Yep...pond-s. My property is on a hillside with a creek flowing down the middle of it. Ive terraced the creek off to form 3 ponds. One pond spills into another and another. I also have a spring on the right side of my property... Thats where Im thinking about building this new pond. (I've mentioned it on here before) Its going to be a clear natural swimming pool. I've done some research, gotten a few books on the subject. Yeah, I know about the muck on the bottom over time. Im going to keep this vacumed in the summer months...just like a pool. But if I cant keep it clear....why waste the money on the rock. I'll dig it 15' deep and I wont be able to touch the bottom. Havnt done the "bucket test" yet.