Теміз өзенінің саласы: Уэндл өзені

Tributary of the River Thames, England

The River Wandle is a right bank tributary of the River Thames in south London, England. With a total length of about 9 mile (14 km), the river passes through the London boroughs of Croydon, Sutton, Merton and Wandsworth, where it reaches the Thames. A short headwater – the Caterham Bourne – is partially in Surrey, the historic county of the river's catchment. Tributaries of the Wandle include Carshalton Ponds and Norbury Brook. The Wandle Trail follows the course of the river from Croydon to Wandsworth.

The name is thought to derive from a back formation of Wandsworth ( meaning Wendle's Enclosure).

In the pleistocene before the carving of the Mole Gap, water lapped the north of the area between the North Downs and Greensand Hills known as the Vale of Holmesdale taking the Caterham or Coulsdon Bourne routes, to form the much less deep Merstham Gap, a wind gap. In more recent times, precipitation on the local central, small section of the long escarpment percolates through the chalk and reappears as springs in central Croydon, Beddington, and Carshalton. The occasional stream, known as the Bourne, which runs through the Caterham valley (and Smitham Bottom in Coulsdon) is a source of the River Wandle but only surfaces after heavy rainfall. A series of ditches and culverts carries the water from Purley to Croydon. For many centuries the River Wandle rose from springs including the garden of Blunt House, South End, Croydon and Brighton Road to enter and flow through the Haling neighbourhood in the south of Croydon. It ran along Southbridge Road and upon reaching Old Town it reached a maximal 20 feet (6 m) across and began to divide into smaller channels. The grounds of the Old Palace and Scarbrook Hill had springs engineered with ponds, streams and canals where fish swam, especially trout. Over the years, it became renowned for its fish, and is mentioned in works such as William Camden's Britannia (1586) and Izaak Walton's The Compleat Angler (1653). Lord Nelson would fish in its waters, leading his mistress, Lady Hamilton, to rename the Wandle, as it flowed through her garden, the "River Nile", in Nelson's memory. The Wandle then flowed through Pitlake and on through two marshy fields – Froggs Mead and Stubbs Mead – drained to form Wandle Park in 1890. Local springs were used to form a boating lake in the park, but frequent drying up problems led to the lake being filled in and the river was culverted in 1967. In 2012, the Wandle was restored to the surface in Wandle Park. From there, the river continues underground, through where the gas works used to stand, under the Purley Way road past Waddon Ponds and appears on the surface at Richmond Green road, where a small green buffer to its north acts as the green after the footpath at the end of Mill Lane in Waddon, Croydon. For part of its length, the Wandle forms the boundary between the London Boroughs of Croydon and Lambeth and, further downstream bounds Merton and Wandsworth. Shortly before reaching the Thames the navigable Bell Lane Creek splits from the river, rejoining close to the confluence. Localities adjoining the river and its mentioned main tributaries include: Croydon, Waddon, Beddington, Wallington, Carshalton, The Wrythe, Hackbridge, Mitcham, Ravensbury, St Helier, Morden, Merton Abbey, Colliers Wood, South Wimbledon, Summerstown, and Wandsworth. Honeywood Museum, in Carshalton Village, includes displays and an interactive map about the River Wandle and its influence on the life of the area.

Rain falling on part of the North Downs mainly filters through a thin topsoil into chalk and emerges on the spring line and in gentle ravines carved by water erosion. At the top of the catchment, the Wandle has four main headwaters historically noted as winterbournes — streams which only flow when the water table is high. The Liberty print works (latterly Merton Abbey Mills) and Merton Board Mills dominated the riverscape with the board mills being demolished in the 1990s (the site was redeveloped into a Sainsbury’s Savacentre). Local concentration of heavy industry resulted in multiple leats being cut during the 18th century; a remnant of the old courses, the Pickle, is two ditches, one running beneath Liberty Avenue. The former leat has become the main river next to Merton Abbey Mills craft village. Clean ups of the Wandle have improved the water quality dramatically, leading to a return of the river's brown trout. This improvement in water quality has also seen other fish thrive with stocks of chub, roach and dace all flourishing once again with the most popular angling spots being in Hackbridge and Colliers Wood.

A stretch of the river between Trewint Street and Plough Lane in Merton has been designated as the Lower Wandle Local Nature Reserve (LNR). It is lined by mature trees and patches of grassland. South of the Lower Wandle, an area of wetland between the River Wandle and the Wandle trail is the Wandle Meadow Nature Park LNR. Another LNR adjacent to the Wandle is the Wandle Valley Wetland in Carshalton. In 2017, a new nature reserve was created in Bell Lane Creek at the confluence of the Wandle and the Thames, by removing a half tide weir that had been installed in the 1980s. This had been built as the first part of a project to create a marina, however it had ceased to work some years previously. Restoring it would allow the tide to clear out silt and restore a natural tidal river. In addition, a section of the Thames river wall was lowered as part of the Wandsworth Riverside Quarter residential development, to allow reeds and vegetation to develop and provide a more natural sloping embankment. As part of the project, layers of contaminated sediment were dredged from the site, to restore a gravel bed and restore a wildlife habitat measuring roughly a hectare in size.

In 2007, Sodium hypochlorite was accidentally flushed into the Wandle from Thames Water's Beddington sewage works. The chemical was being used to clean its tertiary treatment screens. Its use is permitted if captured ("re circulated") for further treatment. The discharge killed over 2,000 fish of various species. The sewerage undertaker failed to notify the Environment Agency – its site manager thought it was minor. The company apologised; it offered to meet local angling clubs and the Wandle Trust to discuss restocking and long term support for the Trust's work. The regulator fined the provider £125,000 and legal costs. In 2009 it was the greatest penalty for a one day unlawful discharge into controlled waters. In 2010 a High Court judge found the fine was under the statutory rules governing pollution penalties "manifestly" excessive, reducing it to £50,000, noting Thames Water had donated £500,000 to clean up the river.

The predominant geology of the south part is chalk interspersed with flint and narrow alluvial gravel beds in the south. London clay overlaid with patches of gravel topped by deeper humus forms the north; the top soil, tempered by the chalk beneath is less acidic where still seasonally turned in the south. The river has since the 18th century been largely terraformed with tributary artificial channels (becoming surface water drains) and runoff ditches. It has its relatively few underground (culverted) stretches; these are in Croydon.