The new pond, finished on 26 April 2009: now I'm just waiting for the rain to finish filling it
This is the full story, in pictures, of the making of my new wildlife garden pond.
I’ve tried to bring together a design which takes account of the many myths that exist about ponds and which have come to dominate garden pond design.
What makes a good wildlife pond is:
- really clean water: this is the most important thing you can do for a wildlife pond.
- plenty of shallow areas: and shallow means less than 5 cm.
- edges as natural as possible: in a garden in practice this means grassy, very gently shelving, and gently varying in depth.
Most advice about garden ponds barely mentions these things. The reason: almost nothing is known about what really makes garden ponds tick. So writers, who abhor an intellectual vacuum, simply make stuff up! Amazingly.
The advice here is based on Pond Conservation’s work on ponds out in the countryside – but even we don’t yet know much about real garden ponds. But we’re learning fast, and the advice below is putting what we do know into practice.
UPDATE: As the pond develops I’ll also be trying to make it look as attractive as possible as well.
Anyway, back to the beginning: the 1st of March 2009 to be exact.
The first cut. I marked the site out with a rope. You can use a hosepipe, string between sticks, bamboo canes – whatever suits you.
For wildlife, the pond shape is less important than the depth (you need lots of shallow water) and the how clean the water is, and what the edges are like.
So ‘natural or ‘formal’: it depends on what looks good in your garden.
Remove the turves: you won’t be needing them again. Don’t put them in the pond! They will almost certainly add a massive blast of polluting nutrients to the water which will plague you for the rest of the pond’s life.
It doesn’t matter when you start or when you finish. I started in March because I had the time then – too late for breeding frogs this year but in time for the main period of warm weather when all kinds of bugs, beetles, mayflies, dragonflies and all the other things are flying about to colonise the pond.
I did a couple of hours digging each time.
By the 11th April I had all the turves stripped off. This took me about 6 hours all together – its slower if you don’t do it all at once. Probably I could have got this far in a long afternoon.
I was fairly confident that the site was more or less level – now it was time to check more carefully.
I needed a piece of wood more than 3 m long to go right across the pond. I didn’t have one at home so had to buy a piece from the local timber merchants for a fiver. I expect you could scrounge something like this for free.
With the spirit level laid on the wood, I could see that the pond was a little bit higher at the back, the side away from the camera.
It wasn’t too much but did mean a bit of fine tuning was needed at the end.
The bubble should be between the two lines
Its very easy to dig a wildlife pond too deep and end up with one of those things that looks a like a miniature version of a giant open cast mine.
A wildlife pond should have lots of shallow water – mine is roughly 50% shallows, and the deep area is not more than 30 cm.
The standard advice that you need to dig down to 50 cm or 60 cm of whatever the writer thinks applies only to fish ponds. The reason you’re told to do this – the pond might freeze solid – might apply in northern Canada, but is simple nonsense in England. The other reason – that oxygen may run out – is probably true sometimes but is not a cast iron rule.
Those of you who read the blog will know that in my first shallow pond oxygen levels rose during the ice cover this winter to double the normal value.
The other problem with digging down this deep in a small pond is that you end up with very steep, or vertical, edges. I’ve managed to get away with having only one ‘cliff’, between the shallow basin and the deep area.
The maximum depth is not much more than 1 spade deep
Update 2 May 2009. Just saw this comment on a wildlife pond making website:
‘To assist with water clarity, make your pond as big as possible and avoid a deeply shaded site‘.
There’s no reason to think that either the size or the amount of shade will have anything to do with how clear the water is.
In fact, shaded ponds ae more likely to be clear (less light for algal growth); size really makes no difference.
Anyway, getting back to story, at this point I realised I had a big problem with the edges.
Just in the simple act of removing the turves I’d created a massive steep cliff right at the edge of the pond: the place I was trying to get the gentlest slope.
This happened because its very difficult to dig a turf out that isn’t this 4″ (10 cm) deep because its where the grass roots down to.
There are probably a variety of solutions to this problem.
I chose to raise the turf, remove roughly half the soil from each turf making it half the thickness, and place the spare soil in from the of the turf so making the slope from pond to grass a bit gentler. I don’t think its the ideal solution but it was fairly quick to do.
Now the pond bottom will be at the same level as the bottom of the turf at the edge of the pond.
But the real way to get shallow water in a small pond is have shallow basins.
So this is the final shape: in large parts of the pond, it hardly looks as though I’ve done any digging at all. This is the right depth for pond wildlife.
Tadpoles love shallows: its where they spend a lot of time in my first pond.
Here are my taddies congregating in the shallow warm water they love. This is right in the middle of my first pond: normally the deepest area, in my pond its the exact opposite way round. The middle of the pond is the shallowest area, so shallow it will dry out in the warmer weather. But now its great for the baby frogs, and by the time it dries, they'll probably have grown up and left the pond
Almost all other pond wildlife is happiest in very shallow water as well.
Most garden ponds are too deep for their area: if you want a half metre deep pond, or deeper, it needs to be much bigger or you end up with very steep sides.
The really final shape with turves cut and arranged to cover the liner
The really striking thing about the final shape is just how shallow the pond is: I’m pretty pleased with this, although there’s room for improvement around the edges.
Now the lining: I opted to buy the underlay just for speed – I didn’t have any old carpet around so simply put down a double thick layer of the underlay on sale at the garden centre.
I did remove the stones fairly carefully, but I didn’t bother with sand.
As the total bill for liner and underlay was £134, and as I will have hours of pleasure from the pond for nothing apart from this, I didn’t mind the expense. The liner itself was £90.30. But the resourceful could do it for less.
This is the same approach as I took on the first pond (except there I had a left over roll of underlay I could use from the previous owners of the house).
And then suddenly we’re nearly done: put the liner over the top and add some water to hold it down.
Notice – no hoses. My tapwater is not fit to use in a pond – full of nutrients. In some parts of the country (in the north, for example) its OK where its come off the moors. Down south, its mostly not fit to use in a pond. In most parts of England you can check on the water companies website whether your drinking water is fit to go in a pond – in about half the country it isn’t.
From here on in we have a pond!
Now you begin to see the two halves of the pond.
Now it’s just a case of finishing putting the turves in place, and trimming the liner and underlay.
I didn’t quite have enough water in my water butts to fill the pond completely so now we need to pray for rain – luckily it came the next day.
Everything trimmed up, and the turves all in place. There’s even the first leaves falling in the pond: leaves are a great source of food, shelter and building materials for pond animals.
And finally:
Two months almost to the day (this picture was taken on 27 April 2009) the pond is finished and ready for wildlife to find it.
Its still not quite full: the next day the rain came.
What’s next?
Well, we will add some plants to this pond: local, native, wild sourced plants (only collected from landowners who’ve given permission).
We won’t add ‘pond sludge’: the pond doesn’t need to be ‘started’. We’ve started it simply by making the hole and filling it with clean water, and anyway that sludge is quite likely a source of nutrients from someone elses pond that we don’t need.
We don’t want soil, or turves or fish food or any other of the pollution sources that commonly find their way into ponds. We will have more than enough just coming down in the rain (rain itself is slightly polluted these days).
We will put some clean children’s play sand on the bottom to make the pond a little more natural looking. This is chemically inert so no pollution problems, provided its clean.
And the wildlife? Well that started to arrive on day 1 with little flies laying their eggs, and on day 2 the first water beetles flew in.
