After the 2 year drought in kansas i seen over 50 ponds that were cleaned out that looked very similar to yours. around here they use a large track hoe and dig a hole on the water by the dam and have a large dozer push the muck to him and the track hoe sits on the dam and scoops out the much. They were charging 300 per hour for both pieces of equipemnt i would say aound 3000. I had a 1/2 acre pond done and it was $1300. they did a great job. good luck
