Pond survey camera suggestions?

ProfHankD wrote:

I have two half-acre ponds on my property, connected by overflow from one into the second, both fully lined. They're supposed to be about 12' deep, but the lower pond clearly is down about 4'. Basically, I think the liner has a tear and is leaking.

So, here's the question: how can I rig a camera to do a survey of the bottom looking for the leak? I've tried with a couple of waterproof 360-degree cameras I had around (Nikon KeyMission and iview 360 pro), but the video they record has exposure issues and I really don't see anything clearly unless it's within a couple of feet... although I'd say the water has about 3-4' visibility from the surface.

I'm not a diver -- nor even a very good swimmer. I do have a little pedal boat and tried doing a survey with a camera mounted to that. Ditto for a 3' long radio-controlled boat.

What I'd really like is something cheap that I could get a decent live view from as it is tethered under the pedal boat. I haven't tried the $3 USB endoscope cams I have a bunch of, which are waterproof, but they're definitely not great cameras. I also haven't tried the Olympus Toughs that I use on vacations in places that get wet, but can't get a live feed from them anyway. I also have some cheap plastic-bag type housings for my Sonys, but I generally only trust those for splash protection -- the best is a DICAPAC I used to use with my A55.

Suggestions?

Well, if the water level doesn't drop anymore I can tell you where exactly the leak is:

Its exactly on the water level