I have DTM for quite small area (400x200 meters) which was interpolated from elevation points. I want to create raster which will show water stream (not arrows but basically slope and river flow map - output from Flow Length would be enough). My DTM looks correct.
I use Fill to fill gaps and then Flow direction, where the problem occurs as you see below. For some reason there are created these straight lines which then also influence the Flow Length output. Please do someone know where is the problem and how to avoid it? Maybe the problem is that the DTM was created by interpolation, the area is to small or that there is small "lake" in the middle.