Canyon creek those are good points you bring up. In my case the pond bottom is below the water table so I don't need to worry about causing a leak. The area where I will be testing ranges 6 or 7 feet deep and the bottom is very soft once you get down about 4 inches under the current pond bottom. My plan is to drag a heavy anchor along the bottom. I can drop the anchor from my boat and then pull it from shore with a long rope and my tractor. Then take the anchor back out there in the boat and drop it again. Essentially I'm going to plow the pond bottom in a test area to see what happens. It may be possible to drag the anchor from a boat also. You wouldn't dare do this to a compacted pond bottom.
Your idea of using the prop wash to disturb the bottom is interesting. Think of public boat launches, even in muck bottom lakes the launches are usually muck free from the disturbance. How much of the clearing is bacterial and how much is simply mechanical is the question. Windy, wavy shores don't have muck build up but secluded bays do, same question. But what we know for sure is that the waves coming ashore have a much higher concentration of dissolved oxygen than the bays do.
