N A A S o o 4V\z /v \ ^ - 5 THE RIVER TEST E n v ir o n m e n t A g e n c y NATIONAL LIBRARY & INFORMATION SERVICE SOUTHERN REGION Guildbourne House, Chatsworth Road, Worthing, West Sussex BN 11 1LD NRA ational Rivers Authority Southern R egion Guardians of the Water Environment ENVIRONMENT AGENCY 054505 and grist milling and the divisions, these being the flows do not have the support THE generation o f electricity, though Upper, Middle and Lower Chalk. of resilient springs. none o f the traditional mills The first outcrops over much For these reasons, chalk have survived in working of the catchment but there are streams characteristically have RIVER condition. some exposures of Lower few tributaries compared with There are still extensive Chalk, particularly in the North rivers draining impermeable TEST remains o f the water meadow West above St Mary Bourne. areas. The drainage densities of system, which was used to fkxxl From Mottisfont southwards the Test and Itchen (km of fields with the relatively warm there are younger rocks of stream/sq. km of land area) are river water in the early months Tertiary origin. These are a around 0.12 compared with of the year to promote an early mixture of silts, clays and sands values of up to 0.47 for the COURSE AND growth o f grass. The tempera­ which are much more im­ clay-vale rivers of Sussex and ture o f chalk streams is always permeable than the Chalk. Kent. HISTORY higher than soil temperatures There is an important inlier of The actual line of the River The River Test is probably the in the winter months due to Tertiary rocks into the Chalk Test and its tributaries falls most famous chalk stream in the large groundwater to the West of Kimbridge over approximately on a right angle southern England, draining a component. “Carriers” along which the River Dun flows. grid pattern, reflecting the way surface catchment of some the sides o f valleys were used The landscape of the area the chalk was flexed by geo­ 1,260 sq. km. It rises in the to flood the meadows and the was shaped in the last Ice Age. logical movement. Upper Chalk near the village of water was returned to the river The precise origin of the dry The NRA measures flows at a Ashe, East of Overton and soon via low level “drains”. Many of valleys in the rolling Chalk number of points using specially collects a handful o f small these larger channels still exist Downs is still uncertain, but designed weirs. There are spring-fed tributaries on its but the system became derelict they were probably formed by gauging stations on the River passage southwards; the Bourne with changes in agricultural stream erosion when the Anton at Fullerton, on the Rivulet, the Dever, the Anton, practice and because it was ground was frozen, causing Wallop Brook at Broughton the Wallop Brook and the labour intensive. rainfall to run over the surface and on the River Blackwater at Sombourne Stream. From the Between Timsbury and rather than soaking into the Ower. upper reaches the river widens Romsey a stretch of the chalk. The main long term flow considerably and meanders Andover - Romsey - Redbridge Apart from evaporation, records (since 1957) is from through a wide floodplain, Canal still exists. This canal almost all of the 824 mm of Broadlands where average flanked by water meadows. was authorised under a private annual rainfall that falls on the flow is 11.8 mVsec (224 mgd). Within its broad valley it fre­ Act o f 1789 and was 22 miles Chalk catchment soaks into its More recently an electro­ quently splits to form a network long with a fall of 176 feet. In deeper layers which are fully magnetic gauging station has o f braided channels. From Mot- the early part o f the 19th saturated with water. The been installed at Testwood. tisfont southwards, the Test Century' an attempt was made water moves through the flows over less permeable soils to build a canal from Salisbury Chalk under the influence of and rocks and is joined by the to join the Andover Canal at gravity until it issues from River Dun, Tadburn Lake, Mottisfont but it was never springs in the valley bottoms, Greenhill Lear and the Black- successful. feeding the river system with WATER water. The wide fkxxlplain Peat has been dug for fuel in high quality water. continues to the tidal marshes a number of places and there The National Rivers Authority RESOURCES between Testwood and Red­ are “peat holes” on the North collects information about the The development of South bridge where the river outfalls side o f the Houghton-Horse- groundwater and its fluctu­ Hampshire, based historically to Southampton Water. bridge Road and the large ations using a network of over on rail and sea links, but more The Hampshire Rivers were pond near Marsh Court has the 440 wells and boreholes in the recently on the improved road once tributaries o f the ancient same origin. Test catchment. network, has generated a con­ Solent River which flowed east­ Generally rain takes several tinuing demand for water for wards from the River Frome to months to find its way through domestic and industrial use. join the sea somewhere near the Chalk to the springs, so the The Water Act 1989 gave Littlehampton in times when winter rainfall which swells the NRA the duty to ensure the Isle o f Wight was part o f GEOLOGY AND the underground reserves gives that water resources are the mainland. This trunk river peak river flows in late spring conserved and managed system was dismembered HYDROLOGY and through the summer. With properly. Consequently the during the Pleistocene Period The underlying rocks of the slight variation in flow between Authority will play an im­ when the sea made inroads Test catchment form part of seasons, the river has created portant role in balancing the into the catchment to the East the northern flank of the very little freeboard to the top needs of the environment with and West o f the Isle of Wight. Hampshire Basin, a geological of its banks. those of the water user in the More recently, the activities feature in which the rocks Although the range of flows face of future development. o f man have shaped the River slope gently or dip from the is slightly higher than the The prolific chalk streams Test. The braided channel North to the South. The oldest neighbouring River Itchen, provide much of the water system is a legacy o f the historic rock is the Cretaceous Chalk maximum flow in any year is used in Hampshire, particularly uses o f the river for milling for which outcrops over the whole typically only 4-5 times the from their lower reaches. land irrigation of “water o f the valley to the North of minimum. This contrasts Some water is also pumped meadows” and for navigation. Mottisfont. This is a porous sharply with the Wealden from boreholes penetrating The river once provided fine grained limestone which rivers where surface run-off in the chalk aquifer. power for wool processing, is generally very permeable. winter can boost flows several The NRA is now the licens­ paper making, tanning, flour There are three main sub­ hundred times, and summer ing Authority for all abstrac 11. lur; % tions and considers the environmental aspects of a , FINja^=dOWN rsto k e \\ 7\J proposed abstraction and its ieCe PK. m a o v e i\ rhittihurch 'e s to n effect on other lawful water DoW li 03400 IfiaJrick 'HITCHTCfcflCH users. In order to protect over­ SILK M „ flows, restrictions are attached to licences to ensure that water is only taken from speci­ la ris h fied locations and at times ? a River Anton, Upper Clatford when it can be spared. i arewi Forest An important consideration : h e d / - ^ ^ u is the extent to which the ILLAC water is returned to the river Xgrwell ton and the point of its return. >tacey Water taken out of the catch­ ment or “consumptive use” is a teas loss to the river system. Some lilbortfi.n ille rto r iB3420 uses such as spray irrigation lTElLITSj:RACKIN< Over (atercr* STtf- are entirely consumptive lA/ o I I n r i f fid d le FISH .e c k fo rd because of evaporation or Chapmansford Farm, Bourne Rivulet & HATCHEF export out of the catchment. Conversely almost all water­ ton cress growing, gravel washing, Lof and fish farming abstractors jrn e return all the water to the tY RING fockbridj same location, so overall effects Fort) fil Coaching Tq on flow are small. On average, TVIidrfle h o u g w jo i; 80% of water abstracted for (slov jgnton l o d g e domestic supply is returned to W inter£lov the river after proper treat­ ment. On the River Test con­ Pitton Comnjio'f & sumptive use represents only W ast King's'; 2% o f total average flow. Tythiw le^ So m borne' The major abstraction for H O R i public water supply at Test­ MONUMfNTl wood is located close to the tidal limit so that water is taken just before it is lost to the estuary. The licence ensures fliv e r/ '< MIZ- MA'iE that sufficient flows are pre­ M ^RDONI c) B^wry 4 served for the needs of migra­ C om p tc tory fish.