On the road now, otherwise I would post some pics of our pond- Ducks, fish, turtles, snakes, bullfrogs, big bullfrogs, (about 20-30 adults in a half acre pond), ducks, turtles, more ducks, still more turtles....did I mention ducks?
Estimated half acre pond with island in center, home to approx. 75 flying Mallards, Khaki Campbell, English Callers, 3 semi tame Wood Ducks, 6 more wild Woodies that visit around feed time; 5 Toulouse Geese. An assortment of Snowy Egrets, and some cranes that I do not know the name of keep the sun perch population in check.
If anyone wants some ducks, I'm in southwest LA, near Lake Charles; free, but you catch'em. Would like to thin out population to about 10 Mallards, to many, they are bad for feeding along the waters edge until they undercut the bank. Some places they can swim under the grass ledge it is so eroded.
I do understand your concern; I to was worried, but after a friend of a friend laid his tractor over in his pond while cutting grass, (his ducks had weakened the edge of his pond I am told). I started spraying. My pond edge is so bad, whenever I do cut, I use the riding mower, and first walk the perimeter. I try to spray, then when the grass starts growing, cut it a couple of times before spraying again. I am tempted to try to construct an offset wiper, I understand there is virtually no drift with those.
Anyway sorry for the ramble, and good luck with your endeavor; Lots of good ideas are usually tossed around a post such as yours, one of the reasons I like to visit.