DOCKS, DRAINAGE, AND BRIDGES.
It will have been observed, from the preceding narrative, how much
had already been accomplished by skill and industry towards opening
up the material resources of the kingdom. The stages of improvement
which we have recorded indeed exhibit a measure of the vital energy
which has from time to time existed in the nation. In the earlier
periods of engineering history, the war of man was with nature.
The sea was held back by embankments. The Thames, instead of being
allowed to overspread the wide marshes on either bank, was confined
within limited bounds, by which the navigable depth of its channel
was increased, at the same time that a wide extent of land was
rendered available for agriculture.
In those early days, the great object was to render the land more
habitable, comfortable, and productive. Marshes were reclaimed, and
wastes subdued. But so long as the country remained comparatively
closed against communication, and intercourse was restricted by the
want of bridges and roads, improvement was extremely slow.
For, while roads are the consequence of civilisation, they are also
among its most influential causes. We have seen even the blind
Metcalf acting as an effective instrument of progress in the
northern counties by the formation of long lines of road. Brindley
and the Duke of Bridgewater carried on the work in the same
districts, and conferred upon the north and north-west of England
the blessings of cheap and effective water communication. Smeaton
followed and carried out similar undertakings in still remoter
places, joining the east and west coasts of Scotland by the Forth
and Clyde Canal, and building bridges in the far north. Rennie made
harbours, built bridges, and hewed out docks for shipping, the
increase in which had kept pace with the growth of our home and
foreign trade. He was followed by Telford, whose long and busy
life, as we have seen, was occupied in building bridges and making
roads in all directions, in districts of the country formerly
inaccessible, and therefore comparatively barbarous. At length the
wildest districts of the Highlands and the most rugged mountain
valleys of North Wales were rendered as easy of access as the
comparatively level counties in the immediate neighbourhood of the
metropolis.
During all this while, the wealth and industry of the country had
been advancing with rapid strides. London had grown in population
and importance. Many improvements had been effected in the river,
But the dock accommodation was still found insufficient; and, as
the recognised head of his profession, Mr. Telford, though now
grown old and fast becoming infirm, was called upon to supply the
requisite plans. He had been engaged upon great works for upwards
of thirty years, previous to which he had led the life of a working
mason. But he had been a steady, temperate man all his life; and
though nearly seventy, when consulted as to the proposed new docks,
his mind was as able to deal with the subject in all its bearings
as it had ever been; and he undertook the work.
In 1824 a new Company was formed to provide a dock nearer to the
heart of the City than any of the existing ones. The site selected
was the space between the Tower and the London Docks, which
included the property of St. Katherine's Hospital. The whole extent
of land available was only twenty-seven acres of a very irregular
figure, so that when the quays and warehouses were laid out, it was
found that only about ten acres remained for the docks; but these,
from the nature of the ground, presented an unusual amount of quay
room. The necessary Act was obtained in 1825; the works were begun
in the following year; and on the 25th of October, 1828, the new
docks were completed and opened for business.
The St. Katherine Docks communicate with the river by means of an
entrance tide-lock, 180 feet long and 45 feet wide, with three
pairs of gates, admitting either one very large or two small
vessels at a time. The lock-entrance and the sills under the two
middle lock-gates were fixed at the depth of ten feet under the
level of low water of ordinary spring tides. The formation of these
dock-entrances was a work of much difficulty, demanding great skill
on the part of the engineer. It was necessary to excavate the
ground to a great depth below low water for the purpose of getting
in the foundations, and the cofferdams were therefore of great
strength, to enable them, when pumped out by the steam-engine, to
resist the lateral pressure of forty feet of water at high tide.
The difficulty was, however, effectually overcome, and the wharf
walls, locks, sills and bridges of the St. Katherine Docks are
generally regarded as a master-piece of harbour construction.
Alluding to the rapidity with which the works were completed,
Mr. Telford says: "Seldom, indeed never within my knowledge, has there
been an instance of an undertaking; of this magnitude, in a very
confined situation, having been perfected in so short a time;....
but, as a practical engineer, responsible for the success of
difficult operations, I must be allowed to protest against such
haste, pregnant as it was, and ever will be, with risks, which, in
more instances than one, severely taxed all my experience and
skill, and dangerously involved the reputation of the directors as
well as of their engineer."
Among the remaining bridges executed by Mr. Telford, towards the
close of his professional career, may be mentioned those of
Tewkesbury and Gloucester. The former town is situated on the
Severn at its confluence with the river Avon, about eleven miles
above Gloucester. The surrounding district was rich and populous;
but being intersected by a large river, without a bridge, the
inhabitants applied to Parliament for powers to provide so
necessary a convenience. The design first proposed by a local
architect was a bridge of three arches; but Mr. Telford, when
called upon to advise the trustees, recommended that, in order to
interrupt the navigation as little as possible, the river should be
spanned by a single arch; and he submitted a design of such a
character, which was approved and subsequently erected. It was
finished and opened in April, 1826.
This is one of the largest as well as most graceful of Mr. Telford's
numerous cast iron bridges. It has a single span of 170 feet, with
a rise of only 17 feet, consisting of six ribs of about three feet
three inches deep, the spandrels being filled in with light
diagonal work. The narrow Gothic arches in the masonry of the
abutments give the bridge a very light and graceful appearance,
at the same time that they afford an enlarged passage for the high
river floods.
The bridge at Gloucester consists of one large stone arch of 150
feet span. It replaced a structure of great antiquity, of eight
arches, which had stood for about 600 years. The roadway over it
was very narrow, and the number of piers in the river and the small
dimensions of the arches offered considerable obstruction to the
navigation. To give the largest amount of waterway, and at the same
time reduce the gradient of the road over the bridge to the
greatest extent, Mr. Telford adopted the following expedient.
He made the general body of the arch an ellipse, 150 feet on the
chord-line and 35 feet rise, while the voussoirs, or external
archstones, being in the form of a segment, have the same chord,
with only 13 feet rise. "This complex form," says Mr. Telford,
"converts each side of the vault of the arch into the shape of the
entrance of a pipe, to suit the contracted passage of a fluid, thus
lessening the flat surface opposed to the current of the river
whenever the tide or upland flood rises above the springing of the
middle of the ellipse, that being at four feet above low water;
whereas the flood of 1770 rose twenty feet above low water of an
ordinary spring-tide, which, when there is no upland flood, rises
only eight or nine feet."*[1] The bridge was finished and opened in
1828.
[Image] Dean Bridge, Edinburgh.
The last structures erected after our engineer's designs were at
Edinburgh and Glasgow: his Dean Bridge at the former place, and his
Jamaica Street Bridge at the latter, being regarded as among his
most successful works. Since his employment as a journeyman mason
at the building of the houses in Princes Street, Edinburgh, the New
Town had spread in all directions. At each visit to it on his way
to or from the Caledonian Canal or the northern harbours, he had
been no less surprised than delighted at the architectural
improvements which he found going forward. A new quarter had risen
up during his lifetime, and had extended northward and westward in
long lines of magnificent buildings of freestone, until in 1829 its
further progress was checked by the deep ravine running along the
back of the New Town, in the bottom of which runs the little Water
of Leith. It was determined to throw a stone bridge across this
stream, and Telford was called upon to supply the design. The point
of crossing the valley was immediately behind Moray Place, which
stands almost upon its verge, the sides being bold, rocky, and
finely wooded. The situation was well adapted for a picturesque
structure, such as Telford was well able to supply. The depth of
the ravine to be spanned involved great height in the piers, the
roadway being 106 feet above the level of the stream. The bridge
was of four arches of 90 feet span each, and its total length 447
feet; the breadth between the parapets for the purposes of the
roadway and footpaths being 39 feet.*[2] It was completed and
opened in December, 1831.
But the most important, as it was the last, of Mr. Telford's stone
bridges was that erected across the Clyde at the Broomielaw,
Glasgow. Little more than fifty years since, the banks of the river
at that place were literally covered with broom--and hence its
name--while the stream was scarcely deep enough to float a
herring-buss. Now, the Broomielaw is a quay frequented by ships of
the largest burden, and bustling with trade and commerce. Skill and
enterprise have deepened the Clyde, dredged away its shoals, built
quays and wharves along its banks, and rendered it one of the
busiest streams in the world,
It has become a great river thoroughfare, worked by steam. On its
waters the first steamboat ever constructed for purposes of traffic
in Europe was launched by Henry Bell in 1812; and the Clyde boats
to this day enjoy the highest prestige.
The deepening of the river at the Broomielaw had led to a gradual
undermining of the foundations of the old bridge, which was
situated close to the principal landing-place. A little above it,
was an ancient overfall weir, which had also contributed to scour
away the foundations of the piers. Besides, the bridge was felt to
be narrow, inconvenient, and ill-adapted for accommodating the
immense traffic passing across the Clyde at that point. It was,
therefore, determined to take down the old structure, and Build a
new one; and Mr. Telford was called upon to supply the design.
The foundation was laid with great ceremony on the 18th of March, 1833,
and the new bridge was completed and opened on the 1st of January,
1836, rather more than a year after the engineer's death. It is a
very fine work, consisting of seven arches, segments of circles,
the central arch being 58 feet 6 inches; the span of the adjoining
arches diminishing to 57 feet 9 inches, 55 feet 6 inches, and 52
feet respectively. It is 560 feet in length, with an open waterway
of 389 feet, and its total width of carriageway and footpath is 60
feet, or wider, at the time it was built, than any river bridge in
the kingdom.
[Image] Glasgow Bridge
Like most previous engineers of eminence--like Perry, Brindley,
Smeaton, and Rennie--Mr. Telford was in the course of his life
extensively employed in the drainage of the Fen districts. He had
been jointly concerned with Mr. Rennie in carrying out the
important works of the Eau Brink Cut, and at Mr. Rennie's death he
succeeded to much of his practice as consulting engineer.
It was principally in designing and carrying out the drainage of
the North Level that Mr. Telford distinguished himself in Fen
drainage. The North Level includes all that part of the Great
Bedford Level situated between Morton's Leam and the river Welland,
comprising about 48,000 acres of land. The river Nene, which brings
down from the interior the rainfall of almost the entire county of
Northampton, flows through nearly the centre of the district.
In some places the stream is confined by embankments, in others it
flows along artificial outs, until it enters the great estuary of
the Wash, about five miles below Wisbeach. This town is situated on
another river which flows through the Level, called the Old Nene.
Below the point of junction of these rivers with the Wash, and
still more to seaward, was South Holland Sluice, through which the
waters of the South Holland Drain entered the estuary. At that
point a great mass of silt had accumulated, which tended to choke
up the mouths of the rivers further inland, rendering their
navigation difficult and precarious, and seriously interrupting the
drainage of the whole lowland district traversed by both the Old
and New Nene. Indeed the sands were accumulating at such a rate,
that the outfall of the Wisbeach River threatened to become
completely destroyed.
Such being the state of things, it was determined to take the
opinion of some eminent engineer, and Mr. Rennie was employed to
survey the district and recommend a measure for the remedy of these
great evils. He performed this service in his usually careful and
masterly manner; but as the method which he proposed, complete
though it was, would have seriously interfered with the trade of
Wisbeach, by leaving it out of the line of navigation and drainage
which he proposed to open up, the corporation of that town
determined to employ another engineer; and Mr Telford was selected
to examine and report upon the whole subject, keeping in view the
improvement of the river immediately adjacent to the town of
Wisbeach.
Mr. Telford confirmed Mr. Rennie's views to a large extent, more
especially with reference to the construction of an entirely new
outfall, by making an artificial channel from Kindersleys Cut to
Crab-Hole Eye anchorage, by which a level lower by nearly twelve
feet would be secured for the outfall waters; but he preferred
leaving the river open to the tide as high as Wisbeach, rather than
place a lock with draw-doors at Lutton Leam Sluice, as had been
proposed by Mr. Rennie. He also suggested that the acute angle at
the Horseshoe be cut off and the river deepened up to the bridge at
Wisbeach, making a new cut along the bank on the south side of the
town, which should join the river again immediately above it,
thereby converting the intermediate space, by draw-doors and the
usual contrivances, into a floating dock. Though this plan was
approved by the parties interested in the drainage, to Telford's
great mortification it was opposed by the corporation of Wisbeach,
and like so many other excellent schemes for the improvement of the
Fen districts, it eventually fell to the ground.
The cutting of a new outfall for the river Nene, however, could not
much longer be delayed without great danger to the reclaimed lands
of the North Level, which, but for some relief of the kind, must
shortly have become submerged and reduced to their original waste
condition. The subject was revived in 1822, and Mr. Telford was
again called upon, in conjunction with Sir John Rennie, whose
father had died in the preceding year, to submit a plan of a new
Nene Outfall; but it was not until the year 1827 that the necessary
Act was obtained, and then only with great difficulty and cost, in
consequence of the opposition of the town of Wisbeach. The works
consisted principally of a deep cut or canal, about six miles in
length, penetrating far through the sand banks into the deep waters
of the Wash. They were begun in 1828, and brought to completion in
1830, with the most satisfactory results. A greatly improved
outfall was secured by thus carrying. the mouths of the rivers out
to sea, and the drainage of the important agricultural districts
through which the Nene flows was greatly benefited; while at the
same time nearly 6000 acres of valuable corn-growing land were
added to the county of Lincoln.
But the opening of the Nene Outfall was only the first of a series
of improvements which eventually included the whole of the valuable
lands of the North Level, in the district situated between the Nene
and the Welland. The opening at Gunthorpe Sluice, which was the
outfall for the waters of the Holland Drain, was not less than
eleven feet three inches above low water at Crab-Hole; and it was
therefore obvious that by lowering this opening a vastly improved
drainage of the whole of the level district, extending from twenty
to thirty miles inland, for which that sluice was the artificial
outlet, would immediately be secured. Urged by Mr. Telford, an Act
for the purpose of carrying out the requisite improvement was
obtained in 1830, and the excavations having been begun shortly
after, were completed in 1834.
A new cut was made from Clow's Cross to Gunthorpe Sluice, in place
of the winding course of the old Shire Drain; besides which, a
bridge was erected at Cross Keys, or Sutton Wash, and an embankment
was made across the Salt Marshes, forming a high road, which, with
the bridges previously erected at Fossdyke and Lynn, effectually
connected the counties of Norfolk and Lincoln. The result of the
improved outfall was what the engineer had predicted. A thorough
natural drainage was secured for an extensive district, embracing
nearly a hundred thousand acres of fertile land, which had before
been very ineffectually though expensively cleared of the surplus
water by means of windmills and steam-engines. The productiveness
of the soil was greatly increased, and the health and comfort of
the inhabitants promoted to an extent that surpassed all previous
expectation.
The whole of the new cuts were easily navigable, being from 140 to
200 feet wide at bottom, whereas the old outlets had been variable
and were often choked with shifting sand. The district was thus
effectually opened up for navigation, and a convenient transit
afforded for coals and other articles of consumption. Wisbeach
became accessible to vessels of much larger burden, and in the
course of a few years after the construction of the Nene Outfall,
the trade of the port had more than doubled. Mr. Telford himself,
towards the close of his life, spoke with natural pride of the
improvements which he had thus been in so great a measure
instrumental in carrying out, and which had so materially promoted
the comfort, prosperity, and welfare of a very extensive
district.*[3]
We may mention, as a remarkable effect of the opening of the new
outfall, that in a few hours the lowering of the waters was felt
throughout the whole of the Fen level. The sluggish and stagnant
drains, cuts, and leams in far distant places, began actually to
flow; and the sensation created was such, that at Thorney, near
Peterborough, some fifteen miles from the sea, the intelligence
penetrated even to the congregation then sitting in church--for it
was Sunday morning--that "the waters were running!" when
immediately the whole flocked out, parson and all, to see the great
sight, and acknowledge the blessings of science. A humble Fen poet
of the last century thus quaintly predicted the moral results
likely to arise from the improved drainage of his native district:-
"With a change of elements suddenly
There shall a change of men and manners be;
Hearts thick and tough as hides shall feel remorse,
And souls of sedge shall understand discourse;
New hands shall learn to work, forget to steal,
New legs shall go to church, new knees to kneel."
The prophecy has indeed been fulfilled. The barbarous race of
Fen-men has disappeared before the skill of the engineer. As the
land has been drained, the half-starved fowlers and fen-roamers
have subsided into the ranks of steady industry--become farmers,
traders, and labourers. The plough has passed over the bed of
Holland Fen, and the agriculturist reaps his increase more than a
hundred fold.. Wide watery wastes, formerly abounding in fish,
are now covered with waving crops of corn every summer. Sheep graze
on the dry bottom of Whittlesea Mere, and kine low where not many
years since the silence of the waste was only disturbed by the
croaking of frogs and the screaming of wild fowl. All this has been
the result of the science of the engineer, the enterprise of the
landowner, and the industry of our peaceful army of skilled
labourers.*[4]
Footnotes for Chapter XIII.
*[1] Telford's Life, p261
*[2] The piers are built internally with hollow compartments, as at
the Menai Bridge, the side walls being 3 feet thick and the cross
walls 2 feet. Projecting from the piers and abutments are pilasters
of solid masonry. The main arches have their springing 70 feet from
the foundations and rise 30 feet; and at 20 feet higher, other
arches, of 96 feet span and 10 feet rise, are constructed; the face
of these, projecting before the main arches and spandrels,
producing a distinct external soffit of 5 feet in breadth.
This, with the peculiar piers, constitutes the principal distinctive
feature in the, bridge.
*[3] "The Nene Outfall channel," says Mr. Tycho Wing,
"was projected by the late Mr. Rennie in 1814, and executed jointly
by Mr. Telford and the present Sir John Rennie. But the scheme of
the North Level Drainage was eminently the work of Mr. Telford,
and was undertaken upon his advice and responsibility, when only a
few persons engaged in the Nene Outfall believed that the latter
could be made, or if made, that it could be maintained. Mr. Telford
distinguished himself by his foresight and judicious counsels at
the most critical periods of that great measure, by his unfailing
confidence in its success, and by the boldness and sagacity which
prompted him to advise the making of the North Level drainage, in
full expectation of the results for the sake of which the Nene
Outfall was undertaken, and which are now realised to the extent of
the most sanguine hopes."
*[4] Now that the land actually won has been made so richly
productive, the engineer is at work with magnificent schemes of
reclamation of lands at present submerged by the sea. The Norfolk
Estuary Company have a scheme for reclaiming 50,000 acres; the
Lincolnshire Estuary Company, 30,000 acres; and the Victoria Level
Company, 150,000 acres--all from the estuary of the Wash. By the
process called warping, the land is steadily advancing upon the
ocean, and before many years have passed, thousands of acres of the
Victoria Level will have been reclaimed for purposes of
agriculture.