Oh, puhleeeeezzzze!!!!

There is heavy industry running 24 hours a day; the kind of heavy industry that can be heard and felt miles away.
Freighters run the river almost constantly which could explain hearing the same noise up-river in a lake.
Heavy truck traffic noise will carry many miles.
Some people are more sensitive to the 60Hz hum from power lines.
There are several heavy rail yards in the area on both side of the river.
And let's not forget the gigantic freakin' salt mine directly under your feet.
I live ten miles from anyplace, and have the "power surge" interrupt my sleep. Once, yes, but six times or more?