■ NRA Southern 31

THE CUCKMERE RIVER

NRA

National Rivers Authority

Southern Region Guardians of the Water Environment THE CUCKMERE RIVER COURSE ITie many rivulets which form the headwaters of the Cuckmere River rise 20 miles from the coast in the Heathfield ridgeway. From this southern ridge of the high Weald, some 130 metres above sea level, streamlets combine to form the major headstreams. The true source of the Cuckmere rises in the north of Heathfield Park, just below the ridge road. It feeds the lakes of the park and then flows south. 'Phe name Cuckmere is a Saxon word meaning “fast flowing water” perhaps reflecting that in its 7 kilometres, the river falls 100 metres. It collects first the Flitterbrook from the east and next the Waldron Gill from Horam and Vines Cross to the west. The river then hooks westward, towards its " ' T T 1! -^vci uic n u u ic s, longshore drift ( the tendency for shingle to be driven from west to east by the prevailing south west winds ) had forced the mouth of the river eastwards. The shingle bar formed by the drift forced the river against the first of the Seven Sisters until it blocked the mouth. The river was then obliged to break through at a new point and spit formation began again. In 1946, man intervened. A straight cut was made to bypass the meanders of the tidal river. This lessened flooding in the valley and gave the river more strength to combat deposition. The banks of the new river mouth were secured by artificial embankments. HISTORY inates to the extent of some 80% condition of the licence is that the an average weight of 2—2.5 kg of the catchment. flow below the abstraction must ( 4 ‘/2-5 lbs) and some fish reach­ The headstreams o f the river are The impermeable clay of the not be allowed to fall below 4.543 ing sizes in excess o f 6 kg. The sea characteristically Wealden, dis­ Weald dictates the flashy character megalitres/day ( lm gd) in summer trout spawn in the gravels of the coloured by the vivid orange tinge o f the river, it responds quickly to and 9.086 megalitres per day northern tributaries in January o f iron. The valleys o f the catch­ rainfall which runs over the sur­ (2mgd) in winter. Other abstrac­ and February and the young or ment are studded with iron sites, face of the clay. The base flow is tions on the river are typically parr spend about two years in the marked by abandoned Hammer from the springs o f the Ashdown small. head streams. At a size of approx­ ponds and disused mills, testimony sands, but these are nowhere near imately 18 cms, the parr adjust to an industry long forgotten. as prolific as the chalk springs of their physiology in preparation for Names such as Furnace Lane, Hampshire and the South Downs WATER QUALITY sea water, and turning a silvery Boring House Farm, Cinderford which give their streams stability The National Rivers Authority sets colour, migrate to sea. The rich Lane and Steel Forge Farm are a of flow and temperature. The an objective that the Cuckmere feeding at sea enables them to lasting reminder of the ancient extremes of flow on the Wealden River should be of good quality grow rapidly until, as mature fish iron industry which brought pros­ streams may vary five-hundredfold and suitable for high class game they return to the river to join the perity to the area and reached its between summer and winter. As is and coarse fisheries (Class IB) winter spawning migration. peak in Tudor times. common in areas of Hastings Beds, above Sherman Bridge, and suitable Automatic weir and fish pass Iron Age man first extracted many o f the headwater streams for reasonably good coarse fish­ iron ore on the fringes o f the occupy quite deep valleys and the eries (Class 2 ) in the downstream Weald and used the bloomery pro­ streams themselves have carved section. The objective for the cess to create metal. The fast flow­ steep-sided channels. Waldron Gill between Vines Cross ing streams provided water to cool The overall amplitude of inland and its confluence with the Cuck­ tools and the solid mass o f iron relief is o f the order of 180 metres mere is also Class 2. These are “bloom ”. The Romans exploited with the downland escarpment known as Environmental Quality Wealden iron deposits for about which forms the southern boun­ Objectives (EQOs) and their par­ 200 years on a highly organised dary o f the catchment providing ticular importance on the Cuck­ scale, probably under the control an additional relief feature of up to mere River is to ensure that water o f the fleet. Large amounts were 230 metres. abstracted at Arlington for domes­ At the tidal limit, the Authority exported across the English The catchment has been gauged tic consumption is of high quality. has installed a fishway to help sea Channel. continuously at Sherman Bridge To ensure that the river water trout past the automatic weir The early bloomeries consisted since 1959 and this forms the long satisfies its objectives, the Author­ which separates the freshwater of a primitive furnace made of a term flow record for the river. ity sets limits on all permitted dis­ river from the tidal section. The clay walled mound of iron and Continuous measurements are charges to the river, restricting fishway is a sloping trough with charcoal. The draught was supplied also made on the headwaters near the strength and quantity of efflu­ baffles which reduce the velocity by bellows. The same process was Cowbeech and on the Bull River ents. These are known as consent o f the flow so that fish can swim used sporadically over a thousand at Lealands near Hellingly which is conditions. easily against it. Another fish pass years until the introduction o f the the main tributary. The two sites In the main, the river runs was provided in 1969 at Arlington blast furnace from France revolu­ have continuous records since through rural countryside and by the Eastbourne Water Com­ tionised the industry. This process 1967 and 1983 respectively. small villages which have remained pany to assist fish over the weir produced cast iron which could The average flow of the river at largely unchanged since being constructed in association with then be forged into wrought iron. Sherman Bridge over the period of listed in the Domesday Book. The the water works and reservoir. Water pow er was essential to the records is 1.5m5/sec. only major urban developments drive separate water wheels for Really long-term rainfall data is are Horam and Heathfield and the Community structure - fish biomass CowbMdi Bo ship Farm the bellows and for the forging lacking for the catchment but the only significant industry is cider hammer. The steep Wealden records that are available suggest making at Horam. The waste streams proved ideal for damming a catchment mean of some water from these towns is routed to create a head o f water. The sur­ 490mm. into Vines Cross sewage treatment rounding forest provided the fuel. How and rainfall information works, recently enlarged to cope enables the NRA to regulate the with heavy development in the amount o f water abstracted from area. There are a number of sewage GEOLOGY AND the river, through a licensing sys­ treatment works, both Water HYDROLOGY tem. This ensures that river water Authority and private which dis­ can be put to effective use for charge into the river, but stringent K ey The overall shape of the catch­ BT Brown trout. Bu Bullhead. Ch Chub. domestic consumption and agri­ consent conditions ensure that ment is quite distinctive, being D Dace, E F.els, M Minnows, ( ) Other, culture without harm to the river, the river still supports a high qual­ extremely narrow in relation to its P Perch. Pk Pike, R Roach and the wildife and fishes associ­ ity fishery. length and its geological cover ated with it. Unlike the cool chalk streams of shows considerable variety. Its At Sheepwash Bridge, just north Hampshire with water springing area to Sherman Bridge is 137.7 sq o f Cowbeech, an abstraction from deep underground reserves, km. In its course to the sea, the licence allows water from the the Wealden rivers are low and river traverses an almost complete underlying rocks to be pumped warm in summer. The high tem­ cross-section of Wealden geology’ into the Cuckmere River and to be peratures reduce the ability of the from Ashdown Sandstone through abstracted downstream at Arling­ water to carry oxygen, leaving the Weald Clay to chalk. Hastings beds ton where it is treated to provide river with a limited capacity to cover some 65% o f the area with drinking water. This is the largest absorb pollution. Agricultural Ashdown Sands predominating single abstraction on the river. A pollution is a constant threat, par­ and accounting for almost half of ticularly in the low Weald where the outcrop. In contrast the middle Checking water quality at Arlington reaches o f the catchment are marginal farmland is devoted pri­ floored by Weald Clay which marily to livestock farming. Water accounts for a further 22% o f the Quality Officers give high priority total area, with small tracts o f to farm inspections and to advis­ Upper and Lower Greensand, Gault ing farmers on the safe disposal of Clay and Chalk making up the re­ farm waste. mainder. Only a very small pro­ portion (2% ) o f the area lies FISHERIES under urban development, and In addition to sea trout, resident with woodland accounting for a The Cuckmere River supports a brown trout populations are further 18%, open land predom­ run of exceptional sea trout with found in the headwaters. The acid. principal tributaryvthe River which rises in a scenically beautiful area around Cross in Hand. Draining from the light sandy soils of the north, it flow s southwards to the stiffer Wealden clay, collecting the Darn Stream, the Possingworth Stream and the Chiddingly Stream before joining the main stream of the Cuckmere at Hellingly. From the high Wealden forest and the pastoral countryside of the low Weald, the river heads towards the gap it has can ed through the South Downs. At Upper Dicker, part of the river is diverted to form a 6 ‘/2 acre moat, one of the largest in England, at Michelham Priory (1229). At Arlington, the river is again diverted from its old course, where meanders are now occupied by a 120 acre bankside reservoir which supplies drinking water for the Eastbourne area. The river valley through the South Downs is dominated on its east bank by the L o n g Man of Wilmington, a 231 ft tall figure, possibly dating from the 6th Century, cut into the chalk. Below the present tidal limit at Milton Lock, the valley has been subjected to much embanking and drainage ditching. ITie mouth of the river at Exceat was only determined in ANDREW'S recent times, though the o word Exe is probably a pre- Saxon name for Cuckmere. iron rich streams support charac­ Further Reading teristically small but highly col­ McCarthy, E & M (1981) The Cuckmere. LindelPublishing Co., Seaford oured wild trout. The Cuckmere River also sup­ Survey o f Rivers and Coast in the South-East Region — The Rivers o f Sussex. ports a high quality coarse fishery. Nature Conservancy Council, Zealds, Church Street, Wye, Ashford, Kent TN25 5BW. In the steeper streams above the confluence of the Bull River and the Cuckmere River, chub and minnows are the characteristic species. Dace and perch appear in the middle reaches and in the lower, slow flowing reaches, still­ water species such as bream and carp predominate.

FLOOD DEFENCE Flood defence activities are con­ centrated mainly in the middle and lower reaches, though in the steep upper catchment there are several fixed weirs which must be maintained by the NRA or private owners. At Upper Dicker, a sluice gate owned by the NRA operates automatically in response to flow. An adjustable w eir at Sessingham can be lowered for winter flows and raised to retain summer levels. At the tidal limit, an automatic w eir rises and falls in response to flow and also prevents high tides flooding into the freshwater sec­ tion of the river. Additionally, it provides a head to supply the Freshwater Stream. This stream flowing parallel to the Cuckmere River on its way to the sea, pro­ vides drinking water for cattle in the water meadows of the flood plain. A great deal o f land reclamation has taken place throughout the valley and the extensive flooding Cuckmere Hov o f the past has been virtually elim­ inated. The NRA maintains the tidal fkxxJ banks and is responsible for 20 tidal flaps which protect streams and land drainage ditches Sections showing the general relations o f the rocks along the lines X— X', drawn on the map from the ingress o f tidal water yet Ragstone Vale of allow them to discharge at low Newhaven South Downs High W eald Vale of Kent Ridge Homesdale North Downs Isle of Sheppey tide. O.D. At Exceat, the constantly shift­ ing shingle requires regular atten­ tion. It is cleared from the river mouth to replenish the shingle beach to the west which acts as a Horizontal Scale about 1 -.250,000. Vertical Scale about ten times the Horizontal cushion against winter storms. A groyne system is maintained on ENVIRONMENT AGENCY this part o f the beach to retain the shingle. ^ el River? ' ;,iority {•icn C .. j \ J \ ffico _ 1s t

ftun Hythe Beds and 1 i <> n t T T T F m f H f . f U I f m n t j Atherfeid Cloy Southern Region Barton, BrocWesham and Boggshot Beds

Headquarters Upper Green sand Wealden Cloy Guildboume House Chatsworth Rood and Goult Worthing West Sussex BN 11 1LD Purbeck and Portland ~ I Claygate Beds and Tunbndge WeMs Sand, Beds, Kimmendge □Ashdown Beds and 1____ 1 London Clay < (0903)820692 February 1990 and Oxford Clay Wodhorst Clay