# Meanders

Right bank. A series of increasingly sharp meanders. Keep an eye on the spire of St John's Church, Lechlade, which is almost where you are eventually going.  Sometimes you will have to look behind you!  Can it be that Old father Thames was in two minds about going to London or joining with sister Severn?

Meanders are so called after the river in Asia Minor which carried a large amount of silt.  Its bends and loops were so pronounced that the river gave its name to that sort of river feature.
It is said that it will be found that if the straight line distance between the source of a river and its mouth, is multiplied by PI (3.14), it will be found to be the distance the stream flows down the river.  I find it hard to believe most of the time, (and it may only be true of a natural uncontrolled river) - but between Buscot and St John's it is quite believable.

Click for an argument that the true figure is 1.94 - but that is quite amazing enough in its own right!
Mathematicians might like to look at an assessment of Langbein and Leopold's suggestion of the formula by which the size of meander curves is related to depth

If I understood it I would explain it here ...

Some of the meanders are so sharp that below the point on the inside, a bank of silt develops in which you can clearly see the great gouges made by boats trying to take the shortest route.  I even grounded my punt like that much to my surprise, considering that these meanders are also noted for the depth of water, in places exceeding twenty feet.

Meanders below Lechlade

I do not know a great deal about river flow, but it seems to me that the speed of a current must be inversely proportional to the depth.  In shallow places for the same amount of water to pass it must go faster.  Therefore by putting in a weir and raising the level, the current must be very much reduced.  Presumably silting occurs where the current is least - so nature is "trying" to restore the situation prior to the building of the weir.  The other factor at work of course is erosion.  The meanders occur through erosion.  But though raising the level puts the water in contact with far more soil, that contact is much gentler because the current is slower.  My observation of these meanders is that they are almost unchanged over twenty years.  The positions of the pill boxes, concrete fortifications, show that the river has changed little since they were built.  Maybe the erosion has been so reduced that the meanders have been "frozen" at the moment that the weirs were built.

1802: Fred Thacker (in 1921) -

In June of [1802] a cut was proposed across Bloomer Meadow near Buscot Cheese Wharf: a step often suggested to avoid some of the worst bends hereabouts, but not even now realised.

1896: 'A Tale of the Thames' by Joseph Ashby-Sterry [going downstream in a skiff]

It did not take them long to reach Saint John's, which is the first lock on the Thames, and pass through it into the singularly curly stream beyond. In places it here curves so much that you appear to be constantly returning to the point whence you started. It requires no little skill in steering in these waters, for in places the stream is very swift, and you have to anticipate the sudden turnings before you reach them. ...
A little way after passing Saint John's Lock, the stream altogether quits the county of its birth, Gloucestershire, and henceforth [going downstream] becomes the boundary between Oxfordshire and Berkshire.

1937: "The Thames and its Story" -

There are a quietude and utter rurality about the river from Lechlade till within the precincts of Oxford that will be looked for in vain upon the busier haunts. Progressing from Lechlade downwards one feels altogether removed from the haunts of men. A patient angler sitting in his boat under the overhanging boughs of a tree will be occasionally passed, and the presence of labourers toiling in the meadows is evidence that this is not wholly a "Sleepy Hollow". The solitude is, in truth, delightful.
As one drops down between the banks one sees drawn up in review order regiments of familiar friends - the dark, glossy leaves of the water dock, bursting into seed in July; huge clumps of blue forget-me-nots that can only be plucked from a boat; ox-eyed daisies, well above high-water mark, gleaming as fixed stars in the floral firmament; the yellow-flowering great watercress, the purple loosestrife beginning to blossom, yellow iris, the white flowers of the common watercress, the pin persicaria, meadowsweet, the comfreys, and sometimes a clump of arrowheads.

New Footbridge at Bloomers Hole, 2000

The new footbridge at Bloomers Hole.  I saw this put in place by helicopter in 2000.  It is made of steel clad in wood.