12d Advanced Stormwater
12d Advanced Stormwater
12d Advanced Stormwater
Course Notes
CIVIL AND
SURVEYING SOFTWARE
THE 12D PERSPECTIVE
Disclaimer
12d Model is supplied without any express or implied warranties whatsoever.
No warranty of fitness for a particular purpose is offered.
No liabilities in respect of engineering details and quantities produced by 12d Model are
accepted.
Every effort has been taken to ensure that the advice given in these notes and the program 12d
Model is correct, however, no warranty is expressed or implied by 12d Solutions.
Copyright 12d Solutions Pty Limited 2006
2.0
3.0
4.0
5.0
6.0
7.0
7.1
7.2
7.3
8.0
8.1
8.2
9.0
9.1
9.2
9.3
10.0
10.1
10.2
10.3
10.4
10.5
10.6
10.7
11.0
11.1
11.2
11.3
12.0
13.0
14.0
14.1
14.2
14.3
14.4
15.0
15.1
16.0
16.1
16.2
16.3
17.0
use the powerful 12d drainage network editor to avoid service clashes, grade pipes,
align obverts, minimise depth and many other design tools,
transfer data to and from electronic spreadsheets to enable the user to easily review
the data and add user defined data to the 12d pipe network. This data may include
such data as pipe bedding types and trench width,
create pit layout schedules to export to spreadsheets or word processors for final formatting.
produce long section drainage profiles including HGL data, flows, invert levels, service crossings
create plan drawings with pipe sizes, flows, manhole symbols, linestyles for pipe
sizes, design parameters for manhole and pipes and user defined data
This manual, the Advanced Stormwater Design Course, is intended to describe the more
advanced features 12d model drainage and discuss the customisation of the package. This will
include
s
design or evaluate the drainage system using 12d Drainage or create input files for the
XP SWMM/RAT2000, Micro drainage, Drains and PCdrain drainage design packages,
read the output from the drainage design packages (automatic if using 12d Drainage),
update the drainage network and store the hydraulic data, such as hgl (hydraulic grade
line) levels, peak pipe flows and pipe capacities,
----------------------------- BEGIN APPLY TEMPLATE REPORT -----------------------------apply template to string report string
E
tin
design
separation
10.000
left template 375
right template 375
cut volumes and areas are negative
fill volumes and areas are positive
chainage- ------sectional information------ ------intermediate information------------- ---cut area --fill area ------------ ----cut vol ---fill vol
0.000
-1.434
0.000
0.550
-1.367
0.000
10.000
-1.642
0.000
20.000
-1.416
0.000
21.313
-1.393
0.000
-0.771
0.000
-14.222
0.000
-15.293
0.000
-1.845
0.000
0.000
-0.794
21.863
-1.493
total cut
total fill
balance
ie excess of cut over fill
0.000
0.000
-0.771
0.000
-0.771
-14.992
0.000
-14.992
-30.286
0.000
-30.286
-32.130
0.000
-32.130
-32.924
0.000
-32.924
0.000
0.000
-32.924
0.000
-32.924
32.924
If a tin is created from these strings then volumes by depth can be determined using Design=>Volumes=>Exact=>Tin to tin
Usage
Access this panel from the menu selection
Design => Drainage => Reports => Excavation Quantities
Type
Drainage model
input box
Defaults
Pop-Up
Model to contain all of the pit and pipe network to be worked on.
Strings model
model box
model box
input box
tin box
real box
colour box
Sections generated from the templates will be assigned this colour (strings colours are defined in the
templates)
Clean section/strings model
tick box
tick box
Template are run from manhole centre to centre if this is not selected. The templates stop at the edge of
the manhole if selected. This is often selected with the following option Use obvert templates.
Use obvert templates
tick box
Templates must be named with the prefix obvert. i.e. obvert 300. The template is still run along the
invert of the pipe but the user now has a section set of templates that can be used to create a tin on
top of the pipe as well as below.
The fields and buttons used in this panel have the following functions.
Field Description
Type
Choice
Defaults
Pop-Up
usually the entire model is selected but view is also available for combining models
MH config file
file box
This file specifies the types and depth ranges for the manholes. Details of this file are contained below.
file box
This file specifies the types and depth ranges for the pipes. Details of this file are contained below.
HC config file
file box
This file specifies the types and depth ranges for the house connections. Details of this file are contained below.
HC pit config file
file box
This file specifies the types and depth ranges for the HC pits. Details of this file are contained below.
HC jump ups file
file box
This file specifies the types and depth ranges for the house connections jump ups. Details of this file are
contained below.
Report file
file box
tick box
the depth ranges for the manhole/pipe/house connections are defined in the *.4d files. Selecting this
option will cause the depth ranges in the file to be printed even if there are no manhole/pipe/house connections in these depth ranges (zero quantity values will be shown).
Report types
tick box
Selecting this option will cause the manhole/pipe/house connection types used in the model types to be
listed (even if quantities are not requested in the *.4d files). Since this is a complete of the type used in
the model, the list informs the user what types have not been included in the quantity calculation.
Count
button
button
The *.4d files listed above are contained in the 12d library directory. Each line is the file performs a count (count lines). No items are counted twice. Therefore, if an item is counted its type
and then a count line is found the wild card is used for the type, the type already counted will not
be included in the count.
The format for a count line is three or four values (space delimited) per line. Size is optional.
<type (from drainage.4d)>
<ending depth>
Notes:
COVER"
COVER"
COVER"
COVER"
0.0 1.6
1.5 3.0
3.0 999.9 // this is expected to be zero
-999.0 0.0 // trap errors
Manhole Quantities
====================================
CONC
CONC
CONC
CONC
COVER
COVER
COVER
COVER
*
*
*
0.00
1.60
3.00
-999.0
1.60
3.00
999.9
0.0
13
1
0
0
16.506
1.510
0.000
0.000
0.00 1.60
1.60 3.00
3.00 999.9
0
0
0
0.000
0.000
0.000
Types Used
---------CONC COVER
Diameters Used
---------1.100
Export pipe diameters and inverts is generally select for existing systems only. If your design program will set invert levels and pipe sizes then turn this tick box off for new systems.Some design
programs will require initial inverts and pipe sizes. In this case this box should be selected on the
first export.
Export default catchment/pit parameters is generally selected for the first export. For subsequent
exports turn this selection off and then only the catchment areas (if the model is supplied above) will
be exported.
Select Export
Select Spreadsheet clipboard
7.1.1 Options
The Spreadsheet Options section allows the user to define the amount of data exported.
All Data: All of the 12d drainage string data and the user defined attributes will be exported to the
clipboard in a tab delimited format. The 12d data names and the user defined attribute names will
appear at the top of the spreadsheets columns.
ILSAX: For the ILSAX program, the spreadsheet column headings will change depending on the
pipe and catchment indicators (P2 card) and the inlet type (P3 card). Therefore, use the ILSAX
pipe editor macro to set up one pit/catchment for the type of data you wish to enter. Now when
you export the pipe network data the column headings will include the names of the relevant
parameters.
User defined below: The Customised list file name is used to define the drainage values, their
order and format you desire.
The customised list file is a text file where each line contains a drainage variable or a spreadsheet
IO command (blank lines are ignored unless preceded by the header command). The spreadsheet
IO commands available are:
header
blank
pipe data
pit data
variable name
factor
After creating your customised list file, select Options again and change the Preset Output field to
User Defined below and enter the new customised list file name that you saved above. Select Set
then Finish and finally Copy to put the formatted data onto the clipboard.
The data can be pasted into a spreadsheet program for checking or additional formatting.
CUSTOM FORMATED DATA MIGHT NOT BE PASTED BACK INTO 12d!
The data must be in the 12d drainage spreadsheet format to be read into 12d.
Caution with manhole names in the form 1-1 or 1/1. Some spreadsheets will interpret these values as
dates. If you use these formats for your manhole names you will have to paste command them in
once, format the columns that contain the manholes names as text data and then paste the information in again.
One final word on using the copy/paste commands in the Microsoft Excel program. The Paste Special command using the Skip Blanks option will allow you to copy a large block of 12d data (with
blanks in it) on top your data so that your data is preserved where it coincides with the blanks. To use
this option paste the data into a blank spreadsheet and then select copy again. The Paste special
Select Import
Select the Spreadsheet clipboard
format.
The file field is ignored.
Tab delimited, 12d drainage spreadsheet format or from to format data must be on the clipboard in order to update a 12d drainage model or create a new model. These format are described
below.
7.1.3 Updating an Existing Model
The data usually is generated by 12d using the Export option, pasted into a spreadsheet and then
copied back to the clipboard so that 12d can be updated.
Duplicate Definitions
Strings Variables such as direction are may be defined for numerous manholes on the same string.
Searching in a top down direction through the file, the last definition found for the string will be set.
Invert levels may be set via pipe data or pit data or combined. It is recommended that the user only
use one method and not combine them. Both are exported so delete the ones you are not going to use.
The variables are processed from left to right, so if duplicate definitions of an invert level or found
the right most data will be set.
Key Points
1. Set the manhole types to names that signify the inlet type in the program you are exporting to
(Type on the Pit->Main tab).
2. Check that your grate level is correct (Setout z + Setout to grate offset)
3. Mark the manhole as a On grade or SAG inlet (Inlet data on the Pit->Main tab). On grade inlets
capture the water as it passes the inlet while SAG inlet trap the water flowing in from all directions.
4. Draw an bypass flow string in the direction of flow so that it passes within 1 manhole diameter of
the inlet. When bypass flow strings join they must join within 1 manhole diameter of a manhole.
If flooded with calculations are to be done later, the bypass flow string must have a unique name
and the string should located in the flow channel.
Enter the model name in the Bypass flow model field on the Global->Utility Models tab.
5. Ensure a setout string is linked to the inlet so that the road grade may be calculated in its direction.
If road crossfall is needed then the centre string is also required. These strings are specified using
the Road design file on the Global->Utility Models tab.
6. Press the Set Pit Details button. Road grades, crossfalls, ponding depths and bypass pits will now
be found in the Inlet data section on the Pit->Main tab. The bypass data may be verified on the
Pit-Main tab of the Network Editor.
Starting at the upstream end. LB select an insertion point and MB or press return to accept the
selection. Continue this until you reach the end of the flow path. The string will not be shown in
the new linestyle until the screen is redrawn. Press ESC to finish drawing the string. MB on the
plan view title area to redraw the screen. The correct linestyle will now appear.
If you reach a sag pit location you may terminate the string or continue defining the bypass flow
path for a surcharging event out of the sag location.
12d adds verification strings in the construction model to confirm the locations where the road and
crossfall have been measured. To check these strings add the construction model to the plan view.
The following image shows a close up of the verification strings at a pit.
The blue line indicates where the road grade was measured and the red line indicates where the road
cross fall was measured.
These are 3d super strings and therefore you may profile them in the section view. With the grades
toggled on (check under Toggle) you can verify the slopes.
Important Notes
1. Pits with no pit type specified will not be processed by the overflow routine and the inlet
capacity will be set to 100%.
2. For pits with no road design string specified, the inlet capacity will be set to 100%.
3. If no bypass flow string is supplied for a pit, the inlet capacity is set to 100%.
4. If you have a problem with the inlet capacity factors (Drains Version 1 and ILSAX), check the
calculated crossfall and grade.
manhole names and types, easting and northing data with surface levels
optional - crossing services - level, size and location along the pipes
optional - bypass manholes, road grades and SAG inlet ponding depths
Manhole type
The 12d manhole type is transferred to the structure type in PCdrain. These names must match those
specified in the PCdrain Inlet charts selected (Data=>Inlet charts). Select the desired inlet charts
BEFORE importing the interchange file.
12d manhole types with an S in the name are treated by 12d and PCdrain as a SAG inlet pit. 12d
will strip off all characters after the S before adding the ponding depth. If a catchment string in set
#1 is available for the SAG pit then the ponding depth will be calculated.The12d manhole type will
remain unchanged. A typical example would be a manhole type 1TC with the sag tick box on
would become 1TC0.100 if a ponding depth of 0.1 was calculated.
Bypass Flow
When a catchment string is specified for the manhole, the maximum depth before bypass flow commences is calculated. The lowest point on the catchment string is determined by draping it onto the
drainage strings tin. The maximum depth before bypass is calculated manhole setout level less the
setout to grate offset less the lowest point on the catchment string.
PCdrain differentiates between manholes (no surface inflow) and gully pits via the 12d manhole
type. The bypass flow strings can only be drawn within 1 manhole diameter of the gully pits. Keep
the bypass flow strings away from the PCdrain manholes.
Catchments
Again, since PCdrain differentiates between inlets and manholes (using the 12d manhole type),
ensure that catchments are only drawn for gully inlet and NOT manholes.
Select the Run button and the interface file will be created.
2. Launch the PCdrain for Windows program. If you have a project set up with the design parameters, rainfall data, inlet charts and gutter profiles then open it now and skip to step 8. Otherwise continue with step 5.
3. The Design Parameters can be set as desired with the menu selection
Data=>Design Parameters.
4. Select the rainfall data using the Data=>Rainfall menu selection.
5. Select the inlet charts using the Data=>Inlet Charts menu selection. The manhole types specified in 12d must be included in these settings. More - PCdrain to 12d pit converter
6. At least one gutter profile in PCdrain needs to be defined. These are set through the menu
selection Data=>Gutter Profiles. The default gutter section name (Road ID) from 12d is 4d
and therefore it is recommended you create a profile with this name and your own description.
If you have changed the profile names in 12d (through the spreadsheet interface or the
Attribute editor) these new profile names will have to exist in PCdrain.
7. Save this file now so that you can retrieve it later if required. It can be used as a starting template for new jobs.
8. File=>Import from the menu. Select the file exported in step 1. The information from 12d
may be viewed by selecting Data=>Network and then selecting the desired tabs.
9. The HGL level and the pipe elevation at the outlet should be set using the menu selection
PCdrain
12d editor
12d attribute
initial export
value
Kw
not available
kw
12d ku value
Minor Coef
c minor pervious
default
Major Coef
c major pervious
default
Minor Coef2
c minor pervious2
default
Major Coef2
c major pervious2
default
Tc overrider
tc minor pervious
default
Length of
overland flow
catchment length
pervious
default
Grade of
overland flow
catchment grade
pervious
default
Length of gutter
flow
catchment length
impervious
default
Grade of gutter
flow
catchment grade
impervious
default
Road XSections
left
not available
4d
Road XSections
right
not available
4d
Select Import
Select PCdrain Int (Windows)
from the drop down list.
Select the output file name you
created in PCdrain.
manhole names and types, easting and northing data with surface levels
optional - bypass manholes, road grades/crossfalls and SAG Inlet Calculations (ponding volumes and depths). Pit family selection using road grade and crossfall data.
optional - composite catchment area create from three12d areas per manhole
Data is copied from 12d to the Windows clipboard and then pasted into Drains (Edit=>Paste data
from spreadsheet). 12d can not delete any objects in Drains, it can only add and update.
The Drains menu selection Run=>Design is used to design the network. Once the drainage network
has been designed in Drains the updated design data (Edit=>Copy data to spreadsheet) and/or the
hydraulic results (Edit=>Copy results to spreadsheet) are sent back to 12d via the clipboard.
Always copy the DATA to 12d before the results as the results are deleted inside 12d with every
update of the data!
A demonstration version of the Drains program is included on the 12d distribution CD in the directory
Other_Software\Drains
The version is limited in the number of pits allowed.
All Ca se s
dra ina ge .4d
Pipe type entries
Dra ins da ta ba se
Pipe type
Dra ins da ta ba se
Pit famly
Every Drains file begins with a default database and uses that database for the life of the project.
This database must by synchronised with the drainage.4d file in 12d to ensure the Drains pit families, pit sizes, pipe types and overflow route types.
The following 5 steps will help ensure 12d is synchronised with Drains. More details are given in
the sections below.
review the Drains pit families list to identify the character (usually a comma or -) that
separates the pit group from the road data and then enter it in the Pit group separator
field.
select Create drainage.4d. The Drains database dump file is copied to the 12d working folder and a drainage.4d file is created in the 12d working folder.
4)Restart 12d
From the 12d menu select Project->Restart.
Key Points
1. Select Read Drains database (12d will search the usual locations for the Drains database)
2. Review the Drains pit families list to identify the pit group separator and then enter it in the Pit
group separator field. PRESS THE ENTER KEY!
3. Check the 12d pit groups and if they are acceptable select Create drainage.4d.
The Details
Defaults
Pop-Up
You must update this file from Drains before each use of this panel. Inside Drains select
Project=>Overflow Route database. Then select OK and then YES. This will cause Drains to export
the database to the file Drains Connection Data.txt.
Selecting Enter in this field or selecting Read Drains database will cause the panel to search for the
database dump in the folders C:\Program Files\Drains\Program and C:\Program
Files\Drains\Demo\Program. If the Drains program is installed in another folder then you must
browse for the file. After reading the file choice boxes below will be populated. Drains Connection
Data.txt will be copied into the 12d working folder.
Drainage.4d
file
drainage.4d
The drainage.4d will be created in the 12d working folder unless otherwise specified. It will only be
used for 12d projects in this folder.
Pit families
choice
These are the Drains pit families that will be exported to the drainage.4d file. The 12d pit groups will
be created from this list.
Pipe type
choice
These are the Drains pipe types that will be exported to the drainage.4d file.
Overflow Route Shapeschoice
These are the Drains Route Shapes and are for information only.
Pit group separatorinput
These characters will be used to remove the road grade crossfall data from the Pit families above. The
data before this character will become the 12d pit groups. Press Enter or select Read Drains
database to create a new list of 12d pit groups.
12d pit groups
choice
These are created from the Pit family list above by deleting all text after the Pit group separator. This
should delete all of the road grade and crossfall information from the pit group names.
Read Drains databasebutton
Searches for the Drains database (see general description above) and populates the choices fields.
Create drainage.4dbutton
Create a local copy of the drainage.4d file.
On selecting the Edit drainage.4d option, the Edit drainage.4d panel is displayed.
Select the Find button to search the 12d path for the
current drainage.4d file. Select the More info button
and then Edit to edit the file.
The drainage.4d file contains Manhole and Pipe commands. 12d also uses the Manhole commands to
specify a manhole group by using the prefix group. Details follow.
Headwalls
The manhole type Headwall (case sensitive for Drains) is reserved for the inlet headwall for a conduit. Drains does not use this for an outlet headwall.
If the inlet type is On Grade or there is no bypass pit, the setout z level + the setout to grate offset is
exported as the Drains surface level. If the Inlet type is marked as a SAG pit then the surface level
will be calculated from the low point on the catchment string (catchment set #1). The ponding depth
will often be negative in this case. Also see SAG Inlet Calculations.
//4d
0,
1,
0,
0,
0.0,
1.0
0,
2,
0,
0,
0.0,
1.0
//4d
0,
4,
0,
0,
0.0,
1.0
//4d
0,
6,
0,
0,
0.0,
1.0
//4d
0,
8,
0,
0,
0.0,
1.0
//4d
1,
1,
0,
0,
0.0,
1.0
1,
3,
0,
0,
0.0,
1.0
1,
5,
0,
0,
0.0,
1.0
1,
7,
0,
0,
0.0,
1.0
1,
9,
0,
0,
0.0,
1.0
3,
1,
0,
0,
0.0,
1.0
3,
3,
0,
0,
0.0,
1.0
3,
5,
0,
0,
0.0,
1.0
3,
7,
0,
0,
0.0,
1.0
3,
9,
0,
0,
0.0,
1.0
slope
//4d
slope
//4d
slope
//4d
slope
//4d
slope
//4d
slope
//4d
slope
//4d
slope
//4d
slope
//4d
slope
}
The Drains pit family names must match the names in the last column EXACTLY!
Pipe Types
The pipe type selected in 12d must exist in the pipe database inside Drains. Simple 2 for class 2
or RCP do not exist in Drains.
10.4 Setting the Overflow Route, the Pit and Pipe types
Position of option on menu:
On selecting the Drainage IO Defaults option, the Drainage IO Defaults panel is displayed.
The routine changes ALL of your manhole and pipe types in a model to a single value. If you have changed
your drainage.4d file after creating you drainage network, the manhole and pipe types you originally selected
may no longer be valid (i.e. in the drainage.4d file).
Field Description Type
Defaults
Pop-Up
Drains
Drains, PCdrain
choice
Set all pipe types will set all pipes in the model to this value
12d manhole typeschoice
Set all pit types will set all manholes in the model to this value
Default pit groupschoice
manhole definitions in the drainage.4d file that have group as a prefix are included.
Default road shapechoice
type the desired name or if using Drains select the desired shape from the Drains Overflow route shapes.
Drains Tab
the pipe types are retrieved from the last Drains database dump. Changing this value will update the 12
pipe types above.
Drains Overflow Route Shapeschoice
the overflow route shapes are retrieved from the last Drains database dump. Changing this value will
update the Default road shape above.
Set all pipe types button
all pipe types in model are set to this value
Set all pit types button
all pit types in model are set to this value
Set defaults
button
the defaults for the Drains Overflow Route Shapes and 12d pit group are set
Finish
button
Results
Drains exports the maximum data from all of the rainfall events analysed. Therefore, ensure you analyse only the rainfall events desired before coping the results to the clipboard. To verify the data that
is being sent to 12d, copy the data into a spreadsheet so you can view it there first. The pit sizes
selected in Drains will be stored in 12d as the manhole type. Therefore the pit sizes in Drains should
exist as manhole types in the drainage.4d file. If pit families are changed in Drains the pit group in
12d will be updated by search for the pit family in the drainage.4d file.
In addition to the results, the following input data is read back into the 12d model so that it may be
exported back to RATHGL in the future (if required). 100% of your RATHGL data is not included
in the XPX formats and the contents of the XPX file will depend upon your design mode. Therefore, use caution if you read an XPX file into an existing RATHGL model and check your data
once inside RATHGL.
1. From within RAT-HGL, produce an XPX file for 12d to read by selecting Special=>Export
They may not be defined for the pit you are editing. Not found will be displayed in the Data field
if the pit does not have that attribute defined.
To change the value for the attribute
enter the new value in the data field. If
the attribute does not exist, deleting the
not found text and adding data will create it. The message on the right will be
displayed whenever you are creating a
new attribute.
Usage
This option is accessed from the menu selection
Design => Drainage-Sewer => Plots => Plan Annotations
The fields and buttons used in this panel have the following functions.
Field Description
Type
file box
Defaults
Pop-Up
Optional - no dpf is required. The default settings will create a schematic drainage drawing. A custom
dpf may be selected if desired.
Load design details from
model box
tick box
when selected the string colour will be used for the string name (to be used for DWG/DXF export using
map files)
Plot
button
button
used to locate plot parameter input boxes using Version 5 plot parameter names
IMPORTANT! to turn off any data change the text height to zero.
Now select
Tins->Null->by angle/length
Select the tin created above for Tin to
null.
Enter a small value for Length.
Select Null.
The tin will now only exist on top of the pipe and it is ready to use for hatching.
From the Plot parameter file field select a drainage longsection ppf from the library and then select
Read.
In the View to load details from field select the section view you have setup for the drainage long
section.
Now select Hatching cut/fill
Now select the + beside the Hatching cut/fill and then select fill.
Use set # is entered as 1. Fill separation, hatch angle, colour and linestyle selected as desired.
Draw sides of tin, Draw original tin and Draw new tin are not required unless you want these
extra line in the drawing.
Select Plot and add the plot model drainage LS plot1 onto a PLAN view to preview the drawing.
3,
3,
3,
3,
3,
1,
3,
5,
7,
9,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0.495,
0.270,
0.290,
0.400,
0.330,
.819
.568
.599
.727
.649
//4d
//4d
//4d
//4d
//4d
5,
5,
5,
5,
5,
1,
3,
5,
7,
9,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0.540,
0.480,
0.460,
0.450,
0.420,
.793
.747
.744
.729
.704
Sc1
,
3.0,
Sc2
,
3.0,
Sl1
,
0.5,
Sl2
lintel length,
max depth
0.5,
3,
.150
Discharge Event
Minor ARI
Maximum flow event analysed
Maximum flow event analysed
First return period analysed
The user defines the length of these sections and the interval at which they are to be spaced. 12d
calculates the normal flow depth interpolating the pit approach and bypass flows from the hydrology models (ILSAX, Drains, PC Drains or RAT HGL). The cross sections are taken perpendicular
to the flow line and the slope is for the normal depth calculations is determined using the distance
along the flow line and the change in elevation between the two lowest points in the primary flow
channel. The flow line need not intersect the low points on the section but the flow line does mark
the primary flow channel. If the depth of the flow exceeds the banks of the primary channel, then
all adjacent flow channels will be considered as active flow area.
Trim sections at levee is used to create a cross section that stops at the crest on either side of the
flow channel. A levee point is the crest in the cross section found as you move away from the flow
line location. If a levee point is encountered then the section is trimmed here.
Levee tolerance is the amount the cross section needs to drop as you move away from the centre line
in order to call this local crest a levee.
VxD warning limit is the velocity times depth limit that when exceeded will cause a flooded width
Summary Tables
The hydraulic calculations and warning messages are stored as string attributes on the flooded
width bars. If these attributes are exported to a spreadsheet via the clipboard a summary table my
be created. To copy these attributes to the clipboard select
File IO->User->String attributes-properties to/from clipboard
sag pit
must be equal to 1.
catchment model id
catchment string id
The maximum storage volume is read from the drainage pit attribute "overflow volume". This
may be entered manually using the Attribute Editor or it will be created when data is read from the
drainage design programs Drains or XP SWMM design programs.
This routine locates the lowest point on the catchment string by draping the string on the tin specified and adds the overflow limit specified to this value. This becomes the overflow limit.
The volume at this level is calculated and the compared to the overflow volume read from the
user defined attribute.If the overflow volume is less than the volume in the catchment then the
routine iterates to find the flood level for the overflow volume.
If the overflow volume is greater than the volume in the catchment, the results depend on the Use
overflow limit tick box.
If the box is selected, the overflow limit (calculated above) is reported at the flood level in the
catchment.
If the tick box is not selected the routine iterates to find the flood level where the storage equals
the overflow volume read. This option allows the user to see the maximum flood level should the
catchment low point become blocked.
See Also
Drainage overview
Usage
This panel is accessed from the menu selection Design => Drainage Sewer => More=>Calc pit
overflow areas
The fields and buttons used in this panel have the following functions.
Field Description
Type
Drainage model
model box
Defaults
Pop-Up
all pits in this model that have a non zero "overflow volume" and "sag pit" set to 1 will be processed
Flood limits model
model box
tin box
ground surface tin used to calculate the volumes and flood limits
Flood limits colour
colour box
tick box
if selected all strings in the Flood limits model will be deleted before the calculations commence.
Use overflow limit
tick box
if the elevation calculated from the storage volume is higher than the lowest point on the catchment string
then the allowable surcharge value below will be added to the lowest point on the catchment string and
this elevation will be used to determine the flooding limits
Allowable surcharge
real box
this value is used only if Use overflow limit is ticked. Its purpose is described in the field above.
Process
button
button