Garden ponds

One of nature's most valuable commodities for wildlife is water, and no indigenous garden that is planned to attract wildlife is complete without it, even in its most basic form. Apart from the numerous bird species which naturally occur on water, such as the waders, and those that use the reeds for nesting, most birds and other small wildlife rely on water for drinking and bathing, a need for which even the smallest garden can supply.

Creating a natural-looking water feature will provide opportunities for the imaginative gardener to design and build, or to modify and existing pond so as to make it more wildlife-friendly. Before diving in to your water feature project, take a trip into the countryside and observe how nature provides water in order to satisfy the requirement of creatures of all sizes. Compare the areas where small birds and animals drink and bath to those that are frequented by larger birds and animals. At the same time observe the surrounding vegetation, and its role in satisfying the needs of different bird and animal species.

Back in your garden, take a good look around and decide where you are going to site your water feature, how big it will be, and what it will provide for nature's creatures. It may be as small as a simple bird bath, or a pond, or a stream with waterfalls and pools stocked with indigenous fish, or even a wetland. Your choice will depend on what you can afford, the slope of the property, the availability of an ample water supply, and the size of your garden.

The bird bath

If your garden is very small, you may only have room for a bird bath. These only take up about 1m2 of area. There are many different bird baths available that only require you to purchase it, cart it home, and erect it in your garden. You can, however, get great satisfaction from constructing your own, natural looking bird bath. It is advisable to put the bird bath in a more sheltered part of the garden so that the shy birds, which would not use a bath in open areas, can use the bath for drinking and bathing. If cats are not a problem, the bird bath can be placed or built on the ground so that the ground loving birds and small animals can use it. A site under an overhanging branch is a good idea as the birds can fly up onto the branch if danger in the form of a neighbourhood cat should appear.
It is quite easy to construct a natural-looking bird bath on the ground. First excavate a shallow hollow about 300mm at its deepest point. Then line it with fairly thick plastic sheeting (500 micrometres thick). Mix a mixture of 3 parts of river sand with 1 part of cement and add sufficient water to make it easy to work with. Next, cover the entire surface of the plastic sheeting with cement mix to a thickness of about 75mm. Make sure that the edges of the bath are level and that it is about 75mm to 100mm deep in the deepest part. The depth at the edges should be no deeper that 25mm so that the smaller birds can bathe in it. Pack rocks around the edge of the bath and cement them in place. When the cement has set, but is still damp, prepare a wash of 1 part cement to 1 part fine plaster sand and spread a thin layer over the cement. Cover with plastic or a tarpaulin and allow the cement to mature for 3 or 4 days. Fill with water and wait for the birds to discover it.

Building a water feature

Normally the average garden does not include a pond. Commercially available ponds are not affordable to most people. However, don't be discouraged. Water features, including a pond can be constructed, at a fairly low cost. They look attractive, and also serve the requirements of the bird and wildlife community.

There are three options available to you if you decide to install your own pond or water feature. You canpurchase a ready-made fibreglass pond shell, or you canuse a plastic pond liner, or if you are energeticconstruct your own cement and concrete feature. Whichever option you choose, you will have to start by digging a hole that is big and deep enough to contain your water feature.

Pond shells can be bought at most nurseries or garden centres. Although these are the most costly of the three options available to the do-it-yourselfer, they are easy to install, durable, and are not prone to leaking.

When digging a hole for a pond shell, make it about 10cm deeper than the shell itself. Line the hole with a layer of river sand and position the shell on top of this. Add or remove sand to achieve the correct height. The edges of the pond should be slightly higher than the surrounding ground so that soil will not be washed into it. Use a spirit level on a long plank to ensure that the pond is level. If you want to create a wetland area next to the pond, you can tilt the pond slightly so that excess water can overflow into the wetland.

Once the levels have been established, fill in the spaces around the pond with river sand. This will ensure that the water pressures within the pond are even, and will ensure a longer life for the pond.

Pond liners

Pond liners, such as PVC sheeting, butyl rubber or bentonite clay, allow for more creativity on your part. You can incorporate islands, streams, deep potholes and shallow shelves to create a feature tat will be used by several bird species.

When designing your pond try to make a section that is about 50cm to 75cm deep. This will ensure temperature stability in the water, which is important for fish and other pond life.

When you have sculptured the shape and depth of the pond, line it with a 1cm to 2cm layer of fine plaster sand to prevent the liner from being damaged by sharp pebbles in the soil.

Plastic liners are available from certain nurseries and garden stores, or they can be made up to suit your design. Make sure that the liner is at least 550 micron thick. It is better to use a liner that is specially made for the job than to try to glue different pieces together to make up the required shape. Glued joints seldom last and will leak in a very short time. PVC sheeting is best for these liners as it can be repaired using special glue.

Polyethylene sheeting can also be used, but it has a much shorter lifespan PVC, which should last for up to 20 years.

When the hole is lined and the liner is adjusted, fill the pond with clean water.

You can now position rocks around the edges and trim the overlapping plastic to complete your pool.
Concrete pools

Pools that are constructed of concrete are the most difficult and expensive option. The construction should be carefully planned beforehand, even before the digging of the hole is started.

The structure can be shaped as you please, will not be affected by the elements, and will also be permanent. Careful preparation of the site and concrete is extremely important, and if not carried out correctly will lead to leaks, which are often difficult to seal.

Plan your pool in the same way that you would using a pond liner, letting your imagination guide you.
After digging and shaping the hole, compact the soil thoroughly so as to prevent cracking later. Line the hole with welded galvanised chicken mesh to serve as reinforcement for the concrete. When casting the concrete make sure that there is a gap of about 25mm between the soil and the wire, so that the concrete will be on both sides of the wire. This can be achieved by pulling the wire up as you pour in the concrete or by placing small stone spacers under the wire. It is essential that all of the concrete is laid in one day; if joins are made in the concrete leaks are likely to develop later. The concrete layer should be at least 75mm thick.

When you fill the pond with water, the concrete will release toxic salts into the water. Due to this, the pool should be left to stand for two to three weeks before being drained and refilled with clean water. The fish and plants can now be added to the pool.

Establishing life in your pond

Having installed your pond, you will have to introduce life into it. If possible use borehole or rain water to fill the pond, rather than treated water which contains toxins that are harmful to pond life. It is easy to redirect rainwater off the roof of the house into your pond by means of a 50mm diameter polyethylene plastic pipe that can be buried underground. Regular flushing with rainwater will help to maintain the quality of the water and life in the pond.

A great deal of pond life will arrive under its own steam, but if you introduce some water from a healthy established pond, dam or river you will speed up the colonisation process. Fish will have to be introduced. Try to obtain indigenous species such as Tilapia and minnows. Avoid introducing Barbel into the pond as these will devour other fish species.

Before introducing fish you should establish indigenous water plants such as water lillies, etc. Your local indigenous plant nursery will be able to advise you on the plants that you require. It is best to plant them in plastic nursery bags in the bottom of the pool. In order to establish equilibrium, the plants should cover about 50% of the pool surface area when established.

If your pond is large enough, you may be able to attract Jacanas, Bitterns and some of the smaller Herons, all of which appreciate the type of food that is found in a well-balanced water feature.