THE GREAT STINK

'Sewer' is said to be old English for 'Seaward' - and, if so, therein lies the whole problem!
'Sewer' is also said to be from the old French 'Essouier' - 'to drain'.
'Sewage' is the biological problem.
'Sewerage' is the hardware intended to cope with it!

1357: King Edward III -

... dung and other filth that had a cumulated in divers(e) places upon the banks of the river ... and fumes and other abominable stenches arising therefrom ...

1361: Butchers were forbidden from throwing the entrails of slaughtered animals into the Thames - 'it caused sickness amongst those dwelling in the city'.
1535: Henry VIII made the casting of any refuse into the river an offence.

1632: John Taylor, the Water Poet -

Dead Hogges, Dogges, Cats and well flayed Carryon Horses
Their noysome Corpses soyled the Waters Courses;
Both Swines and Stable dunge, Beast-guts and Garbage,
Street-dust, with Gardners weeds and Rotten Herbage.
And from those Waters filthy putrifaction,
Our meat and drink were made, which bred infection.

1662: Enactment of Oath for Commissioners of Sewers, Grey's Inn -

Ye shall swear that you, to your cunning, wit and power, shall truly and indifferently execute the authority given you by this COMMISSION OF SEWERS, without any favour, corruption, dread or malice to be borne to any manner of person or persons.
And as the case shall require, ye shall consent and endeavour yourself for your part to the best of your knowledge to the making of such wholesome, just, equal and indifferent laws or ordinances as shall be made and devised by the most discreet and indifferent number of your fellows being in commission with you for the due redress, reformation and amendment of all and every such things as are contained and specified in said Commission.
The same laws and ordinances to your cunning wit and power, ye shall cause to be put to due execution without favour, need, dread, or malice of affection as God so help you and all Saints.

1710: Jonathan Swift in The Tatler -

Now from all parts the swelling kennels flow,
And bear their trophies with them as they go:
Filth of all hues and colours seem to tell
What street they sail'd from, by their sight and smell ...
 
Sweepings from butchers' stalls, dung, guts and blood,
Drown'd puppies, stinking sprats, all drenched in mud,
Dead cats, and turnip tops, come tumbling down the flood.

Ironically it was actually the cleaning up of the city which caused the major problem for the river! The city originally survived on cesspits. Below a certain density of population this was a feasible, biological method of sewage disposal - always assuming that the water supplies could be kept uncontaminated. But the invention of the water closet and the increasing population brought this to an end. Vast areas of London exceeded this critical density - so sewers were constructed to take sewage into the river. This began to solve one problem and rapidly created another -

1855: Letter to The Times from Professor Faraday -

SIR,
I traversed this day by steam-boat the space between London and Hangerford Bridges between half-past one and two o'clock; it was low water, and I think the tide must have been near the turn. The appearance and the smell of the water forced themselves at once on my attention. The whole of the river was an opaque pale brown fluid.
In order to test the degree of opacity, I tore up some white cards into pieces, moistened them so as to make them sink easily below the surface, and then dropped some of these pieces into the water at every pier the boat came to; before they had sunk an inch below the surface they were indistinguishable, though the sun shone brightly at the time; and when the pieces fell edgeways the lower part was hidden from sight before the upper part was under water. This happened at St. Paul's Wharf, Blackfriars Bridge, Temple Wharf, Southwark Bridge, and Hungerford; and I have no doubt would have occurred further up and down the river.
Near the bridges the feculence rolled up in clouds so dense that they were visible at the surface, even in water of this kind.
The smell was very bad, and common to the whole of the water; it was the same as that which now comes up from the gully-holes in the streets; the whole river was for the time a real sewer.
Having just returned from out of the country air, I was, perhaps, more affected by it than others; but I do not think I could have gone on to Lambeth or Chelsea, and I was glad to enter the streets for an atmosphere which, except near the sink-holes, I found much sweeter than that on the river.
I have thought it a duty to record these facts, that they may be brought to the attention of those who exercise power or have responsibility in relation to the condition of our river; there is nothing figurative in the words I have employed, or any approach to exaggeration; they are the simple truth. If there be sufficient authority to remove a putrescent pond from the neighbourhood of a few simple dwellings, surely the river which flows for so many miles through London ought not to be allowed to become a fermenting sewer.
The condition in which I saw the Thames may perhaps be considered as exceptional, but it ought to be an impossible state, instead of which I fear it is rapidly becoming the general condition. If we neglect this subject, we cannot expect to do so with impunity; nor ought we to be surprised if, ere many years are over, a hot season give us sad proof of the folly of our carelessness.
I am, Sir,
Your obedient servant,
M. FARADAY.
Royal Institution, July 7, 1855

Punch Cartoon on Professor Faraday's observations -

Father Thames & Prof Faraday
FARADAY GIVING HIS CARD TO FATHER THAMES
And we hope the Dirty Fellow will consult the learned Professor.

DIRTY FATHER THAMES:

Filthy river, filthy river,
Foul from London to the Nore,
What art thou but one vast gutter,
One tremendous common shore?
 
All beside thy sludgy waters,
All beside thy reeking ooze,
Christian folks inhale mephitis,
Which thy bubbly bosom brews.
 
All her foul abominations
Into thee the City throws;
These pollutions, ever churning,
To and fro thy current flows.
 
And from thee is brew'd our porter -
Thee, thou guilty, puddle, sink!
Thou, vile cesspool, art the liquour
Whence is made the beer we drink!
 
Thou, too, hast a Conservator,
He who fills the civic chair;
Well does he conserve thee, truly,
Does not, my good LORD MAYOR?

1855: Sir B Hall promised -

After five years the Thames is to receive no sewage.

Shirley Brooks (1816-1874) wrote a punning rhyme for Punch entitled 'Sink-we Scento' -

In shorter time, kind Sir, contrive
To purify our drink
For while your figure is a five,
Our river is a cinq.

French 'Cinq' = "five", punning on "sink" (sewer).

The question was raised as to where the new sewer outfalls should be. A significant fact was soon discovered by experiment -

[There was] a tidal oscillation of floats placed in the stream at Barking Creek, of about fourteen miles, increasing with the springs, decreasing with the neaps.
On an average during the passage from neap to spring tides, suspended matter would be carried UPSTREAM at the rate of about one mile per day, and during the passage from springs to neaps, it would be carried DOWNSTREAM at the rate of about two miles per day.
In a complete lunation of fourteen days, suspended matter would pass about five miles downstream.

The above quotation must still be more or less valid - and describes what happens today when overloaded sewers discharge into the river!
It goes down stream at about TEN MILES A MONTH!

In June 1858 the smell from the River Thames was so bad journalists described it as "the Great Stink". Sheets soaked with chloride of lime were hung at the windows of the House of Commons to prevent MPs getting cholera.
Benjamin Disraeli described the river as "a Stygian pool reeking with ineffable and unbearable horror".
Sittings were suspended and there was talk of moving the law courts to Oxford.
The Great Stink was preceded by serious cholera epidemics. London saw 18,000 deaths in 1849 and a further 20,000 in 1854. Water was drawn direct from the river for drinking - even though all fish had long since died.

Jerome K Jerome wrote about Reading -

In later years, Reading seems to have been regarded as a handy place to run down to, when matters were becoming unpleasant in London. Parliament generally rushed off to Reading whenever there was a plague on at Westminster; and, in 1625, the Law followed suit, and all the courts were held at Reading.
It must have been worth while having a mere ordinary plague now and then in London to get rid of both the lawyers and the Parliament.

1858: July 17th, Article in The Athenaeum, Edwin Lankester -

THE SILVER THAMES
London suffers the worst evils of a double government. With a municipality on the one hand, having no power or influence over nine-tenths of the inhabitants, and an imperial legislature on the other hand, composed, for the most part, of persons who know little, and care less, about London, it is no wonder that this great city lacks that supervision which its health demands.
But the time has come when the state of the Thames threatens even the existence of the legislature on its banks; and we may have to thank the accident of the locality of the Houses of Parliament for the suppression of the foulest nuisance that ever disgraced the annals of a nation.
Whilst action is lingering, it may be worth while to examine a little into the nature and causes of the evil, of which all have so much reason to complain. When these are known, a much better opinion may be formed of the feasibility or desirableness of any of the numerous plans which have been proposed for abolishing the great Thames nuisance.
In order to do this, there are four points which demand attention, and which have been more or less regarded by those who have written on the subject. These are —
F irst, the water itself;
Secondly, the gases it emits;
thirdly, the mud it deposits;
and, fourthly, the behaviour of these in relation to heat.
First, with regard to the water. As everybody knows, it is a compound of oxygen and hydrogen gases. This knowledge is not an indifferent matter. The water is sometimes decomposed; its oxygen is imparted to its contents, and the hydrogen, combining with some other element, rises into the air in the form of a stench. One important point may be observed here; and that is, that the water by itself never decomposes. Oxygen and hydrogen have too strong an affinity to separate spontaneously; but oxygen may be enticed from its allegiance, and hydrogen left to form those corrupt alliances, of which sulphuretted hydrogen is an example. Water, in fact, by itself is never corrupt, — it may be distilled pure from the vilest compounds, — and thus it is evident that all the noxious influence of the Thames arises from something besides the water.
Water is seldom pure in nature: it has a vast dissolving and suspending power. Hence we find in it salts, gases, and organic matters. These are all found in the Thames. The quantity of salts found in the Thames varies from 18 or 20 grains to 100, or even more. As it is supplied to us from above Teddington Lock, it contains about 22 grains. But where it flows through London, this quantity, at certain points, is very much increased. The nature of the saline matters in the river is much the same, except in one important ingredient, and that is chloride of sodium (common salt). The quantity of this ingredient above Teddington Lock is scarcely perceptible; but as we pass down the river it becomes more and more evident, till at last it exists in quantities of from 10 to 50 grains in the gallon. Now, it might be supposed that this ingredient was brought up the river from the sea, were it not for the fact that its origin is sufficiently accounted for by its presence in the sewer-water that is constantly emptying itself into the Thames. The water which comes from the Thames above Teddington Lock, supplies London before it again returns to its native stream, and in its cleansing and purifying course it dissolves this necessary substance of human civilization. Its presence in the Thames is indicative of the proportion of sewage-water that is present in the river. The chloride of sodium, however, is not in itself an injurious compound, nor do its elements become so by decomposition.
It is different with another salt found in Thames water, and to which little attention is paid. This is sulphate of lime. It is contained in Thames water in the proportion of from 3 to 5 grains in the gallon. The sulphates have the curious property of being decomposed in contact with organic matter. The sulphur of the sulphate is liberated in company with hydrogen, and the well-known smell of sulphuretted hydrogen is obtained. That this is a source of a certain amount of the stench emitted by the Thames is rendered exceedingly probable by the fact that if Thames water be kept for a few days in the same bottle, in hot weather, it gives off sulphuretted hydrogen. Those who neglect to empty the waterbottle on their washing-stands from day to day will have experienced this. It frequently occurs in neglected cisterns, and is probably the great source of the offensive smell of the Thames.
The other salts in the Thames water may be passed over as having no connexion with its present condition. Several of them, however, as the nitrates and phosphates, are not the natural products of the river water, but, like the chloride of sodium, point to their origin among the human habitations on the banks of the river.
The next group of substances which demand attention in the water are the organic matters. They originate in plants and animals, and are either living or dead. The latter are dissolved or suspended. Wherever water is exposed to the light and heat of the sun, there the germs of plants and animals penetrate and are brought into life. These dying, give up their soluble constituents to the water, and form the dissolved organic matter which is constantly present in river waters. Even in the filtrated Thames water supplied by the London companies, this soluble organic matter is found in the quantity of from one grain and a half to two grains in the gallon. Under ordinary circumstances, this matter is very constant, but when in large quantities, it decomposes and affords fresh carbonic acid for plants, and those again are followed by animals, which dying, augment the original mass by withdrawing new elements from the air.

As long, however, as plants can appropriate the elements of the decomposed organic matter, no putrescence occurs, and it is not till the dead organic matters are so copious as to act upon the life of the plants that offensive gases are discharged from the organic substances. This will have been witnessed by every one who has attempted the culture of plants and animals in a fresh-water aquarium. It will also account for the fact, that however large may be the quantity of living organic matter that may exist in water, the water remains pure and free from smell as long as the plants live. If a forest of living plants could be introduced on the bed of the Thames, they would, even in its present filthy state, clear it in a few days. Such is the influence of living vegetation on the atmosphere of the earth. Every one knows, if we could take the sewage of London and pour it over the vegetation in its neighbourhood, that it would result in crops of unbounded fertility.
But the organic matter we have in the Thames is not a natural product, and it cannot be conveyed away by natural means. Man pours into the Thames the refuse of a hundred towns and villages, besides the washings of manured lands before it gets to Teddington Lock. The water already impure is taken at the rate of 100,000,000 of gallons a day, and after washing London and its inhabitants, inside and out, is again returned to the Thames, bearing with it the vegetable and animal refuse of dwelling-houses, mews, cow and slaughter houses, and all sorts of manufactories in which organic matters are used.
Each gallon of this water carries from fifty to two hundred grains of organic matter to the Thames. This is the matter which, acting upon the sulphates of the water, decomposes them, and sends out sulphuretted hydrogen into the air. This matter is also itself decomposed. From the time it comes in contact with the water, the force which held it together as organized matter becomes more feeble. Gradually the inorganic law asserts its supremacy, and that which waft albumen, gelatine, cellulose, sugar or starch, becomes converted into carbonic acid, ammonia, sulphuretted, phosphuretted and oarburetted hydrogen, and numerous other smelling and non-smelling compounds. These are the compounds which greet the nose, and render stronger and sweeter smelling substances more pleasant. These are the gases which, being easily decomposed by chlorine or chlorides, by oxygen, or some of its compounds, have called into existence the various deodorizing or, as they have been too hastily called, "disinfectant"' compounds.
That when inhaled these gases are depressing and nauseating, there is abundance of evidence to prove. That they predispose the system to disease and cause it readily to succumb to fevers and inflammations is exceedingly probable. That they give fevers or cholera is more than doubtful. It is, however, impossible to deny that there is a host of evidence in favour of decomposing vegetable matter exciting, without scent or smell, an influence upon the human system of the most deadly and injurious kind. This influence is supposed to be material, and has been called malaria. It cannot be denied that this influence may be exerted by the Thames at the present moment.
Water collected from the Thames itself within the last fortnight contains as much as from ten to forty grains of this organic matter. No one would think of drinking such water; but even when the organic matter is in small quantities the greatest danger arises from drinking it whilst this matter is decomposing. It is in this state that it engenders diarrhoea and becomes the great provider of victims for cholera. This has been so fully demonstrated that it need not now be dwelt on here.
In what has been stated above the sources of gases in the water have been partly indicated. All waters naturally contain carbonic acid and oxygen gases. Water readily absorbs carbonic acid gas and obtains it from the respiration of water animals and from the atmosphere. It is the source of food to plants, and all vegetation in water ceases where it does not exist. It is the great bridge of death between the life of the plant and the animal. It is abundantly thrown off from organic matter in a state of decay.
Water also dissolves oxygen. It obtains it from the plants which grow in it. The more living plants in water the more oxygen it contains. Oxygen is not less powerful when free in the water than in the air. Ever hungry for union with other elements, it lays hold of hydrogen, nitrogen, sulphur, phosphorus, and carbon, converting them into water, nitric and sulphuric and phosphoric and carbonic acids. Hence ite purifying influence. Where oxygen is abundant the noxious gases of the organic matters cannot make their appearance. The way plants purify water is by the oxygen they give off. If we introduce oxygen by any other way into impure water the effect is the same. It is in this way that the permanganates of soda and potash act as deodorizers. At this moment the question of taking all smell from the Thames is simply the expense of the necessary quantity of the permanganates.
Another gas demands attention, and that is ammonia. It is composed of hydrogen and nitrogen, and appears to be the great source of the supply of the latter element to plants. It exists in the atmosphere and probably in small quantities in all water. It exists largely in the Thames. Combined with sulphur it gives to it part of its unpleasant odour. It is given off from all animals, and one of the first compounds presented after the tissues of an animal have ceased to be organic is carbonate of ammonia. The source of this substance, then, in the Thames is the same as is the chloride of sodium and the organic matters. It is, however, readily oxidizable in water, and is converted into nitric acid and water. Here is the source of the nitrates of waters and the suspicion with which they ought to be regarded.

But our inquiries into the condition of the Thames would be imperfect unless the mud which is so conspicuous on its banks had our attention. The great proportion of this substance, at least from 80 to 90 parts in every 100, is composed, as is the mud of most rivers running over clay beds, of clay and sand. The rest of it, however, is composed of organic matters — that part of the organic matter which is suspended in the water is gradually deposited and mixes with the clay and the sand.
This organic mud is again of two kinds. Partly matter which has undergone a process of putrefaction, and partly that which has not. The first is principally carbon, in that form in which it is found in the humus of the chemist or the mould of the gardener. In this state it blackens the river when stirred up, but has nothing to do with the offensive gases which it gives off. It is the latter form, the putrescible or unfermented part of this mud, which on being stirred decomposes and emits the noxious gases. There can be no doubt that this last form is principally derived from the sewage. It is this matter which is deposited so largely in our imperfectly constructed sewers, and which engenders the offensive effluvia thrown out from the gullies and shafts of our street sewers. If it could remain quiet at the bottom of the river it would decompose slowly and cease to be offensive; but it is perpetually stirred by the tide and the steamers, and thus contributes to the stench.
With these facts before us we are now prepared to investigate the question as to how it is the river becomes so much more offensive in the summer. During six months in the year the temperature of the Thames seldom rises above 50° Fahr[enheit], and during this period little or nothing is heard of the offensiveness of the Thames; but in the summer it rises sometimes to 70°. It was 72° during the second week in June. What, then, is the effect of this heat?
In the first place, it facilitates chemical change. Animal and vegetable substances which would remain fresh for weeks at 40° become putrid in a few hours at 70°. But this is probably not the principal effect of heat. Water at a low temperature holds in solution much larger quantities of the gases it dissolves than at high temperatures. This is most important in relation to the great purifying element, oxygen. As the temperature of the water increases it loses more and more of its oxygen, and of its capacity to take up that which may be thrown into it by living vegetation. This may be seen on a warm day in an ordinary aquarium, when bubbles of oxygen may be observed streaming from the green leaves of the plants and escaping on the surface of the water from its inability to retain the oxygen in solution. This is the reason why fishes die in ponds and aquaria after exposure to heat, as the water no longer contains the oxygen necessary to their life. Oxygenate the water by constant agitation and the animals will live. This explains the purifying action of the falling of water over a dam or its separation by the intervention of rocks or precipices. If our steamers stir up the mud with their paddles, they at least oxygenate the water.
It is not till water has lost all its oxygen, that such offensive gases as sulphuretted and phosphuretted hydrogen can escape. This, then, is one of the great causes of the smell from the Thames: the expulsion of the oxygen by heat.
The source of the temperature of the Thames water is not, however, the direct action of the rays of the sun alone. The temperature of reservoirs of water not collected from the Thames, has not been so great as the Thames by several degrees. The reason of this is found in the action of the sun on the dark absorbent mud, so extensively exposed at low water. On some days in June last the mud of the Thames was found to exhibit a temperature of 120° Fahrenheit. Here, then, we have clearly a source of heat, which will account for the high temperature of the Thames, and explains the tendency to putrescence which all rivers with extensive mud-banks occasionally present in hot summer.
From these remarks it will be clearly seen, that the origin of the present condition of the Thames is the organic matter poured into it from the common sewers of London. The diversion of this mass of putrescible matter is, clearly, the only remedy that can restore the river to its pristine beauty and usefulness. But it has already been determined by our legislature that the water is not to be drunk, and that the Thames is to be made the great trunk sewer of London filth, and the water companies have spent millions in getting their supply of water from above Teddington Lock. If this course is to be persisted in, we must look to such remedies as deodorization, the diminution of the temperature, and the quickening of the current of the water.
At the same time, it should be recollected that these can only be regarded as temporary expedients. Every year the population of London increases, and at last the same evil will recur. It is surely the wisest plan to spend the money which a temporary expedient would cost, in helping on the great work, which must be done at last, and that is, the diversion of the sewage from every portion of the river in which it is at all likely the evils of which we now complain can again arise.
Edwin Lankester.

Charles Kingsley -

Clear and cool, clear and cool,
By laughing shallow and dreaming pool;
Cool and clear, cool and clear,
By shining shingle and foamimg weir;
Under the crag where the ouzel sings,
And the ivied wall where the church-bell rings;
Undefiled, for the undefiled;
Play by me, bathe in me, mother and child.
 
Dank and foul, dank and foul,
By the smoky town in its murky cowl;
Foul and dank, foul and dank,
By wharf and sewer and slimey bank;
Darker and darker the further I go,
Baser and baser the richer I grow,
Who dare sport with the sin-defiled?
Shrink from me, turn from me, mother and child.

Construction of London's Victorian Sewers

Until the early 19th century, London's River Thames, contained relatively clean water.
Some 200 years before this, Sir Christopher Wren (1632-1723) realised that drainage and sewage disposal would sooner or later prove a major problem in an expanding city. He designed a relevant system; however, this was not constructed ...
In the early 19th century there was little or no consistency regarding sewage disposal in different districts of the metropolis; cesspools were regarded as the proper receptacles for house drainage.
However, things were to change suddenly, and in the 1840s it became compulsory to drain houses into sewers (all of which ultimately ran into the Thames); within six years, more than 30,000 cesspits were systematically abolished, and "all house and street refuse was turned into the river".
This inevitably meant that Thames water (from which domestic water supplies were derived) was heavily contaminated by sewage; popular newspapers and journals launched a campaign for cleansing Thames water.
The Chief Municipal Engineer to the Metropolitan Board of Works was at this time Joseph William Bazalgette (1819-91)
Still in his 40s, he designed (in conjunction with Colonel William Haywood 1821-94) and supervised, the building of an elaborate system for London's sewage disposal. Three objects were kept in view:
(i) waste disposal
(ii) land drainage
(iii) introduction of a (safe) water supply system.
An important a priori consideration surrounded the fact that the Thames is tidal, that is, if a dead horse was thrown into the river at Westminster or the city of London, it would be taken a few miles down river only to return on the next (incoming) tide, that is, it would not be transported to the estuary, and hence to the (open) North Sea.
In order to circumvent this, Bazalgette designed a system of sewers from which, by means of four huge pumps, it was possible to discharge London's sewage into the Thames at Barking Creek (northern) and Crossness (southern), via outfall sewers (that is, well to the east of London, past the tidal segment of the Thames).

Recently there have been further concerns that raw sewage escapes into the river at times when the sewers are overloaded with flood water. Whilst much remains to be done to correct this it will obviously be expensive. Not least at risk from this are recreational water users.

2006: Sewage upstages river race -

More than a million tonnes of sewage flowed into the River Thames as thousands of people prepared to take to the water for last Saturday's Great River Race. On Thursday, September 14, 2006, sewage flowed into the Thames as heavy rain filled London's sewers.
The pollution, seen mainly in the Barnes area, caused a drop in the river's oxygen levels - threatening thousands of fish.
[ AND HUNDREDS OF PARTICIPANTS! ]

2006: Thames Stategy East, Consultation, -

Part 3, p.26 -
The water quality of the Thames has improved over the years, initially due to the introduction of the new combined sewerage system and more recently in the 1960s due to more advanced sewage and industrial effluent treatment. This has resulted in an improvement in water quality and consequent recovery of the ecosystem, including fish species. The Thames now supports 121 species of fish [ and this presumably refers to below Teddington]
Because of the legacy of the Victorian combined sewerage system, pollution still enters the Thames during periods of high water flows, and is ameliorated by the Thames Bubbler which oxygenates the water at specific inflow points. Consequently ... much remains to be done to continue cleaning up the river and its tributaries.
Part 3, 3.2, p.28 -
The Thames is a tidal river and the character of the river changes throughout the tidal cycle, contrasting mostly at low tide when extensive mud flats are visible in some sections of the river and its tributaries. The high sediment loading is maintained in suspension by the tidal action and colours the water of the Thames giving rise to the belief that the Thames is not clean.
The Thames is in fact recognised as one of the cleanest metropolitan estuaries in the world.

2010:

Black & Veatch has been selected by Thames Water as principal contractor to upgrade and extend Mogden Sewage Treatment Works in West London. Construction will start in spring 2010 to significantly reduce the amount of storm sewage that overflows into the River Thames during heavy rainfall when the site becomes overloaded.

[ It is totally unacceptable that any untreated sewage should reach the river at any time. "to significantly reduce the amount of storm sewage" is mealy mouthed - either do it completely or find a better way! The complete separation of rainwater and sewerage systems is essential. It may be expensive - but there is ultimately no choice.
NB: the unexpressed argument which may be implied is that at times of high rainfall the Thames flow would rapidly deal with the problem. THIS IS NOT THE CASE! (it may sometimes be true - but high London rainfall may occur when the river flow coming downstream is low) - and then the Victorian research quoted above would apply - pollution moves downstream at about TEN MILES A MONTH!

However I think it should also be pointed out that a great deal has already been achieved (and so we are grateful to various people past and present for that) and that
ALL RIVER USERS ARE AMBASSADORS FOR THE RIVER
We do ourselves no favour by presenting the river as if it is still as it was in the bad old days - it isn't - though until there is a total absence of sewage - it is still unacceptable ]