Zero FLow

[Deirdre Kelly]

Hi there. I am running a fairly basic model in the Rangelands region of WA with no streamflow data using ARR2016 IFD’s and producing zero flow. I assume this is because my losses are too high but I have kept them low to start, IL = 20, CL = 5.
I assume it may have something to do with the temporal patterns. See supplied screenshots. How do I apply the point temporal pattern? Help would be much appreciated. Thanks.

Attachments:

You must be logged in to view attached files.

[Benson Liu]

Hi Deirdre,

Based on the pictures, yes the flow is 0 because the losses are too high. While temporal pattern may play a part in the flow being 0, this is most probably due to the design rainfall being applied being low. The rainfall at the top of the plots shows that the rainfall you have is being wiped out by the losses you have assigned. While a different, peakier temporal pattern may make the rainfall more intense it is unlikely to change the results too much when the rainfall depths are so low.

The point temporal patterns can be applied the same way as the areal temporal patterns, you just need to load in and select the point temporal patterns CSV. When you download the areal temporal patterns from the ARR data hub, there will be an option just next to it to also download the point temporal patterns CSV.

Kind regards,

Benson

[Deirdre Kelly]

Thanks Benson. That helps alot.
I have 2 more questions if thats okay?
1. I have a feeling the main data hub file.txt I am using might be wrong and the ARF’s are not being read properly. I downloaded the info from the txt download at the bottom of the page (see provided image). I assume this is correct? and then I converted it to a text file. But an error comes up saying it cant read it.
2. Also wondering I need to replace the areal reduction factor value (see image)?
3. Last question is whether I need to tick the regional losses box and the ARF’s box if I am using variable losses I have defined (due to none being available in the data hub)? (See image)

Attachments:

You must be logged in to view attached files.

[Deirdre Kelly]

And regarding the point temporal patterns. Is it possible they are not available for this catchment due to the lack of data? There is no option in the data hub to select point temporal patterns (see image).
Thanks again. Appreciate the help.

Attachments:

You must be logged in to view attached files.

[Benson Liu]

Hi Deirdre,

The download link above the areal temporal patterns are the point temporal patterns, for whatever reason they do not have the ‘point’ label.

With the data hub text file, I’m unsure why RORB cannot read the text file, the way you describe downloading the data is correct. What is the exact error that pops up?

For area reduction factors (ARFs), if the outlet of the RORB model is the point of interest then you do not need to replace the value. ARFs are calculated based on catchment area, by default RORB will take the total catchment area in the model and use this for the calculation. If your point of interest you are trying to get design flows for is not the outlet (say half way through the model) then this is where you would input the catchment area to your point of interest so RORB will calculate and apply the correct ARFs.

The regional losses tick box only pre-fills the losses with the regional losses from the data hub text file. If the data hub doesn’t have it, the pre-filled values will be 0. Either way you have the opportunity to put in your own values before you run the simulation. The ARF tick box just means it will use the coefficients in the data hub text file to calculate ARFs. The only reason you would not tick this box is if you wish to use different coefficients to calculate ARFs. In this case you would then need to press the ‘Edit Coeff’ button and put in your own values.

Kind regards,

Benson

[Deirdre Kelly]

Hi Benson. Thankyou for kindly stepping me through my silly questions. All makes sense now and model is making sense. Flows are getting close to what I anticipated.
Have a great day :)

[Author]

Posts