Pond Boss Forums POND CONSTRUCTION Building a dam Back at it

Mike, unless the total structure, including the drain pipe was completely sealed....there was no bouyancy. If the outflow pipe was exposed to air (below the lowest water level), water pressure would push against your structure attempting to flow out and fill the air space.

Think of an empty cup in water...sealed, it floats. Add a tube at the bottom of that cup that exits the water below the water level and that cup will sink from it's own weight.

If the outflow pipe rose as a supply line that exited above the high water level, then yes, the structure would become bouyant.