The River Test
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NRA Southern 38 THE RIVER TEST Is Authority NRA ' t i n t r e National Rivers Authority Southern Region Guardians of R c u r L the Woter Environment and grist milling and the divisions, these being the flows do not have the support generation of electricity, though Upper, Middle and Lower Chalk. of resilient springs. THE none of 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 of the water meadow West above St Mary Bourne. areas. The drainage densities ol system, which was used to flood 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 growdi of grass. The tempera which are much more im clay-vale rivers of Sussex and ture of 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 of 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 of 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 m3/sec (224 mgd). Within its broad valley it fre- Act of 1789 and was 22 miles Chalk catchment soaks into its More recently an electro quenUy splits to form a network long with a fall of 176 feet. In deeper layers which are fully magnetic gauging station has of braided channels. From Mot- the early part of 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 (.anal at gravity until it issues from River Dun, Tadburn Lake, Mottisfont but it was never springs in the valley bottoms, Greenhill I^ear and the Black- successful. feeding the river system with WATER water. The wide floodplain 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 of 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 of 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 of Wight was part of 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 of 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. of 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 of the historic rock is the Cretaceous Chalk maximum flow in any year is used in Hampshire, particularly uses of the river for milling, for which outcrops over the whole typically only 4-5 times the from their lower reaches. land irrigation of “water of 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. pow'er 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- tions and considers the environmental aspects of a ,loro FINfctfg^tfOW proposed abstraction and its )\ iece p k effect on other lawful water *ndovei% DO/Wli B3400 users. In order to protect over irstlft flows, restrictions are attached to licences to ensure that OV£RPriors water is only taken from speci fied locations and at times when it can be spared. forewc An important consideration Forest :heoj is the extent to which the ILLA< water is returned to the river Iry'ffuins) X e rw e lt and the point of its return. Water taken out of the catch ment or “consumptive use” is a loss to the river system. Some uses such as spray irrigation Over C a terer! are entirely consumptive lA/olln f i s h r 1 because of evaporation or Chapmansford Farm, Bourne Rivulet H A T C H E f export out of the catchment. ‘EBURY ^angstock Conversely almost all water cress growing, gravel washing, and fish farming abstractors River Dever at Barton Stacey return all the water to the fockbrid; same location, so overall effects Coaching To J j m m m m Old on flow are small. On average, re s fo rd ■ HOUGh^Oi; 80% of water abstracted for ighton l o d g e che^i FULk domestic supply is returned to tokq] m ii Wintejr^slov W A T t the river after proper treat ment. On the River Test con Pitton ^ Comrior sumptive use represents only W ast K in g 's 2% of total average flow. T ythor lev JSom borne J r e s f o r d f k The major abstraction for IB 3046 public water supply at Test wood is located close to the Brook tidal limit so that water is taken just before it is lost to the estuary. The licence ensures ^ Star '< MIZ M A *E that sufficient flows are pre "tvltthelna^rsh ][ ^ y / , r ' ] served for the needs of migra f ^^Braishfi|ld' tory fish. Ha ®L ford; Abstraction licensing was introduced by the Water n r ( < - r A \ X W HILLIE Resources Act 1963 which was angri AR 8 0 RE ftt( the first statute to control the C l amounts of water taken from gan s rivers. At that time established He NEV abstractors were given “Licen .OLD ces of Right” to continue taking W INCHESTER HIL WOW/ \ A2? X O N r — IA L ^ water at the existing rate and L O R f N C E at the same location.