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. c<x)ling water continuation of the Hampshire Wroxall Stream, the ScotcheU’s This breach occurred as a and for agriculture. Basin with low and undulating Brook and a number o f small result of a depression of the All abstractions, whether topography characterised by tributaries before it cuts land, or rise in sea level, which from groundwater or from often heavy soils and many through the central chalk ridge lasted until about 2 . 0 0 0 b c and rivers are subject to licences small streams. On the central at Brading. 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 ARBECUE L/ i £ * Stokes SITE Bay 3 NAT. SAIliNG CENTRE D-OA C O W e S ROYAL YACHT SQUADRON GilkickerSEAt Pt. a h v C o w e s Gurnar«U48«SfiH^, ^ pyp^»r9i l Osborne INGTON W N E6 o > 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 Br<x>k and the o f between 5 and 160 m'/d to the species diversity.