The road bridge in Cappoquin
The redoubtable F E Prothero, Rear-Commodore of the Cruising Club, wrote just over three pages about the Blackwater, from Kanturk down to the sea, in A New Oarsman’s Guide to the Rivers and Canals of Great Britain and Ireland edited by F E Prothero and W A Clark and published by George Philip and Son, London, in 1896, as a Cruising Club Manual.
Here is a PDF of the relevant pages. I have also put a link to the PDF on my page about the Blackwater, Bride and Lismore Canal.
Irish waterways history 