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Ben F

22/01/2020 20:31:04

Hi all,

I am creating a very simple model of a catchment feeding into multiple weirs, then into a junction and head-time boundary. When creating the nodes it requires labels. I am not certain on what these labels mean. Especially for the multiple broad crested weirs I am confused. I put in what I think is the upstream label (Catchment) and the downstream label (DJunction) but it will not let me have multiple of the same type weir with the same upstream and downstream linkages. Also by doing this, I am not sure where I can actually label an individual weir (eg. PriSpillway).


Am I misunderstanding the labelling system?

How can I go about creating multiple weirs with different characteristics, linked to the same upstream and downstream nodes?


Many thanks,



Flood Modeller Support

24/01/2020 08:17:41

Best answer

Hi Ben,

I'll try and explain as best as possible. For starters, the following generic rules apply:

Boundaries and River cross sections ( conduits, interpolates, replicates) have one label each

Structures need 2 labels - one upstream and one downstream.

Junctions (and reservoirs) have as many labels as they have connections (and connectivity is detemined by the labelling). So if you had a junction whcih split into 4 branches (e.g. 4 weirs in parallel), it requires 5 labels (one for the upstream channel and one for each of the weirs it splits off into). The same (in reverse) is true when confluencing together, e.g. to your downstream boundary, so you have 4 upstream labels (which are the downstream weir labels!) and one downstream in the junction (i.e. 5 labels in this jinction as well)

Each label can only appear twice in the network.

To try and describe a simple network in terms of labelling, it'd be something like this:

QTBDY, label = Riv1

RIVER SECTION, label Riv1 (this means these two are connected)

RIVER SECTION, label Riv2 


RIVER SECTION, label Riv3 


RIVER SECTION, label Riv4 (with distance to next=0 to denote it's the end of the reach [segment])

JUNCTION: labels Riv4 Weir1u Weir2u Weir3u Weir4u

Weir #1 labels Weir1u Weir1d

Weir #2 labels Weir2u Weir2d

Weir #3 labels Weir3u Weir3d

Weir #4 labels Weir4u Weir4d

JUNCTION: labels HT_ds Weir1d Weir2d Weir3d Weir4d

HTBDY: label HT_ds

(the labels are arbitrary - call them what you want, but be descriptive :-); what matters is when the same label is given twice [and twice only], it means those two objects are connected)

Hope that helps!




Flood Modeller Support

24/01/2020 08:22:44

Just to clarify, a label can appear a maximum of twice in the network - note that those labels in the interior of the river reach only appear once (and before anyone corrects me, I know you can have remote notes, etc., as well but these are only reference nodes, and would needlessly complicate this issue ;-))

Ben F

24/01/2020 08:42:26

Wow, Kondrad. What an awesome response. Thanks so much for your help!


I see, my misunderstanding was that I was simply labeling each item such as the catchment, junction, and weir and trying to connect them with their name (which I have been able to do in other software).
Rather, the labels are to create links between each and two items that share a label are connected.


That's very useful Konrad. Thanks again


30/01/2020 09:49:00

Also from the help: It should be noted that the lateral inflow connectivity is a significant departure from normal Flood Modeller connectivity rules. 

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