Do I need to build an interior support wall for my waterfall "hill?"

Discussion in 'Pond Construction & Equipment' started by bagsmom, May 9, 2014.

  1. bagsmom

    bagsmom

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    Howdy, Pond Experts! My pond is still safely in my brain. No money saved yet to purchase supplies -- but I'm planning. I have a stone wall against which I'd like to build up the earth and put in a waterfall. It will only be about 3 to 4 feet tall. I'll do stone and such, with some moss and ferns. I have a bunch of the old rocks -- same ones used to build the wall 70+ years ago. It should blend in nicely. Question is: should I use cinder blocks or something to make an interior support for the waterfall "hill?" Or just use dirt and rocks? My worry is that the hill will erode with rain. The ground is not naturally sloped, so I'm creating my own raised spot. What are your thoughts? I'd appreciate your expertise! I'm really having fun lurking around on here and reading! Thank you!
     
    bagsmom, May 9, 2014
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  2. bagsmom

    Waterbug

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    Kind of hard to say without more info. Pics, measurements, type of soil, drawn plan and also your goal for lifespan of the structure. But in general concrete reinforced walls are the standard for retaining walls.

    Dry stacked stone retaining wall 3-4' is very doable but is generally more expensive, or more work. There are great instructions/videos online for building dry stacked retaining walls. People have been doing it for about 5500 years so there's a lot of know how available.

    You can also do a combo where you use block for the waterfall base and dry stacked stone up to the block. The trick imo is to make sure you set the waterfall back far enough. It's easy to add rock to a waterfall that's set too far back. Too far forward doesn't look very natural to me, unless you want a formal look but that doesn'y sound like the case.
     
    Waterbug, May 9, 2014
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  3. bagsmom

    bagsmom

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    I need to dig around in IPhoto and get my pix out again. I posted some on here before. The pond will be small. Just about 8 x 11 feet. I only need the waterfall up off the ground enough to make a pleasant little babble and trickle -- so not Niagra or anything! :) The long stone retaining wall exists between my and my neighbor's terraced property lots. I thought having the waterfall up against the wall would look nice. I'll have a 4 foot long stream from the waterfall to the pond. So needless to say, I need to raise up the ground level and slope it from little waterfall to the pond. I've read in a lot of books that just dirt is ok. But it seems like erosion would be inevitable. I want the pond to last as long as possible! OK -- found my photo and rough sketch. You can see the long retaining wall between properties. I know I'll be losing / moving a lot of my plants, including a redbud there that's not very healthy anyway. You can see where I want to build up the waterfall against that wall. pond sketch.JPG
     
    bagsmom, May 9, 2014
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  4. bagsmom

    randythawkins

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    randythawkins, May 9, 2014
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  5. bagsmom

    Waterbug

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    I think I understand now. I thought you were build a new wall to match the old. So you're just putting the waterfall up against the existing wall.

    Yes, concrete block is the way to form the basic falls shape, then EPDM liner, then rocks.

    If you really want this to last as long as possible the correct way is to dig down below the frost line. Your local building department can tell you how deep. Not sure where you live but it looks like a cold area. When you dig down you want to flatten the soil but only by removing soil. You don't want to put soil back in and tamp id down. Then you pour a concrete footer with rebar. There's instruction on the web if you decide to go that way, search "concrete footer". Then the block goes on top of that with vertical rebar tying the block to the footer. You fill the blocks with concrete. Horizontal rebar maybe mid course, use "bond beam" blocks in that course. Personally I just use bond beam for all the blocks, just easier when buying. A waterfall doesn't take many blocks.

    You can fill in with rocks, stone, broken concrete, gravel. Dirt isn't good because it expands when it freezes. Plus it settles. Commonly waterfalls leak and often because of settling. The extra digging and material cost really isn't a lot because it's a really small structure.

    Make sure you plan ahead for where the pipe to the falls will go.

    Everything can be scaled back, but risk go up and lifespan is likely reduced. Most people, even professional pond builders which is a little shocking, never do anything close to a proper foundation. Mounding soil is very fast, easy and common and will generally last long enough (year or two) that the owner won't go after the builder.

    No way to predict how long mounded soil would last, but I'd expect problems pretty quick.But they can be tweaked. Settling is the main enemy. Erosion can be spotted and fixed normally.

    Interestingly when waterfalls are built in the swimming pool trade they virtually always are built will a proper foundation. They're in a trade that gets inspected a lot so they're used to building correctly. In the pond trade it only has to last long enough for the check to clear.

    If you decide to go that way you can draw plans and post for tips.
     
    Waterbug, May 9, 2014
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  6. bagsmom

    bagsmom

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    Thanks Randy and Waterbug! Yes, Randy -- I saw your thread and was very impressed! What you are doing is way more extensive, but I love to see the work and know I can learn from it! Waterbug -- I'm in GA, so no frostline to deal with. Also, we have nasty concrete-like red clay, which will be a you-know-what to dig, but will actually provide a really solid surface! Thank you for all the information. It's going to take me a long time to save money for what I want to do, but on the plus side, it will give me time to research and plan!
     
    bagsmom, May 9, 2014
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  7. bagsmom

    sissy sissy

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    Hope you are putting in more than 1 outlet ,If you are paying for it get enough put in .Make sure that they are on there own breakers ..I have 2 breakers for my pond and 2 breakers for my outside lights .This way if they are not on I know it is only those items that could have tripped the breakers .I used retaining wall block cheapest and easiest for a home owner to do .Bigger rocks can be hard to handle .Liner is expensive but pumps you need to research .I went with laguna 4 year warranty and lowest energy use i could find on in pond one .Some externals use less but you do have to protect them .When you order you liner remember there are shipping costs .Dr foster and smith did not charge me the 7.99 for shipping .Other places charge a lot of money .You may be able to use rubber roofing or find a local company
     
    sissy, May 9, 2014
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  8. bagsmom

    Waterbug

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    I'm in Phoenix AZ and our "frost line" is 12". "Forst line" is kind of a poor term, but that's what most DIYer use. Each city/county/or state defines how far down a footer has to be. This might have to do with local wind conditions, or 100 year frost line, or soil type. My guess is in GA it's 12-18", but your local building department will tell you for free by phone. Can also find it via Google probably.

    Yes, if the code says 12" and you only want to go 10" it probably won't make a difference. But you said "I want the pond to last as long as possible!". The way we do that is by following local code. It's based on more info than I'll ever know so I don't second guess it. I'm not saying you shouldn't cut corners, I do it all the time for things that don't need to be to code like small waterfalls. It's just the lifespan thing you mentioned.
     
    Waterbug, May 9, 2014
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  9. bagsmom

    bagsmom

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    Thanks everyone! This is all such helpful information!
     
    bagsmom, May 10, 2014
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