How to make a garden pond with a cascade?

A pond is a place of calm and makes a beautiful centrepiece to your garden. If you go one step further and add a cascade, you'll have the added joy of seeing and hearing the water as it flows! Besides, it has a practical benefit because circulating the water is essential for adequate oxygenation and hence preservation of the aquatic environment. It's a question of water quality and the health of your fish and plants.

On another level, installing a pond produces excess soil and stones from the excavation work. Using these materials to make a cascade feature is an efficient and economical solution.

Garden ponds

There are two common types of garden pond: prefabricated and built on a sheet. Of course it's also possible to build a masonry pond basin, but it requires a certain amount of technical know-how. Prefab basins have the advantage of being sold ready to install, but aren't well adapted to hard or stony ground. By comparison, the plastic sheet variety are able to adapt to any type of terrain.

Prefab basins

Prefabricated basins come in a range of sizes, shapes and internal volumes. They're generally made of polyethylene and ready to install immediately. Be careful if you have to contend with hard or stony ground, however, as these basins aren't really designed for that type of setting.

Installing a prefab basin is a relatively simple job. Choosing the right location is the key to success: neither too exposed to the sun, nor too close to large trees. Dimensions should be chosen according to the space you have to work with.

Plastic sheet basins

This type are much more flexible in terms of ground type. A PVC pond sheet with a thickness of 0.2 - 0.5mm offers the great advantage of being robust and flexible at the same time.

Again, installation is fairly simple; there are a few guidelines to follow to make sure you don't tear or puncture the sheet. The first thing to do is to scour the hole you've dug for any stones and then lay a geotextile sheet underneath before you put in the sheet.

It's also important to make sure you keep the sheet protected when putting up any features around the pond, either with any offcuts you might have or an additional sheet of geotextile.

Cascade features can also be prefabricated or built on a sheet. In either case you'll need to start with a mound of earth at one end of the pond basin with a drop of at least 20cm so that the water will be able to circulate.

You'll also need a submersible pump, which will drive the circulation of the water from intakes in the pond basin and out via the cascade. Before you start, make sure your pump  and cascade location are compatible: the distance and drop should be appropriate to the power of the pump.

Prefab cascade features

This type make a very convenient solution. Installation is easy, provided you pay careful attention to the manufacturer's recommendations. The most important thing is to check your levels with a spirit level to ensure that your cascade is installed on a perfectly flat surface. It's also important to tamp down the earth around the structure and put in plants such as grasses to bind the soil together with their roots.

Your submersible pump should be installed as far as possible from the mouth of the cascade, to make circulation as effective as possible. The pump pipe should be concealed under the soil right up to the cascade mouth, including the point where the pipe comes out, to make the whole thing look as natural as possible.

Plastic sheet cascades

The alternative is to build your own pond cascade. This can involve masonry work, but once again the easiest way is to start off with a plastic sheet. This should be laid on a perfectly flat surface about 20cm above the level of the pond.

It's a good idea to lay some stones on a geotextile sheet around the edge of the basin to underpin the whole structure, and fix them in place with mortar one you've checked the level with your spirit level.

The final step is to conceal the plastic sheet by laying more stones, pebbles or gravel; you can have several water outlets at different levels provided your pump is powerful enough.