HEC GeoHMS Terrain Processing - NHD Flowline vs USGS Elevation Data Quality

Discussion created by mbbrady on Nov 6, 2010

I'm trying to decide if I should apply the burn-in process as part of terrain preprocessing per the HEC GeoHMS user manual. I've read that when deciding to apply the burning-in process implies that flowline data are more reiliable than the DEM data.

So my question is, how should I go about determining if my NHD flowline data are 'better' than my USGS elevation data? What would be some key determining factors here?

A second and related question would be: what is an acceptable discrepancy between streams found using elevation data (w/ and w/out burning-in the flowline data) and actual locations?

Thanks in advance for any thoughts on this!