On 7/28/2011 6:35 PM, David Hare-Scott wrote:
j wrote:
I've acquired a 12' x 18' epdm pond liner. I can fit about 2/3 of
that in. It's mostly shady where it will go.

I've never had a pond of any size. Water is getting expensive here
and I wonder if I can fill this with runoff and use it to water my
modest garden. We get about 4"/month. With somewhere between 500
(easy) and 1000 (harder) SF (horizontal) of roof to help feed it.

Any ideas on depths and what to put in it? Caveats? It looks to me
that it will be marginal being able to withdraw water and it will be
hard enough to fill if it is deeper than a foot, but I have no
experience to back that up.

Jeff

To store a decent amount of water you will need a big hole. By 'big' I
am thinking at least 10 kl (12 cubic yards) or bigger.

Oh, that will be tough for where it goes. I think 2/3 of that I can do.


If you are
thinking of only a fraction of that you will be going to much trouble
for little return. Do some sums and work out how much water it will take
to give your garden beds 1" of rain. You seem to have picked a spot
already so how deep could the hole be there? What's the soil like? You
are not going to dig that by hand on Sunday afternnoon. Either you will
be digging for a week or hiring equipment.

I think I'll give up on the water storage. Digging the smaller hole is
doable for me. I'm about half way there by using the dirt in the hole to
form a levee around the edge, if you will. I'll make this a design
feature instead. Just what I needed, another impractical project!


For easy filling the hole needs to be close to and below the collection
roof, plastic drainpipe about 90mm (3 1/2 in) will get there.

I'm OK there as the pond is next to the house. I have another 350 SF of
roof I can drain off I overlooked.

It needs
to have an overflow to a convenient drain of some kind. A pump and
piping will reticulate it to your garden. If you were thinking of
watering with a bucket you will get very fit indeed.

Nope. I'm sold on drippers.

Then there is the
possibility of children, dogs, drunks drowning in it or the pond failing
local pool ordinances if it is unfenced. The liner is only part of the
cost. Plan well before you dig.

I have a friend that just put in a large pond (day with a bobcat).
Probably around 24 cubic yards. He has no garden though. And is awash in
water as it is as he has a good size stream running through his
property. His only goal at the moment is bees.

Thanks.

Jeff

David