ed,not sure with the original size but this is how i did my pond.started with about 3 1/2 acres then added sections totaling i guess about 5- 5 1/2 acres now.the way i did this was build a new section and cut the dam down so as original pond gets full water goes in new section(plug overflow pipe)then when water gets right you dig the middle of the dam out first then take sides out this way you dont get your water all muddy again.i've done this 3-4 times now and it works great.you can also make the old levee a ridge,i put about 4 feet of water on the old levee.i find this better than lowering the pond.