Southampton - Geography

Geography

The geography of Southampton is influenced by the sea and rivers. The city lies at the northern tip of the Southampton Water, a deep water estuary, which is a ria formed at the end of the last Ice Age. Here, the rivers Test and Itchen converge. The Test—which has salt marsh that makes it ideal for salmon fishing—runs along the western edge of the city, while the Itchen splits Southampton in two—east and west. The city centre is located between the two rivers.

Town Quay is the original public quay, and dates from the 13th century. Today's Eastern Docks were created in the 1830s by land reclamation of the mud flats between the Itchen & Test estuaries. The Western Docks date from the 1930s when the Southern Railway Company commissioned a major land reclamation and dredging programme. Most of the material used for reclamation came from dredging of Southampton Water, to ensure that the port can continue to handle large ships.

Southampton Water has the benefit of a double high tide, with two high tide peaks, making the movement of large ships easier. This is not caused as popularly supposed by the presence of the Isle of Wight, but is a function of the shape and depth of the English Channel. In this area the general water flow is distorted by more local conditions reaching across to France.

The city lies in the Hampshire Basin, which sits atop chalk beds.

The River Test runs along the western border of the city, separating it from the New Forest. There are bridges over the Test from Southampton, including the road and rail bridges at Redbridge in the south and the M27 motorway to the north. The River Itchen runs through the middle of the city and is bridged in several places. The northernmost bridge, and the first to be built, is at Mansbridge, where the A27 road crosses the Itchen. The original bridge is closed to road traffic, but is still standing and open to pedestrians and cyclists. The river is bridged again at Swaythling, where Woodmill Bridge separates the tidal and non tidal sections of the river. Further south is Cobden Bridge which is notable as it was opened as a free bridge (it was originally named the Cobden Free Bridge), and was never a toll bridge. Downstream of the Cobden Bridge is the Northam Railway Bridge, then the Northam Road Bridge, which was the first major pre-stressed concrete bridge to be constructed in the United Kingdom. The southernmost, and newest, bridge on the Itchen is the Itchen Bridge, which is a toll bridge.