Derek,
I don't know how big your pond is so that would change everything. Large ponds require automated equipment, large suction barges etc to dredge or remove debris from the bottom.
I have a tiny pond and I have had lots of great ideas but I haven't put many of them to the test as I don't have the time or the equipment.
1. I imagine a trashpump with a weighted suction end could vacuum the bottom. The outflow would have to go into a 'dewatering bag' or something where water would return to pond and debris stay out, or pump into a nearby woods or something.
2. A bigger pond could easily use the prop wash of a motor boat or a jetski to at least agitate and swirl up the debris till the bottom was clear. This way at least the stuff is somewhat suspended, aerated and then you could use aeration to help break it down. Breaking down debris and organic matter is nearly impossible if you can't get under it and stir it all up. Aeration and agitation will really speed up the process.
3. In my smaller round pond I wanted to try to use a stationary jet ski or large pump to get a 'whirlpool' effect going. This would at least swirl the leaves from the shallow into one pile in the middle of the pond. That would save a lot of handraking which is what I do now.
I figure I hand rake a couple hundred pounds of leaves, sticks and old algae from the 4-5 feet of shallows that I can reach. It leaves a nice sandy area and I feel like I'm making a little dent in the nutrient load.
But I agree with SetterGuy and others that for how many leaves actually came down in the fall till now, it seems like I must have crayfish or other critters helping break down the total burden of leaves and I do aerate from about June 1 to Sept when the heat breaks.
