Need advice about ducks going downstream

[tatswell]

I have a stream that goes through my yard. The ducks will go downstream a couple hundred feet. I don't mind, my neighbors don't mind, and the ducks for the most part always come back around dark. However this has been somewhat problematic since having snowfall- Last night I had to trudge through the snow downstream after dark to find and bring them back- since they seem to not mind being in the frigid water all day! But it is concerning to me in these temperatures.
I'd like to put a fence over and in the stream to stop them from going downstream. Any ideas or pictures would be helpful.
This is where I have to put a fence in (there is snow on the ground now)

 

[Miss Lydia]

I have a stream that goes through my yard. The ducks will go downstream a couple hundred feet. I don't mind, my neighbors don't mind, and the ducks for the most part always come back around dark. However this has been somewhat problematic since having snowfall- Last night I had to trudge through the snow downstream after dark to find and bring them back- since they seem to not mind being in the frigid water all day! But it is concerning to me in these temperatures.
I'd like to put a fence over and in the stream to stop them from going downstream. Any ideas or pictures would be helpful.
This is where I have to put a fence in (there is snow on the ground now)

seems it would have to also come out of the water and onto the land on each side or they will just come out of the water and walk around maybe. I have seen people have done this around here to keep cattle out of the mountain river.