Digging pond - can I use spoil for banking?
 

Hi All

I'm currently digging a large wildlife pond (approx 30 feet by 20),
using an excavator. I've started by scraping a lot of the soil from the
middle to the sides, with the intention of getting rid of the soil
either elsewhere in the garden or into the skip. But it's occurred to
me that the growing mound around the pond is rather attractive, and if
used as part of the actual sides of the pond, would mean I wouldn't
have to dig so deep. In other words, if I dig out a foot of soil and
bank it up by a foot, then in effect I have a 2 foot pond, with the
level of the water above ground level. This would be very convenient as
I wouldn't have to get rid of so much soil.

Is there a problem with this idea? For instance, would the pressure of
the water push out the sides? Would the banking compact down in time,
leading to an overflow? Is it a bit odd to have the water level
somewhere round your knees? What could I do with the banking -
grass-seed it? Turf it? Would it make it hard to hide the liner?

As you can see, there are quite a few unknowns here. Has anyone done
this sort of thing?

Thank you very much in advance,

Will

Do you have a natural water course through the pond?

If so, the levels of this will control your destiny.

My daughter and son in law have a stream through their land and have made a
pond as you say, complete with an Island and a boat :-))

However if yours is 'made up land', you need to bear in mind the surrounding
land or 'leakage' will take place, unless you are sealing it with a secure
liner AND substantial banking to support the water.

Mike



wrote in message
oups.com...
Hi All

I'm currently digging a large wildlife pond (approx 30 feet by 20),
using an excavator. I've started by scraping a lot of the soil from the
middle to the sides, with the intention of getting rid of the soil
either elsewhere in the garden or into the skip. But it's occurred to
me that the growing mound around the pond is rather attractive, and if
used as part of the actual sides of the pond, would mean I wouldn't
have to dig so deep. In other words, if I dig out a foot of soil and
bank it up by a foot, then in effect I have a 2 foot pond, with the
level of the water above ground level. This would be very convenient as
I wouldn't have to get rid of so much soil.

Is there a problem with this idea? For instance, would the pressure of
the water push out the sides? Would the banking compact down in time,
leading to an overflow? Is it a bit odd to have the water level
somewhere round your knees? What could I do with the banking -
grass-seed it? Turf it? Would it make it hard to hide the liner?

As you can see, there are quite a few unknowns here. Has anyone done
this sort of thing?

Thank you very much in advance,

Will

Hi Mike

There is no water course - it's a self-contained pond. I am using a
butyl-like liner so I would hope there would be no leakage.

Will

wrote in message
ps.com...
Hi Mike

There is no water course - it's a self-contained pond. I am using a
butyl-like liner so I would hope there would be no leakage.

Will


Build your banks at least 1 metre deep, ie 'back' from the water and no
probs :-))

Mike

On 18 Sep 2005 09:18:26 -0700, wrote:

Hi All

I'm currently digging a large wildlife pond (approx 30 feet by 20),
using an excavator. I've started by scraping a lot of the soil from the
middle to the sides, with the intention of getting rid of the soil
either elsewhere in the garden or into the skip. But it's occurred to
me that the growing mound around the pond is rather attractive, and if
used as part of the actual sides of the pond, would mean I wouldn't
have to dig so deep. In other words, if I dig out a foot of soil and
bank it up by a foot, then in effect I have a 2 foot pond, with the
level of the water above ground level. This would be very convenient as
I wouldn't have to get rid of so much soil.

Is there a problem with this idea? For instance, would the pressure of
the water push out the sides? Would the banking compact down in time,
leading to an overflow? Is it a bit odd to have the water level
somewhere round your knees? What could I do with the banking -
grass-seed it? Turf it? Would it make it hard to hide the liner?

As you can see, there are quite a few unknowns here. Has anyone done
this sort of thing?

Thank you very much in advance,

Will

I'm planning much the same thing and am following your various
questions with interest! My site slopes very slightly, so the uphill
edge will be cut down and the lower edge will be banked. I intend to
give the banking a core of stone, rubble, old concrete etc. to give it
weight and strength, and cover it with soil which I will compact well
to reduce settlement. The lower part will in fact be a bog garden
connected to the pond.

I have a Titchmarsh video on how to make a pond (IIRC recorded from
his TV series 'How to be a Gardener'). In it he runs his liner up to
the top of the edges/banks and pegs it at regular intervals with tent
peg type things (_after_ filling it with water). He then uses turves
to cover the edge and hold it down, with the lower edge of the turf
strip actually just in the water. The key point is that the edge of
the strip of liner shouldn't be too far up above the water level, say
about 6 or 8 inches at most. In this way, the bit of turf on top of
the liner draws its moisture from the pond itself, while the bit of
turf further up is in contact with the underlying soil and gets its
moisture in the normal way. Too wide a strip of liner would mean that
a bit of the turf between the ends mightn't get moisture from either
direction.

I'm not yet sure how I will do my edges. A problem I foresee with
Titch's method is when it comes to cutting the edge. Obviously one
can't use a mower, and a strimmer will put all the strimmings into the
water. I will probably use concrete slabs for the upper part where the
edge will be on solid ground (I have a surplus that I'm keen to use
up), and rough stone for the lower part on the bank and surrounding
the bog garden.

However, it's still only at the planning stage, so I'll be interested
to see other people's comments.


--
Chris

E-mail: christopher[dot]hogg[at]virgin[dot]net

The message .com
from contains these words:

/snip/

As you can see, there are quite a few unknowns here. Has anyone done
this sort of thing?

No, but I was planning on doing something similar when I had a smallholding.

Since you're using a digger there shouldn't be a problem, as you can
strip the topsoil away and use subsoil for the banking, and you can
compact it with the digger's bucket in layers as you go along.

If you are going to stock it with fish, you may need to terrace the
bottom, as some fish like deep water, while others are hapy in the
shallows. But be wary of herons!

The topsoil, or some of it, can be used to cover the bank once it's
finished. To get a realistic look, I'd consider taking the liner to the
top of the bank before you put the topsoil on, and after securing the
edge of the liner, covering a foot or three with sand and/or gravel,
then the topsoil, and let the water come right up to the edge.

Using ASCII-art it's not easy to show slight gradients, but where the
liner ends should rise ever so slightly towards the edge.


......
.·" "·..
¯¯¯¯¯¯¯\______________
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\_____/

--
Rusty
Emus to: horrid dot squeak snailything zetnet point co full-stop uk
http://www.users.zetnet.co.uk/hi-fi/

Interesting comments - thank you. I'm still trying to resolve pptential
difficulties.

One problem is that the existing bank isn't well compacted. I've just
dragged the soil outwards so far. I think I may have to remodel the
bank, trying to compact it as I go, otherwise it will be difficult to
tend to the plants around the edges.

One other problem that I'm struggling with a bit is the planned shore
section. A wildlife pond has to have a gentle incline, and I'm not sure
how easy this will be to achieve with banked sides.

And the edging? As has been mentioned, grass will be difficult to mow,
but I'm struggling to imagine how I could use my original preferred
edging - some sort of paving or gravel - with a banked pond. I suppose
with a wildlife pond it would be more than acceptable to allow the
grass to grow long immediately round the edge.

Hmm. The convenience of not having to shift the soil or dig too far
down are still making the idea appealing, but I need to resolve some of
these things. Looks like the pond project might stretch forward for
quite a while yet....

The message .com
from contains these words:

/snip/

Hmm. The convenience of not having to shift the soil or dig too far
down are still making the idea appealing, but I need to resolve some of
these things. Looks like the pond project might stretch forward for
quite a while yet....

Especially if you use a butyl rubber liner on uncompacted soil...

--
Rusty
Emus to: horrid dot squeak snailything zetnet point co full-stop uk
http://www.users.zetnet.co.uk/hi-fi/

It's compacted underneath where the lining will be of course, but at
the moment, not around the sides, no.

Will

wrote in message
ps.com...
Hi Mike

There is no water course - it's a self-contained pond. I am using a
butyl-like liner so I would hope there would be no leakage.

Will

Banking will be fine if broad enough.
For edging it is important to get it right and you need to mark out the
level very carefully, I have found a long length of clear plastic tube
containing water with a few spots of food dye very useful for larger more
natural style ponds, using pegs. To hide the edge of a lined pond
successfully the liner must go under then up the back of what ever edging
you choose (not just under as that will leave liner showing whenever the
level falls a couple of inches) you want the water level to be about half
way up the edging, also bear in mind that some sort of beach or sloping exit
may be advantageous.

--
Charlie, gardening in Cornwall.
http://www.roselandhouse.co.uk
Holders of National Plant Collection of Clematis viticella (cvs)

Hmm. It took 15 hours for that message to appear!

Anyway, I'm beginning to have reservations about this idea. I'm
concerned about compacting the soil, and tending to the marginal plants
if I have a bank.

Has anyone actually done this (used banking to raise the level), and
managed to incorporate a successful 'shore' to make a wildlife pond?

Cheers

Will