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surcharged culvert long section view

Posted 20/11/2015 09:32 by mark1111

Last post 24/11/2015 03:38

2 replies

when modelling a culvert and one looks at its long section, can one explain when the culvert is surcharged, the long section provides a waterlevel above the soffit level of the culvert for the length of the culvert to its outlet? regards


Matrix Singular Error message

Posted 11/11/2014 16:19 by matthew Scott 1978

No replies yet

Hello Currently running a very large ISIS model (12000 nodes). Model simulation gets to over 100 hours before the model fails. Error message is as follows: Model time 149.9694 hrs: *** error E1196 *** at label: matrix numerically singular. iflag = -2 stopped in solve dongle licence released successfully I have looked at relaxing the Pivotal Choice parameter and matrix dummy coefficient values, which have improved matters but not solved the problem entirely. Adjusting the global matrix dummy coefficient is ineffective. Any help would be great Cheers

"event file not found"

Posted 20/02/2014 09:44 by DavidW

Last post 12/03/2014 13:01

2 replies

Hi, I have just started using ISIS. I have basic model build but when I try and run it I get following message: [b]© 2013 CH2M Hill and others ISIS 1D Revision: Date: 13/11/13 Seeking licence for ISIS 1D... ISIS FREE (status code 0) Simulations limited to 250 nodes; Hydraulics/hydrology modules only. Event file C:\Program Files (x86)\ISIS\data\singleChannel.ief not found 6[/b] I checked and the event file is where it should be. How can that be fixed? Thanks. David

Exact soliton solution

Posted 13/11/2013 12:46 by eshurgalina1

No replies yet

Hello, can you help me, please, I need to find a full expression os solitary wave. I know that it has to contain (sech^2(...)+sech^4(...)+...)

Tabular CSV - can't generate panel velocities

Posted 29/04/2013 09:05 by MattHorritt

No replies yet

Hi all Having problems trying to get Tabular CSV to output panel velocities - am using "Tabular style output" and "Estimated panel velocities" options - but still only produces single value for each section. What's going wrong? For current model can do it by hand as I only need 1 section - but a but tedious in other cases. Cheers Matt

Flood volumes

Posted 06/12/2012 08:25 by Phil

No replies yet

Hi everyone, I have just built my first ever model and it runs OK, but now I need to know how to get ISIS to tell me flood volumes at particular points along the model. Is anyone able to tell me how to do this? Thanks, Phil

How to perform 2-D modeling??

Posted 04/10/2012 03:50 by yili

No replies yet

Hi, I need some help in performing simple 2-D modeling. The ISIS Guides have not explained the issue clearly. In my case, basic geometric properties of a small river are available, which should be sufficient enough for building a model. However, no GIS information is available, such as DEM. In this case, can I proceed without using GIS information? Based on the ISIS 2D Quick Start Guide, it seems that ISIS requires to apply ISIS Mapper in building a 2-D modeling. Do we have to use GIS information? Do we have any simpler but more straightforward option to delineate a small river? Can we just build a model by "drawing" a river step-by-step, as we can do in HEC-RAS? Regards Yi

model stop working after global change

Posted 17/05/2012 09:39 by Lei Yang

Last post 17/05/2012 10:09

3 replies

Hello All, I have a 1D ISIS model working well. Just made a global change on manning n for river sections and bridges. The model is failure to execute. The error message is " unidentified unit with type = 0 data error at line 1677 stopped in chsod" Could anyone tell that how can i remove the bug after global change? or do i have to change the manning n one by one river cross-sections? thanks in advance. Lei

Conduit Top Slot

Posted 01/05/2012 10:07 by Francesca

No replies yet

What are the default values that ISIS uses when applying a global top slot from the .ief file? Does it follow the standing advice that "typically, dh would be zero for a rectangular culvert, and 0.04*radius for circular/arch conduits & a typical slot height would be half the barrel height". Also - is it possible to find out the area of the slot which has been added to any particular culvert? Thanks

Double precision?

Posted 20/12/2011 12:27 by colin_riggs

No replies yet

Hi all, I am developing a linked ISIS-TUFLOW model in which the TUFLOW domain receives an inflow from direct rainfall. I have therefore opted to use the double precision version of TUFLOW. However, when I also use the double precision version of ISIS I get an error informing me that the ReFH boundary unit is not compatible with the double precision version. The model will run using double precision TUFLOW and single precision ISIS but I am concerned that this may result in mass balance errors across the HX boundaries. Is this likely, or is the combination of single and double precision models acceptable? Also, is the ReFH method likely to be incorporated into future double precision releases of ISIS? Thanks.

Working model now broken after moving file

Posted 18/11/2011 20:37 by dgds40

No replies yet

Hi. I've just started using ISIS at uni and I'm having some issues. I made a model for a 1 in 2 year flood event that worked fine and so I went on to make one for a 1 in 10 year event as well. I created a copy of the file in a new folder to edit that rather than start again but now it doesn't seem to work, even though I haven't changed anything. Any ideas why this might be happening? Thanks EDIT: Sorted. One of my coursemates had the same problem and it turned out it was an issue caused by not importing the initial data when moving the file to the new location.

iflag -2 error

Posted 31/10/2011 10:05 by k_haseldine

Last post 18/10/2012 13:03

6 replies

I have been developing an ISIS only model over the last few weeks and keep getting an E1196 iflag -2 message. The help file suggests this is due to the channel running dry, but the error occurs following only a very minor change to the model. If the geometry is copied into another ISIS window and re-saved, the error often disappears. I have also tried to re-run the model using ISIS v3.4 with no changes at all; the model works fine in this version. Has anyone experienced similar? Thanks

Floodplain representation

Posted 09/08/2011 13:56 by fou

No replies yet

Hello everyone. I'm a student and new to ISIS and I am having some issues with my model. I was wondering if anyone could help. I am trying to represent a floodplain section using spills and reservoirs. I made a fairly simple reach to avoid as much problems possible. However the unsteady results I get seem to be unreasonable as the outflow is much higher than the inflow for no apparent reason. Could it be some wrong connections or data I put in the spills and reservoirs? Is it better to use the floodplain section and connect it with the reservoirs instead? Any help would be reaaly appreciated. Thank you.


Posted 05/05/2011 14:09 by Dangerous_Brian

Last post 06/05/2011 11:53

1 reply

I'm trying to generate hydrographs from FEH and ReFH models. After entering the necessary details and clicking the tab 'Calculated Hydrograph'/'Results' I receive the error message: Fatal ISIS Flow Error View diagnostics file ()? I have tried setting the calculation report to 'Published report' but to no success. I'm using ISIS Does anybody know how to overcome this problem? Cheers Dominic

Time step?

Posted 15/01/2011 07:47 by vantri23

No replies yet

Hi, I am wondering when should we use the Unsteaduy (Fixed Timestep) and Unsteady (Adaptive Timestep)? The fact when I was running a large river network with the Unsteaduy (Fixed Timestep) with the timestep of 1800s, the simulation was ended after about 45 minutes. However, when the model was run with the second choice, it took at about a day (24 hours) to finish a run. In fact, I set the minimum timestep of 90s and during the simulation, sometime the time step dropped to 112s. What should we do? Should we use the first or the second alternative? How about the accuracy of the model? As I observed, the second give better results. Any ideas on this are very much appreciated. Best regards, Tri Van

Summary of the model?

Posted 04/12/2010 07:29 by vantri23

Last post 13/12/2010 08:22

5 replies

Hi, Can anyone help to make a summary of the ISIS model? The summary should have number and type of boundary conditions, cross-section, and so on. I am looking forward to having your help. Best regards, Tri Van


Posted 25/11/2010 08:44 by Konrad

Last post 25/11/2010 12:04

1 reply

Following the recent post on using a rating boundary condition, I thought I'd post some clarification on the various rating units used in ISIS; all three use a Q-H relationship, but are applied in different places/ways: QHBDY is the unit to use as a downstream boundary condition. It has one node label - conincident with the downstream node of the model. QH CONTROL is effectively a weir or other structure with a user-defined Q-H relationship, and would sit somewhere in the middle of a model. It has two node labels, coincident with the nodes attached upstream and downstream to it. QRATING is used in routing models to obtain an output water level (not calculated directly by routing methods) for the current flow. It is particularly important if a routing reach is linked to a hydrodynamic reach upstream of it. The QRATING unit sits directly on top of a routing node (i.e. has the same node name and no effect on connectivity). Regards, Konrad

Error message

Posted 23/11/2010 06:19 by vantri23

Last post 23/11/2010 08:36

2 replies

Hi, Can anyone explain what the following error message mean? and how to solve it? *** Error above line 6258: different values (+/- 20 %) for Mannings n encountered within one panel *** Best regards, Tri Van

Automatically adjust hydraulic roughness coefficient

Posted 11/07/2010 10:28 by vantri23

No replies yet

Dear All, I would like to make a code in Matlab, from which the Manning's n coefficient of a cross-section of a channel will be changed from 0.02 to 0.09 with the step of 0.005. It means that there should be about 14 runs for a cross-section. Many thanks in advance for your great help. Best regards, Tri Van

How to call different hydrographs

Posted 06/07/2010 10:00 by vantri23

Last post 07/07/2010 09:58

4 replies

Hi to all, I would like to use Matlab to automatically call different hydrographs as the upstream boundary conditions of an ISIS model and then run the model. Could any body help? Many thanks in advance. Best regards, Tri Van

Surcharged culverts - instability

Posted 29/06/2010 13:38 by dominickearney

Last post 29/06/2010 16:04

3 replies

Hi I've inherited a model which consists largely of culverted water courses. The culverst are surcharged for most for the run and the model is extremely unstable throughout. Does anyone have any hints on modelling surcharged culverts stably? Thanks Dominic

polutant transport in ISIS

Posted 23/06/2010 10:35 by vantri23

No replies yet

Hi all, I am applying ISIS to model the polutant transport along a coastal river reach. I would be very grateful if any of you could send me any tutorial/guidelines/application of the ISIS model for the purpose. Many thanks in advance. Best regards, Tri Van

Start time must be less than end time

Posted 22/06/2010 03:13 by vantri23

Last post 23/06/2010 02:13

2 replies

Hi to all, I have just made a single river network with one junction. When the long section is executed, an error message appears as follow: "Start time must be less than end time" - I wonder what wrong I have done. I have checked all the boundary conditions and everything seems to be normal. When I run the model with the Steady Flow condition. It is working properly. Then, the Unsteady Flow model was executed (after the Steady Flow model), it also run well. The question is why the model is not working stably? Many thanks in advance. Best regards, Tri Van

Error message E1023 & E1066

Posted 30/04/2010 19:06 by sohel

No replies yet

Hello I am getting error message E1066 and E1023.In the diagnostic file, it says "Calculated water level is higher than the channel boundary" for E1066 and for E1023 it says "ERROR in unit type US BPR Bridge". My model is complex one. can anyone help to way out of these errors. Thanks in advance sohel Today: 18:02

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