NS7578 : Kelvinhead, Dullatur BogThe drainage ditch that connects to the Auchincloch Burn. The O.S. name this the 'Bonny Water'.
From 'Reports of John Smeaton' (Engineer, Great Canal) written in 1764, pub. in London 1812.
"A drain that passes lengthways through the (Dullatur) bog, has, for half a mile in the middle thereof, no sensible run at all; so that the same trench is the head of both of the Bonnie and the Kelvin."
This 'trench' was mapped by Timothy Pont in his manuscript of c.1590 (for these parts) and named 'Bonny R.' as far west as the present Craigmarloch bridge area. J. Blaue in his Atlas novus of Scotland, pub. Amsterdam 1654, joined both together and if his mapping was correct (if) a connecting ditch must have been dug in the intervening period.
Seeing two burns which flowed in opposite directions joined together do not make sense until you have written proof of the existence of such from a famous engineer.
It therefore clear that this trench/ditch was dug to provide drainage and long before the canal was dug. It was only with the construction of the banking carrying the tramroad from Kelvinhead Jetty to Banton ironstone works that the trench became separate.
Little mystery possibly solved.