Hello again Stacie,
Thank you for your continuing assistance. Your response does help me in thinking about how much effort to make in correcting the stream delineation. While quickflow might be a key component of what we will present in the final maps for our project, I would be more concerned about the influence the inappropriate stream placement might have on our other results, as you note.
I have been trying your recommendation to force a different stream network. However, all the tools seem to be (inappropriately?) filling certain valleys in the DEM, including the RouteDEM tool. This makes the valley floors pretty much flat, which in my mind is contributing to the stream mapping issues, especially since these flattened out areas correspond well to the regions where the stream map is placing streams everywhere. As a result, the bunching of streamflow in certain valley floors remained even with the D8 algorithm RouteDEM method.
To show what I mean with the DEMs, I am adding screenshots of the filled DEM produced by the RouteDEM tool, and below it a picture of the original DEM for comparison. The pop-ups show the huge difference in elevation between the two for a pixel in the valley floor. I have also added a satellite image of the same area for context. Perhaps this is what the fill tools generally do, so apologies if this is a standard result. RouteDEM, Arc’s Fill tool and the Wang and Liu QGIS tool all filled and flattened this valley in a similar way.
Is this expected behaviour from these tools? I know there are some other options you recommended I could explore, but I just wanted to share this update as the RouteDEM tool sounded like one of the more promising solutions. I tried the D8 method with Arc’s flow accumulation tool on the original unfilled DEM, but those results didn’t look good, and the RouteDEM certainly seems a more promising options aside from the issues with the valley floor areas.
Sorry for all the additional comments for you to work through.
Luke