Lateral structure extends past last cross section

[SimR]

Hi,

I’m having some issues with a 1D-2D model with lateral structures following the 1D model banks.
One of my lateral structures produces an error that I haven’t been able to correct.

For the Lateral Structure at
JCDS 18647.01
there is an error with the model data.
If the LS extends past the last cross section in the reach,
Shorten the LS or adjust the User Specified Intersections.

The model was built using HEC-GeoRAS and the lateral structure downstream end was originally snapped on the end of the Xsection line. I’ve moved it a bit upstream of the last Xsection to try and correct this problem but the same error message persists. I also added a section downstream to see if it would fix the issue but it does not.

There are 3 other lateral structures in the model that have been built using the same procedure and none of them produce this error message so I’m not too sure what’s wrong with it.

[Lonnie A]

Check your 1D reach lengths and if you are connecting it to the end of the XS or at the bank. If you look at the HW/TW connection tables in the lateral editor it should help tip you off on what is happening. Sometimes how RAS computes where the 1D intersects the geospatial lateral is off and you have to realign the ends of the XS so that it’ll not compute an incorrect intersection point.

[miss_rinda]

Hai SimR,

I faced the same problems as you..can you teach me step by step how to fix the problem? I really hope that you can help me,thank you.

[SimR]

I’m not sure I remember how I exactly fixed the problem.

I believe it was a combination of a few things.

I think there is a possible issue with the way you draw the LS in HecGeoRAS. You must draw the line from upstream to downstream.

You also have to adjust the Weir stationing reference (see image)
For example: 2077.101+4.375=2081.476

Also see Lonnie’s answer of course.

If that doesn’t work send screenshots of your issue and I’ll see if it helps my memory!

[miss_rinda]

Hai SimR. Thank you for your help. But it seem nothing change and the error kept appear even I tried to solve it in many ways.

[miss_rinda]

Did this picture that cause the problem? I really didn’t understand how to fix it. The first picture show the error at cross section 26153 and the second picture shows the cross section of 30685

[Author]

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