Rivers, Streams & Drainage

3. County Council Services

Rivers, Streams & Drainage

THE rapid urbanization of the County at the end of the last century outstripped the provisions made by the local authorities for the disposal of sewage and consequently many of the rivers and streams became so seriously polluted as to cause great public concern. In 1898, therefore, the County Council obtained powers, firstly, to take proceedings against persons suspected of polluting rivers and, secondly, to enable cleansing to be carried out and the execution of such works as might be necessary to maintain an unobstructed flow of water. In taking this step, Middlesex became the first county council to take over the control of its water-courses.

Foreseeing the development of the County and the spoliation of the natural beauty of the riverside by such development, the County Council took steps (later justified by the Abercrombie report) to acquire lands in the immediate vicinity of the streams and rivers for the purpose of providing” riverside walks” and open-space facilities. Powers were also obtained to acquire lands compulsorily for the purpose of carrying out improvements.

The County Council maintained all the important water-courses in Middlesex until the passing of the Land Drainage Act, 1930, the purpose of which was to overcome conditions prevailing in certain parts of the country where the neglect of the water-courses had resulted in serious deterioration of agricultural land.

After the passing of that Act all the water-courses falling within the catchment areas of the Rivers Thames and Lee passed from the control of the County Council to that of the Thames and Lee Catchment Boards respectively.

The County Council retained control of approximately 68.5 miles of watercourses in the catchment areas of the Rivers Brent and Crane, which discharge into the Thames below Teddington Lock, the highest point reached by the tide.

The passing of the Rivers (Prevention of Pollution) Act, 1951, gave statutory powers to the County Council equal to those of a River Board in respect of pollution only, and this should materially assist in restoring the water-courses to a higher standard of cleanliness than they have known for very many years.

Artificial Rivers

There are three artificial rivers in the County—namely, the Longford River, the Duke of Northumberland’s River and the New River. The Longford River (which has also been known as The King’s River, The Queen’s River, The New Cut, Hampton Court Cut, Wolsey’s River, and Cardinal’s River) was constructed by order of Charles I to supply the ornamental waters of Hampton Court Palace and grounds. It was cut from the River Colne at Harmondsworth and passes through the parishes of Stanwell, Bedfont, Feltham and Hampton to the Palace at Hampton Court. The Duke of Northumberland’s River, which flows into the Thames at Isleworth, was constructed in the reign of Henry VII, at his own expense, to serve the Abbey of Syon with water to drive a mill at Twickenham, and was later extended to the Abbey’s other mill at Isleworth.

The mills on the river, after many years of usefulness, have now ceased to exist—the last of these landmarks, “Kidd’s Mill “, having been demolished in 1940, and the river therefore no longer serves the purpose for which it was originally intended. In view of the inconvenience of having a privately-owned river running across the County, over which roads, mains and cables could pass only at the will of a private owner or by obtaining statutory powers, and in view of the desirability of the County Council having supervision of the flow of water in times of flood, the County Council decided that the river should be publicly owned and controlled. Under the Council’s Act of 1930, therefore, the necessary authority was obtained to acquire the river, which is now the freehold property of the County Council.

The New River was constructed under the direction of Sir Hugh Myddelton in the reign of James I to bring drinking water from the wells at Amwell and Shadwell in Hertfordshire to Clerkenwell in London. This still forms an important link in the system of water supply for London.

Navigable Waterways

To-day there are three navigable waterways in or adjoining Middlesex—the River Thames, the Lee Navigation and the Grand Union Canal.

The River Lee Navigation connects the River Thames at London Docks with Hertfordshire and serves the eastern part of the County.

The Grand Union Canal leaves the River Thames at Brentford, incorporating 2½ miles of the River Brent, proceeds towards Uxbridge and thence to the midlands, and at Hayes there is a connection by way of the Paddington arm and the Regent’s Canal to the London Docks.

Modern canal barges driven by internal combustion engines can travel from Birmingham to London in about 50 hours, and the canal has been improved so that barges capable of loading directly from or into sea-going ships can be taken throughout the system. The total goods traffic along these canals to and from Middlesex is 700,000 tons per year—including a considerable quantity of traffic from the Warwickshire collieries, whilst some 1,120,000 tons per year of commodities are transported to and from the County on the River Thames.

The Welsh Harp, or Brent Reservoir, is a well-known feature of the County, and was originally constructed to provide a supply of water to the Regent’s Canal.

Natural Streams and Drainage

Before the County became urbanized with the building of roads, houses and factories, rainfall on arable and pasture lands took a considerable time to reach the rivers, since it had to percolate through the soil to the field ditches and thence to the main stream. Low-lying areas adjacent to the rivers became inundated in storm periods, and therefore helped to diminish the flow of surface water. Building development made large areas impervious to rain which had to be taken by surface-water drains directly to the rivers, and this resulted in a large proportion of the rain-water reaching the rivers very soon after it had fallen, causing a sudden rise in the level of the river and a greater tendency to flooding of the low-lying areas. Where these low-lying areas were built-up, undesirable flooding occurred in other places, as the old water-courses became inadequate to cope with the flow of water under new conditions. The County Council therefore directed that an estimate be prepared of the ultimate requirements of each river when its catchment area was fully developed. It is necessary to record as far as possible data relating to conditions which affect the flow, so that reasonable provision may be made to prevent flooding. For this purpose” rain gauges” which register the amount and intensity of rainfall are installed in various parts of the County, and automatic flow meters recording the volume of water passing down them are placed in the streams. As a result of the information collected, much useful work has been done, and is still in progress. At the present time surveys are being made of the remaining sections of the streams under the Council’s control with a view to their improvement, and to the provision of movable weirs by means of which the water may be controlled during flood periods.

Staff constantly patrol the streams, performing any works necessary to ensure an unobstructed flow of water. In built-up districts, however, particularly where the streams run by gardens of houses, much time, labour and money is expended in clearing away rubbish which is thoughtlessly thrown into them in spite of the fact that the County Council has power to take proceedings against people found committing this nuisance.

County Main Drainage
The Two Drainage Areas

WEST MIDDLESEX MAIN DRAINAGE

Of all the public services afforded to civilized communities none is more essential than the provision of an abundant supply of water. Under modern conditions, water is not merely required to enable man to live but is used much more extensively to carry away all kinds of dirt and waste matter, not only from baths, sinks and lavatories in the houses of the people but also from industrial processes of every description. So universal has the use of water become that whereas a man needs only a few pints a day for drinking, he uses on an average no less than 50 gallons a day for other purposes.

When this used water leaves houses and factories, it is known as sewage, and is much too impure to be allowed to flow into the nearest stream or river, as it used to do in the past, without first being purified. For this purpose it is taken by drains from each building into sewers along which it flows to the sewage purification works where it is treated by special processes. Sewers are generally laid beneath roads, but they may sometimes run across Country or even beneath houses. They are arranged in a similar manner to a river and its tributaries, commencing as small pipes of about 9 inches in diameter and becoming steadily larger in size as they join up with other sewers, until they may finally reach the size of the tube for an underground railway.

The Need for Co-operation

Until 1935 all the work of maintaining sewers and of purifying sewage in Middlesex was carried out by the local authority for each particular district.
Not many years ago a large part of the County, particularly in the west, was predominantly rural in character. The comparatively small towns which then existed were separated by stretches of open country. After the first world war the enormous amount of building development taking place everywhere in the County had been rapidly transforming the district into one vast built-up area. As long ago as 1928 the population of West Middlesex had increased to such an extent that the local authorities were finding difficulty in extending their sewers and in enlarging their sewage works to keep pace with the ever-increasing volume of sewage to be dealt with. It then became increasingly obvious that the difficulties of the area as a whole could not be overcome without some form of co-operation between the various districts, and the County Council undertook the task of considering the whole question.
As a result of this, it was finally agreed by the local authorities that the County Council should obtain powers, under a special Act of Parliament, to make provision for the main drainage and the purification of sewage from an area embracing almost the whole of the western section of the County, known as the “West Middlesex sewerage district “. This district, which has a total area of about 16o square miles—that is to say, an area about 35 per cent, greater than that of the County of London—includes seven boroughs and eight urban districts, which were formerly served by no less than twenty-eight separate local sewage works.

Scope of the Works

The new scheme, embodying one of the largest purification works in the world, was designed to be able to serve an ultimate population of 2,000,000. The construction work, carried out between 1931 and 1935 at a cost of £5,500,000, included the building of 70 miles of main sewers, ranging from about 2 feet to 12 feet 9 inches in diameter, to link up the existing systems of local sewers with a new purification works at Mogden, Isleworth. After the diversion of sewage into the new system early in 1936, all the twenty-eight old works, covering a total area of about I 000 acres in various parts of the County, were closed down.

The sewage from the whole of the district, from as far as Hendon and Mill Hill in the north, Uxbridge and Staines in the west, Sunbury and Twickenham in the south, and Ealing and Chiswick in the east, is drained by gravitation along the main sewers to the new purification works, some of it having travelled nearly 20 miles. Two-thirds of the total flow reaches the works in the high level sewers at about ground-level, but the remainder arrives by the low-level sewers at a considerable depth below the surface, and this has to be lifted about 50 feet by pumping before it passes forward with the high-level sewage for treatment.

Contrary to general conception, the amount of polluting matter in sewage is extremely small, being normally only about one part of solid matter to 2000 parts of water by weight. Yet the combined liquid as it arrives at the purification works is in a highly complicated state, and many decades have been occupied in evolving the processes at present in use for separating the impurities from the liquid and for transforming the separated sludge into a harmless condition. The removal of sand, grit and heavy solid matter is a comparatively easy task and is carried out by means of settlement in sedimentation tanks of various kinds. For the more difficult work of purification of fine suspended matter and matter in solution, bacterial processes are used.

The Use of Bacteria

Bacteria are microscopic organisms, so tiny that it would take 25,000 of them placed side by side to make up 1 inch. A thimbleful of sewage can contain perhaps 10,000,000 of these small living cells and, by giving them suitable conditions, they will bring about the most extraordinary changes in the physical and chemical properties of the materials to be dealt with. By their assistance the sewage is converted into a clear, sparkling liquid, which is then discharged into the River Thames at Isleworth Alt. The volume of sewage treated in this way in dry weather is about 70,000,000 gallons a day, but in wet weather the flow may reach a rate of over 450,000,000 gallons per day.

The impurities are removed from the sewage in a liquid form, known as sludge, of which 750,000 tons per annum have to be dealt with. Here again bacterial energy is used to transform the sludge into a completely inoffensive form, which can be dried without nuisance. During this process a gas is given off, consisting largely of methane, which is used for driving gas engines, propelling works lorries and heating boilers. The entire power requirements of the purification works are provided from this sludge gas, of which over 1,250,000 cubic feet per day is produced. Thus, it is interesting to reflect that in addition to purifying completely the whole of the sewage flow, the sludge at Mogden is made to remove itself from the sedimentation tanks, pump itself into the gas tanks, heat itself to about 85° F. and again, at a later stage, to remove itself 7 miles to the Perry Oaks Works at Harmondsworth for final disposal. It is harnessed to lift the sewage at the main pump4ng-station, to operate sewage plant and pumps of all kinds, travelling cranes and workshop machinery; it provides lighting and heating, charges batteries, cleans floors in buildings, operates synchronized clocks and even carries visitors in lifts!

The present population served by the scheme is about 1,350,000; before the second world war, the annual increase of people in the drainage district had been over 50,000 for ten years in succession, but, because of the need to restrict the growth of the Greater London area, building development on such a scale will never recur. In spite of the immense amount of work involved in constructing and operating a scheme of this kind, its total cost to the citizens of the district works out at less than twopence per week per head, which can only be regarded as remarkably good value for the money expended.

A general review of the activities of the whole undertaking has been prepared in the form of a documentary film entitled “Taken for Granted “. This has been made available for exhibition for educational and scientific purposes not only in Britain but in many other countries throughout the world.

EAST MIDDLESEX MAIN DRAINAGE

The main sewerage undertaking for the western part of the County having been successfully inaugurated, the County Council turned its attention to East Middlesex and was granted Parliamentary powers in 1938 for the construction of the necessary works.

The outbreak of war in 1939 held up the progress of the scheme for the time being. The proposal, briefly, is that the sewage from the Boroughs of Edmonton, Finchley, Southgate, Tottenham, Wood Green and part of Hornsey, and from the Urban Districts of Enfield and Friern Barnet, will be drained to large new purification works on the site of the present Deephams Works in East Edmonton. The scheme will also take in the sewage from the Borough of Chingford and the Urban District of Waltham Holy Cross in Essex and from the Urban Districts of Cheshunt, East Barnet and Barnet (excepting Rowley Parish) and part of Hatfield Rural District in Hertfordshire.

The drainage area will thus comprise nearly 100 square miles, with a probable ultimate population of 900,000 persons. The volume of sewage requiring treatment is estimated at between 36,000,000 gallons per day in dry weather and 216,000,000 in wet weather. Eleven existing sewage works will be superseded, and a total area of 500 acres of land thus freed for other use.

About 30 miles of main sewers, some as large as 7 to 8 feet in diameter, will be necessary to take the sewage to Deephams and in the course of construction some miles of tunnelling will be driven below ground, leaving little surface evidence of the work.

From the larger part of the area the sewage will gravitate to the purification works but, as in the West Middlesex scheme, there will be low-level sewers serving part of the area and the sewage from these will have to be pumped up about 45 feet for treatment at the works.

The methane gas produced from the sludge will provide motive power for the operation of the works and the residual dried sludge will find a ready market amongst agriculturists for fertilization purposes.

The Deephams Works are situated close to the River Lee, into which the purified effluent of a very high standard will be discharged.