Relative Water surface elevation RWSE RSE WSE

[PaulHuffman]

Everyone seems to be talking about relative water surface elevation lately,  but I can't seem to come up with the correct search terms to find out more on how it is done.  I get the basic idea that you subtract a grid of elevations of stream course from the overlying land surface elevation and you get a grid that should show you where the stream might be able to break through to create a new stream path.  But how to you extrapolate the elevation of a stream out under the stream banks appropriately?  Is the same elevation from the stream always appropriate all along a line perpendicular to the stream?  And what do you do in stream meanders where the perpendiculars intersect?

Is the subject that I want to search for HAWS, for Height above Water Surface?

[PaulHuffman]

I found a link to the Great Basin Landscape Ecology Lab that has a link to Riparian Topology Toolbox which is a link back to the old ESRI ArcScripts web page.  But a search of this current Geonet thing doesn't find its way back to the old Arc Scripts and there hasn't been a good replacement yet.

The toolbox was designed to run in Desktop 9.1 to 9.3.  So far I haven't been able to get useful results by running this in Desktop 10.2.2

[PaulHuffman]

The author of the tools, Thomas Dilts, had some good suggestions for me.

I created a new map project with just the pertinent rasters in it. Set the units in the kernel densities to square map units. Clipped the bare earth raster and the stream raster to a small area of interest and sent to the output to a new file geodatabase on the C: drive rather than the SCSI external RAID where the whole rasters were stored.  Then ran the 10.1 model, and I got good looking results in 29 minutes.  Good looking except I have some -74 results in the output grid.

So I changed too many things at the same time to be able to narrow down the cause of the earlier failures.

[GerryGabrisch]

Paul,

Here is a link to a number of tool to create relative surface models.  There are tools to detrend by transects, Euclian planes, Voronoi polygons...

I would give detrend by transect a try first. 

White if you have troubles or questions.

ftp://lnnr.lummi-nsn.gov/GIS_Scripts/DetrendingTools.zip

[PaulHuffman]

Where did you get these? 

[GerryGabrisch]

I wrote them.

[GerryGabrisch]

Oh, and about the elevation under stream bank problem.  Unless you know where these areas are and surveyed them and created a new surface model based on these data you are out-of-luck and stuck with the original surface model.