Raised Ponds – their benefits and design

A raised pond is simply a pond that has been raised above ground level. They have become increasingly popular as gardens have become smaller and concerns over child safety have increased.

Wildlife ponds are also a great, if less obvious choice, for building a raised pond. They are frequently included in any aquaponic system where fish and plants are grown together. Such systems require careful control of water levels as flow rates between the fish tank and the grow beds need to be optimised. Having a raised fish tank does allow water to gravitate through the grow beds before running into a pump tank.

Top 5 Key Features of Raised Ponds

1.Child Safety

Every year far too many children tragically drown in garden ponds. Quite rightly safety should be at the top of everybodies list. A raised pond provides a vertical barrier to children and helps prevent naturally inquisitive toddlers from falling into the water. A raised pond will also have a definitive edge to which a strong mesh can easily be attached. This makes it virtually impossible for any child to get into difficulties without curtailing their excitement when feeding and touching the fish.

2. Easy to Build

Raised ponds make wonderful pond kits. These are usually quick and easy to assemble with little or no digging involved. Delivery is easily arranged using standard transport systems ensuring excellent availability throughout the UK at reasonable cost.

3. Easy to Manage Fish and Plants

One of the biggest advantages of a raised pond stems from the fact that it has a naturally elevated water level. This means that it can be drained easily without the need of a pump. A simple syphon is a very cheap and effective method of removing the waste that tends to accumulate at the bottom of every pond. This helps ensure optimum water quality, the key for maintaining healthy fish and plants.

Pond plants tend to grow very rapidly over quite a short season. They invariably require some attention if they are not to outgrow a pond and cause subsequent water quality problems. Excessive growth needs cutting back and dead flowers and leaves should be removed. This is greatly facilitated by the raised water level meaning that heavy plant baskets can easily be removed without bending.

small girl feeding goldfish in a pond
Feeding fish correctly is critical but child’s play.

Raised fish ponds allow regular and close contact with the fish especially at feeding times. An enthusiastic response to feeding indicates that all is well and water quality is likely to be good. If there are any underlying problems in a pond one of the first indicators is a reduction in feeding activity.

4.Timber construction possible

Moisture is the enemy of wood and must be controlled if rot is to be prevented. This is best achieved through natural ventilation that is only possible with a raised pond. Timber is a wonderful choice of material for a pond provided it is not allowed to get saturated. Modern pond liners are a cheap, quick and effective method of keeping the water where it should be. Wood acts only as a support and does not come into direct contact with any water. Toxic chemicals can easily leach out of a concrete, or even glass fibre pond, if proper precautions are not rigorously followed. Timber is easily cut, drilled and shaped and, as such, make excellent pond kits. Essential filtration systems and other accessories are easily connected through the side the pond. Fish ponds, in particular, really do benefit from a good filtration system if reasonable numbers of fish are to thrive.

5.Cost effective

For most of us, price is always an important consideration when decided upon the best pond to install. Raised garden ponds are not the cheapest method of installing a pond but they are often the best solution and represent excellent value for money. There is little digging involved so no need to dispose of excess soil. It’s always surprising just how much soil comes out of a hole and hiring skips is not a cheap option! Due to the fact that they are easy to assemble it is also usually possible to move raised ponds around the garden to fit in with evolving changes in garden use and design. It is even possible to sell or recycle the pond if it becomes no longer required. Most other ponds would require considerable effort, not to mention expense, to remove them. Bigger and better filtration systems are a frequent aspiration of many pond keepers so it is sensible to keep back some budget for future developments. An old pond can often be given a useful second life as a breeding or quarantine system, so invest wisely.

How to Build a Raised Wooden Pond

Design parameters – depth

One important thing to bear in mind is that timber is primarily used for small garden ponds that are normally less than one metre in depth. It is perfectly possible to go deeper but the stresses involved increase dramatically and as a result additional reinforcement and strengthening will be required. Generally I would recommend depths of less than 80 cm. This is not normally a problem. I have grown carp to 36lbs., catfish to 20lbs, and grass carp to a British Record 26lbs in such shallow ponds that have been no more than 8 feet in diameter. Contrary to popular belief fish grow to a size determined by the water quality and not the physical size of the pond. Shallow ponds greatly facilitate viewing of any fish and subsequent netting when required. Fish lurking in the murky depths are susceptible to unseen parasites and disease.

Concerns over water temperature fluctuations have been raised in the past about raised ponds. This is best addressed by incorporating a layer of insulation. Closed cell styrofoam is a popular choice. For an unheated pond I would suggest a 2inch layer. If heating is likely to be employed then this could usefully be increased to 4 inches. This opens up the very real possibility of heating a pond along with all the advantages that this offers.

Optimal Shape

Pond shape plays a pivotal role in their performance. Twisting, convoluting shapes may look good on paper but in practice they trap loads of fish waste that will invariably cause problems some time in the future. Round tanks are virtually self cleaning if a central bottom drain is incorporated and are very popular in aquaculture. Flow rates can be adjusted easily by angling the inlet. They are not always the best choice however. I would always advocate that an air pump is used to provide a secondary supply of oxygen in the event of pump failure. It is a risk if the water inlet is the only source of oxygen. Carefully placed inlets will alter the flow patterns and affect self-cleaning abilities. Fish are also more difficult to capture in a round pond. A rectangular tank allows fish to be easily graded and segregated if required. Overall I would recommenced this shape for small, rapidly growing fish. If you still like the self-cleaning abilities of. They do not even need to be netted a round pound but would like to build it in timber it is well worth considering a hexagonal pond. Once the angles have all be calculated they are no more difficult to build, offer excellent flow patterns and provide excellent water volumes to size ratios. In other words you get maximum pond gallonage for the cost.

Sloping Bottoms aid maintenance.

Wooden ponds made from log cabin type materials have become very popular over recent years. They are quick and easy to install using interlocking planks. The price of these logs can be high as they need to be a minimum thickness to avoid excessive bowing. I prefer to use sheet material and OSB3 it my material of choice. It is relative stiff, cheap and has a resistance to damp that is superior to plywood. Panels are fixed to a sawn timber framework that provides strength and rigidity. The framework also means that insulation panel are easy to incorporate. The

Construction Method Guidelines.

My construction method can be likened to an inside out boat build. First stage is to construct a number of supporting frames or ribs. These use strong 45 degree braces, secured with bolts, that prevent bowing and allow the installation of a sloping bottom. As several of these ribs are required construction can be speeded using a simple jig. The angled braces are secured initially with screws but subsequently with bolts that run through the entire brace.

Sloping pond bottoms are a really beneficial feature that concentrates the fish waste in a central band running down the deepest part of the pond. Consequently, syphoning of waste is a simple affair that can be achieved in just a few minutes. It also helps to concentrate the waste at the pond outlet that is sucked off the bottom of the deepest part of the pond prior to entry to the filtration system.

The ribs are attached to the bottom stem, or keel, at regular centres of around 400mm. Plastic pedestal supports can be attached to the base of the ribs at this stage.As well as providing a really easy method of levelling the pond they all serve to keep the timber framework off the ground and prevent rot. Easy pedestal is capable of supporting over 500kg so there is no fear of any collapse.

The end panels are attached at the same time.

What’s available to buy

If you want to avoid building a raised pond yourself. This hexagonal wooden pond is well-worth a look.

Share this post

Share on facebook
Share on twitter
Share on print
Share on email