Pond survey camera suggestions?

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?

So basically yo need an underwater drone.   (Try asking about it in the drone forum here.  Maybe something exists, but if nothing else you might get some tips on what is needed to stream images back, still or video.

Speaking of video, is that more what you need here, or at you trying this with a collection of still images?

Just as a thought, due to the limited visibility, perhaps you could build a tripod rig with camera attached that you lower down on a line until it sits on the bottom, then using a remote release (or just timed shots perhaps with no user interaction), get shots from a camera that is pointed down and focused at the required distance.   Then, using a boat, just pull up the camera and drop it down onto another location.   Keep track of where the images are being taken if you can't review in real time.

PHXAZCRAIG wrote:

So basically yo need an underwater drone. (Try asking about it in the drone forum here. Maybe something exists, but if nothing else you might get some tips on what is needed to stream images back, still or video.

Good idea.

Speaking of video, is that more what you need here, or at you trying this with a collection of still images?

Just as a thought, due to the limited visibility, perhaps you could build a tripod rig with camera attached that you lower down on a line until it sits on the bottom, then using a remote release (or just timed shots perhaps with no user interaction), get shots from a camera that is pointed down and focused at the required distance. Then, using a boat, just pull up the camera and drop it down onto another location. Keep track of where the images are being taken if you can't review in real time.

My boat mount was simply a long clamp on the edge of the boat with the camera about 2' underwater. It wouldn't be hard to move the camera down further to trace the bottom (which isn't completely flat and has some obstructions, such as tree branches), except I don't want to risk hurting the liner by scraping the camera rig against it, so I at least want a live view to position the camera safely above the bottom. I suppose I could try using one of the $3 endoscope cameras just to watch for adjusting to follow the bottom and one of the other cameras to capture better images of what's there? I know a 1/2 acre pond doesn't sound big, but it's 21,780sqft, so optimistically assuming a 3ft view radius, a full survey would require 242 separate camera positions to be sampled!

I can probably use my GPS tracker to know where each sample was taken +/-3' or so.

Anyway, I was hoping somebody here would just say, "Here's how I did that." Not happening, eh? 

Someone recently asked about streaming video from some sort of underwater camera to be used at the edge of a pond. Nobody could figure a way to get the data off the camera while in use.

I'm thinking along these lines. This is out-of-the-box thinking, so anything that is impractical you need to re-engineer.

My concept for the rig itself is something fixed-focus at the peak of a small underwater tripod. The feet of the tripod can be big padded balls to protect the liner. Some sort of trigger mechanism is built into the rig that triggers a shot when the camera is on the bottom, perhaps by a pressure switch, perhaps a remote trigger. As for the type of camera you could use, I'm thinking a smart phone in a Kraken case ($299). I don't know how cell phone signals travel through water, but perhaps it may be able to stream far enough?

The rig might be built with some sort of lighting added to give the camera a chance s seeing something, especially if using video.

Above water you have alignment issues. I was thinking you might be able to mount strings across the top of the pond that you could use to align to as you moved a boat underneath them.

As for tree branches, are you prepared to perhaps try to remove them as you come upon them?

kelpdiver wrote:

https://www.bhphotovideo.com/c/buy/rovs/ci/25733/N/3877484839 - drones as low at 500, though with murky pond water, hard to know in advance if bright or dim lights are better. Better to borrow. Else, adjustable light power is an essential.

Wow. I had no idea you could get something like that for $500! Well, could if the $500 one was in stock.... That's probably the way to go.

When I built the ponds, I actually had the foresight to bury contacts under the liner so that I could measure resistance and from that deduce where a leak was, but the ground-level tops of those are not all intact 15 years later.

The expected leak is literally one or more chunks of liner missing thanks to a beaver. I had one piece of liner that is perhaps 2'x1' turn up on the shore... so I figure it came from somewhere. The soil under the pond has good clay content, but the pond does lie in a fold between two different rock types. A slow leak + evaporation would explain it all.

Kentucky is famous for it's limestone caves, and porous rock is under most of the area. Here's a satellite image of the area, my two ponds are the ones next to each other:

Rather famously, the big failed lake on the far left was 20' deep until one night about 25 years ago, when it literally emptied overnight. The failed pond to the right would be much larger if it filled (and the fence to my property would be underwater near the middle of it), but it has an average depth now of less than two feet (it's unusually high in this photo). In case you're wondering why I was foolish enough to build my two ponds between two failed ponds, the answer is that the upper one of mine was a swampy pond used to water cattle for 200 years, so I figured it was a pretty safe bet it would continue to hold at least some water... I always knew the lower one would be more of a risk, although it is still quite healthy despite the drop in level.

Both my ponds are fed entirely by runoff, and most of the runoff goes to the upper pond (to the right) and then overflows through a constructed waterfall into the lower -- so the lower pond naturally has a lot of level fluctuation. Unlike the upper pond, which has a small shallow area in the upper right and gets a fair amount of leaf litter, the lower pond has no shallows and just gets occasional branches in it from storms. Both my ponds should be 12' deep, and the upper one holds close to that, but the lower one has slowly dropped it's average depth from about 11' to more like 8' over a period of about 15 years; of course, level fluctuates a lot, with it still hitting 11' several times a year. Incidentally, there's a healthy population of sunfish and largemouth bass in each pond, and I've caught 6-pound bass in each.

BTW, if anybody has any suggestion for how to get a natural shoreline over the liner when the water level is fluctuating so much, I'd love to hear them....

I would like to know what the bottom of this pond actually is like.  Is it mostly just silt-covered liner?  Are there actual dead trees and bushes mucking things up?

If it is just a silt-covered liner, I would think there would be some obvious disturbance in the silt pattern nearby, unless it was quite deeply covered in silt.

PHXAZCRAIG wrote:

I would like to know what the bottom of this pond actually is like. Is it mostly just silt-covered liner? Are there actual dead trees and bushes mucking things up?

If it is just a silt-covered liner, I would think there would be some obvious disturbance in the silt pattern nearby, unless it was quite deeply covered in silt.

I think think the liner is quite clear. In fact, I see some folds in it that never flattened, and there are probably a few fishing lures hooked into the liner over the years (although they'd make very slow leaks, not sufficient to explain this).

Unlike the upper pond, the lower one has no shallow area, and most of the runoff coming into it is from the upper pond, so nothing really drags silt in. It also doesn't have a ton of willows around it shedding leaves into it. I think it's just got some random branches in it that fell in and sank, not much of that, but not nothing.

I have to say that the CHASING Dory Underwater Drone seems like a really great answer, as well as a fun toy to have around. I'd just have to convince my wife to spend $500 on yet another toy. 

BTW, I probably could drain the lower pond pretty easily, but I don't want to lose the fish population. I could probably do something collecting the fish (net? electro fishing?) and temporarily overcrowd the upper pond as long as I supplement the oxygen level. Of course, when I say "easily" I should note there's still close to a million gallons of water in it -- it would take blocking the overflow in, pumping it out for a week, and praying for no rain in that time. All of which is do-able.  Honestly, this might be the right answer because then we could reshape the pond a bit to make it more effective....  Not a cheap answer, but maybe right?

kelpdiver wrote:

SirHarry wrote:

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

Its exactly on the water level

not quite so simple.

Water level delta = water pouring in via waterfall - water lost to evaporation - water lost to leak.

Water lost to leak may be based on water pressure (depth), as well as water saturation underneath. Evaporation will vary on sunlight and humidity. Water intake varies on upstream supply. And if the drop took place over years, it's pretty subtle on day to day basis.

It holds steady for fairly long times, but also changes level as much as +/- a foot in a day. Really not consistent at all. I'm assuming that means there's probably a big hole in the liner somewhere and the clay below it is sort-of holding, but not consistently. The piece of liner I found washed on the shore is about 1'x2', which would certainly be enough to explain this....

BTW, I did say we're in a sinkhole area, right? It's quite possible it has a little sinkhole under it now... in which case it might be deeper than I thought, but in the wrong way.

Looking for a torn piece in the liner seems more straightforward, though with the murk and trees, still not an easy one. Can the water fall be closed off for a while to let water level decrease further?

Answered below... yes, but I don't want to kill the fish, so it's complicatd.

What would it cost to simply throw in a new liner?  Can you do that without draining it?

How about dangling a Gopro under a boat as you row around?

PHXAZCRAIG wrote:

What would it cost to simply throw in a new liner?

About $30K for the material alone. The liner is 1/3 acre in a single sheet that weighs a ton or two. No thanks.

The liner can be repaired even if it has a big hole without draining the pond. The catch is, I need to know exactly what the problem is (all the problems are) before I invest a $1K or more to fix it.

Can you do that without draining it?

Nope.

How about dangling a Gopro under a boat as you row around?

A bad approximation to what I've already tried with an iView 360 Pro and pedalboat.

Are fiber optic cameras waterproof?  Even if not, maybe stick one in a plastic bag well sealed, and drag it along under a boat watching a display above.

PHXAZCRAIG wrote:

Are fiber optic cameras waterproof? Even if not, maybe stick one in a plastic bag well sealed, and drag it along under a boat watching a display above.

That's basically what I can do with the $3 endoscope webcams....