Can someone tell me from where I can get the data necessary to construct a reach network for Sebou river basin? The information I require is as follows:
Reach identifier - numerical value that uniquely identifies each reach segment in the stream network
From node number - an integer number that identifies the upstream node of each reach segment
To node number - an integer number that identifies the downstream node of each reach segment
Hydro-sequence number - a number that is used to sort the network in downstream (or upstream) order
Diversion fraction - a number in the range [0,1] that represents the fraction of flow leaving the upstream (from) node and flows to the given reach. For a network with no diversions, the diversion fraction is always 1. If a diversion is present, the sum of the diversion fractions among all reaches flowing from the same from node must equal 1.
If transport 0/1 variable - takes the value 1 if flow is transported through the reach and delivered to the downstream (to) node. Usually takes a value of 1 unless you want the stop flow through the network at a particular reach.
time of travel through the segment - can be determined from the reciprocal of stream velocity (velocity can be estimated using the Jobson equation - version of equation depends on whether or not you know the slope of the channel segment)
segment length
incremental catchment area for the segment (the area of the land surface having its runoff enter the stream network at the given reach segment)
total catchment area upstream - the sum of upstream area upstream of the segments downstream node - apportioned at diversions according to the diversion fraction
flow - the flow in the segment
Best,
Simon Sakhel
This thread might be related. Databases should exist, e.g. GRCD.
https://www.researchgate.net/post/Can_anyone_tell_me_of_a_free_portal_to_download_river_discharge_data
Another idea for getting a graph would be to click on a map with a mouse and collect points lying on rivers. Later you can create a graph out of it, assuming that points close enough are on the same river segment.
You could also navigate in OpenStreetMap to the interesting places and export the data in XML format (.osm). Rivers should be annotated with "waterway".
Regards,
Joachim