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I am trying to update a small portion of my 2D mesh to reflect grading improvement only on my site. All offsite grading is unchanged. Creating a combined DEM within GIS software shows no changes in elevations offsite. However, when resampling, elevations across the entire model in InfoWorks ICM, offsite elevations have varied (in areas where the terrain has not changed). If a feature were added that allowed only 2D Zone vertices within the terrain extents or designated boundary to be resampled, it would improve existing to proposed results comparisons by ensuring offsite elevations are unchanged.
Resampling across an entire terrain has created problems for urban 2D models, often we'll see changes in water surface elevations in areas thousands of feet away from areas of impact (that are clearly hydraulically disconnected). When we zoom into these localized areas we find it's because the terrain elevations are different, and that is only due to the resampling... A feature, like the one described above, is essential to demonstrate the design has satisfied criteria where local jurisdictions require no rise (0.00 ft) in water surface elevation.