I've heard that because duck poop is so much more liquid-y aka higher water content than chicken poop that it won't burn plants the way fresh chicken waste can.
Carol Deppe's amazing book
The Resilient Gardener she uses ducks as pest control in her garden and mentions this:
I don’t let ducks into areas of a garden that have low-growing greens in them that I plan to eat soon and raw.
I figure if you wouldn't want to eat it raw after ducks walked on it, then probably don't use duck water on it. So skip watering the bush beans with it, but it's probably okay to water the tomato roots?
Also, several years ago, my wonderful husband set up automatic drip irrigation for me in our raised garden beds. It's just using city water, but maybe after we have our farm we can do something else. With drip irrigation, only the base and roots of the plants get wet, so I've thought someday adapting it to use the nutrient-rich duck water. I do see a couple issues with this, though. The first issue is that my ducks make the water very, very muddy. Largely with actual mud but also with their constant pooping. So I'd wonder how well that would work going through the slender irrigation hoses - maybe make sure to get larger ones that won't clog?
The other potential problem I see is that I'm not quite sure how I feel about "duck poop water"-marinated carrots.
Probably fine, and I suppose that could be avoided by growing greens and root vegetables etc in a different area, but I practice chemical-free companion planting and also not growing all of any one thing together. Meaning in one 4x4' bed divided into sixteen squares, I'll plant 10-14 different kinds of fruits, vegetables, herbs, and flowers. That makes it a bit more complicated.
Maybe you could start on a smaller scale and experiment with irrigating from a large barrel instead of a pond at first? I've subscribed to this thread and I hope others will chime in and share their thoughts and experiences too.