That's kinda what I'm thinking. Any recommendations in particular?

Screening seems to do well and to be easy to clean.

Regular nylon screening? Do I put that in my skimmer filter?

Do you set that up outside the main pond? Like, for instance, would I
put them in my waterfall box?
Our hyacinth are in berm ponds that act as veggie filters. The rule
of thumb, as I understand it, is 10% of the surface of the main pond
in the veggie filter. More is always better. Regardless of how much
space you have available, more plants is good. You can see our setup
on our website (see our profile)

A berm pond is a nice idea. Don't know if I can do that, but I can
float water hyacinth in the main pond. I have quite a few in there
now. It's not doing much to clear up the murkiness though. :-(

UV is a great interim measure. We prefer not to have it necessary in
the longer run. Algae cannot compete with more complex plants once the
latter get going! UV lets you crunch an algae bloom.

Sounds good.

What do you all think about the bottom drain issue? Can I get by
without one if I vacuum or scoop the bottom with a net on a long
handle or both?

If your pond has a low point, it is a great place to pull water from
for the filter.

Do I use one of those retrofit drains that pulls water from on top of
the liner? Do I need a submersible pump for that? Can I use my
skimmer pump? Do people sometimes need more than one pump in their
pond?

If the junk can settle in a veggie filter of regular
filter before the pump, pulling from the bottom is a self-cleaning
mechanism. We pull the water from the bottom of a 7' 'deep well' (old
septic tank) in the pond. The koi stir the muck, which drifts down
into the hole. The pump intake is 4" off the bottom in a 5 gal bucket
with as many 1/2" holes as I could put in it. Big stuff can't get in
and the draw on each hole is very low. Works great. Small stuff goes
to the veggie filters and settles.

Good luck.

Jim

Thanks Jim. That sounds like a nice design. What kind of maintenance
does that system require?

Joan