River Thames

I am not totally clear what you mean in your question wording by "middle source" but as I live on the River Thames and have often navigated up and down the River Thames on merchant ships and further westwards on smaller boats, I will try to explain main features as I know them from my own experiences, which I hope will give you the information you are seeking?

Firstly the River Thames with its various source tributaries is the longest river in the UK and flows through the middle of London, England's capital system. The Thames effectively first starts or "rises" near Cirencester in the Cotswold Hills and follows a course of 330 kilometers to the Nore. At Gravesend the head of its estuary where the River pilots hand over ship navigation to the deep-sea pilots, the Thames has a width of a kilometre increasing thereafter to 16 kilometers at the Nore between Essex and Kent where the Thames finally debouches into the North Sea at its mouth.

Going up river through London, the River's tidal waters reach Teddington which is 100 kilometers from the River's mouth.where the first lock from the sea, apart from the tidal lock at Richmond, is located. Then as you go up River further west there are 46 more locks, St Johns Lock near Lechlade being nearest to the source of the Thames in the Coltswolds.

An important feature is The Thames Barrier which spans 520 metres across the River Thames near Woolwich, and it is designed to protect 125 square kilometres of central London from flooding caused by tidal surges. It became operational in 1982 and has 10 steel gates that can be raised into position across the River. When raised, the main gates stand as high as a five-storey building and as wide as the opening of Tower Bridge each main gate weighing 3,300 tonnes.There is no dount it sabed many parts of London from flood damage in the recent weather.

But I think drom your question's wording, you may be seeking information about the middle part of the Thames which is often termed the "Thames Valley" rather than its part around London? The Thames Valley has featured in the news a lot in recent months due the terrible flooding in places like Oxford and Wraysbury. A reason for this is there are several tributaries that enter the Thames in the Thames Valley where people enjoy boating. There is the River LODDON which starts within the urban area of Basingstoke in Hampshire, and in its first mile flows under the Festival Place shopping centre that forms the main part of the central area of Basingstoke flowing to meet the Thames near the village of Wargrave in Berkshire. The Loddon has a total length of 45 km and, together with its tributaries, drains an area of 400 square miles.

Then there is the River KENNET which has sources at Swallowfield Spring in Wiltshire and a collection of tributaries to the North of Avebury and it joins up with the waters from Swallowhead Springs. The upper reaches of the River Kennet are served by two tributaries. The River OG which flows into the Kennet at Marlborough in Wiltshire and the River DUN which enters at Hungerford in West Berkshire. The Kennet's principal tributaries below Marlborough are the Rivers LAMBOURNE, ENBORNE and the FOUNDRY BROOK.For several kilometres to the west of and through Reading, Berkshire, the Kennet supports a secondary channel, known as the HOLY BROOK which formerly powered the water mills of Reading Abbey.

Another well known tributary is called the River THAME (note to confuse us all it is spelled same as 'thames' except it has no S on the end)! Its source is several small streams which rise in the vale of Aylesburyon, Buckinghamshire on the north side of the Chiltern Hills. These streams converge north-east of Aylesbury.

Then there is the River PANG which a small chalk stream river in West Berkshire which runs for approximately 23 kms from its source normally near the village of Compton although the exact location of the river Pang's source varies depending on rainfall levels. In times of high rainfall it can be as far back as Farnborough some six kms to the north-west, whilst at other times it may be as far downstream as Hampstead Norreys. The Pang flows down to its confluence with the Thames right through the village of Pangbourne which is well known as being the location of the Royal Naval College.

Then another important source tributary further up the Thames is the River CHERWELL which rises near Hellidon in Northants and flows south through Oxfordshire for 64 kilometres to meet the Thames at Oxford where it adds a significant discharge to the Thames and has caused a lot of flooding in that city when there has been heavy rain.

Other key points about the middle of the Thames you may be inquiring about; historically until the 19th century , the London Thames was an important means of transport for passengers; the names of stairs are traces of the great passenger barge traffic. Since World War II, passenger traffic has been revived by water buses and hydrofoils. Henley on Thames in south Oxfordshire is also famous all over the world for the annual Regatta highlighting rowing.