I have successfully been using the trace upstream in ArcGIS with 10,000+ points as flags to find what polygons are upstream (using a select of the polygons than intersect the upstream trace).
Now I need to know how far upstream a polygon is. That is, I know which polygons are upstream but I do not know the distance from the flag along the network to the polygon. If I cannot get distances even sequence would do (this is the first poly upstream, this is the second and so on) although distance upstream is preferred.
ArcGIS Geometric solution. I have close to 100,0000 flags (points) in total. Trace upstream works great but now I need to add the distance upstream to each feature.