Ok, I would have thought that the pressure of a 5 acre pond pushing down on a pipe at 3 feet depth would have kept the water between the end of the pipe in the water and the surface from being pushed out. I guess not!

Any suggestions on what to cap the pond end with in order to remove quickly?

I have a forklift and 275 gallon tank that I have been using to fill the pipes at the T. Thanks for the help, much appreciated.