Question: What is the name of the river that had a bridge in the capital of Britannia Superior?

Context articles: Blestium
Londinium
Caer Gybi (fort)
Caersws Roman Forts
Britannia Superior
Cardiff Roman Fort
Burrium
Venta Belgarum
Alabum
Rufinus (Roman governor)

Blestium (also Blestio in the Antonine Itinerary (Iter XIII)) was a small fort and iron working centre in the Roman province of Britannia Superior, part of Roman Britain.
 It has been identified with the site of the later town of Monmouth in south east Wales, located adjoining the confluence of the River Monnow with the River Wye.
 A plaque on the local bank records its position.
Londinium was a settlement established on the current site of the City of London around  43.
 Its bridge over the River Thames turned the city into a road nexus and major port, serving as a major commercial centre in Roman Britain until its abandonment during the 5th century.
Caer Gybi was a small fortlet in Roman Wales in the Roman province of Britannia Superior.
 Its name in Latin is unknown.
 Today it stands at the centre of Holyhead in the Welsh county of Anglesey.
 Holyhead is named "Caergybi" in Welsh, after the fort.
The Caersws Roman Forts were two forts (Latin: "castra" ) in what later became the Roman province of Britannia Superior.
 Their remains lie beneath and adjacent to Caersws in Powys, Wales.
Britannia Superior (Latin for "Upper Britain") was one of the provinces of Roman Britain created around  197 by Emperor Septimius Severus immediately after winning a civil war against Clodius Albinus, a war fought to determine who would be the next emperor.
 Albinus was the governor of Britannia during that civil war.
 Severus divided the pre-existing province of Britannia into two parts, the other being Britannia Inferior to the north with its capital at Eboracum, or modern York.
 Britannia Superior was the southern province of the two, with its capital at Londinium, or what is today London.
 Epigraphic evidence has shed some light on the extent of Upper Britain and it encompassed all of what is now Southern England as well as Wales and East Anglia.
 However, the official boundary between Britannia Superior and Inferior is still unclear.
 Most information that is gathered for this region during this time period from about the 2nd to the 3rd century is from inscriptions left upon pots, walls, and letters written by the citizens and soldiers.
Cardiff Roman Fort was a coastal fort in the Roman province of Britannia Superior, of which Roman Wales was a part.
 Its original Latin name is uncertain.
 Its remains are incorporated into Cardiff Castle in the modern capital city of Wales.
Burrium was a legionary fortress in the Roman province of Britannia Superior or Roman Britain.
 Its remains today lie beneath the town of Usk in Monmouthshire, south east Wales.
Venta Belgarum was a town in the Roman province of Britannia Superior, the civitas capital of the local tribe, the Belgae, and which later became the city of Winchester.
 The name comes from Common Brittonic "*Uentā", meaning "town, place", plus the Latin genitive plural "Belgarum" "of the "Belgae" (tribe)".
Alabum was a fort in the Roman province of Britannia Superior, of which Roman Wales was a part.
... Rufinus is the fragment of the name of a governor of Britannia Superior, a province of Roman Britain probably some time during the early third century AD.
 He may have been the same man as Aulus Triarius Rufinus who was suffect consul around 210, although Quintus Aradius Rufinus who was consul ten or fifteen years later is another possibility.