Hey guys thanks for all of the advice. A neighbor and I went out in a boat on the pond and looked down the vertical pipe. The collar around the vertical pipe is leaking in three spots. Small little pin leaks. The collar is inserted over the flange of the original pipe.

I don't know what to do, but would like to at least attempt a patch, maybe a header with a pvc pipe extending up from the original vertical pipe. This pvc pipe would rest right on the flange and hopefully raise the depth of the pond a little??? Seal the edge of the bottom of the pvc pipe on the outside and inside at the bottom. The seal would bond the flange to the pvc??? Please help.