Christchurch Meadow, RIGHT bank in Oxford

Christchurch Meadow in 'Oxford' by Frederick Douglas How -

Far smaller in extent [than Port Meadow], but even more famous, is the tree-girt space called Christ Church Meadow, lying between that college and the river.
Port Meadow may be said to be a wide bright outskirt of the natural robe of Oxford: Christ Church Meadow, with its Broad Walk and its mighty trees, is like a fold about her feet deep-trimmed and bordered with a silver braid.
It is here that on Show Sunday, in Commemoration Week, in June, those who hold high places in the University, with favoured guests, and some few undergraduates, pace up and down, or used to pace in days gone by; for it belongs to a more modern pen to say whether the old custom still obtains, or whether it has passed away with other things of ceremony ...

Lantern Slide (1883-1908) - Oxford University Barges
Pictures by W.C.Hughes. Thanks to Pat Furley, research by Dr Wilson.

1906: Christchurch Meadows from the River, Oxford by Andrew Lang -

1906, Christchurch Meadows, Andrew Lang
1906, Christchurch Meadows, Andrew Lang

1908: Isis Boatclub Oilette -

1908, Isis Boatclub Oilette
1908, Isis Boatclub Oilette

1922: Punts below Folly Bridge, Francis Frith -

1922:  Punts below Folly Bridge, Francis Frith
1922: Punts below Folly Bridge, Francis Frith

1934: College Barges -

College Barges, 1934
College Barges, 1934

1822: 'Christchurch Walk' in 'The University and City of Oxford'
View from Christchurch Walk -

By Christchurch Walk, 1822
By Christchurch Walk, 1822

On the right hand end of the bridge I think you can see that it was lockable -
1880: Church, Summer Days-

the towpath was blocked by a lofty door, defended with formidable rails ... in the interests of the watermen, who made a rich harvest by ferrying passengers across from Christ Church Meadows.

1937: "The Thames and its Story" -

... the college barges ... are an interesting study in development. The first of them were old procession barges of the London City Companies. One of them, the Oriel barge, still remains, with its delicate form, and long sharp prow, in which the rowers sat. The bronze figures by the door of the saloon are untouched, the oval windows, the tarnished gilding within.
But the spirit of utility rebelled and the model changed. The long prow was chopped off close, the semblance of the high stern went, and there was left merely a square floating dressing-room with railings round its roof, and seats for the spectators of the races.
Then the sense of beauty mutinied, perhaps alleging the use of the toy for picnic excursions, and the prow and stern were restored.
The University barge is a monument of the Gothic revival. Several architects have tried their hand in designs for these craft, and new ones are from time to time constructed.
It is the oddest little street, this row of motley Noah's Arks; and when the high poles shake out their amazing flags, and the men come down in fearless college colours, and a vaste and diverse millinery decks every foot of standing the roofs can give, there would seem to be some touch of an Arabian Night about a very English day, were it not that the vigorous people wear many more colours than Arabia would allow.

Lament for the University College Barge, sold in 1965 -

And so she had to go
Was sadly moved away
Instead the water flow
The gap remains today

Toll for the Barge!
Stout Bossom has now gone
His last load poled across
His ferrying done

The dripping landing stage
Where Univ boats made fast
the roof where every age
Has watched Eights racing past

The cheerful cabin's glow
The pictures on each wall
The oars of famous crews
Sweet cakes and teas for all

A floating common room
Set in a silver stream
This seat of Isis, whom
all hold in high esteem.

All this is now a dream
Our Barge's days are o'er
Proud prow and painted beam
Shall ride the Thames no more.

This whole stretch shouts to me that its level has been changed.
As D S Mackoll wrote in The Royal River in 1885:
the river has banks instead of brims

... another question, that of floods, presses as much as ever. Quite recently the engineer to the Thames Commission brought out a scheme for doing away with Iffley Lock and Weir, and dredging a deep and narrow channel between Iffley and Folly Bridge. The Vice-Chancellor and the Dean of Christchurch, both by virtue of office Commissioners, were in favour of this scheme with a view to Oxford health; but it has been proved to the satisfaction of the Thames Conservancy Board, whose officers have examined the place, that so sweeping a change is not needed.
The effect of the change would be to give the river banks instead of brims, and it has been argued that it would kill the elms of Christ Church and the fritillaries in the water meadows about Iffley. Most serious of all would be the loss of Iffley Mill. We may hope that Oxford health need not be bought so dearly.

Fred Thacker, The Thames Highway, Volume II Locks and Weirs, page 133 says -

Towards the end of this year [1885] a very determined local effort was made towards abolishing the [Iffley] lock, mills and weirs. The level of the River up to Folly Bridge was to be lowered 2ft 6in, but the bed was to be dredged so that there should be a uniform depth of about five feet. Several local petitions, however, perhaps decided the Conservators against any interference with the station.

So, as yet, I cannot pin down any reference to actually reducing the levels. But my evidence that it was done is clear to me. The height of the wharf at the Head of the River; the height of the walls by Magdalen Bridge; the banks all the way down to Iffley Lock (where the river would be expected to be close to bank level) all show it to be so.
Any evidence of the change to weir or lock would have been removed by the extensive rebuilding of the Iffley Lock area in the 1920s. And I do know that extensive dredging was done (which of course would have been a necessary move after levels were reduced) witness the following photo, they dredged the hard way in those days! If you look carefully I think you can see that the level has been recently reduced. -

Dredging at Oxford, 1885
Dredging at Oxford, 1885, Henry W Taunt
© Oxfordshire County Council Photographic Archive; HT219

 

Bottom Ice in the Freshwater Thames!

One of the great scientific facts of my childhood was the understanding that whilst most liquids become denser as they get colder this only applies to water down to a point, and that point is at about 4°c. Water is at its densest at this temperature and then as it cools further it actually gets less dense.
This strange quirk of nature is probably responsible for the survival of life on earth and certainly for life on land. Together with the fact that ice is less dense than water and therefore floats - it means that even relatively small bodies of water never freeze through to the bottom - and therefore life could survive.
The convection currents caused by water cooling at the surface, becoming denser and falling, cease at 4°c and even reverse (colder water being forced to the surface where it freezes and insulates the rest).
I write this because I have recently discovered the following:
It is in "Oxfordshire of One Hundred Years Ago" by Eleanor Chance.
W E Sherwood writes -

There is another thing which I suspect the Conservancy, by their dredging, may have stopped, but I am not certain, as it is so long since we have had a severe winter, and that is the formation of 'ground ice', ice that is that forms on the bottom of the river.
When I spoke to my science master about it he talked about the maximum density of water, and told me that the thing was impossible, but I took him down to the river, and showed him, opposite the barges [ie the College Barges along the RIGHT bank at Christchurch Meadow], the bottom all covered in ice.
I think he was annoyed, but at the river for behaving so unaccountably - indecently even, he seemed to think - and not at me. He was so far right that in a lake or in a river of uniform depth the ice cannot so form, but in the Thames in those days there were deep reaches followed by banks of gravel over which the water was shallow.
In times of frost the heavier warmer [ie 4°c] water sank and remained in the deep parts, and what flowed on was the lighter water at or close to freezing point, and when the crystals formed in this they attached themselves, as forming crystals will, to any solid they could find; in this case to the gravel at the bottom.
This ice rose from time to time in spongy masses, bringing with it some of the gravel, and floated on until it reached the lock. Here it packed, and if the frost continued, formed a thick mass of rough ice which, as more came down extended further and further up stream; and it was on this ice, far more than surface ice, that on three occasions I remember a coach and four was driven from Folly Bridge to Iffley.

Frozen Isis 1890
A Coach and four on the Frozen Isis, 1890?

Owing to the deepening of the river I doubt that this will ever again be possible, though at Binsey, the other point near Oxford where I have seen ground ice form, it may well do so.

[ I suspect there is another physical factor at work here. I guess there comes a point where almost freezing water does not freeze because it is moving. The gravel would offer many tiny 'shelters' between the stones in which the water would be relatively still and perhaps that is where the crystallisation started?
One would be interested to hear from a real physicist about this ... ]

1818: Walks in Oxford: By W. M. Wade 1818 -

A rather curious circumstance in the natural history of this river is its always freezing first at the bottom, whence the masses of ice as they are formed rise to the top.

1791: Samuel Ireland in his Picturesque Views on the Thames writes, of Buscot -

REMARKING that all the watermen, and persons concerned in the navigation, have an idea, and boldly assert, that the river, in this vicinity, freezes first at the bottom; and that they frequently find icicles and congelations adhering to the keels and bottoms of their boats, when there is no appearance of ice on the surface; and feeling myself not satisfied with this trite and vulgar opinion, I am induced to refer for a more philosophical and convincing proof of the assertion; when in Dr. Plott I find the following observation:
"That the water-men frequently meet the ice-meers, or cakes of ice, in their rise, and sometimes in the under-side including stones and gravel, brought with them ab imo [ latin - "from the bottom"];"
and he observes,
"it is consonant to reason, for that congelations come from the conflux of salts, before dispersed at large, is as plain as the vulgar experiment of freezing a pot by the fire ; and that induration and weight come also from thence, sufficiently appears from the great quantities of them that are always found in stones, bones, testaceous, and all other weighty bodies."
He likewise seems to credit the assertion of a person who once saw a hatchet casually fall overboard into the river, near Wallingford, which was afterwards brought up and found in one of these ice-meers.
As my author sometimes deals in the marvellous, I shall suspend any comment on these observations.

1813: The Beauties of England and Wales -

The congelation of the river Thames uniformly commences in the lowest places. The mass then formed rises (on a rude calculation) to about the middle of the water, where it presents, as in the streams of Germany, a resemblance to the partial consolidation of nuclei, or small hail.
A second mass then forms at the bottom ; the mass, centrally situated, rises to the surface ; and the new bottom, or ground ice, takes its place, and gradually (if permitted by a continued obstruction of sun-beams) mounts to the superior fabric, with which it speedily assimilates.
Dr. Plot accounts for this circumstance by supposing that the water of the Thames is more abundantly impregnated with salt than that of other English rivers ; and that, as salt naturally sinks to the bottom, and, as naturally, inclines to a principle of congelation, the formation of ice consequently takes place first at the greatest depth.