I've got two polyline shapefiles; one showing the location of cross sections taken across a river and the other containing the river centre line that has been split by the cross section layer to create multiple features. Each cross section contains a unique ID along with some additional information in the attribute table (most of which isn't too important - mainly the ID). Each river centre line feature also contains a unique ID.
I'd like to spatially join the river centre line features to both the upstream and downstream cross section features - the result being that each centre line feature now contains information on the upstream and downstream cross section IDs, The output shapefile needs to contain a single feature for each river channel with the connected upstream and downstream section names in the attributes.
Using the detailed MS Paint example image below, channel 1 should show it is connected to A and B, channel 2 connected to B and C, channel 3 connected to C and D etc.
I have access to ArcMap 10.2.
I had previously attempted to use the spatial join tool as suggested by @mmoore, however this tool creates a duplicate of each river channel polyline in the output. Each feature then contains either the upstream or downstream section name. Is there a way to either produce the required output using the join tool, or maybe by dissolving the output somehow?