Alder Burns wrote:Unless you've got really good clay content....like water stands by itself overnight in your test hole, sealing your pond without a liner is going to be a huge, iffy project. Even with good clay content you've got to compact the clay, something ordinarily done with the weight of heavy machinery on larger ponds. Look up bentonite and gley.
You can make the pond deeper, relative to the size, if you use a liner, since the water will push against the liner and hold the banks at a steeper angle. Without a liner you will have to figure out the angle of repose for the material...usually no steeper than 2:1 (run:rise). The carpet-sandwich technique would enable you to line a pond of this size pretty cheaply, and probably more quickly than any non-liner technique, especially without heavy machinery....
Justin Hitt wrote:Levente,
In the design of a pond down slope from my house that was to be deeper than it is wide -- there came up a number of issues similar to what Alder brings up.
For instance, as he mentioned with slope of banks. If you have a deep pond with near vertical sides, then use a liner, being down hill you can have issue with runoff getting behind the liner. Depending on the type of soil you may need to step pond down to depth, or reinforce walls.
Water just can't run down a hill into the pond. It will need to be collected then drained from a higher elevation via pipe to prevent seepage near structure. Using it to hold rainwater from roof you'll want to run drains all the way to pond area (or collect into a sump then via larger pipe to pond.)
You may want to have someone who builds koi ponds, or does in-ground vinyl swimming pools to come out with some estimates. You could end up with a nasty mess, or larger erosion issues if you just dig a hole. It may have too much water some seasons, very little water in others.
If you're going to use the pond for fish you may not want roof runoff in your pond without first going through a marsh or retention pond. Be more specific about what you want this pond to do, look at existing designs. Pond usage has huge impact on design.
For my project I'm going to need to revisit a lot of things and have moved it down my priority list because of some serious safety issues you can face with a deep pond.
Brenda Groth wrote:any pond needs a gentle slope on one side for critters that fall in ..to be able to climb out...but anything shallower than a few feet deep will fill up quickly with cattails and weeds if there is seed in your area..so deeper better..
i agree with the mentions above..smaller ponds tend to not really hold much water..unless they have been compacted or lined..due to evaporation and leakage.
you can visit my blog (below) and check out the pond I have..it is much larger than you are describing, and the shallow areas are all filled with plants..all brought in by nature except the water lilies.
ledges are great for planting plants..and do help give a foothold to critters.
Levente Andras wrote:You mention reinforced walls - can you suggest any specific techniques? I'm strongly in favour of methods that don't involve synthetic materials