3. CHAPTER 3 - FLO-2D Storm Drain Data Files

3.1. FLO-2D Storm Drain Data Files

3.1.1. Input and Output File - General

This chapter describes the input and output data and their format for the FLO-2D storm drain component. The storm drain input data files can be created using any storm water user interface GUI:

  • FLO-2D QGIS plug-in,

  • EPA SWMM 5,

  • inpPINS,

  • Storm and Sanitary Analysis.

The following folders contain the storm drain model system:

  • FLO-2D PRO folder in C:\Program Files (x86). All executable program files for the FLO-2D model including pre- and post-processing and FLOPRO.exe are in this folder.

  • FLO-2D PRO documentation folder in C:\Users\Public\Documents\FLO-2D PRO Documentation (My Documents). Manuals, Handout Documents, PowerPoint Presentations, and tutorials are in this directory. Online documentation site: https://documentation.flo-2d.com/

3.1.2. Data Input Files

The FLO-2D data input files are generated by the QGIS plug-in. The QGIS plug-in creates all the storm drain data files, for more information review the FLO-2D Plugin User’s Manual document.

Typically, the FLO-2D grid system is prepared prior to developing the storm drain model. The QGIS tool creates the SWMM.inp file from a set of shapefiles (see FLO-2D Plugin User’s Manual document for more details) and pairs the inlets with grid elements. QGIS plug-in creates the associated storm drain data files needed for a FLO-2D Storm Drain simulation (SWMMFLO.DAT, SWMMOUTF.DAT and SWMMFLORT.DAT).

The following data files must be created to run a FLO-2D storm drain simulation:

3.1.2.1. CONT.DAT

This file contains the simulation control parameters:

  • Set SWMM = 1 to initiate the storm drain component, review the DATA INPUT MANUAL.DAT file for more information about this switch.

  • For no storm drain simulation, SWMM = 0 (default).

3.1.2.2. SWMM.inp

SWMM.inp is the input file that contains most of the storm drain project data. It includes pipe network geometry, inlet/outlet and junction locations, simulation control settings and hydraulic routing properties. The pipe network components in SWMM.inp must be created with QGIS plug-in or other third-party storm drain software like SWMM GUI. Table 5 lists the section data in the SWMM.inp file. Each section of the SWMM.inp file begins with a keyword.

Table 5. Sections that Enclose Data in the SWMM.inp (Rossman, 2005)

[TITLE]

Project title

[OPTIONS]

Analysis options

[REPORT]

Output reporting instructions

[FILES]

Interface file options

[JUNCTIONS]

Junction node information

[OUTFALLS]

Outfall node information

[DIVIDERS]

Flow divider node information

[STORAGE]

Storage node information

[CONDUITS]

Conduit link information

[PUMPS]

Pump link information

[ORIFICES]

Orifice link information

[WEIRS]

Weir link information

[OUTLETS]

Outlet link information

[XSECTIONS]

Conduit, orifice, and weir cross-section geometry

[TRANSECTS]

Transect geometry for conduits with irregular cross-sections

[LOSSES]

Conduit entrance/exit losses and flap valves

[CONTROLS]

Rules that control pump and regulator operation

The structure of the SWMM.inp file follows:

  • Sections appear in any arbitrary order in the input (*.inp) file. Section keywords can appear in mixed lower- and upper-case letters. Only the first four characters (plus the open bracket) are used to distinguish one keyword from another (e.g., [DIVIDERS] and [Divi] are equivalent).

  • Not all sections must be present on each project.

  • Each section can contain one or more lines of data.

  • Blank lines may appear anywhere in the file.

  • A semicolon (;) can be used to indicate that comment follows, not data. This sometimes generates reading errors in the storm drain code.

  • Data items can appear in any column of a line.

  • The data is ordered creating a tabular appearance complete with column headings.

  • When listing the format of a line of data, mandatory keywords are shown in boldface while optional items appear in parentheses.

  • A list of keywords separated by a slash (YES/NO) means that only one of the words should appear in the data line.

  • In the [OPTIONS] section, flow units can be selected as either cubic feet per second (CFS), gallons per minute (GPM), million gallons per day (MGD), cubic meters per second (CMS), liters per second, (LPS), or million liters per day (MLD). If cubic feet or gallons are chosen for flow units then US units are used for all other quantities. If cubic meters or liters are chosen, then metric units apply to all other quantities. The default flow units are CFS.

3.1.2.3. SWMMFLO.DAT

A node must have an ID starting with an ‘I’ to differentiate the inlet from a junction. Surface water discharge is only shared between nodes that have the correct ID assigned in the *.inp file. Inlets are automatically paired by the QGIS plug-into a corresponding FLO-2D grid element. The SWMMFLO.DAT file contains the inlet geometry as well as the names or numbers that identify inlet paired with the grid cell (Table 6).

Table 6. SWMMFLO.DAT Variables

                                   SWMMFLO.DAT File Variables
Line 1 to Number of Inlets (JT):
SWMMCHAR=‘D’ SWMM_JT(JT) SWMM_IDEN(JT) INTYPE(JT) SWMMlength(JT)
SWMMwidth(JT) SWMMheight(JT) SWMMcoeff(JT) FLAPGATE(JT) CURBHEIGHT(JT)

Notes:
Multiple Inlets (SWMM_IDEN(JT)) assigned to the same grid cell (SWMM_JT(JT)) constitutes a data error.
An Inlet (SWMM_IDEN(JT)) assigned to more than one grid cell (SWMM_JT(JT)) constitutes a data error.


The Table 7 outlines the required data in the SWMMFLO.DAT.

Table 7. SWMMFLO.DAT Input File Example

               SWMMFLO.DAT
D 452161 I19CP1SEMDRHRL 1 12 0 0.417 3 0 0
D 451297 I20CP1SEMDRHRL 1 4.8 0 0.417 3 0 0
D 451302 I21CP1SEMDRHRL 1 12 0 0.417 3 0 0
D 450875 I21CP2SEMDRHRL 3 6 4.4 0 3 0 0
D 441072 I22CP1SEMDRHRL 1 12 0 0.417 3 0 0
D 440649 I22CP2SEMDRHRL 3 5 3.0 0 3 0 0


Table 8 lists the variable descriptions for the SWMMFLO.DAT file:

Table 8. SWMMFLO.DAT Input Variable Descriptions

(i) = Integer variable (r) = Real variable (c) = Character

Variable

Format

Range

Description

SWMMCHAR

c

–

Character Line Identifier

SWMM_JT(JT)

i

–

Cell Grid paired with the Inlet

SWMM_IDEN(JT)

c

–

Inlet Name

INTYPE(JT)

i

1, 2, 3, 4 or 5

Type of inlet:

1: Curb opening inlet at grade

2: Curb opening inlet with sag

3: Grate (gutter) inlet with/without sag

4: Unique inlet with stage-discharge rating table

5: Manhole

SWMMlength(JT)

r

0.01 - ∞

Curb opening length for INTYPE= 1 or 2

Grate perimeter (not including curb side) for INTYPE= 3

For INTYPE = 4 (set to 0 – not needed)

Manhole perimeter for INTYPE = 5

SWMMwidth(JT)

r

0.01 - ∞

For INTYPE = 1 (set to 0 – not needed)

Curb opening sag width for INTYPE=2

Grate open area for INTYPE=3

For INTYPE = 4 (set to 0 – not needed)

Manhole flow area for INTYPE = 5

SWMMheight(JT)

r

0.01 - ∞

Curb opening height for INTYPE=1

Curb opening height for INTYPE=2

Grate sag height for INTYPE = 3

For INTYPE = 4 (set to 0 – not needed)

Surcharge depth for INTYPE=5

SWMMcoeff(JT)

r

2.8-3.3

Recommended weir coefficients are:

For INTYPE= 1,3 and 5: Range 2.8 to 3.2

For INTYPE=2: 2.3

For INTYPE = 4 (set to 0 – not needed)

FLAPGATE(JT)

i

0, 1, or 2

For INTYPE = 4:

0 = default, no flap gate, no vertical inlet opening

1 = vertical inlet opening

2 = flapgate, controls outlet node discharge

For a fake outfall INTYPE = 1, 2, 3 and 5 can be 0 or 2

CURBHEIGHT(JT)

r

0.01 - ∞

Curb height used to calculate discharge on inlets for all INTYPE

QGIS plugin creates the SWMMFLO.DAT file, review FLO-2D Plugin User’s Manual and FLO-2D Plugin Technical Reference Manual for more information.

3.1.2.4. SWMMOUTF.DAT

This file lists the outfall data, including the name of the outfall, the grid paired with the outfall and the switch (0, 1 or 2) that allow the flow to discharge to the surface (1 and 2) or out of the system (0).

QGIS plugin creates the SWMMOUTF.DAT file, review FLO-2D Plugin User’s Manual and FLO-2D Plugin Technical Reference Manual for more information.

The required data in the SWMMOUTF.DAT is shown in Table 9 and Table 10:

Table 9. SWMMOUTF.DAT Variables

               SWMMOUTF.DAT File Variables
Line 1 to Number of Outfalls (JT):
OUTF_NAME(JT) OUTF_GRID(JT) OUTF_FLO2DVOL(JT)


Table 10. SWMMOUTF.DAT Input File Example

SWMMOUTF.DAT File Example
OF1     72565   1
OF2     98863   0
OF3     97479   1
OF4     51882   1
OF5     216195  0
OF7     382089  1


Table 11 lists the variables and the description for the SWMMOUTF.DAT file:

Table 11. SWMMOUTF.DAT Input Variable Descriptions

(i) = integer variable (r) = real variable (c) = character

Variable

Format

Range

Descriptions

OUTF_NAME(JT)

c

–

Outfall name

OUTF_GRID(JT)

i

–

Cell grid paired with the outfall

OUTF_FLO2DVOL(JT)

i

0: off or

1: on

2: on

Allow discharge from the storm drain to FLO-2D.

2 is for underground outfalls with no underground elevation being imposed as a boundary condition

SWMMOUTF.DAT file should contain the list of outfalls in the same order as it appears on the SWMM.inp. When the outfall order is modified in the SWMM.inp file because an outfall node was added or deleted, the list of outfall nodes in the QGIS plug-in should be edited and the SWMMOUTF.DAT file saved. The functionality of the outfall nodes is as follows:

  • If the outfall discharge is ‘off’ the outfall will discharge off the complete model system. No discharge is returned from the storm drain to the surface water.

  • If the outfall discharge switch is ‘on’ the surface water elevation and storm drain pressure head are compared and the outfall will discharge until WSE is equal or greater than the storm drain head. The outfall flow drains back to the surface water.

  • Potential backflow into the outfall pipe will depend on the comparison of the WSEL, the storm drain pressure head and the tide gate assignment.

3.1.2.5. SWMMFLORT.DAT

The SWMMFLORT.DAT file contains a list of the rating table data or the culvert data only for those inlets that are non-typical inlets assigned as Type 4 in the storm drain system.

QGIS plugin creates the SWMMFLORT.DAT file by automatically reading the rating table from a file for each inlet type 4. Culvert data can also be added for inlets type 4. The generalized culvert equation with inlet control will be used to calculate the discharge from the surface entering the inlet. For more detailed information review the FLO-2D Plugin User’s Manual and the FLO-2D Plugin Technical Reference Manual.

The rating table is used throughout the simulation without adjustment.

The structure of a SWMMFLORT.DAT file is:

ID Grid Cell

ID Depth Discharge

ID Depth Discharge

ID Depth Discharge

…

The first pair of numbers should be zero depth and zero discharge. This is repeated from 1 to number of storm drain inlets with INTYPE= 4 (Table 12).

Table 12. SWMMFLORT.DAT Variables

           SWMMFLORT.DAT File Variables
Line 1 to Number of INTYPE 4 (JTSWMM(JT)):
SWMMCHARRT GRIDCELL SWMMType4ID
SWMMCHARRT DEPTHSWMMRT(JTSWMM(JT),K) QSWMMRT(JTSWMM(JT),K)


The required data in the SWMMFLORT.DAT is listed in Table 12 and Table 13.

Table 13. SWMMFLORT.DAT Input File Example

SWMMFLORT.DAT File Example
Rating Table
D 153076 I4-85
N 0.00 0.00
N 0.70 10.00
N 1.12 20.00
N 1.46 30.00
N 1.77 40.00
N 2.06 50.00
D 199236 I4-196
N 0.00 0.00
N 0.79 10.00
N 1.19 20.00
N 1.56 30.00
N 1.89 40.00
N 2.19 50.00
Generalized Culvert Equation
S 7545 I4-38 1.5
F 2 1 0


14 lists the description of the variables for the SWMMFLORT.DAT file.

Table 14. SWMMFLORT.DAT Input Variable Descriptions

(i) = Integer variable (r) = real variable (c) = character

Variable

Format

Range

Description

SWMMCHARRT

C

D and N

S and F

D: line with the grid cell paired with the INTYPE 4

N: line with the rating table data

S: line for generalized culvert equation

F: line for generalized culvert equation

SWMMType4ID

c

–

Name of Type 4 Inlet

GRIDCELL

i

1 - NNOD

Cell Grid paired with the INTYPE 4

DEPTHSWMMRT(JTSWMM(JT),K)

r

0.00- ∞

Depth (ft or m) for the rating table

QSWMMRT(JTSWMM(JT),K)

r

0.00- ∞

Discharge (cfs or cms) for the rating table

SWMM_JT(I)

i

1 - NNOD

Grid elements with storm drain inlets.

STRUCTNAME_ INLET

c

–

Name of the type 4 inlet. No spaces allowed in the name.

CDIAMETER(I)

r

0.00- ∞

Circular culvert diameter or box culvert height.

TYPEC(I) defines the culvert shape (ft or m).

TYPEC(I)

s

0,1

Culvert switch.

1 = rectangular 2 = circular

TYPEEEN(I)

s

0,1,2

Type of culvert entrances for a BOX:

type 1 - wingwall flare 30 to 75 degrees

type 2 - wingwall flare 90 or 15 degrees

type 3 - wingwall flare 0 degrees

Type of culvert entrances for a PIPE:

type 1 - square edge with head-

wall type 2 - socket end with headwall

type 3 - socket end projecting

CUBASE(I)

r

0.00- ∞

1 = Box culvert width

0 = No width for circular culvert.

Use CDIAMETER(I) (ft or m)

3.1.2.6. SDCLOGGING.DAT

A clogging factor was created to simulate the debris reduction of the inlet capacity.

QGIS plugin creates the SDCLOGGING.DAT file for inlet type 1,2,3,4 or 5. For more detailed information about the methodology review the FLO-2D Plugin User’s Manual and the FLO-2D Plugin Technical Reference Manual.

This option (INTYPE = 1,2,3,4 or 5 in the SWMMFLO.DAT) is assigned by the QGIS in the inlet geometry dialog box.

The SDCLOGGING.DAT file contains the data with the following format:

ID   Grid Cell     Inlet ID    Clogging Factor - Cf (%)    Time for clogging - Tc (hr)
D    2694          I1          25                                     0.50
D    2409          I2          50                                     3.25


3.1.2.7. SWMMFLODROPBOX.DAT

A file was created to enter variable dropbox surface area for inlets in the storm drain system. A minimum nodal surface area of 12.566 ft2 (~4 ft diameter) is hardwired in the SD code for drop box surface areas. A new file named SWMMFLODROPBOX.DAT can be used to enter spatially variable sizes inlet drop boxes. If this file exists, the minimum surface area is replaced by the drop box surface area entered in the file named SWMMFLODROPBOX.DAT.

Table 15. SWMMFLODROPBOX.DAT Variables

   SWMMFLO.DAT File Variables
JT= number of inlets with variable surface area

SWMM_JT(JT) SWMMDROPBOX(JT)


The Table 7 outlines the required data in the SWMMFLODROPBOX.DAT.

Table 16. SWMMFLODROPBOX.DAT Input File Example

 SWMMFLODROPBOX.DAT
452161 50.27
451297 50.27
451302 28.27
450875 19.63


Table 8 lists the variable descriptions for the SWMMFLODROPBOX.DAT file:

Table 17. SWMMFLODROPBOX.DAT Input Variable Descriptions

(i) = Integer variable (r) = Real variable (c) = Character

Variable

Format

Range

Description

SWMM_JT(JT)

i

Cell Grid paired with the Inlet

SWMMDROPBOX(JT)

r

0.01-∞

Surface area (ft2). Diameter drop box (8ft) to a surface area (50.27 ft2)

3.1.2.8. SWMM.ini

After a project is saved in the storm drain GUI, the control settings file SWMM.ini will automatically be generated. This file has the same name as the project file and the extension *.ini. It contains global settings and model output options such as map display, legend colors and intervals, object default values. If the SWMM.rpt and SWMM.out files are in the folder but the EPA SWMM is not loading the results, the user needs to enable the display of results in the storm drain GUI, the user must set the last two lines in Figure 38 as shown.

../../_images/Chapte0045.jpg

Figure 38. SWMM.ini file.

3.1.3. Output files

With the successful completion of a FLO-2D storm drain simulation, the storm drain output files will be created in the simulation folder. Table 18 list the storm drain output files and the description.

Table 18. List of the Storm Drain Data Output Files and Description

Output File

Description

SWMM.RPT

Output report file generated by the storm drain model at the end of a simulation containing the pipe routing results for each output

interval.

SWMM.OUT

Output file in a binary format that contains the storm drain results. This file is like the SWMM.RPT file and it is used by the SWMM GUI

to interactively create time series plots and tables, profile plots, and statistical analyses of the results.

SWMMQIN.OUT

Reports the inflow and return flow discharge for each storm drain inlet. The reported discharges may be different from those in the

SWMM.RPT file since the storm drain results include lateral pipe inflow and outflow.

SWMMOUTFIN.OUT

This file reports the outfall hydrographs for return flow to the surface water system. This file lists the grid or channel element in the first

line followed by the time and discharge pairs.

FPRIMELEV.OUT

This output file reports the differences in elevation between the rim/invert elevation in the SWMM.inp file and the FLO-2D grid

element elevation. This file should be reviewed to evaluate the elevations representing the inlet reference.

StormDrain_ERROR.CHK

This output file reports the storm drain error and warning messages. They were removed from the ERROR.CHK file.

SDManholePopUp.OUT

This output file reports the information for the manhole popping in the storm drain system. The information reported is manhole name,

time of occurrence, elevation comparison for the popping.

ManholePop.OUT

This output file reports the information for the manhole popping in the storm drain system in a table. The information reported is

X coordinate, Y coordinate, grid cell, manhole name, time of occurrence, pressure head, rim + surcharge depth, WSE.

FPLAIN_SDElev.RGH

Changes in elevation (FPRIMELEV.OUT) are reported to the FPLAIN_SDElev.RGH file.

Replace the FPLAIN.DAT file to apply the changes to

the next simulation

TOPO_SDElev.RGH

Changes in elevation (FPRIMELEV.OUT) are reported in the TOPO_SDElev.RGH. Replace the TOPO.DAT file to apply the changes to

the next simulation.

UndergOUTFALLS.CHK

This output file reports the underground outfalls, the invert elevation of the outfall, the grid cell elevation, and the difference between

them.

SUMMARY.OUT

Volume conservation, run time, and final disposition of the volumes between the model components are reported in this file.

The storm drain volume is reported as:

  1. Storm Drain Inflow in the inflow volume that flows from surface water to storm drain system through inlets and outfalls

    (compare total w/SWMM.rpt Wet Weather Inflow):

    • SURFACE TO STORM DRAIN SYSTEM THROUGH INLETS: Volume that flows from surface water to storm drain network

      through the inlets.

    • SURFACE TO STORM DRAIN THROUGH OUTFALLS: Volume that flows from surface water to storm drain network through

      the outfalls as backwater.

    • DIRECT INFLOW RECEIVED AT INLETS: volume that enters the system from outside of the domain.

    • TOTAL INFLOW (compare w/SWMM.rpt Wet Weather Inflow).

  2. Storm Drain Outflow from Outfalls is the volume that leaves the storm drain system through outfalls (compare total w/SWMM.rpt

    External Outflow):

    • STORM DRAIN TO SURFACE THROUGH OUTFALLS: Volume that flows from the storm drain to the surface

      water through the outfalls. Only those outfalls that were turned ‘on’ in the SWMMOUTF.DAT will discharge the volume back

      to the surface layer.

    • STORM DRAIN OUTFALL (OFF SYSTEM): Volume that flows off the storm drain through the outfalls.

      Only those outfalls that were turned ‘off’ in the SWMMOUTF.DAT will discharge the volume off the storm drain system.

    • TOTAL OUTFLOW (compare w/SWMM.rpt External Outflow)

  3. Storm Drain Return Flow to Surface

    • STORM DRAIN RETURN FLOW TO SURFACE THROUGH INLETS: Volume that returns to the surface water through inlets.

    • TOTAL STORM DRAIN RETURN FLOW + OUTFLOW: Volume that returns to the surface water from the storm drain network

      plus outflow.

      Return volume is possible when the storm drain pressure head is greater than both the RIM elevation and the FLO-2D water

      surface elevation in the inlet grid element.

  4. STORM DRAIN SYSTEM STORAGE: volume in the pipe system at the end of the simulation. This volume is extracted from the

    swmm.RPT file.

  5. STORM DRAIN RETURN FLOW + OUTFLOW + STORAGE

  6. STORM DRAIN MASS BALANCE: mass balance volume conservation calculated as:

    Total Inflow - Total Outflow - Total Storm Drain Return Flow

    • Storm Drain System Storage

SUMMARY.OUT
  1. Extracted from Storm Drain File (swmm.RPT):

    • WET WEATHER INFLOW: Compare with Storm Drain Inflow.

    • EXTERNAL INFLOW: Other node inflows in addition to any surface runoff such as direct inflows as user-defined time series,

      dry weather inflows that are continuous inflows as base flows, and rainfall dependent infiltration/inflow (RDII).

    • EXTERNAL OUTFLOW: Compare with Storm Drain Outflow from Outfalls.

    • Return Flow to Surface: Compare with STORM DRAIN RETURN FLOW TO SURFACE THROUGH INLETS.

    • Total Storm Drain Storage (nodes + links): Sum of the storage.

    • Continuity Error (%)

CHVOLUME.OUT

This file reports the channel flow distribution including inflow, outflow, overbank flow, infiltration losses and volume conservation.

This includes the volumes for channel outflow to the storm drain and channel inflow from the storm drain.

ERROR.CHK

This FLO-2D file contains input data error warnings and messages for the surface model. This file should be reviewed for messages after

each simulation.