Ruh Roh!

A pond being built in a dry summer has cost me $20K and counting in repairs. There is no way to compact clay that is either too dry or too wet. We had to drain the pond and then had 6 feet of new clay added to the face of the dam in 6" lifts. Our clay was so dry when the thing was built that AFTER adding 6 extra feet, the weight of the earthmovers had compacted the dam's height 5 feet below our starting point (the top of the original dam was never disturbed). Contact your local NRCS agent and ask him to come check the integrity of your dam and to recommend what needs repaired AND who they think would be best to do the repairs. This service is free so make use of it.

I'm fairly sure the water is running along the bottom of the pipe. You can try to get the original builder to repair it. If he values his reputation (assuming it was good) he will repair it at his expense. RARELY will you get any builder to guarantee a lek free pond, but this sort of thing can be bad for his business.