My stream that flowes into my pond has a narrow point 20 ydrs before it enters the pond, if I build a wooden dam at this spot to slow the water down will this deposit the sediment behind the wooden dam and not in my pond.

Why does my water clear so quickly, I am using a net to remove leaves that are on the bottom and when I stur up the black muck mud I can see bottom again 5 minutes later, and the smell is like rotten eggs.

Thanks