River Ash
Reach with wider banks, reeds and woodland close toShepperton Studios
The southernmost inner west-east line marks the end of the river, the rest is wholly in the same Borough shown.
Location
Country/Nation	United Kingdom
Region/Country	England
County	Surrey
City	Sunbury-on-Thames, Shepperton, Littleton51°24′25″N0°28′08″W / 51.407°N 0.469°W /51.407; -0.469, Laleham, Ashford, Staines-upon-Thames
Physical characteristics
Source	Sluice against lower River Colne
• location	Staines-upon-Thames,Spelthorne,England,United Kingdom
• elevation	14 m (46 ft)
Mouth	River Thames
• location	Sunbury-on-Thames andShepperton,Spelthorne,England,United Kingdom
• elevation	8.6 m (28 ft)
Length	10 km (6.2 mi)[1]
Width
• minimum	2 feet (0.61 m)
• average	6 feet (1.8 m)
• maximum	20 feet (6.1 m)
Depth
• minimum	0.5 feet (0.15 m)
• average	1.5 feet (0.46 m)
• maximum	5 feet (1.5 m)
Basin features
Progression	Colne—Ash—Thames
Artificial extra source: outflow of un-useable water from fresh waterworks

v t e River Ash and North Thames Reservoirs
Legend
Thames 1. 2. Intake of aqueduct (with sluice) Colne Brook County or Shire Ditch Wraysbury River Colne (feeder of the three above) Ash Pumping Station to3. &4. & 5. overflow sluice to the Ash Gravity-drained aqueduct  A308  road (River Ash under aqueduct)  A308  road Pumping Station to6. Ashford Treatment Works for 6.  A244  road Kempton Treatment Works (some water sent directly to below) 7.Grand Junction Reservoir Hampton Treatment Works 8. Thames

TheRiver Ash is a small, shallow river inSurrey,England. Its course of 10 kilometres (6.2 mi) is just outsideGreater London. Work has been carried out to re-align, clear and build up a small,Littletonhead of water and create twobackwaters. One backwater dates to the medieval period; the other to the 1990s. It flows as one of the sixdistributaries of theRiver Colne from the south ofStaines Moor immediately south of the Staines Bypass eastwards through the rest of theborough of Spelthorne before meeting theRiver Thames.

It is not navigable to craft and is rich in plant and insects, particularly reeds, diversesedges (many of which commonly called bulrushes),pond-skaters, amphibians and lepidoptera (moths and butterflies). It enhances the Ash Link Nature Reserve, Studios Walk woodland biodiversity site and two parks. It is recognised as a key ecological feature within its borough.^[1]

The river is adistributary of the Colne. It forms the traditional boundary ofStaines-upon-Thames, first withStanwell then withAshford.^{[n 1][2]} It then turns southward and splitsLittleton (specifically theQueen Mary Reservoir, then a thin nature reserve byShepperton Studios) fromLaleham. The Ash then resumes eastward. It is the northern limit of diminutive, near-squareShepperton Green — the western third of which was for centuries a southern outcrop (projection) of Littleton, and remains so in the Anglican church system.^[3] Eighteen-hole Sunbury Golf Course on high-landscaped former municipal wastelandfill then opposes a little ofShepperton across the banks. Then a farm ofGreen Belt straddles the river partly in outer lands ofSunbury-on-Thames. The river joins theThames, flowing gently into the Creek – a secondary weirstream of the Thames – facing a long residential island:Wheatley's Ait.^[4] It marks two streets' garden ends, many of which have built footbridges.^[5] The five urban centres in the borough are well over 500 m away, which has spared the Ash from pollution and supported its biodiversity. Three parks feature the river such as a long walk in Fordbridge Park, Ashford. Canoeists avoid the river when deep enough to canoe due to short barrages, extreme narrows and culverts.

In terms of flow of the distributaries, it is mid-ranked:

• flow exceeds:
  • Sweeps Ditch, Staines (perhaps no longer a distributary of the Colne since building works in the 1970s)
  • The long but ornamentalDuke of Northumberland's River
  • TheLongford River.^{[n 2]}
• flow normally dwarves:
  • the short final main Colne channel
  • theColne Brook
  • theRiver Wraysbury which just rejoins the Colne tens of metres from the Thames (so is more properly a later corollary) acting as a distributary.

Alluvium on gravel (save forLondon Clay outcrops, such asHarrow on the Hill,Hampstead Heath and theGrim's Ditch (Harrow)) is the soil setting of the north bank, west of theCity of London as far as theChiltern Hills.^[6] As to topsoil the river marks a divide between permeable shallow gravelly topsoil for many miles to the north and almost impermeablealluvium to the south. A very thin, agriculturally prosperous alluvial belt by theRiver Thames 0.6 miles (0.97 km) to 3 miles (4.8 km) away was caused by deposition from seasonal floods.^[7] This prevents for the whole course the rivers joining despite their proximity. As the gravel former terraces of the Thames very gently slope from north to south no abrupt halts to the water table exist nosprings arise and only modest interaction with theThames Basin'swater table. The sources are water from the Colne and run-off principally of a fresh water waterworks.

Water quality is ordinarily clean given improvements in the effluent treatment works along the quite populous Colne valley – for a low-gradient rivereutrophication anddeposition is moderate to low. The river is recognised as a key ecological feature within its Borough.^[1]

The Environment Agency measures the water quality of the river systems in England. Each is given an overall ecological status, which may be one of five levels: high, good, moderate, poor and bad. There are several components that are used to determine this, including biological status, which looks at the quantity and varieties ofinvertebrates,angiosperms and fish. Chemical status, which compares the concentrations of various chemicals against known safe concentrations, is rated good or fail.^[8]

Water quality of the River Ash in 2019:

Ashford gains its name from the river, forming the southern limit of all but its east half (ex-manordemesne andCommon). Relevant maps date to medieval times, showing course changes, some clearly man-made. The earliest at close resolution recounts various channels byShepperton Studios (Littleton Manor demesne), commissioned by the Lord of Shepperton Manor, two miles to the south.^[10] This refers to the monks of Westminster, who caused the local widening into heads of water as fish "pond"s.^[11][10]

Since 1910 the ex-Metropolitan Water Board'sStaines Aqueduct resembles the western 2.8 miles (4.5 km) of the Ash. It takes water from theThamesmuch further west to works atHanworth andHampton. To cross this andmeander, the river is in aculvert next to: Birch Green; Shortwood Allotments; andQueen Mary Reservoir.

The mid-course was shifted a little west to make way for theQueen Mary Reservoir inLittleton. A slight trace of the original course is near the reservoir's pumping station.

In the early 1960s, the outflow (source) from the Colne was moved back south.^[2] Further east; 100 metres is diverted to make way for the Staines Bypass(theA30). It then flows underground for 270 metres beneath the Crooked Billet roundabout.^[12]

Short residential streets in north-easternStaines upon Thames were flooded inFebruary 2014. At least 80 homes reported internal, outhouse or grounds flooding to the Environment Agency. Causes were complicated by the interweavingof an aqueduct which overflowed and various sluices; one found to be inadequate, another not best-operated.

A precedent for the river was in 1947 when flooding was widespread in the Thames Valley.^{[n 3]}

Upgrade of the fresh water treatment works at Ashford Common (1994–95) byThames Water Utilities caused greater steady outflow east of theM3. This heightened flood risk to properties abutting in Shepperton. Public budget work then arose, the River Ash Flood Alleviation Scheme of theEnvironment Agency. Deep holding troughs exist before the works run-off discharge and in Sunbury Golf Course a relief channel exists, bridged twice, built in January to May 1995 for £450,000.

Squires Bridge is a long two-arch bridge which has substantialneat (ashlar)stone-dressings, such as seven balusters across six lightly recessed stone panels, each side, each arch. It hasstatutory protection and recognition in the initial starting category (Grade II). It was built in about 1870, partly by commission of the Wood family whose Manor House, standing at today'sShepperton Studios, had a costly fire in 1874.^[13] Its central newel (pilaster) as to its outer, upstream side has a coat of arms with three swords, not the family's which was that of a bull, instead that ofMiddlesex.^[14]

Ash Link Local Nature Reserve, the first nature reserve in Spelthorne, was opened by the Mayor of Spelthorne in June 2012. It is managed by volunteers from Spelthorne Natural History Society and subgroup of its Friends in partnership with the Borough who own the land. It is in Shepperton, either side of theM3 as Splash Meadow in the south-east and Nutty Wood to the north-west.^[1]

The Reserve is linked by a large footbridge and has a variety of wildlife, mixed woodland, wildflower glades, ponds and the river. Conservation over the years has helped to increase the biodiversity of the area and as well as monitoring and recording the wealth of species; the volunteers continue to enhance the site for the benefit of the wildlife and enjoyment of the public.^[1]

In 2017 the Ash Link Local Nature Reserve was awarded a Gold Medal in the 'South and South East in Bloom' competition run by the Royal Horticultural Society; the next year the Friends received the 'Queen's Award for Voluntary Services.'^[1]

On the edge of Shepperton Studios (the Littleton "new" manor house estate), Studios Walk is a strip of Ash-side habitat. A surfaced path runs from west to east ends offering easy access and viewpoints over the river, unsurfaced paths also exist.^[1]

The woodland onsite is ecologically important thanks to numerous veteranoaks which promote a vast array of invertebrates. An oak tree can support 100 times the invertebrate abundance ofsycamores.^{[citation needed]} which, in turn, sustain bats, mice and squirrels. The rough bark and natural crevices that appear over time make ideal roosting. The natural progression of woodland into dead wood make the site an ideal habitat forstag beetles, iconic insects requiring large sections of dead wood to feed and for the development of larvae.^[1]

Kingfishers often are seen at these zones using the river as a foraging corridor. The marginal and in-channel habitat along with the sections of still water also offers ideal refuge for amphibians.^[1]

In 2016 a project was undertaken alongside the Environment Agency which formed part of the ColnCAN's "Weir today: gone tomorrow" programme. The works were the notching of a weir, installation of a new control structure and restoring a relic channel to serve as a by-pass channel to the main weir. The principal aim being to improve fish passage. About 600 metres was restored to provide favourable flow variations and enhanced aquatic and terrestrial habitat for a broad range of species.^[1]

• List of rivers in England
• Tributaries of the River Thames
• River morphology

Notes

References

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