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.
thefirstturf
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.
thenextbitofdigging
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.
threequartersdug
I did a couple of hours digging each time.
copy-of-dsc_0091
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.
levellingthesite1
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.
spiritlevel
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
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.
problemedges
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.
slopingtheedge
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.
reallyfinalshape1
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 proba
Here are my taddies congregating in the shallow warm water they love. This is right in the middle of my first pond: