Few sounds are as relaxing as the gentle splash of running water – and for many of us the thought of being able to enjoy that alone is one of the main reasons for wanting a pond in the first place. A waterfall looks particularly effective for an informal or wildlife pond – as well as helping to keep the water oxygenated – and with a bit of careful planning, making one is not particularly difficult to do.
The waterfall itself can be as simple or as complicated as you wish to make it, even to the extent of having an artificial stream with several mini-waterfalls along the way. Whatever the design, the idea is very straightforward – water is pumped from the pond up to a smaller collecting pool and then flows back into the pond. There are two main ways to create the main part of the feature, either using one of the pre-formed waterfalls available – which can be linked together to create a cascade – or a flexible liner. For a cascade effect, deciding between them really comes down to personal choice, but for anyone looking to install a simple waterfall fairly quickly and with the minimum of fuss, the pre-formed mouldings are hard to beat. Although concrete can also be used, the need to seal and waterproof it to stop chemicals leaching out into the water generally makes it less convenient.
To give the water the height it needs to flow back properly, some earth works are probably going to be needed – an excellent use for the soil dug out when the original pond was excavated. Many pond builders combine this with a rockery, which tends to make the waterfall itself fit in better. Whether you are going for natural-looking cascades flowing at different angles or more of a curtain of water, the next job is to work out the rough form of the waterfall. At this stage, the hosepipe that will carry the water from the pump up to the top of the fall should be buried – making sure to leave a bit of extra length just in case – and the soil firmed down well to avoid it dropping later.
If pre-formed units are being used, you need to work out how they are going to fit together and shape their resting places accordingly. With a liner, you have a blank canvas, but need to pay more attention to forming the actual “bowls” if the feature is to run properly. If you are creating a series of cascading pools with a liner, they should slope backwards slightly to make sure that they fill up properly and stop any stones used to decorate the waterfall from simply getting washed all the way down and into the pond. It also helps to make the whole thing look more natural. Pre-formed or liner built, remember to plan to have the final lip overhanging the pond by five or ten centimetres to get a good splash.
With the earthworks ready, the actual installation is very much like putting in the original pond – checking that everything is level and remembering a protective layer in the case of a liner or making sure that the moulding is properly supported. To be on the safe side, some pond builders like to cement pre-formed pools in place.
Once everything is ready, the hose pipe connected and the pump switched on, if the result is not quite what you were expecting, all is not lost. Different arrangements of stones in the waterfall pools – especially near the lip – can change the way the water flows, so it is worth experimenting a bit to find an effect that works for you. However, if the Niagara look-alike of your imagination is more like a trickling hosepipe in reality, your pump is probably too small – or its filter is blocked – but the good news is, both are easy enough to remedy!
Sizing the pump is one part of pond-keeping that is often overlooked, at least until it becomes a problem. As a general guide, for every one centimetre width of waterfall, you need a pump capable of delivering around 150 litres of water per hour – perhaps up to 200 litres per hour if you really do want to rival Niagara! On this basis, a 3000 litre per hour pump, for instance, would be fine to feed a 20cm wide waterfall.
At its best, water gardening, like all gardening, involves a bit of effort at the time to be rewarded by a lot of pleasure later and giving your garden pond a waterfall is probably one of the best examples of this. There really is nothing quite like sitting out on a sunny day beside running water – and with a spot of creative lighting, your waterfall can become a dramatic evening feature too.