Help - retaining wall? Or Wait? Chill?

[Mmathis]

To start out, you might want to read my recent thread below, which gives a brief explanation.

https://www.gardenpondforum.com/threads/creeping-sides-of-pond-wall.13534/

I know I made the mistake of trying to take on this job during the wrong time of year, but was desperate [no, actually, impatient....] to have it finished by spring. That drive, plus some insistence by hubby that I "get it finished," probably contributed -- time was NOT my friend.

A big section of the new wall I was building has collapsed after a day of rain! I was at the stage of trimming down & compacting the berm -- almost there! Almost there! As soon as I can get the pic to move over from my iPhone, I'll post the pic. OK, so the pic is there now. Please excuse my sloppy work area! Green is where the coping shelf USED to be. Red circle is where the coping shelf is NOW.

1. With the wall down and water [rain + groundwater] in the hole, IS THERE ANY WAY POSSIBLE TO PROCEED WITH THIS PROJECT FOR NOW? [see my final comment*] Or do I just need to CHILL, and wait for spring?
2. My only issue with waiting is that I have the liner pulled back and the fish are living in the other side with about 1/2 of the usual water depth -- with cold weather still ahead, I'm concerned about water temp.
3. If / when I do finish the wall, should I build it up behind a retaining wall? The wall is about 2-1/2' to 3' tall from the coping shelf. Advice for retaining wall construction is welcomed, as well....

*Hubby wants to do this project over the w/end...... I'm against it. There is nothing but water and mush on the "floor", and I don't see how it's possible. He wants to do a cinder block retaining wall, but I don't see how it's possible to get it anchored & stable in the mush. Even when the rain stops, the groundwater issue is such that we can pump for days and never get it really dried out.
HELP!

 

[sissy]

concrete can be done and you can use rebar pounded into the ground and back filled with dirt tamped down hard in each block as you set it .My pond is a double wall pond .The inside is concrete block stacked 2 high back filled each block with dirt and then pounded the rebar in and it has held up for 11 yeas now .My outside wall is the retaining wall block .Can't figure out how to access my old pics to show inside wall verses out side wall .Liner lays over inside wall .Out side wall is just for looks

 

[Mmathis]

concrete can be done and you can use rebar pounded into the ground and back filled with dirt tamped down hard in each block as you set it .My pond is a double wall pond .The inside is concrete block stacked 2 high back filled each block with dirt and then pounded the rebar in and it has held up for 11 yeas now .My outside wall is the retaining wall block .Can't figure out how to access my old pics to show inside wall verses out side wall .Liner lays over inside wall .Out side wall is just for looks

Sissy, hoping you can figure out the pictures! But is this something that can be done with wet ground?

Here's a pic of how I did the build-in-progress, new "turtle-bog." I think I stacked the blocks 3-high and used rebar, as well. Is this similar to what you did?

 

[sissy]

Well my block was only 2 high and higher I would think you would need concrete to fill blocks and rebar my pics I had stored in the extra media thing on here I can't find a link to it .I did not have a digital camera when I built it and never thought about pics

 

[DrDave]

If your fish are small, you might want to move the fish into a large trash can lined with a new plastic bag to protect them during construction. Add an airstone and a small circulating pump.

 

[Big Lou]

If you have true full time ground water issues then I'm afraid that problem is not going away. I have a few questions. Does your liner lay atop the mushy bottom or what? If your liner is on a solid base I can only assume you somehow backfill over the mush. Back to your retaining wall. With the mush a given I suggest you hire a excavator or engineer to find a solution. One thought I have is to drive pilings through past the ground water to a solid base. With the pilings in place a building a concrete waterproofed retaining wall MAY be possible.

Here's an alternative. Shooting in the dark so excuse my dream works. In the ground water area backfill replicating the natural soil formation. This would necessitate that area being higher than the other sides. To compensate your pondscaping/landscaping skills will be challenged. The higher side needs to look as if it is natural.

Your problem is quite challenging. If you rush to a hasty solution there could be even more unexpected challenges in the future. Best to find a true solution now. Best luck to you and yours.

 

[Mmathis]

If your fish are small, you might want to move the fish into a large trash can lined with a new plastic bag to protect them during construction. Add an airstone and a small circulating pump.

That is a good consideration. But the way I have the liner pulled back and supported is pretty secure for them. They are in 500 or so gallons of the pond water. I do have air stones and still have my SKIPPY going [turned down a little] as well as the spitter pump.

Since this project is obviously going to take longer than planned, I'd be afraid to move them to a "temporary" holding area as they might be there a while. And with colder weather on the horizon [and this is a concern] I think they're pretty safe there, but I will keep this in mind.

 

[Mmathis]

If you have true full time ground water issues then I'm afraid that problem is not going away. I have a few questions. Does your liner lay atop the mushy bottom or what? If your liner is on a solid base I can only assume you somehow backfill over the mush. Back to your retaining wall. With the mush a given I suggest you hire a excavator or engineer to find a solution. One thought I have is to drive pilings through past the ground water to a solid base. With the pilings in place a building a concrete waterproofed retaining wall MAY be possible.

Here's an alternative. Shooting in the dark so excuse my dream works. In the ground water area backfill replicating the natural soil formation. This would necessitate that area being higher than the other sides. To compensate your pondscaping/landscaping skills will be challenged. The higher side needs to look as if it is natural.

Your problem is quite challenging. If you rush to a hasty solution there could be even more unexpected challenges in the future. Best to find a true solution now. Best luck to you and yours.

Hey, Big Lou! Thanks for the input! When we dug the pond back in 2012, we hit this problem, but since it was spring/summer, it wasn't bad and we were able to deal with the water. That was a dry year. It's been wetter since then.

I have worried about the groundwater pushing up on the liner, but so far that hasn't happened. Maybe it's 'cause we have thick clay and maybe that helps hold on to the liner. Don't know. Keeping fingers crossed!

But the problem here is: when I took out the side of the pond that was designated as the "turtle bog" [and was integrated into the turtle habitat], I wanted to deepen that side [it was around 18" sloping to maybe 24"]. I also wanted to fill in part of the side of the pond, making the pond a little narrower, and make some solid ground on the outside so we could walk there and the pond wouldn't be just right up to the turtle fence.

We made a temp retaining wall and backfilled it with the dirt coming from the pond bottom [making the pond deeper]. Was able to pump out enough of the groundwater each day to make a good work area. Had been tamping and compacting the soil behind the retaining wall and got to the point of carving out the coping shelf. Then took down the retaining wall -- probably too soon. Then it rained.


Trying to remember what I was doing with this pic....but it might give an idea. The green is the OLD pond edge as it was [have moved the turtle fence back]. The yellow is where I dug to deepen the pond. The blue must be the NEW pond edge that was filled in -- the margin where the blue and yellow meet is the actual edge, where the collapse took place.

 

[sissy]

try to show double wall the best i can do today .Liner is to stiff to move today .The inside wall is where the black liner is over the concrete block and out side wall is the retaining wall block Between the 2 are big rocks to allow water to flow and not freeze .Best I could show it

 

[Big Lou]

Again, I wish you the best luck. I think we all can learn from your situation.

 

[sissy]

I agree lou and I worry everytime we get the really hard rains because you never know when something can happen .Even with freezing weather it worries me .I think all ponders feel the same way .I just hope that all the rain they are calling for will not cause more problems

 

[sissy]

I put the board on top of my concrete block wall with boards attached to the side of it that actually cover the pond liner and hold it all in place ,the salt treated board on top is a 2x12 and the board on the out side of the concrete block is screwed into the top board and is deck boards .Shaped like an L .big part of the L(2x12) is on top and deck board on the outside of the small part of the L.I wish I could describe it better

 

[sissy]

I took the small piece by the over flow off the side .Last pic you can see some of my bridge that sets on top of the top board.I put 2 pieces of green board under the bridge feet so you could see the bridge feet ,that way that shows it is the top board