Tuesday, February 24, 2009

Wide Flat Cross Section Bottoms

Written by Chris Goodell, P.E., D. WRE | WEST Consultants
Copyright © RASModel.com. 2009. All rights reserved.

A common problem with the import of cross sections from GIS that were developed with a terrain model generated from LIDAR is the cross section with a flat bottom. This is a result of LIDAR's inability to penetrate the water surface. As a result, you get a flat bottom that represents the water surface elevation in the channel at the time the LIDAR was taken.

This will cause problems right from the beginning of your simulation, particularly if you are running low flows (low depths), and your model will most likely crash right away. You can see the result of the lack of bathymetric data in the profile plot.
To fix this, you'll need to get some definition to the bottom of your cross section(s), either by approximating the channel bottom, or by field surveys.

1 comment:

  1. It is true!! I did the same when I face this problem. It took me several months to figure it out!! I should know this blog before..thanks for sharing !!!

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