River Itchen, Hampshire

Itchen
Alre (see tributary so-named)
The Itchen near Avington
Map of the River Itchen, in dark blue, and its principal tributary, the Alre, in grey. Canal sections of the Itchen Navigation in green.
EtymologyUnknown
Location
CountryEngland
CountyHampshire
CityWinchester Southampton
Physical characteristics
Source 
  locationsouth of New Cheriton, Kilmeston, Hampshire, England
  coordinates51°02′33″N 1°09′37″W / 51.0426°N 1.1603°W / 51.0426; -1.1603
MouthSouthampton Water
  location
Southampton, Hampshire
  coordinates
50°54′19″N 1°23′08″W / 50.9052°N 1.38565°W / 50.9052; -1.38565
  elevation
0 metres
Length26 miles (42 km) or unconventionally: 88 km (55 mi) (including all anabranches)
Basin size119.619 km2 (46.185 sq mi)
Discharge 
  locationRiverside Park, Bitterne Park
  average5.3 m3/s (190 cu ft/s)
  minimum1.75 m3/s (62 cu ft/s)14 August 1995
Discharge 
  locationHighbridge, Hampshire
  average5.4 m3/s (190 cu ft/s)
Discharge 
  locationEaston, Hampshire
  average4.3 m3/s (150 cu ft/s)
Basin features
Tributaries 
  left
  rightCheriton Stream

The River Itchen in Hampshire, England, rises to the south of New Alresford and flows 26 miles (42 km) to meet Southampton Water below the Itchen Bridge. The Itchen Navigation was constructed in the late 17th and early 18th centuries to enable barges to reach Winchester from Southampton Docks, but ceased to operate in the mid-19th century and is largely abandoned today.

The river is one of the world's premier chalk streams for fly fishing, amenable to dry fly or nymphing. The local chalk aquifer has excellent storage and filtration and the river has long been used for drinking water. Watercress thrives in its upper reaches.

Much of the river from its source to Swaythling is classified as a 748.5-hectare (1,850-acre) biological Site of Special Scientific Interest (SSSI), and a Special Area of Conservation, of which the 9-hectare (22-acre) Hockley Meadows nature reserve is a part. The Itchen estuary is part of the separate Lee-on-The Solent to Itchen Estuary SSSI.