Several years ago I siphoned a "swamp" (pond taken over by lily pads and cat tails) using 100 feet of 4-inch corrugated pipe.
It took a little bit of doing to plug the outlet end so I could fill the corrugated pipe with water. I don't exactly remember the size of PVC pipe I used to make a plug -- I guess it was 4-inch. Anyway, I used about two feet of PVC pipe, with a glued on pipe cap. I shoved it up the corrugated pipe. It was kind of loose. I slit the corrugated pipe and put two large hose clamps over it, to tighten the corrugated pipe around the the "plug."
I then used an electric submersible pump to fill the 100-foot section of corrugated pipe with water. The plug leaked some, but not so bad that that it wouldn't fill up the pipe. When I loosened the hose clamps on the plug, the plug blew out and it started siphoning. It took over two weeks to get most of the water out of about a 1/4 acre pond -- but it worked.
