[neeyole]

It was the same bounding polygon. I just did and the results and getting worse and worse. I can’t find any explanition about that:

1. Snapshoot from Ras mapper ( as you can see the wáter Surface is not even continuous and it happens along all my river)

2. Snapshoot from View 3D multiple cross section (any water is being displayed outside my levee!!)

PLease help I am starting to be desperate

[neeyole]

Hi Cameron,

Thanks a lot for your quick response. I do have leeves but I didn´t know that the leeves cut the bounding polygon like that because I have that part (see pic attached) as well where you can see the water is passing through the levee and there are some patches that´s why it was a bit confusing. What am I doing wrong?

[neeyole]

Hi guys,

After a lot of work I realized Cameron was right about the DEM. Simply, the way of the creation of the TIN was not the correct one. So any similarity with the reality was fiction. I’ve already managed to do it correctly by creating the TIN from the contour lines and points with the Z value extrapolate from the DEM instead of using the tool from raster to TIN that was causing so many problems. Only say thanks and I hope that this information can be useful for someone else in the future.

I would also like to ask if someone has an idea about the error I am making in this boundaring Polygon that is the result of importing the data from HEC-RAS to GEO-RAS. Why is it not consistent throughout my TIN?

Many thanks

Laura

[neeyole]

Hi Jadams,

Thanks a lot for your response. I think that the idea you suggested is quite unlikely since I used the GeoRas tool by which the cross sections are drawn automatically. I got some advice from an Hydrologist and he said it has to do with the accuracy of the DEM that even though it has a really good resolution (2m) maybe not enough to extract an small stream.
But anayway thanks a lot for your tips

[neeyole]

I got the 2 m resolution DEM from the Centre for Environmental Data Archival and also a 5 m resolution DEM from another agency and they matched. I just checked Google Earth as you suggested and seems to make sense. I created the Tin from the DEM, there may something wrong with that?

[neeyole]

My topographic data is based on a DEM with 2 m resolution and I was exporting the geometric data con GeoRas. Yeah they matched quite well and also the imagery has a really good resolution.

[neeyole]

Hi,

Just one more thing if you could. I am working on the bank lines now to make sure they are consisten and I was in doubt since accordingly Arcgis the bank point should be where the red spots are but It doesn’t make any sense. If I establish them relying on the 2-5 year flood height they will be out of the main channel. What should I do? any suggestion?

Many thanks

[neeyole]

Thanks a lot Cameron! I already redid it and it makes sense now! I just hope not to have more silly problems!
Thank you again I really appreciate your help

Laura

[neeyole]

Sorry for the obviousness of the question but when you say that you check the Banks elevations in profile view to make sure they are consisten, what do you mean by consisten?

[neeyole]

I was seeing that something was wrong with the profile but I just assumed that the direccion I was told was the right one? thanks for that Cameron. Just one more thing, regarding the bank channel should I stick to the points I get when I digitalize them according to the reality or modify them in HEC-Ras?
Many thanks for your help

[neeyole]

There you go the geometry I imported with Geo-Ras and the Project in HEC-RAS. I had to modify all the Banks but I am not sure if I did it right.

Many many thanks Cameron, if I can help with something let me know.
Nueva_carpeta.zip

[neeyole]

Hi Cameron,

Thanks a lot for your reply.

I run the program with a mixed flow regime since I got changes in the slopes. So I set a Normal Depth for upstream and dowmstrean of 0.01. I also run the program with a Critical Depth but it didn’t work either. Attached there is a snapshot of my cannel with a flow of 18.4 m3/s. But if I change the flow for the 50 year flow event (That is considerably bigger than the mean flow (594.4 m3/s) is almost the same.
Only to make sure, when you digitalize the river and Banks line as well as the flowpath in GeoRas is always from upstream to downstrem right?

Many thanks for your interest at least is nice to share it!

[neeyole]

Thanks Jadams for your response. I put manning’s values manually and the rest of the inputs seems to be ok. The strangest thing is that there is no much difference is I put a tiny flow or a huge one. The floodplain is completely full!.

Many thanks

[Author]

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