems in an integrated 1D/2D environment. The software can also be effectively used to simulate and analyze tidal surges, dam breaks and breaches on sewer networks. The combined water level and velocity results throughout the flooded areas can be viewed as graphs, tables or animated, thematic flood maps.
“We’re deeply committed to providing a geospatial modeling experience that is both intuitive and powerful, and InfoSWMM 2D V2.0 embodies that commitment,” said Paul F. Boulos, Ph.D., Hon.D.WRE, F.ASCE, President and Chief Operating Officer of MWH Soft. “This release, following closely on May’s version 1.0, delivers major geospatial technological enhancements in short release cycles to make sure our customers are always equipped with the ultimate ArcGIS-centric decision support tool for stormwater and urban drainage systems. It greatly extends the core features of InfoSWMM, providing the most powerful and comprehensive ArcGIS-centric tool kit ever for managing the risks of urban and rural flooding.”
Pricing and Availability
Upgrade to InfoSWMM 2D V2.0 is now available worldwide by subscription to the MWH Soft Gold program. Subscription members can immediately download the new version free of charge directly from www.mwhsoft.com. The MWH Soft Subscription Program is a friendly customer support and software maintenance program that ensures the longevity and usefulness of MWH Soft products. It gives subscribers instant access to new functionality as it is developed, along with automatic software updates and upgrades. For the latest information on the MWH Soft Subscription Program, visit www.mwhsoft.com or contact your local MWH Soft Channel Partner.

Adding New View Variables To the SWMM 5 Delphi and C Code

Subject: Adding New View Variables To SWMM 5 for Villemonte Correction for Downstream Submergence. A simple seven step procedure to modify the SWMM 5 GUI Delphi Code and the SWMM 5 C code.

Step 1: Add a new View Variable to the SWMM 5 GUI Delphi code UGLOBAL.PAS

You need to add a new variable name (LINKVILLEMONTE) and increase the index number of LINKVIEWS

LINKVILLEMONTE = 48; //Output // (5.0.022 - RED)

LINKQUAL = 49; //Output // (5.0.022 - RED)

LINKVIEWS = 48; //Max. display variable index // (5.0.022 - RED)

Step 2: Add a new BaseLinkUnits description to the SWMM 5 GUI Delphi code UGLOBAL.PAS

('',''), // Villemonte Correction // (5.0.022 - RED)

('mg/L','mg/L')); // Quality

Step 3: Add a new Link View Variable SourceIndex description to the SWMM 5 GUI Delphi code Viewvars.txt

(Name: 'Villemonte Correction';

SourceIndex: 43;

DefIntervals: (25,50,75,100)),

(Name:'Quality';

SourceIndex: 44;

DefIntervals:(0.25,0.5,0.75,1.0))

);

Step 4: Add a new Link View Variable LINK_VILLEMONTE to the SWMM 5 C code in enums.h

You also need to increase the number of Link Results in enums.h for the increased number of view variables

#define MAX_LINK_RESULTS 45 // (5.0.022 - RED)

LINK_VILLEMONTE, // Villemonte Correction // (5.0.022 - RED)

LINK_QUAL}; // concentration of each pollutant

Step 5: Add a new variable to objects.h for the structure Tlink to remember the Villemonte correction at each iteration for each Weir and Orifice

double Villemonte; //(5.0.022 - RED)

} TLink;

Step 6: In the SWMM 5 LINK.C code in procedure weir_getInflow save the current iteration value of the Villemonte correction to the new structure variable

// --- apply Villemonte eqn. to correct for submergence

Link[j].Villemonte = 1.0; //(5.0.022 - RED)

Link[j].head = head; //(5.0.022 - RED)

if ( h2 > hcrest )

{

ratio = (h2 - hcrest) / (h1 - hcrest);

q1 *= pow( (1.0 - pow(ratio, weirPower[Weir[k].type])), 0.385);

if ( q2 > 0.0 )

q2 *= pow( (1.0 - pow(ratio, weirPower[VNOTCH_WEIR])), 0.385);

Link[j].Villemonte = pow( (1.0 - pow(ratio, weirPower[Weir[k].type])), 0.385); //(5.0.022 - RED)

}

Step 7: Save the value of the saved Villemonte correction in LINK.C in the procedure link_getResults so it can be read and seen in the Delphi interface

x[LINK_VILLEMONTE] = (float)Link[j].Villemonte; // (5.0.022 - RED)

Bottom and Side Outlet Orifices in SWMM 5

Note: The main difference between an Bottom and Side Outlet orifice at the same offset elevation and the same diameter is the depth at which the flow in the orifice will switch between weir flow and orifice flow. The Side Outlet orifice has Weir flow until the Orifice is full but the Bottom Orifice has Weir flow until the Critical Height which is usually shorter than the maximum depth of the orifice.

For a circular orifice the Critical Height is:

Critical Height = Orifice Discharge Coefficient / 0.414 * Orifice Opening / 4

For a rectangular orifice the Critical Height is:

Critical Height = Orifice Discharge Coefficient / 0.414 * (Orifice Opening*Width) / (2.0*(Orifice Opening+Width))

St. Venant Terms in SWMM 5

St. Venant Terms in SWMM 5 and how they change for Force Mains by dickinsonre

Note:  An explanation of the four St. Venant Terms in SWMM 5 and how they change for Force Mains.  The HGL is the water surface elevation in the upstream and downstream nodes of the link.  The HGL for a full link goes from the pipe crown elevation up to the rim elevation of the node + the surcharge depth of the node.  dq1 is calculated differently based on full or partially full force mains and gravity mains

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

            dq2 = Time Step * Awtd * (HGL) /  Link Length

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

when the force 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

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

 

via Blogger http://www.swmm5.net/2013/07/st-venant-terms-in-swmm-5-and-how-they.html

Orifice and Weir flow calculations

Note: Orifice and Weir Flow Computations

The orifice flow calculation proceeds as follows:

1. Initially and whenever the setting (i.e., the fraction opened) changes, flow coefficients for both orifice and weir behavior are computed as follows:

a. For side orifices:

Define Hcrit = h/2 where h is the opening height.

b. For bottom orifices:

i. For a circular orifice, compute area over length (i.e., circumference) as AL = h /4.

ii. For a rectangular orifice compute AL = h*w/(2*(h+w)) where w is the opening width.

iii. Compute Hcrit = Cd*AL/0.414 where Cd is the orifice discharge coefficient.

At step 1b, the critical head for the bottom orifice, where orifice flow turns into weir flow, is found by equating the result of the orifice equation to that of the weir equation

Cd*Area*sqrt(2g)*sqrt(Hcrit) = Cw*Length*sqrt(Hcrit)*Hcrit or

Hcrit = (Cd * Area) / (Cw/sqrt(2g) * Length) The value of Cw/sqrt(2g) for a sharp crested weir is 0.414.

c. Compute the flow coefficients (where A is the area of the opening):

Corif = A*sqrt(2g)*Cd

Cweir = A*sqrt(2g)*Cd*sqrt(Hcrit)

2. During flow routing, compute the degree of inlet submergence (f) and head (H) at the current time step:

a. Define:

H1 = upstream head (from node with higher head),

H2 = downstream head (from node with lower head) ,

Hcrest = elevation of bottom of opening,

Hcrown = elevation of top of opening,

Hmidpt = elevation of midpoint of opening

b. For side orifices:

f = min{1.0, (H1 - Hcrest) / (Hcrown - Hcrest)}

if f < 1.0 then H = H1 - Hcrest,

else if H2 < Hmidpt then H = H1 - Hmidpt

else H = H1 - H2

c. For bottom orifices:

if H2 > Hcrest then H = H1 - H2

else H = H1 - Hcrest

f = min{1.0, H/Hcrit}

3. Compute the flow through the orifice (Q):

if f < 1.0 then Q = Cweir*f^1.5

else Q = Corif*sqrt(H)

4: Villemonte correction

If f < 1.0 and H2 > Hcrest then:

r = (H2 - Hcrest) / (H1 - Hcrest)

Q = Q * (1 - r^1.5)^0.385

Weir Flow Computations

1. Weir head calculations

h1 = Upstream Node Depth + Upstream Invert Elevation

h2 = Downstream Node Depth + Downstream Invert Elevation

If h2 is greater than h1 then the flow is reversed and h2 = h1 and h1 = h2

Weir Crest = Upstream Node Invert Elevation + Weir Offset Depth

Head = h1 – Weir Crest

2. Center Weir flow for Transverse Weirs

Q = Cw * Weir Length * Head^3/2

3. Center Weir flow for Side Flow Weirs

Weir behaves as a transverse weir under reverse flow

Q = Cw * Weir Length * Head^3/2

And under normal flow

Q = Cw * Weir Length * Head^5/3

4. Center Weir flow for V Notch Weirs

Q = Cw * Weir Slope * Head^5/2