The Douglas next to Loch Lomond is one of my local rivers so was down there last night to find the hydo people are putting in some sort of piping not sure if this will affect the river although about 150 to 200 meters after the get in they have put concreat blocks that have diverted the river so the river all flows river right it was easily runnable but worth a look before you paddle the river.

Hope this helps happy paddling :-)