The Pinn is a suburban, outer west

London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...

river. It has dendritic headwaters, the furthest is considered its sourcein

Harrow Weald Harrow Weald is a suburban district in Greater London, England. Located about north of Harrow, Harrow Weald is formed from a leafy 1930s suburban development along with ancient woodland of Harrow Weald Common. It forms part of the London Boro ...

. Its

confluence In geography, a confluence (also: ''conflux'') occurs where two or more flowing bodies of water join to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); o ...

with

Frays River Frays River is a semi-canalised short river in England that branches off the River Colne at Uxbridge Moor and rejoins it at West Drayton. It is believed to be a mainly man-made anabranch north of the confluence with the River Pinn to feed wat ...

makes it a

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainage ...

of the

Colne Colne () is a market town and civil parish in the Borough of Pendle in Lancashire, England. Located northeast of Nelson, north-east of Burnley, east of Preston and west of Leeds. The town should not be confused with the unrelated Colne Val ...

. It is one of three principal rivers wholly in the historic county of

Middlesex Middlesex (; abbreviation: Middx) is a Historic counties of England, historic county in South East England, southeast England. Its area is almost entirely within the wider urbanised area of London and mostly within the Ceremonial counties of ...

Route

The river runs through

Pinner Pinner is a London suburb in the London borough of Harrow, Greater London, England, northwest of Charing Cross, close to the border with Hillingdon, historically in the county of Middlesex. The population was 31,130 in 2011. Originally a med ...

, the northern halves of

Eastcote Eastcote is a suburban area in the London Borough of Hillingdon, in northwest London. In the Middle Ages, Eastcote was one of the three areas that made up the parish of Ruislip, under the name of Ascot. The name came from its position to the e ...

and

Ruislip Ruislip ( ) is an area in the London Borough of Hillingdon in West London, and in the historic county of Middlesex. Ruislip lies west-north-west of Charing Cross, London. The manor of Ruislip appears in the Domesday Book, and some of the ear ...

: the latter may be a notable rise-lip of land as 17th century maps often have the place name but likely derives from "rush leap" from the local width of the river. It then runs through

Ickenham Ickenham is an area in Greater London, forming the eastern part of Uxbridge and within the London Borough of Hillingdon. While no major historical events have taken place in Ickenham, settlements dating back to the Roman occupation of Britain ...

and on to

Uxbridge Uxbridge () is a suburban town in west London and the administrative headquarters of the London Borough of Hillingdon. Situated west-northwest of Charing Cross, it is one of the major metropolitan centres identified in the London Plan. Uxbrid ...

, where it passes through the former grounds of

RAF Uxbridge RAF Uxbridge was a Royal Air Force (RAF) station in Uxbridge, within the London Borough of Hillingdon, occupying a site that originally belonged to the Hillingdon House estate. The British Government purchased the estate in 1915, three years ...

and

Brunel University Brunel University London is a public research university located in the Uxbridge area of London, England. It was founded in 1966 and named after the Victorian engineer and pioneer of the Industrial Revolution, Isambard Kingdom Brunel. In June 1 ...

. The Pinn continues on to Pield Heath and Cowley, passing under the

Grand Union canal The Grand Union Canal in England is part of the British canal system. It is the principal navigable waterway between London and the Midlands. Starting in London, one arm runs to Leicester and another ends in Birmingham, with the latter st ...

before joining the

, an

anabranch An anabranch is a section of a river or stream that diverts from the main channel or stem of the watercourse and rejoins the main stem downstream. Local anabranches can be the result of small islands in the watercourse. In larger anabranches, th ...

of the Colne, at

Yiewsley Yiewsley ( ) is a large suburban village in the London Borough of Hillingdon, England, 2 miles (3 km) south of Uxbridge, the borough's commercial and administrative centre. Yiewsley was a chapelry in the ancient parish of Hillingdon, Middl ...

."Cowley: Introduction"
''A History of the County of Middlesex: Volume 3: Shepperton, Staines, Stanwell, Sunbury, Teddington, Heston and Isleworth, Twickenham, Cowley, Cranford, West Drayton, Greenford, Hanwell, Harefield and Harlington'' (1962), pp. 170-172. Institute of Historical Research, University of London. Retrieved 27 October 2008. During the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

only, the Pinn was dammed near

High Street for water for putting out fires from air raids. The middle and lower thirds of the course are between the Colne and Crane, all flowing south, thus making up

parallel drainage In geomorphology, drainage systems, also known as river systems, are the patterns formed by the streams, rivers, and lakes in a particular drainage basin. They are governed by the topography of land, whether a particular region is dominated by har ...

Celandine Route

This is a walk through woodland, meadows and parks. It finishes at the Grand Union Canal towpath parallel to the Fray's River anabranch of the Colne.

Connections

A short walk east along the

Slough Arm The Slough Arm is a short canal branch from the Grand Union Main Line to Slough in Berkshire (before 1974 in Buckinghamshire), England. It was originally opened to serve the brick-making industry. The last commercial traffic was carried in ...

of the

Grand Union Canal The Grand Union Canal in England is part of the British canal system. It is the principal navigable waterway between London and the Midlands. Starting in London, one arm runs to Leicester and another ends in Birmingham, with the latter st ...

connects. The Grand Union Canal towpath connects, linking in Brentford (east south-east), Watford and the Midlands (north), and the

Paddington Arm The Paddington Canal or Paddington Arm of the Grand Union Canal is a canal to Paddington in central London, England. It runs from the west of the capital at Bull's Bridge in Hayes. Little Venice — its only junction — is with the Reg ...

(central London, east).

Water quality

All local sewerage runs to the distant

Mogden Sewage Treatment Works Mogden Sewage Treatment Works is a sewage treatment plant in the Ivybridge (Isleworth), Ivybridge section of Isleworth, West London, formerly known as Mogden. Built in 1931–36 by Middlesex County Council and now operated by Thames Water, it is th ...

discharging its treated waters to the

Tideway The Tideway is a part of the River Thames in England which is subject to tides. This stretch of water is downstream from Teddington Lock. The Tideway comprises the upper Thames Estuary including the Pool of London. Tidal activity Depending on ...

. This spares the Pinn from the incident nitrogen, bleach (ammonia) and other chemical biohazards which many of its catchment homes and business use and/or discharge. The Pinn's flow is weak save for after moderate or heavy rain. Worn tyre and motor oil run-off is from some roadside drains at biohazardous levels, particularly below the

A40 road A4 most often refers to: *A4 paper, a paper size defined by the ISO 216 standard, measuring 210 × 297 mm A4 and variants may also refer to: Science and mathematics * British NVC community A4 (''Hydrocharis morsus-ranae - Stratiotes aloide ...

which is a trunk route of six lanes at this point (this becomes the

M40 motorway The M40 motorway links London, Oxford and Birmingham in England, a distance of approximately . The motorway is dual three lanes except for junction 1A to junction 3 (which is dual four lanes) a short section in-between the exit and entry slip-r ...

to the west) – about of this slopes down to the river.

Citations and footnotes

External links