Depends. Refing [[Stroudwater Navigation]] was a pain in the neck even though I had the main source in front of me the whole time.
[[Canal#Features]] would be much more of a pain. The problem is that it jumps between levels of complexity so some you would be looking at citeing from a school textbook and others from wighter tomes.
The effort required is such that if I was required to do it that article would still look like this
http://en.wikipedia.org/w/index.php?title=Canal&oldid=132489555
Which isn't really B class despite the claims on the talk page (I would argue the current version is just about).
You don't have to specify exactly which source each statement comes from (although it is preferred where possible). Just listing the references at the end of the article would be acceptable.