There are two types of garden ponds – natural wild life and rigid plastic. When installing a pond, the first job is to decide on the location.
The fish in the pond need a mixture of sunshine and shade but care must be taken about the shade. Autumn leaves can decompose in the water if not scooped away regularly and this can lower the oxygen levels and eventually kill the fish. So the answer is to place the pool beside evergreen trees or provide cover for the fish by introducing suitable plants, like lilies, into the pond. If there are lots of trees in the vicinity, a cover net will stop the leaf drop and can also act as a deterrent from cats or herons stealing your fish!
To build a wild life pond, the outline should be marked out with a clothes line or hose pipe and the turf inside removed and stored for future use. The larger the pond the wider the variety of wildlife it will attract and a minimum size of between four and five square metres should be aimed for. The pool must be lined and the area of liner required is twice the maximum length plus one metre and the same calculation must be done for the width. The hole must be at least 750mm deep in parts to provide shelter when frozen over and the arisings from the digging can usually be deposited in a spare part of the garden.
The liner must be handled gently and if this means entering the pond area in the process of laying the liner, it must be barefoot order only! It is imperative that when the pond is filled with water the liner does not puncture as it is pressed into the excavated sides. This can be prevented by lining the hole with soft sand, a pond liner underlay or even blankets or old cardboard boxes. Pond liners with underlay can be purchased together, so you know the sizes will match! Water is very heavy and will press the liner very hard against the bottom and sides of the pond.
The liner should be held in temporary place around the pond edge by bricks or stones. The profile of the hole should include two or three platforms where plants can be seated in pots and should also have one edge sloping into the pool to provide a natural bird walk in washing area. The pond should then be filled with water – ordinary tap water will do at this stage – it can be treated to receive fish later.
As the water fills up the liner will slowly sink to match the profile of the excavation. The stones or bricks holding the liner at the edges must be moved to match the movement of the liner. When the pool is filled the liner should be cut back with about 500mm left projecting over the pond edge. The stored turf or paving flags should then be placed over the liner and the first stage of the pond installation is complete.
Installing a rigid pool is slightly more difficult because you have to make the profile of the excavation match that of the pool to keep the gaps between the two profiles to a minimum. The edge of the pond needs to be paved (or set in a small patio) and the irregular shapes between the straight edges of the flags and irregular shape of the pool edge should be filled with a weak concrete.
Finally, if the pool is set in a patio, make sure that the levels do not allow the waste from patio-cleaning operations to drain into the pool.