Bass, J.A.B.

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He `52-b ri,/) 0 Juk._`1InstituteFreshwati' cb5 CEcologyNatural Environment Research CouncilA biological assessment of three drainagechannel sites near Kings Lynn, NorfolkReport to - Hepworths Minerals and ChemicalsJ.A.B. BassINSTITUTE OF FRESHWATER ECOLOGYEastern Rivers LaboratoryMonks wood Experimental StationAbbots RiptonHuntingdonCambs PE17 2L5Project Leader W.DavisonReport Date: July 1990IFE Report Number: ERG/T11052b5/1TFS Project Number: T11052b5This is an unpublished report and should not be citedwithout permission, which should be sought though theDirector of the Institute of Freshwater Ecology in the firstinstance.The Institute of Freshwater Ecology is part of theTerrestrial and Freshwater Sciences Directorate of theNatural Environment Research Council.INTRODUCTIONThe discharge of pumped groundwater via settlement lakesinto a receiving water course is proposed by HepworthsMinerals and Chemicals.An assessment of the impact on two•potential receiving watercourses is required.This report describes the freshwater invertebrates( identified to Family level ) and general features of threesites on small drainage channels near Kings Lynn, visited on4 July 1990.The analysis of corresponding water samples is recordedin a separate report ( by Dr. W. Davison )SITE LOCATIONSGaywood River, National Grid Reference TF 664209 Middleton Stop Drain, N.G.R.TF 633192 Middleton Stop Drain, N.G.R.TF 641188SITE DESCRIPTIONSGeneral — The three sites are on channelised streamswhich have been straightened and the high banks are steeplygraded.Gaywood RiverSite situated about 3.5 Km east of Kings Lynn and 1 Kmnorth of Mintlyn Wood. Channel width at water surface about3.5 m, water depth about 0.75 m. Extensive fine siltdeposits, including an ochre deposit, covered the streambed. Sparse growths of submerged Callitriche sp.,Potamogeton sp. with emergent stands of Rorippa nasturtiumaquaticum and Phragmites communis were also seen.Middleton Stop DrainSite in the Hardwick Industrial Estate on the south eastfringe of Kings Lynn. Channel width about 4 m, water depthabout 0.5 m. Surface water drains from the industrialpremises discharged from pipes at frequent intevals alongthe bank ( the visit coincided with heavy rainfall ). Nowater plants seen. Flocculent, highly organic, sedimentdeposits were of a black, anoxic. material. A surface filmof oil was present.3.) Middleton Stop DrainAt the A149 road bridge about 1.5 Km south east of KingsLynn. Channel width about 5 m, water depth about 0.75 m.Plants were restricted to some isolated Sparganium emmersumand bankside Phragmites communis. Deep soft sediments ofsilt and clay covered the stream bed. Some oil was seen onthe water surface.WATER VELOCITYWater velocity measurements were taken using anelectromagetic flow meter ( Armfield Technical EducationLtd ) at site 1. The deep fine sediments at sites 2 and 3prevented wading to record velocity profiles.At site 1 a velocity profile was recorded under abridge where the channel width was 3m, with a mean waterdepth of about 0.3m. Velocities were measured at ten pointsacross the stream at 0.6 of the depth, values ranged fromzero to a maximum of 0.157 m sec-1 . Mean velocity was0.048 m sec-1 with a discharge rate of 43 litres sec-1 .Lower velocities and discharges were subjectivelyconsidered to be prevailing at sites 2 and 3 on 4 July 1990.FRESHWATER INVERTEBRATESIdentification was to Family level and a log scale ofabundance in a standard collection interval of 20 secs isindicated ( 1-10 - "1", 10-100 - "2", 100-1000 = "3", 1000-10000 - 114").Only aquatic fauna was recorded and the appropriate"score", as used in the Biological Monitoring Working Party(BMWP) classification system was applied ( i.e. a pollutiontolerant taxon rates a low score ).Total "scores" for each site and the "average score pertaxon" (ASPT) ( total score / number of Families recorded )are given ( Table 1 ). These are used to assess theinvertebrate community present.1.) Gaywood RiverThenty scoring and three non-scoring Families were found,Total Score and ASPT were 81 and 4.05 respectively. Thelarvae of the large mayfly, Ephemera danica was the onlyhigh scoring invertebrate recorded and was confined to thissite. The remaining range of invertebrates, the Total Scoreand the ASPT were lower than would be anticipated for anunpolluted lowland stream.Middleton Stop Drain ( Industrial Estate )Just two low scoring Familes were recorded, theOligochaeta ( worms ) and larval Chironomidae ( non—bitingmidges ). The anoxic sediment would provide suitableconditions for few invertebrates.Middleton Stop Drain ( A149 bridge )Eight scoring Families were found and empty shells of twomollusc Families were present. Consequently there was a lowTotal Score of 32 and a similar ASPT to that found at site1.CONCLUDING REMARKSInvertebrate samples, water velocities and watersamples taken on one occasion provide only a single "snap—shot" of conditions pertaining at the three sites.The contrast between the range of invertebrates at site1,2 and 3 suggest that Middleton Stop Drain, both upstreamand, particuarly in the region of the Hardwick Industrialestate, receives some polluting imputs.The highly organic nature of the sediments at site 2.and absence of ochre deposits suggest that pollution isderived from sources unrelated to the discharge ofgroundwater Vid the Mintlyn River.The discharge of neutralised or moderately acidicgroundwater via the Mintlyn River is unlikely to causefurther deterioration in the faunal assemblage of the slowflowing Middleton Stop Drain. The effect may be theprovision of greater dilution of other effluents enteringMiddleton Stop Drain.The Gaywood River has a higher ( estimated ) flow ratethan Middleton Stop Drain, providing greater dilution for aneffluent . An assessment of stream flow and bufferingcapacity in relation to the risk of increased deposition ofochre deposits would be appropriate, before the consequencesfor the invertebrate fauna were predicted.TABLE 1 (9)wveRfloa/i-re/AM SLYa H pi) PSlit-ScoRE. t 2. 3-4 , •Oat BY I / 3 ziscicolidae11 PsihoniidaeB53 1drudidaeBI..,oadellidaeB.3 I1.*:J21./iia 6. ciephiidaeA6-, „oxides A 6 31'Ise1IIenuridaee•a1to hleblidaeA 6lohemerellidae12otamAnthidae128phemeridae129to 1Caenidae1564 4-etidae44e:Itidao.-%.da1T-hidae•...._N.IrdulsteridaeA fiIeachnidae Aorduliidae-152datA53etnenidida. A.eenaAriidardae,.9ialiciae 34 4- 2IalatenterygidaeA301 -uotridaeA 1annfidae 132se-lodidaePerlidaeAikhl ro-DprlidaeAlS.1 lehrvaneidaeA,.nndaeA ;.72.1.51ig.Ae A ;CdentoceridaeL'Inteceridae.,r d:o•'9 4.3+ ratid,0r3eh7eentridaeMgS..ieestomatidae11—r-thomvid.AelaFh lo .tamidaeARhyaceshilidaeAO_rolloAntroeidaqA59LInnenhilidae160F7dro.tilidaeA.Hydrercychidae13140TABLE 1 (3)IIN0/621-ie&PA-FtFAH' ett6)4cofSilt.scoal; I 2. 3IRaliplidaeE29 5 I-robildn.eBpI4tseis40%r.1Ridae 73.12Bydrophilidae3331IClambidao3341 1111111111'Noloadae33>apuonidae3411ElminthidaeB7c I'ChrocelidscBACuroulionidae11391,AphelocheiridaeA •IMeaovolidae£70IIRydrometridae£71111111111Cerridae£72NepidaeNaucorfaaet25Notonectidae326111111111111111111Pleidae32or•4032; 51,Tipulidae•noi SimuliidaeB12 5Chironomidae$82 3NeritidaeA61I ViviparidaeA62AncylidaeA63.._UnionidaeA651SphaarildaeB53atadsLt4'Valvatidae11148$2drobiidaeB49impaeidae350 39 tiyoloaeB 1 3IPl:Lnorbidae3523111I4 Porifera \1 PolyzoaNemntoda4 CladoceraincopepodaICstrtoodaIitarSliumIV3ilidacPrechoddaCPratcoortnidae'CulicidaeS-rohidaeMu::cidaeEzoididaedr,:,nellidae 7-Halacaridae1.,treissonidae-re-4/4^/d-1-TAXA Rio81-61-AL StaRE set 3 37_AVERAat- SCERercit-10X 4-05 I-5o Woo

A biological assessment of three drainage channel sites near Kings Lynn, Norfolk

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A biological assessment of three drainage channel sites near Kings Lynn, Norfolk

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