"Capt. Rob" wrote
100% wrong. The bottom conditions of the Sound are quite unique and
specific after thousands of years. It's nothing at all like the bottom
of a septic tank. Of course it helps if you actually know what "silt"
is. You clearly don't. Quite simply...

1 : loose sedimentary material with rock particles usually -uf,1-
millimeter or less in diameter.

That's exactly what you'll find in the bottom of a septic tank and must be
removed periodicallty. You clearly know nothing about septic tanks else
you'd know the bottom of the LIS isn't as unique as you'd like to believe.