8.6 Ponds

Ponds are paradise for wildlife. They are havens for frogs, toads, newts, caddis nymphs, water beetles, water spiders, kingfishers, herons, bats, water lilies, marsh cinquefoil, water mint, and bulrushes to name but a few species.

Thousands of ponds have been destroyed throughout Britain during the last 100 years. So yours can make an important contribution by providing a much-needed habitat for a variety of wildlife species.

If you are making an entirely new pond, site it in a sunny, but sheltered, area. Keep it clear of overhanging trees, as falling leaf litter can reduce the oxygen content and destroy aquatic life.

Locate it close to other water sources so you have an emergency supply of water in times of drought. Site it well away from underground gas and electricity supplies.

Before digging your pond, you should mark its boundaries with pegs and string. Start anytime if it is dug in late winter or early spring, it will develop quicker.

The larger your pond, the greater the diversity of plant and animal life it will sustain. For practical purposes and easier management, dimensions of around 5 to 10 metres are the norm.

The pond should be about one metre deep, even if only at one end, to prevent it freezing in winter. If it is much deeper, safety precautions for visitors and your management team should be implemented.

Most ponds are oval in shape and slope gently towards their edges. This enables herons to wade comfortably while fishing, and allows other creatures such as frogs, newts, and ducks to get in and out more easily. The creation of shelves and ledges provides variations in water depths and attracts a wider range of aquatic plants. The soil you excavate can be sown with wildflower seeds or planted with shrubs to form artificial embankments.

Cut a trench round the border so you can bury the ends of the pond-liner. Ensure the lip of the pond is level all the way round. Pond-liners can be made with PVC material, polythene, and butyl rubber. The main advantage of butyl rubber is it is difficult to puncture. Clay can also be used. Do not forget to allow some additional material for anchorage purposes (see below).

Start to line your pond by digging a hole and removing large rocks. Next, you cover the hole with a layer of old carpet or thick brown packaging paper. You then lay your pond-liner over the hole and ensure it falls down into position on top of the carpet or paper. A mat of polyester covering is placed over the pond-liner to protect it from sunshine and sharp objects and to provide a good grip for soil. A thin layer of subsoil (not too rich in nutrients) is poured over the mat.

Most ponds are oval in shape and slope gently towards their edges. This enables herons to wade comfortably while fishing, and allows other creatures such as frogs, newts, and ducks to get in and out more easily. The creation of shelves and ledges provides variations in water depths and attracts a wider range of aquatic plants. The soil you excavate can be sown with wildflower seeds or planted with shrubs to form artificial embankments.

Cut a trench round the border so you can bury the ends of the pond-liner. Ensure the lip of the pond is level all the way round. Pond-liners can be made with PVC material, polythene, and butyl rubber. The main advantage of butyl rubber is it is difficult to puncture. Clay can also be used. Do not forget to allow some additional material for anchorage purposes (see below).

Start to line your pond by digging a hole and removing large rocks. Next, you cover the hole with a layer of old carpet or thick brown packaging paper. You then lay your pond-liner over the hole and ensure it falls down into position on top of the carpet or paper. A mat of polyester covering is placed over the pond-liner to protect it from sunshine and sharp objects and to provide a good grip for soil. A thin layer of subsoil (not too rich in nutrients) is poured over the mat.

The pond is then filled with water from a tap or natural source. Tap water has the disadvantage of being chlorinated so it must be allowed to stand for a few days before any plants or mini-beasts are introduced. When the pond is full, the pond-liner is fastened into the encircling trench with soil before being trimmed and edged with turf.

You should allow at least one full week before putting aquatic plants into your pond. Plant them between late April and early September. Use plants from a reputable supplier or ones you have obtained from another pond-owner. DO NOT take plants from the wild to grow in your pond.

Different plant species prefer different depths of water. Crowfoots and starworts like deeper water. Yellow and white water lilies float on the surface. Forget-me-not, cuckoo flower, marsh marigold, yellow flag iris, globe flower, marsh cinqefoil, skullcap, purple loosestrife, and bistort will be in their natural habitat at the edge of your pond. Nowadays many garden centres supply suitable plants but it is wise to check with a wildlife expert on species to prevent spreading non indigenous plants in the wild.

Pond life

You may find the pond attracts frogs and toads naturally. If you are VERY careful you could transfer spawn from another pond, however this is generally unadvisable. Only introduce spawn into your pond if: 1) your pond definitely does not have an existing frog population, 2) you have made sure you are not transferring any invasive plant species with the pond such as Canadian Pondweed, Crassula helmsii, 3) the frogs in the pond you are transferring from are free from disease.

Do not try to introduce great crested newts into your pond. They are protected by law and it is an offence to cause them or their habitat any damage or harm. Of course, if your pond is home to great crested newts that have arrived there naturally, it is a great bonus, as they are rare in Sheffield and are both a local and national priority for conservation.

You may want to stock your pond with fish. If so, you should remember they will prey on other aquatic species like dragonfly larvae and tadpoles depriving your pond of lots of interesting native wildlife. It may be worth remembering that a pond buzzing with damselflies and dragonflies and teaming with amphibious life can be just as attractive and more natural than a pond full of fish.

If there is already a pond at your wildlife site, you can improve its potential. For example, you can remove sizeable quantities of Canadian pondweed from the surface by raking it or by removing it by hand. Leave the pondweed at the edge of the water for at least a day to allow aquatic creatures to crawl out of it and back into the water.

Pond maintenance

The branches of overhanging trees and shrubs can be cut back to allow more sunlight onto the pond surface. Ensure there are no Tree Preservation Orders at the site before you start to trim branches.

Avoid being over-enthusiastic about tree lopping, however. Trees can visually enhance your pond and their branches will provide perching places for kingfishers and flycatchers. If the bed of your pond is choked with dead vegetation you should clear it by hand or with a rake, but do not remove too much silt, as it provides a home for many species of pond inhabitants, including the larvae of many insects including colourful dragonflies and damselflies. Do your pond dredging in autumn, because many creatures will be hibernating in the mud or underwater vegetation in winter and should not be disturbed.

A favourite time for pond-construction is between September and December. This generally causes the least disturbance to wildlife. By then the bird breeding season is over and family groups of birds and mammals have dispersed, reducing the need to congregate for food and shelter at individual sites. However, in severe weather, especially when the land is frozen over with snow or ice, your pond could be a sanctuary for birds wanting to drink. It could also be a feeding place for ducks, herons, or even kingfishers unable to get their food elsewhere. No matter when you work on your pond, some damage will be unavoidable. Use your discretion and try to keep disturbance to an absolute minimum.

Watch out for algal bloom. This is an explosion of green algae in your pond that can destroy other forms of aquatic life by using up all the oxygen. Rake off coverings of algae from the surface of the water. Algal blooms should be reported immediately to the Environment Agency. Telephone numbers can be obtained in your phone book. If unchecked, the pollution could cause untold damage to aquatic life and, possibly, prove harmful to humans.

Landlife produce a useful publication on how to design, build and maintain a pond for wildlife called ‘The Wildlife Pond’ (See section on meadows for contact address).

Further information about ponds, frogs, toads, newts, lizards, and reptiles is available from:

Information about licensing and licences to handle reptiles and amphibians can be obtained from:

Tel 01924 387010