How high can i rock pond wall


IPA

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I don’t follow what you are asking.
@GBBUDD This?
 
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What if I tried something like this where there is more than one rock on the very bottom and foamed the whole thing in. Is that workable, or would it still be very unsafe?
Each of those blue blocks is supposed to be a rock :).
Just remember that foam is not structural, it fails eventually. Your stones need to stay where you put them without any gloop holding them in place, because gloop fails eventually (by gloop, I mean mortar, glue, foam sealant, silicone, anything that one would use to glob between stones to make them stay in place when they are not stable on their own accord).

Never having done this in a pond, but having built several dry stack stone retaining walls, if I got stuck with the stone you have, I'd tilt the wall (dig out more, but at an angle, or backfill and pack to get a leaning wall) and then stagger the stones so each layer locks the layer below it in, sort of like shown below. I have tried to consider that you have more small round/square stones than good deep ones, you will still have to buy more longer stones to make this work and the angle may have to be tilted more. You should be able to stand on your stack and climb up it and it should stay. If it doesn't, it needs to be redone until it does. Also, like Mmathis said, if your soil is prone to splooging down over time, you may need more tilt and or more earthen shelves (a break in the line so you're stacking on earth instead of layer upon layer of stone). I live in a place where I can't use a shovel, I have to get out the pickax to dig a hole, nothing moves.
stone-stacking.jpg

That being said, I would just never do this. I'd consider it a waste of good stone. The stone will be mostly indistinguishable from a plain liner once the layer of algae grows on it and you can't scrub the algae off rocks once it's on them.

If I wanted the underwater stone look (if I liked the look of furry green rocks under the water), I might do just the first 1.5-2 feet, like this. I would be using flatter stones: we have a lot of slate around here and it's easy to work with, other than having to knapp the sharp edges off. This would also save you a ton of money on stone and not be a lot of additional work if you have 3-5 more feet you can extend outward from your current hole.
stone-stacking-half.jpg

The stone you have looks pretty irregular and hard to work with. Again, speaking as a stone retaining wall builder, not a pond builder, you ideally need lots of 1.5-2' long flat stones to interlock the smaller stones in the layers to really make a good solid structural wall, and it doesn't look like you have many of those. You can do it with more round/square/irregular stone, but it has to be a thicker wall (more horizontal depth of stone at the bottom, so you can stack it up into a triangle shape on itself) and you'd still need a few good longer flatter capstones to lock it all in at the top.

Someone who has built earthen stone rimmed ponds would probably be better able to draw the correct angle. I'm not sure how much the difference between the weight of stone in air versus in water comes into play in this case. My stone walls stay very solid on dry ground, but I can pick up a stone in the water three times the size of the biggest stone I can pick up on dry land and that has to come into play. The downward forces of each layer pin the ones below it into place, so I'm sure the math changes dramatically under water.

Many times when you see a stone wall with mortar, it's not actually structural, just a veneer, like shown below, which will fail, sometimes very quickly, sometimes it may take a while. There is such a thing as dye you can add to mortar to make it any color you like to match your stone. It's designed for indoor grout and may or may not be toxic to fish though.
Provia-1-700x1050.jpg
fakewall.jpg
 
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Anything you line the pond with will eventually get covered with a nice (and necessary) biofilm. It won't matter what color your stone or mortar presently are, it will all be covered.

Leave the rocks out and give the fish more room to swim.

I don't think using mortar is a very good idea. But, I'm not one for rocks in my pond either. Matter of opinion, I guess.

No pointy rocks are allowed anywhere near my pond, inside or out. Leaks are a real pain to locate, believe me. You don't want to be searching for a leak in the dead of Winter...been there....done that.
 
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I'm in no way an expert on stacking rocks, building stone walls, or the best way to contour a sloping interior pond edge, BUT! I will say that, as someone who's entire pond is lined in stone & gravel, I can *absolutely* see the colors & contours of my rock/gravel through the entire pond (down to the 3' + deepest area) Does the gravel darken & take on a bit of a green-ish hue over time? Yes. Does it all become one, solid, indistinguishable color? NO! I can absolutely see the variety of gravel on my pond bottom, as well as the variety of colors in stacked stone on the ledges & edges under water. It does not all look 'just like bare liner'. I have a couple of areas that the fish habitually rearrange the gravel, thus exposing an area of liner or fold (which I fix by redistributing the gravel to recover the exposed parts)

I realize that the whole 'gravel or no gravel on the bottom' is largely a matter of aesthetic opinion, but - bare liner vs rocked pond bottom does NOT look the same. It just doesn't.
 
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Thanks everyone for the very helpful replies. I have much to think on…

Maybe I should have started with a very basic and perhaps dumb question. I was so set on getting help out of the current dilemma (half the bottom of the pond rocked in and feeling frustrated because it didn’t feel like it was working) and I didn’t step back to ask it.

Would it work OK if I skipped the rock altogether to have the 40” – 48” sides with no rock – just liner. Or would that much of a vertical wall in clay soil be a very bad idea? As several folks have mentioned, I can go back in and backfill if that’s what is needed to get the sides more angled. But obviously if I can just rock around the top and move forward that would be preferable :D . My only thinking of adding the rock was it looked nice and it would help the clay from collapsing.

If I can just remove the rock out, keep the ~48" vertical clay walls behind the liner, and keep going then great! I'm OK with settling, I just don't want rocks up around the top/surface to cave in down the road... I was thinking adding in this rock wall would help prevent that sort of thing, but it seems like the overall concept is just a terrible idea with where things are at for me now.

Sorry if I’m a bit slow to all of this. I’m very emotionally involved with this whole project, and sometimes I may need to hear what I’m doing isn’t going to work a couple of times before it sinks in! I'm going to go back and re-read everyone's responses here again just to really let it sink in.

When I first started with the pond, I did have a bunch more shelves, but I removed them all thinking it would be more room for the fish... Sounds like that was a very bad idea and I really screwed up! Here's what it looked like earlier during excavation in the first picture. Then in the second picture you can see where it's at today before the carpet, underlayment, liner, and more underlayment. The second picture also shows where the bog is going to be on the top right.

20200531_192247.jpg
20200712_185704.jpg
 
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It's ok i think the videos show it and i think derek gets the idea
An Aquascape stepped terrace using smaller, rounder stones laid up against slanted edges:
View attachment 132456
This is what i was talking about minus one step as i would build a foot and a half per step rock up above the botom of each step to hold back river rock . nice job
 
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Maybe I should have started with a very basic and perhaps dumb question. I was so set on getting help out of the current dilemma (half the bottom of the pond rocked in and feeling frustrated because it didn’t feel like it was working) and I didn’t step back to ask it.
Would it work OK if I skipped the rock altogether to have the 40” – 48” sides with no rock – just liner. Or would that much of a vertical wall in clay soil be a very bad idea?

When I first started with the pond, I did have a bunch more shelves, but I removed them all thinking it would be more room for the fish... Sounds like that was a very bad idea and I really screwed up! Here's what it looked like earlier during excavation in the first picture.
I think I have to agree with you, sadly. The first hole looked much better with the shelves, much more stable. I'm not sure if the vertical wall will hold or not, I would err on the side of caution and say probably not. I would fill it back in to something similar to what you had before, that was a better design. You might could do one tier instead of two though, so long as it's walls are sloped (instead of upright like you had them).
 
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Maybe I should have started with a very basic and perhaps dumb question. I was so set on getting help out of the current dilemma (half the bottom of the pond rocked in and feeling frustrated because it didn’t feel like it was working) and I didn’t step back to ask it.
don't feel bad the ladies use to yell at us all the time not asking for directions . thank god for Garmin and now google maps .

The build looks good to me we just have to figure out how to rock the steep side. You can use Fabric like i showed in the video to move what we call two and three men boulders. a couple of those on the bottom would do the job or you can
rf.png
the yellow is where i would rebuild and extend the shelf thats off to the right bring that shelf acros to the left filling in the yellow area lessening the height . on theupper left side of photo 1 i would cut off the top of the concrete down about 6 inches if you have 10 inch rocks if you only have 6" rocks then make that top shelf a bout 3" so part of the rock is underwater and the other half is above " this looks natural. The other thing you can do where the height is 48" is to work that wall with flat rocks turned on edge that is how i built the walls in the begining of the video i shared above . and with foam between the rocks like you had mentioned .

i CAN SEE YOUR INENT WITH THE WATERFALL AREA instead or pulling appart your work you can always make damns so that when you place the rubber over your dig the steep areas that won't stay you lay the rubber over the damn / coral and have that hold the rocks from slipping . if you catch my drift. Fortunately for me i build better then i am at putting thoughts to words
 
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Finally found it - this is the video I was trying to go for. Has ~4-5ft tall shelves with mortared rock. About the same size rock as what I have - just need to remove some of the smaller stuff I think.


Anyone heard of a pinterest fail? That's kinda what my stuff looks like right now compared to Eric's 25+ years of experience!
 
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The pond digger is a good guy for sure . The only problem with all mortar like that is the cement is going to play with your ph it may help depending on your water or it may hurt. one tip for you if your buying sakrete or quickcrete from the depot or lowes buy a bag of portland cement and add a scoop or two two your mortar tub with the trowel it will make the concrete much stickier and easier to work with if you have some big voids don't be afraid of putting waterfall foam or even gravel filling in the spaces behind. while the intent is to have clear water and see your rocks and gravel quite often many live with just seeing the shape and never seeing the colors of the rocks in their ponds. The algae puts a film / peach fuzz over the rocks so a little mortar on the rocks may not be a game ender. If you want to clean it muratic acid can clean it right up with some elbow grease the fresher the easier it is to remove.
 
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What if I tried something like this where there is more than one rock on the very bottom and foamed the whole thing in. Is that workable, or would it still be very unsafe?

Each of those blue blocks is supposed to be a rock :).

I have watched probably over 200 hours of pond construction videos from Greg Whitstock, Pond Digger, Tussey, Jaak Harju, etc. I guess a lot of it didn't really sink in and get into my shoveling hands when we were going to town though....

View attachment 132436
The top of your wall needs to be stable enough that someone or something can walk on it... because eventually it will happen. One big rock is always going to be better at providing that stability than any combination of small rocks. Also - I know it's just a drawing, but you want that vertical wall to have a slight lean backwards.
 

addy1

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My pond is straight wall, with a tiny slant. Our dirt is clay with shale. Still holding well 10 years later. Here in MD

My pond in AZ I had straight walls, clay dirt and I put a lot of rock in bottom, after the first year could not even see the rocks. I did not do a clean out every year or vacuum the bottom. The algae nicely covered them and they just disappeared.
 
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The pond digger is a good guy for sure . The only problem with all mortar like that is the cement is going to play with your ph it may help depending on your water or it may hurt. one tip for you if your buying sakrete or quickcrete from the depot or lowes buy a bag of portland cement and add a scoop or two two your mortar tub with the trowel it will make the concrete much stickier and easier to work with if you have some big voids don't be afraid of putting waterfall foam or even gravel filling in the spaces behind. while the intent is to have clear water and see your rocks and gravel quite often many live with just seeing the shape and never seeing the colors of the rocks in their ponds. The algae puts a film / peach fuzz over the rocks so a little mortar on the rocks may not be a game ender. If you want to clean it muratic acid can clean it right up with some elbow grease the fresher the easier it is to remove.
GBBUDD,

Thanks for all the advice.

I think I am going to try and work on just a small section continuing with the mortar, adding in the waterfall foam and small gravel/river rock in the cracks as you suggest. I will try to take out some of the smaller rocks and introduce larger ones. I will also try to create a slant with the rock similar to some of the diagrams Phaewryn made (thanks for those).

If I can get this small area to work OK, then I’ll expand out and do the entire pond. If it doesn’t work well, then I’ll fall back to ripping everything out and backfilling with more dirt and trying to add back in a shelf behind the liner.

One other idea I had was to perhaps build a shelf inside with some retaining wall blocks and river rock (behind the blocks) to make maybe a 20inch tall shelf by 12 inches wide. More expensive for sure, but perhaps moving forward vs. ripping out underlayments, liner, carpet, mortar shell, etc….

Also, very good to hear Addy1 that your clay soil simply held up without any rock wall on the vertical at all. Good to know perhaps I am being too paranoid about the whole thing and rocks may not even be necessary. As Phaewryn pointed out, if the dirt wants to move it is going to move. Some crappy little rock wall of mine isn’t going to stop it :) . So the name of the game is what looks good, and what is safe for family and fish.

Thanks again everyone for your ideas!
 

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Finally found it - this is the video I was trying to go for. Has ~4-5ft tall shelves with mortared rock. About the same size rock as what I have - just need to remove some of the smaller stuff I think.


Anyone heard of a pinterest fail? That's kinda what my stuff looks like right now compared to Eric's 25+ years of experience!
The thought that always comes to my teeny little brain....yes, he did it, but he has an experience and knowledge level that I lack!

But all you can do is try it and see. Sure, it’s a PITA, but you can always go back and change or tweak things if it doesn’t work out.

One thing I have learned is that every pond is different. Every situation is different. What works for one may or may not work for the next guy or gal.

My motto is: look at the science, in this case, I guess that would be physics and fluid dynamics — consider the safety factor assess my own skill set, and since I am involved in Scouting, the Scout motto: “BE PREPARED!” Because when things go south, it always seems to happen at the most inconvenient time!
 
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I don't see the need to rock from the bottom of the pond to the top. You are taking up a lot of space with that and I'm sure the fish could use it. Also, fish can get hurt on sharp rocks and I have lost some females during spawning that got beaten up on rocks, and I don't have any on the walls like your illustration. Mine are like mmathis' and just from the shelf up.

The liner is not that visible, especially when algae covers it all. And the plants in the pond will be much more of a focus, not the liner. Personally, I would save the money and the effort and not use rocks that way. Just my 2 cents worth.
 
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Mmathis – I guess you are correct there. Hopefully this will work for me. It will certainly look in no way, shape, or form as good as PondDigger’s mortar job .

WaterGardener – My original thinking was I needed to do the rock walls to help support the clay sides from caving in. The is largely my fault as I screwed up the excavation by trying to make more room for the fish. There is no real upper shelf for rocks in the current state ☹. So, if I don’t do the wall I won’t be able to do coping stones. If I had a time machine, I would probably dig the shelves properly like everyone is telling me, not do any rocks in the pond, and have a real nice top shelf for coping stones. I’m sort of trying to salvage what I’ve done here vs. rip everything out and start almost over from the beginning. Time will tell if the idea of pushing forward is a good one or a terrible idea. Plus I have ~14.5 tons of rock in my driveway and small backyard, so I have to put the rock somewhere ! Below is a picture of the rock pile as it was delivered. If it does work out and I end up rocking the whole pond, I will try to pick out rocks for under water which are as smooth as I can find from the pile.

temp.jpg
 
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Should have asked to see what stone you had to work with i see many rock there 4 times the size i thought you had. you should be fine. if you put some medium sized on the bottom pulled out a little put gravel and concrete behind the first row and build from there your largest next mix and match as you go and you should be fine they do sell boulder baskets its a nylon weave with handles for a two man or four man lift you could use those or use some fabric.
good luck
 
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Thanks guys! That instills a bit more confidence :D !

The super big ones are simply too heavy to lower by hand (or sheet/tarp), but I think we can find a way to get the ~120lb ones down in the hole. We tried a couple using a tarp, and my wife and I can barely move them. Some are too heavy to move with a tarp at all, I had to use a dolly to get them from the driveway to the lagging area. The really big one (you cannot really see it in this picture) I calculated is about ~920 lbs! No idea what we'll do with that one - maybe put in the stream which will connect the swim pond to the fish pond (2021 work).

WaterGardener - we are thinking alike! I was thinking of saving the biggest ones for around the waterfall, but sounds like I had it bass ackwards. We can get a couple medium or medium/large down there like GBBUDD said and see what happens! Then we can do some of the ones which are too large to safely move down into the hole and muscle them in place for the waterfalls.

Here's a picture of the huge rock. I can just barely nudge it along half an inch at a time with a 5 foot long 2x4 board using it as a lever.
20200717_172011.jpg
 

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