We live by a canal, our garden backs onto one much like yours although our gardens are all allotment style divvied up rather than straight off the back of our house.
No vermin down by the canal, no stagnant water or stuff coming off the canal. Sometimes a boat crashes into the side and knocks the odd pot over. We get a few midges in the summer but you just have to avoid them.
Ducks do bury eggs under the soil, which stink if you stick a fork into them.
Apart from that - it's marvellous. Always wanted to live next to a canal. Love it. Only problem is that gardening can be a spectator sport sometimes with all the people on the other bank staring. Yes I am digging out dandelions, get over it!