Water flowing from a garden cascade will greatly increase the impact of your pond. A sloping garden is well-suited to a cascade, but you can have an effective one on a flat plot, too, as long as you keep the scheme low and wide so that it looks natural. Stones can be placed at the edges of each fall for a more attractive appearance and to protect the lining from the constant force of the water.
Cascades don’t have to look natural, though. Geometric formal pools, built above ground and connected by wide falls, can be striking and ideal for inclusion around entertaining areas.
Selecting the site
Choose the site for your cascade carefully. The water will have to be recirculated continuously, with only occasional topping up to compensate for evaporation. That means an electric pump. Pumps need power to run, but don’t let proximity be the overriding consideration. It is better that your cascade looks as if it belongs than to place it in an improbable place that is handy to a power supply. Set water features low down, for that is where water is normally found.
Each level of a stepped cascade should have a vertical drop of at least 150 mm, although a fall of up to a meter can be very effective.
But remember, the higher the lift, the smaller the volume of water a pump can handle. Flexible vinyl tubing can be used to transport water from the bottom to the top of the cascade.
What to get?
Two types of pumps are available – submersible and surface – but for most garden installations, submersibles are cheaper, easier to install, quieter and able to move a sufficient volume of water. Submersibles range in price depending on capacity. They must be supplied by an armored cable buried at least 600 mm below ground level.
Low-voltage models supplied by transformers are simpler to install and safer, but less powerful. In general, pumps cost little to run.
Prefabricated pools are priced according to size. For a garden cascade, you’ll need several purpose-made elements. Kits including the pump and piping are available.
A submersible pump with a transformer is the recommended choice, but as its name suggests, it must be fully submerged at all times. Choose one of a suitable capacity to lift the desired volume of water to the desired height – the supplier will be able to help you here. Place your pump so that the length of pipe between the upper and lower pools is as short as possible. Avoid placing the pump at the end of the pool opposite the cascade, as this creates currents that cloud and cool the water to the detriment of fish and some plants. If not using prefabricated pools, be sure to lay a sturdy pool liner. Concrete is not recommended, as it cracks easily, leading to leaks.