River Severn

The River Severn is the longest river in Great Britain, with a length of. It is also the river with the most voluminous flow of water by far in all of England and Wales, with an average flow rate of at Apperley, Gloucestershire. It rises in the Cambrian Mountains in mid Wales, at an altitude of, on the Plynlimon massif, which lies close to the Ceredigion/Powys border near Llanidloes. The river then flows through Shropshire, Worcestershire and Gloucestershire. The county towns of Shrewsbury, Worcester and Gloucester lie on its course.
The Severn's major tributaries are the Vyrnwy, the Tern, the Teme, the Warwickshire Avon, and the Worcestershire Stour.
By convention, the River Severn is usually considered to end, and the Severn Estuary to begin, after the Prince of Wales Bridge, between Severn Beach in South Gloucestershire and Sudbrook, Monmouthshire. The total area of the estuary's drainage basin is. That figure excludes the area of the River Wye and the Bristol Avon, both of which flow into the Severn Estuary. The estuary discharges into the Bristol Channel, which opens into the Celtic Sea and from there into the Atlantic Ocean.

Etymology and mythology

Celtic Root

An etymology has been proposed, which signifies that 'Severn' is an anglicised version of an ancient Celtic phrase signifying 'a gap ', referring to the estuary.

Romano-British name

The name Severn is thought to derive from a British word sabrinā, possibly from an older form *samarosina, meaning "land of summertime fallow".
During the Roman occupation the Severn was known by the Romano-British Latin name Sabrina.

Name legacy

's 1634 masque Comus makes Sabrina a nymph who had drowned in the river.
In Shrewsbury, there is now a statue of Sabrina in the Dingle Gardens at the Quarry, as well as a metal sculpture erected in 2013.
There is a different deity associated with the Severn Estuary: Nodens, represented as mounted on a seahorse, riding on the crest of the Severn bore.

Welsh name

The Welsh form of the name is Afon Hafren first recorded in the 12th-century Historia Regum Britanniae. The Old Welsh form of the name Habren was recorded c.800.
Documented history of the Welsh name:

Habren c.800.
Hauren c.1170.
hahafrenn, 12th century.
Dyffrin hawren, mid 13th century.

The toponym for Habren might be:

High prow of a ship.
High prow of a wave.
English name

The English form of the name is derived from Old English Sæfern. However the name is also influenced by English dialect seave hence the origin of the name Seaverne recorded in the 16th–17th century.
Common club-rush prefers to grow in shallow water such as that found in ponds, streams and river margins. The Hwicce people used the club-rush growing along the banks of the River Severn to make wicker baskets.

Name history

The name history shows evidence of Scandinavian influence:

Name	Year	Period	Influence
Sæferne	894	Viking Age	Old English sæfôr – "seafarer".
Saverna	1086	Norman Conquest	English dialect seave – "sedge, rush".
Severne	1205	13th century	English dialect seave
Sephern	1479	15th century	Old Norse sef – "sedge, rush".
Seaverne	1584	16th century	English dialect seave
Seaverne	1677	17th century	English dialect seave
Severn	1836	19th century

Viking age

In the Summer of 893 a coalition of all of the Danish armies in England made a determined attempt to annex western Mercia to Danish Mercia. The Anglo-Saxon Chronicle recorded an account of the Battle of Buttington, and included this description of the route taken by the Danes:

"... Foron þa up be Temese oþþæt hie gedydon æt Sæferne, þa up be Sæferne.

Seafarer

The name Sæfern might be related to:

The Sea.
Middle English faren – "travel".
Old Norse sær – "the sea, ocean".
Old Norse fara – "to fare, to travel".
The Old Norse personal name Sæfari – "Seafarer".

The Old Norse name Sæfari lives on as the name of the Dalvík – Grímsey ferry in Iceland.

Geography and geology

The River Severn's current form is the result of a multi-million year history and complex underlying geology but is in part the result of glaciation during the last ice age in the Pleistocene epoch of the Quaternary period. Within Wales, the river runs through a landscape formed in Ordovician and Silurian rocks. As it enters the Shropshire Plain, these lower Palaeozoic rocks are replaced by Permian and Triassic age strata though largely unseen beneath a thick cover of Quaternary deposits. Certain stretches also run across Carboniferous strata as at Shrewsbury and for much of the distance between Ironbridge and Bewdley. Permo-Triassic bedrock then continues until the Severn moves intermittently onto the Jurassic outcrop from Tewkesbury southwards. Only in the SSW-NNE aligned valley either side of Welshpool is there any obvious relationship to geological structure where the valley follows the lines of the Severn Valley Fault Belt. For much of the rest of its course it runs directly across geological structures.
It was first proposed in the 1900s that the former northerly course of the upper Severn was disrupted during the course of the ice age by the blocking of its access to the Irish Sea through Cheshire causing a large lake to develop across much of Shropshire. It was supposed that this lake, named as Lake Lapworth, overtopped its southern margin and rapidly cut down to form the Ironbridge Gorge providing the Severn with a southerly exit to the sea as remains the case today. An alternative theory which has gained favour in recent years does away with Lake Lapworth, suggesting that the upper Severn flowed beneath the icesheet in a bedrock hollow known as the Severn Trench eastwards from Melverley to the Ironbridge Gorge. It is possible that the trench and gorge were cut over successive ice ages.

Tributary rivers

Over its length, there are a large number of tributaries, but the three largest feeding the non-tidal river are the Vyrnwy, the Teme and the Warwickshire Avon. The Wye, the Bristol Avon and the Usk all flow into the estuarine section of the Severn. The main tributaries are described in sequence below.
The first tributary of significance is the Afon Dulas, joining from the south immediately upstream of Llanidloes, with the Afon Clywedog joining in the town. The Afon Cerist, bolstered by the Afon Trannon, and the Afon Carno join as left bank tributaries immediately upstream of Caersws. Mochdre Brook enters on the western edge of Newtown, followed by the Bechan Brook just northeast of the town. The Mule enters at Abermule, and the River Rhiw east of Berriew, followed shortly by the Camlad which rises above Churchstoke and by the Luggy Brook. The left bank Sylfaen Brook enters at Welshpool, and the Bele Brook via the New Cut east of Arddlin.
The River Vyrnwy, which begins at Lake Vyrnwy, flows eastwards through Powys, gathering the waters of the Banwy, Cain and Tanat, before forming part of the border between England and Wales, and joining the Severn near Melverley, Shropshire. The River Perry joins on the left bank above Shrewsbury, while both the Rad Brook and the Rea Brook, which flows northeast from its source at Marton Pool near the Welsh border, join the Severn within the town. The left bank tributary, the River Tern, after flowing south from Market Drayton and being joined by the River Meese and the River Roden, meets the Severn at Attingham Park.
The River Worfe joins the Severn's left bank just above Bridgnorth, before the Mor, Borle and Dowles brooks join on the opposite bank over the next few miles, the last-named draining Wyre Forest. The River Stour rises in the north of Worcestershire in the Clent Hills, near St Kenelm's Church at Romsley. It flows north into the adjacent West Midlands at Halesowen. It then flows westwards through Cradley Heath and Stourbridge, where it leaves the Black Country. It is joined by the Smestow Brook at Prestwood before it winds around southwards to Kinver, and then flows back into Worcestershire. It then passes through Wolverley, Kidderminster and Wilden to its confluence with the Severn at Stourport-on-Severn. The Dick Brook, Shrawley Brook and Grimley Brook enter on the right bank before the River Salwarpe, which runs through Droitwich enters on the opposite bank.
The River Teme flows eastwards from its source in Mid Wales, straddling the border between Shropshire and Herefordshire; it is joined by the River Onny, River Corve and River Rea before it finally joins the Severn on the southern edge of Worcester. Bushley Brook joins just upstream of the confluence of the Warwickshire Avon with the Severn at Tewkesbury. One of several Avons, this one flows west through Rugby, Warwick and Stratford-upon-Avon. It is then joined by its tributary the River Arrow, before joining the Severn. The rivers Swilgate and Chelt also join the Severn's left bank, as do the Hatherley and Horsbere brooks, before it reaches Gloucester. The River Leadon enters the tidal West Channel of the Severn at Over, immediately west of Gloucester. The River Frome is the second significant tributary to enter the tidal stretch of the Severn, doing so at Framilode. Bideford Brook drains the easternmost part of the Forest of Dean, entering the Severn estuary east of Blakeney. On the opposite bank the flow of the River Cam is usurped by the Gloucester and Sharpness Canal before reaching the estuary. The Lyd enters the west bank of the estuary at Lydney Harbour, opposite the place where Berkeley Pill carries the waters of the Little Avon River into it. The final tributary before the Severn Bridge is the collection of streams which enter via Oldbury Pill.
The River Wye, from its source in Plynlimon in Wales, flows generally south east through the Welsh towns of Rhayader and Builth Wells. It enters Herefordshire, flows through Hereford, and is shortly afterwards joined by the River Lugg, before flowing through Ross-on-Wye and Monmouth, and then southwards where it forms part of the border between England and Wales. The Wye flows into the Severn estuary south of the town of Chepstow.
The Mounton Brook and Nedern Brooks enter on the Monmouthshire side between the two motorway crossings. The Port of Bristol is on the Severn Estuary, where another River Avon flows into it through the Avon Gorge. The River Usk and the Ebbw River flow into the Severn Estuary at Uskmouth just south of Newport.