Made for transport, used for recreation

Canals are man-made waterbodies that were once important for the transport of goods but nowadays are mainly used for recreation – both on the water and along the towpath. Most canals are in the lowlands, but they snake around the uplands in some parts of the country.

Canals are not quite like any other freshwater habitats – people often say they are like long ponds. However, because they are quite deep, narrow and gently flowing, they are more like the deep, sluggish and rich rivers that would once have coursed across lowland floodplains before land drainage engineering took hold.

2,500km

of canals in the UK

95%

of canals have impacted water quality

of UK freshwaters are canals

2,500km

of canals in the UK

95%

of canals have impacted water quality

of UK freshwaters are canals

How healthy are our canals?

The best canals are true wildlife jewels but the overwhelming majority, like most of Britain freshwaters, are damaged by water pollution. All but a few suffer the twin impacts of pollution and, on popular canals, the regular to-ing and fro-ing of boats, which churn up sediments and leave the water brown, muddy and turbid. A small number – like the Montgomery Canal – still have clean and uncontaminated water and are outstanding freshwater habitats.

There are two sides to every canal – literally. The towpath side, where horses once plodded along pulling the boats at a very leisurely walking place, is the more disturbed side and often banked with steel sheet piling for mooring up. The other side of every canal, known as the ‘offside’, is often inaccessible, frequently has more natural banks and may have tall emergent plants providing natural cover.

Red and yellow painted canal boat on canal with lush vegetatian.

- Narrowboats on the Oxford Canal at Oxford. Oxfordshire, England, UK

What can you find living in a canal?

In the best and cleanest canals, a very wide range of freshwater plants and animals, including the most sensitive plants and creatures, are at home. Sadly only a tiny minority reach this standard – and these are wonderful biological refuges.

Being permanent, canals they support fish, so have those plants and animals that are happy to co-exist with fish – these account for around 50% of all freshwater creatures. Tolerant and widespread creatures, such as Moorhen, Mallard, Roach and Two-spotted Water Slaters, are able to use even polluted canals as habitat.

Marginal plants that aren’t much affected by water pollution and can grow healthily in the soupy water, like Common Reed and Branched Bur-reed, provide habitat for a range of birds, including the Sedge Warbler and occasionally the much less common Cetti’s Warbler.

Species directory

- Sedge warbler (Acrocephalus schoenobaenus).

Why are canals important?

Polluted canals are not particularly important for their underwater wildlife. But for animals that live on or near water and aren’t too fussed about pollution, canals can be great.

The tunnels and bridges along canals can be important bat habitats and, where there aren’t any mink and the banks are well-vegetated, canals can be used by water voles. The commoner coarse fish are present, and where there are fish you will naturally see the occasional kingfisher or heron, or perhaps a visiting otter. None of the organisms depend on the canals but they use what the canals provide.

- Water Vole.

How Freshwater Habitats Trust is helping canals

Freshwater Habitats Trust developed the national monitoring method for assessing the biological condition of canals – called Canal PSYM. This can help people assess whether the condition of their canals is getting better or worse. But we’ll mainly be highlighting the need to protect the most important canals biologically – the irreplaceable waters like the Basingstoke Canal in southern England and the Montgomery Canal on the border of England and Wales. These are both canals with exceptional water quality – for these to maintain their quality, vigilance will be needed.

Often the best thing to do for wildlife is to make some clean ponds alongside the canal, rather than trying to do the impossible or unnecessary, like reducing boat traffic. After all, canals are mainly for boats.

Canal with stone bridge and trees either side. Blue cloudy sky.

- Montgomery Canal at Frankton, Shropshire, UK