Detrending is a process that removes the overall valley slope of the stream channel from the DEM. The edge of water points are used to approximate the valley slope and create a “detrending surface” and used to change the DEM from an ‘inclined’ position to a ‘level’ position. During this process, the channel topography remains intact and can be used to model the effects of changing the stage-height of the stream.
Detrend a DEM to Remove the Valley Slopein the Workflow Manager.
- Make sure the correct Survey Geodatabase is open.
- Make sure
Detrending Methodparameter is set to Water Elevation Points
- Click OK to run the tool.
Detrended DEMwill be added to the map.
- Briefly review the
Detrended DEM. In general, pools (channel features with low relief) should be blue, and banks should be green.
For advanced situations, you can opt to use a different surface to detrend your DEM. For example, a dry or partially-dry site could use a surface generated from the bankfull elevations. Please consult a CHaMP Analyst before using this option.
- Make sure other ArcGIS programs are closed (i.e. ArcCatalog).
- Use the Clear Workspace Tool to remove extra processing data that might be causing the error.
- Manually delete the
Detrendedraster dataset in the Survey Geodatabase, if it exists.
- Close and Restart ArcMap.