Digging the pond: shelves, a liner and eleven barrowloads of clay

26 October 2024 · 3 min read

The spot was the only part of the lawn that gets sun for more than half the day and is not over the drains. I marked out an irregular oval with a hosepipe, roughly 2 metres by 1.5, and started digging on the Saturday morning of the 12th of October. The first 15 centimetres were topsoil and roots. Everything below that was heavy orange clay that stuck to the spade and had to be scraped off with a trowel every third cut. Eleven wheelbarrow loads came out in total over two weekends, and I stopped counting the blisters.

The profile I dug has a deep section of 60 centimetres at one end, about 70 centimetres across, so that there is water that will not freeze solid in a hard winter. Around that is a shelf at 25 centimetres for planting baskets, roughly 30 centimetres wide, and at the far end a long gentle slope up to the lawn which I have covered with pebbles as a beach, so that anything that falls in can walk out. The spirit level on a plank across the hole showed the rim was 4 centimetres out at one corner, which I corrected by building up with the spoil rather than digging deeper, and which I would still fix properly if I were doing it again.

Underlay first, an old carpet offcut and a layer of sand over the clay to protect the liner from the flints I kept finding, then the liner itself, a rubber sheet 4 by 3.5 metres, laid loosely and pleated into the corners. The trick that worked was to put 10 centimetres of water in before fitting the folds, so the weight pulls the liner into the shape and the creases can be tidied as it fills. The edge is tucked under the turf and weighted with flat stones.

Filling took three water butts and, I confess, an hour of hose for the last third. Total volume by my estimate is about 900 litres. On the 15th the water was cloudy with clay; by the 18th it had settled. And on the evening of the 18th, three days after filling and before a single plant had gone in, there was a water boatman rowing across the surface. I have no idea where it came from. I wrote it down, with the date, and that is how this list began.