River Ash, Surrey
|This article does not cite any references or sources. (December 2009)|
The River Ash runs along many people's back gardens, including Old Charlton Road (pictured).
|City||Shepperton,Coordinates: Ashford, Staines-upon-Thames|
|- location||Staines-upon-Thames, Spelthorne, England, United Kingdom|
|- location||Lower Sunbury, Spelthorne, England, United Kingdom|
|Length||10.6 km (7 mi)|
The River Ash is a small river in Surrey, England and its course of some 10 km or 6 miles is just outside Greater London. The course of the river has been much influenced by human action. It flows from the River Colne, just south of Staines Moor, eastwards through the borough of Spelthorne, running through the towns of Staines-upon-Thames, Ashford and Shepperton before joining the River Thames in the creek behind Sunbury Lock at Sunbury. It goes through many back gardens in Old Charlton Road, Shepperton.
There are maps dating back to medieval times documenting the changes made to the course of the river by man. The earliest one shows the history of the Shepperton Studios site, more particularly Shepperton Manor. This refers to the monks of Westminster, who, it is suggested, may have done some widening still visible today.
In 1910 the Metropolitan Water Board built the Staines Aqueduct to supply water from the River Thames at Hythe End to its works at Sunbury. This meant that the river was now in a siphon[clarification needed] at three locations: Birch Green and Shortwood Allotments as well near the Queen Mary Reservoir at Laleham.
Shortly after this, the River Ash was diverted to make way for the Queen Mary Reservoir in Laleham. Parts of the original course can still be seen near the Laleham Intake and Pumping Station.
In the early 1960s, the outflow from the River Colne, where the River Ash starts, was moved some metres south and some 100 metres of its length was diverted to make way for the Staines Bypass (the A30) . Here it flows underground for 270 metres beneath the Crooked Billet roundabout.
Flooding and alleviation 
The most recent serious flood on the River Ash was in 1947, when homes and roads were severely affected by flood waters. This was not due to the flood prevention methods on the River Ash but to those on the River Colne, as well as high water levels on the River Thames.
More work has been carried out recently under the River Ash Flood Alleviation Scheme. A major upgrade of the water treatment works at Ashford Common was started by Thames Water Utilities during 1994 and 1995, resulting in increased flow and flood risk at properties along Old Charlton Road, Shepperton and Heriden Way, as the works discharges to the lower River Ash near the M3. Consequently, a flood relief channel was suggested. This was built during the first five months in 1995 and cost a total of £450,000.
See also 
|Next confluence upstream||River Thames||Next confluence downstream
|River Wey (south)||River Ash, Surrey||Longford River (north)|