My pond will be 35x25 x4 ft at the deepest, and from the deepest section it is up 2 1/2 feet to the first planting ledge. Do people have ideas as to what I can do/build so the dogs can safely climb out the deep end? I'd like it to blend in with a natural pond. I was just going to pile up rocks but I'm afraid they will be too slippery for a firm foothold. Thanks.