Creating Water Garden Features
There is no doubt that one of the most fascinating features which can be constructed in a garden is one which involves the use of water. Water has its own particular charm and there is a considerable therapeutic effect when one sits beside a pool and watches the antics of the fish or the movement of the water created by a fountain or waterfall.
Little artistry or constructional skill is needed in order to complete a very natural-looking effect. This is mainly due to the versatile range of accessories at the gardener’s disposal. The simplest feature is a pool which can be of formal design or informal. The former is either rectangular or square with straight sides or edges. It can be incorporated in many garden schemes and is particularly useful in a terrace or lawn setting. The informal design has an irregular outline and lends itself to the inclusion of other natural features such as a waterfall or stream which is designed to tumble into it. It is important, therefore, to decide at the outset, which type of pool is to be constructed.
Two ways in which a pool can be built are by using prefabricated pools or by using plastic liners. The costliest is by the use of prefabricated units which are moulded in plastic or glass-fibre. Both formal and informal types are available in the larger sizes, but the latter are available in large numbers and in all shapes and sizes.
Installation is quite straightforward as all that is necessary is for a hole to be excavated just larger than the unit and, after stones have been removed, some of the excavatedis used for backfilling when the unit is in place. Care must be taken to see that there are no large areas of unsupported unit which could be damaged or distorted when the water is added. Water is very heavy!
Plastic liner pools are very successful and if the tougher grades of plastic are used, many years of maintenance and replacement-free service should be provided. Some of these liners are coloured —usually a pleasant blue, about 6 in. at the sides and ends for the overlaps:
Where ledges or shelves are required in the pool to provide different depths of water for the variousthese must be allowed for as extra measurements. Usually one shelf is adequate all round the sides, about 9 — 10 in. below the surface of the water. To avoid the necessity for shelves, plant containers can be raised on bricks.
Particular care should be exercised when the excavation for a liner pool is being undertaken, and all stones etc. must be removed to prevent damage to the liner. The base of the site should be lined with about 1 in. of sand which will serve as a cushion for the liner. The edges of the liner in a formal pool can be concealed very attractively if a row of paving slabs is laid all round. In an informal pool, crazy paving could be used or the edge of the plastic can be hidden or trapped by grass turves. The installation of a liner can be facilitated if, when it is in its approximate position, a little water is allowed to run into it. The weight of this water will pull and press while others are reinforced with nylon. One of the toughest and most durable of the liners is Butyl, a rubber-based material of exceptional strength. As it is black in colour it looks more natural than the coloured liners.
None of the plastic or rubber-based liners is easy to use in formal pools if the contours of the pool are complex and to reduce the number of necessary folds and creases when the material is laid over the undulations, the number of contours should be kept to the minimum and should also be as gentle as possible.
A formal pool is quite easy to make from a liner and a careful fold at the corners will be all that is necessary to maintain a reasonably crease-free surface all round the pool.
For all liners, an overlap of material must be allowed for so that it can be taken over the edges of the pool by about 6 in. Material for a pool can be calculated on the basis of length (overall length of the pool, plus twice the maximum depth); width (overall width of the pool, plus twice the maximum depth). Allow the plastic in place and it is a very useful method when an informal pool is being made. The edges of the liner can be retained by several pieces of stone as the water is run in.
Features such as a waterfall can be installed very quickly if a prefabricated unit is used. These are finished in a simulated rock face with little rocks protruding in the `run’ to break up the water flow effectively. Several units can be linked to form a series of cascades. A stream course can also be introduced easily by the use of preformed units. Several can be arranged to form an intriguing course which could empty into a waterfall basin, which in turn finally empties into the main pool itself.
The movement of water from the pool to the top of a waterfall or stream course is provided by an electric pump. There are two types, a surface pump which is installed outside the pool with a suction pipe connected to it and into the pool water. The submerged designs of pump (w) require less installation work as they are simply placed in the pool water. Several are connected to a transformer which reduces mains voltage to a safe 24 volts or so.
By means of extra piping and gate valves, a powerful surface pump can be used to provide a fountain effect and a waterfall at the same time.
The submerged pumps can operate a fountain and a waterfall simultaneously by means of an adaptor which is often supplied with the pump. For spectacular water effects it is necessary to select the more powerful electric pump.
Another most effective way of making a water feature in the garden is to construct a raised pool. This can easily be incorporated ideally in a terrace or patio feature. It is an excellent design for the elderly or infirm gardener because it reduces the need for stooping while the pool is being attended to.
Construction involves a little more work, but it is well worth the effort. The height of the pool above ground level is a matter for personal decision, but generally a height of about I to 4 ft. is adequate. It is necessary to build an inner wall first, using breeze blocks or concrete blocks. This is the retaining wall which supports the liner and water. A firm footing or base of concrete should be provided in a 2 in. deep trench.
An outer wall is then built up about 3 in. distant from the retaining wall. For this wall, the decorative or rough textured walling stone is ideal. Again, a good foundation is essential for this wall. The tops of the two walls must, of course, be level. When set, the hollow between the two walls can be filled in with some of the excavated soil.
A plastic or, preferably, a Butyl liner, cut to size can then be used as a waterproof liner inside the retaining wall and the edges laid on top of the breeze or concrete retaining wall. To finish off the feature, suitable broad capping stones can be laid along the top of the walls and cemented in place. These capping stones also trap and retain the liner. Before this, partly fill the pool with water so that the liner is pulled into place and as many folds and wrinkles as possible are smoothed out.