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Calculating cumulative values upstream in a stream network

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08-17-2022 08:46 AM
OleksandrStefankiv
New Contributor

Hello, I am trying to find a better way to calculate cumulative values upstream in a stream network. I have two layers for this analysis, topologically correct stream network which is split into 200 m segments and snapped points of culvert locations. The attribute that I am cumulating upstream is the fish passage rating of each culvert, so the end product is a stream network layer with cumulative passage ratings for each 200 m segment.

Current workflow is a script that employs snapping culvert points to the flow accumulation raster of stream burned-in DEM, SearchCursor function that utilizes Watershed tool to search for all segments upstream of a culvert that intersect with that watershed's domain, and UpdateCursor function to update the upstream cumulative values. 

As you can imagine, with a large number of culvert points, this process is very computationally demanding and takes long time to complete. In addition, due to coarse resolution of the flow accumulation raster, culverts are sometimes snapped to the wrong stream segment with higher flow accumulation value at bifurcations.

I am wondering whether there is a better way to do this using network analysis. I have access to the latest version of ArcGIS Pro. Thank you!

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1 Reply
DuncanHornby
MVP Notable Contributor

You could use RivEX to solve this. You would need to convert your river network into a  polyline dataset. Encode into the network  your fish passage rating, this can be done using the add spatial join tool, then run the Accumulate network attribute tool. This approach assumes each segment has one intersecting culvert. If you have multiple culverts intersecting a single 200m segment then you could sum the rating for that segment before running the accumulation tool?

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