Is that Lake Pend Oreielle? The USGS says they have a bathymetric map of it. Didn't dig too deep, as I usually don't open much stuff on my super duper computer, but on my tablet. (In case anyone sends me a nasty viri). But that might help. Then again, I'm sure you covered that base already. I do think LIDAR is used underwater. Maybe U of I has some knowledge, or Wazzou. If not, don your Reference Librarian scuba gear, grab the waterproof paper and pencils, headlamp, dingy, and head on out. You might get a new 'brare badge for that one. Then again, might take awhile too...hmm...

Even though I don't write letters anymore, since my Mom and Grandma are gone, and they were the ones who enjoyed them, it IS still a classic way to correspond. I have a friend and he and his partner send each other a hand written one every day. Kind of cool. Though I would not have the time, I think, to do that. Maybe if I get a special pen...
Well, I've rambled on here long enough for both of us. Have a peachy night 'bK.
Sincerely, Flat Pan Charlie