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Things to know when adding waterfalls to a fish pond

Pond waterfall, resized image
When designing a fish pond, many people like the idea of listening to the running water in the evenings as they are relaxing. The sound of the water can de-stress people after a hard days work so adding a suitable waterfall at one end of the fish pond is the ideal solution Not many people realize that adding the same waterfall is also beneficial to the running of the pond as it aids in the gaseous exchange by disturbing the water surface, this results in the oxygen levels being raised higher than a fish pond without a waterfall. You should always remember though that waterfalls are not always as efficient as designed fish pond aerators so if required run both side by side to keep the oxygen levels in the water high enough for the health of your livestock in the fish pond.

When designing you fish pond waterfall it pays to make it look as realistic as possible and make sure that it actually blends in with your fish pond and doesn’t just look an afterthought added on after the fish pond was completed. If you are using rocks to build up your waterfall, try to use the same sort of textured rocks that you have used for any paving slabs around the fish pond or if you have a raised pond you could even build the waterfall in the confines of brickwork around the outside of it and then have an array of rocks inside for the water to trickle over and back into the fish pond. Have a look at photographs of natural waterfalls and see how the rocks or terrain plays with the flowing water, this can give you ideas when you are placing rocks on the course of the waterfall so that the current is disturbed and gives you that natural feel.

Now this section may seem a bit obvious to most of us but when we get carried away with our designs, and we have all been guilty of this, it is very easy to plan our builds in a disproportionate scale i.e. we could build a fish pond that is large and finish up with a waterfall that is too small or vice versa. Plan your fish pond waterfall so that it looks realistic to the fish pond, you don’t need a major torrent of water flowing from it, a gentle trickle will suffice and this usually produces the most relaxing sound rather than water gushing everywhere. You will also need to remember that the higher the waterfall, the more powerful the water pump required to get the water to the top of the waterfall and the faster the water will flow through the waterfall course, a sloping waterfall with a steady flow is what you should be aiming for.

To create the elevation for the fish pond water fall you can use cinder blocks or bricks and these can easily be disguised by adding decorative rocks on the outside of the structure, you can even make pockets in the rocks and fill these with some of the topsoil from the fish pond excavation so that you have planting areas, alpine plants or similar look great in these small pockets. Bear in mind that a good water fall design will incorporate a small header pool at the top of the elevation so that a small pool of water collects once it has been pumped to the top before it is allowed to trickle down the waterfall course. Any pipe work from the water pump to the top of the elevation can also be hidden during the construction work so that everything looks neat and tidy.

There are three main materials that can be used for the waterfall course. The first is a self made concrete course, using this material allows you to be original in you design and rocks can be placed into the concrete while it is still wet to disperse the water flow, this will give you the soothing trickling noise plus once the concrete has set the rocks are firmly fixed in place. Remember to make sure that the sides of the course are high enough to prevent any water loss once the waterfall is flowing but a couple of inches of depth should cover this potential problem. The concrete will need sealing not only to prevent the water from being absorbed but also to prevent any toxins leaching into the fish pond. Pond paints are ideal for this but it will make the waterfall that little bit more expensive.

Off cuts of flexible pond liners can also be used for the waterfall course, this can be laid on top of the elevation and tucked in neatly at the sides. Smooth rocks can be placed below the fish pond liner to create small waterways inside the course and this is probably the cheapest method for completing the project.

On the market there are available preformed waterfalls that are constructed from durable PVC, exactly the same material as the actual preformed fish pond liners. They are moulded to look realistic and many will have little pools in their design that gradually fill as the water runs down the slope. Some of these kits may involve purchasing a separate header pool as well as the actual waterfall course and some kits include both parts that link together to make a complete run for the water. Header pools can be purchased separately if required and some designs even resemble small streams running into the fish pond.

Prices for these kits can range from £20-£30 but for ease of use and mounting I personally think that they are worth their price. Having a look around the internet will give you an insight into the many designs and sizes available choose one that blends in with the size and look of your own fish pond.

Selecting the correct water pump to supply you with the correct water flow can be a bit confusing, there are suppliers that can give you advice online if you do need help, it is better to ask than to purchase the wrong pump and then have to pay out for another one.

Waterfall pumps and fountains pumps work on the same principle, as there is a greater load on the water fall water pumps, these have to be more powerful but unfortunately with extra power comes extra running costs as they are usually rated at a higher wattage to do the job required of them.

When selecting your water pump you will have to take into account the width of the overflow back into the fish pond, narrower overflows require less power from the pump as the water flow will be quicker than with a wider overflow. If the overflow is divided into 2-3 smaller sections then the width of these will have to be added together to give you the total overflow.

The general rule is that water running over the overflow at 300 litres per inch of overflow gives a good speed for the waterfall, if your overflow is 12 inches wide then the required flow overall should be 3600 litres per hour. Increasing or decreasing the flow rate is simply a matter of highering or lowering the base calculation.

Another important aspect to consider is the height of the waterfall above the water surface of the fish pond, the higher it is the more power that is required from the water pump to get the water to the top. All of the water pumps are submersible but only measure from the water surface to the top of the waterfall. On the packaging and on some of the suppliers websites there is a curved graph displayed that shows you the relationship between the height and the water flow and how much it is affected so that you can read from the graph and know exactly which size water pump that you will need. If you are not sure then check with the suppliers and they will be able to help you and give you advice as to which water pump is most suitable for your needs. Your waterfall when completed will give your fish pond that extra touch and give you many relaxing evenings as the sound of the trickling water soothes you and your family!