Would my ducks fall off a cliff?

Now that I’m figuring out my plan for our garden, I am also considering how to fit ducks and a pair of geese into the plan. I want to have chickens for a composting system and eggs, and have had chickens before: But I’m new to ducks and want to own a few ducks for eggs and slug control and two geese for flock protection (and because they are my favourite animal). I would probably keep them confined in a rotating system, but am considering letting the ducks and geese have free access to most of the garden for slug control, and also so they have access to play in our creek.
Now what I am wondering is: at the edge of our property the creek ends into about a 7 m high drop waterfall (which is also the edge of our property). The creek isn’t very deep (half a meter at a few of the the deepest spots), but it can be fast flowing occasionally when there has been a lot of rain.
Now I have seen footage of ducks bumbling about in a creek, floating along with the current and foolishly floating straight into a drainage pipe. Now I’m worried if my future ducks would be foolish enough to fall of a cliff, floating along with the creek.
Legally speaking, I’m not allowed to put a fence across the creek, because of the risk of it obstructing the flow of the creek and creating an unintended dam. Now I’m still considering building a fence because I’m equally concerned about children playing in the garden and falling off the cliff, but it would have to be a kind of fence that has a kind of quick release so that if a blockage occurs I can deal with it easily, but sturdy enough that it can withstand the force of a small child falling into it.  Also the holes in the fencing should have to be big enough that it doesn’t function as an unintended fish trap (not that I have seen fish in the river, but I could get into trouble with the law for illegal fishing).

What do you think? Any advice or thoughts are welcome!

the ducks I grew up with, mallards, could fly if they really needed to...don't clip their wings and they'll be just fine

I don't have any advice because I've never taken care of ducks, but I just wanted to say that your land is beautiful! Good luck! :)

Orin Raichart wrote:the ducks I grew up with, mallards, could fly if they really needed to...don't clip their wings and they'll be just fine

I realise they probably wouldn’t get too hurt from falling off, but once they’re off the cliff it is quite impossible for them to get back up and they will most likely wander off (towards the road where they might get overrun by a car) I don’t want to lose my ducks, and I can’t keep an eye on them constantly to see if they went off and go to retrieve them.
So basically what I’m asking is, would they avoid to go off the cliff, or would they do so without hesitation, resulting in me having to go get them every time.

S. Bard wrote:

Orin Raichart wrote:the ducks I grew up with, mallards, could fly if they really needed to...don't clip their wings and they'll be just fine

.... but once they’re off the cliff it is quite impossible for them to get back up and they will most likely wander off (towards the road where they might get overrun by a car) I don’t want to lose my ducks, and I can’t keep an eye on them constantly to see if they went off and go to retrieve them.
So basically what I’m asking is, would they avoid to go off the cliff, or would they do so without hesitation, resulting in me having to go get them every time.

then getting ducks isn't such a great idea unless you feed them far away from the water fall.  our mallards staid inside and outside the fence (flying when they chose) but generally staid close to the pond fed by our artisan well....every now and again, they would go all the way down the ditch to the far end of our property and get into the roadside ditch.......since they knew we were the source of the grain and would call us out to feed them if we missed feeding time, they always came back.

as long as your neighbors aren't hungry and don't feed the ducks, your ducks will come back on their own. especially if you have good nesting material/locations for them. We fed our ducks grain/corn every day at a specific time; in this way the ducks knew where home was. As a kid I'd go outside and quackly loudly using their "call and response" quack (if you get mallards, you'll soon know what that is), before throwing out the grain...they'd come running and quacking back their response quack to my call quack  -I loved those ducks; what a happy creatures!

Ducks are rather dumb. I had one of mine (peeking duck) nearly walk over a mosquito torch I had next to where I was working. You will need some kind of deterrent to keep them away from the property line. Non-functional poultry netting is a good option and large enough not to be mistook for a fishing net. If you train the ducks to associate the orange poultry net with boundary, any orange resemblance can work, including orange rope.
The fiberglass stomp posts are ~$2.50 USD depending on where you are and can be easily pulled down and moved. The electric poultry netting in general is an amazing investment for rotating birds into beds and keeping pests out. Amazon has a few options ~$250 for a good set with solar box. Make sure you disconnect the bottom row or two so the grass doesn't short the circuit.

Welcome, Aaron!  Glad to have you and your duck expertise here on Permies.  

No duck comments, just saying hi.