Posted Sat, 06 May 2017 18:56:09 GMT by Humayoon Rehman student
i have been working on dambreak simulation but continuous errors are arising in defining Broad crested weir.
The errors are:

Error No 340 : The weir in River JHELUM at chainage 2000.000 meter
                is located in a river reach without a cross
                section on both sides of the weir.
despite of the fact that i have defined cross sections on both sides of weir.

  Error No 86  : Error in the structure in JHELUM : 2000.000 meter.
                The water level in the weir in Q/h relations is not
                monotonically increasing.

is this error about reservoir storage or Q/h calculation for the weir?

Posted Tue, 09 May 2017 07:11:36 GMT by Mathieu Hellegouarch

Ref. error 340: it is correct that each structure in MIKE 11 must have one cross section located upstream, and another one downstream. If you have added such cross sections but you still get this error, it means that MIKE 11 is not able to "see" them, and I think that the most obvious reasons may be:
1. that you mispelled the branch name of the cross sections (i.e. that cross sections are defined on a branch with a slightly different name than the branch on which the structure is defined)
2. that you mispelled the Topo ID of the cross section: just like for the branch name, the Topo ID of the cross sections must be identical to the Topo ID of the branch on which you have defined the structure.

Ref. error 86: in this structure, you have a table with Q/h relationships, and something's apparently wrong in that table. Values must be increasing downwards. Sometimes this simply highlights that you didn't compute at all the Q/h relations (i.e. the table is still empty): in this case, simply recompute the relations. If you manually edited the table, you should either recompute again the relations using the dedicated button, or correct manually the problem.

Please let everyone know if this was usefull, or if you found other information useful for others :)

Best regards,
Posted Wed, 10 May 2017 13:46:12 GMT by Humayoon Rehman student
Thanks, i found it useful.

Another reason for error later found was that i had defined my dambreak structure as " Side structure + Reservoir " with volume vs elevation data for the reservoir but later i changed the Dambreak structure type to  "Regular" same was done for the Weir.
when simulations were carried out it was successful.  :)

But there the was no data for the dam in the model as i had no idea how to add reservoir to the model.

please guide me in this matter.

Humayun Malik
Posted Thu, 11 May 2017 16:23:17 GMT by Mathieu Hellegouarch

In short, you have two main options to describe a reservoir:
- the simple one, where the reservoir's storage capacity is described with a Level-Area or Level-Volume relationship. You can enter this type of relationship e.g. when you use the "side structure + reservoir" type. We may need to get survey data in the reservoir to assess this kind of relationship.
- the more detailed one, where the reservoir is described with a river branch and with cross sections along the branch. This is the same as the description you use for any other part of a river, except that here the cross sections have to describe the geometry of the reservoir. With this solution, the dynamics of the flow along the reservoir (i.e. between cross sections) can be modelled.

Hope this helps.

Best regards,

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