Digging a pond at home, hit groundwater

Discussion in 'Water Features' started by DragonflyGardening, Mar 26, 2012.

  1. DragonflyGardening

    DragonflyGardening LawnSite Member
    Messages: 47

    Hi guys, thought I would look for some advice. I have a perfect spot to build a pond - right beside the deck there is a small (5' or so) slope leading down to a nice glen beside the vegetable garden...it's probably the most private spot on the property and really ideal for a pond area in many ways. Problem is it's low ground and I hit ground water that pooled in the bottom at only about 2 feet.

    I was just going to go 3 feet and about 10x10.

    I'm wondering what a pro's opinion on this would be. Should I dig as deep as I can and hope for the best? How much pooling water is too much (it's spring, so whatever I find now will likely be the most it will be).

    I'm in Ontario, so my concern is if the pond is too shallow my pond will freeze solid and the plants will die. Is this correct? Would it probably freeze solid at 3 feet anyway?

    I really don't want to move the pond as it's so perfect where it is...I guess I'm just looking for any experienced advice on how you would approach it.

    I can post pics if desired.

    Thanks folks.
  2. STL Ponds and Waterfalls

    STL Ponds and Waterfalls LawnSite Bronze Member
    Messages: 1,174

    Post a picture for better advice. A lot of people think a low spot is the best for a pond, but it can be the worst. You'll want to add a drain under the pond area to relieve any hydrostatic pressure that may happen in the spring with runoff. You'll also want to build a small berm around the pond to keep any runoff from entering the pond. Really just to keep any type of fertilizers etc from entering the pond. We can give better advice when we see the area.
  3. tadpole

    tadpole LawnSite Bronze Member
    Messages: 1,221

    Where exactly in Ontario are you located? There is another Forum member from the Brockville area that has encountered the same problems. Perhaps he will join in with his observations.
    Hydrostatic pressure can be a tricky problem to deal with at times. Photos of the site AND immediately surrounding area will definitely help as would more information such as the property elevation, proximity to wetlands, swamps and/or marshes, also a brief description of the topography of the immediate area and type of sub-soil at the 3 foot depth mark.
    As Keith pointed out, the lowest area of a property might be a likely location for an earth-bottom pond, but for a lined pond it is a potential nightmare.
  4. P.Services

    P.Services LawnSite Fanatic
    Messages: 6,319

    keep digging, go deep, open up the spring, let it flow and make a waterfall. Then it will never freeze. Heck with a stupid liner and filter system. You got lucky, dont work backwards now.

    now if its just stagnant water and not flowing, thats a different story.
  5. DragonflyGardening

    DragonflyGardening LawnSite Member
    Messages: 47

    Thanks a lot for the feedback guys. I took some pics last night but will take a few more and will upload and post.

    There is a serious "wet spot" about 200 feet away in the spring. A small stream and a flooded area 100'x40' or so - this dries up by mid summer. So where I'm looking at isn't the lowest spot around, but it's not too far from it and to the eye on about the same level. I guess I could have realized that, but you forget these things in the winter when you are picturing your beautiful pond :) We are new to the house too so still learning the ways of the land a bit.

    I hit clay by the time i get 2 feet down and then it's pretty much immediately a small amount of water seeping up.

    It sucks that this spot is such a low ground, it's perfect other than that. I can't really picture putting the pond anywhere else on teh property, but if this can't work I might.

    How would one go about creating a drain - is it essentially a hole, maybe with some o-pipe in it or something? Or a bit more complicated? How deep/wide would such a thing normally be?

    I'm near peterborough, on the cusp of the canadian shield.

    The pics will give a better idea of the topography and general shape than I can describe - it's a bit odd.
  6. DragonflyGardening

    DragonflyGardening LawnSite Member
    Messages: 47

    Interesting. It may well flow. About 200 feet away there is a "wet spot" that sort of seeps up into a small stream which turns into basically a pond. This dries up in summer though - takes a while but it basically does.

    Now, if I have water flowing 2 feet down....won't it always be 2 feet down. Lets say I go another foot and it's nice and full there, won't it look pretty strange having a pit with no water for the first 2.5 feet? Is there a way to make that work?
  7. crazymike

    crazymike LawnSite Senior Member
    from Ontario
    Messages: 452

    no, you need to find a spot with no ground water, build above the ground water, or reroute the ground water/hydrostatic release.

    Hole filled by ground water won't make for a pleasant pond
  8. DragonflyGardening

    DragonflyGardening LawnSite Member
    Messages: 47

    Here are some photos of the space (it's not landscaped at all, please ignore the mess :))





    Thanks again for your help/advice guys. It's gotten cold again here so lots of time to figure this out, it's really a summer long "when I have time" project.
  9. Darryl G

    Darryl G Inactive
    Messages: 9,500

    I find this kind of ironic...you want a pond and you find one just waiting to be unearthed and it's somehow a problem. Usually groundwater is what you're hoping for to create a pond. Does nature have no place in our world anymore?
  10. tadpole

    tadpole LawnSite Bronze Member
    Messages: 1,221


    From what can be seen in your photos, my suggested choice for location would be adjacent to what appears to be your deck. You will have the advantage of added elevation, convenient viewing and accessibility.

    And Darryl, natural, earthen bottoms ponds are practical only on a somewhat larger scale (1/3 acre and larger) and are not ideal for housing decorative fish such as Koi or Goldfish due to the fact that they are bottom-feeders and constantly keep the water cloudy with suspended material. With a decorative pond, it is quite easy to maintain good water clarity.

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