garden pond

    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

 j wrote:

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.  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.

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. 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.  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.

David

 On 7/28/2011 6:35 PM, David Hare-Scott wrote:

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


  If you are

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!


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

Nope. I'm sold on drippers.

Then there is the

   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

 
Jeff, runoff water is a bad idea to my way of thinking. It will
contain all manner of contaminants.  We have kept Koi for 18 years and
even raised the pond halfway out of the ground to keep runoff water
out of it.  If it comes from the ground around the pond it will
contain fertilizers or weed killers and pesticides. Not knowing what
kind of roof you have, that may also contain remnants of the roofing
material, dead bugs, bird crap, and anything else that falls out of
the sky.
The raised sides from the soil taken out of the pond area is a great
idea.

Good Luck with your pond. Ours is 11 z 17' and has given us a lot of
pleasure over the years.
Nan in DE