Complex sentence: The Fence and Pipe flow device needs very little maintenance and limits where and how high the beavers can dam; however, to be most effective, the intake end of the pipe should usually sit in at least 3 feet of water.
Split into simpler sentences: The Fence and Pipe flow device needs very little maintenance, and limits where and how high the beavers can dam. However, to be most effective the intake end of the pipe should usually be sitting in at least 3 feet of water.