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Replace existing XSec geometry with new data created using the Cross Section Generator

Posted 02/07/2019 11:50 by tom

Last post 02/07/2019 12:25

1 reply

We have a river diversion that is being designed in 3D CAD.  We have a 1D FM model of the river.   The river design will change as the scheme progresses. I want to be able to update the river cross sections in the flood model based on the 3D surface from CAD.  We can import the CAD surface of the river diversion into FM as an asc file, and using the existing dat file (renamed as a sec file) we can use the Cross Section Generator tool to create new cross sections based on the imported asc surface at the same locations as the existing cross sections. All good so far.  I havent found a way of being able to update the cross section geometry in the original model with the new cross sections without having to manually paste the cross section XY data back into the original model one cross section at a time. Is there a way?  I certainly dont want to have to delete all the original cross sections and copy in the new ones as new nodes, as the model is a bit too complex to contemplate doing that...  Suggestions very welcome.

Linking Rectangular Culvert to Arch Bridge

Posted 30/05/2019 15:06 by garret

Last post 03/06/2019 09:36

7 replies


I'd really appreciate some help with a 1D build problem I'm having.

This is my first attempt at creating my own Flood Modeller project and the network is quite simple with a few cross-sections and two structures. The first structure is a sprung arch bridge and the model runs fine for this. However, what I need to do is connect a c. 74m long rectangular culvert immediately downstream of the bridge. The problem I'm having is that there is something wrong with how I'm connecting it.

What I've got in the network is a replicate section named "Arch" > bridge named "Arch" > Culvert Inlet ("CulvertIn") > Rectangular Culvert ("Culvertu") > Rectangular Culvert (Culvertd) > Culvert Outlet ("CulvertOut"). After the CulvertOut there's two cross-sections and the downstream boundary.

The zzd file says:

  Datafile line     82:
 *** warning W2229 *** at label: CulvertIn
 Value of trash screen height is set
 to 0; areas will be calculated using  piezometric head.
number of labels compiled from units =   8
number of labels in data file at line 2 =   9
  2. label(node) CulvertOut(007) occurs only once (i.e. is not connected) - this is not permitted
  3. label(node) Culvertd(009) occurs only once (i.e. is not connected) - this is not permitted
 Datafile line    152:
 *** error   E1057 *** at label:

 Number of errors found in node labels is   3
 stopped in reader

I don't have any remote node labels and I'm wondering whether this is where I'm going wrong?


Thank you for reading this. Any ideas will be gratefully received.

(partial) data file cannot end with a section with nonzero chainage

Posted 10/05/2019 16:36 by A FloodModeller

Last post 10/05/2019 16:43

1 reply

I have a baseline 1D network that I want to use as the basis for a number of simulations. For some of the simulations I want to use different cross section profiles for selected river sections. I did not want to create multiple copies of my baseline model to just incorporate a few changed sections, therefore I created a series of event files with extension “ied” (note these equally could have extension “sec”). I then set up each of my 1D simulations to use my baseline network together with one of my event files incorporating adjusted river cross sections. However, when I ran any of these simulations they always failed immediately and I got the same error message; “(partial) data file cannot end with a section with nonzero chainage”. Please can anyone advise what the issue with my model might be?

Generic Rainfall Runoff unit - Transformation model

Posted 04/05/2019 09:17 by danielcb12

Last post 04/07/2019 11:11

1 reply

Hi all, 

I am using the generic rainfall/runoff unit for the input into a small network I have created. For transformation, I am using the 'watershed lag method'. Is anybody able to clarify the flow length for me? I assumed it was the average distance from any part of the catchment to the channel? 


Many Thanks

TIN nodes are missing in ZZN files

Posted 20/02/2019 10:22 by Siripen Songprasit

Last post 20/02/2019 17:08

9 replies


I'm creating TIN using Tin Creator. When loading the results, there are TIN nodes missing. I looked up in Help 'How to View 1D Modelled Results' and paragraph 3-ii says:

"...In certain circumstances (when cross-sections used to generate the TIN cross over) pseudo-points will be added to the TIN. These points will not have node references, so users will need to refer the pseudo points to two nearby nodes. This is done by left-clicking on the pseudo point, and then left clicking on the relevant nearby node whilst holding down the left control key (to assign the first nearby node) and repeating the process for whilst holding down the left shift key in place of the control key (for the second node). Experience of using pseudo points has shown that they can cause erroneous flood extents, and thus it may be advisable to make sure that cross-sections do not cross over."

I've tried to assign node references in TIN Creator but it doesn't seem to work. I've also made sure cross sections don't cross over, but I still get missing nodes. 

What's the best way to overcome this issue?

Kind regards,



Orifice Aperture Shape

Posted 31/01/2019 17:01 by Max W

Last post 04/07/2019 11:19

2 replies

Hello folks,


As of FM v 4.3 orifices can now be circular! However, it appears the help guide has not (yet) been updated.

First question, does anyone have any experience using them over rectangular culverts? We seem to get pretty different interactions depending on if the culverts are rectangular or circular and wanted to make sure the circular orifice unit wasn't some sort of 'beta test'.

Secondly, does anyone have any input of the 'spikeyness' of the change in flow of circular orifice units over rectangular when the mode of flow changes from orifice to drowned/free weir flow?

Lastly, as there's no guide, could someone point me towards the different equations used by the various modes?



Cross section superimpose

Posted 17/07/2018 09:53 by ghimireb

Last post 17/07/2018 10:55

1 reply

Hi, I was trying to overlay an old cross-section that underwent a design evolution. Is there any way to overlay it onto the new section as a line only so as not to obscure the plot ?  Any suggestion would be highly appreciated.

Renaming Model Nodes

Posted 14/02/2018 15:10 by Cian.Buckley

Last post 16/02/2018 15:52

3 replies

Hi All,

I have a model built using a number of different survey sets from different survey providers. The various surveyors have used different cross section naming conventions therefore the node labels within the model are inconsistent. I would like to change the names of all nodes so they are consistent, ideally using the following naming convention;

“Abbreviation of river name_ Chainage from downstream boundary or confluence if the river is a tributary (m)” for example a node on the River Thames, 600m upstream of the downstream boundary would have the node label “Tha_0600”  

The model contains of over 500 nodes so I would like to change the labels as efficiently as possible while ensuring any links/ junctions remain intact. It is a 1D/2D Tuflow model therefore the point shape file linking to the flood modeller nodes will need to be renamed accordingly for the model to run.

Has anyone any suggestions on how best to make these changes?

Any suggestions would be much appreciated.



Connecting steep watercourses

Posted 27/10/2017 11:32 by Monica Macias Jimenez

Last post 27/10/2017 12:43

5 replies

Hi modellers,

I am having trouble joining two watercourses which perfectly run by themselves. The model is only in 1D. However, when trying joining them I have a drop of 5.6m from the tributary into the main watercourse. I find it massive but that is what was provided by the surveyors.

I tried putting a manual slot in the last cross section of the tributary to match the invert level but the model crashes in the same way as without it. The problem is that water is increasing in the tributary and it makes the model to crash because of glasswalling. Decreasing the inflow at the top of the tributary slightly help but not much. I have modified the IC manually and played with the advance parameters in order to get better IC but I have the feeling that is more of a schematisation problem. I am duplicating the cross section in the main watercourse where I am joing the tributary and just using a junction. I know junctions maintain water levels the same in all units joined and I took that into account as well. Anything I am missing or any recommendation of what to do in this case?

Thank you very much in advance,


1D Results Flood Map

Posted 16/10/2017 17:56 by Sarah

Last post 17/10/2017 17:01

1 reply

Hi, I'm trying to create a flood map based on my 1D results. In order to do so I have created a cross section polyline (to create the TIN). However; numerous cross sections do not have complete georeference data and therefore my cross section polyline its completely out. In this situation how can I add the missing georeference? Or what can I do to get round this? If I create a TIN based on the current georeferenced cross sections I end up with big gaps in the overall flood map.


Georeferencing nodes in the map view when joining two models

Posted 08/09/2017 09:42 by Natalie

Last post 08/09/2017 10:22

1 reply


I have created two separate models in Flood Modeller (main channel and tributary) which are both georeferenced and the nodes appear in the correct place on the map view. However, when I copied across the nodes from tributary model to connect to main channel model the tributary nodes (i.e. the copied nodes) do not appear in the correct place in the map view. I'm not sure why this is because the nodes have all retained their georeferencing and when I drag the dat file (of the two models joined together) into the GIS layers window the cross-sections all appear in the correct location.

Can you please advise how I can shift the tributary nodes into the correct location on the map view?

Thank you,


Bridge cross sections and distances

Posted 23/08/2017 11:39 by Nick

Last post 23/08/2017 13:26

2 replies


I am trying to establish the correct method for positioning cross sections upstream and downstream of bridge units.

Given that the cross section upstream of the bridge must have a 'distance to next cross section' set to 0, is it important to locate this cross section near the toe of the bridge?

For instance, the nearest surveyed cross section I have is 40m upstream of the bridge.  Should I either;

1) 'replicate' this cross section and place it near the upstream toe of the bridge; or

2) leave the cross section where it is, set the 'distance to next cross section' to 0 and add the lost 40m to the previous upstream section.

Thanks in advance


Cross Sections invalid

Posted 02/08/2017 06:42 by Chulani

Last post 15/08/2017 16:03

1 reply

Hi all,

When i was extending CS upto bank levels the cross sections were unloaded from the  layer panel of the FM interface sudenly. 
When i try to import the my network to layer again, error message appears saying "cross Sections May be invalid". 
Please help me to fix this problem.

Merging ASC files

Posted 30/06/2017 18:59 by Ph. Schilb.

Last post 21/07/2017 17:23

6 replies

Hello, I am currently working on an Estuary flooding simulation, a rather large area. Sadly, I am not able to gain one large ASC file with the needed topographical data. but multiple. Now my question is how do I merge these files together into one. So, when I create the cross-section on the river they are continues through the neighbouring sections.


Thank you in advanced!

Displaying WL in routing cross sections

Posted 27/06/2017 08:26 by Monica Macias Jimenez

Last post 30/06/2017 13:44

3 replies

 Hi everyone,

I am working on a model which is only based on routing cross sections (Muskingum X) and I would like to see my water level displayed within my cross sections or the long plot. It seems is not possible and I only can see the cross sections but not able to display maximum water level on them. Is there a trick to see if the water is in bank? It would be helpful also to be able to do an animation or a long plot.




Adding Bridge Length

Posted 29/05/2017 06:39 by Ankita

Last post 29/06/2017 18:21

1 reply


I would advise not to model as a duel bridge as you will likely be overestimating the afflux. In order to retain the correct channel length (i.e. to account for the bridge length) you can either increase the distance to next of the upstream or downstream cross section by 5m or equally split it between them both.


georeferencing networks

Posted 17/05/2017 13:17 by Sofia Theofanidi

Last post 19/05/2017 13:36

3 replies

hi all, 

I have a very big 1D network (above 1000 nodes) which has aready been created. I am trying to select some the nodes (export as network) to create a smaller network to georeference but it does not work (I am using flood modeller free). I have also tried to georeference the nodes using txt file (easting,northing, nodea) but in the end only about 200 of them are georeferenced (the other ones dont). I have tried also to use georeference all cross sections and I have also tried to follow the steps at youtube and forum tutorials but still nothing. 

However, I've noticed that in my model the ones that can be georeferenced have letters at their labels (eg SBL 1.111 or RT 4.08) comparing to the ones that do not contain any letters at their labels (eg 1.05 or 2.180).

Does labeling affect the georeference of the network? By the way the model I am using has been created with a much older version (isis 2.3) and I am working with Flood Modeller Free 4.2. or 4.0

Many thanks for your  help

Best regards


Mapping 1D Modelled Floodplains

Posted 07/04/2017 12:03 by NP

Last post 18/05/2017 12:19

3 replies


I need to create floodplain maps/extents from the 1 D model which includes a main channel and floodplain represented by multiple reservoir units. Appreciate your reponse.



Modelling of informal woody dams

Posted 26/02/2017 05:51 by maspiers

Last post 06/03/2017 10:58

3 replies

We're trying to represent a reach which contains some informal woody dams - build ups of branches and woody debris which impede flow but may get dislodged by higher flows. Is there any guidance on modelling these?

Recalculate distance to next error

Posted 17/02/2017 17:32 by Addison.Jobe

Last post 20/02/2017 11:18

1 reply

I have created several models in flood modeller by importing shape files for cross section lines from ArcMap. However when creating my last couple of models the "recalculate distacne to next" tool under Additional 1-D model tools will no longer work after I have already created my sections.sec. I have tried this step on multiple computers in the same lab at my university, but always with the same problem of Flood Modeller not responding a couple of seconds after I start the chainage calculation. How do I fix the program or fix my model to insure this tool will work the next time?

Thank You,


Reservoir unit

Posted 17/02/2017 09:56 by P McAteer

Last post 17/02/2017 10:08

3 replies


I have two questions:

1. How can I set the initial water level in a reservoir unit?

2. Can I connect a reservoir unit directly to a channel section?

Many thanks

Modelling channel spill

Posted 13/02/2017 09:54 by P McAteer

Last post 20/02/2017 10:34

5 replies

Good morning.

I am trying to model a river with 12m long overflow weir along the channel embankment leading to an small lake immediately south of the river. The arrangement I have come up is to connect the upstream spill (Sp1u) to a (single) river section S7, and the downstream spill (Sp1d) to the lake – unfortunately the variable flow run no flow across the weir, even when flow level in the channel is well above the level of the weir. Clearly I am doing something wrong – can anyone offer advice as to how I should model this?

Many thanks






gxy reference

Posted 09/02/2017 10:07 by NP

Last post 10/02/2017 14:24

7 replies


I have built a 1D model without any georeferences. what would be the best way to appropriately/quickly georeference it now that i have got nearly 250 nodes model? 

many thanks

Deactivation Markers

Posted 27/01/2017 10:14 by KevH

Last post 17/11/2017 18:37

3 replies

Hi Bob

Unfortunately I have experienced this same issue in my model using Version 4.3 frown

Is there a way to fix this other than going back to my previous model iteration (prior to extension) and copying the newly generated data into each river section?

Thanks, Jen

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