Zach,

To add a little more...

Another option is to drain the pond, then push the muck into an "island" in the middle of the pond and raise your dam so that the island will be well under water when pond is full. That was my approach recently when renovating an old pond. The "island" will be 3-4 feet under water and surrounded by 6-10 feet deep water. This was a "cheap" solution to the problem....in fact I did it myself with a small dozer. The end result will be not only a cheap solution, but some great structure also.