How to build a wildlife pond or conservation style pond: the easiest technique for a pond in relatively flat and stable ground

When things are nice and simple, and the ground is firm and flat, the easiest way put in a flexible liner is the standard conservationist technique and is only suitable for informal water gardens. This little article could easily have a heading:

How to Build Ponds in the 'Continental Fashion'

The reason this method is so popular is because it doesn't involve any construction at all. All you need is a good strong spade and back for digging, some pegs (longer than the intended depth of the pond), the corect amount of liner and underlay and a good quantity of soft heavy sand (Holme sand).

The Method

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Take a sturdy peg longer than the depth required for your pool. Mark the depth on the peg and drive it into the ground to the expected water level. Excavate to the level marked on the peg. This is your datum peg, so ensure it remains undisturbed.

This method allows for a shallow entry for wildlife, a stable anchor for the liner and a bit of irregularity at the edgeUsing your datum peg level, cut a V shaped trench, around the inside of the proposed shape of the pool. The inside edge of this V needs to be no more than 5cm below the level of theThe pool excavation lined, the marginal area filled with heavy sand and now nearly filled with water: Underlay goes in first then the butyl/epdm liner on top of that and then another layer of underlay. I would advise that the last layer of underlay does not come above water level to prevent any 'wick' effect. datum peg. The depth of the V needs to be just over 25cm deep. The outside edge has to be consistently above that level and needs to slope gently away from the pool.

The excavation should gently slope down at 30 from the V to the required depth.

Consolidate the hole by tamping the soil and remove sharp stones. Line with soft sand and a protective underlay material before laying the rubber or plastic liner material.

If you are completely committed to the natural look then drape underlay in strips on top of the liner. After that sub-soil can be used to be laid on top of liner. Nowadays though, it is thought that in order not to burden future cleanouts with tons of inseparable mud, the underlay it is best left to accumulate sediment and detritus through the normal activity and development of the water garden eco-system. Live with bacteria, the underlay soon becomes obscured under sediment that is unless the underlay floats to the surface in the meantime.

Open out the liner in the hole and fold into place. Collect as many of the creases up together as possible into one fold. don't let the water stretch it into place. Life just aint that simple.

Ensure this underlay does not emerge from the V and go on to end up lower than the water level, otherwise it will end up as a wick capable of siphoning the pool dry.

The V can be filled with soil and planted. It can work as sort of hod or cradle for pebbles creating a beach effect or it can contain the concrete footing for an upright timber edging.