Subwatershed Delineation

11-15-2010 04:40 AM
New Contributor

I delineated subwatersheds and there are areas of land that were not delineated, I'm guessing due to the lack of drainage lines/drainage points in those areas. Is there anyway to create subwatershed polygons in the areas where no subwatersheds were created? I have a polygon outlining the watershed, along with the subwatersheds that were delineated. Is there a tool where I could these two layers to say "create a polygon where one wasn't created within the larger polygon"?

Thanks in advance.

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3 Replies
Occasional Contributor
Could you post a screenshot of what you are trying to do?
If you haven't already solved your problem, that is.
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New Contributor

I have the same question that Angel posted. I attached a screen shot of what I' trying to do. The red line is the watershed delineation and the gray polygons are subbasins created by the geohms project generation process. For some reason the area not shaded in gray was not included in the project area. This is throwing off my drainage area numbers. How can I include this area into the project area? This problem occurs in other areas (project delineation doesn't match with watershed delineation, but to a lesser degree.

If I have to start a new project, could I keep the project points and subbasin polygons created for this project (I'm new the geohms)? Similarly, If the discrepancy is caused by my using a different stream def threshold for the hms project than what was used for my original watershed delineation, could I indicate a, say, lower stream def threshold for a new hms project and keep the subbasin and project point data that I created on the old hms project? I hope I'm being clear.   

Any help here would be greatly appreciated.
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New Contributor
Did you ever find a solution to this? I'm having a similar issue. Thanks!
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