Inputting ARR rainfall data
DRAINS requires rainfall data, including depth or intensity,
temporal patterns, and pre-burst rainfall depth or percentage. This section
describes the process of importing rainfall data from the Bureau of Meteorology
(BOM) website and the ARR Data Hub. Instructions for entering 1987 rainfall
data are covered in a separate topic.
Before importing ARR rainfall data, ensure that ARR v4
(2019+) Design Storm Procedures is selected in Project Options and
that a hydrological model that produces hydrographs is specified in Project
→ Hydrological Model. The Rational Method is not suitable for this process.
Then
you will need to obtain data for your location from the ARR Data Hub and the
BOM website.
To obtain the required rainfall data, download file from the
the BOM website. Save these files in a designated folder. If using the
Rational Method, only the 2016 BOM Intensity-Frequency-Duration (IFD) data
is needed, which can be entered using a simpler process.
To review or import new Rainfall data open Rainfall Data
form from the Project menu.
If the model is new, the Rainfall Data window will be
blank.
You may also want to use the following procedure to replace
an existing ensemble or add new storm details.
Then
click the Import Rainfall Depths button.
You will be requested to upload the IFD Table .csv file downloaded from the BOM
website.
Knowing where the required file is saved, you can
proceed. On clicking Yes, you will be asked to nominate a
.csv file that includes the Rainfall Depth IFD.
Then
click the Import Temporal Patterns button, it will ask you to select the
Increments Temporal Pattern .csv file you have extracted from the ARR Data Hub.
Knowing where the required files are located, you can
proceed. On clicking Yes, you will be asked to nominate a
.csv file that includes the temporal patterns.
Hint: The ARR Temporal Patterns files are provided in pairs
in a zip folder. Unzip the .zip file and you will require the one named '...
Increments.csv' to import in to DRAINS.
Pre Burst Rainfall Depths (IL-CL
If using an IL-CL based hydrological loss model, such as IL-CL, RORB, RAFTS, or WBNM hydrological models, Preburst depths are required to be imported after completing the import of the ARR storms. For more information on obtaining Preburst Rainfall data refer to the ARR Data Hub.
Clicking on Import Pre Burst Rainfall Depths at the bottom of the ARR Rainfall Ensembles window opens this window:
Follow the instructions in the above window. Be sure to RIGHT click on the Download TXT button in the data hub. Select Save Target As (or Save Link As in some browsers) to save the .txt file. Then click the Yes button in the above window. You will see an Open File dialog box where you will select the .txt file:
After importing the Download.txt file, you will be presented with the following window to select which pre-burst rainfall depths to import.
ARR Guildelines typically recommend Median Pre-Burst Depths to be utilised for most catchments in Australia, however, you must refer to any local Jurisdiction guidance on the ARR Data Hub for additional requirements.
Preburst depths and ratios are needed for the IL-CL method, but are only provided by the ARR Data Hub for storm durations of 60 minutes up to 72 hours, for events of 50% AEP through to 1% AEP.
Previously there was limited guidance from ARR on applying depths for durations less than 60 minutes, however, Table 9.6.5 of ARR 2019 Chapter 6 Book 9 indicates that the 60 minute duration should be adopted for all smaller durations. The 60 minute depth is automatically selected for all small durations.
Any durations missing from the ARR Data Hub, such as 4.5 hours, are averaged from adjoining durations.
Preburst Depths can be manually set in DRAINS' various AEP's and durations. After specifying the loss value for the applicable AEP and duration, you can toggle to the next duration and select 'Yes' to allocate the preburst loss value to all storms with the same duration and AEP
Previously there was limited guidance from ARR on applying depths for durations less than 60 minutes, however, Table 9.6.5 of ARR 2019 Chapter 6 Book 9 indicates that the 60 minute duration should be adopted for all smaller durations. The 60 minute depth is automatically selected for all small durations.
Any durations missing from the ARR Data Hub, such as 4.5 hours, are averaged from adjoining durations.
Preburst Depths can be manually set in DRAINS' various AEP's and durations. After specifying the loss value for the applicable AEP and duration, you can toggle to the next duration and select 'Yes' to allocate the preburst loss value to all storms with the same duration and AEP
Antecedent Moisture Condition (Horton - ILSAX)
If using the Horton (ILSAX) hydrological model, Antecedent Moisture Condition (AMC) values should be entered in the dialogue box.
AMC values can be manually set in DRAINS' various AEP's. After specifying the AMC value for the applicable AEP, you can toggle to the next AEP and select 'Yes' to allocate the AMC value to all storms with the same duration and AEP.
Pre-burst Depths do not apply to the Horton (ILSAX) hydrological model.
Selecting Major and Minor Storms
The rainfall data serves as a database. You will also need to define the exact storms that you need for a design or analysis from Select Major and Minor Storms from the Project menu:
After this, the rainfall data should be ready to run.
You will also be able to run with individual rainfall patterns.
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