Ordering points along rivers in ArcGIS

Question

I have data on the location of water treatment facilities in the EU (green in the map) and of stations that control for water quality in rivers (blue in the map). I'd like to get a list of treatment facilities and water quality stations that are upstream and downstream for each treatment facility. Optimally the output would look something like the table below. Alternatively, listing all downstream stations (monitoring and treatment) for each monitoring station, would also be enough. The data on the stations and a river dataset is here.

It is of course possible to spatially join the stations and rivers. But this does not provide information of the order of stations along the river.

Using the elevation of stations in basin areas to get the order of stations also seems not to be a solution as different tributary rivers feed into larger streams.

Treatment fac	Upstr treatment fac	Downstr treatment fac	Upstr stations	Downstr stations	River ID
FR011013100000	FR011049600000; FR010295000000	...?	AR01097000	AR01094000	AR13
FR011049600000		FR011013100000; ...		AR01097000; AR01094000	AR66
...

Answer 1

RivEX is an ArcGIS Pro toolbox with many tools for attributing the network and searching for sites along the network. One such tool is the Find Downstream sites which generates a table listing what is downstream of what along with distance and catchment metrics.

Taking the sample data shown below:

Would generate a table as shown below; in this example I have filtered for sites 7385 and 7398. I've highlighted for site 7398 the first 3 sites it encounters which matches what is seen in the map and we see they are 10, 20 and 30Km away. You could then import such a table into other software for further analysis.