The Thames and Severn Canal

A Report

By W F Alderton

It is believed that this report was written in 1959-60 when W F Alderton was the Assistant County Council Surveyor in charge of the canal.

Thames and Severn Canal

By an Act of Parliament dated 1783 "The Company of Proprietors of the Thames & Severn Canal Navigation" was empowered to make and maintain a navigable canal from the River Thames at Lechlade to join with the Stroudwater Canal at Stroud.

In 1791, 1793 and 18O9 there were further Acts of Parliament to enable the Company to raise more money. The total amount raised by the four Acts amounted to £455,000.

The scheme was first projected by Mr. Brindley but at his decease Mr. Whitworth was appointed his successor, by whom the work was executed.

The total length of the Canal is thirty and one eighths miles; from Stroud to Inglesham (Lechlade) is twenty eight and three quarter miles and the branch to Cirencester is one and three eighths miles. It was designed to take boats carrying 30 tons between the Severn and Thames.

From Stroud to Sapperton, a distance of seven and three eighths miles, there is a rise of 241 feet with 28 locks. From there the summit pound continues for eight and one eighth miles to Coates and passes through the Sapperton Tunnel. From Coates to the Thames at Inglesham is a distance of thirteen and one quarter miles and has a fall of 128 feet with 16 locks.

The celebrated Sapperton Tunnel is two and a half miles in length; the arch is 15 feet wide and is a maximum of 250 feet below the highest point on the hill, which is of hard rock some of it so solid as to need no masonry arch to support it; the other parts are arched above and have inverted arches in the bottom.

From this it will be seen that the engineering difficulties were fairly heavy, particularly when it is realised that there was not much machinery available in those days, and it all had to be carried out by manual labour and horses and carts.

On the 19th November 1789 the first boat passed from the Severn to the Thames, but the Canal does not appear to have been officially opened until 1799.  It was worked successfully for many years, and the maximum tonnage of 89,271 was in 1841.

In that year railway competition began to reduce the traffic; and gradually the Thames, between Lechlade and Oxford, became unnavigable and the through traffic on the Canal became impracticable; lessened receipts led to the neglect of necessary repairs and in 1881 the traffic was reduced to 43,811 tons.

The condition of the Canal became worse, until in 1893, when it had fallen under the control of the Great Western Railway, the length from Lechlade to Chalford was formally closed. This led to an active movement in the district for its restoration, which culminated in the passing of the Thames & Severn Canal Trust Act of 1895 vesting the Canal in a Trust representing the Navigations, County Council and other public bodies.

In 1894 the Thames Conservancy had been placed on a new footing which enabled it to restore the navigation of the Upper Thames.

The Canal Trust expended nearly £15,000 on the restoration of the Canal, but this proved insufficient owing to serious defects on the summit level and shortage of water.  The Trust exhausted its borrowing powers, and in 1901 the Canal was transferred by Provisional Order to the Gloucestershire County Council who were authorized to borrow a further sum for its restoration.  A considerable amount was spent on provision of a greatly increased supply of water to the upper levels, and the first boat on this restored Canal passed over the summit on the 12th March, 1904, but the freights carried did not come up to expectations, and the expenditure exceeded the income.

In 1908 the Gloucestershire County Council appointed a Committee to consider the policy to be pursued and it was suggested that the Canal could be run more cheaply and efficiently by the Thames Navigation who had more experience and a competent staff, but nothing came of this.

A consulting Engineer, Mr G W Keeling, M.InstCE was called in to report.  After a careful survey of the conditions a full report was made in February 1909, and without going into any details the following is a short extract which sums up the whole situation:

'I am of the opinion that it will cost quite £100 per mile per annum (£3,000 pa) for management and maintenance to keep the Canal open in a sufficiently efficient condition for traffic.  As you are aware, the difficulty of the navigation is the want of an adequate water supply by gravitation to the summit, involving pumping, which in itself is a serious expense to a Navigation with little traffic.'

This more or less finished the upper reaches, but the four miles from Stroud to Chalford was still working.

In 1924 another Consulting Engineer, Mr J S Alford, M.InstCE was called in to make a report preparatory to the abandonment of the Canal.  Mr Alford presented a lengthy report in February 1925 in which he details all the assets and liabilities of the Canal, and makes particular mention of the length from Daneway to Stroud, where the Canal carries flood water in times of storm.  The suggestion he made was that a low weir be placed at each lock and the gates opened or removed.

There were many objections to the abandonment, which were successfully overcome, and on May 10th 1927 the Minister of Transport signed an Order for the abandonment of that part of the Canal from Lechlade up to but exclusive of Whitehall Bridge at Frampton Mansell.

This still left the length from Whithall to Stroud to be dealt with, and the Thames & Severn Canal Committee of the County Council were considering the future of this length, and quoting from Committee Minutes -

27th October 1930 - Mr Alford recommends keeping the length from Chalford to Stroud open as a flood water channel.

16th March 1931 - The County Council are prepared to keep this length open to pass flood water by constructing small weirs at each lock.

22 May 1933 - Committee found they could not carry out this work and as this length of Canal was 'main river' on the Catchment Board maps, they requested that this be deleted.  This was done.

9th June 1933 - The Minister of Transport signed an Order authorizing the County Council to abandon all that part of the Canal which remains vested in them.

7th July 1935 - The Clerk reported to the Committee that the County Council had decided to keep the length from Chalford to Stroud open for drainage purposes.

30th September 1935 - The Highways Committee took over from the Thames & Severn Canal Committee, and the County Surveyor became the Engineer in charge.

The Clerk's Department has been busy since 1927 disposing of land and property vested in the Canal, and as they had done this all themselves and made their own plans without a master plan to show what was still unsold, the first job was to find out what the County Council still owned.

There were no plans of the Canal, either showing the land and property or any engineering plans, so everything had to be found out by inspection and information gained from adjoining owners or from old canal employees.  After 25 years' work, there is now a plan showing, as far as is known, what the County owns, but the engineering details are still non-existent; each problem has to be dealt with as it crops up.

The first thing that had to be realized was that Canal Engineers used timbers for everything and the tradesmen in this were Millwrights, which is a dying trade, but the County are fortunate in having one of these men still left in their employ.  All sluices and penstocks are of timber, and even the culverts under the Canal, where a stream crosses are large elm boxes - the largest known being eight feet by four feet in cross section - and as these have been in existence for about 170 years it is necessary to watch them, as on one occasion a horse fell through the one at The Bourne; it was partially replaced with concrete.

In 1935 there were 92 separate easements, varying from 6d (2.5p) to £106 per annum some of which had been in existence for over 100 years, and in many cases the details are not known, and have to be searched for if required.   These have been added to, and many have been relinquished as property is pulled down or new owners do not require the easement.

There were many sections where the old 'Tythe Rent' still existed and these have been redeemed as they crop up, often in the most unexpected places.

The boundary of the Canal for long lengths is undefined, and often, where sale of adjoining property takes place, an affidavit has to be sworn to establish the boundary for the purpose of preparation of deeds, and in one case where there were two properties which had formerly been part of the Canal and never had a dividing fence, the Trustees, on the death of one owner, asked the Surveyor's Department to determine the boundary; this was done to the complete satisfaction of both parties.

A Canal is like a railway, and the proprietors are responsible for all fences where they exist, unless there is evidence to the contrary.  Where there are no fences, each lateral fence has to have a gate across the tow-path to prevent cattle straying from one owner to another.

In 1924 an Agreement had been made with the Stroud Valley Millowners Association and The Stroud Water Company whereby the County Council (as owners of the Canal) were at liberty to take water from several specified sources, for the purpose of Navigation, between the hours of one o'clock in the afternoon on Sundays, and in addition for not more than six hours for two nights per week, between five o'clock in the afternoon and one o'clock on the following morning, on giving two hours' notice to the Secretary of the Millowners Association.

The Stroud Water Company were forbidden to abstract, from any springs in the Valley, any greater quantity of water in any day of 24 hours than 750,000 gallons.  This quantity has since been increased by further agreements.

This agreement is still in existence, but as the Mills have nearly all ceased to use water power, it is not strictly enforced, and as the Canal is no longer open to navigation the water is not required except in dry periods in the summer, when water has to be taken to the Canal to comply with and agreement made in 1932 with the Great Western Railway, in which water has to be kept up in the Brimscombe and Stroud Pounds to enable the Railway to pump water to their Water Cranes, for which they pay the County £106 per annum.  It is very difficult to carry out this obligation in times of drought, as the Stroud Pound is nearly three miles downstream of the nearest intake, and the water tends to get lost en route, but by careful management, and sometimes a polite conversation with the Railway Foreman, any shortage so far has been overcome.

This Agreement also included that the Council should convey to the Railway Company the sites of the bridges carrying the railway over the Canal, together with such further portions of the Canal, on both sides of the bridges, as the Company may require, to enable them to remove the bridges, and substitute solid embankments with a conduit through to allow the flood water to pass.

These sites, of which there are three, were conveyed to the Transport Commission in 1946, and one of them has already been filled in, with a 72-inch culvert through.  A further one will be done this year.  The lines, levels and sizes of these culverts have to be agreed with the Commission, when it is known what their proposals are, and on the one to be done this year, the Public Footpath has to be diverted across the Canal by means of a subway, and the new main sewer recently laid had to be put in at lower levels to clear the subway.

The main sewer for the Chalford Valley has recently been laid, and rather than have very deep trenches cut all along the main road (A 419) long lengths have been laid in the bed of the Canal.  All the lines and levels of this had to be agreed and a watch kept on the work as it proceeded, as there are weirs and sluices on the Canal that have to be kept in working order.

The Gas Main and Power Cable are both in the tow-path for long lengths and agreements have to be entered into, with specifications as to means of passing through or over the weirs and penstock boxes.

There are numerous agreements with the Post Office, and Electricity Board for wires over, and poles on, the Canal, and the usual small easements with adjoining owners for pipes, windows and doors, all of which have to be dealt with.

There are two cottages and a workshop at Brimscombe Port, which have recently been put on the new sewer and given proper sanitary arrangements and modernised with bathrooms etc.  These are occupied by Canal employees who have to be on the site in case of flood.

A balance of water has to be kept between the River Frome and the Canal, as neither can pass all the water when there is a storm over the whole catchment area, which is roughly 30 square miles and extends as far a Birdlip.  The slopes of the valley are steep, and the run-off is very fast and even in summer, after a heavy thunderstorm, the water can rise several inches in an hour.

The Canal men are centered at Brimscombe, where the River and Canal are on each side of their cottages, so they can watch them and see if either is rising to danger level, and pass water from one to the other, as in their judgment will get it to Wallbridge (Stroud) without flooding property en route.

This is a skilled job and cannot be learned, except by experience, and since 1935 there has been no serious flooding in the Chalford Valley except in the winter of 1947 when the whole area was frost bound, followed by a heavy fall of snow then a rapid thaw and heavy rain.  It became impossible to control the water and the Canal bank burst just below Bowbridge where the River passes under the Canal, with the result the whole flood was in the River from there on, and Wallbridge Mill and the cottages around it were badly flooded.

Up to this time the pounds were kept nearly full for amenities' sake, but now the bottom paddles have been raised in all but four pounds, with the result that the water flows through an empty pound, but the danger here is that the paddles become choked with debris, which is difficult to remove, as the water immediately begins to rise and the stoppage cannot be reached.  Over the years, with the pounds dry, the elm boards on the oak frames of the gates have split and become rotten, and the gate has gradually gone into decay, with the result that water now runs over the sill of the gate in times of flood, or if the paddle becomes choked.  The Brimscombe and Stroud pounds, where the water has to be kept up, have both had concrete dams built across them and the gates removed.

That is the condition the Canal is in at present, but with empty pounds vegetation grows very rapidly and willows and other fairly large trees soon begin to grow, and as silt and detritus is brought down on the flood, it is quite impossible for an artificial dam to be formed, and unless these are seen and broken before they become too solid a pound can become full and in this case there is no paddle that can be raised to release the flood, as there is at each set of gates.

Several lengths of the Canal have now been sold to adjoining owners for extension to the factories but in each case a proviso has been made that before it is filled in, a twin 48-inch tube must be laid to pass the flood.  The reason for such large tubes is that each pound is level from gate to gate and therefore these tubes can be given no fall, and the only way water can flow through them is by piling up at the upstream end and making its own gradient.  The result of this is that silt gradually collects in the tubes and unless this is cleaned out from time to time, a serious obstruction can occur.  A man can work in a 48-inch tube and it would be most unlikely that both tubes became blocked on the same length at the same time, and in normal times the water would be passed down one tube while the other was being cleared.

The whole of the flood water, both in the Canal and River Frome, gets to Wallbridge in Stroud where the Slad Stream enters the Canal.  If the Slad Valley is in flood at the same time as the Chalford Valley, the column of water in the Canal is too great to be passed into the River by the culvert under the Brewery premises and trunk road (A46) to the upstream side of the river bridge on the A46 without flooding the trunk road and surrounding property.  This frequently happened prior to 1935 but never since, as part of the flood has been allowed to go over the bottom gates of the Thames & Severn Canal into the Stroudwater Canal and this is now being dealt with by the Severn River Board, who have declared as 'main stream' the length of Stroudwater from Ebley to Wallbridge, and the Thames & Severn Canal from the Junction to the Slad Stream.

The River Board are dredging and stone facing the banks on this length and although this work is not yet completed it has been a great success and passed each flood so far and prevented previous serious flooding of the Mills and Factories between Wallbridge and Ebley; so long as the water in the upper reaches of the Thames & Severn Canal can be got to Wallbridge it will now be passed on without causing any trouble.

It may be asked why the Canal has to pass flood water and why it should not all go in the River, so perhaps a look back into the past may not come amiss.

There has always been a River, but it was in the form of a series of swamps all down the valley, and a flood simply raised the level of these a foot or two with no serious harm to anybody.  In the 17th century the Huguenots came over and built the Mills and cleaned out the swamps and made them into mill ponds, and trained the river into a proper channel.  It is reasonable to assume that they also kept it clear and so had some control of the floods when they came.

Late in the 18th century the Canal was built and there must have been a lot of bargaining with the Millowners regarding 'riparian' rights, and so most of the side streams are passed under Canal in elm culverts, sometimes with a storm water overflow into the Canal.  In addition there is the Agreement, mentioned before, whereby the Canal took water at specified times.

The coming of the Canal must have brought new works and mills into the Valley and a road was built, as previously the track that was there only went as far a Brimscombe.  The Canal is between the road and the river, so most of the road drains go into the Canal.  Side roads, more houses and factories follow, all passing water into the Canal.  The Canal authority were only too pleased to accept this extra water as they were desperately short at times.

Next came the Great Western Railway, which crosses the Canal in six places, one of which is where the Railway tunnel crossed the site of the highway and a new road built alongside.  This brought more streets, factories and houses with the extra run-off water, perhaps half of which enters the Canal.

Everything worked very well so long as the Canal had employees to pass the flood down from pound to pound by working the penstocks as necessary.  The Millowners did the same on the river, and for their own and everybody else's sake it can be assumed the river was kept cleaned out and the floods passed without too much inconvenience.

This has now all changed: the Mills no longer use water power, and most of the mill ponds are silted up and cease to act a reservoirs.  The Canal is no longer worked, with the result there is nobody to control the flood when it comes, except the Canal employees, one of whom has been on the Canal all his life and his father before him.

All this has happened in the past, the roads, factories and houses have been built with conditions as they were found at the time, and to change it and try to put all the water in the River without some very extensive and expensive alterations would be disastrous, as a lot of the Mills are built over the River and their weirs and sluices are not designed to take the whole of the flood.

So long as the Canal has to deal with part of the flood in the Valley, it will need constant maintenance, as it is well above the adjoining land for long lengths, and the banks have to be kept in order as tree roots and rodents are constantly breaking them down.  In three places the river passes under the Canal and two of these are always danger spots in flood time.

The tow-path has now been declared a public footpath and the weeds are cut and the surface kept in as reasonable a condition as possible.  The boundary is often undefined, and unless there is evidence to the contrary the tow-path is nine foot wide.

No engineering plans of the Canal are in existence, but from observations and experience over the years it has been found that the overflow weirs are in the form of round wells, into which the water falls to the lower level and then carried to the next pound in a brick culvert; the bottom paddles are of elm shutters sliding in a wooden frame and have a long wrought iron arm with a ratchet on top which is worked from ground level.

There are compensating weirs in many pounds, the outfalls of which are often difficult to find, and sometimes were a means of flushing the sanitary arrangements in an adjoining mill.

Several of the locks were shortened in an endeavour to save water; this was done by arching over part of the bottom of the lock and moving the top gates forward on to this arch.

As the pounds are now nearly all empty, the details of these weirs and paddles have little importance, and as each one is slightly different from the last no precise details can be given.

There are innumerable springs and surface water drains entering the Canal and now the sewer is laid in the valley, the water should be clean for the whole length.

The day to day maintenance and repair (there is often wanton damage to bridge parapets and fences) keep three men fully occupied, and on large jobs extra men have to be brought in from the Division, as one of the greatest difficulties is the inaccessibility of the work and materials have to be got to the site in hand trucks and barrows, which adds to the cost.

Much of this report is a collection of facts gleaned from old correspondence, Committee Minutes, and the two Statements in 1909 of Sir John Dorrington and Viscount St Aldwyn, together with over 25 years' experience of running the Canal, but to say it was complete would be very presumptuous, as something new or unusual is found nearly every time a visit is made to the Canal.

This page was added by Iris Capps on 13/09/2009.

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