The Severn Tunnel/Chapter 1
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| Telford’s Bridge, Gloucester |
The Severn Tunnel:
ITS CONSTRUCTION AND DIFFICULTIES.
CHAPTER I.
THE COUNTRY IN THE IMMEDIATE NEIGHBOURHOOD
OF THE SEVERN TUNNEL.Desription of the SevernThe River Severn, after a long course from its source in Plynlimmon, widens out just below Gloucester into a broad estuary, which has formed a great obstacle to traffic passing between Bristol and the South-West of England and South Wales.
The Severn, as a river, may be said to end at Gloucester, at the point where the turnpike-road is carried, by Telford’s famous bridge of only 150 feet span, over it, for almost directly below it opens into a tidal estuary, which spreads out till, at the point where the tunnel passes under it, it is 2¼ miles wide. The tides in the Severn estuary are known to be the highest in England or in Europe. They are only surpassed in height by the tides which run Description of the Severnup the Kennebecasis River at the head of the Bay of Fundy, in New Brunswick.
The great rise of this tide is caused by the funnel-like shape of the estuary. The tide running round the South of Ireland, and becoming imprisoned between South Wales and the Cornish and Devonshire coasts, as the width of the channel is continually decreasing, mounts up to a great height, till it reaches, at the mouth of the Wye, a height at spring-tides, of 50 feet above low water.
About 26 miles below Gloucester, where the river is 3,700 feet wide, it is crossed by an iron bridge, constructed to carry the Severn and Wye Railway over it, and so form a connection between Lydney and the coalfields of the Forest of Dean on the west bank, and the Midland Railway between Birmingham and Bristol and the docks, at Sharpness Point, which are situated directly below the bridge, on the east. The bridge was opened on the 19th October, 1879.
Before this date there had long been rivalry between the two schemes for a bridge or a tunnel.
The Great Western Railway Company had been anxious to establish a more direct route between Bristol and South Wales, and to avoid the heavy gradients of the Stroud Valley between Gloucester and Swindon. They obtained, many years ago, an Act to construct a bridge over the river near Chepstow, but the project had been abandoned; and they had finally, in 1871, adopted Mr. Charles Richardson’s
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| The Severn Bridge |
The Midland Company had in the meantime given some support to the bridge at Sharpness Point. The two works had been commenced almost simultaneously; but when the bridge was ready for opening, in October, 1879, the only work done at the tunnel was the sinking of five shafts, and the driving of about two miles of small heading.
Among the guests invited to the luncheon by which the opening of the bridge was celebrated, were Sir Daniel Gooch, the Chairman of the Great Western Railway Company, and Mr. Charles Richardson, the engineer under whose superintendence the works of the tunnel were being carried out. Sir Daniel, whose health was proposed at the luncheon, in replying, gave the company present an invitation to attend at the Severn Tunnel in about six weeks, and walk through the headings, which would then be completed. He said: ‘It will be rather wet, and you had better bring your umbrellas.’ Alas, he little knew how wet it was; for Mr. Richardson, sitting near him and hearing these words, had received an intimation, on his way to attend the ceremony, that a great spring had been tapped on the western side of the river, that the pumps had been overpowered by the inrush of the water, and that the whole of the work was drowned.
To Sharpness a considerable number of ships are Description of the Severn.towed up the estuary of the Severn, and docked at Sharpness Point, from which place there is a ship canal, known as the Berkeley Canal, to Gloucester.
Below Sharpness the estuary of the Severn continues to exhibit the same features—a waste of sand at low water and a broad channel of dirty water at high tide. The banks are generally low till we reach Aust Cliff, where the east bank rises to about 100 feet. This cliff shows the geological strata in a very distinct manner, the lower part being of the new red sandstone and the upper part lias. The cliff is famous for the number and beauty of the fossils which are obtained from the lias beds.
On the opposite side of the river there is a small island, on which are the ruins of the Chapel of St. Tecla; and here was one of the ferries by which, in the old days, general traffic between Bristol and South Wales was conveyed across the river. This is known as ‘Old Passage;’ and immediately below the river Wye runs into the Severn, about two miles from the town of Chepstow.
Chepstow, which contains about 3,000 inhabitants, is a picturesque town, with part of the old walls still remaining, as well as the ruins of the castle.
It is a favourite resort for tourists intending to visit the Wye Valley and Tintern Abbey, the latter being about 4½ miles to the north-west.
The tide rises at Chepstow Bridge to the height of 50 feet, and runs up the river Wye at high
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| Sudbrook Chapel |
At the point where the Wye joins the Severn the estuary becomes at once two miles wide, and there is a depth of 70 feet at low water in the deep water-channel known as the Shoots; and about two miles below the Old Passage are the piers, built by the Bristol and South Wales Union Railway Company, where passengers travelling by the trains from Bristol to South Wales used to cross the river by steamboats. This railway and the piers are the property of the Great Western Railway Company, and, considering the difficulties encountered in the passage, a very considerable traffic was carried by the steamboats. Immediately alongside the present piers are the remains of the old wharves and roads by which the coach passengers in the old days were brought over the beach and put on board the ferry barges.
Fifty years ago this was the only route by which travellers from Bristol or Bath could reach South Wales, except by sea.
About half a mile below the ‘Black Rock Pier,’ on the western side of the river, on a point of land which has been saved to a great extent from the wasting influences of the sea by the hardness of the strata of which it is composed, are the remains of a Roman camp. Rather more than half the camp has been washed away by the waves, but the two sides which remain are still very perfect. Some Description of the Severn. antiquaries have questioned whether it were a British, Roman, or even Danish camp, but a careful consideration leaves no possibility of doubt that it was a Roman camp.
The two sides that remain are at right angles to each other, and the camp was probably a square, two sides facing to the river, and the other two to the land.
In the ditch of the camp was built, in early Norman times, a small church, the ruins of which are now known as Sudbrook Chapel, Sudbrook having been a parish itself up to about 200 years ago, when the population having almost entirely deserted it, it was joined to the neighbouring parish of Portskewett.
The point chosen for commencing the works of the Severn Tunnel is within about 100 yards of this Roman camp, on the north side of it.
To the south of the camp the inroads of the sea have made marked progress during the last century.
More than 2 miles from the shore is a small island, known as ‘The Denny,’ on which it is reported that, within a hundred years, a fox, followed from the mainland, was killed. It is still possible, at low water of the spring-tides, to walk to the Denny and return in the same tide, but the journey is not unattended with danger.
Opposite the Roman camp, at a distance of about 5 miles, are the new docks at Avonmouth, and the King’s Road, where ships, waiting to enter Portishead or Avonmouth or Bristol docks, lie at anchor.
Description of the Severn.Rather more to the south, at a distance of about 7 miles, is the dark headland of Portishead, with the docks at its foot. On a clear day, a long strip of the coast in the direction of Weston-super-Mare is to be seen, and at times the island known as the ‘Steep Holm,’ lying below Cardiff, also.
The sea-wall which protected the meadows south-west of the camp has been entirely destroyed for a distance of many miles, and the wasting of the land still continues.
In consequence of the destruction of the sea-wall, the equinoctial spring-tides flow over a vast extent of meadow-land, and on one occasion, as we shall afterwards have to relate, the water passed over the whole of the meadows to a depth of more than 5 feet.
From the Roman camp at Sudbrook there can still be traced the remains of a Roman road, running nearly north-west, to intersect the main road, which passed through Chepstow in the direction of Caerleon.
At rather less than a mile from the camp is the village of Portskewett, beautifully situated, but exhibiting signs of neglect with its ugly, squalid and dirty cottages and farmyards; and above the village rises Portskewett Hill, where the mountain limestone has been upheaved.
The Roman road from the camp continues its course till it intersects the main road at the hamlet of Crick, about 1 mile to the west of which is the Description of the Severn. present village of Caerwent, once the famous Roman station, ‘Venta Silurum.’ The Roman walls remain in fair preservation, and it is believed, that when this station was held by the Roman Legions, the tide from the Severn flowed up to the base of the southern wall, and that the rings to which the boats were moored still remain.
Where these tides flowed is now a rough piece of marsh-land, through which the little river Neddern passes to join the Severn.
The whole of the ground in the marsh is rotten, and before the tunnel was commenced there were enormous springs of bright, clear water rising up in several places.
At about 2 miles farther north than Caerwent, the hills of Wentwood are met with, with ‘Grey Hill’ standing in the foreground. The first spurs of the hills fronting the valley are composed of mountain limestone, the higher parts about Shirenewton of the old red sandstone.
On the east side of the Severn, and for some little distance on the western side, the new red sandstone formation is found in nearly horizontal beds. The first disturbance of this takes place behind Portskewett village, where the mountain limestone has been upheaved and the new red formation denuded. A mile farther up the same limestone has been upheaved between Caldicot and Caerwent, and from there to the base of the hills the strata have been much broken, and the Description of the Severn. consequence has been that all the water from the hills, both from the mountain limestone and the old red sandstone, has found subterranean channels through this broken ground, and, before the tunnel was commenced, flowed out in the valley of the Neddern, and formed the great springs which have been before mentioned.
The Neddern, rising as a small brook in the hills above Llanvair Discoed, sometimes lost the whole of its water in the dry season near the foot of the hills, bursting out again near Caerwent at a point called by the natives ‘The Whirly Holes.’
When the tunnel was being made and a fissure was unfortunately tapped in the rock between Sudbrook camp and Portskewett village, all these underground channels poured their water into the tunnel itself, and almost every well and spring, and the little river itself for a distance of more than 5 miles from the tunnel, became dry.
The little river in its course to the sea from Caerwent, passes the village of Caldicot, much the largest village in the neighbourhood, with its picturesque church, the rector of which, the Rev. E. Turberville Williams, took a most genial interest in all our works; and just below the village are the ruins of Caldicot Castle.
Below the Castle, where the Neddern enters the estuary of the Severn, were Caldicot Wire Works, recently converted into tin-plate works, which gave Description of the Severn. employment to a number of people. The place is known as ‘Caldicot Pyll.’
It is rather a puzzle to an ordinary Englishman to find every little stream where it enters the sea or a greater river, in this district, called ‘Pyll;’ and again to find the same word used all round Glastonbury and applied to the drains in the marshes there. The word in the Welsh is ‘Pwll,’ and corresponds to the English ‘Pool,’ though we seem slightly to have altered the original signification.
This description of the Severn estuary and the country immediately adjoining the tunnel may be found useful in understanding the history of the work itself, and explaining many of the difficulties that were encountered when the works were being carried out. .png)