Retaining wall

[jclements]

Excavators came on Friday to dig our pond. Our back yard slopes down as you approach the corner of the fence. Here is the view from our drive way (pond is where swing set used to be).



Here's another view of the slope.



This is our pond shape/design. The bog is closest to the corner of the fence:



And here's the actual hole!



In the last photo, notice that the ground is about 2' lower in the left back corner than in the front right corner. We've decided to dig down on the high edge 10.5" and then bring up the back edge about 12". We will need either a concrete wall or collar that runs from the front left around to the back right, and it will be about 12" high at the tallest part. DH and I are considering cynder blocks filled with rebar and concrete (backfilled with clay soil), but are unsure about stabilizing/reinforcing them against the pressure that will be exerted from the pond. Would it be better to make forms and fill it in? Any suggestions?

Many thanks in advance!!

[KatFish]

I can't answer your question, but it's looking good! 

[Sunbeam56]

Its easier to get a smooth surface on a curved plane with a formed wall. Cinder blocks, being in staight sections don't make curves very well. It can be done, its just irregular.
As shallow as your pond is = twelve inches and not twelve feet? - there is no diffference structurally.

[jclements]

The wall will only need to be 12" above current ground level in the back left corner to make the water surface level across the hole. I have seen some pretty good examples of curved walls with block and was leaning that way because it's not so permanent...meaning we can change something before we set it whereas once forms are filled, it's done.

Block or form, how wide should the wall be in order to keep strong against the force of the water?

[Sunbeam56]

Is this a liner pond?
Cinderblocks are 8 inches wide. If you are thinking you will change it, fill the holes in the blocks with wet sand, packed down.
If you decide to pour a wall, you will need at least 4 inches thick.
Not necessarily because you need that much concrete, but because its too awkward to build any smaller.
And, yeah - its a lot harder to move later - as it, it won't move, drag out the sledgehammers and sunscreen....

[Kat]

I know there are a ton of pond build posts on Koiphen, but this one might interest you as it is local.

http://www.dfwfishbox.com/forums/production/showthread.php?t=11570

[Pondering]

How exciting!    I remember what that felt like last year when we broke ground.  Now i don't know what we did with all our time before the pond.     Can't wait to see the progress!