I'm still looking around and have seen some interesting grated drain
covers (much like landscape catch basin grates) which would be a huge
improvement over what I have. I also noticed that some vortex tanks
can be buried, and it sounds like the right sized unit is 4' deep.
Pretty pricy, but it makes me think that there still may be a way to
use a settlement tank of some sort. I need to figure out "pond level"
in the location where I might be able to put a tank. Offhand, I don't
know if that would be ground level, below ground or above ground level
(which I doubt).

What do you do in the winter, though? Our frost layer is about 2'
down, so the top water would definitely freeze up if left to its own.

The barrels you're talking about, are they those plastic ones or
something else? Where do you find them?

Thanks,

Dave