94-631: Norbury Brook is a tributary of the River Wandle that rises near Lower Addiscombe Road and flows north-west through Selhurst , Thornton Heath , and Norbury before joining the Wandle at south Wimbledon . A short stretch of this is visible in Selhurst at Heavers' Meadow, near Selhurst railway station , where the brook can be seen in a concrete channel next to the British Rail works as it runs north west along
188-408: A Local Nature Reserve . The Mole Gap forms part of a Special Area of Conservation and is an SSSI of European importance. 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, most recently in 2022. In John Speed 's 1611 map of Surrey, this stretch of the river is denoted by
282-576: A Special Area of Conservation and is an SSSI of European importance. The stretch of river between Thorncroft Manor (1 km [0.6 mi] south of Leatherhead ) and River Lane in Fetcham has been designated a Local 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
376-571: A Grand Imperial Ship Canal from Deptford to Chichester passing through the Mole Gap, however he was unable to attract sufficient financial interest in his scheme. Today the Mole is navigable for the 400 m (440 yd) from the confluence with the River Thames to Molember Weir at East Molesey where there is a private mooring facility. The river may be paddled all year by canoe between Brockham and Fetcham with an appropriate licence from
470-537: 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
564-498: A diverse fish population, including chub, dace, roach, bleak , large pike and barbel. At the confluence of the Mole and the River Thames at Hampton Court Palace it is possible to catch a wide variety of coarse fish species. 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
658-643: A flat-bottomed dug-out canoe were found at the confluence of the Mole and Thames in 1877 by a local boatman. The canoe is preserved at the Pitt Rivers Museum in Oxford . The Mole Gap and North Downs do not appear to have been settled until the late Stone Age: A large axe, typical of a "rough-out" axe produced during the Neolithic period, which was discovered in 1952 during building work in Westhumble, A flint mine of
752-627: A gravel spawning area to encourage chub and dace in addition to roach . In 1974 zander , a non-indigenous coarse fish native to Europe, were introduced legally to Old Bury Hill Lake which supplies the Pipp Brook. Zander have been caught in the Lower Mole below Dorking since the 1980s. In the Mole Gap between Dorking and Leatherhead the river supports populations of chub, dace, barbel , and brown trout. Both barbel and brown trout are extremely sensitive to water quality and pollution. Below Leatherhead
846-416: A lower flood plain, which broadens as the river turns in an axehead meander. At the east end of Painshill Park, the flood plain narrows into a trench about 60 m (66 yd) wide, in which the river runs northwards for 6.5 km (4.0 mi) towards Hersham, where the river enters the flood plain of the River Thames. Between Cobham and Esher, the Mole's historic courses have deposited gravel on top of
940-410: 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
1034-594: 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 (1.2 mi) apart at their closest point near Painshill Park. During the Middle Pleistocene period, 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
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#17328516922131128-621: A river in England is a stub . You can help Misplaced Pages by expanding it . River Wandle The River Wandle is a right-bank tributary of the River Thames in south London , England. With a total length of about 9 miles (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 –
1222-446: A series of hills accompanied by the legend "The river runneth under". However the river's name is unlikely to have derived 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). Domesday Book lists twenty mills on the river in 1086, of which Sidlow Mill
1316-537: A small lake at Baldhorns Park, before running eastwards through a largely rural area towards Crawley. The first tributaries to join the young river drain the northernmost part of St Leonard's Forest , between Horsham and Crawley, although much of the forest is in the catchment area of the River Arun . The Mole skirts the northern suburbs of Crawley where it is joined by its first major tributary, Ifield Brook, which drains Ifield Mill Pond . The first gauging station on
1410-467: A smaller 50-metre (160 ft) cliff at Ham Bank in Norbury Park . The sudden change from impermeable Weald Clay to permeable chalk and the increased gradient of the river, allow the water table to drop below the bed of the river. Water is therefore able to flow out of the river through swallow holes in the bed and banks, decreasing the volume of water carried in the main channel. The course of
1504-459: A survey in 1958, the geologist C. C. Fagg identified 25 active swallow holes between Dorking and Mickleham ; the majority were only a few centimetres in diameter and were located in the vertical banks of the river below the water line. Most holes were difficult to observe in times of normal or heavy flow and were susceptible to silting up as new holes were continually being formed. A few much larger swallow holes were also observed separated from
1598-492: Is a "charming Surrey steam" and "If Lord Lytton went to fish in the River Mole – and there are still angling clubs there – he would find that he would still be able to catch a trout ". Highly polluting discharges have become less common but have taken place since 2000. 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
1692-524: Is also found along the river, and the downy emerald ( Cordulia aenea ) is found between Box Hill and Leatherhead. The Mole is one of only three locations in England where the river shingle beetle ( Meotica anglica ) is found. A nationally scarce species which is locally common on the River Mole is the greater dodder ( Cuscuta europaea ), a parasitic plant . The Mole catchment area includes twelve Sites of Special Scientific Interest (SSSIs) that include wetland habitats, The Mole Gap forms part of
1786-758: Is first recorded in the Red Book of Thorney in AD 983 as Emen and in the AD 1005 Cartulary of the Abbey of Eynsham as both Emen and Æmen . Variations in the name are recorded throughout the Middle Ages and the river appears as Amele in the Domesday Book of 1086, and subsequently as Emele in 12th- and 13th-century Court Rolls. This name is probably derived from the Old English word æmen meaning misty or causing mists , and
1880-565: Is measured at a fourth gauging station, located at Castle Mill (39 m [128 ft] above OD). At Pixham the Mole meets the Pipp Brook , a tributary draining the northeastern slopes of Leith Hill. Between Dorking and Leatherhead the Mole cuts a steep-sided valley (the Mole Gap) though the North Downs , carving a 170-metre-high (560 ft) river cliff on the western flank of Box Hill and
1974-529: Is one of the few rivers remaining overground in the area. As the boundary between the London County Council and Croydon for many years people wishing to travel south had to get off an LCC tram, walk across the bridge and catch a Croydon tram. West of the bridge the brook becomes the River Graveney, where it flows on to join the Wandle, and ultimately the River Thames . There is a small tributary of
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#17328516922132068-452: 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 ( Old English : Wendelesorde meaning Wendle's Enclosure). In the pleistocene before the carving of
2162-570: 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
2256-620: Is rated good or fail. In the 1980s Wandle was designated as one of the London bus districts. Its logo was a water wheel above the London Transport roundel . 51°27′34″N 0°11′37″W / 51.45938°N 0.19357°W / 51.45938; -0.19357 River Mole#Mole Gap The River Mole is a tributary of the River Thames in southern England . It rises in West Sussex near Gatwick Airport and flows north-west through Surrey for 80 km (50 miles) to
2350-686: Is used. In common with much of the rest of the Weald, the earliest evidence of human settlement along the Upper Mole is from the Mesolithic Period (20,000–7000 BC). Mesolithic sites at Wonham, Flanchford and Sidlow. Finds at Wonham include arrowheads and a plano-convex knife. The Lower Mole appears to have been settled during the same period and a flint axe dating from Mesolithic period found on spit of land close to River Mole in Cobham in 1965. Remains of
2444-671: The British Canoe Union . During the Second World War several sites along the course of the Mole were fortified for the defence of London against invasion from the south. GHQ Line B ran along the North Downs from Farnham and Guildford, crossing the Mole Gap to the north of Dorking and following the river to Horley. Between Betchworth and Box Hill, the north bank of the River Mole was stabilised and made steeper to prevent wheeled vehicles from crossing. At Boxhill Farm, where access to
2538-525: 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 . The two rivers flow either side of the reservoir, before running side by side in a northeasterly direction, merging 400 m (440 yd) before the confluence with the River Thames, on the reach above Teddington Lock . (For the purposes of
2632-619: 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
2726-482: The Thames at Hampton Court Palace . The river gives its name to the Surrey district of Mole Valley . The Mole crosses the North Downs between Dorking and Leatherhead , where it cuts a steep-sided valley, known as the Mole Gap, through the chalk. Much of the catchment area lies on impermeable rock (including Weald Clay and London Clay ), meaning that the river level responds rapidly to heavy rainfall. During
2820-467: The Wey Gap is significantly higher than might be expected from natural rainwater percolation alone. It has been suggested that a proportion of the excess water originates from the Mole Gap. At Leatherhead the river leaves the chalk bedrock, moving onto London Clay . The river meanders across an alluvial plain between 400 and 800 m (440–870 yd) wide towards Cobham, where it begins to descend to
2914-585: The Anglian ice sheet caused the Thames to divert southwards and flood the valley of the Mole–Wey river, thus adopting its present route through London . Standard water quality of Mole and its tributaries has improved markedly since the 1990s. In 1990 the Environment Agency assessed 23% of the watercourses as Grade B (good) or better. In 2002 this figure was 60%. Investment in the Sewage Treatment Works in
Norbury Brook - Misplaced Pages Continue
3008-676: 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
3102-458: The Earlswood Brook. From Sidlow, the Mole turns northwest towards Brockham . A number of minor tributaries join the river from the west and are typically second order streams draining the woodland and arable land between Horsham and Dorking. The 18th-century weir at Betchworth was modified in 2004 to facilitate the installation of two 27.5 kW low-head hydro turbines . About 90% of
3196-531: The Graveney called the Little Graveney Stream, which runs through Figges Marsh and was culverted in the early 20th century and is no longer visible. It joins the Graveney near Tooting Junction Station. Two other tributaries of the Graveney are commemorated by local street names, Donnybrook and Fallsbrook Roads. During 1976 drought, water flooded out of sewer on Aberfoyle Road. A house on Edgington Road near
3290-487: The London Clay. The depth of the deposits generally varies from 2.5 to 7 m (8–23 ft); the lower layers are generally highly compacted and cemented together with brick-red iron oxide, whereas the upper layers are loosely packed with angular flints and sand. Remains of a further gravel terrace, containing cherts and flints to a depth of 4 m (13 ft), line the east side of St George's Hill . The river
3384-778: 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
3478-586: The Mole catchment is located on the Gatwick Stream 3 km (1.9 mi) upstream of the confluence with the Mole: Crawley STW discharges 15,000 m (530,000 cu ft) of water per day, and in prolonged dry periods it accounts for up to 75% of the flow of the Mole downstream of the confluence. The mean flow measured at Horley gauging station (52 m [171 ft] above OD) is 1.40 m /s (49 cu ft/s). The Mole passes Horley to
3572-417: The Mole is south of Gatwick Airport (57 m [187 ft] above OD ). The mean flow is 0.33 m /s (12 cu ft/s) and the river ran dry at this point for the first time in the summer of 1995. The Mole runs under the airport runway in a culvert completed in 1985. The course of the Mole within the airport perimeter has been altered several times since commercial flights began in 1945; however
3666-412: The Mole leaves the chalk and turns northwestwards to flow across impermeable London Clay , winding 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. The next major tributary, The Rye , (which drains Ashtead ) joins to
3760-457: The Mole was used for navigation in the past: In the late 13th century, Thorncroft Manor (south of Leatherhead) purchased a shout , a type of boat up to 16 metres (52 ft) in length used to carry produce to market and it has been suggested that stone cut from quarries in Reigate was transported to London via the river. During the 17th century, two bills came before parliament to make sections of
3854-410: The River Mole in 2019: 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. A second non-native species, the edible frog ( Pelophylax kl. esculentus )
Norbury Brook - Misplaced Pages Continue
3948-550: 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. Two such streams, culverted, combine in Central Croydon beneath Bourne Street to form
4042-561: 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
4136-519: 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
4230-583: The Wandle which emerges immediately north-west in Wandle Park. The Wandle is piped part-way-through neighbouring New South Quarter to flow under Purley Way (formerly Waddon Marsh Lane) and part of its retail park. From its central gathering the flow is westwards (or WSW ) until merging with the Carshalton branch. On its route the early Wandle surfaces to receive springs at a long lake Waddon Ponds beside Mill Lane, Croydon. The Coulsdon Bourne and linked Caterham Bourne south of Croydon town centre ran in wet seasons. They have been culverted since before 1900. When
4324-588: The Wandle, as it flowed through her garden, the " River Nile ", in Nelson's memory. However, as Croydon's population grew and use of the water closet increased, the Old Town streams became little more than open sewers and were filled in or culverted from 1840 after outbreaks of typhoid and cholera . 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
4418-613: The ancient boundary of Croydon and Norwood (once the large woodland in Norbury parish). Its long, culverted mouth with the Wandle is in Tooting Graveney – it meets the Wandle fronting the Haydons Road part of Wimbledon in the Borough of Merton. The river has been well-used since Roman times; in the 17th century Huguenots were attracted by the cloth and textile mills which lined
4512-554: The banks of the river. It was heavily industrialised in the 18th and 19th centuries, during the Industrial Revolution , and was declared one of the most polluted rivers in England. The main industries then were tobacco and textiles. The river was used to power 68 water wheels , of which only a few survive, such as at Merton Abbey Mills for the production of paper, print and tapestries. The Liberty print works (latterly Merton Abbey Mills ) and Merton Board Mills dominated
4606-422: The bed and banks. The amount of water lost from the river is significant and in very hot summers the channel can become dry between Mickleham and Thorncroft Manor; this was recorded most recently in 1949, 1976 and 2022. At Leatherhead , the river leaves the chalk and flows across impermeable London Clay . At this point, the water table rises enough for the water to flow back into the main river channel. In
4700-485: The bottom of the site before disappearing beneath Selhurst Road. It is fenced off here because it can be dangerous, especially after a rain storm, where the water level can rise several feet in a few minutes, as the water rapidly drains from the roads and hard surfaces around and into the surface water drain. The brook reappears in Thornton Heath Recreation Ground, running along the western boundary of
4794-467: The canalisation of a short stretch of the River Mole between Betchworth and Dorking to facilitate the movement of chalk from quarry to market. In 1810 the engineer John Rennie proposed a canal linking the River Medway to Portsmouth which was to have a branch to London following the Mole for much of its length. Between 1825 and 1828 the architect and civil engineer Nicholas Wilcox Cundy proposed
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#17328516922134888-400: The catchment area has improved the quality of the discharges into the river, and modifications to the runway and apron drainage systems at Gatwick Airport mean that surface water is diverted to aerated pollution control lagoons and balancing ponds for treatments, including acid/alkali neutralisation, before release into the river. In 1972 a sub-debate on the future cleanliness of the Mole
4982-526: The cutting at the south end of Box Hill & Westhumble railway station , suggesting that even in its early history, the river had swallow holes. The author Daniel Defoe , who attended school in Dorking and probably grew up in the village of Westhumble , described the swallow holes in the River Mole in his book A tour thro' the Whole Island of Great Britain (first published in 1724): ...the current of
5076-523: 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. The river leaves the Weald Clay at Brockham, passing Betchworth Castle and flowing briefly across greensand and Gault Clay to Pixham , 1 km (0.6 mi) northeast of Dorking . A mean flow of 3.74 m /s (132 cu ft/s)
5170-402: The entry to the Mole Gap. Above Meath Green (near Horley ), the terrace corresponds to the flood plain of the river, however from this point downstream to Brockham, the river cuts a narrow trench no more than 150 m (160 yd) wide. A similar trench is runs up several of the Mole's tributaries, notably along Deanoak Brook which follows a local strike . The presence of the trench protects
5264-919: 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
5358-447: The impermeable Weald Clay . From the source to Dorking , the river drains an area of 340 km (130 sq mi), of which approximately 60% is on Wealden or Atherfield Clay, 20% is on Tunbridge Wells Sand and 20% is on greensand . Brickearth deposits are common in the valley around Betchworth and east of Dorking. The upper Mole catchment is dominated by a single broad terrace, which runs continuously from Tilgate Forest to
5452-414: The land from flooding, rendering it suitable for agriculture . Between Dorking and Leatherhead the Mole cuts a steep-sided valley through the North Downs, creating a 170-metre-high (560 ft) river cliff on the western flank of Box Hill. The bedrock is permeable chalk and the water table lies permanently below the level of the riverbed, allowing water to drain out of the river through swallow holes in
5546-468: 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. The West End Common forms part of the Esher Commons , owned and managed by Elmbridge Borough Council . The River Mole forms
5640-471: The main river by a channel of about a metre. About six of these larger swallow holes were found to the west of the Burford Bridge Hotel , along the course of the A24 Mickleham Bypass during its construction in 1936. Initially the surveyors tried 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
5734-408: The meanders visible on the 1839 tithe map in the 1.5 km (0.93 mi) stretch immediately north of the runway were reinstated in 1999, in a £1.2 million project to facilitate airport expansion. The Mole enters Surrey to the south of Horley, where it meets the Gatwick Stream , a tributary draining Worth Forest to the southeast of Crawley. The second-largest Sewage Treatment Works (STW) in
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#17328516922135828-453: The name of the River Ember probably has its origins in this name. The name Mole does not appear until the 16th century, first occurring as Moule in Harrison's Description of Britain of 1577. The antiquarian William Camden uses the Latinized form Molis in the 1586 edition of Britannia and Michael Drayton is the first to use Mole in his poem Poly-Olbion published in 1613. In John Speed 's 1611 map of Surrey this stretch of
5922-408: The north of Leatherhead, before the river is crossed by the M25 motorway . At Cobham the river swings round in a pronounced axehead meander skirting Painshill Landscape Garden , where a 11-metre (35 ft) diameter waterwheel raises water 5 metres (16 ft) from the river to feed the ornamental lake in the park. From Painshill Park the river flows northeastwards to the Thames, passing to
6016-466: The park in a deep concrete channel. Most of the time the brook is fairly shallow, but during heavy rainfall water quickly drains from the adjacent built up areas and the water level rapidly rises. It then continues behind several private houses in between before reaching Norbury Park where, once again, it is hidden behind a tall fence. The brook continues west, to form the boundary between Norbury and Streatham on London Road at Hermitage Bridge, where it
6110-464: 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
6204-565: The railway experienced flooding in 1976, 1993 and 2000. Besley and Leverson Streets descend to the valley of the Graveney and Fallsbrook Road, possibly following course of stream. Up to the 1970s, a house on Streatham Vale near junction with Farmhouse Road had, in the front garden, a badly eroded Roman pillar (milestone?) with lettering ____ER, FLU___ carved on it. Streatham was known as Streatham Wells in many old maps. 51°25′31″N 0°11′06″W / 51.4252°N 0.1849°W / 51.4252; -0.1849 This article related to
6298-425: The remainder of this article, the River Mole and the River Ember are treated as a single entity.) 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
6392-444: The river navigable . The first, in 1663, was passed by the House of Commons but was defeated in the House of Lords . During the following year (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. The only Surrey river to have been made fully navigable is the combined lower section of the River Wey . In 1798 William Marshall advocated
6486-424: 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
6580-430: The river from the north bank was required for the herd of dairy cows, a row of twelve concrete cylinders were cast as an anti-tank measure. Gun mounts were also installed to protect both Boxhill and Deepdene bridges and several pillboxes were installed. An anti-tank ditch was dug from the Stepping Stones eastwards across the fields belonging to Bradley Farm (now Denbies vineyard ). The river crossing at Sidlow Bridge
6674-411: 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
6768-401: The river is denoted by a series of hills accompanied by the legend "The river runneth under". However the river's name is unlikely to have derived 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). In John Rocque 's 1768 map of Surrey, the name Moulsey River
6862-564: 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 Weald Clay provide an excellent habitat for stoneflies , caddisflies , fast swimming mayflies and riffle beetles . The beautiful demoiselle ( Calopteryx virgo ) disappeared from the River Mole during the 1960s owing to deteriorating water quality, but has since recolonised. The white-legged damselfly ( Platycnemis pennipes )
6956-572: The river through Norbury Park was partially straightened when the Epsom to Horsham railway was built in 1837, with the removal of a small meander north of Westhumble . The meander was reinstated in 1997, in an attempt to enhance this area of the Park, although it has since become blocked by silt . The entirety of the Mole Gap lies within the Surrey Hills Area of Outstanding Natural Beauty . At Leatherhead,
7050-472: 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
7144-518: The runway, was washed into Crawters Brook by airport workers. The Environment Agency estimated that up to 5200 fish of 14 different species were killed as the pollution drained downstream. The airport was fined £30,000 by Lewes Crown Court . In May 2003, sewage leaking from a pump operated by Thames Water leaked into the Stanford Brook, killing coarse fish in the Gatwick stream. Water quality of
7238-477: The same period has been discovered at East Horsley along with Neolithic flakes of flint at Fetcham and Headley Heath . Significant Bronze Age finds include a bronze sword found close to the river north of Amberley Farm near Charlwood and a small hoard of weaponry consisting of two palstave axes and a scabbard chape was discovered in 2003 in Norbury Park close to Ham Bank. It is not clear to what extent
7332-431: The second half of the 20th century, pollution levels in the river were high; however, since 1995 the water quality has improved dramatically and the Mole now boasts the greatest diversity of fish species of any river in England. Twelve Sites of Special Scientific Interest (SSSIs) that include wetland habitats are located within the Mole catchment area , and the stretch of river through Leatherhead has been designated
7426-488: 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. 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
7520-629: The south of Croydon. It ran along Southbridge Road and upon reaching Old Town it reached a maximal 20 ft (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
7614-519: 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. The Environment Agency measures
7708-548: The southwest of Dorking . 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. The Mole rises in Baldhorns Copse 700 m (0.4 mi) to the south of the village of Rusper in West Sussex . It flows initially southwards for 1 km (0.6 mi) to
7802-503: The springs at the southern end of Fetcham Mill Pond, which have never been known to run dry. A survey in March 1883 estimated that the Fetcham springs were producing about 3.6 million imperial gallons (16,000 m ) every day. A second survey in 1948 estimated that the same springs were yielding about 5 million imperial gallons (23,000 m ) a day. The water table in the chalk of
7896-464: The surrounding chalk and provided with a manhole and access shaft to allow periodic inspection. In the late 1960s the domes were reopened and inspected and the alluvium in the largest swallow hole was observed to have subsided by 1.5 metres (4 ft 11 in) under the centre of one of the domes. When the Dorking to Leatherhead railway was constructed in 1859, a fossilised swallow hole was discovered in
7990-447: 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 of invertebrates , angiosperms and fish. Chemical status, which compares the concentrations of various chemicals against known safe concentrations,
8084-581: The water table is medium or high these waters meet at Purley, run in a culvert the length of the Brighton Road, South Croydon, and merge into the surface water drains and culverts in the town centre (which become much of the above stream). The Norbury Brook is in its western section for parochial boundaries called the Graveney River. Aggregated streams combine under Grant Road, Addiscombe. Straightened, it roughly bounds Croydon and Lambeth Boroughs forming
8178-585: The west bank of the Mole, west of the Island Barn Reservoir. The Heath is an area of rough scrubland and, despite its name, is a reclaimed landfill site hence its large but artificial mound and small plateau. The site is a rich habitat for birds including the redshank and little ringed plover . The Mole rises south of Rusper in West Sussex, where an outcrop of the Hastings Beds sandstone dips below
8272-454: The west of Esher Commons and then forming the boundary between Hersham and Esher , where the mean flow of the river is 5.43 m /s (192 cu ft/s). In response to heavy flooding of East Molesey and Thames Ditton in September 1968 , the river was modified downstream of Albany Bridge to the Thames and new flood defences were constructed. Finally the Mole splits into two branches at
8366-499: The west, flowing north towards Sidlow and entering a largely rural area. 0.7 km (0.4 mi) south of Sidlow the mean flow is measured as 2.21 m /s (78 cu ft/s) at Kinnersley Manor gauging station (48 m [157 ft] above OD). The Earlswood Brook, a tributary draining the urban area of Reigate and Redhill , joins the Mole at Sidlow. The largest STW in the Mole catchment (Reigate STW) discharges up to 118,500 m (4,180,000 cu ft) per day into
8460-458: 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 ). Molesey Heath Local Nature Reserve lies on
8554-578: Was had by the House of Lords , involving a member of the South-East Strategic Committee of the Thames Conservancy (succeeded by the Environment Agency ) and four others. In this it was said, "...I can see no future for [The Mole]. The Mole Valley has been polluted. The Mole where I used to tickle trout in my youth is a drain, and it will remain a drain." Rebuttals included that the Mole
8648-457: Was heavily defended and a line of pill boxes was constructed on the north bank of the river. Concrete anti-tank dragon's teeth were built on both sides of the river, a short distance upstream of the bridge, as an obstacle to armoured vehicles . The North Downs Way crosses the river at Box Hill via seventeen hexagonal stepping stones , which are frequently submerged after heavy rainfall. The current stones were dedicated in September 1946 by
8742-413: Was introduced to a site at Newdigate in the early 1900s. It has in 2008 been recorded in tributaries of the River Mole at Capel and Brockham . The River Mole has the most diverse fish population of any river in England. The Gatwick Stream is dominated by coarse fish such as brown trout , brook lamprey , and eel . In 2003, the upper River Mole near Meath Green Lane, Horley, was enhanced to create
8836-465: Was the oldest, dating from Saxon times . The drainage area of the Mole is 477 km (184 sq mi) and forms 5% of the River Thames 's catchment area above Teddington . The catchment area receives 761 mm (30.0 in) of rain each year; the greatest average level of rainfall is 800 mm (31.5 in) around Crawley . The Mole catchment reaches a maximum elevation of 265 m (869 ft) above Ordnance Datum at Leith Hill to
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