Storm Data Dialog Box

The Storm Data dialog box allows you to create, edit, and delete the Storm Data definitions that will make up the Global Storm Data that is applied to the model.

A storm data definition can be created in any of the following ways, both from within the Storm Data dialog box:

You can manually create a storm data definition by clicking the New button and selecting one of the five methods in the Storm Data dialog.
You can import storm data definitions from a text file.
You can import a storm data definition from the associated Storm Data Group engineering library. To do so Click the Engineering Libraries button and select Import From Library in the Storm Data dialog.

The dialog box contains a list pane on the left, a tabbed input data area on the upper right, and a graph pane on the lower right, and includes the following controls:

	New	Creates a new storm data definition that uses an automatically created label.
	Delete	Deletes the currently highlighted storm data definition.
	Rename	Lets you rename the currently highlighted storm data definition.
	Report	Lets you generate a preformatted report that contains the input data associated with the currently highlighted storm data definition.
	Import	Opens a browse dialog, allowing you to select a text file from which to import storm definition data.
	Engineering Libraries	Allows you to synchronize in or out from an engineering library, import from or export to an engineering library, or connect to to an engineering library.

The fields and controls that appear in the tabbed area depend on which definition type is currently highlighted in the list pane on the left.

Time-Depth

When editing a definition of the Time-Depth definition type, the tabbed area of the dialog contains the following controls:

Storm Data Input Tab

Add Return Event: Opens a submenu containing the following commands:

New Return Event: Opens the New Storm Data Settings dialog, allowing you to define the parameters for the return event.
Add Return Event from Storm Data: Opens the Storm Data Engineering Library, allowing you to select a predefined storm data to use.
Add Return Event from Dimensionless Curve: Opens the Dimensionless Rainfall Curve Engineering Library, allowing you to select a predefined dimensionless curve to use.
Add Return Event from IDF: Opens the Build Rainfall from IDF Storm Group dialog, allowing you to set the parameters for the IDF storm data.

Delete: Removes the currently highlighted storm from the list.

Edit: Allows you to edit the currently highlighted storm data.

Notes Tab

This tab contains a text field that allows you to enter descriptive notes that will be associated with the currently highlighted storm data definition.

Library Tab

This tab displays information about the storm data definition that is currently highlighted in the list pane. If the storm data definition is derived from an engineering library, the synchronization details can be found here. If the storm data definition was created manually for this model, the synchronization details will display the message Orphan (local), indicating that the storm data definition was not derived from a library entry.

Time-Intensity

When editing a definition of the Time-Intensity definition type, the tabbed area of the dialog contains the following controls:

Storm Data Input Tab

Add Return Event: Opens a submenu containing the following commands:

New Return Event: Opens the New Storm Data Settings dialog, allowing you to define the parameters for the return event.
Add Return Event from Storm Data: Opens the Storm Data Engineering Library, allowing you to select a predefined storm data to use.
Add Return Event from Dimensionless Curve: Opens the Dimensionless Rainfall Curve Engineering Library, allowing you to select a predefined dimensionless curve to use.
Add Return Event from Chicago Storm Data: Opens the New Return Event from Chicago Storm Data dialog allowing you to enter Chicago storm information to generate a hyetograph. (see Calculating a Hyetogrph from Chicago Storm Data.

Delete: Removes the currently highlighted storm from the list.

Edit: Allows you to edit the currently highlighted storm data.

Notes Tab

This tab contains a text field that allows you to enter descriptive notes that will be associated with the currently highlighted storm data definition.

Library Tab

User Defined IDF Table

When you create a definition of the User Defined IDF Table definition type, an empty IDF Table is created with a single Duration Column and no Return Period rows. You can add or remove Durations and Return Periods using the buttons above the table.

When editing a definition of the User Defined IDF Table definition type, the tabbed area of the dialog contains the following controls:

Storm Data Input Tab

Add/Remove Return Periods: Opens a submenu containing the following commands:

Delete Return Period—Use the Delete command to remove the currently highlighted column from the table.

Add/Remove Durations: Opens a submenu containing the following commands:

Delete Duration—Use the Delete command to remove the currently highlighted row from the table.

Notes Tab

This tab contains a text field that allows you to enter descriptive notes that will be associated with the currently highlighted storm data definition.

Library Tab

Hydro-35

When editing a definition of the Hydro-35 definition type, the tabbed area of the dialog contains the following controls:

Storm Data Input Tab

Data Tables: When you create a definition of the Hydro-35 definition type, the dialog will display 2 tables in the tabbed area:

Notes Tab

This tab contains a text field that allows you to enter descriptive notes that will be associated with the currently highlighted storm data definition.

Library Tab

IDF Table Equation

The IDF Table Equation definition type calculates the storm data using the following equation:

Where

i = rainfall intensity
D = rainfall duration
Rp = return period
a, b, m, n = rainfall equation coefficients

When editing a definition of the IDF Table Equation type, the tabbed area of the dialog contains the following controls:

Storm Data Input Tab

Equation Duration Unit: Specify the unit to be used for duration (D) value in the equation.

Equation Intensity Unit: Specify the unit to be used for intensity (i) value in the equation.

a: Specify the value to be used for the a coefficient in the equation.

m: Specify the value to be used for the m coefficient in the equation.

b: Specify the value to be used for the b coefficient in the equation.

n: Specify the value to be used for the n coefficient in the equation.

Results Table: This table displays the calculated rainfall intensity values for the 2, 3, 5, 10, 25, 50, 100, 200, and 500 year return periods at durations of 5, 10, 15, 20, 30, 40, 50, 60, 80, 100, and 120 minutes.

Notes Tab

This tab contains a text field that allows you to enter descriptive notes that will be associated with the currently highlighted storm data definition.

Library Tab

IDF Curve Equation

The IDF Table Equation definition type calculates the storm data using the following equation:

Where

i = rainfall intensity
D = rainfall duration
a, b, n = rainfall equation coefficients

When editing a definition of the IDF Table Equation type, the tabbed area of the dialog contains the following controls:

Storm Data Input Tab

Equation Duration Unit: Specify the unit to be used for duration (D) value in the equation.

Equation Intensity Unit: Specify the unit to be used for intensity (i) value in the equation.

Add Return Event Button: Adds another Return Period row to the table. When you click this button an Add Return Period dialog appears, allowing you to specify the return period for the new row.

Remove Return Event Button: Removes the currently highlighted Return Period row from the table.

a (log): Specify the value to be used for the a coefficient in the equation for the associated return period.

b: Specify the value to be used for the b coefficient in the equation for the associated return period.

n: Specify the value to be used for the n coefficient in the equation for the associated return period.

Results Table: This table displays the calculated rainfall intensity values for the each of the return periods in the table at durations of 5, 10, 15, 20, 30, 40, 50, 60, 80, 100, and 120 minutes.

Notes Tab

This tab contains a text field that allows you to enter descriptive notes that will be associated with the currently highlighted storm data definition.

Library Tab

IDF Polynomial Log Equation

The IDF Polynomial Log Equation definition type calculates the storm data using the following equation:

Where

i = rainfall intensity

D= rainfall duration

a, b, c, d = rainfall equation coefficients

When editing a definition of the IDF Polynomial Log Equation type, the tabbed area of the dialog contains the following controls:

Storm Data Input Tab

Equation Duration Unit: Specify the unit to be used for duration (D) value in the equation.

Equation Intensity Unit: Specify the unit to be used for intensity (i) value in the equation.

Add Return Event Button: Adds another Return Period row to the table. When you click this button an Add Return Period dialog appears, allowing you to specify the return period for the new row.

Remove Return Event Button: Removes the currently highlighted Return Period row from the table.

a (log): Specify the value to be used for the a coefficient in the equation for the associated return period.

b (log): Specify the value to be used for the b coefficient in the equation for the associated return period.

c (log): Specify the value to be used for the c coefficient in the equation for the associated return period.

d (log): Specify the value to be used for the d coefficient in the equation for the associated return period.

Results Table: This table displays the calculated rainfall intensity values for the each of the return periods in the table at durations of 5, 10, 15, 20, 30, 40, 50, 60, 80, 100, and 120 minutes.

Notes Tab

This tab contains a text field that allows you to enter descriptive notes that will be associated with the currently highlighted storm data definition.

Library Tab

To Import a comma or space delimited ASCII text file:

Click Import in the Storm Data dialog, and select the location and name of the file containing the rainfall table in ASCII format to import. You may see a prompt warning you that any existing storm data will be overwritten - if you do not want this, click Cancel.
Select Open to import the ASCII text file, or Cancel to exit without saving the changes. When importing an ASCII text file, the following format is assumed: The first line of the imported text file contains the return periods. The first entry in each succeeding line of the file contains the storm duration. All other entries represent rainfall intensities, which are assumed to be in the current display unit (i.e. in/hr, mm/hr, etc.).

An example in comma separated format is given below for return periods of 1, 2, 5, 10, 20, 50 and 100 years, and durations of 5, 15, 30 and 60 minutes):

1 , 2 , 5 , 10 , 20 , 50 , 100 5 , 47.0 , 63 , 87 , 103 , 125 , 157 , 183 15 , 29.7 , 39.5 , 54 , 63 , 76 , 95 , 110 30 , 20.8 , 27.5 , 37.1 , 43.5 , 52 , 64 , 75 60 , 14.0 , 18.4 , 24.5 , 28.6 , 34.0 , 41.8 , 48.1

Rain File

When editing a definition of the Rain File type, the tabbed area of the dialog contains the following controls:

Storm Data Input Tab

Rain File: Allows you to select the desired SWMM rain file.

Rain Data File Type: Allows you to select the type of data stored in the selected rain file.

Rain Units: Allows you to select the unit for the data in the selected rain file.

Rain File Storm Data Table: Click the New button to add a row to the table; click Delete to remove the currently highlighted row from the table. The table consists of the following columns:

Label: The label for the storm data.
Station ID: The station ID for the storm data.
Time Interval: The time interval for the storm data.
Snow Catch Factor: Allows you to enter the SWMM snow catch factor.

Notes Tab

This tab contains a text field that allows you to enter descriptive notes that will be associated with the currently highlighted storm data definition.

Library Tab

Flood Studies Report (United Kingdom)

When editing a definition of the Flood Studies Report definition type, the tabbed area of the dialog contains the following controls:

UK Standard Location: Select England and Wales or Scotland and Northern Ireland.
R: The rainfall depth value.
M5-60: This is the expected depth of rainfall in millimetres (mm) from a storm lasting 60 minutes (1 hour) with a return period of 5 years

Notes Tab

This tab contains a text field that allows you to enter descriptive notes that will be associated with the currently highlighted storm data definition.

Library Tab

Australian Rainfall and Runoff (2016)

The Australian Rainfall and Runoff 2016 data can only be entered by importing a custom CSV file downloaded from the Australian Government Bureau of Meteorology.

After entering the requested data and accepting the terms, use the Download as CSV link above the map preview.

If you leave the unit set to depth (mm), the data will automatically be converted to intensity when imported. It is recommended that you switch the unit to intensity to avoid any conversion issues.

Once you have a CSV file available, create a new Australian Rainfall and Runoff 2016 storm group. Then click on the Import button and select the CSV file to import. The data is then read and displayed read-only in the table.

When the data is imported, a matrix is created based on the information found at

http://www.bom.gov.au/water/designRainfalls/ifd/ifd-faq.shtml#sec1q5

. This preserves the data in the original CSV file for easy understanding of the data. The column headers will display the ARI with the original mapping in parentheses. For example, the original column header of "63.2%" that is included in IDF Design Rainfall Depth (mm) data is displayed in the column header as "1ARI (63.2% AEP)". For additional information, review the link provided above.

The import process looks for certain information in the CSV file to verify it is valid. This information includes the first line which is the copyright line.

In addition, the 3^rd line of the file is used to determine the format and how to parse the data into IDF curves. This line can be one of the following six:

IFD Design Rainfall Depth (mm)
IFD Design Rainfall Intensity (mm/h)
Very Frequent Design Rainfall Depth (mm)
Very Frequent Design Rainfall Intensity (mm/h)
Rare Design Rainfall Depth (mm)
Rare Design Rainfall Intensity (mm/h)

The following 5 lines are used as notes. See the Notes section below for additional information.

If any of these lines are modified then the file is considered invalid.

The Australian Rainfall and Runoff 2016 CSV file is incompatible with the User Defined IDF Table import function.

Notes

After successfully importing data from a CSV file, the notes are set to the summary information found in the file. This includes the requested and actual coordinates and the data type that was imported.

e.g.:

IFD Design Rainfall Depth (mm)

Issued:,02 February 2018

Location

Label:,Rundle Mall

Requested coordinate:,Latitude,-34.907099,Longitude,138.5915

Nearest grid cell:,Latitude,34.9125(S),Longitude,138.5875(E)

The purpose is to provide a historical record and provenance of the data. It is recommended that you do not change this information.

Library Tab

Flood Estimation Handbook (United Kingdom)

The FEH presents a rainfall depth-duration-frequency (DDF) method. This replaces the Location, M5-60, and ratio r values which are described in the Flood Studies Report (FSR), and used in the Wallingford Procedure. The FEH retains the FSR rainfall profile and Areal Reduction Factor procedures.

The FEH analysis considered durations of 1, 2, 6 and 12 hours and 1, 2, 4 and 8 days, and return periods from 2 to 1000 years. It includes a CD-ROM with the 6 parameters defined on 1km grid covering the UK.

The formulae used to obtain rainfall depths from the 1 km point DDF values are:

lnR = (cy + d1) lnD + ey + f for D = <= 12 hours

lnR = lnR12 + (cy + d2) (lnD – ln12) for 12 = D = <= 48 hours

lnR = lnR48 + (cy + d3) (lnD – ln48) for D = > 48 hours

Where:

y = -ln(-ln(1-1/T))

R = rainfall depth (mm)

D = duration (hours)

T = return period (years)

And c, d1, d2, d3, e, f are parameters

And d1, d2, and d3 are for the duration ranges <12, 12-48, and >48 hours respectively.

The Langbein formula is applied to return periods between one year and less than five years.

1-1/TAM = exp(1-1/TPOT)

Where:

T = return period

When creating a new FEH storm event group, default return periods and durations are used.

The following return periods are used (Years): 1.58, 5, 10, 20, 25, 30, 50, 75 and 100. The user can also add additional return periods. However, you cannot remove any return periods.

The following durations are used (Hours): ½, 1, 2, 3, 4, 6, 8, 10, 12, 16

The following durations are used (Days): 1, 1.5, 2, 3, 4, 5, 6, 7, 8

The depth is calculated given the parameters and then converted to intensity in mm/h and then converted and stored in in/h.

Notes Tab

The notes tab provides a way for the user to write notes about the storm event group.

Library Tab

Generate Storm Data Dialog Box

Build Rainfall from IDF Storm Group Dialog Box

New Storm Data Settings Dialog Box

Time Settings Dialog Box

Storm Data Dialog Box

Rainfall Curve Import Settings Dialog Box

Rainfall Curve Dictionary Dialog Box

Rational Method IDF Curve Dialog Box

New Return Event from Chicago Storm Data

Parent topic: Stormwater Flow