River Mole, Surrey

The River Mole is a river in southern England, which rises in West Sussex near Gatwick Airport and flows north west through Surrey for 80 km (50 miles) to the River Thames near Hampton Court Palace. The river gives its name to the Surrey district of Mole Valley. The river has captured the imagination of several authors and poets, particularly since in very hot summers, the river channel can become dry between Dorking and Leatherhead, where it cuts through the North Downs (most recently in 1976). [ [http://www.pbase.com/john_cooper/image/46573612 River Mole at Leatherhead in 1976 photo - John Cooper photos at pbase.com ] ] In John Speed's 1611 map of Surrey this stretch of the river is denoted by a series of hills accompanied by the legend "The river runneth under". The river's name is unlikely to have derived however from this behaviour: The "Oxford Dictionary of English Place Names" suggests that "Mole" either comes from the Latin "mola" (a mill) or is a back-formation from "Molesey" (Mul's island). [AD Mills (1998) "Oxford Dictionary of English Place Names" (2nd ed.) OUP ISBN 0192800744] In medieval times the river was known as the Emlyn Stream.

Course

Catchment area

The drainage area of the River Mole is 512 km² and forms 5% of the River Thames catchment area above Teddington. Annually the catchment area receives 761 mm rain each year, the greatest average level of rainfall is 800 mm rain around Crawley. There is only one aquifer in the drainage basin, at Fetcham, which means that the majority of the water in the river is from surface drainage, particularly from Gatwick Airport and the urban areas of Horley and Crawley and that the flow rate responds rapidly to rainfall. [http://www.environment-agency.gov.uk/commondata/acrobat/mole_condoc_p1_1698235.pdf Mole CAMs Cover.qxd] ]

Upper Mole

The River Mole rises to the south of the West Sussex village of Rusper, initially flowing eastwards across the Wealden Clay. The first tributaries to join the young river drain the northernmost part of St Leonards Forest, between Horsham and Crawley, although much of that area lies within the catchment of the River Arun. After skirting the Crawley suburb of Ifield, the river turns northwards to run under the runway of Gatwick Airport in a culvert. The course of the Mole within the airport perimeter has been altered several times since commercial flights began in 1945, however the meanders visible on the 1839 tithe map on the 1.5 km stretch immediately north of the runway were reinstated in 1999, in a £1.2M project to facilitate airport expansion. [http://www.baa.com/assets//B2CPortal/Static%20Files/glsstnbltyrprt2002.pdf] http://www.tpsconsult.co.uk/tps/assets/pdf/profiles/gatwick_river_mole.pdf]

The Mole enters Surrey to the south of Horley, where it meets its first significant tributary, the Gatwick Stream, which drains Worth Forest to the southeast of Crawley. The river changes direction at this point to flow north as far as Sidlow and then west towards Brockham. The tributaries joining from the west are typically second order streams draining the arable land between Horsham and Dorking, those which join from the east are generally larger and drain the outcrops of greensand around Outwood and Nutfield.

Mole Gap

The Mole leaves the Wealden Clay at Brockham, flowing briefly across the greensand and gault clay, before turning northwards to cut a steep-sided valley (the Mole Gap) though the North Downs. The sudden change from impermeable Wealden Clay to permeable chalk and the increased gradient of the river (which drops 15 m in the six mile stretch between Brockham and Leatherhead, compared to 3 m in 12 miles between Horley and Brockham) allow the water table to drop below the bed of the river. Water is able to flow out of the river through swallow holes in the bed and banks, decreasing the volume of water carried in the river channel. The course of the river north of the village of Westhumble was partially straightened when the Epsom to Horsham railway was built in 1837, with the removal of a small meander. [Shepperd R (1982) The Manor of Wistomble in the Parish of Mickleham "Westhumble Association"] The meander was reinstated in 1997, in an attempt to create a local nature reserve, although it has since become blocked by silt. The entirety of the Mole Gap lies within the Surrey Hills Area of Outstanding Natural Beauty. [ [http://www.surreyhills.org Surrey Hills ] ]

Lower Mole

At Leatherhead, the Mole leaves the chalk and turns northwestwards to flow across impermeable London Clay towards Cobham. The water table rises at this point and much of the water which drained out of the channel through the chalk returns through springs in the riverbed. The aquifer at Fetcham is the only one in the entire catchment area. At Cobham the river changes direction again, flowing northwards, passing Esher to the west before splitting into two branches at the Island Barn Reservoir near Molesey: the northern (and smaller) branch continues as the River Mole and the southern branch is known as the River Ember.WE Foster WB Harris (1988) Flood Alleviation Scheme for the Lower River Mole "Proceedings of the Institution of Civil Engineers" 84 235-263] The two rivers flow either side of the reservoir, before flowing side by side in a north easterly direction, merging 400 metres before the confluence with the River Thames, on the reach above Teddington Lock. (For the purposes of the remainder of this article, the River Mole and the River Ember are treated as a single entity.)

Pre-Ice Age course

Prior to the last Ice Age, the River Thames followed a more northerly route to the North Sea, from Reading via Marlow, Chorleywood, St Albans, Hertford and along the present Suffolk-Essex border. During this period, the Mole is thought to have merged with the River Wey near Byfleet and then flowed in a north-easterly direction via Richmond to meet the proto-Thames near Ware in Hertfordshire. (Today the Mole and Wey are less than 2 km (1.5 miles) apart at their closest point south of Esher.) During the mid-Pleistocene period (500 000 years before present), a large ice sheet built up across much of the East of England, reaching as far south as St Albans and Chelmsford, blocking the path of the proto-Thames. Glacial meltwater from the Anglian ice sheet, caused the Thames to divert southwards into the valley of the Mole-Wey river, thus adopting its present route through London. [Bridgland and Gibbard (1997) Quaternary River Diversions in the London Basin and the Eastern English Channel "Géographie physique et Quaternaire" 51 (3) 337-346]

Biodiversity

Amphibians

The Marsh Frog "Pelophylax ridibundus" (a non-native species introduced from Europe in the 1930s) is now commonly found in the upper Mole and its tributaries around Newdigate and Gatwick. There is no evidence that the presence of the frogs has had a deleterious effect on indigenous amphibians. [http://www.surrey-arg.org.uk/cgi-bin/SARG2ReptileSpeciesData.asp?Species=Marsh_Frog] A second non-native species, the Edible Frog ("Pelophylax kl. esculentus") was introduced to a site at Newdigate in the early 1900s. It has recently been recorded in tributaries of the River Mole at Capel and Brockham. [http://www.surrey-arg.org.uk/cgi-bin/SARG2ReptileSpeciesData.asp?Species=Edible_Frog]

Fish

The River Mole has the most diverse fish population of any river in England. [http://www.environment-agency.gov.uk/commondata/acrobat/fisheries_eng_765655.pdf] The Gatwick Stream is dominated by coarse fish such as brown trout, brook lamprey, and eel. In 2003, the River Mole at Meath Green was enhanced to create a gravel spawning area to encourage chub and dace in addition to roach. In the Mole Gap between Dorking and Leatherhead the river supports populations of chub, dace, barbel, brown trout. Both barbel and brown trout are extremely sensitive to water quality and pollution. Below Leatherhead the river has historically supported larger predatory fish including chub, perch, pike, and eels, however in recent years chub and eel numbers have begun to decline. North of Esher the old river channel is dominated by floating pennywort, a highly invasive weed, which cuts off all light to the river bed, reducing oxygen levels and resulting in a poor habitat for fish. The Ember flood relief channel has a diverse fish population, including chub, dace, roach, bleak, large pike and barbel. At the confluence of the Mole and the River Thames it is possible to catch brown trout and flounder. [http://www.environmentagency.net/commondata/acrobat/river__tidal__562842.pdf]

Invertebrates

The geographical distribution of many species of invertebrate in the river reflects the geology of the catchment area. Viviparid snails and water scorpions (of the genus "Nepidae") are commonly found where the river runs over the London Clay. Crayfish are common in areas associated with high alkalinity particularly around Brockham and the tributaries which run over the Wealden Clay provide an excellent habitat for stoneflies, caddisflies, fast swimming mayflies and riffle beetles. [Ruse LP (1996) Multivariate techniques relating macroinvertebrate and environmental data from a river catchment "Water Research" 30 (12) 3017-3024] The Beautiful Demoiselle ("Calopteryx virgo") disappeared from the River Mole during the 1960s owing to deteriorating water quality, but has since recolonised.http://www.surreybiodiversitypartnership.org/xwiki/bin/view/Wetland/ActionPlan] The White-legged Damselfly ("Platycnemis pennipes") is also found along the river and the Downy Emerald ("Cordulia aenea") is found between Box Hill and Leatherhead. [ P. Follett (1996) Mole Valley Natural History Audit: Survey of "Odonata" - Dragonflies and Damselflies ]

Plants

A nationally scarce species which is locally common on the River Mole is the Greater Dodder "Cuscuta europaea". [ [http://www.sshac.org.uk/swt1.pdf SWT.HAP.wetland ] ]

Mole Valley Corridor Local Nature Reserve

The stretch of river between Thorncroft Manor (1 km south of Leatherhead) and River Lane in Fetcham has been designated a Local Nature Reserve. [ [http://www.molevalley.gov.uk/index.cfm?articleid=2021 Mole Valley nature reserve] ] Although much of the surrounding land has been taken by residential and commercial development, this section of the Mole supports 20 different mammal species, 20 butterfly species and 15 species of dragonfly. The geology of the local area is complex, since the river leaves the chalk of the Mole Gap at this point and flows over gravel and clay, creating a patchwork of different habitats including scrub, woodland, hedges, banks, and meadows as well as the water itself. The river also provides a corridor for wildlife through the centre of Leatherhead. [ [http://www.molevalley.gov.uk/index.cfm?Articleid=1934 Mole Valley - River Mole corridor becomes local nature reserve ] ]

West End Common

The West End Common forms part of the Esher Commons, owned and managed by Elmbridge Borough Council. The River Mole forms the western boundary of the common, flowing past a steep sandy area known locally as "The Ledges". Plant species typical of ancient woodland are found in this area, including bluebells ("Hyacinthoides non-scriptus"), Marsh Marigolds ("Caltha palustris") and Golden Saxifrages ("Chrysosplenium" sp.). Large Bittercress ("Cardamine amara") and the non-native Himalayan Balsam ("Impatiens glandulifera") are also found along the river banks. [http://www.elmbridge.gov.uk/leisure/countryside/wildlife.htm?largetext=on]

Navigation

In March 1663, a bill was passed by the House of Commons, but was defeated in the House of Lords

"to make navigable or otherwise passable, divers Rivers from Greenstead [ East Grinstead ] , Arundell [ Arundel ] , Petersfield, Darkin [ Dorking ] and Farnham... to London."

In 1664, an act was passed by both Houses of Parliament to make the River Mole navigable from Reigate to the River Thames, but was never executed. [London's Lost Route to the Sea by PAL Vine] [http://www.iisg.nl/hpw/papers/law-bogart.pdf ] The only Surrey river to have been made fully navigable is the River Wey. The Mole is navigable for the 600 yards up to the confluence with the Ember where there is a private mooring facility.

wallow Holes between Dorking and Leatherhead

The underlying rock type in this part of Surrey is chalk and the water table lies permanently below the level of the riverbed.FH Edmunds (1943) Swallow holes and openings in the chalk of the Mole Valley "The London Naturalist" pages 2-7] This allows water to drain out of the river through swallow holes in the river bed and banks. At Leatherhead, the river leaves the chalk and flows across impermeable London Clay. It is at this point that the water table rises sufficiently, enabling the water to flow back into the main river channel.
In a survey in 1958, the geologist C.C. Fagg, identified twenty five active swallow holes between Dorking and Mickleham and classified them into four basic types:

1) Swallow holes at the bottom of depressions in the river bed.
2) Swallow holes in the bed of the river but on high spots near the banks [or on islands]
3) Swallows at varying levels in the vertical sides of the river... The openings into these are either into chalk or alluvium leading to chalk.
4) Swallows in depressions on the flood plain near to, but more or less detached from, the vertical banks. They are inaccessible to river water until it rises sufficiently to overflow into them.CC Fagg (1957) Swallow holes in the Mole Gap "The South-eastern Naturalist and Antiquary" 62 1-13]

Most swallow holes are only a few centimetres in diameter, are of the third type and are difficult to observe in times of normal or heavy river flow. Old holes, particularly those in the river bed (types 1 and 2) are susceptible to silting up and new holes are continually being formed. Fagg continues:

In 1948 [swallow hole] No. 2 could only be detected by water trickling between flints but in 1949, after the winter submergence, it was a gaping hole.

The local historian and Westhumble resident Ronnie Sheppard describes a hole of the fourth type, which he recorded in 1947:

...at the foot of Ham Bank where the Mole takes a sharp turn to the north; it was about two feet in diameter and the water flowed down in a clockwise direction as if out of a bath.Shepperd R (1982) "The Manor of Wistomble in the Parish of Mickleham: A local history" chapter 9 page 85]

A year later, Fagg surveyed the same hole:

At first it appeared that the river would have to rise to the level of the lip, before it could enter the pit containing the swallow, but water was found to enter at a lower level through a hidden channel in alluvium... Such a channel might be initiated by a moorhen or a burrowing animal. This channel was doubtless the original access to the swallow.

An article published in" The Times "in April 1936 describes a low lying area of approximately half an acre, lying alongside and connected to the river, between the Burford Bridge and the southernmost railway bridge. There were four or five groups of swallow holes (again of the fourth type) at this site "around which the water swirled before it poured into the depths below."

No. 1 comprises two big holes and several smaller areas round the brink; the southern measures across the top 80 x 80 ft. and is 10 ft. deep, the northern measures 70 x 70 ft.; No. 2 consists of two, 60 x 60 ft. and 30 x 30 ft. ; No. 3 is a straight down pipe 15 x 15 ft. and No. 4 is 90 x 88 ft. and 14 ft. deep." ["The Times" April 1936]

The A24 Mickleham Bypass was under construction at the time at which the article was written and it was decided to fill the holes with rubble to prevent the foundations of the new road subsiding. However this proved to be impractical and they were instead covered by concrete domes (up to 18 m in diameter) each fully supported by the surrounding chalk and provided with a manhole and access shaft to allow periodic indpections. A survey in the late 1960s showed that the alluvium in the largest swallow hole had subsided 1.5 m under the centre of the dome. [West and Dumbleton (1972) Some observations on swallow holes and mines in the Chalk "Quarterly Journal of Engineering Geology" 5 171-177]
Fagg (who was at the time a researcher at the Juniper Hall Field Centre) estimated that one swallow hole (of the first type) was able to carry 0.75 million gallons of water out of the river channel per day and that the daily average volume of the river at Dorking was 70 million gallons. As a rough estimate, the twenty five swallow holes which were active in 1957, were therefore able to reduce the flow of the river through the Mole Gap by approximately one quarter.
The author, Daniel Defoe (who attended school in Dorking and probably grew up in the village of Westhumble) writing in his book A tour thro' the Whole Island of Great Britain (first published in 1724):

.. the current of the river being much obstructed by the interposition of those hills, called Box Hill ... it forces the waters as it were to find their way through as well as they can; and in order to do this, beginning, I say, where the river comes close to the foot of the precipice of Box-Hill, called the Stomacher, the waters sink insensibly away, and in some places are to be seen (and I have seen them) little channels which go out on the sides of the river, where the water in a stream not so big as would fill a pipe of a quarter of an inch diameter, trills away out of the river, and sinks insensibly into the ground. In this manner it goes away, lessening the stream for above a mile, near two, and these they call the Swallows.

When the Dorking to Leatherhead railway was constructed in 1859, a fossilised swallow hole was discovered in the cutting at the south end of Box Hill and Westhumble railway station, suggesting that even in its early history, the river possessed swallow holes.

Not all of the water removed from the river by the swallow holes, is returned to the channel at Leatherhead. The chalk aquifer also feeds the springs at the southern end of Fetcham Mill Pond, which have never been known to run dry. A survey carried out in March 1883, estimated that the Fetcham springs were producing approximately 3.6 million gallons of water every day. [ JW Grover (1887) Chalk springs in the London basin, illustrated by the Newbury, Wokingham, Leatherhead and Rickmansworth Water Works "Proceedings of the Institution of Civil Engineers" 90] A second survey performed in 1948, estimated that the same springs were yielding approximately five million gallons of water a day. [ FH Edmunds (1948) Correspndence on the movement of water in the middle and lower chalk of the River Dour catchment "Journal of the Institution of Civil Engineers" 29 73]

Literature

In "The Faerie Queene" (first published in 1590) Edmund Spenser wrote of the river:

And Mole, that like a nousling mole doth make
His way still under ground till Thamis he overtake. [The Fairie Queen, book 4, canto 11, verse 32]

It has been proposed [ [http://www.zenigmas.fsnet.co.uk/phoenix.htm William Pierce was Shakespeare, Bacon, Marlowe - and just about everybody else! ] ] that the following lines from Spenser's poem "Colin Clouts come home againe" (published in 1595) also refer to the river:

Old father "Mole", ("Mole" hight that mountain gray
That walls the Northside of "Armulla" dale)
He had a daughter fresh as floure of May,
Which gave that name unto that pleasant vale;
"Mulla" the daughter of old "Mole", so hight
The Nimph, which of that water course has charge,
That springing out of "Mole", doth run it downe right
To "Butteuant".... [Colin Clouts come home again lines 104-111]

In "Poly-Olbion" (first published 1619) the poet Michael Drayton described the journey taken by the River Thames to the sea:

As still his goodly traine yet every houre increast,
And from the "Surrian" shores cleer "Wey" came down to meet
His Greatnes, whom the "Tames" so gratiously doth greet
That with the Fearne-crown'd Flood he Minion-like doth play:
Yet is not this the Brook, entiseth him to stay.
But as they thus, in pompe, came sporting on the shole,
Gainst "Hampton-Court" he meets the soft and gentle "Mole".
Whose eyes so pierc't his breast, that seeming to foreslowe
The way which he so long intended was to go,
With trifling up and down, he wandreth here and there;
And that he in her sight, transparent might appeare,
Applyes himselfe to Fords, and setteth his delight,
On that which might make him gratious in her sight.. [Poly-Olbion, Song XVII lines 20-32]

But "Tames" would hardly on: oft turning back to show,
For his much loved "Mole" how loth he was to go.
The mother of the "Mole", old "Holmsdale", likewise beares
Th'affection of her childe, as ill as they do theirs:
But "Mole" respects her words, as vaine and idle dreames,
Compar'd with that high joy, to be belov'd of "Tames:"
And head-long holds her course, his company to win.
"Mole" digs her selfe a path, by working day and night
(According to her name, to shew her nature right)
And underneath the Earth, for three miles space doth creep:
Till gotten out of sight, quite from her mothers keep,
Her foreintended course the wanton Nymph doth run;
As longing to imbrace old "Tame" and "Isis" son... [Poly-Olbion, Song XVII lines 47-50, 53-57, 59-64]

He writes in the appendix to Song XVII

This "Mole" runnes into the earth, about a mile from "Darking" in "Surrey", and after some two miles sees the light againe, which to be certaine hath been affirmed by Inhabitants thereabout reporting triall made of it.

John Milton (1562?-1647) described the river as

sullen Mole that runneth underneath

In a similar vein, Alexander Pope (1688-1744) wrote in his poem "Windsor Forest" (first published 1713)

And sullen Mole that hides his diving flood

Robert Bloomfield (1766-1823) writes the following lines about the Mole Valley in his 1806 poem "Wild Flowers".

Sweet Health, I seek thee! Hither bring
Thy balm that softens human ills;
Come on the long drawn clouds that fling
Their shadows o'er the Surry-Hills.
Yon green-topt hills, and far away
Where late as now I freedom stole,
And spent one dear delicious day
On thy wild banks romantic Mole.

Ay there's the scene! Beyond the sweep
Of London's congregated cloud,
The dark-brow'd wood, the headlong steep,
And valley paths without a crowd!
Here Thames I watch thy flowing tides,
Thy thousand sails am proud to see;
But where the Mole all silent glides
Dwells Peace - and Peace is wealth to me. [ R Bloomfield (1806) "Wild Flowers; or Pastoral and Local Poetry"]

Extract from "The River Mole or Emlyn Stream" by Mary Uniacke (writing under her maiden name Mary Drinkwater-Bethune), which was published in 1839.

Who may count back that forgotten time
When first the waters forced an outlet here:
When the foundations of these stedfast hills
Were shaken, and the long imprisoned stream
Flowed through the yawning chasm? That awful day
Yet leaves its trace. The waters find their way,
Now laughing in the sun - now swallowed up
In caverns pervious to their course alone,
They leave their channel dry, and hide awhile
Their silent flow; like bitter tears, unshed
From the dim eye, before a careless world
Unheeding of our grief; but swelling still
In the full heart, which leaves unsoothed, unseen,
And broods o'er ruined hopes, and days gone by.

Crossings of the River Mole

The North Downs Way crosses the river at Box Hill via seventeen hexagonal stepping stones, which are frequently submerged after heavy rainfall. The location is popular both with anglers and families, although swimming is strongly discouraged as the water is polluted in places. The stones give their name to the pub in the nearby village of Westhumble.
When the Burford Bridge was rebuilt in 1937, excavations revealed a "flint-surfaced approach to [a] ford at low level having all the signs of Roman workmanship" suggesting that Stane Street (which ran from London to Chichester via Dorking) crossed the river at this point. [The Times 25th March 1937] In Defoe's time, there was a footbridge at this point, but carts and waggons had to cross the river by a ford.
There are three listed bridges in Leatherhead of which the 14 arch Shell Bridge, built in 1784 is the oldest. It links two small islands in the center of the river with each bank.

Watermills

Domesday Book listed twenty mills on the River Mole in 1086. Five of these were in the borough of Elmbridge. [ [http://www.moleseyhistory.co.uk/books/surrey/industrialHistory/index.html A Guide To The Industrial Archaeology Of The Borough Of Elmbridge] ]

Downside Mill, Cobham was the mill of the manor of Downe. It has been used for many purposes including the processing of corn, paper, iron, tinplate and flock and the generation of electricity. The present building dates from the 18th century but it is inaccessible to the public.

Cobham Mill, downstream of Leatherhead, consisted of two mills used for grinding corn. In 1953 the larger mill was demolished by Surrey County Council to allieviate traffic congestion on Mill Road. The remaining red brick mill dates from the 1822 and was in use until 1928. It was restored to full working order by the Cobham Mill Preservation Trust, and is now open to the public from 2pm to 5pm on the second Sunday of each month (between April and October).

Esher Mill was at the end of Lower Green Road where there is now an industrial estate. It was used to process corn, brass wire, iron, paper, linoleum, and books. For many years there may have been two mills on the site for corn grinding and industrial use. There were a series of fires over a century and after the last in 1978 the buildings were demolished.

East Molesey Upper Mill was associated with the manor of Molesey Matham. It was used to produce gunpowder from the time of the Commonwealth until about 1780. The island where it stood now forms part of the ornamental gardens of a housing development called "The Wilderness".

East Molesey Lower Mill, also known as Sterte Mill, was associated with the manor of Molesey Prior. During the Commonwealth it was used for gunpowder manufacture, but after the restoration of the monarchy in 1660 it reverted to corn milling. An old timber structure was replaced by a brick building in the 1820's which can be seen from the bridge over the Ember in Hampton Court Way.

In addition there was Ember Mill, which stood on the banks of the old course of the River Ember near Hampton Court Way.

Hydroelectric power

In 2004, two 27.5 kW low-head hydro turbines were installed in an existing 18th century weir near Betchworth in Surrey, to generate electricity. Approximately 90% of the energy generated is fed into the regional electricity grid, while the remainder is used to supply the Betchworth Park Estate, where the weir is situated. [ [http://www.tvenergy.org/pdfs/betchworth-estate.pdf Small Hydroelectric Power Station, Betchworth Park, Surrey] ]

The River at Gatwick Airport

The course of the river at Gatwick has been considerably altered since the airport opened in 1932 and it now flows under the main runway in a culvert. A 1.9 km section of river north of the runway and the west of the North Terminal was diverted in 1999 at a cost of £1.2M, to allow for airport expansion. Meanders were introduced into the course of the river and flood defences were improved. The impact on the river biodiversity has been positive and water draining from the airport surfaces is now held in a series of balancing ponds before being released into the river.

In 2003, Gatwick Airport Ltd pleaded guilty to charges of allowing chemical pollution to enter the River Mole after a detergent, used to clean rubber and oil from the runway, was washed into Crawters Brook by airport workers. [ [http://news.bbc.co.uk/1/hi/england/southern_counties/3237285.stm BBC NEWS | England | Southern Counties | Airport guilty of killing fish ] ] The Environment Agency estimated that up to 5200 fish of 14 different species were killed as the pollution spread downstream. The airport was fined £30,000 by Lewes Crown Court. [ [http://news.bbc.co.uk/1/hi/england/southern_counties/3456215.stm BBC NEWS | England | Southern Counties | Airport fined for killing fish ] ]

River Ember Flood Relief Channel and Confluence with the Thames

The River Mole originally flowed into the River Thames at the point where the present Hampton Court bridge now crosses the Thames (approximately 500 m upstream of the present confluence, on the reach above Teddington Lock).

However, during the early 1930s, when Hampton Court Way and the bridge were built, the River Mole was redirected to flow into the River Ember and both rivers now enter the Thames in a single widened and straightened channel once occupied only by the River Ember. There have been further alterations to the courses of these two rivers in a major flood prevention scheme since serious flooding in the area in 1947 and 1968. [ [http://www.surreyproperty.com/east-molesey-history.html East Molesey history - SurreyProperty.com property and relocation guide ] ]

Photograph of the River Ember Flood Relief Channel under construction in 1981. [ [http://www.geograph.org.uk/photo/4412 River Ember Flood Relief Scheme:: OS grid TQ1467 :: Geograph British Isles - photograph every grid square! ] ]

Tributaries

The order is from the source to the mouth:

* Gatwick Stream
* Spencer's Gill
* Burstow Stream
* Salfords Stream
* Redhill Brook
* Earlswood Stream
* Baldhorns Brook
* Leigh Brook
* Wallace Brook
* Stanford Brook
* Holmwood Stream
* Pipp Brook
* The Rye
* Bookham Brook

Distributary

*River Ember

ee also

* List of rivers in England

References

External links

* [http://www.environment-agency.gov.uk/subjects/flood/floodwarning/063WAFS04 Environment agency]
* [http://216.31.193.173/gwcl/Thames/Chalk-Leatherhead/GW_QRepChalkLeatherhead.html Groundwater quality]

River item line X|upstream=Longford River, Water Gallery (north)
downstream=The Rythe (south)
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River Ember