How is flow estimated?

EA SONNING Downstream graph
EA SONNING Upstream graph


from Environment Agency Guide 2012-2013

1910: Sonning in Thames Villages by Charles Harper.

Micro-Hydro Scheme

Waterpride Estates installed a 99kW single screw micro-hydro scheme in 2017 at Sonning Weir.
Enough energy is produced to offset the company's annual energy usage, making it the only carbon-neutral moorings business in the UK.
[See Sonning Mill Theatre for another Sonning hydro.]

Left bank lock, length: 156'1", width: 17'11"
1580:  Bishop - Sonning Weir belongs to Michael Blunte
1584:  Mention of the Weare Plot and Locke-heise
1632:  John Taylor complained the sill of the flash weir is too high
& 1721:  Lock, bucks, wares and fishery -

There are three water Wheeles & three Mills, besides one Mill which is used for grinding of course stuff when one of the other Mills doth not go, which belongs to Sonning Mills.  But the said ffour mills do not nor can't go together.  There is but one entire stream above the head of the mills but about ffour or ffive yards above the Mills there is an arrow head about ffour or ffive yards length in order to carry the water the sharper through the thoroughes of the mills for the service of two of these wheels, & from the said Arrow head the stream continues divided until it meets again below the way and eyotts leading to the mills which is about fforty or ffifty yards below the taile of the said mill.  The charge of keeping the engines and floodgates in repair is stated at fully £60 annually.

1770:  Act to establish Eight Pound Locks of which this was the highest.
1773:  Pound Lock opened.
1774:  Lock house built.
1780:  Lock Going into decay (It was built of fir)
1787:  Pound Lock rebuilt in oak

1794: Report of a survey of the river Thames between Reading and Isleworth ... John Rennie (the Elder)

At Sunning there is a tolerably good gauge wier for the floods, the water passed over it some inches deep.
The lock and stanch are under the management of the miller at Sunning Mill; the water stood four feet six inches deep on the upper sill, and two feet eleven inches on the lower sill of the lock, and was then five inches under the gauge mark, at Cotterell's Lock below.
The soundings shewed from three feet six inches to five feet of water in the Tail-cut, and does not much improve till below the ferry ; I was told the barges were often stopped in this short distance. The lower sill of the lock should be sunk eighteen or twenty inches, and the bottom of the reach as well as the Channel from the stanch should be ballasted to a proper depth in such places as may require it; namely about two hundred and twenty yards in length at the tail-cut of the lock, twenty-five yards at Sunning Bridge, and three hundred and thirty in two places, near the Roller above the ferry; a part of the shore on the Oxford side should be cut away to ease the entrance from the lock to the bridge.
A part of the ayt below the bridge should be pared off; the Berks shore should be lined with a strong piece of camshot to contract the width of the river, and force it more to the Oxford side. By this plan the channel will be confiderably straightened, and the river being contracted will enable it to maintain the depth of water required.
I would also advise the ferry to be done away, the towing path to be continued along the ayt, and a horse bridge to be made over the tail water of Sunning Mill. The towing horses may then cross the river at Sunning Bridge, instead of being ferryed over below.

1797:  Mill rebuilt at a cost of £1,178-8s.-6¾d.
1827:  Repairs to Pound Lock. During the stoppage the old flash lock was used.
1845:  James Sadler, bee keeper and poet, appointed lock keeper -

Is there a spot more lovely than the rest,
By art improved, by nature truly blest?
A noble river at its base is running,
It is a little village known as Sonning.

[ NB "Sonning" rhymes with "running" ]

1868:  Lock rebuilt

Lock Keeper James Sadler's advert in Henry Taunt's New Thames map, 1873

1880: Sonning Lock, Henry Taunt -

Sonning Lock, Henry Taunt, 1880
Sonning Lock, Henry Taunt, 1880
© Oxfordshire County Council Photographic Archive; HT2962

1881: George Leslie, "Our River"

[Sonning] lock itself is a nice new one, much celebrated for its roses and bees, which are both cultivated and attended to by Mr. Sadler the lock-keeper;  this old gentleman is a great character on the river, and possesses a variety of accomplishments.  He has paid great attention to the roses in his garden, having budded a number of the finest varieties, some of which may be seen blowing amongst the withies along the river banks, budded on to the original wild-rose stems wherever they happen to grow. 
Mr. Sadler is likewise a great bee-master and maker of bee-hives of a very ornamental character.  Besides being known as a rose grower and bee-master, he lays claim to celebrity as a poet, having written several Georgic strains on the care and management of bees and roses, and other verses which he calls “Summer Recreations”, one of which, No. 5, contains a capital description of a trip down the Thames from Oxford to Windsor.  This commences with a sentiment with which I most cordially agree:-

For strange and novel beauties
So widely people roam,
And often miss the loveliest spots
That lie about their home.
We aim not to disparage
Or weaken other claims,
But where can fairer scenes be found
Than on the river Thames?

[ Rhyme alert! But if "Sonning" rhymes with "running" just maybe "Thames" can rhyme with "claims" ? ]

He then goes on to describe the various places of interest passed on the trip, some of the descriptions of which are singularly neat and appropriate, as for instance that on Reading:-

From hence the town of Reading
Is just one field across,
'Mongst other things so widely known
For biscuits, seeds, and sauce.

[ And perhaps he really did pronounce "sauce" as "soss" (or possibly "across" as "acrorce") ! ]

1898/9:  Weirs reconstructed
1890:  Above Sonning Lock, Francis Frith -

1890:  Above Sonning Lock, Francis Frith
1890:  Above Sonning Lock, Francis Frith

1901: Sonning Weir -

1901:  Sonning Weir
1901:  Sonning Weir

1902: Sailing Barge near Sonning Church -

1902:  Sailing Barge
1902:  Sailing Barge moored near Sonning Church

1905:  Lock rebuilt
1916:  New Lock House
1917:  Below Sonning Lock, Francis Frith -

1917:  Below Sonning Lock, Francis Frith
1917:  Below Sonning Lock, Francis Frith

1951:  Sonning Lock, Salter's Steamer Majestic -

Sonning Lock, Salter's Steamer Majestic, 1951

1955:  Sonning Lock, Francis Frith -

1955:  Sonning Lock, Francis Frith
1955:  Sonning Lock, Francis Frith


Sonning Lock
Alaska (1883) in Sonning Lock in 1999, © John Eade

Chartering Alaska

Alaska was built in 1883 by Horsham & Co. of Bourne End, Buckinghamshire and she was subsequently purchased in 1887 from W.H. Barbrook of Walton-on-Thames for whom she had been built. Her new owners were the Oxford firm of Salter Brothers, who used her on the weekly return service from Oxford to Kingston and back. Passengers spent the day on the boat, enjoying the delightful scenery along the journey, and stayed ashore in different hotels each night.
In later years Alaska was used as a private party boat at Oxford.
Alaska served in the wartime Thames River Patrol, was then sold in 1942 for service further down the river with Joseph Mears and was laid up shortly afterwards.
After withdrawal, Alaska is reputed to have been poled from Kingston to Oxford by a new owner.
She settled in shallow water, was decked over and used as a boat hire pontoon. In 1974 she was rediscovered and identified by boat historians, ex-crew members and Lloyds. After being brought to a boatyard at Hurley, further research located her original engine at Kingston. Boat and engine were restored over a period of several years and a new boiler provided. In 1999, Alaska was acquired by Susanne & David Williams and leased to Thames Steamers for Thames charter work.
From 2006, Alaska is owned and operated by her skipper Peter Green.