The conservation value of Shropshire's canals

Shropshire botanical Society Newsletter - Spring 2000 - pages 9-14

Alex Lockton

 

Canals represent a dilemma to conservationists, in that it is difficult to justify their existence on ecological grounds alone. They are nothing other than purely artificial structures, created for, and maintained by, economic activity. If a canal is abandoned, as a lot of them were during the first half of this century, it quickly silts up and loses all its ecological interest. Only for a brief time - a few decades at most - is there a habitat of undisturbed open water that often supports an interesting and valuable flora and fauna. It is difficult to argue that huge sums of money should be spent on the upkeep of abandoned canals (and it is very expensive indeed maintaining aqueducts and locks and so forth) when there are more natural habitats being destroyed at such an alarming rate. This argument would seal the fate of the canal system except for two things: firstly, some canals are now the last refuge of rare biodiversity species that the UK has a legal obligation to conserve; and, secondly, there is no need for a conflict between conservation and navigation. The two can coexist perfectly easily and, indeed, it is largely the enjoyment of the countryside that people take to the canals for. People don't choose to go to canals for the delights of steel pilings, stagnant water and brown rats - they'd much rather have water-lilies and kingfishers, if they had the choice.

Shropshire's canal system is on the verge of complete destruction of its natural history. Its history and historical ecology is a fascinating subject, and indicates what it could be like again in the future. There is still a chance that the best remaining bits could be saved, if the authorities act appropriately. For this article I shall attempt to give a summary of each of the canals in the county (and it might be useful to follow Charles Sinker's example and annexe part of Montgomeryshire for this purpose) and examine the past and present conservation value of each.

 

The Shropshire Canal

The first canals in Shropshire were built in what is now Telford, starting in about 1788, and were used for transporting coal, ore, iron, limestone and sand between the various factories and mines in that area. The system was for a long time entirely isolated from the rest of Britain's canal network: links to the Severn provided a water-borne route to the rest of the world. Eventually there was a whole network of canals criss-crossing the district, all of which were smaller than the standard long-distance canal, with a narrower channel and smaller locks. It was a self-contained system, and was largely displaced by the railways by about 1860. Small sections still survive, but they are un-navigable and are completely isolated from all other waterways.

Rev. Edward Williams was the first botanist on the scene, as was generally the case in Shropshire, especially where water plants were involved. In the Lilleshall Canal - the very first stretch built - he found Fennel Pondweed, Potamogeton pectinatus, probably between about 1790 and 1800. This was the first record of the species in the county. Fennel Pondweed is not a rare plant, and has subsequently been recorded in most of the canals and in several rivers and meres. It is interesting to note, however, that all the oldest records are from canals, and it wasn't until nearly a hundred years later that it was definitely recorded from any other type of water body. This is because it is a plant of eutrophic (nutrient-rich) water - and the rivers and meres at that time were too low in nutrients at that time for it to thrive there.

In subsequent years a number of other interesting plants were recorded in the Lilleshall Canal, including Fan-leaved Water-crowfoot, Ranunculus circinatus, Ivy-leaved Duckweed, Lemna trisulca, and the Branched Bur-reed Sparganium erectum ssp. microcarpum, by W.H. Painter in 1904. Fine-leaved Water-dropwort, Oenanthe aquatica, was found "in a pool by the side of the canal" by R.G. Higgins in about 1841. That observation by Higgins is a reminder that it is not just the main channel of a canal that has ecological interest. There are frequently reservoirs, overflow ditches, seepages and similar habitats associated with canals which have considerable value of their own. Water plants can often move from canals to other water bodies, and vice versa, and the canals may have once played an important role in moving certain plants around the country.

Another characteristic canal plant is Narrow-leaved Water-plantain, Alisma lanceolatum, which was recorded on a canal at Madeley by Painter in 1895. This was its only known site in Shropshire when Sinker's Flora was written, it having been rediscovered there by Franklyn Perring in 1975; but further searches since then have revealed it to be present in a number of other locations throughout the county, and it is no longer considered to be a rarity.

All that is left of the Shropshire Canal network is a couple of stretches at Blists Hill, the Hay Inclined Plane and several reservoirs dotted around Telford. The latter have mostly been converted to ornamental lakes. The Blists Hill canal is not of very significant ecological interest. It does not belong to British Waterways, and it seems very unlikely that it will ever be used for navigation again, but the Ironbridge Gorge Museums and the Environment Agency are still willing to spend money to maintain the 1.5km length that still contains water.

The most recent survey data we have dates from 1995, when the main part of the canal was almost dry. There was a plan to restore it, but I am unaware of whether that has happened. The only species of any significance recorded at that time was the Alisma lanceolatum, so it would be reasonable to say that it is not a site of any particular botanical importance. However, it would be interesting to see what species turn up if and when it is restored.

 

The Shrewsbury Canal

The Shrewsbury Canal was constructed in the 1790s, primarily to bring coal from the Telford coalfield to Shrewsbury. It runs from the Buttermarket in Shrewsbury, past Attingham Park, to Trench in Telford and, after a while, was extended to Newport to join up with the Shropshire Union Canal. It was built on a narrow gauge, like the Shropshire Canal, and includes a long tunnel near Atcham, which is of interest for bats.

Like most of the canals, it was bought up by the railway companies in the mid-19th century and eventually closed down. It is now dry for most of its length, but a large part of the route remains discernable on the map as well as on the ground. For a long time it was designated on the County Structure Plan for conversion to a cycle path, but that does not seem to have got anywhere yet. It is unlikely ever to be restored because (i) it does not belong to British Waterways, (ii) it is a narrow canal, and (iii) there are several serious obstacles now in its way, including the Shrewsbury bypass.

Edward Williams seems not to have devoted much attention to the Shrewsbury Canal. He collected Hemlock Water-dropwort, Oenanthe crocata, at Berwick Wharf and fished Horned Pondweed, Zannichellia palustris, out of the water at Uffington. This was a first county record for another eutrophic water plant which, like Fennel Pondweed, later started Frogbit, Hydrocharis morsus-ranaeturning up at the meres. On August 8th 1832 William Leighton and Charles Babington visited the Shrewsbury Canal and found, among other things, Fennel Pondweed "in great abundance," Greater Duckweed, Spirodela polyrhiza, (a first for the county), Arrowhead, Sagittaria sagittifolia, (another first), and Frogbit, Hydrocharis morsus-ranae. They also recorded Narrow-leaved Everlasting-pea, Lathyrus sylvestris, presumably growing in the hedgerows alongside. It is quite an uncommon plant in Shropshire these days and, although it may have persisted alongside the canal until the 1970s, it seems to have gone from there now.

Frogbit, Hydrocharis morsus-ranae

Leighton seems to have collected, but not at first identified, one of the Shrewsbury Canal's rarities, Flat-stalked Pondweed, Potamogeton friesii. This species, which is now almost extinct in the county, was known there until the 1950s. Another rarity, Floating Water-plantain, Luronium natans, was not found until about 1880, when W.E. Beckwith recorded it. By this time the canal had been linked to the Midlands waterways for many years, and was in fact already pretty much defunct, so the origin of this plant at this site cannot even be guessed at. Another find in the 1880s was Opposite Stonewort, Chara contraria, for which there is a specimen collected by James Groves. This alga is now considered nationally scarce, and is currently known in only one site in the county. Long-stalked Pondweed, Potamogeton praelongus, is yet another county rarity, recorded at about that time by R.M. Serjeantson.

It seems that the Shrewsbury Canal may have had a rather finer flora than the Shropshire canal did. Perhaps that is a consequence of it running through open countryside, rather than the industrial pollution of Coalbrookdale; but it is just as likely that the botanists of Shrewsbury were simply more diligent.

Water-soldier, Stratiotes aloidesThe current status of the Shrewsbury Canal is not good. A fairly long stretch is still in water between Ditherington and Haughmond Hill. This is managed by the Borough Council with the interference of the locals, and it has the dubious virtue of being one of the county's best site for alien water plants. In a good year you can find Curly Waterweed, Lagarosiphon major, Water Fern, Azolla filiculoides, Least Duckweed, Lemna minuta, Parrot's Feather, Myriophyllum aquaticum, Canadian Waterweed, Elodea canadensis, and Water-soldier, Stratiotes aloides; the latter being considered a rare native plant in some parts of Britain, but an introduced menace around here.

Several other stretches of the Shrewsbury Canal are still in water or just damp. At Uffington and Berwick Wharf there is water, and even the dry sections elsewhere often have extensive stands of Common Reed, Phragmites australis. The OS map shows several other stretches in water, but we have few recent records. Perhaps a survey of the route would be an interesting project.

Water-soldier, Stratiotes aloides

 

The Llangollen Canal

There is a confusing history to the Llangollen Canal, with the many names that it has had. Originally it was intended that there would be a magnificent canal running from Shrewsbury to Chester and beyond, linking the Severn, the Dee and the Mersey. This was to be the Ellesmere Canal, and Netherport on the Wirrall was even renamed Ellesmere Port in anticipation. It was envisaged during the height of canal mania, but was never completed. Instead, it ended up running from Llangollen to Weston Lullingfields, not reaching any useful industrial or population centres at all. Subsequently it was extended eastwards across Whixall Moss, to join up with the Shropshire Union Canal at Market Drayton, and the "Weston Arm" towards Shrewsbury was eventually filled in. So what we call today the Llangollen Canal, which is marked on Ordnance Survey maps as the Shropshire Union Canal, runs approximately east-west across the northernmost part of the county, from Chirk past Ellesmere and Frankton Locks, and onwards past Whixall Moss towards Whitchurch.

The Llangollen Canal appears to have been started in 1794 in the vicinity of Ellesmere and Frankton Locks. A branch towards Llanymynech was constructed to bring limestone from the quarries there. Meanwhile, the main line from Ellesmere to Shrewsbury was being started. It was rather later that the aqueducts over the Dee and Ceiriog were built, owing to the cost and difficulty of constructing these magnificent structures, and the final connection to the feeder between Llangollen and Pontcysyllte was not opened until 1808.

This sequence matters somewhat from the point of view of the colonisation of the canal by aquatic plants. We have no botanical records that are definitely from the canal until rather later. J.E. Bowman was the first to make records. He was born in 1785 and died in 1841, so it not be unreasonable to suppose that many of his records date from between 1805 and, say, 1830. He described a hydrological link between the Mere at Ellesmere and the Llangollen canal in his record for Starfruit, Damasonium alisma: "abundant in Ellesmere Mere and adjoining ditches and canal." This is fascinating, because Starfruit is not described anywhere else as a canal plant. It seems highly likely that, when the canal cut through the peat bog at The Moors, there was ample opportunity for colonisation of this new and otherwise isolated water body, from the Mere itself. Bowman also recorded Blunt-leaved Pondweed, Potamogeton obtusifolius, at "Ellesmere" - quite likely also to have come from the canal.

Other plants soon came to colonise the new canal. By the mid to late 19th century, when the canal was already in decline, a marvellous selection of rare species had been recorded. Serjeantson collected Red Pondweed, Potamogeton alpinus, in 1880; and William Beckwith and William Phillips collected Long-stalked Pondweed. Flat-stalked Pondweed was added to the list in 1884, and then, in 1893, Rev. J.D. Gray found Floating Water-plantain. This latter plant is of particular significance, because it is of national and international rarity. It is so rare now that you need a licence from the government to collect it.

There is an interesting sequence to the arrival of Floating Water-plantain in the Llangollen Canal, and subsequently into the Montgomery Canal. There is a theory that it floated down from Lake Bala, along the River Dee, through the feeder stream at Llangollen, and subsequently all the way along the Llangollen canal to Ellesmere. The earliest suggestion of this that I have come across was by Oswald Mosley Feilden in the Record of Bare Facts in 1906. But we also know that there used to be Floating Water-plantain in the Mere at Ellesmere, which was hydrologically linked to the canal some ten years or so before the extension to Llangollen was completed. It is therefore possible that this species entered the canal from The Mere, and that at least some of the plants which remain in the Montgomery Canal are derived from this source, preserving the genetic heritage of a lowland population of this now mostly upland species.

Today the Llangollen Canal in Shropshire is not of much ecological interest. It is connected to the inland waterways network and is constantly boated. The motor-powered craft now used on canals stir up the mud from the bottom, and the wash erodes the banks. As a consequence, the water is too opaque for submerged species, and the marginal plants get washed away. To prevent damage to the banks, British Waterways puts in vertical metal pilings or brick walls, which leave no niche for plants at all. This is the situation now throughout all the Shropshire sections of the canal, and even at Llangollen it is thought that the Floating Water-plantain may have become extinct.

If there is one ray of hope for the Llangollen, it is that the water quality is probably good, if only there was not so much suspended silt. Experience from other canals shows that all it takes is a short side arm of ten metres or so, which is undisturbed, and the water clears enough to allow the aquatic flora to flourish. Perhaps in future there will be the opportunity to develop such side-arms as nature reserves, to enhance the overall value of the canal. It is a possibility - and this is pure speculation - that the water from the Llangollen Canal could be part of the reason why Cole Mere has retained its unique English population of the very rare species Least Water-lily, Nuphar pumila. The overflow from the canal presumably brings a supply of clean, nutrient-poor Welsh mountain water that helps to maintain the quality of the mere. To clarify that hypothesis, we would need to know what proportion of the mere's water is derived from this source.

 

The Prees Branch Canal

The Prees Branch Canal is a side arm of the Llangollen which runs from the south side of Whixall Moss towards Wem. It was never completed and part of what was built has now been filled in. In the 1960s it was found to have a rich flora, including Frogbit, Red Pondweed, Needle Spike-rush, Flowering Rush, Butomus umbellatus, and the hybrid sedge Carex x boeninghauseniana - the only place where this particular hybrid has been recorded in the county. But in the 1970s an ideological battle was fought over the development of this canal for a marina, where boats using the Llangollen Canal could dock. It was argued, successfully, that development would not harm the ecological interest of the site, and the Shropshire Wildlife Trust ended up with the southern end of the canal while the marina went ahead. Subsequently, all aquatic plants promptly disappeared from the marina and the northern parts of the canal, whilst even the reserve has subsequently and steadily declined in quality. It still has Tubular Water-dropwort, Oenanthe fistulosa, and water-violet, Hottonia palustris, but the Frogbit seems to be on the verge of extinction there. This is perhaps a lesson to be remembered for future debates on the consequences of restoration.

 

The Montgomery Canal

Arrowhead, Sagittaria sagittifoliaWhat we now call the Montgomery Canal was originally the Llanymynech Arm of the Ellesmere Canal, later extended to Newtown as late as 1819. This canal has some 19km in Shropshire and the rest (currently about 34km) in Montgomeryshire. For the purposes of this article I shall include the Welsh sections even though it is at present completely isolated from the English length by a short dry stretch.

The oldest record for the Montgomery Canal is by Edward Williams at the end of the 18th century. He found least Bur-reed, Sparganium natans, "near the Queen's Head turnpike." That species is now almost certainly extinct in Shropshire. Other rare plants recorded include Long-leaved Pondweed, P. x zizii, by Beckwith in 1885, and Floating Water-plantain - first recorded in the Montgomery Canal as late as 1906, by Professor W.N. Jones of London University. Another classic species of this canal is Grass-wrack Pondweed, which was first collected at Welshpool in 1938 by Miss S. Haines, who I think may have been the daughter of Henry Haselfoot Haines, once the Conservator of the Forests of India.

Arrowhead, Sagittaria sagittifolia

The Montgomery Canal is extremely important for conservation in Britain. It has an advantage over most canals from its situation in the foothills of Wales. It is fed by the River Severn and in places actually merges with it. This gives it a running supply of unpolluted water which, once slowed down within the canal itself, creates a superb habitat for aquatic species. By a curious chance, it forms the last really substantial refuge for a whole range of what were once typically English lowland species, but which have declined in this country as a result of eutrophication of water bodies.

So, uniquely among the canals of Shropshire (and its near neighbours), the Montgomery still contains all the plants of conservation interest that used to occur in this county. It has literally millions of plants of Floating Water-plantain; several species of pondweed: compressus, praelongus, friesii and alpinus; lots of Frogbit; Needle Spike-rush; Alternate Water-milfoil; and even a rare stonewort, Nitella mucronata var. gracillima. One special feature is the presence of freshwater sponges, which are so rare in this country that British Waterways' ecologists have to send specimens to Russia to have them identified. From the Shropshire lengths, all these species have virtually disappeared since the restoration and re-opening of the canal to boat traffic; but in the Welsh parts they are thriving.

The battle over the restoration of the Montgomery Canal started as long ago as the 1960s. In about 1980 an Act of Parliament was passed, permitting restoration for navigation on condition that a number of off-line reserves were built. It was intended that these would be like the Prees Branch Canal before it was converted into a marina, but in the event only a few reserves have been constructed, and they have ended up more like Prees Branch after it was trashed. They have not been successful in conserving the typical canal plants, although they are quite interesting as ponds.

The future of the Montgomery Canal is very much in doubt. Restoration in Shropshire has proceeded in exactly the same way as with the Prees Branch: promises that conservation will be catered for, followed by almost complete destruction of the aquatic flora. It is only the fact that boats cannot cross over into Wales that has saved the southern half from a similar fate. It would cost a fortune to restore the Vyrnwy Aqueduct and the Guilsfield Arm (now dry) and the last few abandoned sections into Newtown, so perhaps there is still some time. But surely there must be some way of reconciling boat traffic with conservation, to preserve this, arguably the most ecologically important canal in Britain.

 

The Shropshire Union Canal

Although almost all the canals in Shropshire are labelled on the OS map "Shropshire Union Canal," the one that is now given that name is Thomas Telford's Birmingham & Liverpool Junction Canal. It was finished as late as 1835 (after Telford's death) and was apparently designed to be straight and fast, in order to compete with the railways. There are almost no botanical records for the SU Canal, except for some recent records of the alien species Orange Balsam, Impatiens capensis. One cutting is designated a SSSI for the geological exposures, however.

 

The Newport Canal

Joining the Shrewsbury and the SU Canals was the Newport Canal, which thrived for a while in the middle of the 19th century. In 1897 William Phillips recorded Whorled Water-milfoil, Myriophyllum verticillatum, there - the only find of this nationally scarce species in a canal in Shropshire. He also found Frogbit. Even now parts of the Newport Canal are designated SSSI because of their interest. Frogbit is there, along with Long-stalked Pondweed and the nationally scarce (but here introduced) Fringed Water-lily, Nymphoides peltata. It is interesting to know that Grass-wrack Pondweed was found by George Claridge Druce at Aqualate Mere just once, in 1929. It is not really a species of the meres, and it is quite possible that it arrived there from the nearby Newport Canal - a stretch that is now dry.

Perhaps the greatest advantage of the Newport Canal is that it is isolated from the Inland Waterways network and is not the subject of a restoration scheme. Although it is far less valuable, ecologically, than the Montgomery Canal, it may have better prospects in the near future. However, without the clean water supply from the Welsh mountains that the Montgomery enjoys, one might wonder how long it can sustain its present population of uncommon species.

 

The Leominster Canal

There is not a lot to say about the Leominster Canal. It was never actually completed, and has now almost gone again. There appear to be just two records for it. The sedge Carex x pseudoaxillaris (C. otrubae x remota) was recorded there by Edward Cleminshaw in 1901, and Yellow-wort, Blackstonia perfoliata, is listed for the canal bank in Leighton's Flora. A very short section in Shropshire is still shown on the OS map, but we have no recent records.

 

Conclusions

The canals of the Welsh borders occupy a strategically important location in Britain, being in the rural and relatively unpolluted foothills of the Welsh mountains. This makes them especially promising for the long-term conservation of a variety of rare and endangered plants, including some for which Britain has an international legal responsibility. To date there have been hopelessly inadequate efforts to reconcile restoration and conservation, resulting in complete destruction of the ecological interest of several canals, which has been compensated for in an almost meaningless way by the construction of some ponds. On the other hand, several canals have also been lost through neglect.

In the Montgomery Canal in particular, conservation must be the highest priority in future, with recreational use being permitted only in ways that does not destroy the aquatic flora. If this means that boats would have to leave their engines off and be towed by horses (or towpath vehicles) then why shouldn't they? It is a privilege to travel along such a beautiful canal - if this was the condition for permission to do so, I have no doubt that many people would.

Other canals in Shropshire are, ecologically and sometimes physically, in a desperate state. The Llangollen has the potential to be a very fine water body, but is apparently in a state of rapid decline. The Newport is still a SSSI, but for how long, I wonder? Most of the rest are as good as lost. Whatever happens, the Botanical Society will continue to record and monitor all the canals as long as they exist, and can report honestly and scientifically on the state of their flora.

The modern names of canals in Shropshire

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