Rivers of the Isleofwight

NRA Southern 34

RIVERS OF THE ISLEOFWIGHT

Sandown Sea Wall

NRA National Rivers Authority Southern Region

Guordians of the Water Environment vertically. As on the mainland intersecting the ridge at Shide. Wootton Creek owe their orig­ there are few streams on the The Lukely Brook which rises ins to this movement. RIVERS OF permeable Chalk. Across the in the Bowcombe Valley joins South o f the Island the Chalk the Medina at the head of the HYDROLOGY used to lie in a manner similar estuary in Newport. The apt Rainfall on the Island varies THE ISLE to the Hampshire Downs but name of the river derives from from about 840 mm (3 3 ") on here the rivers over time have the symmetry with which it the coast to about 736 mm cut through the Chalk and divides the Island into the two (2 9 ") inland. The Isle of Wight OF WIGHT exposed the older Greensands Hundreds or Liberties of East has suffered frequent water and ultimately on the South and West Medina. supply problems due to its East and South Western coasts, limited surface sources and the Wealden Clays. The Chalk high summer population. The HISTORY AND cap o f St Catherine’s Down and Island is, however, well pro­ St Boniface Down is now all vided with underground water GEOLOGY that remains of a once more and following several years of The shape o f the Isle o f Wight extensive Chalk downland. short supply and hosepipe resembles a diamond, measur­ This area with its generally light bans in the early Seventies, ing 23.5 miles from East to West sandy soils is again drained by several new sources have been and 13.75 miles North to South. a multitude of small streams developed. The Cross Solent Even though its area is only 381 and rivers which are often Main was also laid between sq km (155 square miles), there spring fed from either the Fawley and Gurnard to import is contrasting landscape as a Chalk or Greensands. water from the lower reaches result o f the varied geology'. Where the Clays and Sands of the River Test. In addition to In fact the geology o f the are exposed to the action of the this almost all properties on Island is almost a microcosm o f sea on the South and East coast the Isle of Wight have indi­ that o f the whole o f South East there are extensive areas of vidual water supply meters England in a very small area. landslips. A subsidiary’ cause of which were fitted in the late There are three distinct form­ this land slipping is ground­ 1980’s. These meters have Newtown Creek, Upper Reaches ations, the Tertiary Clays and water moving through the resulted in a decrease in water Sands in the North o f the Island relatively soft rocks. Some of The Western Yar was once a supply demand on the island which are similar to those in the best examples o f this can river with a well developed which has also helped to the Southampton area of the be seen around the Blackgang system of tributaries but its balance the shortfall in water Hampshire Basin, the central Chine and Brook areas where upper catchment has been resources. Chalk ridge which used to con­ the coast is moving back at a destroyed by erosion of the The porous chalk around nect via the Needles to the relatively rapid rate. Where in Channel coast. Protection Carisbr(H)ke is a long standing Chalk o f the Isle o f Purbeck, Victorian times it was possible works now prevent the sea source of underground water and the Greensands, Gault and to walk to the sea down Black­ running into the Western Yar at which is particularly close to Wealden Clays in the South of gang Chine there is now a cliff Freshwater Gate though the the surface and requires min­ the Island which equate with up to 100 m high and fields, freshwater spring which is its imal treatment for potable the Weald o f Kent and Sussex. roads and properties are being source ebbs and flows coincid- supply. Southern Water Services lost to the sea. ently with the tide. The river Ltd pumps the water from bore­ Except for a few short brooks must once have been one of the holes in the Bowcombe valley on the South coast and the steep largest on the Island but is now and at Carisbrooke to supply rivulets which have created no more than a brook with a dis­ the local community. the chines of the Southern Cliffs, proportionately large estuary. Another source of ground­ all the Island streams flow Until well after the last Ice water is the Lower Green- northwards. These include the Age the Isle o f Wight was part sand. Western Yar, the Newtown of the mainland. A major trunk Water is taken from three River (Caul Bourne) to the stream, the Solent River, flowed boreholes in the Medina West, and the Palmer’s, Black- eastwards from the River Frome catchment and transferred via bridge and Monktonmead in Dorset along the line o f the a pumping station at Brooks to the East. Altogether Solent and Spithead, to outfall Blackwater to the nearby there are no fewer than fifty- to the sea in the Littlehampton Eastern Yar at Kennedy. Three separate catchments having area. Its northern tributaries other boreholes in the Yar outfalls into tidal waters. would have included the Avon. catchment are also used to The two largest rivers, the Test and Itchen and its southern discharge directly to the Medina and the Eastern Yar tributaries w'ould have been headwaters of the Eastern Yar Eastern Yar both rise as springs from St the streams which drained from for subsequent abstraction at All these rocks were laid Catherine's Down which is a the northern slopes of Purbeck Sandown. down in a series o f subsiding feature of the southern chalk and the Isle of Wight. The In addition to abstractions for sea basins mainly in the Cret­ outcrop. The Eastern Yar is drainage system was dismem­ public water supply there are a aceous and Tertiary geological 27 km long w'ith a catchment bered by the sea breaking into number of small abstractions timescales. The Northern part o f 76 sq km. The river flows the main channel between Pur­ from groundwaters and rivers o f the Island simply forms a North-East collecting the beck and the Island. for sand washing. cBrading. also led to the submergence of issued by the National Rivers ridge the Chalk rock has been The River Medina is 17 km the downstream reaches of the Authority, which imposes con­ bent up in a geological structure long with a catchment area of North flowing rivers, giving ditions to ensure that water is known as a monocline so that 71 sq km. The river flows due them their well marked estu­ taken at the right times and only the rock on the Northern edge North, collecting the Merstone aries. The Harbours o f Yar­ from the places where it can o f the ridge is lying almost Stream at Blackwater before mouth, Newtown, Cowes and most be spared. OLENT MARITIME ESCUE CENTRE Lee- OUNTRYPARK Won-the-Solent w

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Seaview

Netti Sandown Sea Wall

Totland Bayj Coloured Sands Chine & Chairlift Aium Soyj Needlei

NEEDLES OLD BATTERY(NT)

Cartography prepared and published by ESTATE PUBLICATIONS with the editorial assistance of the SOUTHERN TOURIST BOARD National Rivers Authority Based upon the O R O N A N C E S U R V E Y maps with the sanction of the controller of H M Stationery Office NNOSE Southern Region OF SMUGGLING Estate Publications j Crow n copyright reserved HISTORY

ST. CATHERINE’S POINT wrenceentnor BOTANIC GDN The NRA manages water these works are in the range of with dace becoming the pre­ coast protection works are the resources by measuring river 300 and 900 m'/d. There is a dominant species below responsibility o f South Wight levels and flows using gauging smaller, but significant input of Heasley Manor. Between New- Borough Council. weirs and water level recorders. treated sewage effluent to the church and Alverstonc small These defences prevent the On the Eastern Yar there are headwaters o f the Medina at numbers o f roach are found sea breaking into the river recorders at Sandown and Chale ( 160 m'/d). A number of amongst the dace and below system, protecting 3(H) hectares Budbridge as well as recorders minor sewage works with flows Alverstone carp and rudd add of farmland and about a hun­ on the Scotchell’s Brk and the o f between 5 and 160 m'/d to the species diversity. In the dred properties on the Brading Wroxhall Stream. In the Medina serve other small communities slow flowing waters between and Sandown levels. The wall catchment there are recorders on the Island. Altogether only Yarbridge and St Helens there was strengthened in 1978 and on the main river at Blackwater 6.5% o f the Island’s sewage is are good stocks o f dace, roach, the associated timber groynes and Upper Shide, and on the discharged to the freshwater carp and bream together with were repaired. The Authority Merstone Stream and the Lukely sections o f rivers and streams. small numbers o f rudd, perch is also responsible for sea and Brestuaries. Yarmouth, Newtown, Gurnard, groundwater monitoring bore­ the remaining few properties The Hastern Yar between Ryde and the tidal walls adja­ holes on the Island. connected to old outfalls will Horringford and its mouth, and cent to the sluices through be re-directed into the new the Medina between Chillerton which the Eastern Yar enters WATER QUALITY sewerage system during 1992. and Newport are designated as the Harbour. River water quality is largely There are very few industrial Cyprinid fisheries under the There are 114 km (71 miles) determined by the underlying discharges and most water EEC Freshwater Fisheries Direc­ of main river on the Island for geology, land use and urban quality problems result from tive. This reinforces the water which the Authority has flood development. Most water qual­ surface water which has been quality standards to which the defence responsibility. The ity problems occur on the clay contaminated with oil before rivers must be protected. river systems of the Island are soils o f the northern half of the being discharged from drains. typically small hill streams Island, especially where there In particular the Scotchell’s rising at the base o f the chalk are problems with domestic Brook at Sandown receives sig­ Brown Trout beneath the Downs, periods of septic tanks. Most livestock nificant diffuse pollution as a high flow are therefore short­ farming is carried out on these result o f run-off from urban lived but peak flows are high. less w ell drained soils and this areas. In rural areas there are Consequently the lower is reflected by the number o f occasional pollutions from reaches of the rivers, particular­ agricultural pollutions occur­ septic tanks or from farm slurry’ ly the Eastern Yar and Thorley ring in these areas. and silage. Brook, are subject to fairly fre­ However, the high level o f The natural quality' o f the quent flooding adjacent to the public interest in environmental streams is variable. Those aris­ main channel, especially when issues on the Island results in ing from springs in the chalk their discharge to the sea is many pollutions being reported are well buffered and neutral, tide-locked. promptly to the Authority, whereas those originating from Following fltxxling o f proper­ allowing early action to be the iron rich sandstones may ties in the Schlgreen area of taken. be acidic, depositing rusty Freshwater in August 1954 a The National Rivers Authority deposits on vegetation and flixxl alleviation scheme was sets quality objectives for each gravel. A particularly marked carried out on the Western Yar. stretch of inland and tidal water contrast can be seen between Severe fkxxiing occurred on and imposes conditions on the River Medina and the Mer­ the River Medina on October permitted discharges to ensure stone stream where they meet 1, 1960 when rainfall of that the environmental objec­ at Blackwater. The bed of the 50—60 mm fell following a wet tives are met. Merstone Stream draining from summer and autumn. River On the Isle o f Wight 51.5 km the Ferruginous Sands of St fkxxling was aggravated by

of river have an objective of George’s Down is vividly Mullet tidal factors which limited the Class IB (suitable for high class stained by the iron deposits. discharge o f fkxxlwater to the game and coarse fisheries), and estuary. The valley fkxxled from 36 km of river have an objective FISHERIES Newport to Blackwater with the o f Class 2 ( suitable for reason­ The small size o f the rivers on stretch below Carisbrke ably good coarse fisheries). the Isle o f Wight limits their being particularly badly affec­ None o f the Island’s rivers have potential as fisheries though FLOOD DEFENCE ted. A second fkxxling incident objectives o f Class 3 or ('.lass 4. the lower reaches of the Eastern The National Rivers Authority followed at the end of January Most o f the population is con­ Yar at Brading and Alverstone is responsible for protecting when rainfall o f 60—70 mm centrated along the coast and are fished for coarse fish. The people and property from flood­ prtxluced fkxxis in Newport the resulting domestic effluents steeper, smaller streams which ing by rivers and from the sea. which were only slightly less are discharged to the sea. There comprise the headwaters of the The Isle o f Wight, although severe. is only one major inland sewage Medina and Yar are character­ exposed to the full force of In response to these incid­ treatment works on the Island, ised by small wild brown trout, storms and gales in the English ents a comprehensive fkxxl which serves Newport and was stoneloaches, bullheads and Channel, is well endowed with relief scheme for 4 km of the commissioned in 1986. This eels. On the Medina these natural defences, namely its River Medina and another for discharges to the tidal River species are typical along the high coastline and cliffs. the Lukely Brcx>k between Medina at Fairlee and has a whole length o f the river with There are 4.65 km o f sea Towngate Bridge and Westmin­ consented dry weather flow of a few fairly sizeable trout be­ defences which protect land ster Mill were installed by the 12,115 m'/d. There are small tween Blackwater and Newport. below sea level, the most sig­ Isle of Wight River Authority. sewage works at Roud. Brading Sea trout are infrequent visitors nificant being Sandown Sea These schemes improved and St Helens discharging to to the Medina Estuary and the Wall which has a 600 year his­ retaining walls, removed con­ the catchment of the River Yar freshwater reaches below Shide. tory. The NRA is responsible for strictions, re-aligned the chan­ as well as two relatively new On the Eastern Yar. coarse 550 metres of the frontage nel and provided seven sewage works at Wroxall and fish such as carp are first found between Fort Street and the velocity-control weirs. (iodshill. Drv weather flows at downstream of Horringford Grand Hotel whiLst the adjacent Other schemes to alleviate Hooding in the 19S0s were car­ Biography of an Island. REFERENCES Gollancz. ried out on the Shalfleet Mill All press, M. Exploring the Stream, Thorley Brook and on Medina Islander Magazine. White, H.J.O. (1921). A short account of the Geology of the 20 km o f the Eastern Yar be­ Cowes Library. Isle of Wight. Institute of tween St Helens and Southford Hyland. P. (1984). "Wight”, Geological Sciences. Mill. At Monktonmead Brook two electrically operated pumps at KEY the sea outfall supplement gravity drainage o f water A Sea Outfalls through tidal flaps when high rainfall and adverse tides (S) Sewage Treatment Works <300m3/d coincide. O S e w a g e Treatment W o rks > 300m3/d The NRA Flood Defence Department ensures that rivers Public Water Supply-Surface are kept free from obstructions Cowes by maintaining channels and Public Water Supply-Ground cutting weed throughout the year. It also ensures that tidal sluices are maintained in good condition. CONSERVATION The rivers of the Isle o f Wight are small compared with those on the mainland and many have

been modified by river engin­ Toth eering, but they support, in patches, a diverse aquatic flora. The more common species include Fool's water-cress, water mint and yellow flag as well as less common species like marsh mallow. The river systems and asso­ ciated wetlands including reed beds, marshy grassland and carr Dunnose w(xxlland provide important habitats for wildlife. Some are Ventnor of national importance and have been designated as Sites of St Catherine's Point Special Scientific Interest. Fresh­ water Marshes, a Local Nature 0 9 9 9 1 0 Reserve is such a site, where the NRA has been directly Sections showing the general relations of the rocks along the lines Y—Y' drawn on the map involved in management to maintain the interest o f the site. Ventnor Ryde Port sea Ports Down Chichester Petersfield I Spithead Island Anticline Syncline National Riv- \uthor. Information ,rre Heed ( Conjectural base of recent deposits

C lass N o ...... Vertical Stale about ten times the Horizontal

NRA National Rivers Authority Southern Region Regional Office Guildboume House Chatsworth Road Worthing West Sussex BN11 1LD NRA (Southern) Boundary CHALK (with some (0903)820692 July 1992 Upper Green sand)

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