Newbie: Building a retaining wall w. pondless waterfall

[TechieTechie]

Hi all....

In the midst a major yard renovation (the low spot in my yard is about a foot lower that the neighbor's driveway and my house). So, my contractor is building a small 16" retaining wall to address the height difference between the patio and the new yard.

I wanted a small elegant pondless waterfall, but instead got an overly large, too deep, hippo'ed and volanco'ed water feature. When I took out the stock tank, I pumped out at least 60 gallons of standing water under the shell. Not to mention the wall was basically 57 gravel....so I've torn both out and am rebuilding them

I would prefer to keep the wall separate from the pond (so that in case either needs rebuilt, I'm not tearing apart two things. Which means NOT running the EPDM liner under the wall (which is dry stacked standstone, heavy). I've done most, if not all of the recommended techniques. Level sand base, geotextile (a very thin indoor/outdoor rug, actually), 2 layers of 45ml EPDM, 2" sand (well, fine sandstone screening, aka 10) between the EPDM/rug pond wall and the 57 gravel wall base (w. more 10 screening on top).

The top of the milk crates will sit about even with the top of the sunken 1st course of the wall. Or, the top of the crates sit about 4 inches above the wall base.

The two big questions are:

1. Do I make the first course of the wall deep enough to butt up against the water feature? I'm thinking no, slightly offset (7" or so). Less chance of tearing the liner.
2. Thinking I'll use a formal row of stone at the base of the wall to tuck in the line. Even if I have to make it 2 courses high. I have PLENTY of stone to play with


I want it to look like a combination of pics 2 and 3. First is the feature I tore down.

Thanks!

 

[j.w]

@TechieTechie
Never made one of those so can't help ya there!

 

[hamstermann]

Wow, those look really nice! I'm not a construction expert but @GBBUDD is. Maybe he can advise you.

 

[TechieTechie]

Thank you....what I really want is the elegance and design of pic 1, with the 2nd 'waterfall' like in pic 2.

Another question, is there a preferred waterfall height/ratio to maximize water falling noise but minimizing backsplash? The top of the wall (including the capstone) is planned only to be 16". I'm wondering if I need the 2nd waterfall 'layer'.

 

[TechieTechie]

The initial dig/layout and after 2 days of wall build...

 

[GBBUDD]

not realy understanding your build. if your having water run down over the retaining wall like the picture above you will need to put a liner behind and under the wall. they don't all need to be the same piece of rubber or liner but they do have to be about a 6 inch overlap if there is not going to be a seam. and that overlap needs to be above the water line.
from what your building it should have the hole / deepest part come up to the top and run under the rock walls , if there is going to be any kind of waterfall then that should be bent vertically behind the wall and from there you could do a second piece.
i don't believe your thinking or t least what I'm interpreting from your post is going to work

 

[TechieTechie]

not realy understanding your build. if your having water run down over the retaining wall like the picture above you will need to put a liner behind and under the wall. they don't all need to be the same piece of rubber or liner but they do have to be about a 6 inch overlap if there is not going to be a seam. and that overlap needs to be above the water line.
from what your building it should have the hole / deepest part come up to the top and run under the rock walls , if there is going to be any kind of waterfall then that should be bent vertically behind the wall and from there you could do a second piece.
i don't believe your thinking or t least what I'm interpreting from your post is going to work

GB, I love the idea about a 2nd liner running behind the wall. I already have 2 liners in the pond portion (for durability)...I can run the 'upper' or topmost liner under the wall and keep the lower one folded under on the pond side of the wall. That way, in case the weight of the rocks tears one liner, I still have the lower liner intact.

I'm hoping to position the 'spout' far enough over the pond that there is little splashback on the wall....but this is good insurance.

Thank you thank you thank you

 

[GBBUDD]

stopping splash is impossible but you can limit it. if you picture a ski jump and it has a flat landing with a straight up and down jump when you land you got splat . if the jump has an angled landing like a ski jump you can land with little
"splat" so if the falls drop onto a flat rock or even the water it goes "splat" make the water land on the angled rock and little splatter and little sound.

option 2 is to have the water land below the area around it kinda like falling into a sink hole with rocks surrounding it and making like a foot deep area little splash will get out of that

as far as two layers of liner , you would think it makes sense but in actuality it usually causes more problems then solves . for one we call it the hippo. where water gets under a liner and then takes the path of least resistance like all of nature.

what you want to do is make a sandwich a good underlayment under the liner and equally a good layer on top but both that do not hold water but stop rocks and sticks etc from getting to the liner and creating water loss. non woven polyethylene geotextile 8 oz to start with imo in any soils that do have a remote chance to poke the liner. they do come much heavier for areas that are full of sharp rocks.

equally you don't use extra liner in a different piece to prevent pulling of the liner you leave slack so if something does settle there is material there to allow it to move

i can keep going and going but it is all in my showcase below i suggest you go have a look