Leak detection and repair?

[AussieGardener]

Hello everyone,

3 pics of our new pond. We must have a leak, as the water level quickly settles back down to this level, and then stops there (or slows way down). You can see the overflow pipe - it was designed of course to have water come right up to that level.

It looks like I have tons of rocks to remove in order to expose the rubber liner in the search for the leak. Has anyone been through this exercise before, and if so.... Are there any shortcuts that you know of? This will be a LOT of work.

I had a crew helping me with the pond build, once I had placed the liner (hauling and landing the stones). So I can't know how carefully they treated the liner at all times, while they were placing them.

 

[combatwombat]

Bummer. And yes, pretty much everyone here has been where you are now. You'll get through it.

No waterfall, correct? What about pump plumbing? All inside the pond or does it travel out of the liner?

I think I'd start by filling it above the leak point and squirting 10-20 ml of milk every 5 feet or so around the edge as water level is leaking back down. If it's a large leak like you describe, I'd expect to see the milk at one of the points start to migrate towards the leak location.

 

[Jhn]

Typeof soil under the liner? Did you add non woven underlay Over and under liner?

To add would check under the larger rocks first, if one of them sat on a small piece of gravel and was being stepped on/moved abit as the pond was being rocked it will cut through liner fairly easily.

If it’s not in the plumbing as @combatwombat suggested then there are no short cuts, just need to methodically remove rock and search at the water line. It’s just work, it can be solved and fixed.

 

[Lisak1]

Well the good news is you only have to check above the waterline - everything below is clearly holding water. So it could be worse.

I would start by checking around the perimeter of the pond for areas that are wet - that water is going somewhere. You may have to dig down a bit to find it, or it just might be a bit mushy in a spot.

If that doesn't reveal the problem area, I would plan to spend a few hours just observing. Fill the pond to the top and then slowly circle, looking very closely for water that is moving in a pattern or direction it should not be. If the leak is big enough you might be able to detect water movement.

If those ideas both fail, then I guess you climb in and start moving rocks. Is the whole interior of the pond rocked?

 

[AussieGardener]

Thanks CombatWombat, Jhn, and Lisak1.

I am chuckling at something - I have IN FACT been in combat with a wombat. I can only guess at the year - probably around 1981.. visiting a mate in East Gippsland (Victoria, Australia), and there was a resident wombat under the floor of the shack. It would muscle its way inside looking for treats, and I got into a 'pushing match' - this guy could push me across the floor! (Haydn warned me to be careful of getting bit). So there you are.... a little entertainment with your Sunday cup of tea. No wombats in Maryland USA.

This pond build is still at 'phase 1 - it's just geotextile fabric, rubber liner, and the rocks. Oh, I did also add an overflow. The excavation was made with a pretty decent 'shelf' to land larger rocks, and provide a habitat for frogs and aquatic plants. I remember at some point during the build being concerned that the guys I had hired to help me were inside the pond with their construction boots on, but we were in the process of moving tons of rock, so much going on at once.

Really appreciate all the great thinking, and perhaps best of all the reassurances that I will get this licked. What I can do is get in there, start peeling back the rocks to reveal the water line (I probably need to move about 2 tons of material), and then I can fill slightly past the estimated leak point... the water level is going to drop below it as I eliminate the displacement volume of all currently submerged rock material.

If I fill back up to where I estimate the current water level to be (sans rocks), I can just let it fall and see where we get to. I will provide some updates. I'm keen to get on this now, because we have a vastly entertaining population of frogs here, at least 2 or 3 species, and I want to get this all sorted out for them in time for Spring. (I have mentioned these guys in some other posts, and in the middle of summer, they make so much noise overnight I really thought we might get noise complaints from our community).

Have a great day!

 

[AussieGardener]

5 mins after posting, I just came up with a water-conserving tweak - I can stabilize a vertical post in the center of the pond, marking the water level, before I commence removing rocks. I should be able to translate the mark over to the edge, and know, within say a ½" where to be looking for the leak.

Photos to follow.

Oh, to address some points I neglected from prior ideas - this is a straight clay soil, has parent rocks and stones embedded into it, including mica, which can be fascinating to look at. So yes, opportunities for unfortunate contact and pressure between underlying and overlying stones. The geotextile liner is good quality, and I hope that it is providing a good level of protection agains that type of puncture hazard. I will do as suggested by Jhn and focus first on the areas that housed the biggest rocks. Thanks again...

 

[GBBUDD]

resident wombat under the floor of the shack. It would muscle its way inside looking for treats

sOUNDS LIKE OUR WOMBAT TOO. I'VE BEEN BIT A COUPLE TIMES

can stabilize a vertical post in the center of the pond, marking the water

TAKE SOME STRING and drape it over the edge bring it down to the water line. That or a paint marker and mark your rocks odds of putting them back exactly are pretty slim.

Take a pencil with an eraser and poke at the liner with the eraser, if you soil softens when wet you may get lucky

 

[Jhn]

@AussieGardener patience and being thorough you will find the leak. As was mentioned all of us have had to deal with leaks and water escaping issues, all can be solved.
Had a leak issue on my pond addition that took a couple weeks to find the leak, just takes patience.

 

[combatwombat]

sOUNDS LIKE OUR WOMBAT TOO. I'VE BEEN BIT A COUPLE TIMES