SDR：the study area contains basins

[jdouglass]

Thanks for the clarification here @lingyun, and I’m sorry for the delay here. The model uses the threshold flow accumulation value to determine what it considers a stream, so since this large, flat area is one of the lowest-elevations parts of the DEM, the model determines it to be a stream. This is compounded by the multiple-flow-direction routing algorithm, which can result in large, flat areas like this all being determined to be a stream.

As far as workarounds go, this comment from @swolny over in Riparian buffer values issues because of NDR output streams wider than in reality - #2 by swolny might be helpful. The post is about NDR, but SDR uses the same routing algorithm, so the approach should still work well.

@swolny

While we continue to work this out, you could try burning narrow streams into your DEM, which might cause NDR to create the narrow streams in its output. One quick and dirty way is to use the InVEST tool RouteDEM to create streams using the D8 algorithm, burn the D8 streams into your DEM, then use that burned DEM as input to NDR. I’ve had this help some times, but not others, since stream burning is generally messy and non-trivial to do well. Then you’d need to create your riparian buffers around the burned stream layer, and add them to the land use map.