I'm getting ready to design/price a renovation to some ponds in our city park. The only pond had limestone rip rap on the edges but it has slid into the pond or been covered with mud. These ponds are dirt bottom with no liner of any kind. We are wanting to dress up the edges and rebuild the waterfalls. Everything that was used about 20-25 years ago to build these waterfalls ets... was Limestone but now the limestone is flaking off or breaking. I'm looking for a clean neat large rock or any other structure for the edges of the pond. Any suggestions would be appriciated. I want to have a ledge that my mowers can mow right up to the edge of the pond with as little trimming as possible. I had thought about large concrete blocks 6' long by 3' high 3' deep with a 3 or 4" stone cap. I didn't know how these blocks would hold up to freeze/thaw. Has anyone done something like this?