RIVER THAMES, the chief river of England, rising in several small streams among the Cotteswold Hills in Gloucestershire. Its source is generally held to be at a place known as Thames Head, in the parish of Coates, 3 m. W. by S. of Cirencester; but claims have also been advanced on behalf of the Seven Springs, the head waters of the river Churn, 5 m. S. of Cheltenham. The length of the river from Thames Head Bridge to London Bridge is i6ij m. and from London Bridge to the Nore, 47! m., a total of 209 m. The width at Oxford is about 150 ft., at Teddington 250 ft., at London Bridge 750 ft., at Gravesend 2100 ft., and between Sheerness and Shoeburyness, immediately above the Nore, 5^ m. The height of Thames Head above sea-level is 356 ft., but that of Seven Springs, the adoption of which as the source would extend the length of the river by several miles, is 700 ft. The height of the river at Lechlade is 237 ft., the average fall between Lechlade and London, 143! m., being rather less than 20 in. per mile. The drainage area of the Thames is 5924 sq. m., including that of the Medway, which, as it joins the estuary immediately above Sheerness, may be considered a tributary of the Thames. The Thames forms part of the Gloucestershire-Wiltshire boundary to a point below Lechlade; thence for a short distance it separates Gloucestershire from Berkshire; after which it separates successively Oxfordshire and Berkshire, Buckinghamshire and Berkshire, Middlesex and Surrey, and finally, at its estuary, Essex and Kent. In the succeeding paragraph the bracketed figures indicate the distance in miles above London Bridge.
The upper course lies through a broad valley, between the foot-hills of the Cotteswolds on the north, and the slight elevations dividing it from the Vale of White Horse on the south. The scenery is rural and pleasant; the course of the river winding. Before reaching Oxford the stream swings north, east and south to encircle the wooded hills of Wytham and Cumnor, which overlook the city from the west. The Windrush joins from the north (left) at New Bridge (126}), the Evenlode near Eynsham (119), and the Cherwell at Oxford (112). Between Lechlade and Oxford the main channel sends off many narrow branches; the waters of the Windrush are similarly distributed, and the branches in the neighbourhood of Oxford form the picturesque " backwaters " which only light pleasure boats can penetrate. The river then follows a valley confined between the hills on either side of Oxford, passes the pleasant woods of Nuneham, and at Abingdon (103!) receives the Ock from the Vale of White Horse. At Dorchester (95$) the Thame enters on the left, and the river then passes Wallingford (90!) and Goring (85). Hitherto from Oxford its course, though greatly winding, has. lain generally in a southerly direction, but it now bends eastward, and breaches the chalk hills in a narrow gap, dividing the Chilterns from the downs of Berkshire or White Horse Hills. From this point as far as Taplow the southern slopes of the Chilterns descend more or less closely upon the river; they are finely wooded, and the scenery is peculiarly beautiful, especially in early summer. The charm of the Thames is indeed maintained throughout its course; the view of the rich valley from Richmond Hill, of the outskirts of London, is celebrated; the river is practically the only physical attribute to the beauty of the metropolis itself, and the estuary, with its burden of snipping and its industrial activity, is no less admirable. At Pangbourne (8o|) the Thames receives the Pang on the right, and at Reading (74$) the Kennet on the same side. After passing Reading it bends northward to Henley (65), eastward past Great Marlow (57) to Bourne End (54), and southward to Taplow and Maidenhead (49 J), receiving the Loddon on the right near Shiplake above Henley. Winding in a south-easterly direction, it passes Eton and Windsor (43!), Datchet (41$), Staines (36), Chertsey (32), Shepperton (30) and Sunbury (26^), receiving the Coin from the left at Staines, and the Wey from the right near Shepperton. Flowing past Hampton Court, opposite to which it receives the Mole on the right, and past Kingston (20$), it reaches Teddington (i8j). Passing Richmond (16) and Kew the river flows through London and its suburbs for a distance of about 25 m., till it has passed Woolwich. Gravesend, the principal town below Woolwich, is 26^ m. from London Bridge. The estuary may be taken to extend to the North Foreland of Kent. In the tideway the principal affluents of the Thames are the Brent at Brentford, the Wandle at Wandsworth, the Ravensbourne at Deptford, the Lea at Blackwall, the Darent just below Erith, and the Ingrebourne at Rainham, besides the Medway.
The basin of the Thames is of curiously composite character. Thus, the upper portion of the system, above the gap at Goring, is a basin in itself, defined on the west and south by the Cotteswold and White Horse Hills and on the east and north by the Chilterns and the uplands of Northamptonshire. But there are several points at which its division from other river basins is only marked by a very low parting. Thus a well-marked depression in the Cotteswolds brings the head of the (Gloucestershire) Coin, one of the head-streams of the Thames, very close to that of the Isborne, a tributary of the upper Avon; the parting between the headstreams of the Thames and the Bristol Avon sinks at one point, near Malmesbury, below 300 ft. ; and head-streams of the Great Ouse rise little more than two miles from, and only some 300 ft. above, the middle valley of the Cherwell. The White Horse Hills and the Chilterns strike right across the Thames basin, but almost their entire drainage from either flank lies within it, and similarly a great part of the low-lying Weald, though marked off from the rest of the basin by the North Downs, drains into it through these hills. It may be noted further that the Kennet continues upward the line of the main valley below the Goring gap, and the Cherwell ' that of the main valley above it. The basin thus presents interesting problems. The existence of wide valleys where the small upper waters of the Cherwell, Evenlode and Coin now flow, the occurrence of waterborne deposits in their beds from the northwest of England and from Wales, and the fact that the Thames, ike its lower southern tributaries which pierce the North Downs, las been able to maintain a deep valley through the chalk eleva:ion at Goring, a_re considered to point to the former existence of a much larger river, in the system of which were included the upper waters of the present Severn, Dee and other rivers of the west. The question, in fact, involves that of the development of a large part of the hydrography of England.
. The Thames about Oxford is often called the Isis. Camden gave currency to the derivation of the word from the combination of the names Thame and Isis. But it can be shown conclusively that the river has borne its present designation from the earliest times. Caesar (De Bell. Gall. v. n) says that at the time of his invasion of Britain it was called Tamesis. Dion Cassius (xl. 3) and Tacitus (Ann. xiv. 32) both call it Tamesa, and in no early authority is the name Isis used. In early Saxon times the river was called Thamis, as may be seen in a grant before A.D. 675 to Chertsey Abbey by the sub-king Frithwald. In the first statute passed for improving the navigation of the river near Oxford (21 Jac. I.) it is called the river of Thames, and it was only in a statute of George II. (1751) that the word Isis appears. The name Isis has indeed the authority of Spenser as applied to the Thames in its course above Dorchester (Faerie Queen, Bk. iv. canto xi. stanza 24), but there is ample evidence to show that long before his time the name of the river throughout its course was not Isis but Thames. The word Isis is probably an academic rendering of Ouse or Isca, a common British river name, but there is no reason to suppose that it ever had much vogue except in poetry or in the immediate neighbourhood of Oxford.
The flow of the Thames varies greatly, according to the season of the year. The average gaugings at Teddington for the summer months of the years 1883 to 1900 were in July 413,000,000 gallons a day, in August 395,000,000 gallons, and in September 375,000,000 gallons. The normal natural flow in ordinary summer weather is about 350,000,000 gallons a day, and of this, after the companies have taken 130,000,000, only 220,000,000 gallons are left to pass over Teddington Weir. After a long period of dry weather the natural flow has been known to fall considerably below 200,000,000 gallons, whilst, on the other hand, in the rainy winter season, the flow in 1894 rose for a short time to as high a figure as 20,000,000,000 gallons, and the ordinary flow in winter months may be put down as 3,000,000,000 gallons. The importance of storage reservoirs is manifest under such conditions of flow, especially bearing in mind the growth of population in the London district and of its increasing needs. The water-supply of London is considered under that heading; it may be noted here that the Thames forms the chief source of supply for the metropolis, but apart from this the corporation of Oxford and two companies in the Staines district have powers to draw water from the river, though not in any large quantities.
Throughout the whole of the Thames watershed, and especially in the 3800 sq. m. above the intakes of the water companies (at Hampton or in the vicinity), the Thames Conservancy has enforced the requirements of parliament that no sewage or other pollution shall be allowed to pass into the Thames, into its tributary streams, or even into any water communicating with them. There is a large staff of inspectors constantly visiting the various parts of the watershed, and in spite of many difficulties arising from vested interests, the work of purification is attaining completion, with a correspondingly great improvement in the quality of the river water. So recently as 1890 the state of the river below London was such as to be dangerous to the public health. The metropolitan sewage was discharged untreated into the river, and the heavier solids deposited over the river-bed, while the lighter parts flowed backwards and forwards on the tide. The London County Council, directly after its establishment, took means to remedy this evil (see LONDON).
The Thames is navigable for rowing-boats as far upwards as Cricklade, except in dry seasons, and for barges at all times as far as Lechlade, 18 m. below Thames Head. At Inglesham, threequarters of a mile above Lechlade, the Thames and Severn canal has its junction with the Thames. This canal is the link between the two great rivers from which it takes its name, or, in other words, between the east and west of England. It surmounts the watershed by means of Sapperton tunnel, 2 m. long, opened in 1789, and joins the Stroudwater canal, which completes the connexion, at Wallbridge near Stroud. It was long abandoned, but owing to the exertions of a joint committee of the counties and other interests concerned in 1895, powers were obtained from parliament for its restoration, and the works needful for its reopening were carried out. Concurrently with the repair of the canal, the navigation works on the Thames were remodelled at a large cost, and barges drawing 3 ft. 6 in. can now, even in the summer season, navigate from London to Inglesham. Although the Thames, as one of the " great rivers of England," was always a_ navigable river, that is to say, one over which the public had the right of navigation, it was not until the last quarter of the 18th century that any systematic regulation of its flow in the upper reaches was attempted. Complaints of the obstructions in it are not uncommon, and John Taylor, the Water Poet (1580-1653), in a poem commemorating a voyage from Oxford to London, bewails the difficulties he found on the passage. No substantial measures to remedy this state of things were adopted till 1771, when an act of parliament was passed authorizing the construction of pound locks on the Thames above Maindenhead bridge. In pursuance of the powers thus granted, the Thames Commissioners of that day caused locks to be built at various points above Maidenhead, and between 1810 and 1815 the Corporation of London carried out river works on the same lines as far down the river as Teddington. The works as subsequently maintained by the Thames Conservancy ensure an efficient head of water during the drier seasons of the year, and facilitate the escape of winter floods. The number of locks is 47, including four navigation weirs above Oxford. The uppermost lock is St John's, below Lechlade; the lowest is Richmond, but this is a half-tide lock, keeping the water above at a level corresponding to half that of flood tide. Under ordinary conditions the sluices are raised to admit boats to pass from the half flood to half ebb, so that the river remains tidal up to Teddington, the next lock.
The canals in use communicating with the Thames, in addition to the Thames and Severn canal, are the Oxford canal, giving communication from that city with the north, the Kennet and Avon canal from Reading to the Bristol Avon, the Grand Junction at Brentford, the Regent's canal at Limehouse, and the Grand Surrey canal at Rotherhithe. A short canal connects Gravesend with Higham. Navigation is also carried on by the Medway to Tonbridge, on the lower parts of the Darent and Cray, from Dartford and Crayford, and on the Wey up to Guildford and Godalming. The Woking, Aldershot and Basingstoke canal joins the Wey, but is little used. The Wilts and Berks canal, joining the Thames at Abingdon, is disused. By means of the Grand Junction and Oxford canals especially, constant communication is maintained between the Thames and the great industrial centres of England. The trade on the upper Thames is steady, though not extensive. The vast trade on the estuary, which lies within the bounds of the port of London, is considered under LONDON.
The utility of the river is great in the opportunities for exercise and recreation which it affords to the public, especially to Londoners. The scene on any part of the river from Oxford down on public holidays, and on Saturdays and Sundays during the summer, would be sufficient to show how it contributes to the public enjoyment. It is only since about 1870 that this popularity has grown up. Ten years earlier even rowing-boats were few excepting at Oxford, at Henley in regatta time, and at Putney on the tideway. Steam launches did not exist on the river before 1866 or 1867, and houseboats only in the form of college barges at Oxford. But by 1900 there were 541 launches, 162 house-boats, and 11,284 rowing-boats. Each boat is registered, a small tax being charged; while there are fixed prices for the passage of locks. During the season regattas take place at many of the towns and larger villages. Of these Henley Royal Regatta is pre-eminent by the number and importance of the entries, and by its comparative antiquity. The regattas at Molesey, Kingston, Reading, Marlow and Oxford, as well as many others, attract numerous competitors and spectators. The Oxford and Cambridge boat-race from Putney to Mortlake on the tideway, the summer eights and the " torpids " at Oxford University, and the school races at Eton and Radley should also be mentioned.
A statute of 1393 was granted to the citizens of London to remove weirs on the Thames, and empowered the Lord Mayor to enforce its provisions. For the next four centuries he acted through water-bailiffs, till in 1771 a committee of the Corporation of London took over the work. In 1857 the Thames Conservancy Board was established. Its powers were increased and its constitution varied in 1864, 1866 (till which year the jurisdiction of the river above Staines was under a large body of commissioners), and 1894, but the creation of the Port of London Authority (see LONDON) limited its jurisdiction.
Fish are abundant, especially coarse fish such as pike, perch, roach, dace and barbel. Of trout there are many fine specimens, especially at the weirs. Salmon are known to have existed at Maidenhead so recently as 1812, but they disappeared soon after that date. An association was formed under the presidency of Mr W. H. Grenfell, M.P., with the object of reintroducing this fish into the river, and in April 1901 and on subsequent occasions a number of young salmon were placed at Teddington by way of experiment. The right of the public to take fish has been frequently in dispute, but a committee of the House of Commons, which took much evidence on the question in the year 1884, came to the conclusion that " it is impossible to recognize anything like a general public right to take fish as now existing. " They added " that the public at large have only to know that their rights are imaginary to induce them also to be content with the extant system under which permission is very freely granted by owners of fisheries to the public for angling on the more frequented parts of the Thames. These conclusions are interesting in face of the fact that the question has arisen from time to time since 1884.
The fisheries are under the regulation of by-laws made by the Thames Conservancy, which apply to the riparian owners as well as to the public generally. These by-laws are carried into effect by officers of the conservators, assisted by the river-keepers of the various fishing associations. The principal associations are those at Oxford, Reading, Henley, Maidenhead and Windsor, and the Thames Angling Preservation Society, whose district is from Staines to Brentford.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)