For when we have to do it again? That's how things generally turn out for me.
Like ML says, be real careful. It's not too hard to make a mistake with heavy equipment. That stuff can kill you and never shed a tear.
What to do with the muck? Depends on what it is and how big the pond is. That stuff is not too friendly at removal time. A lot of it will probably be sand that washed in. If you mix it with all of the accumulated muck, it can be spread over existing acreage. If it is all sand, it is pretty useless and can be only used to fill low spots. No matter what it is, it will probably not be good for rasing the height of the dam. That takes good sandy loam.
If you have access to a dozer (he does), ML's idea of building an island works real well. But, you have to have a source of good clay to pack around the debris or it will, over time, flow back to the bottom.
How big is the pond?
