Crawdads will use it and love it. I did almost the same thing in my pond. They seemed to wait to move in after sediments accumulated in the bottom of the pipes. Mine are not papershells but mine were in about a foot of water and there were always crawdads on them or around them. The only problem I found with mine is that the water moccasins loved the 3" pipe. They were close to my dock and I could watch the snakes going in and out of the larger pipes. Unfortuanetly part of my structure got damaged in the process of snake removal. During the act of removal a deputy happened to come to the house begging for votes. I cant imagine what he must have thought as he was driving up and saw me sitting on the dock shooting my pond with a twelve guage...I guess around here he has probably seen it all.