Collapsing Pond Wall Repair

Recently on one of our pond cleans we had an incident where the rear wall of the pond collapsed while we were pumping the water out of the pond.

This pond has a hidden problem which we discovered when we attempted to clean it!

As we were pumping the water out the back wall shifted and then the stones collapsed into the pond .As the water got lower more of the wall came down.

As the water got lower more of the wall caved in!

This was a very unusal problem as it was only along the backwall and not anywheres else. When the pond was almost empty my first clue begain to emerge. In the bottom of the pond there were three large bubbles in the liner. When you stepped on the bubbles it was like stepping on a water bed. So there was water trapped under the liner in the pond hole.

The question now became where was the water coming from. I examined the liner and the waterfall but could not find any tears or leaks. It took a while of looking but I finally found the problem.

Three large water bubbles trapped under the pond liner .

When the pond was built the area it was installed in at the corner of the yard backed up to some wooded property. The backyard was lower than the adjacent property so every time it rained the wooded property was draining towards the pond. The rain water worked it’s way down under the lip of the liner and washed the soil away so when the water got trapped under the pond it bubbled pulled the liner down as it bubbled up. As the pond was drained there was nothing holding the rock to the side of the pond so it shifted and it collapsed.

Hydrostatic pressure is very powerful and can work all kinds of strange problems like pushing a pond liner up when there is a pond full of water on top of it. Once this problem was diagnosed I came up with a two part solution to the problem.

The first problem was to get the water out from under the liner. I pulled the liner back from the wall where it had collapsed and snaked a suction hose from a pump down to the bottom and kept pushing the water down to the low point until I was able to pump all the water from below the liner.

The next step was to remove the rest of the back wall rocks and then back fill the area behind the liner. I then raised the the lip and graded the area so the water would flow away from the pond. Once this was done I was able to pull the liner back up into place and rebuild the wall.

This was a time consuming process and cost the homeowner money that did not need to be spent had the area where the pond was to be installed been checked first . That is why it is important before locating a pond site that you are sure of the surrounding area and any problems it could create.

The collapsed wall was repaired and the pond cleaned and refilled.

The pond was repaired and the fish were happy to get back home after a couple of days in a holding tank. But a better job of pre-planning could have prevented the problem to begin with.