Unfortunately as you may have found out doing something for a long time doesn't mean you do it right or well.
Sure hope you get this fixed. Definitely a faux pas not putting in at least one collar. It doesn't give me much confidence in your contractor.
At least your pond holds water which is a good point. There are worse fixes. I know some folks up in southeast Indiana where the hollers leak like a sieve.
I have been doing some reading Cecil. The National Engineering Handbook on dams. I found it rather interesting that they don't recommend anti-seep collars any more except on the lowest risk dams. They prefer a filter diaphragm, which is really a packed bed of sand it seems. Here's a snippet.
628.4501 Anti-seep collars
For many years, anti-seep collars were the standard
design approach used to block the flow of water at the
interface of the conduit and the backfill surrounding
the conduit for all embankments designed by most
design agencies. Based on knowledge gained during
the period of intensive embankment construction by
NRCS and other agencies in the 1960s through 1980s,
the use of anti-seep collars was reconsidered. Beginning
in the mid-1980s, anti-seep collars were eliminated
in designs of major embankment projects because
they were judged to be ineffective in preventing many
types of failures observed. All of the major embankment
design agencies, such as the U.S. Army Corps
of Engineers (USACE), Bureau of Reclamation, and
NRCS, as well as private consultants, now specify filter
diaphragms rather than anti-seep collars. Filter diaphragms
have been recognized as superior to anti-seep
collars as a seepage control measure. The NRCS still
allows the use of anti-seep collars for seepage control
along conduits for low hazard dams that are built according
to criteria in Conservation Practice Standard
(CPS) 378.
Perhaps all our dams fall into the lowest risk category. Not saying that I think an anti-seep collar wouldn't have helped or shouldn't go in for Round 2. They just found they can fail. I found their comment about failures upon quick filling too close to home.
Several NRCS embankments constructed in
the 1960s and 1970s failed the first time the
reservoirs filled following construction. The
embankments that failed had anti-seep collars
that were properly designed and installed,
and the surrounding backfill was adequately
compacted
