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CatchmentManagementEvidenceReview

WATER QUDŽLIǝ Y

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Bringingpeopletogethertounderstandhowtoachieveabetter moresustainableenvironment COLLABOR8 is a transnational European project, funded by the Interreg IVB North West Europeprogramme,whichaimstocontributetotheeconomicprosperity,sustainabilityand cultural identity of North West Europe in increasingly competitive global markets. This is beingachievedbyformingandsupportingnewclustersinthecultural,creative,countryside, recreation,localfoodandhospitalitysectorsusinguniquenessofplaceasabindingforceand overcomingbarrierstoregionalandtransnationalcollaboration.

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“Wateristhedrivingforceinnature.� LeonardoDaVinci

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The Upstream Thinking Project is South West Water's ƪagship programme of environmental improvements aimed at improving water quality in river catchmentsinordertoreducewatertreatmentcosts.Runincollaborationwitha groupofregionalconservationcharities,includingtheWestcountryRiversTrust andtheWildlifeTrustsofDevonandCornwall,itisoneoftheƤrstprogrammes intheUKtolookatalltheissueswhichcaninƪuencewaterqualityandquantity acrossentirecatchments.

Publishedby: WestcountryRiversTrust RainCharmHouse,KylCoberParc StokeClimsland Callington CornwallPL178PH Tel:01579372140 Email:info@wrt.org.uk Web:www.wrt.org.uk © Westcountry Rivers Trust: 2013. All rights reserved. This document may be reproduced with prior permissionoftheWestcountryRiversTrust.

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CONTNJNǝS Introduction 









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o Freshwater:avitalecosystemservice o Pressuresaơectingwaterquality  o Factorsthatdeterminepollutionrisk  o Thecatchmentmanagement‘toolbox’ o Assessingtheeƥcacyofinterventions

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PollutantSummaries 





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o Nutrients&algae   o Suspendedsolids&turbidity o Pesticides    o Microbes&parasites  o Colour,taste&odour 

    

    

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Assessingimprovements





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Governance&planning





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INTƺOD8CƼƮON

Fresh watʑɠ: Ɉ viWɪl ecoʣyVtʑm ȿʑʢviȪɏ Rain falling on the land brings life to the plants and animals living upon it, but it also collectsandrunsacrossthelandformingrills,gullies,streamsandultimatelyrivers.The transfer of fresh water onto and then across the land is one of the fundamental processes that sustain life on Earth. All of us depend on the fresh, clean water in our rivers and streams every day – we drink it, we bathe in it and it sustains other life on whichwedependforfoodandenjoyment. TargetsfortheacceptablelevelsofpollutantsinfreshwateraresetoutintheEuropean Commission’s Directive on the Quality Required of Surface Water Intended for the Abstraction of Drinking Water 1975 (75/440/EEC)and,morerecently,intheEuropean Commission’sWaterFrameworkDirective2000(2000/60/EC). While the former EC Directive refers to the quality of raw water intended for human consumption, the latter sets targets above which it is expected that the ecological conditionofawatercoursemaybedegraded. In addition, Article 7 of the Water FrameworkDirective (2000) also stipulatesthat, for ‘watersusedfortheabstractionofdrinkingwater’,waterbodiesshouldbeprotectedto avoid any deterioration in water quality, such that the level of puriƤcation treatment requiredintheproductionofdrinkingwaterisreduced.

While for most pollutants there is no inevitable link between the quality of raw and treateddrinkingwater,thelevelofcontaminationinrawwaterisdirectlylinkedtothe diversity,intensityandcostofthetreatmentsrequired. Furthermore, there are certain pollutants or physical characteristics that, when they occurintherawwater,canseverelyaơecttheeƥciencyofthedrinkingwatertreatment process.Whenthesepressuresdooccur,orwhenthewatertreatmentprocessdoesnot takeaccountofaspeciƤcpollutantorgroupofpollutants,therecanbeanincreasedrisk thatthetreateddrinkingwatermayfailtoreachthedrinkingwaterstandardsrequired atthepointofconsumption(thetap).

PreVʣureɡ ɈՔecʤʖng watʑɠ qXɪʙiʤɨ Aquaticecosystemscanbedamagedordegradedbyawidevarietyofpressures,which ariseeitherfromhumanactivitiesbeingundertakeninspeciƤclocations(pointsources) or from the cumulative eơects of many small, highly dispersed and often individually insigniƤcantpollutionincidents(diơusesources). Highly localised, point sources of pollution occur when human activities result in pollutantsbeingdischargeddirectlyintotheaquaticenvironment.Examplesincludethe releaseofindustrialbyǦproducts,eƫuentproducedthroughthedisposalofsewage,the overƪowsfromdrainageinfrastructureoraccidentalspillage. Superimposed on the pressures exerted by point sources of pollution are the more widelydispersedandlesseasilycharacteriseddiơusepollutionsources. When large amounts of manure, slurry, chemical phosphorusǦcontaining fertilisers or agrochemicalsareappliedtoland,andthiscoincideswithsigniƤcantrainfall,itcanlead torunǦoơorleachingfromthesoilandthesubsequenttransferofcontaminantsintoa watercourse. In addition, cultivation of arable land in particular ways or the over disturbance of soil by livestock (poaching) can make Ƥne sediment available for mobilisationandsubsequenttransfertodrainsandwatercoursesbywaterrunningover thesurface. OtherdiơusesourcesincludetherunǦoơofpollutantsfromfarminfrastructuresuchas dungheaps,slurrypits,silageclamps,feedstorageareas,uncoveredyardsandchemical preparation/storageareas. Animal access to watercourses can also lead to the direct delivery of bacterial and organic compounds to the water and to their reǦmobilisation following channel substrate disturbance. It should be noted that, while these agricultural sources of pollution can often appear more like point sources, they are, however, considered as diơuse sources as they relate to widespread, landǦbased, rural practices that that can havesigniƤcantcumulativeeơects. 6


Pollutantsthatexertnegativeimpactsonthequalityoffreshwater,degradethehealth of our aquatic ecosystems and contaminate raw drinking water are numerous and varied.Forthisreview,thesepollutantsarecategorisedunderƤvemainheadings:

Nutrients.Phosphorus&nitrogenǦcontainingcompounds Suspendedsolids.Includingbothsediment&organicmaterialinsuspension Pesticides.Includingotherchemicalpollutantsfromdomesticsources Microbiologicalcontaminants.Includingfaecalcoliforms&cryptosporidium Colour,taste&odourcompounds.Includingmetals&solubleorganiccompounds

FacWʝUɡ ʃKaɢ detʑʢʛʖȸɏ pɼɸʙXʤiʝɚ ʢisk There are a number of factors in the landscape that determine the degree to which a pollutant will become available in a particular location and the likelihood of it being mobilisedandcarriedalongapathwaytoawatercourse.

Some soils, such as heavy clayǦ or peatǦbased ‘stagnogleys’, are more susceptible to damage,suchascompaction,causedbyintensivecultivationorlivestockfarming.This increasestheriskoferosionorsigniƤcantsurfacerunǦoơoccurringfromtheirsurface. Other soil types, such as lighter, freeǦdraining ‘brown earth’ soils, can have pollutants leachedawaybywaterpassingrapidlydownthroughthem.Inaddition,soilswithvery high levels of organic matter, such as peat, can release large quantities of organic compoundswhentheyaredrainedortheirstructurehasbecomedegraded. In light of this, it is clear that careful and appropriate management of soils can be a powerfulmethodforminimisingtheriskofpollutionoccurringasaresultoftheirinnate structuralvulnerability. Topography&hydrology Theshape(morphology)ofthelandinteractswiththeunderlyingsoiltypeandgeology to control the movement of water across the landscape. Some of the waterfalling on thelandasrainwillbeabsorbedintothesoilfromwhereitcanbetakenupbyplantsor passdownintothegroundwaterheldintheunderlyinggeology. When the soil is saturated or damaged or the underlying rock is impermeable, water stops being absorbed and begins to move laterally across the land via surface or subǦ surface ƪow. Once moving through the landscape, water then collects in rills, gullies, drainsandditches,beforeenteringourstreamsandriverstomakeitswaybackthesea.

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Theriskthatanareaoflandposesto theprovisionofanecosystemservice, suchastheregulationofwaterquality, canbeconceptualisedasthe interactionbetweentheinherent characteristicsofthelandandthe activitiesorpracticesbeingundertaken uponit.Therefore,itispossibleto identifyareaswherepotentiallyrisky practicesarebeingundertakenand wherethiscoincideswithahigh underlyingriskthatwaterqualitycould bedegraded.ThesehighǦscoringareas canbeconsideredthepriorityforthe targetingofcatchmentmanagement interventionsandalsowherethe greatestenhancementofecosystem serviceprovisionmaybeachieved.

PRACTICE

Soilcharacter&condition Thecharacteristicsandconditionofthesoilinaparticularareabothplayakeyrolein the ability of the land to regulate the movement of water and the likelihood that pollutantswillbecomeavailableformobilisationintoadjacentaquaticenvironments.

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INHERENTRISK


Incertainareasacrossthelandscape,wheretherearesteepconvergingslopesorwhere the land is ƪat, water will naturally accumulate more than in other areas. In these ‘hydrologically connected’ or ‘wet’ areas there is an increased likelihood, particularly during periods of heavy rainfall, that water will run rapidly across the surface and mobiliseanypollutantsthatareavailableonthelandsurface. Given the fact that certain areas, due to their morphology, have an elevated level of hydrological connectivity and an increased probability that water will ƪow laterally across their surface, it is vital that we identify them and design tailored management interventionstomitigateanyriskthattheymaygeneratepollution.

Hydrologicalassessmentofarivervalley

LandǦuse&landǦcover The use to which a parcel of land is put can have a signiƤcant eơect on its ability to regulate the movement of water across it and the likelihood that it will generate pollutionintheaquaticenvironmentsnearby. Naturalhabitatshaveroughersurfaceswithmorecomplexvegetation.Theytherefore havearelativelylowriskofbecomingapollutionsourceastheyaremorelikelytoslow the movement of water across the landscape, increase inƤltration into the soil and increasetheuptakeofwaterbyplants. In contrast to natural habitats, land in agricultural production experiences greater levelsofdisturbance,whetherthroughcultivationortheactionsoflivestock,andthere is therefore greater risk that it will become damaged and become susceptible to erosion,pollutantwashǦoơorpollutantleaching. Whileitiscertainlynotalwaysthecase,theriskofpollutionoccurringisgenerallyhigher where land is in arable crop production or under temporary grassland. This is simply because the presence of bare earth for longer periods and the high intensity of cultivationundertakenonthislandincreasesthelikelihoodthatthesoilconditionmay bedegradedandpollutantmobilisationmayoccur. Landunderpermanent grassland (pasture)inherentlyrepresentsalowerpollutionrisk duetoitsundisturbedsoilandmorematurevegetation.However,eventhislandusecan generatesigniƤcantlevelsofpollutionwhenitssoilsurfacebecomesdamagedbyhigh livestockdensityorwhenlargelevelsofnutrientsorpesticidesareappliedtoimproveit. Whenassessingtheriskthatdiơusepollutionmayoccur,therearealsoareasofurban and industrial landuse that should not be overlooked. SigniƤcant levels of pollutants (such as sediment, oil, metals, pesticides and a variety of other chemicals) can be mobilised from the often impermeable surfaces and drainage systems connected to watercoursesinurbanenvironments. In light of these diơerences in the ability of diơerent landǦuses and landǦcovers to generate pollution, it is clear that either changing landǦuse or ensuring that best managementpracticesareundertakenoneachparticularlandǦuserepresentthemost importantmethodsforthemitigationoflandǦusedrivenpollutionrisk. 8


Practice&landmanagement While soil characteristics, morphology, hydrology and landǦcover all contribute the innatepotentialforlandtogeneratewaterpollution,itisultimatelythemanagementof landandthepracticesthatareundertakenuponitthatwilldeterminethelikelihoodand scaleofanypollutionthatoccurs. Theintensityandtimingofouractivitiescanaơecttheabilityoflandtoretainpollutants andsoincreasethelikelihoodofpollutionarisingfromit.Theriskofpollutionoccurring canbeincreasedwhenlandisoverǦstockedwithlivestockinvulnerablelocationsorat timesofelevatedriskduetotheincreasedchanceofheavyrainfall.Theriskcanalsobe increased when land is drained, compacted with machinery or when it becomes damagedbyrepeatedcyclesofintensivecultivationandcropproduction.

PaulAnderson

Furthermore,theexogenousapplicationofadditionalmaterials(manureandslurry)and chemicals(pesticidesandfertiliser)tothelandcanincreasetheavailabilityofpollutants incertainareasattimeswhenthereisincreasedlikelihoodthattheywillbemobilised andtransportedintoaquaticecosystems. Finally,itisalsoimportanttoconsidertheimpactsthatotherhumanpractices,suchas recreationalanddomesticactivities,canhaveontheconditionofland,theavailabilityof pollutantsincertainareasatcertaintimesandtherisktheyposetothewaterquality.

CDŽSE SƼǟLjY Mʋpʠʖng ȴʑɨ ʋreaɡ fʝɠ ʃȱɏ ʠUʝviʣiʝɚ Է ʓresh watʑɠ aɡ ʋɚ ecoʣyVtʑm ȿʑʢviȪɏ Thereareareasoflandwhere,duetothephysicalcharacteristicsofthelocationorasuddenchangeintheweather,any landmanagementpractice,irrespectiveofwhetheritisinherentlyriskyanddespitebestpracticebeingobserved,can stillresultinthegenerationofpollution.Onthishighpriorityland,thereisthegreatestlikelihoodofwaterqualitybeing degradedandfortheecosystemservicesdependentonittobecompromised.Inaddition,thesearealsotheareaswhere thegreatestenvironmentalbeneƤtsmayberealisedfortheminimuminvestment. Throughcombiningdataonsoilcharacteristics,landuse,landtopographyandhydrologicalconnectivitywecancreatea mapoftheseinnatelyriskyandthereforethemostimportantareasoflandinacatchment(theexamplebelowshows andanalysisofthistypeperformedontheTamarcatchment).

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A CaWɭʕȷʑnɢ MʋnaȰʑȷʑnɢ Toɼɸbʝx Ifwecandeterminewhichpressuresareexertingnegativeimpactsonthewaterquality in our aquatic ecosystems and identify their sources in a catchment, then we can develop a programme of tailored and targeted interventions to remove these sources anddisconnecttheirpollutionpathways. Formanypointsourcesofpollution,thescaleoftheircontributiontothepollutionload in a watercourse can be characterised through monitoring and modelling approaches andthenregulatoryandtechnologicalmeasurescanbeimplementedtomitigatetheir impacts. In contrast to point sources of pollution, the various sources of diơuse pollution in catchmentsarefarhardertoidentifyand,individually,theirimpactsareoftentooslight, intermittent or transient to quantify with great accuracy and certainty. Despite these challenges,however,thereisnowawealthofevidenceanddatawhichdoallowthese diơuse sources of pollution to be identiƤed and for programmes of interventions and measurestobedevelopedtomitigatetheirimpacts. Over the last 10Ǧ15 years a comprehensive suite of land management advice and onǦ farm measures has been developed to minimise loss of pollutants from farms while maximising eƥciencytoincreaseyieldsandsavecosts.Someof themostcommonof thesesoǦcalledBest Farming Practices (BFPs)thatarenowrecommendedtofarmers, and which are now being delivered on farms across the UK, are illustrated on the followingpage. Therearenowmanyorganisationsthathaveskilled,knowledgeableandhighlyqualiƤed farm advisors who are able to give advice on farming practices, including; Catchment SensitiveFarming,RiversTrusts,WildlifeTrusts,SoilsǦforǦProƤt,NaturalEngland,the EnvironmentAgencyandtheFarming&WildlifeAdvisoryGrouptonamejustafew.In addition, land managers also obtain a considerable amount of advice from their own agronomistsandfarmingadvisors. What is clear is that, irrespective of who is delivering an integrated farm advice and investment package, it should cover a broad spectrum of land management practices andindicatewheretheadoptionofgoodorbestpracticemayminimisetheriskthatan activitywillhaveanegativeimpactontheenvironmentandwhereitmayenhancethe provisionofanecosystemservicesuchaswaterqualityprovision. During the development of the onǦfarm intervention toolbox there were a number of key design considerations taken into account, which allow a farm advisor to correctly tailorandtargettheirapplication:Ǧ

 Mechanism of action. It is important to understand the mechanism via which the interventionwillreducepollution.Oftenthiswillrequirethepresentationofevidence that it is the farming practice that is causing pollution before intervention is undertaken.

 Applicability.Eachmeasuremusthavethefarmingsystems,regions,soilsandcrops to which it can be applied clearly deƤned. Farm advisors must recommend interventionsthataresuitableforthesituationfoundonaparticularfarm.

 Feasibility.Theeasewithwhichthemeasurecanbeimplementedandanypotential physical or social barriers to its uptake or eơectiveness must be identiƤed. Careful considerationmustbegiventomeasuresthatmayimpactotherfarmingpractices.

 Costs&beneƤts.Thecostofimplementing,operatingandmaintainingthemeasure must be clearly understood. The potential practical and Ƥnancial beneƤts to the farmer of implementing the measure must also be estimated as it is vital for encouraginguptakeofthemeasures.Insomecircumstances,wherethecostishigh orthemeasurewillresultinalossofincome,thefarmerorfarmadvisormayneedto Ƥndadditionalfundingfromincentiveorcapitalgrantschemestoenabledelivery.

 Strategically targeted. The measures need to be delivered into situations where theyaremostlikelytohavethedesiredwaterqualityoutcome.Byensuringthatthe rightinterventionistargetedontothemostsuitableandappropriateparcelofland, the likelihood that the most costǦeơective use of the investment has been made increases – i.e. the greatest possible ecosystem service improvement has been deliveredfortheresourcesdeployed. 10


Inthisreview,foreachoftheƤvemainpollutantcategories,wegiveanoverviewofthe interventions that can been delivered to mitigate the impacts of pollution on; (1) the ecological health of our river catchments, (2) the risks and costs incurred at drinking water treatment works through having to treat low quality raw water, and (3) on the generation of pollutionǦderived problems in the estuaries and coastal regions in the lowerreachesofrivercatchments. Furthermore,wealsodescribethecatchmentmanagementinterventionsconsideredto bethemosteơectiveinreducingdiơusepollutionandmitigatingtheimpactsdescribed. We will also attempt to evaluate and summarise the numerous studies (completed or currently underway) which allow us to estimate the scale of beneƤt that these catchmentmanagementinterventionscandeliveratavarietyofscales. In assessing and collating this evidence, we hope that we will be able to demonstrate with some certainty that signiƤcant improvements in water quality can be achieved through the targeted and integrated implementation of catchment management interventions. Thecatchmentmanagementinterventiontoolboxcanbedeliveredthroughavarietyof approaches,whicharedescribedinmoredetailinthesectionsbelow. Farmvisitsandadvice Anintegrated landmanagement advicepackagewillcovermanyaspectsofafarmers practiceandwillindicatewheretheadoptionofgoodorbestpracticemayminimisethe riskthatanactivitywillhaveanegativeimpactontheenvironmentandwhereitmay enhancetheprovisionofaparticularecosystemservice. Inadditiontobroadadviceongoodorbestpractice,anintegratedfarmadvicepackage should produce a targeted and tailored programme of measures that could be undertaken and should include speciƤc advice on pesticide, nutrient and soil managementonthefarmtomitigateanypotentialenvironmentalimpacts.

Illustrationshowingsomepracticesthatcanposeathreattowaterquality(leftside) andawidearrayofBestFarmingPractices(BFPs)(rightside)whichcanminimizeloss ofpollutantstowatercoursesasaresultofagriculturalactivity.

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CapitalgrantsforonǦfarminfrastructure Where an advisor believes it to be appropriate, they will recommend in the managementplanthatimprovementsoradditionsbemade totheinfrastructureona farm. Although some statutory designations, such as Nitrate Vulnerable Zones, do requirecertainstandardsinonǦfarminfrastructure,undermostschemestheuptakeof thesemeasuresisentirelyvoluntaryandtheadvisorwillindicatefundingmechanisms throughwhichagrantmaybeobtainedtocontributetothetotalcostofthework. Incentivisationtochangefarmingpractice Atpresent,farmers,whorepresentlessthan1%ofoursociety,currentlymanagenearly 80%ofourcountrysideandarelargelyresponsibleforthehealthoftheecosystemsit supports.However,despitetheirkeyroleinmanagingournaturalecosystems,farmers arecurrentlyonlypaidfortheprovisionofoneecosystemservice;foodproduction. DevonWildlifeTrust

To redress this apparent imbalance, there are now a number of funding programmes through which land managers and farmers can receive payments for adopting more environmentallybeneƤcialandecosystemservicesǦenhancingpracticesonallorpartof their land. Schemes of this type, in which the beneƤciaries of ecosystem services providepaymenttothestewardsofthoseservices,areoftenreferredtoasPayments forEcosystemServices(describedinmoredetailinAssessingImprovementsonp64). The basic idea behind Payments for Ecosystem Services is that those who are responsible for the provision of ecosystem services should be rewarded for doing so, representingamechanismtobringhistoricallyundervaluedservicesintotheeconomy. Farmingcommunityengagement&education Educationalandtrainingactivities,suchasfarmermeetingsandworkshops,whichraise awareness of diơerent initiatives and promote best practice among local farming communities,areakeycomponentofanycatchmentmanagementprogramme.They alsoservetoestablishrelationshipsandbuildtrustbetweenadvisorsandfarmersonthe groundinacatchment.

CDŽSE SƼǟLjY /ƩAF (/ʖɻʘʖng EʜvʖUʝʜȷʑnɢ Anɍ Fʋʢʛʖng) LEAF is the leading organisation promoting sustainable food and farming. They help farmers produce good food, with care and to high environmental standards, identiƤed inǦstore by the LEAF Marque logo. LEAF attempts to build public understanding of food and farming in a numberofways,including;Open Farm Sunday,Let Nature Feed Your Senses andyearround farmvisitstoournationalnetworkofDemonstrationFarms. LEAFisalsoanindustrypartnerintheCampaignfortheFarmedEnvironment(CFE),whichisan opportunityfortheirmemberstodemonstratetheircommitmenttoprotectingandenhancing thefarmedenvironment.AspartoftheCampaign,farmersareaskedtoensurethatathirdof their ELS points come from a list of key target options. These include options which result in cleanerwaterandhealthiersoil,protectfarmlandbirdsandencouragewildlifeandbiodiversity. LEAFalsoprovideawidearrayofeducationalandbestpracticeguidanceresources ontheirwebsite,includingtheirWater Management Tool,whichoơersfarmersa complete health check for water use on their farms, and the Simply Sustainable WaterGuidancebookletandƤlm.TheSimplySustainableWaterbooklethasbeen produced to help farmers develop an eơective onǦfarm management strategy for eƥcientwateruseandtoimprovetheirfarm’scontributiontoprotectingwaterin the environment.Itallowsfarmerstogetthebestfromthisvaluableresource,to improveawarenessoftheimportanceofwaterandtrackchangesinwateruseand qualityovertime. BasedonSixSimpleStepstohelpimprovetheperformance,healthandlongterm sustainability of their land, farmers are encouraged to set a baseline by assessing theirwateruseandtheirwatersources.Thesixkeymeasuresare:(1)watersaving measures, (2) protecting water sources, (3) soil management, (4) managing drainage,(5)trackingwateruse,and(6)wateravailabilityandsunshinehours. 12


'ɰʙʖɃʑʢɨ ȷeʃKoGɡ fʝɠ caWɭʕȷʑnɢ PʋnaȰʑȷʑnɢ At present there are a number of diơerent programmes and initiatives via which catchment management interventions are funded to deliver catchmentǦscale improvementsinwaterqualitythroughthedeliveryoflandmanagementadviceandonǦ farmmeasures. PerhapsthemostsigniƤcantoftheseare;theNaturalEnglandǦcoordinatedCatchment Sensitive Farming initiative, some elements of the Natural England Environmental Stewardship Scheme and a number of newly established water companyǦfunded schemes, such as the South West Water Upstream Thinking Initiative and the United UtilitiesSustainableCatchmentManagementProgramme(SCaMP). In addition to these programmes, the Environment Agency, Natural England, the Forestry Commission and a number of nonǦgovernmental organisations also make considerable investment of their resources in the delivery of advice and practical supportforpeoplemanagingnaturalresourcesinthecatchment. Eachofthesecatchmentmanagementprogrammeshavediơerentfundingmechanisms and use diơerent methods to target and deliver funding. For example, Catchment Sensitive Farming oơers smallǦmedium grants (up to £10,000 per farm) for capital investmentsinfarminfrastructureinitsprioritycatchmentsalongsideaprogrammeof advice and training. In contrast, Environmental Stewardship Schemes oơer revenue paymentsinreturnforthedeliveryofasuiteofonǦfarmmeasuresintheirtargetareas.

CDŽSE SƼǟLjY CaWɭʕȷʑnɢ SʑnʣiʤʖɃɏ Fʋʢʛʖng Funded by DEFRA and the Rural Development Programme for England, Catchment Sensitive Farming (CSF) is a joint initiative between the Environment Agency and Natural England that has beenestablishedinanumberofprioritycatchmentsacrossEngland. Overall, CSF has two principle aims: (1) to save farms money by introducing careful nutrient and pesticide planning, reducesoillossandhelpfarmersmeettheirstatutoryobligationssuchasNitrateVulnerableZones,and(2)todeliver environmentalbeneƤtssuchasreducingwaterpollution,cleanerdrinkingwater,saferbathingwater,healthierƤsheries, thrivingwildlifeandlowerƪoodriskforthewholecommunity. To achieve these goals CSF delivers practical solutions and targeted support which should enable farmers and land managerstotakevoluntaryactiontoreducediơusewaterpollutionfromagriculturetoprotectwaterbodiesandthe environment. CatchmentSensitive Farming Oƥcersworkwithindependentspecialistsfromthefarmingcommunitytodeliverfree advice tailored to the area and farming sector. This advice includes workshops, farm events and individual farm appraisals. CSF also oơer capital grants, at up to 60% of the total funding, to deliver improvements in farm infrastructure. As part of the Catchment Sensitive Farmingprogramme,NaturalEngland have also undertaken an evaluation study to demonstrate the beneƤts that the delivery of advice and measureshaverealised. In addition to a summary report (http://tinyurl.com/mzyrpc7), Natural Englandhavealsoproducedanumber of case studies and technical reports covering speciƤc areas; such as, advice and education delivery, water qualitymonitoringandenvironmental modelling. These can be accessed at http://tinyurl.com/pk5rulg.

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LikeCatchmentSensitiveFarming,theSouthWestWaterUpstreamThinkinginitiative also oơers capital grants for onǦfarm infrastructure improvements, but it also places conditions on the management of the new infrastructure and on other activities undertakenonthefarmfollowingtheinvestmentviaadeedofcovenant. Inaddition,theWestcountryRiversTrust,alongwithDEFRAandtheUniversityofEast Anglia, have recently investigated the potential of an innovative ‘reverse auction’ approach to target the allocation of funding in a catchment (see below). This work, undertakenontheRiverFoweyaspartoftheUpstreamThinkingProjectandaspartof aDEFRA Payments for Ecosystem Services (PES)Pilot Project hasdemonstratedthe costǦeơectiveness of this method for the distribution of catchment management funding.

CDŽSE SƼǟLjY 8pVʤreʋm Tʕʖɻʘʖng South West Water (SWW)incollaborationwithagroupofregional conservation charities, including the Westcountry Rivers Trust, the county Wildlife Trusts for Devon and Cornwall and The Farming and Wildlife Advisory Group, have established one of the largest andmostinnovativeconservationprojectsintheUK:the‘Upstream ThinkingInitiative’. This project will deliver over £9 million worth of strategic land restorationintheWestcountrybetween2010and2015. The‘providerispaid’fundingmechanismusedintheUpstreamThinkingschemeis,perhaps,themostinnovativeaspect oftheproject.SWWhaverecognizedthatitischeapertohelpfarmersdelivercleanerrawwater(waterinriversand streams)thanitisto pay forthe expensiveƤltrationequipment requiredtotreatpollutedwaterafter itis abstracted from the river for drinking. SWW believe that water consumers will be better served and in a more costǦeơective manneriftheyspendmoneyraisedfromwaterbillsoncatchmentrestorationintheshorttermratherthanonwater Ƥltrationinthelongterm.Theentire5yearinitiativewillcosteachwaterconsumerintheSouthWestaround65p. FoweyRiverImprovementAuction IntheƤrstschemeofthiskindintheUK,anauctionwassuccessfully usedtodistributefundsfromawatercompanytofarmers,investing incapitalitemstoimprovewaterquality.Theworkwassupportedby the Natural Environment Research Council Business Internship scheme,managedbytheEnvironmental Sustainability Knowledge TransferNetwork. The scheme oơered SWW the opportunity to work directly with researchers from the University of East Anglia to devise an innovative mechanism for paying for the delivery of ecosystem servicesviatheirUpstreamThinkingscheme. Upstream Thinking uses an advisorǦled approach in other areas. Advisors from the Westcountry Rivers Trust visit farms to suggest work and pay grants at a Ƥxed rate. The disadvantages of this approacharethatit’slabourintensive,notpracticaltovisitallfarms andthepotentialforallthefundstobeusedonasmallnumberof farms.Themainadvantageisthatadvisorscansuggestinvestments mostlikelytoimprovewaterquality. The University of East Anglia devised an auction approach, working with Westcountry Rivers Trust to: (1) increase coveragebyencouragingalleligiblefarmerstoparticipate,and(2)achievemaximumwaterqualitybeneƤtsatthesame timeasachievingeƥciencyforSWW’sinvestment.

 150farmersintheFoweycatchment,werecontactedinSummer2012withalistofcapitalinvestmentseligiblefor funding,plusadditionalfarmmanagementpracticeswhichcouldbeaddedtoincreasebidcompetitiveness.

 Farmerswereaskedtoentersealedbidsuptoamaximumof£50,000perfarm.  42bidswerereceived,requestingatotalof£776,000and18bidsmetthevalueformoneythreshold,withgrantrates paidintheschemefrom38%tothefull100%. 14


AVȿeVʣʖng ʃȱɏ eɑ£caʎɨ Է ʖntʑʢɃʑnʤiʝnɡ The principal, overǦarching aim of catchment management is to improve raw water quality in lakes, rivers and coastal waters. If eơective, this approach could make a signiƤcant contribution to their attainment of good ecological status, in accordance withtheEUWaterFrameworkDirective. In addition, it could also reverse the escalating risks and costs associated with the treatment of drinking water from our groundwater and surface water sources and it could reduce the impacts of pollution on our most sensitive and highly productive estuariesandcoastalenvironments. Given the potentially signiƤcant role of this approach in the improvement of water quality, it is vital for that we collect suƥcient evidence to provide an objective and scientiƤcallyrobustassessmentoftheeơectivenessoftheinterventionsused. Ultimately, we must be able to justify that the money spent and the interventions delivered across the landscape have delivered both signiƤcant improvements in water qualityandanumberofsecondaryƤnancial,ecologicalandsocialbeneƤts.

Determinewaterqualityimpacts

Identify&qualifypressures

Locatesources&pathways

Developprogrammeofmeasures

Fund&delivermeasures

Measureimprovements

R Inthisreviewwehaveattemptedtocollectacomprehensiveandrobustsetofdataand evidence,which,takentogether,demonstratesqualitativelyandquantitativelythatthe delivery of integrated catchment management interventions can deliver genuine improvementsinwaterquality. Insections2to6wehave,foreachofthemaingroupsofpollutants,identiƤedkey sourcesofpollutantloadsandexaminedtheimpactsthesepollutantshaveonthe aquaticenvironment,includinghowtheytranslateintoacostorrisktosociety.

RecordsecondarybeneƤts

Asummaryofthecyclicalandadaptive catchmentmanagementprocess:from thecharacterisationofimpactstothe identiƤcationofpressuresandonto thedeliveryofmeasuresandthe evaluationofimprovementsachieved.

We have also identiƤed key mitigation measures for reducing pollutant loads and evaluatedthedataandevidencefortheeƥcacyofthesemeasures.Thisprocesshas alsoallowedustoidentifytheinterventionsforwhichtheevidenceofeƥcacydoes notexistorwhereitdoesnotexistatanappropriatescale. Section 7 addresses issues of scale and reviews a selection of modelling tools that can be used to predict the impact of interventions and measures at a larger subǦ catchment or wholeǦcatchment scale. This section also explores the potential for secondaryenvironmental,economicandsocietalbeneƤtstoresultfromthedelivery ofcatchmentmanagementinterventions. Section 8 reviews the governance structures currently being used to implement a catchment managementǦbased approach in the UK and explores some of the approachesnowbeingadoptedtocreatecatchmentmanagementplans.

AssessingƤshpopulationsusingelectroƤshing

15


NUTRIENTS&ALGAE

ƴ8TƺINJNǝS & DŽǒGAE

16


NUTRIENTS&ALGAE

N8TƺINJNǝS & AǒGAE NitrogenǦandphosphorusǦcontainingcompounds(oftentermednutrients)are natural and vital components of healthy aquatic ecosystems. They play a critical role in supporting the growth of aquatic plants, which, in turn, produce oxygen and provide habitatsthatsupportthegrowthandreproductionofotheraquaticorganisms. NitrogenǦ and phosphorusǦcontaining nutrients also support the growth of algae, anothernaturalcomponentofmanyaquaticecosystems.Algaeoccurinthebenthicand planktonicphasesoffreshwaterhabitatsandformakeycomponentofthefoodchain formanyspeciesofƤsh,shellƤshandinvertebrateassemblages. Unfortunately, when nutrients are released into the environment, deliberately or accidentally,asaresultofhumanactivities,itcanresultinaperturbationoftheƤnely balancedequilibriumofnutrientscyclingthroughtheecosystem. When nutrients accumulate in aquatic ecosystems they drive the uncontrolled and unbalanced growth of aquatic plants and algae in a process called eutrophication and thesesoǦcalledplantoralgal‘blooms’canthencausesevereproblemsforotheraquatic organisms,theecologicalhealthofawaterbodyandforthehumanswhoalsodepend onthewaterfordrinkingwater,recreationaluseorfortheproductionoffoodsuchas ƤshandshellƤsh.

SʝuUȪeɡ Է ʜXʤʢȲʑnWɡ TherearethreeprincipalsourcesofnitrogenǦandphosphorusǦcontainingcompoundsin a river catchment: point anthropogenic sources, point agricultural sources and diơuse agriculturalsources.

 Point anthropogenic sources. A considerable fraction of the phosphorus in river water may be derived from inputs of sewage eƫuent (which may or may not have beentreated),fromdrainagesystemsinurbanareas,septictanksandfromroadside drains.Theprincipalsourcesofphosphatesandnitratesinsewagearehumanfaeces, urine, food waste, detergents and industrial eƫuent that have been discharged to the sewers. Typical sewage treatment processes generally remove 15Ǧ40% of the phosphorus compounds present in raw sewage and there are many small sewage treatment facilities and septic tanks in rural areas which could also be making signiƤcantcontributionstothephosphorusloadinriversandreservoirs.

 Point agricultural sources. Theseincludefarminfrastructuredesignedtostoreand

Therearenumerouspotentialsources ofnutrientsinrivercatchments; includingsewagedischarges(top), agriculturalpointsourcessuchasslurry stores(middle)anddiơusesourcessuch asfertiliserappliedtoagriculturalland (bottom).

manage animal waste and other materials such as animal food. Key infrastructure includes dung heaps, slurry pits, silage clampsand uncovered yards. Animal access pointstowatercoursescanalsoleadtothedirectdeliveryofphosphoruscompounds tothewaterandtotheirmobilisationfollowingchannelsubstratedisturbance.

 Diơuse agricultural sources. When large amounts of manure, slurry or chemical phosphorusǦcontaining fertiliser are applied to land, and this coincides with signiƤcant rainfall, it can lead to runǦoơ and the transfer of phosphorus into watercourses.Thisisaparticularproblemwhereheavysoilsarefarmedintensively, whichcanresultintheircompactionandanincreasedriskofsurfacerunǦoơ. There are a number of methods that can be used to estimate the level of nutrient enrichment in a watercourse and to determine where this contamination has been derived from. For example, it is widely accepted that a detailed evaluation of the benthic algae (diatom) communities in a river can provide a robust assessment of its ecological condition, because these diatom communities are particularly sensitive to changesinthepHandnutrientlevelsinthewater. In addition to biological assessments, water quality monitoring can also be used to characterisethelevelsofnutrientenrichmentinriversandidentifywhichsectionsofa catchmentarecontributingmosttothenutrientloadatanyparticularlocation. However,waterqualitysamplingcanbecostlyandtimeconsuming,whenundertaken atƤnetemporalorspatialscales,andmuchoftheworktoidentifysourcesofnutrient pollution in river catchments has therefore focused on the use of models such as the Extended Nutrient Export Coeƥcient Plus (UniversityofEastAnglia),thePhosphorus and Sediment Yield CHaracterisation In Catchments (PSYCHIC) model (ADAS Water Quality)andthenewSourceApportionmentGIS(SAGIS)tool(AtkinsUK).  17

RobertMarshall


NUTRIENTS&ALGAE

CDŽSE SƼǟLjY SʝuUȪɏ Aʠpɛԯiʝʜȷʑnɢ-GǏS (ƻDŽGǏS) Podɰɸʙʖng ʓUʋȷʑwʝʁk TheSourceApportionmentǦGIS(SAGIS)modellingframeworkwasdevelopedthroughUWKIRresearchprojectWW02: Chemical Source Apportionment under the WFD (UKWIR, 2012) with support from the Environment Agency. The primary objective of this research was to develop a common modelling framework as the basis for deriving robust estimatesofpollutionsourcecontributionsthatwouldbeusedtosupportbothwatercompanybusinessplansandthe EARiverBasinPlanningprocess. TheSAGIStoolquantiƤestheloadsofpollutantstosurfacewatersintheUKfrom12pointanddiơusesourcesincluding wastewater treatment works discharges, intermittent discharges from sewerage and runoơ, agriculture, soil erosion, minewaterdrainage,septictanksandindustrialinputs(UKWIRprojectWW02).Loadsareconvertedtoconcentrations using the SIMulation of CATchments (SIMCAT) water quality model, which is incorporated within SAGIS, so that the contributiontoinǦstreamconcentrationsfromindividualsourcescanbequantiƤed. Diơuse sources of nutrient pollution are incorporated into SAGIS from the Phosphorus and Sediment Yield CHaracterisation In Catchments (PSYCHIC) model (developed by a consortium of academic and government organisationsledbyADASWaterQuality). PSYCHICisaprocessǦbasedmodelofphosphorusandsuspendedsedimentmobilisationinlandrunoơandsubsequent delivery to watercourses. Modelled transfer pathways include release of desorbable soil phosphorus, detachment of suspendedsolidsandassociatedparticulatephosphorus,incidentallossesfrommanureandfertiliserapplications,losses fromhardstandings,thetransportofalltheabovetowatercoursesinunderǦdrainage(wherepresent)andviasurface pathways,andlossesofdissolvedphosphorusfrompointsources. ThemapsbelowshowthebaselineexportoftotalphosphorusfrommanureǦbasedsourcesacrosstheTamarcatchment predicted by the PYCHIC model (inset) and the modelled concentrations of Soluble Reactive Phosphate in subǦ catchmentsoftheTamarandtheirsourcesaccordingtotheSAGISmodellingtool(main).

18


NUTRIENTS&ALGAE

IʛpacWɡ Է ʜXʤʢȲʑnWɡ Onthehealthofaquaticecosystems The principal eơect of accelerated plant growth and algal blooms is the reduction (hypoxia)orelimination(anoxia)ofoxygeninthewaterasoxygenǦconsumingbacteria decomposetheplantsandalgaewhentheydieback.Thisreductionintheoxygenation of a waterbody can have a severe eơect on the normal functioning of the ecosystem, causing a variety of problems such as a lack of oxygen needed for Ƥsh, shellƤsh and invertebratestosurvive. Under the Water Framework Directive (WFD) classiƤcation scheme the ecological impactsofnutrientsonfreshwatersystemsarerecordedthroughthechangesthatthey exert on the plant and algal communities that are found in them. Changes in the composition of these communities are interpreted as an indication that nutrient enrichmentisperturbingtheecologicalhealthoftheecosysteminthatwaterbody. The impact of nutrients on the health of estuaries and coastal areas is still relatively poorly understood but, as with freshwaters, excessive nutrient loads can cause their eutrophication. The susceptibility of estuaries to nutrient enrichment depends on factorssuchasthephysicalcharacteristics,thehydroǦdynamicregimeandthebiological processesthatareuniquetoeachindividualestuary.Generallyspeaking,estuariesand coastal areas are thought to be less susceptible to eutrophication due to their tidal nature, which results in high turbidity (less light penetration) and frequent ƪushing. Estuarieswithgoodlightregimesareoftenmoresensitivetonutrientenrichment.

Waterstarworts(Callitrichespp)(top) arejustonegroupofmacrophyte plantsthatcancauseproblemswhen theyproliferateexcessively.PhytoǦ benthicalgae(diatoms)areparticularly sensitivetonutrientenrichment (bottom).

Primary producers in estuaries may be opportunistic green algae, epiphytes or phytoplanktonandexcessivegrowthofanyorallofthesecanimpactonwaterturbidity andlightavailability,causingchangesinthedepthdistributionsofplantcommunitiesin thewatercolumn.Suchchangescanhaveimplicationsforthestructureandfunctioning of estuarine and coastal food webs, with potential consequences for Ƥsh and shellƤsh Ƥsheriesandforbathingwaterqualityonneighbouringbeaches. In addition to the assessment of these biological indicators, the levels of Soluble ReactivePhosphorus(SRP)inwaterbodiesarealsomeasuredand,throughcomparison with established thresholds known to cause ecological impacts, the levels are used to identify where degradation might be expected to occur. The WFD threshold above which SRP is expected to have a signiƤcant impact on the ecological condition of an aquatic ecosystem varies between diơerent waterbody types, but an average SRP concentrationabove50ug/lwouldresultinaWFDfailureinanywaterbodytype.

BobBlaylock

TheExeEstuaryatTopsham

19


NUTRIENTS&ALGAE

Ontheprovisionofdrinkingwater In addition tothe ecologicalimpactsofnutrient enrichmentleading to hypoxiaand/or anoxiainaquaticecosystems,algalbloomscanalsoresultinothernegativeeơectsthat havesigniƤcantconsequencesforthetreatmentandsupplyofdrinkingwater. These include their potential to damage property or water supply infrastructure, to increasealgaeǦderivedtoxinsinthewaterandtocausetasteandodourproblems,allof whichcanresultinincreaseddrinkingwatertreatmentcosts. These impacts are particularly felt as blooms of algae and explosions of macrophyte growth begin to dieǦback at the end of the summer growing season or following the depletion of nutrients and oxygen in the water column, when a number of soǦcalled decompositionbiǦproductscanbereleased. ThethreeprincipaltypesofchemicalpollutantsproducedasdecompositionbiǦproducts of this type are: (1) ammonia/ammonium (NH4), (2) soluble organic compounds (e.g. methylǦisoborneol(MIB)andgeosmin)and(3)dissolvedmetalions(e.g.manganese). Ammonia and its ionised cationic form ammonium (NH4+) are naturally occurring components of the nitrogen cycle that are generated in aquatic ecosystems by heterotrophic bacteria as the primary nitrogenous endǦproduct of organic material decomposition. In healthy aquatic ecosystems ammoniacal nitrogen is readily assimilatedbyplantsorconvertedthroughnitriƤcationtonitrate,butineutrophiclakes, where elevated levels of nutrients are driving algal blooms and the development of stratiƤed hypoxic conditions, this process can be inhibited and ammoniacal nitrogen thenaccumulatesrapidly. The presence of ammoniacal nitrogen in water can begin to have a toxic eơect on aquaticorganisms(especiallyƤsh)atconcentrationsabove0.2mg/l.Inaddition,when abstracted for drinking water treatment, ammoniacal nitrogen concentrations above 0.2 mg/l can also cause taste and odour problems as well as decreased disinfection eƥciencyduringchlorination.

Summaryoftheannualcostsassociated withfreshwatereutrophicationinthe UK.Costswerecalculatedas’damage costs’–i.e.thereducedvalueofclean ornonǦnutrientǦenrichedwater (adaptedfromPrettyetal.,2002).

The increased chlorination required to remove ammoniacal nitrogen during the treatment process can also lead to the indirect generation of dangerous chemical biǦ products such as trihalomethanes (THMs), which are thought to have toxic and/or carcinogenicpropertiesandareverydiƥculttoremovefromtheƤnaltreateddrinking water.Furthermore,increasesinthenitriƤcationofammoniaintherawwater,andthe increasedconsumptionofoxygenthatthisentails,mayalsointerferewiththeremoval ofmanganesebyoxidationontheƤlters,whichcanresultintheproductionofmouldy, earthyǦtastingwater. In2002theEnvironmentAgencycommissionedtheUniversityofEssextoundertakean assessmentoftheenvironmentalcostsresultingfromtheeutrophicationoffreshwater ecosystems in England and Wales. Their Ƥndings, summarised in the table below, revealedthatthetotaldamagecostswereintherangeof£75to£114million.

Costcategories

Rangeofannualcosts (£million)

Socialdamagecosts



Reducedvalueofwatersidedwellings

Healthcoststohumans,livestockandpets

£9.83 £0.50Ǧ1.00 £19.00 £20.10 £0.50Ǧ1.00 £5.12Ǧ7.99 £9.65Ǧ33.54 £2.94Ǧ11.66 £0.029Ǧ0.118 unknown

Reducedvalueofwaterbodiesforcommercialuse(abstraction,navigation,livestock,irrigationandindustry) Drinkingwatertreatmentcosts(treatmentandactiontoremovealgaltoxinsandalgaldecompositionproducts) Drinkingwatertreatmentcosts(toremovenitrogen) CleanǦupcostsofwaterways(dredging,weedǦcutting) ReducedvalueofnonǦpollutedatmosphere(viagreenhouseandacidifyinggasemissions) Reducedrecreationalandamenityvalueofwaterbodiesforwatersports,angling,andgeneralamenity Revenuelossesforformaltouristindustry Revenuelossesforcommercialaquaculture,Ƥsheries,andshellƤsheries

Ecologicaldamagecosts



Negativeecologicaleơectsonbiota(arisingfromchangednutrients,pH,oxygen),resultinginchangedspeciescomposition (biodiversity)andlossofkeyorsensitivespecies

£7.34Ǧ10.12

TOTAL

£75.0Ǧ114.3

20


There are a wide range of mitigation measures available for reducing nutrient inputs intotheaquaticenvironment. Soil,landandslurrymanagement Limiting fertiliser and manure inputs to suit crop requirements prevents overǦuse and reducesthequantitiesofsurplusnutrientsenteringthesystem.Mitigationmeasuresto limitnitrogeninputstosuitcroprequirementshavebeenshowntosubstantiallyreduce nitratelossesfromsoil(LordandMitchell,1998),butthesemethodsarelesseơectivein reducingphosphorousconcentrationsinrunǦoơduetophosphorousbuildǦupinsoil.

TheWestcountryRiversTrusthave producedaseriesoffarmǦmeasurefactǦ sheets,whichcanbefoundonthe DEFRAwebsiteat—http://tinyurl.com/ kqpyctv. 

Mitigationmeasurestoreducenutrientloadsthroughchangesinagriculturalland and soil management practices include the use of fertiliser placement technologies and avoiding application of fertiliser to highǦrisk areas. There are also a variety of conservation tillage techniques that can be implemented, with the aim of reducing nutrientlossesviasurfacerunǦoơ. Mitigation measures for improved soil, land and slurry management are listed below andtheevidencefortheireƥcacyissummarisedinthetablebelow:

 Implementationofconservationtillagetechniques  Fertiliserspreadercalibration  Useofafertiliserrecommendationsystem  Useoffertiliserplacementtechnologies  ReǦsitegatewaysawayfromhighǦriskareas  DonotapplyfertilisertohighǦriskareas  AvoidspreadingfertilisertoƤeldsathighrisktimes  DonotapplyPfertilisertohighPindexsoils  Installcoversonslurrystores  Increasethecapacityoffarmmanurestorage  Minimisevolumeofdirtywaterandslurryproduced  Changefromslurrytosolidmanurehandlingsystem

Thetablebelowsummariseskey Ƥndingsofresearchintotheeƥcacyof mitigationmeasuresaimedatlimiting nutrientlossesbychangingagricultural landandsoilmanagementpractices. TheseƤndingsarearesultofresearch carriedoutateitheraplotǦorƤeldǦ scale.

 Reference

MitigationMeasure

Findings

Benhametal.(2007)

Implementationofconservationtillage techniques

MeanlossesinsurfacerunǦoơfor

Daveredeetal.(2004)

Injectionofslurry

93%reductionindissolvedreactivePinrunǦoơ 82%reductionintotalPinrunǦoơ 94%reductioninalgalǦavailablePinrunǦoơ

Deasyetal.(2010)

Tramlinemanagement

Tramlinemanagementreducednutrientandsediment lossesby72Ǧ99%on4out5sitesandwereamajor pathwayfornutrienttransferfromarablehillǦslopes

Gossetal.(1988)

Directdrilling

Winterlossesofnitrogenwasonaverage24%lessthan forlandthathadbeenploughed

JohnsonandSmith(1996)

Shallowcultivation(insteadofploughing)

Decreasednitrogenleachingby44kgperhectareover a5yearperiod

Poteetal.(2003)

Incorporationofpoultrylitterinsoil

80Ǧ90%reductioninnutrientlossesfromsoil

Poteetal.(2006)

Incorporationofinorganicfertilisersinto soil

Reductionofnutrientlossestothewaterenvironment tobackgroundlevels

Shephardetal.(1993,1996and 1999),Gossetal.(1998),Lordet al.(1999)

Plantingagreencovercrop

50%reductioninnitratelossescomparedtowinterǦ sowncereal.Uptakeofnitrogenrangingbetween10 and150kgperhectare

Withersetal.(2006)

Ensuretramlinesfollowcontoursoftheland acrosstheslope

NosigniƤcantdiơerencesinrunǦoơquantity,sediment andtotalphosphorousloadscomparedtoareaswithno tramlines

Zeimenetal.(2006)

Ensuringaroughsoilsurfacebyploughing ordiscing

TransportofsolublephosphorusinsurfacerunǦoơ reducedbyafactorof2Ǧ3comparedtountilledsoils

21

 totalnitrogenwasreducedby63%  ammoniawasreducedby46%  nitratewasreducedby49%  totalphosphoruswasreducedby73%

NUTRIENTS&ALGAE

MiʤiJaʤiʝɚ ȷeaʣureɡ & ʃȱʑʖɠ eɑ£caʎɨ


NUTRIENTS&ALGAE

CDŽSE SƼǟLjY RʖɃʑɠ 2Խʑɠ CaWɭʕȷʑnɢ MʋnaȰʑȷʑnɢ PUʝjecɢ The River Otter rises in the Blackdown Hills in East Devon and runs for approximately 25 miles southwest to the sea. BelowHoniton,theOtterentersitsƪoodplainandrunssouththroughseveraltownsandvillagesbeforereachingthesalt marshesatBudleighSalterton.Initslowerreaches,theOtterbecomesagravelǦbedriverthatmeandersthroughrolling topographywithmixedagriculturallanduse,includinglivestock,cereals,oilseeds,fruitandvegetables. Issues DuetothesandynatureofthesoilsintheOttercatchment,leachingofnitrateandpesticidesiscommon.SouthWest Water (SWW) relies heavily on the lower Otter boreholes to meet local drinking water demands and many of these boreholeshaveshownworryingtrendsinnitratelevels.Sedimentandphosphatelevelsinsurfacewatersarealsohigh andinneedofattention. High nitrate levels increase the burden of supplying potable water and, although the SWW Dotton treatment plant is capable of blending and stripping excess nitrate from the extracted water, its capacity is limited. Reducing the nitrate contentinrawwaterwillreducedthisburdenanditsassociatedeconomicandenvironmentalcosts. DeliveryofInterventions Farm visits were made to engage with farmers and explain the beneƤts of better nutrientmanagement.Whereappropriate,farmerswereprovidedwithfarmreportsto highlight priority areas likely to inƪuence raw water quality and to provide advice on managementpracticestoreduce pollutant loads. From2010Ǧ2012,thirtyǦsevenfarms werevisitedandeightreceivedfarmreports.Eventswerealsoheldtoengagewiththe farmingcommunitywhilstatthesametimetobolstertheunderstandingoftheproject aims. Events have included fertiliser spreader workshops, crop trial workshops and visitstotheSWWwatertreatmentworks. Following the visit to the water treatment works one farmer commented that the project was, “...veryinteresting.OurstrategyhasmoreinƪuenceonwaterqualitythanI thought...”. Monitoring&Outcomes Focusingonthenitratecontributionfromagriculture,amonitoringstudywassetuptoassesstherelativecontributions fromdiơerentlandusetypeswithinthecatchmentandtomonitorchangesinnitratelevelsfollowingfarmvisits. TengeographicallydiversefarmerskindlygavepermissiontouseasingleƤeldoneachoftheirfarmsfortesting,preǦand postǦwinter.Eachfarmwaschosencarefullytoensurearepresentativeselectionoflandusetypeswereincluded. Thenitratetestingsiteswereselectedin2010andsamplingwasundertakeninNovember2010,MarchandNovember 2011,MarchandNovember2012andMarch2013.ThediơerenceinnitratelevelsrecordedinthesoilbetweenNovember andMarchgivesavaluefornitrogenlostoverwinter. The chart (left) shows that overall levels of nitrogen lost from the soil has decreased signiƤcantly over the monitoringperiod,withlevelsin2012/2013approximately athirdofthelevellostoverthe2010/2011winter. Theamountofnitrogenusedbythecurrentcrophasbeen takenintoaccount,whereappropriate,andtheremaining fraction of nitrogen unaccounted for is considered to be associated with the export of animal products, crops, leaching, deǦnitriƤcation and volatilisation. In most cases, the nitrogen loss will mainly be associated with leaching, volatilisation and deǦnitriƤcation, all of which are environmentallydamaging. Whiletheseresultsareencouraging,thereareseveralotherfactorsthatcouldhavecontributedtothisreduction,suchas theweather,anditisnotpossibletoprovethatthesepositiveresultsaredirectlylinkedtointerventions.However,they dooơerasnapshotoftheproblemsfacedinthisareaandcertainlypointtowardsapositiveimpactresultingfromthe provisionofnutrientadviceonfarmvisitsandinfarmplans. Thismonitoringworkalsoprovidesinvaluabledataforthefarmersparticipatingintheprojectandhelpstoreinforcethe projectaims,asdemonstratedbypositivefarmerfeedback.

22


SourcesofphosphorusintheEU

Mitigationmeasuresdesignedtoreducenutrientsinputsfromlivestockarelistedbelow andtheevidencefortheireƥcacyissummarisedinthetablebelow:

 Reductioninstockingdensity  ReductionindietaryNandPintakes  Exclusionoflivestockfromwaterbodiesandprovisionofalternativedrinking sources

 Exclusionoflivestockfrompoorlydrainedareasoflandtopreventpoachingand subsequentmobilisationofsoilsandnutrients Reference

MitigationMeasure

Findings

HeathwaiteandJohnes (1996)

Reducedlivestockgrazingdensity

PhosphorousexportsinsurfacerunǦoơwasrecordedas:

Hugingetal.(1995)

Reducelivestockgrazingdensity

x 2mgtotalPperm2forungrazedland x 7.5mgtotalPperm2forlightlygrazedland x 291mgtotalPperm2forheavilygrazedland ThereisasigniƤcantrelationshipbetweengrazingintensity andnitrogenlossestowater Nitrogenleachinglosseswerereducedby69%

Kurzetal.(2006)

Exclusionoflivestockfrompoorlydrained areasoflandtopreventpoaching

Line(2003)

FencingthewatercoursetoexcludeliveǦ stockcombinedwitha10Ǧ15mbuơerǦstrip

Totalphosphorousloaddecreasedby76%

FencingthewatercoursetoexcludeliveǦ stock

Streamswithinfencedoơareasshowedrapidimprovement invisualwaterclarityandchannelstability

Parkynetal.(2003)

Decreasedconcentrationsoftotalnitrogen,organicphosǦ phorousandpotassiumweremeasuredinsurfacerunǦoơ fromunǦgrazedareaswhencomparedtograzedareas Totalorganicnitrogenloaddecreasedby33%

Solublereactivephosphorousdecreasedbyupto33%in somestreams,althoughinothersitincreased Totalnitrogendecreasedbyupto40%insomestreamsbut increasedinothers Sheƥeldetal.(1997)

Provisionofalternativedrinkingsourcefor livestock

Totalphosphorusloaddecreasedby54% Totalnitrogenloaddecreasedby81%

CDŽSE SƼǟLjY E[ɭʙXʣiʝɚ Է ʙʖɃeVWoɭk ʓUʝm poʝʁʙɨ ʏUʋʖȸeɍ ʋreaɡ Է Oʋnɍ Wɛ ʠrʑɃʑnɢ poaɭʕʖng Poaching aroundfeedingand drinkingareascan leadtosoildamage, aswellasstockwelfareandpollutionproblems, particularlyduringwetperiods.SimplemanagementchangescanhelpfarmerstobeneƤtfrom:

improvedstockhealthandlowervetbills reducedsoildamage,erosion,runoơandwatercoursepollution improvedgrassproductionandnutritionalvalue reducedswardrestorationcosts. reducedriskofdamagetoenvironmentallysensitiveareas CarefulmanagementofoutǦwinteredstockandequipmentinordertoavoidserious damagetosoilsandswardwasundertakenon5haofgrassland.Regularinspections, particularlyinwetweatherallowedmovementtobetterǦdrainedareasbeforeserious poachingoccurred. This resulted in 10% less grass to be restored, encouraged early recovery and provided an early spring “bite”. Annual savings included 10% less grass to be reseeded @ £54/ha and 10% less loss of forage@ £24/ha. The total saving for 5ha was£390withanimmediatepayback. 23

NUTRIENTS&ALGAE

Managementoflivestock IntheirEuropeǦwidestudyintothesourcesofphosphorusinputsintorivers,Morseetal (1993) estimated that the most signiƤcant contributions were from livestock, human wasteandfertiliserrunǦoơsources(seechartright).


NUTRIENTS&ALGAE

CDŽSE SƼǟLjY BɤՔʑɠ Sʤʢʖpɡ fʝɠ ʜXʤʢȲʑnɢ pɼɸʙXʤiʝɚ ʛiʤiJaʤiʝɚ Creation of riparian buơer strips along watercourses is perhaps the most widely recommended mitigation method for controllingdiơusepollutionlossesfromagriculture.Consequently,researchintotheeƥcacyofbuơerstripsinreducing pollutantloadenteringwatercourseshasbeenextensive. A riparian buơer strip can be deƤned as a corridor of natural vegetation betweenagriculturallandandawatercourse.Theyactasbarrierstosurface ƪows and therefore impact on delivery of pollutants to watercourses. The rate of surface runǦoơ is slowed as the water meets resistance from vegetationandƪowsoverrougherandmoreporoussurfacematerial. Thesubstantialrootsystemsbeneaththesurfacealsoincreasethelikelihood ofinƤltration.Slowerƪowingwaterhasareducedcapacityforthetransport of particulate matter and, as a result, there is increased deposition of sedimentpriortosurfaceƪowsreachingthewatercourse. Therearenumerousfactorsthatmayinƪuencetheperformanceofbuơerstripsinreducingpollutantload.Theseinclude thecharacteristicsoftheincomingpollutants,thetopographyandsoilsofthelandsurroundingthewatercourseandthe characteristics of the buơer strip itself, for example vegetation type and width. In addition, seasonal variations in meteorologicalconditionsandfarmingpracticescanalsoinƪuencebuơerstripperformance. TheƤndingsofthemanystudiesintotheeƥcacyofbuơerstripinmitigatingnutrientlossesfromfarmlandareshownin the table below. These results illustrate the variability inherent in quantifying the eƥcacy of buơer strips in reducing nutrient inputs to watercourses, with the range of eƥcacy for total phosphorus varying from 30 to 95% and for total nitrogen,from10to100%.  Reference AbuǦZraigetal.(2003)

Eƥcacy(%reduction) Location

BuơerWidth(m)

SoilTexture

Slope(%)

Phosphorous

Nitrogen

Canada

2

Siltloam

2.3

57Ǧ64







5





47Ǧ60







10



5

65Ǧ72







15



2.3

55Ǧ93



BarƤeldetal.(1998)

USA

4.6



9



92





9.1







100





13.7







97

Barkeretal.(1984)



79







99

BlancoǦCanquietal. (2004)

USA

0.7

Siltloam

4.9

44Ǧ63

62Ǧ77









54Ǧ72

35Ǧ36













22Ǧ53





4



77Ǧ82

82Ǧ83









81Ǧ91

54Ǧ70







  





71Ǧ84





8





87Ǧ91

88Ǧ90











96Ǧ99

83Ǧ84













87Ǧ95

Borinetal.(2004)

Italy

6

Sandyloam

3

78

72

Coleetal.(1994)



2.4Ǧ4.9

Siltloam

6

93



UK

4.6

Siltloam

11Ǧ16

73

27











49







9.1





93

57











56



UK

1.5

Siltloam

10

8

57









62

68

Dillahaetal.(1988)

Doyleetal.(1977) 

Continuedoverpage...

24


 Reference

Eƥcacy(%reduction) Location

BuơerWidth(m)

SoilTexture

Slope(%)

Phosphorous

Nitrogen

Duchemin&Madjoub



3

Sandyloam

2

85

96

(2004)









41







9





87

85











57



Edwardsetal.(1983)

UK

30

Ǧ

2

47Ǧ49



Knauer&Mander(89)

Germany

10

Ǧ



70Ǧ80

50

Kronvangetal.(2000)

Denmark

0.5

Sandyloam

7

32





29





100



Norway

5

Siltloam

12Ǧ14

46Ǧ78







10





80Ǧ90



Leeetal.(2000)



7.1

Siltyclayloam

5

28Ǧ72

41Ǧ64

Limetal.(1998)

USA

6.1

Siltloam

3

74.5

78











76.1







12.2





87.2

89.5











90.1







18.3





93.0

95.3











93.6



Magetteetal.(1987)

UK

9.2

Sandyloam



41

17

McKergowetal.(03)

Australia



Loamyland

<2

6

23

Muenzetal.(2006)

USA

25

Sandyclayloam

16.5

50

50

France

6

Siltloam

7Ǧ15

22

47



18





89

100

Parsonsetal.(1991)

USA

4.3Ǧ5.3

Ǧ



26

50

Schmittetal.(1999)



7.5

SiltyclayǦloam

6

48

35











19







15





79

51











50



Schwer&Clausen (1989)



26

Sandyloam

2

89

92









92



NewZealand

10

Ǧ



55

67









80



Norway

5

Ǧ



65Ǧ85

40Ǧ50



10





95

75

UK

12

Ǧ

4

44





36





70



Sweden

5

Ǧ



40Ǧ45

10Ǧ15





10





65Ǧ70

25Ǧ30





15





85Ǧ90

40Ǧ45

UK

27

Ǧ

4

76Ǧ96

82Ǧ94



91

Siltloam





38

 Kronvangetal.(2004)

Pattyetal.(1997) 

Smith(1989)  Syversen(1992)  Thompsonetal. (1978) Voughtetal.(1995)

Youngetal.(1980) Zirschkyetal.(1989)

25

NUTRIENTS&ALGAE

BuơerStripsfornutrientpollutionmitigation...continued….


NUTRIENTS&ALGAE

CDŽSE SƼǟLjY Mɵɸl Crȭɰk, PʑʜnʣʉʙYʋʜiɈ SWatɏ, ǟƻA The Mill Creek catchment drains into the Stephen Foster Lake in the northern mountain region of Bradford County, Pennsylvania,USA.Whilegreaterthanhalfofthesurrounding26km2catchmentareaisusedforagriculturalproduction, theremainderispredominantlyforested. OvertimeMillCreekhasdepositedexcesssedimentandnutrientrunǦoơintothe28Halake.Asaresult,Pennsylvania added Stephen Foster Lake to the state’s list of impaired waters in 1996 for nutrient and sediment runoơ due to agriculturalactivities.Subsequently,aTotalMaximumDailyLoad(TMDL)forthelakethatcalledforreductionsof49% forphosphoruswasestablished.

Catchmentmanagementplan SeveralcomputermodelswereusedtoestimatetheloadreductionsthatmightresultfromBestManagementPractices (BMPs)beingimplemented.Withthecombinationoftheseeơorts,thenutrientrunoơwasestimatedtobereducedby 52%andsedimentrunoơreducedby59%,exceedingthereductionrecommendedintheTMDL. The suggested BMPs were primarily aimed at the control of nutrient inputs from animal wastes, which contribute an estimated175kgofphosphorus(10%ofthetotalannualload).Erosioncontrol,tofurtherreducenutrientandsediment loadingstothelake,areestimatedtoreducethetotalphosphorusloadinitbyanadditional10%. Deliveryofinterventions AllthirteenfarmsintheMillCreekcatchmentwerepaidtoimplementagriculturalBMPsunderacontractthatcallsfor10 yearmaintenanceofthepracticesinreturnforthetechnicalandƤnancialassistance.Additionallytwodeedrestrictions wereappliedtotwobarns. Upstream of the lake, farmers and the Bradford County Conservation District installed 9 miles of stream fencing and alternative water supply systems to help prevent cattle from wandering intowaterways. Agricultural crossings, to swiftly move cattle across streams and prevent the animals from grazing near waterways and destroying riverbankswerealsoconstructed.

Manureandrunoơfromapreviouslyseverelydegradedmanurehandlingareaisnow containedanddirectedtothenewmanurestoragefacilityforƤeldapplication.

Farmfeedlotbeforeandafterinfrastructureimprovements.

Projectpartnersalsobuilt11systemstostoreand treat animal waste, planted riparian buơers, and restored 2,500 feet of stream channel. The Bradford County Conservation District identiƤed over $518,000 worth of improvements to be deliveredoverthe11farms. Monitoring&Outcomes PennsylvaniaDepartmentforEnvironmentalProtectionconducted biological monitoring and analysis of Mill Creek. Across the catchment there were four sample stations collecting monthly readings for pH, conductivity, a suite of Phosphate and Nitrogen measurements,alkalinity,totalsuspendedsolidsandtemperature.

GrowingSeasonTotalPhosphate(TP)loads(kg)enteringStephen FosterLakebefore(1994Ǧ95)andafter(2004,2005,2006&2008Ǧ09) deliveryofBestManagementPractices

Since2004thegrowingseasonTotalPhosphate(TP)loadentering StephenFosterLakedeclinedby50to90%relativetotheoriginal Phase I study (1994Ǧ95) load. As a result of these reductions, the lake has been in compliance with its total phosphorus TMDL targeted,growingseasonloadsince2005. 26


8ʠȼʑɠ TʋPʋɠ /ɪȴeɡ Fʋʢm IntʑʢɃʑnʤiʝɚ AVȿeVʣȷʑnɢ ThefarmislocatedintheTamarLakesCatchmentandhasaƤrstorderstreamwhichrunsnexttotheyard.The98Haof landiscomprisedofgentlyundulatingpasture(60Ha),arable(10Hainmaizeand20Hainwinterandspringbarley)and woodland.Themainfarmenterpriseisadairywith130milkersand50followers.Therearearound60bullcalvesandthe farmerhaswintersheepkeptoverOctobertoFebruary.Thedairyherdarehousedoverthewintermonths(September toMarch)andthefarmhasapproximately4monthsslurrystoragecapacity.Slurriesareseparatedintoaslurrylagoon andthreedirtywaterpits.Theslurryisspreadoverthelandbythefarmerusingthefarm’sownmachinery. Intervention Although the farmer demonstrated several good practices, there was a problem with his slurry store, which was outdated, could not cope with the demands of the modern dairy and did not aơord the environment with enough protectionagainstleaksandoverƪowingepisodes.Inthisinstancethe‘weepingwall’slurrylagoonwasplacedtooclose towatercourseandthereforerantheriskofpollutingit. In this situation the solution was to create a solid walled lagoon, which being slightly larger, allowed for slurry to be removedandspreadatappropriatetimes,aswellasgivingprotectiontothewatercourse.Thephotographsbelowshow theformalisationoftheslurrypitfromaninadequateweepingwallsystemtoaconcrete,bundedsysteminearly2008.

Monitoring Monitoring of aquatic invertebrates was undertaken and taxa scored against the BMWP scoring system (Biological MonitoringWorkingPartyǦNationalWaterCouncil,1981)toassesschangesinagriculturalpollution.Datawascollected overthetermoftheprojectfrom2007to2009andfurthermonitoringwasundertakenin2012toassessthelongǦterm eơects.Twositesoneupstreamandonedownstream(separatedbyaround100m)allowedassessmentoftheimpactof theintervention. Results The results of the BMWP scores show that there is a signiƤcant negative impact on water quality between the upstream score (blue line) and the downstream score (red line) in the Ƥrst two samples before the intervention.AftertheinterventioninEarly2008(green line) the diơerence between the upstream and downstream reduces suggesting that there is little waterqualitydiơerencebetweensites. Althoughthe2012upstreamanddownstreamreadings arelowerthanthe2008and2009readingsthereisstill littlediơerencebetweenthetwosuggestingthatthere continues to be no impact from the site in terms of waterquality.

BMWPscoresupstream(blue)anddownstream(red)ofafarmyardwithan inadequateslurrypitwithweepingwall.Theslurrypitwasupdatedinearly 2008(shownasangreenline)afterwhichthediơerencebetweenthetwo scoresreduces.Whilst2012Ƥguresarereducedcomparedto2008&2009the diơerencebetweenupstreamanddownstreamislessthanbeforeintervention.

Monitoring TheriverisasmallƤrstorderstream,whichgoespartwaytoexplainingtherelativelylowBMWPscoreswhencompared to second and third order streams in the area. It is highly likely that weeping wall slurry pit was having a signiƤcant negativeimpactondownstreamwaterqualityandtheinterventionofformalisingthepitreducedthediơerencebetween the two survey sites, both immediately after the intervention and four years later. The decrease in upstream and downstreamscoresin2012islikelytobewiderenvironmentalfactorssuchasanincreasesummerrainfall. 27

NUTRIENTS&ALGAE

CDŽSE SƼǟLjY


SUSPENDEDSOLIDS &TURBIDITY

ƻǟǜPNJǕ'NJ' ƻOLǏLjS & Ƽ8ƺƥǏDIǝ Y

28


SǟǜPNJǕ'NJ'

ƻOLǏLjS

&

Ƽ8ƺƥǏDIǝ Y

Therearemanyfactorsthatcancausetheturbidityofwatertoincrease,butthemost common are the presence in the water column of algae, bacteria, organic waste materials (including animal waste and decomposing vegetation) or silt (soil or mineral sediments).Thesematerialsareoftenreleasedintothewaterfollowingdisturbanceof theriverorlakesubstrate,buttheycanalsoenterthewaterasaresultoferosionand runǦoơfromtheland.

SʝuUȪeɡ Է ʣXʣȼʑndeɍ VɼʙiGɡ Numerous methods have been developed to identify the sources of suspended solids andthedynamicsofsedimenttransportinrivers.Thesemethods,whichvarygreatlyin thespatialscalesatwhichtheycanbeapplied,include:

 Fine sediment risk modelling. Uses topographic, rainfall and landǦuse data to identify areaswhere a highpropensityfor thelateral ƪowofwater over theland is likelytomobiliseƤnesedimentandtransportittotheriver.

 Sedimentloadsampling.Watersamplingtodeterminesuspendedsolidloadandthe contributionbeingmadebydiơerentsubǦcatchments.

 Sediment river walkover surveys. Rapid river surveys typically undertaken in wet weathertoidentifysourcesofsedimentandorganicmaterialenteringtheriver.

 Sourceapportionmentusingƪuorescent,chemicalandgeneticsignatures. Pioneeredbyresearchorganisations,suchasADASWaterQualityandtheUniversity of Plymouth, these approaches allow the areas of river bank or land that are contributingtotheinǦchannelsedimentloadtobeidentiƤed. Overall these studies reveal that the sediment load in rivers is derived from point or diơusesourcesinthreeprincipallocations:

 Materialfromtheriverchannelandbanks  Soilandotherorganicmaterialwashedoơfromthesurfaceofsurroundingland  Particulate material from anthropogenic sources; including point sources, roads, industryandurbanareas.

29

Examplesofsedimentbeingmobilised fromthelandsurface(inthiscasea countryroad;top)andenteringa watercourse(bottom).

SUSPENDEDSOLIDS &TURBIDITY

Turbidity isameasureofhowmuchsuspendedmaterialthereisinwater.Turbidityis reported in nephelometric units (NTUs), which are measured by an instrument (turbidimeterornephelometer)thatestimatesthescatteringoflightbythesuspended particulatematerial.


CDŽSE SƼǟLjY SǨƮƳDŽP: A Ռȸɏ ȿeʏʖȷʑnɢ ʢisk Podɰɸʙʖng ʓUʋȷʑwʝʁk AsimpleandrobustƤnesedimentriskmodelcanbeextremelybeneƤcialasithelpsustotargetandtailorbothfurther monitoringworkandcatchmentmanagementinterventions. TheSCIMAP Ƥne sediment risk model wasdevelopedthroughacollaborativeprojectbetweenDurhamandLancaster Universities.TheSCIMAPProjectwassupportedbytheUKNaturalEnvironmentResearchCouncil,theEdenRiversTrust, theDepartmentoftheEnvironment,FoodandRuralAơairsandtheEnvironmentAgency.

SUSPENDEDSOLIDS &TURBIDITY

TheSCIMAPmodelgivesanindicationofwherethehighestriskofsedimenterosionriskoccursinthecatchmentby(1) identifying locations where, due to landuse, sediment is available for mobilisation (pollutant source mapping) and (2) combining this information with a map of hydrological connectivity (likelihood of pollutant mobilisation and transportationtoreceptor). ThecombinationofthesedimentavailabilityandhydrologicalconnectivitymapsresultsinaƤnalƤnesedimenterosion riskmodelthatisusefulfortargetingƤeldsurveysandthemitigationoferosionriskatcatchment,farmorƤeldscale.

30


IʛpacWɡ Է ʣXʣȼʑndeɍ VɼʙiGɡ & ʤuʁʍiʏiʤɨ Onthehealthofaquaticecosystems Themostobviouseơectofturbidityonthequalityofwaterisaesthetic,asitgivesthe appearancethatthewaterisdirty.However,suspendedmaterialinthewaterofrivers andlakescanalsocausesigniƤcantdamagetotheecologyoftheaquaticecosystemby blocking the penetration of light to aquatic plants, clogging the gills of Ƥsh and other aquatic organisms, and by smothering benthic habitats. This has the eơect of suơocatingtheorganismsandeggsthatresideintheinterstitialspacesofthesubstrate.

SUSPENDEDSOLIDS &TURBIDITY

Furthermore, where elevated turbidity is the result of algal or other microbial growth theseorganismscanalsohavedirecttoxiceơectsontheecologyoftheecosystem(e.g. toxic blueǦgreen algae) or indirect eơects through the eutrophication of the water column. Suspended material in rivers and streams can also have a signiƤcant impact on the ecologicalhealth,productivityandsafetyofestuarineandcoastalenvironmentsinthe downstreamsectionsoftheircatchments.

Sedimentaccumulationonariverbed

Ontheprovisionofdrinkingwater In addition to their ecological impacts, turbidity and suspended solids also add signiƤcantly to the intensity and cost of drinking water treatment as they can accumulateinanddamagewaterstorageandtreatmentinfrastructure. Suspended sediment must also be eliminated from the water for eơective chlorine disinfectionofthewatertobeachieved. Furthermore, particulates in suspension also carry other damaging and potentially dangerouspollutants,includingmetals,pesticides andnutrients(suchasphosphorus). Onceremovedfromthewater,theresultingsludge,whichmaybecontaminatedwith these other pollutants, must also be disposed of in a safe manner and this can be extremelycostlywhenitisproducedinlargevolumes. Inlightoftheimpactthatturbidityandsuspendedsolidshaveontheeƥciencyandcost ofwatertreatmentandontheaestheticqualityandsafetyoftheƤnaldrinkingwater,it is little surprise that the UK Water Supply (Water Quality) Regulations 2000 indicate thattreateddrinkingwatershouldnothaveturbidityabove1NTU. Inaddition,theECDirectiveontheQualityRequiredofSurfaceWaterIntendedforthe AbstractionofDrinkingWater1975(75/440/EEC)givesguidancethatrawwatershould nothaveTotalSuspendedSolids(TSS)aboveaconcentrationof25mg/lwithouthigher levelsoftreatmentbeingundertakenbeforeconsumption. Inthewatertreatmentprocessesundertakenatwatertreatmentworks,thesuspended materialintherawwater,andhencetheturbidity,isremovedbycoagulationinduced bytheadditionofvariouscoagulants(e.g.alum).Thelevelofturbidityintherawwater has a signiƤcant eơect on the coagulation process. When turbidity is elevated, the amountofcoagulantaddedmustbeincreasedand,atmanytreatmentworks,turbidity (along with colour) is one of the parameters that is constantly measured and used to calibratethedoseofcoagulantusedinthetreatmentprocess. 31

Sedimentpressureisfeltatthe sedimentorsludgepressofthewater treatmentworks(top).Thisgenerates largequantitiesofsedimentorsludge ‘cake’whichmustthenbesafely disposedof(bottom).Dataindicate thatrawwaterpollutedwith suspendedsedimentcandoubleor eventripletheamountofsludge createdataworks.


CDŽSE SƼǟLjY :atʑɠ qXɪʙiʤɨ & ʍiɼOoʔicɪl PʝʜiWʝʢʖng Wɛ detʑʢʛʖȸɏ ȿeʏʖȷʑnɢ ʖʛpacWɡ In 2002, a sediment ‘Ƥngerprinting’ study undertaken on 18 rivers in England and Wales revealed that 69% of the sediment load in the River Tamar was derived from landǦsurface sources and just 31% was from river channel/bank sources(seebelow).ThestudyfoundthatthisratiowasinstarkcontrasttotheƤndingsinotherWestcountryrivers.For example, in the other rivers of the wider Tamar catchment, the Tavy and Plym, just 10% and 8% of the sediment respectivelywerederivedfromsurfacesources(seebelow). TheauthorsbelievedthatthepredominanceoflandsurfacesourcesintheTamarcatchmentwasadirectresultofthe catchments high stocking densities, which subject surface soils beneath pasture to severe poaching and subsequent erosionduringrainstorms.

SUSPENDEDSOLIDS &TURBIDITY

Theprovenanceofinterstitialsedimentsamples collectedfromstudycatchmentsinsouthǦwest England.Sourceapportionmentwasperformed usingthesedimentƤngerprintingtechnique (adaptedfromWallingetal,2002).

Invertebratecommunityassessment IthaslongbeenrecognisedthatbenthicmacroǦinvertebratesaresensitivetotheaccumulationofƤnesedimentinrivers (Cordone&Kelly,1961; Chutter, 1969; Richardset al., 1997)andinrecentyearstheProportion of SedimentǦsensitive Invertebrates(PSI)indexhasbeendevelopedasabiologicalindicatorfortheassessmentofƤnesedimentaccumulation in rivers. The PSI index assigns families and species of benthic macroǦinvertebrates a sensitivity rating from 0Ǧ100 for sediment according to their anatomical, physiological and behavioural adaptations. The scores for the taxa found in a samplearesummedtogivethesampleanoverallPSIscore. The development of the PSI index and its incorporation into the RIVPACS database in 2011 has allowed invertebrate samplingtobeusedasabiologicalmethodfortheassessment of Ƥnesediment load across the Crownhill WTWs catchment. Duplicate(twoseason)invertebratesamplesweretakenat30 locationsacrossthecatchment.EachsamplewasidentiƤedto specieslevelandthePSIindexcalculated. Ateachsamplinglocationenvironmentalmeasurementswere also taken and entered into the River Invertebrates Analysis Tool(RICT),whichusestheRIVPACSdatabasetopredictwhat thePSIindexscoreshouldhavebeenforthatsite. The Ecological Quality Ratio (EQR) for the sample is then calculatedastheratiobetweentheobservedandtheexpected (O/E)score. TheƤndingsofthisinvertebratestudy(aboveright)showthatseveralwaterbodiesintheTamarcatchmentappearto haveinvertebrateassemblagesthatareimpactedbyƤnesediment.Theobservationthatthemostimpactedareasarein theUpperTamar,OtteryandLowerTamarsubǦcatchmentsisentirelyinaccordancewithourpreviousƤndingsandwith theEnvironmentAgencyWFDReasonsforFailuredatabase. Waterchemistrysampling To further investigate the sources of suspended solids in the Tamar catchment, a telemetrically linked multiǦparameter probe (sonde) was installed to identify occasions when heavy rainfall had triggered highǦƪow eventsintheriverandacorrespondingspike intheturbidityoftheriverhadoccurred. Water quality samples were then taken and analysed to identify the relative suspended solids contribution being made by each subǦ catchmentatthosetimes(right). 32


Seʏʖȷʑnɢ ʛiʤiJaʤiʝɚ ȷeaʣureɡ & ʃȱʑʖɠ eɑ£caʎɨ

 EarlyharvestingandestablishmentofcropsinAutumn  CultivationoflandforcropsinSpringratherthanAutumn  Adoptareducedcultivationsystem  Cultivatecompactedtillagesoils  Cultivateanddrillacrosstheslope  Leaveautumnseedbedrough  ManageoverǦwintertramlines  LoosencompactedsoillayersingrasslandƤelds  ReduceƤeldstockingrateswhensoilsarewet  ConstructtroughswithaƤrmbutpermeablebase  Movefeedersatregularintervals

SUSPENDEDSOLIDS &TURBIDITY

There are a wide range of mitigation measures available for reducing sediment loads and turbidity in the aquatic environment. These measures are primarily aimed at reducing the availability of sediment sources, at reducing the likelihood of material beingmobilisedandatdisconnectingthepathwaysviawhichparticulatematter(mainly soil)iscarriedintowatercourses.Measuresinclude:

Blonder1984

Awideandvariedbodyofresearchhasbeenconductedoverthepast40orsoyearsin theattempttoquantifyandunderstandtheprocessesofsoilerosiononagriculturalland intheUKandhowitcanbereduced. There are numerous conservation tillage techniques that have been shown to reduce soilerosionanditiswelldocumentedthatroughsoilsurfacesonarablelandreducerunǦ oơandincreasethewaterholdingcapacityofthesoil,therebypreventingmobilisation andtransportationofparticulatemattertowatercourses. The table below summarises the key Ƥndings from the Mitigation Options for PhosphorusandSediment(MOPS)project—acollaborativeresearchproject,fundedby the UK Department for Environment, Food and Rural Aơairs (DEFRA), andinvolving fourprojectpartners,LancasterUniversity,ADAS,theUniversityofReadingandThe Game&WildlifeConservationTrustAllertonProject.Theprojectwasdesignedtotest the eƥciency of a range of mitigation measures aimed at reducing sediment through conservationtillagetechniques. Mitigationmeasure

Reductioninsuspendedsediment

Contourcultivation

64Ǧ76%

Minimumtillage

37Ǧ98%

TramlinemodiƤcation

75Ǧ99%

Beetlebankconstruction

16Ǧ94%

AmandaSlater

AsubǦsoiler(top)andarough cultivation(bottom)Ǧbothgood methodsformaintaininggoodsoil structurethroughouttheyear

SummaryofkeyƤndingsfromthe MitigationOptionsforPhosphorusand Sediment(MOPS)projectthataimedto testtheeƥciencyofarangeof mitigationmeasuresaimedatreducing sedimentthroughconservationtillage techniques.(FromStevensandQuinton, 2008.)

CDŽSE SƼǟLjY 'ʖrecɢ ʏʢɵɸʙʖng: Ɉ ʛʖʜʖʛum ʤɵɸOaȰɏ teɭʕʜiqɂɏ Directdrillingisasystemofseedplacementwheresoilisleftundisturbedwithcropresiduesonthesurfacefromharvest untilsowing.Seedsaredeliveredinanarrowslotcreatedbydiscs,coultersorchisels. Direct drilling oơers the potential for savings over traditional ploughǦbased crop establishment systems due to lower costs associated with machinery, energy, soil damage, soil erosion, nitrogen leaching and agrochemical losses. It also oơerssubstantialenvironmentalbeneƤts,suchasincreasedsoilfaunaandhabitatsforbirds,aswellasareducedriskof watercoursepollution. The Soil Management Initiative (SMI) Guide to Managing Crop Establishmentsays the method gives ‘a dramatic reduction in establishment costs and an increase in work rate, improved control of black grass andreducedslugactivity’SourceCranƤeldUniversity

System

Depth (cm)

Cost (£/ha)

Time (mins/ha)

Cerealyield (%)

Plough

15Ǧ35

100Ǧ135

150Ǧ220

100

0

30Ǧ45

25Ǧ40

99.2

Directdrilling

33


CDŽSE SƼǟLjY BɤՔʑɠ Sʤʢʖpɡ fʝɠ ȿeʏʖȷʑnɢ pɼɸʙXʤiʝɚ ʛiʤiJaʤiʝɚ As we have described for nutrient pollution, the eƥcacy of buơer strips in reducing suspended sediment loads in watercourseshasalsobeenthesubjectofasigniƤcantbodyofresearch.TheƤndingsofthisresearch,summarisedinthe table below, indicate that buơer strips can reduce sediment losses from between 33 and 100% in plot and Ƥeld experimentsandthatpercentagereductionisprimarilyinƪuencedbybuơerstripwidth. Location

BuơerWidth(m)

SoilTexture

Slope(%)

Eƥcacy (%Sedimentreduction)

Aroraetal.(1996)

USA

1.52

Siltyclayloam

3

40Ǧ100

BlancoǦCanquietal.

Reference

SUSPENDEDSOLIDS &TURBIDITY

USA

0.7

Siltloam

4.9

81Ǧ92

(2004)



4





94





8





98Ǧ99

Borinetal.(2004)

Italy

6

Sandyloam

3

93

Dillahaetal.(1988)

UK

4.6

Siltloam

11Ǧ16

63





9.1





78

Duchemin&Madjoub



3

Sandyloam

2

87

(2004)



9





90

Ghaơarzadehetal.(92)



9.1



7Ǧ12

85

USA

61





80

Denmark

0.5

Sandyloam

7

62



29





100

Norway

5

Siltloam

12Ǧ14

60Ǧ87





10





90

Leeetal.(2000)



7.1

Siltyclayloam

5

70

Limetal.(1998)

Homer&Mar(1982) Kronvangetal.(2000)  Kronvangetal.(2005)

USA

6.1

Siltloam

3

70





12.2





89.5





18.3





97.6

Lynchetal.(1985)



30





75Ǧ80

USA

19



4

62





17



6

38





4



4

64

UK

9.2

Sandyloam

Ǧ

72

Jinetal.(2002)

Magetteetal.(1987) McKergowetal.(2003) Muenzetal.(2006) Pattyetal.(1997)

Australia



Loamyland

<2

93

USA

25

Sandyclayloam

16.5

81

France

6

Siltloam

7Ǧ15

87





18





100

Schellinger&Clausen (1992)



22.9





33

Schmittetal.(1999)



7.5

Siltyclayloam

6

63





15





93

Schwer&Clausen(1989)



26

Sandyloam

2

95

NewZealand

10





87

Verstraetenetal.(2002)

Belgium

20

Siltyclayloam

<2

41

Wong&McCuen(1982)



30.5



2

90





61





95

Youngetal.(1980)

UK

27



4

67Ǧ79

Ziegleretal.(2006)

Thailand

30

Sandyloam



34Ǧ87

Smith(1989)

34


PESTICIDES

PNJSƼIǨǏ'NJS

35


PNJSƼIǨǏ'NJS Chemicalsthatareusedtokillorcontrol‘pest’organismsarereferredtogenericallyas ‘pesticides’.Inagriculturalandhorticulturalusesthesechemicalsaregroupedaccording to their target organisms and include herbicides (weeds), insecticides (insects), fungicides(fungi),nematocides(nematodes)androdenticides(vertebratepoisons). MCPA(herbicide)

Mecoprop(herbicide)

In agricultural applications, pesticides are widely used to protect crops and livestock frompestsanddiseasesand,whenusedwithcare,theycandeliversubstantialbeneƤts forsociety:increasingtheavailabilityofgoodquality,reasonablypricedfoodandwell managedurbanenvironments. Despite the potential beneƤts of pesticide use, however, it is important to note that, followingtheirapplication,largeamountsofpesticideoftenmisstheirintendedtarget andarelostintotheenvironmentwheretheycancontaminatenonǦtargetspecies,air, water and sediments. Pesticides are, by design, harmful to living organisms and so, when they do accumulate in these nonǦtarget locations, they can pose a signiƤcant threattoecosystemhealth,biodiversityandhumanhealthiftherisksarenotaccurately assessedandappropriatemeasurestakentominimisethem.

SʝuUȪeɡ Է ȼeVʤiʎideɡ Pesticidepollutionoccursprimarilythroughtworoutes:

Pointagriculturalsources.Suchasleakage,spillageoraccidentaldirectapplication toawatercourse(forexampleastheresultofspraydrift) Glyphosate(herbicide)

Diơuse agricultural sources. Where active ingredients are washed oơ or leached fromthesoilfollowingtheirapplication.

PESTICIDES

The threat posed by an individual pesticide is also dependent on the unique intrinsic propertiesoftheactiveingredients,whichdeterminethespeciƤcrisktheyposeinterms ofwaterpollutionandtheeaseoftheirsubsequentremovalfromdrinkingwater.These intrinsicpropertiesinclude: Cyromazine(insecticide)

 PesticidehalfǦlife.Themorestablethepesticide,thelongerittakestobreakdown andthehigheritspersistenceintheenvironment.

 Mobility & solubility. Allpesticideshaveuniquemobilityproperties,bothvertically and horizontally through the soil structure. Many pesticides are designed to be solubleinwatersothat theycanbe applied withwaterandeasilyabsorbed by the target.Apesticidewithhighsolubilityalsohasafarhigherriskofbeingleachedout of the soil and into a watercourse. In contrast, residual herbicides have lower solubilitytofacilitatetheirbindingtothesoil,buttheirpersistencyinthesoilcanalso causeproblems.

36


In addition to the intrinsic characteristics of each pesticide, there are also several extrinsic factors that can determine whether a pesticide poses a risk in a particular situation:

 Rainfall.Highlevelsofrainfallincreasestheriskofpesticidescontaminatingwater. Water moving across or through the soil can wash pesticides into watercourses or theycanbetransportedintothewaterboundtotreatedsoilviasoilerosion.

 Microbial activity. Pesticidesinthesoilarebrokendownbymicrobialactivityand thisdegradationisexpeditedwherethelevelsofmicrobialactivityarehighdueto the presence of high numbers of microbes or elevated soil temperature. Pesticide residuescanalsobedegradedthroughevaporationandphotoǦdecomposition.

 Application rate. The more pesticide that is applied, the longer signiƤcant concentrationsremainavailabletobetransportedintothewater.

 Treatment surface. Pesticides are generally designed to be applied to soilǦbased systemswheretheyareheldbeforebeingtakenupbythetargetorganism.When pesticidesareappliedtononǦporoussurfaces(suchasconcreteortarmac)ortosoil that is degraded, they are not absorbed by the soil and are therefore particularly vulnerabletomobilisationintowatercoursesfollowingrainfall.

CDŽSE SƼǟLjY The principal aim of this approach is to identify areas where the use of pesticides applied to the land represents a pollutionriskduetoanelevatedlikelihoodthattheywillbemobilisedandtransportedthroughoroverthesoilandintoa watercourse. A number of proprietary tools and modelling approaches have been developed to assess the spatial risk of pesticide pollution.TheseincludetheCranƤeldUniversityCatchIStool,theADASPesticideRiskAssessmentModelandtheGfK KyneteciǦMAPWatersystem,butallareessentiallybasedonsimilarconceptualmodels. WeusedtheiǦMAPWatersystemtomodelpesticideapplication rates across the subǦcatchments of the Tamar catchment. It is generally accepted that, while the iǦMAP dataset is robust at catchment or subǦcatchment scale, its aggregation to a Ƥner scale than the subǦcatchment level would result in signiƤcant inaccuracyintheƤnalmodel. To achieve our modelling aim we developed a spatial mapping protocol (summarised right), which is essentially based on the applicationrateofthepesticide(derivedfromtheiǦMAPsystem), the landuse for which it is used, the propensity of the soil to release pesticides by leaching or runǦoơ, and the hydrological connectivityoftheland. Using this method we have developed risk models for all of the active ingredients detected in the Crownhill water treatmentworkscatchment.Riskmapsderivedfortwoacidherbicides;MecopropandMCPA,andoneneutralherbicide; Chlorotoluronareshownbelow.

37

PESTICIDES

AVȿeVʣʖng ȼeVʤiʎidɏ pɼɸʙXʤiʝɚ ʢisk Xʣʖng Ɉ ʣpaʤiɪl Podɰl


CDŽSE SƼǟLjY AVȿeVʣʖng ȼeVʤiʎidɏ pɼɸʙXʤiʝɚ Ooaɍ Xʣʖng paVʣʖɃɏ Vʋʛɿʙʖng Taking samples of river water using the conventional method of Ƥlling bottles by hand can be costly and timeǦconsuming. The results obtained from these ‘spot’ samplescan,atbest,onlyprovideasnapshotoftheconcentrationtargetcompounds whichmaybepresentatthetimeofsampling. Subsequentinterpretationoftheanalyticalresultsobtainedisalsodiƥcult(wasitthe leadingedgeofapollutantplume,thepeak,orthetrailingedge?)andthetimelag between these results and repeat samples or remedial action inevitably means the environmentalinvestigationisreactiveinnature. Recently, a number of alternative and innovative monitoring strategies have been proposedtoovercomethesechallenges.Inparticular,researchisfocusingontheuse ofpassivesamplerswhichcanbedeployedaloneor,moreoften,inconjunctionwith spotsamplingtoprovideadditiondataonwaterqualityandpollutantloadsinrivers. Recently, a research collaboration between South West Water, the University of Portsmouth,Natural Resources Wales andtheWestcountry Rivers Trust hasbeen established to use the ChemcatcherTMpassivesampler(developedat theUniversity) toinvestigatewaterqualityinthisarea.

PESTICIDES

Chemcatcher™ is a small plastic device Ƥtted with a speciƤcally tailored receivingǦ phase disk that has a high aƥnity for the target compounds of interest. Diơerent phases are available to sequester nonǦpolar (e.g. polyǦaromatic hydrocarbons and some pesticides) and polar pollutants (e.g. pharmaceuticals and personal care products), heavy metals (e.g. cadmium, copper, lead and zinc) and some radioǦ nuclides(e.g.caesium). In practice, the receiving phase disk is overlaid with a thin diơusionǦlimiting membrane.Thesedevicescanbeusedtoobtaintheequilibriumconcentrationofthe pollutants or more typically the timeǦweighted average (TWA) concentration over thesamplingperiod. TheƤrstriverinetrialsusingtheChemcatcherTMinvolvedinvestigating pesticides along the River Exe; a river designated as a WFD Article 7 Drinking Water Protected Area (DrWPA) with additional Safeguard Zone (SGZ)status that requires aformal ‘actionplan’tobe drawn up by the Environment Agency. Here the aim was to ‘Ƥeld test’ the techniqueandhopefullyprovideanunderstandingofwheretheworst problempesticideloadingsandlocationswere. Over a twoǦweek period in early May 2013, timed to coincide with known agricultural applications and forecasted rainfall, a number of devicesweredeployedalongmuchofthelengthoftheriver. ChemcatcherTM samplers were housed in a number of specially fabricated metal cages supplied by Anthony Gravell, Technical Specialist at Natural Resources Wales Llanelli Laboratory, who specialises in passive sampling in conjunction with HPLCǦMS techniques for the analysis of pesticides, pharmaceuticals and endocrine disruptors in various environmental compartments. Each cageheldthreereplicatesamplingdevicesandwasweightedtoensure stability(seeimagesright). Priortothetrials,researchersattheUniversityandSouthWestWater’s OrganicsLaboratoryworkedtogethertoidentifyareceivingphasedisk capable of sequestering a group of nine speciƤc pesticides that are commonlydetectedinrawwatersintheSouthWest. PriortotheƤelddeployment,laboratorytestswereundertakenusingalargetankƤlledwithRiverExewaterandspiked withknownconcentrationsofthepesticidesunderinvestigation.Heretheaimwastomeasuretheuptakekinetics(and hencethesampleruptakerates)ofthesechemicalsoveratwoǦweekperiod.Oncethesedatawereavailable,theywere thenusedtoestimatetheTWAconcentrationsofthesepollutantsintheriverovertheƤeldtrialperiod.

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IʛpacWɡ Է ȼeVʤiʎideɡ Onthehealthofaquaticecosystems Pesticidescontainactiveingredientsdesignedtokillcertaingroupsoforganismsand, as such, there is signiƤcant potential for them to pose a threat to the health of other nonǦtargetspecies(includinghumans),habitatsandecosystemswhentheyaccumulate intheenvironment. Directeơectsofpesticidesonvertebrateshavebeengreatlyreducedsincethephasing out of organochlorines, but there are a number of active ingredients, such as the molluscicide methiocarb, which have been shown to exert toxic eơects on vertebrate nonǦtargetspecies(Johnsonetal.,1991). Many herbicides are also known to have negative impacts on invertebrate abundance andspeciesdiversity(ChivertonandSotherton,1991;Moreby,1997),whileinsecticides have been shown to have signiƤcant impacts on both terrestrial and aquatic invertebrate communities (e.g. Moreby et al., 1994). Some fungicides have also been implicatedinreducinginvertebrateabundance(e.g.Reddersenetal.,1998). Otherstudies(Williamsetal.,1995)haveshownthatpesticideƪushescanoccuratthe headwaters of streams, where stream fauna could be aơected. This is of particular concern because such waters are otherwise of high quality and may be Ƥsh nursery grounds.

AsaresultoftheseƤndings,theWaterFrameworkDirectivesetsthresholdsformany keypesticides,suchasDiazinon,LinuronandCypermethrin,abovewhichtheymaybe expected to be damaging the aquatic environment and/or pose a threat to human health (soǦcalled ‘speciƤc pollutants’). The WFD also sets targets for several high toxicity(andlargelybanned)pesticides,suchasAtrazineandDDT,whichareclassiƤed as‘priority’ordangeroussubstancesundertheEUDangerousSubstancesDirective.

CDŽSE SƼǟLjY AVȿeVʣʖng ȼeVʤiʎidɏ pɼɸʙXʤiʝɚ ʠreVʣurɏ Xʣʖng ʋɚ ʖʜɃɏԮɰʍUatɏ ʖndʑx: ǜPƩAR AnotherapproachwehaveadoptedistheassessmentofinvertebrateassemblagesusingthenewlydevelopedSPEcies At Risk Ǧ Pesticides (SPEARPESTICIDES)index(LiessandvonderOhe,2005).Thisindexassessesthedegreetowhichthe invertebrateassemblagesintheriverarebeingaơectedbythepresenceofpesticides(andinsecticidesinparticular)using thelifeǦhistoryandphysiologicaltraitstodevelopsensitivityscoresforeachspecies. Thecontinuousexposureoftheinvertebratefaunainastreamtothepesticideloadinthewatermakesthemanexcellent indicatorofpesticidepressureacrossacatchmentinawaythatwaterqualitysamplingcannotachieveunlessundertaken withveryhighfrequency. In 2011, the SPEARPESTICIDES index was also added to the River InVertbrate Prediction and ClassiƤcation System (RIVPACS) database and this facilitated its use in the same year as a biologicalmethodfortheassessmentofpesticidepressureacross theCrownhillwatertreatmentworkscatchment. InvertebratesamplestakenacrossthecatchmentwereidentiƤed to species level and the SPEARPESTICIDES index calculated. The RiverInvertebratesAnalysisTool(RICT)wasthenusedtopredict what the SPEARPESTICIDES index score should have been for that site and the Ecological Quality Ratio (EQR) for the sample calculated as the ratio between the observed and the expected (O/E)score. The Ƥndings of the Crownhill WTWs catchment SPEARPESTICIDES invertebratestudyaresummarisedinthemap(right).

39

PESTICIDES

Mostrecently,in2013,anextensiveanalysisoftheeơectsofpesticidesoncommunities of stream invertebrates in Europe and Australia found that they caused signiƤcant eơectsonboththespeciesandfamilyrichness,withlossesinspeciesrichnessofupto 42%recorded(Beketovetal.,2013).


Advancedwatertreatmentsolutions requiredtoremovepesticidesfrom drinkingwaterincludepowdered activatedcarbon(top),granular activatedcarbon(GAC)Ƥlters(middle) andultraƤltration(bottom).

Ontheprovisionofdrinkingwater Watercompaniesarerequiredbylawtoassesstheriskthatpesticidesposetoeachof their raw water sources and also to monitor these sources for the presence of any of thesecompounds. The European Drinking Water Directive stipulates that there must be no individual pesticide detected in drinking water at concentration over 0.1 Ɋg per litre. However, overrecentdecades,asaresultofthisstringentstandard,thecontinuedcontamination ofriverandgroundwatersourceswithpesticideshasdrivenwatercompaniestoinvest inevermoreadvancedwatertreatmentprocessestoremovethemfromdrinkingwater. There are several methods available for the removal or reduction of pesticide concentrations in treatment of drinking water. Blending with water from an unǦ contaminatedsourcecanbeeơectiveascanblendingtreatedwater,butthesemethods oftenrequirelengthyandcostlytransfersofwateroraresimplynotfeasible. At the water treatment works, the methods available for the reduction of pesticide concentrations can be divided into adsorption processes, biological processes, destructionprocessesandphysicalremovalprocesses.Theseinclude:

     

Granularactivatedcarbon(GAC)Ǧadsorption Powderedactivatedcarbon(PAC)Ǧadsorption OzoneǦGAC–destruction/adsorption/biological UltravioletirradiationǦdestruction AdvancedoxidationǦdestruction NanoǦƤltrationǦreverseosmosis–physicalremoval(sizeexclusion)

PESTICIDES

All of these processes are expensive to undertake, in terms of both the infrastructure investment required and their running costs, and all are highly energy and resource intensive. Furthermore,thereareanumberofpesticidesforwhichthesehighǦintensityprocesses can remain ineơective (such as metaldehyde; see below) and there remains a considerableriskthatthesecontaminantscouldstillbepassedonintotheƤnaltreated watersuppliedtocustomersiffurtherprecautionsarenottaken.

Metaldehydeisaselectivepesticide usedbyfarmersandgardenersto controlslugsandsnailsinawidevariety ofcrops.Technicallyitisknownasa ‘molluscicide’anditsactionisvery speciƤctoslugsandsnails) Metaldehydeissoldunderavarietyof brandnamesinpelletform. Metaldehydeisanissueforwater companies,becausepelletsappliedto cropsonlandcanƤndtheirwayinto drainsandwatercourseseitherdirectly duringapplicationorasaresultofrun oơduringhighrainfallevents.Levelsof metaldehydehavebeendetectedin traceconcentrationsintheriversor reservoirsatlevelsabovetheEuropean andUKstandardssetfordrinking water.Currentdrinkingwater treatmentmethodsarenoteơectiveat reducingthelevelsofmetaldehydein water.Therehavebeenoccasionswhen verylowlevelsofmetaldehydehave beendetectedintreateddrinking water.Theselevelsareextremelylow– thehighestbeingaround1ug/land mostlymuchlower.Howeverthelevels areabovetheEuropeanandUK standardsforpesticidesindrinking waterthatissetat0.1ug/l.

40


PeVʤiʎidɏ ʛiʤiJaʤiʝɚ ȷeaʣureɡ & ʃȱʑʖɠ eɑ£caʎɨ Highpesticideinputstowatercoursesaremostlikelytooccurduetodirectapplication or when rainfall causes surfacerunǦoơ or leaching shortly after application. Mitigation measurestoreducepesticideinputsthereforefallintothreemaincategories:

 Best practice advice and education. Encouraging measures to prevent direct applicationorpointǦsourcelossofpesticidestoawatercourseordrainagesystem.

 Land management and soil management advice. Soil management measures to preventrapidrunǦoơorleachingwhichensurethatpesticidesaretakenupbytarget speciesorbrokendowninthesoilratherthanbeingavailabletocausepollution.

 Landusechangeandtheimprovementoffarminfrastructure.Mitigationmeasures

Pesticidebestpracticeadvice&education Manypesticidecontaminationsoccurastheresultofpoorpracticesundertakenduring their transportation, storage, preparation or application. These so called pointǦsource inputsofagriculturalpesticidesmainlyoccurfromhardimpermeablesurfaces(suchas farmyards, storage facilities or roads), which become contaminated during the Ƥlling and cleaning of sprayers, improper disposal of unǦused mix, leaks from faulty equipment,incorrectstorageofcanistersandwashingofequipment. Once present on these surfaces pesticides are then available to be washed into an adjacentwatercourseortoentertheseweragesystem,whichthentransportsthemto the sewage treatment works and on into the aquatic environment via the works discharge.Directcontaminationoftheaquaticenvironmentcanalsooccurastheresult ofspraydriftorwhenpesticideapplicationisinaccurateandoccursoutsidetheconƤnes ofthetargetƤeld. StandardsfortheuseandmanagementofpesticidesintheUKaresetoutbyBASISand theHealthandSafetyExecutiveand,in2001,thefarmingandcropprotectionindustry established the Voluntary Initiative to promote best practice in the use and managementofpesticidesandtominimisetheirenvironmentalimpacts.

CDŽSE SƼǟLjY Tȱɏ VɼʙunWʋʢɨ IʜiʤiaʤʖɃɏ TheVoluntaryInitiative(VI)beganinApril2001.ItisaUKǦwidepackageofmeasures, agreedwithGovernment,designedtoreducetheenvironmentalimpactoftheuseof pesticides in agriculture, horticulture and amenity situations. Initially a list of 27 proposals, the programme Ƥnally included over 40 diơerent projects covering research,training,communicationandstewardship. The combined cost of the programme between 2001 and 2006 to the farming industry,thecropprotectionindustry,thewaterindustryandotherswasestimatedto be£45Ǧ47m,butduringthattimetheyworkedto:

 Improve awareness among farmers of the potential environmental risks arising from pesticide use; improve the competence of advisors and improve Ƥeld practicesofsprayoperatorsandoptimisetheperformanceoftheirmachines.

 Engage the farming unions and establishment of Crop Protection Management Plans (CPMPs) as a selfǦaudited means of assessing and planning the environmentalaspectsofcropprotectionactivitiesacrossthewholefarm.

 EstablishalowǦcostsprayertestingscheme(NSTS)withanationwidenetworkof 294testingcentresand465certiƤcatedtesters.

 EstablishtheNationalRegisterofSprayOperators(NRoSO),throughwhichspray operators can demonstrate a commitment to best practice in pesticide handling andapplication.

 CreateaseriesofEnvironmentalInformationSheetsasanaidtoriskmanagement forallproductssoldbymembersoftheCropProtectionAssociation. 41

Thereareanumberofcomprehensive guidesongood/bestpracticestobe undertakenwhenusingpesticides, includingtheCodeofPracticeforUsing PlantProtectionProducts(below).

PESTICIDES

(e.g. buơer strip and riparian wetlands) designed to intercept surface runǦoơ and ensurepesticidesarebrokendownbeforereachingthewatercourse.


PerhapsthesimplestmethodforthereductionofpointǦsourcepesticidepollutionisto reduce the number of sprayer Ƥlling and cleaning actions undertaken by encouraging farmers to share the use of spraying equipment. In addition, numerous studies have foundthattheadoptionofgoodorbestpracticeswhenusingpesticidescanensurethat theriskofenvironmentalcontaminationisminimised(KreugerandNilsson,2001). The best management practices shown to be eơective include Ƥlling and cleaning sprayersonlyontheƤeldoronabiobed(FelgentreuandBischoơ,2006;Vischettietal., 2004),carefulhandlingandstorageofpesticidesandsaferstorageofemptycontainers (Higginbotham,2001),applyingtankmixandcontainerleftoversindilute form to the Ƥeld(JaekenandDebaer,2005),andnoapplicationofpesticidesonthefarmyard.

Apesticidehandlingareaisthesite wherethesprayerisƤlledandisoften alsousedforsprayerwashing,nozzle calibration,sprayertesting, maintenanceandstorage. Abiobedisamixtureofpeatfree compost,soilandstraw(biomix) coveredwithturfthatisplacedina linedpit(seeright).

Overall, stewardship initiatives and application of best management practices have been shown to achieve a reduction in the total river load of 40–95% in a number of catchment studies (Reichenberger et al., 2007; Kreuger and Nilsson, 2001; MailletǦ Mezeray et al., 2004). However, in most catchment studies, it was also found that continuedeơortisessentialtoensurecontinuedprevention. Another powerful method for the collection and disposal of pesticideǦcontaminated water is the biobed. A biobed consists of a pit or container Ƥlled with a mixture of chopped straw, peat and topsoil that rapidly degrades any pesticide entering the bed throughmicrobialactivity.

PESTICIDES

Liquidsenterthebiomixwithinthe biobedbygravitydrainageorapump. Oncetheretheythenundergo bioremediationbeforebeingdrained fromthebiobed.Thisdrainedliquid, whichcontainsminimalpesticide residues,canbeusedforlandirrigation orreǦusede.g.forsubsequentsprayer washing.

CDŽSE SƼǟLjY MiʤiJaʤʖng ȼeVʤiʎidɏ pɼɸʙXʤiʝɚ ʖɚ 'ʢɔԲ ReȿʑʢYʝʖɠ, Cʝʢʜwɪɸl Overtheperiod1996Ǧ2010,SouthWestWater’sDrift Water Treatment Works recordedasteadyincreaseinboththe numberofpesticidedetectionsperannumandthedetectedconcentrationofindividualpesticidecompoundsinboththe raw and Ƥnal water. During this period there were 54 positive detections for pesticides in the raw water within Drift Reservoirrepresenting14diơerentcompounds. The chart below shows that, in recent years, herbicide detection results for a number of chemical compounds have showndiscretehigh,narrowspikesindicativeofindividualpollutionincidents.Thisincreasingriskandfrequencyofwater qualityfailurehasledSouthWestWatertotakeatwoǦprongedapproachatDrift.First,anadvancedwatertreatment plant was installed at the treatment works, with a capital cost of £4 million and an annual running cost of £30,000, in ordertoensuretheƤnalwatermetDrinkingWaterInspectoratestandards. Concurrently,fundingof£100,000was investedinaprogrammeoflandowner engagement, agricultural training, and farm intervention work upstream of the reservoir, to address these rising chemical detections at source. These interventionsarebeingdeliveredinthe catchment through Cornwall Wildlife Trust’s Wild Penwith Project,whichis working in partnership with South West Water to provide landowners across the Drift catchment with a number of advisory, educational and infrastructureimprovementmeasures.

Continuedoverpage...

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MitigatingpesticidepollutioninDriftReservoir,Cornwall...continued….

CornwallWildlife Trust’s Wild Penwith project is workingin partnershipwithSouthWest Watertoprovidelandowners acrosstheDriftcatchmentwith:

OneǦtoǦonefarmadvisoryvisits,includinganassessmentofcurrentfarmpractices,andprovisionofwaterprotection bestpractice;

Freeagriculturaltrainingevents,suchasweedmanagement; AcapitalǦgrantaward,funding,forexample,improvedpesticidehandlingandstorageareas. In February 2013, Wild Penwith ran a weed management training day on a dairy farm adjacent to Drift Reservoir. Following presentations on the cultural, mechanical and chemical control of weeds, local farmers visited the water treatment works at Drift to learn more about the complexitiesofdrinkingwatertreatment. Peter James, who farms at Little Sellan adjacent to Drift Reservoir said, “As a farmer, I am very pleased that South West Water is taking this proactive approach in our river catchment. We are now more aware of both the water companies business, and how important our activities on the farm are to the drinking water treatment process. I believe working in partnership in this way will be of beneƤt to everyone.”

PESTICIDES

These farm activities are supported by a comprehensive programme of water chemistry sampling (monitoring herbicides,insecticidesandfungicides)onthereservoir’stwo feeder streams. Water samples are regularly collected with theconsentandcoǦoperationofeachlandownerinvolved. FollowǦup samples can be taken from a wider network of additionalfarmsasrequired.Usingthissystem,thesourceof any inǦreservoir or inǦriver pesticide detection can be traced back to individual farm holdings and advice and guidance giventomitigatetheproblem. Landmanagersarethenmadeawareofthedrinkingwaterissues,andoơeredoneǦtoǦonewaterprotectionbestpractice adviceandotherfarminterventionsfromtheWildPenwithteamasappropriate.Inadditiontothischemicalmonitoring programme, biological monitoring has also been undertaken in the catchment, including the assessment of macroǦ invertebrates,macrophytes(largeaquaticplants)anddiatoms(benthicalgae). Minimising the levels of pesticides found in the raw water could result in South West Water savings on treatment plant operating costs. Wider environmental gains include improved wetland and stream habitat quality,andassociatedenhancedbiodiversity. This is a fantastic example of South West Water’s ‘Upstream Thinking’ project working to deliver improvedwaterqualityinasmallreservoircatchment. Through the wider Wild Penwith Living Landscape project,CornwallWildlifeTruststaơgainedtherespect andtrustoflocalfarmers,whichenablesthemtotackle theseimportantdrinkingwaterqualityissuestogether.

Furtherinfo:www.cornwallwildlifetrust/wildpenwith

43


Landmanagement&soiladvice It has been widely demonstrated that any improvements in soil or land management, suchasimplementationofconservationtillagetechniques,thatreducetheriskofrunǦ oơ and soil erosion are also likely to reduce the risk of a pesticide being mobilised followingitsapplicationtotheland.Inaddition,theincorporationof organic material intothesoilhasalsobeenshowntoincreasethesorptionofsomepesticides;reducing theirmobilityandthelikelihoodthattheywillbelostthroughleaching.

Riparianbuơerstripsand‘conservation headlands’canreducepesticide damagetoadjacentnaturalhabitats.

Interestingly,severalstudieshaveshownthatthepresenceofsubǦsurfacelanddrainage alsoreducesthelossofpesticidesthroughsurfacerunǦoơ.ThisƤndingissupportedby hose of a study of autumnǦapplied pesticides on clay loam soils in north east England wherelossesfromanunǦdrainedplotwerefoundtobeupto4timeslargerthanfroma moleǦdrainedplot(Brownetal.,1995). In contrast to these Ƥndings, however, it is also important to note that there is considerableevidencethatovereƥcientdrainagemayalsogeneratesigniƤcantlossof pesticides through leaching and drain ƪow. The risk factors that lead to pesticide loss through leaching and drainage are poorly understood, but it seems that active ingredient mobility, application rate, soil type and rainfall may all contribute to the generationofpollutionviathisroute. Wherepesticidelossviadrainageisconsideredathreat,theuseofcollectionpondsor wetlandsattheoutƪowarejusttwomeasuresthatcouldworktomitigatetheriskthat areceivingwatercoursewillbecontaminated. Landusechange&theimprovementoffarminfrastructure Perhapsthemoststudiedinterventionsforthemitigationofdiơusepesticidepollution are buơer strips around Ƥelds (conservation headlands), riparian buơer strips and constructedwetlands.

PESTICIDES

Thesefeaturesnot onlyreducetherisk ofspraydriftcontaminating adjacent habitats and watercourses, but they also act to disconnect pesticide pollution pathways by promotingtheinƤltrationofrunǦoơwaterscarryingthemintoaquaticenvironments.

CDŽSE SƼǟLjY BɤՔʑɠ Sʤʢʖpɡ fʝɠ ȼeVʤiʎidɏ pɼɸʙXʤiʝɚ ʛiʤiJaʤiʝɚ As we have described for nutrient and sediment pollution, the eƥcacy of buơer strips in reducing pesticide losses to watercourseshasalsobeenthesubjectofasigniƤcantbodyofresearch(mainlyatplotǦorƤeldǦscale).TheƤndingsofthis research,summarisedbelow,indicatethatbuơerstripscanbehighlyeơectiveinmitigationofpesticidepollution. Inoneofthemostcomprehensivereviewsundertakenontheeơectivenessofbuơerstripsinthemitigationofpesticide pollution, Reichenberger et al. (2009) summarised the Ƥndings of 14 publications that between them assessed the performanceof277diơerentbuơerstrips.Thepesticideloadreductionsforactiveingredientsinsolution(belowleft,63 datapoints)andboundtosediment(belowright;214datapoints)aresummarisedbelow. Overall, buơer strips of all widths were found to be eơective in the mitigation of pesticide loss from Ƥelds and were especiallyeơectivewhentheywerevegetatedandwhenrunǦoơƪowwasslowedsuƥcientlytoenablewaterinƤltration.

44


MICROBES&PARASITES

ƳIǨƺƵBNJS & ƸAƺDŽƻITNJS

45


MIǨƺƵBNJS & PAƺDŽƻITNJS Twoprincipalbacterialgroups,coliformsandfaecalstreptococci,areusedasindicators ofpossiblesewagecontaminationinwaterbecausetheyarecommonlyfoundinhuman and animal faeces. Although these bacteria, which are often referred to as faecal indicator organisms(FIOs), arenot typically harmful themselves,theydo indicate the possible presence of pathogenic (diseaseǦcausing) bacteria, viruses, and protozoans thatalsoliveinhumanandanimaldigestivesystems. Cryptosporidiumoocystsundera ƪuorescencemicroscope.

Anothergroupofmicrobialpollutantsderivedfromhumanandanimalfaecalmaterial which pose a signiƤcant risk to human health, either when people come into contact with the river water or when contaminated water is abstracted for drinking water treatment,areparasiticprotozoainthegenusCryptosporidium. Cryptosporidiumistransmittedthroughtheenvironmentashardyspores(oocysts)that, once ingested, hatch in the small intestine and result in an infection of intestinal epithelialtissue.Theresultingcondition,Cryptosporidiosis,istypicallyanacuteshortǦ term diarrheal disease but it can become severe and chronic in children and in other vulnerable or immunoǦcompromised individuals. In humans, Cryptosporidium can persist in the lower intestine for up to Ƥve weeks; from where it continues to shed oocystsintotheenvironment.

BacteriaEscherichiacoli.

MICROBES&PARASITES

SʝuUȪeɡ Է ʛiʎUɼʍiɪl cʝnWʋʛʖnaʤiʝɚ The most commonly tested faecal bacteria indicators are total coliforms, faecal coliforms, and faecal streptococci. Total coliforms are a group of bacteria that are widespreadinnatureandwhichoccurinmanymaterialsincludinghumanfaeces,animal manure,soil,andsubmergedwood.Theusefulnessoftotalcoliformsasanindicatorof faecal contamination therefore depends on the extent to which the bacteria species foundarefaecalandhumaninorigin. Forrecreationalwaters,totalcoliformsarenolongerrecommendedasanindicator,but for drinking water, total coliforms are still the standard test because their presence indicatescontaminationofawatersupplybyanoutsidesource. Faecal coliforms are a subset of the total coliform bacteria and are more speciƤcally faecalinorigin.Faecalstreptococcialsooccurinthedigestivesystemsofhumansand other warmǦblooded animals. In the past, the ratio between the level of faecal streptococci and faecal coliforms was used to determine whether bacterial contamination wasofhumanornonhumanoriginand,whilenolongerrecommended asareliabletest,thismethodcanstillgiveanindicationofthepotentialsource. There are three principle mechanisms via which faecal material, parasites and faecesǦ derivedsubstances(e.g.ammonia)maketheirwayintoawatercourse.Theseinclude:

 Direct‘voiding’intothewaterbylivestockintheriver.  WashǦoơ and leaching of manure or slurry onthelandsurfaceoraccumulatedon yardsortracks.

 FromconsentedorunǦconsenteddischargesofuntreatedhumansewage. 46


Unrestrictedaccessoflivestocktoawatercourse

Whenconsideringmicrobialcontaminationisitimportanttoexaminethecontribution that these diơerent potential sources make to the load in the water column in any particularlocation. Analysis of data from 205 river and stream sampling points spread widely across mainlandUKhasshownthatmicrobialloadistypicallycorrelatedwithhighƪowrather than low ƪow condition and that urban and grassland landscapes make the most signiƤcantcontributiontotheload(Kayetal.,2009). Further studies have also shown that faecal indicator organism (FIO) loads in catchmentswithhighproportionsofimprovedgrasslandwereshowntobeashighas fromurbanisedcatchmentsandinmanyruralcatchmentsι40%ofFIOmaybederived fromagriculturalsources(landsurfaceandfarmyardinfrastructure). This strong correlation between high ƪow and contamination levels has also been shown to be the case for cryptosporidium and outbreaks of cryptosporidiosis are stronglylinkedtoananimaltohumantransmissionpathwayfollowingperiodsofheavy precipitation(Lakeetal.,2005).

Interestingly, in contrast to these Ƥndings of Kay et al, a detailed study of the River Ribble catchment undertaken in 2002 found that over 90% of the total FIO load enteringtheRibbleEstuarywasdischargedbysewagerelatedsourcesduringhighƪow events. At times of low ƪow the principal sources of FIOs has been shown to be from point sources, such as sewage treatment works, septic tanks and misconnections in the seweragesystem.

IʛpacWɡ Է ʛiʎUɼʍiɪl cʝnWʋʛʖnaʤiʝɚ Onthehealthofaquaticecosystems When animal and human faecal material and the microbes it contains, enter a river system they can exert severe negative impacts on the ecological health of the ecosystemslocallyandfurtherdownthecatchmentinanumberofways. First, the elevated levels of turbidity reduce the levels of light penetrating the water column and this can aơect the plant communities present in the system. This can be particularlyproblematicinthedeeperandecologicallysensitivewatersoftheestuaries andcoastalregionsatthebottomofarivercatchment. MoresigniƤcantly,however,istheeơectthatthemetabolicactivityofaerobicbacteria decomposingorganicwastehasonthelevelsofdissolvedoxygeninthewatercolumn. Where thelevels oforganicmaterial andhencethemicrobial activityin the waterare hightheBiologicalOxygenDemand(BOD)inthewaterwillbeelevatedandthelevels ofdissolvedoxygenavailableforotherplantsandanimalslivinginthewaterwillfall. Eventuallythisdepletionofdissolvedoxygenwillbecomesoseverethattheecological health of the river ecosystem will be degraded as Ƥsh and invertebrate communities begintosuơer. 47

eutrophication&hypoxia

MICROBES&PARASITES

Itisassumedthattheremainingloadattimesofhighƪowisderivedfrompointsources such as sewerage treatment works, misconnections in the sewerage system and combinedseweroverƪows(whichdischargewhensewagetreatmentworksreachtheir maximumtreatmentcapacity).


Ontheprovisionofdrinkingwater,recreation&Ƥsheries The total level of microbial contamination in water and the level of diơerent faecesǦ derivedbacteriaarebothusedasindicatorsofthepotentialpathologicalriskposedby that water. In addition, faecal material may also contain other pathogenic organisms, such as Cryptosporidium, which cause gastrointestinal infections after ingestion or otherswhichcauseinfectionsoftherespiratorytract,ears,eyes,nasalcavityandskin.

Cryptosporidiosis(theCryptosporidium pathogeniclifecycle)(top)anda micrographshowingcryptosporidium oocystsalongsideGiardialamblia (anotherparasite)(bottom).

Whenanimalandhumanfaecalmaterialenterariversystemtheycanthereforeposea signiƤcant threat to the health of people who rely on that water for drinking water, recreationorthesustenanceofƤsheriesandshellƤsheriesindownstreamregionsofthe rivercatchment. Asaresultofthisthreat,signiƤcantstepsmustbetakenatthewatertreatmentworks toremovemicrobialcontaminantsfromdrinkingwater.Thereareanumberofmethods for the disinfection and Ƥltration of drinking water and all must be undertaken with increased intensity if the microbial load in the abstracted raw water increases signiƤcantlyatcertaintimes. The EC Drinking Water Directive also requires that drinking water should not contain anymicroǦorganismorparasite(suchasCryptosporidium)ataconcentrationthatwould constituteapotentialdangertohumanhealth.Cryptosporidiumisparticularlyadeptat breakingthroughthestandardsuiteoftreatmentprocessesundertakenatmanyworks (such as sand Ƥltration and chlorination) and the Drinking Water Inspectorate now requires water companies to implement raw water monitoring, to undertake comprehensive risk assessments and to design and continuously operate adequate treatmentanddisinfectionforcryptosporidium. Inadditiontotheseincreaseddemandsfordisinfection,itisalsoimportanttonotethat thepresenceofelevatedlevelsoffaecalmaterialalsomakeasigniƤcantcontributionto theturbidityandsuspendedsolidloadintherawwater.Asalreadydescribedpreviously thelevelsofturbidityintherawwaterareusedtocalibratethewatertreatmentprocess and, when elevated, will increase the costs of coagulation and sludge management processesundertakenatthedrinkingwatertreatmentworks.

CDŽSE SƼǟLjY Baʃʕʖng watʑɠ VWʋnGʋUGɡ ʖɚ ʃȱɏ ǟK

MICROBES&PARASITES

TheEuropeanUnionbeganworktoregulatetheprovisionofcleanandhealthybathing watersinthe1970sandin2006theECBathingWaterDirectivewaspassedtopreserve, protectandimprovethequalityoftheenvironmentandtoprotecthumanhealth. Themonitoringandimprovementofwaterqualityatbathingwatersthat areatriskof failing the standards set out in the European Bathing Water Directive are the responsibility of the Environment Agency. They take weekly water samples from over 500coastalandinlandbathingwatersinEnglandandWalesduringthebathingseason (MaytoSeptember). These samples are tested for contamination with bacteria such as Escherichia coli and intestinal enterococci which, although not directly harmful in themselves, do indicate a decrease in water quality and give an indication of when pathogenicmicrobesmaybepresentinthewater. Prior to 2012, water samples taken at bathing waters were analysed forTotalcoliforms,FaecalcoliformsandFaecalstreptococci;however this has changed in preparation for the revised bathing water directive, which sets more stringent water quality targets to achieve by2015. In addition to improving water quality at bathing waters the revised Directive also places much greater emphasis on managing beaches andprovidinginformation.From2016,BathingWaterControllers(any local authorities, water companies and businesses in control of the landimmediatelynexttobathingwaterswherepeopleswim)willalso have to provide information to the public about the quality of their bathingwaterandadvisepeopleiftherehasbeenapollutionincident. 48


MiʎUɼʍiɪl ʛiʤiJaʤiʝɚ ȷeaʣureɡ & ʃȱʑʖɠ eɑ£caʎɨ There are numerous highly eơective methods designed to reduce the microbial contaminationofwatercourses,estuariesandcoastalwaters.Whichofthesemeasures isrequireddependsentirelyonthesourcesfromwhichthecontaminationisderivedina particularcatchment.

TheWestcountryRiversTrustfarm measurefactǦsheetscanbefoundat— http://tinyurl.com/kqpyctv.

If a domestic sewage treatment works or septic systems are found to be discharging signiƤcantlevelsoffaecalmaterialandbacteriaintoawatercoursethentheadditionof further‘tertiary’ treatment processes,suchasdisinfectionmayberequiredtoremove highlevelsofbacteriafromtheeƫuentdischarged. Wherethecontaminationistheresultofuntreatedeƫuentdischargesfromcombined sewer overƪows(CSOs)orpoorlyfunctioning(misconnected)sewerageinfrastructure, only increased sewage storage or treatment capacity at the works or investment in infrastructural improvements may be capable of reducing these impacts. This type of remedial work can have signiƤcant cost implications for the individuals or the water companyresponsiblefortheinfrastructure(seebelow). Mitigationmeasuresforreducingmicrobialcontaminationinwatercoursesderivedfrom diơuseagriculturalsourcesinclude:

 Reductioninlivestockstockingrate  Creationofriparianbuơerstrips  Creationofwetlandsorreedbeds  Exclusion of livestock from watercourse and provision of alternative drinking sourcesforlivestock

 Increasedslurrystoragecapacity  Minimisethevolumeofdirtywaterproduced(cleananddirtywaterseparation)  Increaseduseofsolidmanure  DonotapplymanureorslurrytoƤeldsathighǦrisktimes

CDŽSE SƼǟLjY Tȱɏ Cȵeʋɚ SɄȭʑɞ PUʝjecɢ BeforeSouthWestWater(SWW)wasprivatisedin1989,littlehadbeendonetoprotectthecoastalbathingwatersofthe South West, and the region’s reputation was suơering as a result. In 1990, the UK Government adopted higher water quality standards imposed by the European Union, making the need for change even more critical. Starting in 1992, SWW’sresponsetothiswasCleanSweep–thelargestenvironmentalprogrammeofitskindinEurope. Overan18yearperiod,over£1.5billionwasinvestedinimprovingthewater qualityoftheSouthWest’sbathingwaters.AsaresultofCleanSweep,250 crude sewage outfalls were closed and 140 individual mitigation projects werecompleted. Thesuccessoftheprogrammewasdemonstratedin2006,whenfortheƤrst timeall144bathingsitesinSWW’sregionachieved100%compliancewith the EU mandatory standard. This was a massive improvement when comparedtothesituationin1996,whenonly51%ofbeachescomplied. The2007GoodBeachGuide,publishedbytheMarineConservationSociety (MCS), stated that ‘theSouthWestisthetopperformingregioninthisyear’s guide’andrecommendedover80%ofbeachesinSWW’soperatingregion. Since Clean Sweep ended in 2010, SWW have continued to develop their strategic plans for the delivery of environmental improvements and sustainability. Most recently, they have been working in partnership to locateandremediatemisǦconnectionsinTorbay,BudeandPlymouth.

49

Moreinformation:www.beachlive.co.uk

MICROBES&PARASITES

All of these measures act to either reduce the total levels of faecesǦcontaminated materialavailableformobilisationonafarm,changethewaythatmanureisstoredto reduceitslikelihoodofmobilisationtoawatercourse,preventdirect‘voiding’intowater courses, or disconnect the pathways via which faecal material is washed into watercourses.


CDŽSE SƼǟLjY Tʝʁbʋɨ Baʃʕʖng :atʑɠ IʛʠUʝɃʑȷʑnɢ PUʝjecɢ InitiatedandfundedbySouthWestWaterin2010anddeliveredbytheEnvironment Agency working in partnership with Torbay Council, the Torbay Bathing Water Improvement Project aimstoreducethelevelsofpollutioninTorbay'sstreamsand improvebathingwaterquality.Inparticular,theprojecthasfocusedonlocatingand remediatingdrainageandsewagemisǦconnectionsthatareleadingtopollution. TheprojecthasfocusedonƤveresortbeaches,keytothelocaleconomy,whichare atriskoffailingtomeetthenewstandardssetoutbytheRevisedECWaterDirective from 2015. These beaches were Torre Abbey, Hollicombe, Preston, Paignton and Goodrington. MisǦconnections Over one hundred misconnected properties have been identiƤed through the project,whichhaveallbeendischargingfoulordirtywaterintostreamsthrough surface water systems. 80% of the misǦconnections found have now been resolvedandconnectedtofoulsewer. Themajorityofmisconnectionshavebeenresidentialwithhouseholdextensions andwashingmachinesmovedintogaragesbeingthemostcommonculprits. Commercial inputs have also been an issue; including a hotel, car wash, two cafes,asupermarket,doctorssurgery,oƥcesandafactory.Otherissuessuchas dog and bird fouling, waste from boats, sewerage infrastructure and council operationsareallbeinglookedataspartoftheproject. It is estimated that the project has so far stopped approximately 5,000 cubic metres (per annum) of polluting water entering Torbay streams and bathing waters. ExamplesofthemisǦconnectionsfoundinTorbaythatdischargeeitherdirectlyintoa watercourse(topleft)orintoasurfacewatersewer(bottomleft).

MICROBES&PARASITES

Working with the hotel owners and South West Water, the issue was identiƤed and resolved with a considerable improvementinwaterqualityinthestream,asshowninthe chart(right). Inotherlocationssixhouseswerefounddischargingintothe TorreAbbeyandCockingtonStreamsandablockedprivate manholewasallowingfoulwaterfromtwoƪatstodischarge totheseaviaanunǦsampledsurfacewatersystem.

120

Problem fixed

100 Cell count (000's /100ml)

SigniƤcantƤndings InoneTorquayhotelablockageinamainfoulsewerlinewas leadingtoconsiderablepollutionoftheCockingtonstream.

80 60

Faecal Coliforms/100ml

40 20 0

Working with Environment Agency contractors (ONSPOT), the project also discovered that a large factory had been wrongly connected and was discharging most of its waste waters into the Torre Abbey Stream via a surface water system.Thefactoryaccommodatessome100staơandisthoughttohavebeenpollutingthestreamforovertenyears. NextSteps Such was success of the Torbay project that additional funding has now been secured and the focus will be extendedtoincludetwofurthercatchmentsinTorbay;the TorreAbbeyStreamandtheKirkhamStream,whichboth remainaơectedbyasyetunknownpollutionsources.

PaigntonBeach

In addition, the project will also produce an engagement plan, designed to advise and educate both the public and tradesmen, to reduce the likelihood of further misǦ connectionsinthefuture.Thereisalsobeadriveunderway to share best practice from the project with other local authoritiestohelpimproveother‘atrisk’bathingwatersin locationssuchasBude(northCornwall)andPlymouth. 50


CDŽSE SƼǟLjY Meaʣureɡ Wɛ ʛiʤiJatɏ ʏɔՕXȿɏ ʛiʎUɼʍiɪl pɼɸʙXʤiʝɚ ʢisk Methods to reducepathogen transfers towatercoursesessentiallytackle aspectsofsource,mobilisationordeliveryto thewatercourse. Perhaps the most eơective measures designed to reduce the sources of faecal and organic material are those that improvethemanagementofmanurebyincreasingslurrystoragecapacity,reduceinputsofrainwatertomanurestores orswitchtoaconƤnedcompostingsystemofstorage. Byreducingthevolumeofcontaminatedmaterialproducedthesemeasuresenablefarmerstorestricttheirapplicationof manuretothelandtodryperiods,whentheriskofwashǦoơisleast.Theyalsoallowfarmerstokeeptheiryardsfreeof contaminatedmaterialandreducethelevelsoflivebacteriainthemanurebeforeitisspread.

Another major source of microbial contaminants is direct ‘voiding’ by livestock while in or immediately adjacent to a watercourse. In a 7 year study ofadairy farm, Line(2003)demonstratedthatlivestockexclusionresultedina66%reductioninthe levelsoffaecalcoliformsinthewatercoursebelowthefarmandthereisconsiderableadditionalevidencethatexclusion of livestock from water courses and the provision of alternative drinking points can signiƤcantly reduce contributions fromthissource(seetablebelow).

Location

BuơerWidth(m)

SoilTexture

Slope(%)

Eƥcacy (%FIOreduction)

Atwilletal.(2002)

USA

3.1

Sandyloam

5Ǧ20

99.9

Limetal.(1998)

USA

6.1

Siltloam

3

100





12.2





100





18.3





100

Muenzetal.(2006)

USA

25

Sandyclayloam

16.5

53

Tateetal.(2004)

USA

1.1

Sandyloam

5Ǧ20

75Ǧ88

Reference

51

MICROBES&PARASITES

The Ƥnal type of intervention that can mitigate delivery of microbial contaminants to watercourse are riparian buơer stripsandconstructedwetlandsthatacttodisconnectpollutionpathwayscarryingmaterialwashedoơthelandsurface. TheabilityofthesemeasurestodisconnectrunǦoơhasalreadybeendescribedindetail,buttherehavebeenanumberof studiesthathaveinvestigatedtheirabilitytoreducebacterialloadsatƤeldandplotscale(summarisedintablebelow).


COLƵ8R , ƼDŽSTE & ODƵ8R CƵǔƸƵǟǕLjS

COLOUR,TASTE&ODOUR

52


COLƵ8R,

ƼDŽSTE

&

ODƵ8R

There are a number of factors that may result in water exhibiting aberrations in its colour, taste or odour and which negatively aơect its quality and/or safety. On most occasionswhencolour,tasteorodourproblemsdooccurtheimpactsareprimarilyon theaestheticqualityofthewaterandtherefore,withtheresultingincreaseintheriskof water customer dissatisfaction, there is an increase in the intensity and cost of treatmentrequiredtoremoveitfromthewater.

Ferric(ironǦbased)compoundsleachin toastream(top)andheavilycoloured waterintheupperreachesoftheRiver Dart(bottom).

Inaddition,however,thereareoccasionswhensolublecolour,tasteandodourcausing compounds occur which can pose a serious threat to the condition of water supply infrastructureand,insomecircumstances,tohumanorecosystemhealth. Perhapsthebestexamplesofthisaremetalionswhich,inadditiontocausingaesthetic problemsinthewater,canhavesigniƤcantimpactsontheecologicalconditionofrivers andstreams.

SʝuUȪeɡ Է cɼOʝuɠ, WaVtɏ & oGʝuɠ cʝʛpʝunGɡ There are two main groups of soluble species that can cause colour, taste and odour problems,namelymetalionsandsolubleorganiccompounds(acomponentofdissolved organiccarbon—DOC).

Solublespecies

Sources

Impacts

Metalions





ǦAluminium

Naturalreleasefromunderlyinggeologyand biǦproductofwatertreatmentcoagulation process.

Cancausediscolourationofwater.Evidencesuggeststhere maybesomehealthandecologicalimpactsofchronicexpoǦ sure.

ǦCopper

Naturallyoccurring,butcanbemobilisedas aresultofhumanactivity.

Cancausemetallictasteandcanleadtothediscolourationof supplyinfrastructure.Evidencesuggeststheremaybesome healthandecologicalimpactsofchronicexposure.

ǦIron

Naturallyoccurring,butcanbemobilisedas aresultofhumanactivity.

Cancausemetallictasteandcanleadtothered/browndiscolǦ ourationofsupplyinfrastructure.Evidencesuggeststheremay besomeecologicalimpactsofchronicexposure.

ǦManganese

Naturallyoccurring,butcanbemobilisedas aresultofhumanactivity.

Cancausemetallictasteandcanleadtotheblack/browndiscolǦ ourationofsupplyinfrastructure.Evidencesuggeststheremay besomeecologicalimpactsofchronicexposure.

ǦZinc

Naturallyoccurring,butcanbemobilisedas aresultofhumanactivity.

Cancausemetallictaste.Evidencesuggeststheremaybesome ecologicalimpactsofchronicexposure.

Organiccompounds





ǦGeosmin

Producedbyaerobicallygrowingaquatic algaeandmicrobes.AlsoproducedbyƤlaǦ mentousactinomycetebacteriainsoil.

Causeearthytasteandodourproblemsindrinkingwaterthat areveryhardtoremovewithoutactivatedcarbonƤltration.

ǦMethylǦIsoborneol (MIB)

Producedbyaerobicallygrowingaquatic algaeandmicrobes.AlsoproducedbyƤlaǦ mentousactinomycetebacteriainsoil.

Causeearthytasteandodourproblemsindrinkingwaterthat areveryhardtoremovewithoutactivatedcarbonƤltration.

ǦTrihalomethanes (THMs)

ProducedasabiǦproductofchlorineǦ disinfectionofdrinkingwatercontaining organicmaterial.

GrowingevidencethatTHMsarecarcinogenic.Veryhardto removewithoutactivatedcarbonƤltration.

ǦHumicsubstances

Producedbybiodegradationofdeadorganic matter(e.g.peat,woodland,algaeetc.)

Discolourationofwater(yellow)thatisveryhardtoremove withoutactivatedcarbonƤltration. Canreduceeƥciencyofothertreatmentprocesses.

53

COLOUR,TASTE&ODOUR

Thesecompounds(describedinthetablebelow)areoftenderivedfromnaturalsources intheenvironment,suchastheunderlyinggeology,orthroughthenaturalbreakdown of organic material. However, in certain circumstances their levels can be artiƤcially elevatedasanindirectresultofhumanactivitiesorasadirectbiǦproductofthewater treatmentprocessitself.


The drainage and overǦexploitation of peat bogs and other upland habitats with peatǦ based soils, is known to enhance the loss of dissolved organic carbon (DOC) to watercoursesandtosigniƤcantlyincreasewaterdiscolourationthroughcontamination with colourǦcausing organic compounds such as humic acids (Worrall et al., 2007; Wallageetal.,2006;Armstrongetal.,2010). Humicacids(top)areknowntobe releasedfromdegradedpeatland (bottom).

In addition to the colourǦcausing compoundsderived from peat and peaty soils, it has alsobeenshownthatleaflitterisanotherimportantsourceofnaturaldissolvedorganic carbon (DOC) in forested catchments (Hongve, 1999). Interestingly, rainwater percolating through fresh litter is known to obtain higher concentrations of DOC and colour than is derived from older forest ƪoor material and organic soils. Furthermore, deciduousleaflitterhasbeenshowntoimparthighDOCconcentrationsintheautumn, whileconiferouslitterandorganicsoilsreleaseDOCmoreevenly. IntheirAdvisoryNote19on,‘Riversandtheircatchments:potentiallydamagingphysical impacts of commercial forestry’, Scottish Natural Heritage warn that ploughing and restructuringofdrainagepatternsmayoccuraspartofgroundpreparationworkpriorto commercialtreeplanting.Theyalsodescribehowdrainageditchesareoftenalignedat rightanglestotheslope,whichcausespeakrunǦoơƪowstoarrivemorerapidlyinthe receivingwatercourse. The eơect of this drainage, coupled with the increased availability of colourǦcausing compoundsinthesoilduetothedecompositionofleaflitterandthedegradationofthe peat,couldbethecauseofthedeteriorationsinwaterqualitynowcommonlyobserved inmanywatercoursesandreservoirsinuplandcatchments.

Datashowinglargeseasonal accumulationsofgeosmin(top)and manganese(bottom)inasmall reservoirintheSouthWestofEngland.

Other organic taste and odourǦcausing compounds that are generated in soil and decomposing organic material are geosmin and 2ǦMethylisoborneol (MIB). These compounds are also generated within many lakes and reservoirs as algal and macrophytegrowthdiesbackattheendsofthegrowingseason(seeright). Many colourǦcausingmetals,suchas iron, zinc and manganese,are releasednaturally fromlandwithunderlyinggeologywheretheyoccurandtheycanthereforebeleached atquitesigniƤcantlevelsintowatercourses.ThisleachingcanbesigniƤcantlyenhanced wheregeologicaldisturbancehasbeencausedthroughhumanactivitiessuchasmining.

COLOUR,TASTE&ODOUR

It has also been shown that upland peaty soils, with their inherently acidic nature, particularly favour the mobilisation of manganese and, furthermore, conifer aơorestation has also been demonstrated to increase manganese levels in surface watersimmediatelyfollowingfelling. In addition to beingcatchmentǦderived,manganeseƪuxin lakesor reservoirscanalso occur as a result of seasonal stratiƤcation occurring in eutrophic waterbodies. ManganeseionsaremobilisedintosolutionfromlakeǦbedsedimentwhenanhypoxic/ anoxic layer of water forms above it and, once solubilised, are then distributed throughoutthewaterbodywhenreǦmixingofthewatercolumnoccursintheautumn. Thisphenomenonresultsinlargespikesofthesemanganeseionsinsolutionatvarious times(seeright)andcanthenpresentasigniƤcantchallengetotheecologicalhealthof theaquaticenvironmentandtothewatertreatmentprocess. 54


IʛpacWɡ Է cɼOʝuɠ, WaVtɏ & oGʝuɠ cʝnWʋʛʖnʋnWɡ Onthehealthofaquaticecosystems The ecological impacts of taste and odourǦcausing organic compounds (dissolved organic carbon) remain poorly understood, but their ecotoxicology has been investigated in a number of experimental systems and few toxic eơects have been demonstratedattheconcentrationstypicallyfoundincontaminatedwaterbodies. In contrast, several metal ions have been shown to have an impact on the ecological healthofaquaticecosystems.AsaresultoftheseƤndingschromium,copper,iron and zinc are all listed as ‘speciƤc pollutants’ and have standards monitored as part of the ecological condition assessments undertaken for the Water Framework Directive classiƤcation process. The inclusion of manganese as a speciƤc pollutant in the next cycleofWaterFrameworkDirectiveclassiƤcationiscurrentlybeingconsidered. Ontheprovisionofdrinkingwater Thelevelsofcolour,tasteandodourcompoundsinrawwaterhaveadirectimpacton the dose of coagulant required in its treatment at the water treatment works (indeed manyworksdosecoagulantaccordingtoturbidityandcolourlevelsintherawwater).If thesecompoundsarenotremovedtheycanimpingeontheaestheticqualityoftheƤnal drinking water and cause the discolouration of drinking water infrastructure (for examplemanganeseintreatedwatercanstainsanitaryware). In addition, soluble organic compounds, such as humic substances and geosmin, can cause further problems at the water treatment works as they can be converted into disinfection byǦproducts (DBPs) when chlorine is used duringwater treatment process (Krasneretal.,1989). TheseDBPscantaketheformoftrihalomethanes(THMs),haloaceticacids(HAAs)and ahostofotherhalogenatedDBPs,manyofwhichhavebeenshowntocausecancerin laboratory animals and which can pass though the standard treatment processes undertakenatmanyworks(Singer,1999;Rodriguezetal.,2000).

CDŽSE SƼǟLjY Increasing levels of colour in the water from Fernworthy Reservoir on the eastern edge of Dartmoor represent a signiƤcant challenge for South West WaterattheTottifordwatertreatmentworks.Thedeteriorationinthewater qualityinthereservoirwassoseverethattheBoveyCrosswaterworkshadto closebecausethetreatmentprocesscouldnotcopewiththerawwater.The colourǦcausing compounds in Fernworthy Reservoir are primarily humic substancesderivedfromthedegradationoforganicmaterialinthepeatǦlands andforestedareasthatsurroundthismoorlandreservoir(seelandcovermap; right).ItisclearthatwaterpercolatingthroughpeatorforestleafǦlitteracross thecatchmentismobilisingandtransportingthesecolourǦcausingsubstances into the watercourses and drains that feed into the reservoir. This eơect is being signiƤcantly enhanced in areas where the peat has been damaged or degradedthroughdrainageorintensiveexploitation. HumiccolourǦcausingcompoundsinrawwatercanonlybe removedthroughthecoagulationprocessattheworksand so, if the colour levels in the water increase, it can have signiƤcantcostimplicationsforthewatercompanyasthe coagulant dose must also be increased. These organic compounds cause further problems at the works as they can be converted into disinfection byǦproducts (DBPs) whenchlorineisusedduringwatertreatment. Examination of South West Water data (left) shows that the level of colour in Fernworthy Reservoir cycles throughout the year, but also that the average level has signiƤcantlyincreasedsince2004.

55

COLOUR,TASTE&ODOUR

CɼOʝuɠ ʖɚ FʑʢʜwɛԬʕɨ ReȿʑʢYʝʖɠ, 'ʑYʝɚ


Peatlandrestorationbeingundertaken bytheExmoorMiresProject(top)and stakeholdersvisitarestoredmiressite (bottom)

CɼOʝuɠ, WaVtɏ & oGʝuɠ ʛiʤiJaʤiʝɚ ȷeaʣureɡ Ultimately, the only way to completely remove the soluble organic compounds and metal ions that cause colour, taste and odour problems in raw water intended for treatmentandsupplyasdrinkingwateristoimplementtechnologicalsolutions,suchas activatedcarbonƤlters,atthetreatmentworks. Whethertheyarederivedfrompointordiơusesourcesinthecatchment,mitigationof theirlossintotheaquaticenvironmentattheirsourceisfarmorechallengingtoachieve. Havingsaidthis,however,thereisincreasingevidencethatreǦwettingofpeatǦlandsand miresthathavebeendegradedbydrainageoroverǦexploitationofpeatcanreducethe leaching of Dissolved Organic Carbon (DOC) compounds that cause colour, taste and odourcontaminationofrawwater. SpeciƤcally,severalstudieshavedemonstratedthatthereǦwettingofmiresandpeatǦ lands, through the practice of drainǦblocking, can signiƤcantlyreduce the lossof DOC andcolourǦcausingcompoundsfromlandofthistype(Wallageetal.,2006;Armstrong etal.,2010). IntheirextensiveUKǦwidesurveyofblockedandunblockeddrainsacross32studysites andthroughtheintensivemonitoringofapeatdrainsystemthathasbeenblockedfor7 years, Armstrong et al. (2010) demonstrated that dissolved organic carbon concentrations and water discolouration were signiƤcantly (~28%) lower in blocked drainscomparedtounblockeddrains. Overall,whetherthesourceofcontaminationisfrommineworks,forestryorpeatland soilsitisclearthatitisthemanagementofdrainageandthehydrologicalregimeofthe landwhichmayachievethegreatesteơectinmitigatingtheimpactsofcolour,tasteand odourǦcausingcontaminants.

CDŽSE SƼǟLjY Tȱɏ SXVWʋʖnɪɬȵɏ CaWɭʕȷʑnɢ MʋnaȰʑȷʑnɢ PUoʔUʋʛȷɏ (SCɈǔP) The Sustainable Catchment Management Programme (SCaMP), has been developed by United Utilities in association with the Royal Society for the Protection of Birds (RSPB). Theprogrammeaimstoapplyanintegratedapproachtocatchmentmanagementacross allofthe56,385hectaresoflandUnitedUtilitiesownintheNorthWest,whichtheyholdto protectthequalityofwaterenteringthereservoirs. ThroughthedeliveryofSCaMPUnitedUtilitiesisrecognisedwithintheUKwaterindustry asbeingattheforefrontofwatercompanyǦfundedcatchmentmanagementschemethat areaimingtosecuremultiplebeneƤtsatalandscapescale. Overthelast30yearstherehasbeenasubstantialincreaseinthelevelsofcolourinthewatersourcespriortotreatment frommanyuplandcatchments(seeexamplebelow).Theremovalofcolourrequiresadditionalprocessplant,chemicals, powerandwastehandlingtomeetincreasinglydemandingdrinkingwaterqualitystandards.Toaddressthis,expensive capitalsolutionsareoftenrequiredatawaterworkswhichresultinsigniƤcantincreasesinannualoperationalcosts.

COLOUR,TASTE&ODOUR

TheaimsoftheSCaMPinitiativearetohelp;(1)protectand improvewaterquality,(2)reducetherateofincreaseinraw water colour which will reduce future revenue costs, (3) reduce or delay the need for future capital investment for additional water treatment, (4) deliver government targets for SSSIs, (5) ensure a sustainable future for the company's agricultural tenants, (6) enhance and protect the natural environment, and (7) help these moorland habitats to becomemoreresilienttolongtermclimatechange. MonitoringatasubǦcatchmentlevelinSCaMPdeliveryareasindicatesthatthereisastatistical‘tippingpoint’twoyears afterintervention.ThishasbeenfoundinsimilarshorttermstudiesanditisthoughtthatreǦwettingdriedpeatinitially releasesmorecarbonintheformofcolourbeforethenaturalbiochemicalprocessesbegintoreǦestablish.Atpresent several subǦcatchments are indicating a slight, but statistically signiƤcant, decrease in colour over time and one site hasseenasigniƤcant45%reductioninstreamƪowturbiditysincerestoration. Formoreinformationvisit—corporate.unitedutilities.com/scampǦindex.aspx 56


DŽǜSNJǜƻǏǕ* ƮǔPƺ2VƩMNJNǝS ǏN WATER QUDŽLIǝ Y

57


AǜSNJǜƻǏǕ* IǔPƺ2VƩMNJNǝS Theprincipal,overǦarchingaimofanycatchmentmanagementworkistoimprovethe water quality in our freshwater ecosystems and to make a signiƤcant contribution to their attainment of good ecological status in accordance with requirements of the EU WaterFrameworkDirective.It isthereforevital thatsuƥcient evidence iscollected to provideanobjectiveandrobustassessmentoftheimprovementsdelivered. Ultimately, we must be able to justify that the money spent and the interventions deliveredacrossthelandscapehavedeliveredsigniƤcantimprovementsinwaterquality (and have therefore made signiƤcant contributions to the delivery of good ecological status of river catchments) and have generated signiƤcant secondary Ƥnancial, ecologicalandsocialbeneƤts. To achieve these overǦarchingaims, a range of approaches have been developed that willallowustoassessvariousoutcomesdeliveredbyourcatchmentmanagementwork;

 QuantiƤcationof interventiondelivery. Gatheringpreciseanddetailedevidenceof whathasbeendelivered,whereandhowitwasdelivered,whatitcostand,perhaps mostimportantly,whattheintendedoutcomewasforeachmeasure.

 Monitoring forenvironmentaloutcomes. Collectionofacomprehensiveandrobust set of data and evidence which demonstrates qualitatively and quantitatively whetherrealimprovementsinrawwaterqualityhavebeenachieved.Toachievethis it is vital that this includes robust baseline data that includes temporal (before intervention)andspatial(nointervention)controls.

 Modellingtopredictenvironmentaloutcomes.Useofthemostadvancedmodelling techniques which can be used to estimate the improvements in water quality that havebeenachieved.

 Assessment of secondary outcomes. There are a number of monitoring and modelling approaches that can be used to assess how a catchment management programme has enhanced the provision of other ecosystem services across a catchmentandtoquantifytheeconomicbeneƤtstothoseengagedintheprocess.

CDŽSE SƼǟLjY Tȱɏ 'EFƺA 'ʑPʝnVʤUaʤiʝɚ TeVɢ CaWɭʕȷʑnWɡ ('TC) AspartofanationaldrivetogatherevidencethatcatchmentmanagementcanhaveasigniƤcantimpactonrawwater qualityDEFRAarecurrentlyfundinga£5millionDemonstrationTestCatchment(DTC)Projectacrossthreecatchments: the HampshireAvon, theWensumandthe Eden. The aimofDTCProjectsis toevaluatethe eơectiveness ofonǦfarm measurestoimprovewaterqualitywhentheirdeliveryisscaledǦuptoarealǦlifewholesubǦcatchmentsituation.. The Westcountry Rivers Trust’s current Upstream Thinking Project on the Caudworthy Water, a short (~3.5 km) tributaryoftheRiverOtteryintheTamarcatchment,nowrepresentsasatellitestudyoftheHampshireAvonDTC.The DTC consortium is undertaking a detailed monitoring programme before and after the a comprehensive farm investmentandadviceprogrammebeingdeliveredacrossthecatchment. Twomonitoringstationslocatedatthemiddleandbottomofthecatchmenthave been recording total nitrogen, nitrate, nitrite, soluble reactive phosphate, total phosphate, turbidity, suspended sediment concentration, dissolved oxygen, temperature,pH,ammonium,chlorophyll,eơectiveparticlesizeanddischarge. In addition to this chemical monitoring programme, extensive biological monitoringhasalsobeenundertakeninthecatchment,includingtheassessment ofmacroǦinvertebrates,benthicalgae(diatoms),macrophytesandƤsh. The baseline data for Caudworthy Water has been collected over an 18 month period and Westcountry Rivers Trust have approached all twentyǦfour farmers in theCaudworthyWatersubǦcatchment.Todate,over£450,000hasbeeninvested inaround£700,000worthofcapitalinvestmentswithBestManagementPractices ensuredthroughtheapplicationofaRestrictiveDeedon19ofthesefarms. Following the implementation of the Best Management Practices in 2012Ǧ13, the eơectsonwaterqualitywillthenbemonitoredover2013Ǧ15.

58


CDŽSE SƼǟLjY Tȱɏ E[tʑndeɍ Eʩpɛԭ Cȹeɑ£ʎȲʑnɢ Modɰl (EȉM+) The Extended Nutrient Export Coeƥcient Model (ECM+) has been developedbytheUniversityofEastAngliaundertheRuralEconomyand LandUse(RELU)ProgrammeandpartǦfundedbytheWestcountryRivers Trust. This model has been reviewed by scientiƤc peers and the DEFRA WaterPolicyGroupandiswidelyexpectedtobecomeoneoftheprimary methods for rural land management planning through stakeholder participationinthefuture. ECM+ has been developed to predict the eơects implementation of Best Management Practices (BMP’s) (Cuttle et al. 2007) will have on sediment, faecal indicator organisms (FIOs), phosphorus and nitrogen inputs into watercourses. Put simply, the model uses export coeƥcients for diơerent landǦuse types to calculateexportsofthesepollutantsbasedonthefollowinginputdata:

 Landuse distribution—including urban and various agricultural landuses suchascereals,maizeandgrassland.

 Livestocknumbers—includingnumbersofcattle,sheep,pigsandpoultry.  Population served, treatment levels and locations of Sewage Treatment Works(STWs)

 PopulationnotservedbySTWs—indicativeofseptictanknumbers  Roadandtrackdensity  Rainfall and hydrological data combined with information on inǦstream processingofpollutants

 Locationandareaoflakesandreservoirswithmodelledimpactonpollutant loadatoutƪow

 Farming practices: current uptake of Best Management Practices and eơectivenessinreducingpollutantexport What makes the ECM+ model such a powerful tool is that it is constructed with the participation of farmers, water companyrepresentativesandotherstakeholdersinthecatchmentandthisallowsalloftheinputdatatobe‘groundǦ truthed’beforeitisaddedintothemodel.Inaddition,themodeliscalibratedatthesubǦcatchmentlevelwithrealǦworld, inǦstreammeasurementsofpollutantloadderivedfromEnvironmentAgencymonitoringdata. AnotherimportantcomponentoftheECM+modelisthat,onceithasbeenbuilt,itisthenpossibletodevelopandruna numberofscenarioswiththestakeholders(whichcanincludediơerentblendsofbothBestManagementPracticeson farms and improved sewage treatment measures) and observe their eơects on the export of pollutants to the watercourse. ECM+inAction The River Tamar is a key raw water source for South West Water and has been thesubjectof considerableinvestmentincatchment management interventions through schemes such as Upstream ThinkingandCatchmentSensitiveFarming. The Caudworthy Water subǦcatchment of the River Ottery in the Tamar catchment is also a satellite study site for the DEFRA Demonstration Test Catchment (DTC) project on the Hampshire Avon. Inlightofitsimportanceasadrinkingwatercatchmentandforthe Water Framework Directive (the Crownhill WTWs catchment is comprisedof45WFDwaterbodies)theECM+modelhasbeenbuilt for the River Tamar catchment above its tidal limit at Gunnislake throughaparticipatorydevelopmentprocess. Once built, the model has then be used to predict the improvements in water quality that may have been achieved throughthedeliveryofdiơerentcatchmentmanagementscenariosindiơerentlocations.

59


ExtendedExportCoeƥcientModel(ECM+)...continued….

ThiscasestudysummarisestheECM+predictedexportofnitrateandphosphatefromtheTamarcatchmentunderfour diơerentmanagementscenarios,involvingdiơerentlevelsofimplementationofthetop35(mostcommonlyused)Best ManagementPractices.Thefourscenarioswereasfollows: Scenario1:Baseline(currentsituation,noadditionalinterventions) Scenario2:100%uptakeoftop35BMPsintheCaudworthysubǦcatchment Scenario3:100%uptakeoftop35BMPsacrossthewholeoftheTamaraboveGunnislakeBridge Scenario4:100%uptakeoftop35BMPsacrossthewholeoftheTamarplus90%nitrogenandphosphatestripping eƥciencyatallSewageTreatmentWorks. ThemodeloutputsshowthepredictedaverageconcentrationofeachpollutantagainstspeciƤcstandards.Forphosphate,thebackground matchestheclassiƤcationusedfortheEUWaterFrameworkDirective:bluerepresents‘highecologicalstatus’;green‘goodecologicalstatus’, yellow‘moderateecologicalstatus’,orange‘poorecologicalstatus’andred‘badecologicalstatus’.Fornitrate,thepreǦabstractionstandard fordrinkingwaterisdeƤnedbythedarkblueverticallineonthefarrightofthenitrogenexportgraphsbelow(equatingto11.3mg/l).The brightbluelineinthecentreofthegraphsrepresentsastringentecologicallimitusedinsomewaterbodies,whichtranslatesto2.5mg/l.

Scenario1:Baseline The outputs from the ECM+ model (right) indicate that the Caudworthy subǦcatchment under the current ‘businessǦasǦ usual’ scenario (Scenario 1) is likely to have an average phosphorous export load corresponding to moderate/poor ecologicalstatus. At Gunnislake Bridge the phosphate levels are likely to be moderate. Below the Caudworthy outƪow and Gunnislake Bridge the nitrogen levels are likely to be compliant with the drinking water standard, but exceed the ecological standard in both locations.

Scenario2:100%BMPuptakeontheCaudworthy InScenario2(notshown),themodelpredictsthataveragewaterqualityintheCaudworthysubǦcatchmentwillimprove tobetterthangoodecologicalstatusforphosphateandwillbecompliantwiththemorestringentecologicalstandardfor nitrogen.TheeơectofthislevelofactionintheCaudworthyisalsopassedontoGunnislake,buttheimprovementsare maskedbythevolumeofwaterfromtherestoftheTamarcatchment.

Scenario3:100%BMPuptakeonthewholeTamarcatchment In Scenario 3 (left), water quality at the Caudworthy Water outƪow and Gunnislake Bridge both improve signiƤcantly with nitrogen levels at both sample sites predicted to be compliant withthestringentecologicalstandard. However,phosphatelevelsatGunnislakeBridgearestillonly25% certaintoreachgoodecologicalstatus.

Scenario4:Scenario3plus90%NandPstrippingatSTWs In Scenario 4, the model predicts a greater than 50% chance that the water quality at the Caudworthy outƪow and Gunnislake Bridge would both meet water framework directive standards for phosphorous and that nitrogen levels wouldbecompliantwithstringentecologicalstandards. ECM+predictssigniƤcantimprovementsinwaterqualityasaresultofimplementationofBMP’s.Importantly,theECM+ has been used very successfully as a method for rural land management planning through stakeholder participation. Deliveringimprovementsinwaterqualitythroughcatchmentmanagementrequiresstrongpartnershipsandsuccessful stakeholderengagement,includingprivate,publicandthirdsectororganisationsandlandowners. 60


CDŽSE SƼǟLjY FʋʢPVcʝȼʑɠ ʝɚ ʃȱɏ Hʋʛpsʕʖrɏ AYʝɚ TheFARMSCaleOptimisationofPollutantEmissionReductions(FARMSCOPER) model is a decision support tool that can be used to assess diơuse agricultural pollutantloadsonafarmandquantifytheimpactsoffarmpollutioncontroloptions onthesepollutants. FARMSCOPER allows for the creation of unique farming systems, based on combinations of livestock, cropping and manure management practices. The pollutantlossesandimpactsofmitigationcanthenbeassessedforthesefarming systems. The eơect of a potential mitigation methods are expressed as a percentage reductioninthepollutantlossfromspeciƤcsources,areasorpathways. Thetoolutilisesanumberofexistingmodelsincluding:

 PhosphorusandSedimentYieldCharacterisationinCatchments(PSYCHIC)  NationalEnvironmentAgriculturalPollutionǦNitrate(NEAPǦN)  NationalAmmoniaReductionStrategyEvaluationSystem(NARSES)  MANureNitrogenEvaluationRoutine(MANNER)  IPPCmethodologyformethaneandnitrousoxide. The eơectiveness of mitigation methods are characterised as a percentage reduction against the pollutant loss from a set of loss coordinates. The eơectiveness values were based on a number of existing literature reviews, Ƥeld data and expert judgement and are assumed to incorporate any eƥciencies of implementation. The eơectiveness values for mitigation methods were allowed to take negative values, which can represent ‘pollution swapping’, where a reduction in one pollutantisassociatedwithanincreaseinanother. The tool also estimates potential consequences of mitigation implementation on biodiversity,wateruseandenergyuse. TheHampshireAvonStudy The Hampshire Avon is a lowland system situated on the southern coast of England. It is a predominantly rural catchment with approximately 75% of land used for agriculture. Parts of the Avon suơer from ‘chalk stream malaise’ due to nutrient and sedimentation issues that are thought to primarily originate from diơuse agricultural pollution.Over50%ofthewaterbodiesinthecatchmentdo not achieve good ecological status under the Water FrameworkDirective. TheHampshireAvonisalsooneofDEFRA’sDemonstration TestCatchments.

trekker308

SpatialdatasetsandtheAgriculturalCensusreturnsfortheRiverAvonin2009wereusedtodevelopacollectionoffarm types characteristic of the Hampshire Avon and reƪective of landuse patterns, physical landscape characteristics and farmmanagementpracticesinthearea. Oftheserepresentativefarms,itwasestimatedthattherewere292cerealfarms(representing51%ofthelandarea), 129lowlandgrazingfarms(11%oflandarea),130mixedfarms(20%oflandarea),77dairyfarms(8%oflandarea)and52 horticulturalfarms(lessthan1%oflandarea)intheAvoncatchment.Theremaininglandareacomprisedsmallnumbers ofgeneralcropping,pig,poultryor‘other’representativefarmtypes. FARMSCOPERwasthenusedtotestthreediơerentscenariosandestimatesediment,nitrate,phosphorous,ammonia, methaneandnitrousoxideloadsoremissionsforeachrepresentativefarmtype.Thescenariostestedwere:

 Scenario1:Baselinepollutantemissionswithnomitigationmeasures  Scenario2:Currentpollutantemissionsbasedonanestimateoftheexistinglevelofmitigationmeasures implemented

 Scenario3:MaximumreductionsthroughimplementationofallmeasuresintheDefraUserGuide(Newelletal.2011) 61


FARMCOPERontheHampshireAvon...continued….

Results FARMSCOPERpredictsbaselinepollutantloadingsinkgperhectareperyear(kghaǦ1yrǦ1)(seetable).Underscenario1, thebaselinelevelsofpollutantemissionsifnomitigationmeasurewereinplace,itestimatedthatcerealfarmswould contribute about 55% of nitrate, 38% of phosphorous, 67% of sediment and 50% of nitrous oxide. Mixed farms were estimatedtocontribute48%ofammonia,40%ofmethaneandabout26%ofnitrate,phosphorousandnitrousoxide. The principal contribution from dairy farms was methane emissions, contributing 32% of total methane. These predictionswerecomparedwithmonitoreddataforpollutantloadsintheAvonandwereconsideredacceptable. FarmType

Nitrate(NO3)

Phosphorous

Sediment

Ammonia (NH3)

Methane (CH4)

Nitrousoxide (N2O) 7

Cereals

38

0.2

159

7

0

Generalcropping

37

0.1

117

7

0

7

Horticulture

34

0.3

247

5

0

4

Dairy

40

0.5

104

36

173

10

Lowlandgrazing

24

0.4

80

15

98

7

Mixed

51

0.4

95

43

90

10

Forimprovementscenarios,FARMSCOPERpredictspercentagereductioninemissions(relativetothebaselinescenario) (see table). Under scenario 2, the current pollutant emissionsbased on an estimate of the existing level of mitigation measuresimplemented,theestimatedpercentagereductionsinpollutantemissionsrangedfrom0to15.2%. FarmType

Nitrate(NO3)

Phosphorous

Sediment

Ammonia (NH3)

Methane (CH4)

Nitrousoxide (N2O)

Cereals

4.0%

6.0%

7.8%

9.0%

0.0%

6.2%

Generalcropping

3.9%

6.0%

7.8%

9.0%

0.0%

6.1%

Horticulture

4.5%

6.5%

8.9%

9.0%

0.0%

7.7%

Dairy

4.9%

11.6%

4.9%

15.2%

10.4%

7.6%

Lowlandgrazing

2.4%

10.4%

4.7%

0.3%

0.0%

3.0%

Mixed

3.0%

14.8%

6.3%

4.8%

0.3%

5.4%

Phosphorous

Sediment

Ammonia (NH3)

Methane (CH4)

Nitrousoxide (N2O)

Under scenario 3, which is the delivery of the maximumreductionsthroughimplementationofall mitigationmeasureslistedintheDefraInventoryof MethodstoControlDiơuseWaterPollution(Newell etal.2011),theestimatedpercentagereductionsin emissionsforspeciƤcpollutantsweremuchgreater, rangingfrom0to70.8%. FarmType

Nitrate(NO3)

Cereals

4.0%

6.0%

7.8%

9.0%

0.0%

6.2%

Generalcropping

3.9%

6.0%

7.8%

9.0%

0.0%

6.1%

Horticulture

4.5%

6.5%

8.9%

9.0%

0.0%

7.7%

Dairy

4.9%

11.6%

4.9%

15.2%

10.4%

7.6%

Lowlandgrazing

2.4%

10.4%

4.7%

0.3%

0.0%

3.0%

Mixed

3.0%

14.8%

6.3%

4.8%

0.3%

5.4%

FARMSCOPERalsoallowsthetotalemissionsforeachpollutantinkgperhectareperyear(kghaǦ1yrǦ1)resultingfrom scenarios2and3tobecompared(seebelow). FarmType

Nitrate(NO3)

Phosphorous

Sediment

Ammonia (NH3)

Methane (CH4)

Nitrousoxide (N2O) 6.2%

Cereals

4.0%

6.0%

7.8%

9.0%

0.0%

Lowlandgrazing

2.4%

10.4%

4.7%

0.3%

0.0%

3.0%

Mixed

3.0%

14.8%

6.3%

4.8%

0.3%

5.4%

Conclusion FARMSCOPERestimatedthatcurrentlevelsofmitigationmeasureimplementationhavereducedtotalpollutantloads bybetween3and10%,ascomparedtoascenariowherenomitigationmeasureswereinplace.Italsopredictedthat, shouldtherebesigniƤcantuptakeofthefullrangeofmitigationmeasures,pollutantloadscouldbereducedfurtherby signiƤcantamountsforsediment(66%),phosphorous(47%),nitrate(22%),ammonia(30%)andnitrousoxide(16%). Casestudyadaptedfrom:Zhangetal.,2012

62


SecʝnGʋʢɨ ȩʑȸɏ£Wɡ Է caWɭʕȷʑnɢ PʋnaȰʑȷʑnɢ It is widely accepted that the delivery of catchment management interventions will produceawidearrayofancillarybeneƤtsthatcouldmakeconsiderablecontributionsto improving the ecological condition of rivers and towards other economic, environmentalornatureconservationtargets. SecondaryenvironmentalbeneƤts In addition to determining the primary beneƤt obtained through catchment management interventions, it is also important for any secondary environmental beneƤtsachievedtoberecordedandquantiƤed. This can be undertaken using a number of survey, monitoring and modelling approaches that assess how an intervention can enhance the provision of other ecosystemservicesacrossacatchmentandtoquantifytheeconomicgainsachievedby allofthegroupsengagedintheprocess. Perhaps the most common example of this occurring is where interventions, such as wetlandcreationorrestoration,whichhavebeendesignedandtargetedtoenhancethe regulationofwaterqualityalsoplayakeyroleintheregulationofwaterquantity(high andlowƪows).Itisclearthatthesemeasures,iftargetedintomultifunctionalareasof land that regulate several diơerent ecosystem services, are capable of enhancing the provisionofseveralofthem. In addition, considerable research is also being undertaken to asses the ability of catchment management interventions to restore ecosystem health, deliver increased biodiversityandforthemtothereforehavesigniƤcantconservationvalue.Inonesuch study, undertaken by Jobin etal(2003) in Canada, it has been demonstrated that the creationofriparianbuơerstrips(especiallywoodedones)cansigniƤcantlyincreasethe overallspeciesrichnessandinsectivorousbirdabundanceacrossacatchment. ManyoftheonǦfarmmeasuresdescribedinthisreviewhavealsobeenshowntoreduce theemissionofgreenhousegasesfromagriculturallandandthereisgrowingevidence that many may act to increase their sequestration. Careful targeting of catchment managementmeasurestolandareaswiththegreatestcarbonsequestrationpotential willoptimisethelevelsofsequestrationachieved.

Abrowntroutfromahealthyriver

At a more strategic level, several groups and organisations (such as Durham Wildlife Trust,theWestcountryRiversTrust,andmanyothers)havedevelopedmethodologies forthemappingoflandwhichcontributestotheprovisionofecosystemservices.When combinedtogether,thesestudiesrevealthattherearemanymultiǦfunctionalareasthat playakeyroleinthedeliveryofseveralecosystemservices. These ecosystem services mapping exercises allow us to identify sections of the catchmentwherethesemultifunctional,ecosystemservicesǦprovidingareasmaycome intodirectconƪict,andthereforebe compromisedby,other humanactivities,suchas intensiveagricultureorurbandevelopment. This soǦcalled ‘ecosystem services’ approach allows us to identify where  catchment management or policy level interventions designed to improve the provision of one ecosystem service (e.g. water quality) may also yield concurrent improvements in the provisionofotherecosystemservices.Ultimately,thisapproachallowsinterventionsto be delivered in a targeted, integrated and balanced way that delivers the greatest environmentalimprovementfortheresourcesavailable. 63


AssessmentofƤnancialcostsandbeneƤts For the full beneƤt of catchment management interventions to be assessed, it is also importantforallofthepartiesinvolved(funders,deliverers,beneƤciaries,landowners) to have a clear understanding of the Ƥnancial costs and beneƤts of the proposed change. For many interventions, a clear and detailed understanding of their cost of deliveryhasalreadybeengainedand,aswehavedescribedpreviously,theevidencefor theirenvironmentalbeneƤtcontinuestobegathered. Thekeylinkthatwillneedtobeestablished,oncethisevidenceisinplace,ishowthe environmentalbeneƤtsachievedcanbetranslatedintoƤnancialbeneƤtsforthefunder, thebeneƤciariesoftheecosystemserviceorthelandmanagerswhohaveimplemented theintervention(e.g.astheresultofincreasedeƥciencyorreducedcostsincurred). This information will then allow the costǦbeneƤt of catchment management interventionstobeexploredinmoredetail.Atpresent,therobustextrapolationofthe costǦbeneƤt ratios calculated up to the subǦcatchment or catchment scale remains a signiƤcantchallengethatwillrequirecarefulconsiderationandfurtherresearch.

CDŽSE SƼǟLjY PʋʪȷʑnWɡ fʝɠ EcoʣyVtʑm SʑʢviȪeɡ (PNJS) Payments for Ecosystem Services (PES) schemes are marketǦbased instruments that connect ’sellers’ of ecosystem serviceswith‘buyers’.ThetermPaymentsforEcosystemServicesisoftenusedtodescribeavarietyofschemesinwhich the beneƤciaries of ecosystem services provide payment to the stewards of those services. Payments for Ecosystem Servicesschemesincludethosethatinvolveacontinuingseriesofpaymentstolandorothernaturalresourcemanagers inreturnforaguaranteedoranticipatedƪowofecosystemservices. At present, farmers, who represent less than 1% of our society, currently manage ~80% of our countryside and are largelyresponsibleforthehealthoftheecosystemsitsupports.However,despitethiskeyroleforfarmersinmanaging ournaturalecosystems,theyarecurrentlyonly paid fortheprovisionof oneecosystem service;foodproduction.The ideabehindPaymentsforEcosystemServicesisthatthosewhoareresponsiblefortheprovisionofecosystemservices shouldberewardedfordoingso,representingamechanismtobringhistoricallyundervaluedservicesintotheeconomy. A Payments for Ecosystem Services scheme can be deƤned as a voluntary transaction where (1) a wellǦdeƤned ecosystem service (or a landǦuse likely to secure that service) is being ‘bought’ by (2) an ecosystem service buyer (minimum of one) from (3) an ecosystem service seller (minimum of one) if, and only if, (4) the ecosystem service providersecuresecosystemserviceprovision(conditionality). AnexampleofaPESscheme:UpstreamThinking Drinkingwaterisavitalecosystemservicethatwederivefrom ourrivercatchmentsandthereissigniƤcantscopefor watercompaniesinterestedinthequalityoftherawwatertheytreatforsupplytocustomersasdrinkingwater. SouthWestWater’sCrownhillwatertreatmentworksinPlymouthcurrentlytreatsaround55Ǧ60millionlitresofwater each day and it is anticipated that over the next 20 years the demand for water in Plymouth will increase steadily towards100millionlitresaday.Inadditiontothisincreaseddemandforwater,thereisevidencethatdecliningwater qualityintheriversourcesusedtosupplytheCrownhillworkscouldconcurrentlyincreasethecostsandrisksassociated withthetreatmentoftherawwaterundertakenthere. The South West Water Upstream thinking project is a PES scheme in which the water company invests in catchment management on behalf of their customers in an attempt to avoid incurring the extra costs and risks associated with treating low quality raw water at the works. If the average cost of treating water at Crownhill is increased by £5 per millionlitrestreated(~10%)duetopoorrawwaterqualitythentheremovalofthispressurecouldsaveover£2millionon treatmentcostsoverthenext20years(atatreatmentvolumeof60millionlitresaday). Under the current situation, where land is managed exclusively for agricultural production, only the private proƤts from this activity are realised. By identifying where anotherecosystemservice,suchasimprovedwaterquality, maybeprovidedandbyoơeringeitheraminimumpayment to cover proƤt forgone or a maximum possible payment based on the overall value to society, the buyer can incentivise the seller to change, or even switch, their practice and therefore deliver the improvements in the ecosystemservicetheyrequire. 64


G2VEǛƴDŽNǨE & STƺATNJGIC ǙLDŽǕƴǏǕ*

65


Overall(top)andƤsh(bottom)statusof waterbodiesintheTamarcatchment undertheWaterFrameworkDirective classiƤcationsystem.

*2VEǛƴDŽNǨE & PLDŽǕƴǏǕ* Tȱɏ EC :atʑɠ FUʋȷʑwʝʁk 'ʖrecʤʖɃɏ 200 Perhaps the greatest driver for catchment management is the requirement for the conditionofUKriverwaterbodiestomeetthequalitystandardssetoutintheEuropean Commission Water Framework Directive 2000 (WFD, 2000). The WFD assessment process, which applies to lakes, rivers, transitional and coastal waters, artiƤcial and heavily modiƤed waterbodies, and groundwater, has set more rigorous and higher evaluationstandardsforthequalityofouraquaticecosystems. The main objectives of the WFD are to prevent deterioration of the status of waterǦ bodies, and to protect, enhance and restore them with the aim of achieving ‘good ecological status’, or ‘good ecological potential’ in the case of heavily modiƤed waterbodies. Similarly, groundwater bodies need to reach a good status as they are required to maintain drinking water quality. The WFD aims to achieve at least good statusforallwaterbodiesby2015or,ifcertainexemptioncriteriaaremet,thenbyan extendeddeadlineof2027. TheWaterFrameworkDirectivedeliveryprocessessentiallyoccursinthreephases:(1) waterbodyconditionassessmenttocharacteriseecologicalstatus,(2)investigationsto diagnose the causes of degradation, and (3) a programme of remedial catchment managementinterventionssetoutinaRiverBasinManagementPlan(RBMP). Inadditiontoprotectingandimprovingtheecologicalconditionofaquaticecosystems, theWaterFrameworkDirectivehasseveralfurtheroverarchingaimsthatinclude;

 Promotingsustainableuseofwaterasanaturalresource  Conservinghabitatsandspeciesthatdependdirectlyonwater  Contributingtomitigatingtheeơectsofƪoodsanddroughts

Tȱɏ caWɭʕȷʑnɢ pɈԯȸʑUsʕʖɞ ʋpʠUoaɭh In recent years it has been increasingly recognised that enhancing the delivery of ecosystem services through better catchment management should not only be the responsibilityofthepublicsector,butalsotheprivateandthirdsectors. Alongside this movement towards shared responsibility, there is also now a growing bodyofevidencethatfargreaterenvironmentalimprovementscanbeachievedifallof the groups actively involved in regulation, land management, scientiƤc research or wildlifeconservationinacatchmentareaaredrawntogetherwithlandownersandother interestgroupstoformacatchmentmanagementpartnership. Anumberofresearchprojectshavenowbeenabletodemonstratethatanempowered catchmentareapartnershipcomprisedofdiversestakeholdersandtechnicalspecialists from in and around a catchment, can be responsible for coordinating the planning, funding and delivery of good ecological health for that river and its catchment. They have also shown us that an integrated stakeholderǦdriven assessment of a catchment will we be enable us to develop a comprehensive understanding of the challenges we faceand,followingthis,todevelopastrategic,targeted,balancedandthereforecostǦ eơectivecatchmentmanagementinterventionplan. 66


CDŽSE SƼǟLjY RuUɪl Ecʝnʝʛɨ & /ʋnɍ 8ȿɏ (RNJL8) PUoʔUʋʛȷɏ The interdisciplinary RELU Programme, funded between 2004 and 2011, had the aimofharnessingthesciencestohelpandpromotesustainableruraldevelopment and advance understanding of the challenges caused by this change today and in thefuture.Researchwasundertakentoinformpolicyandpracticewithchoiceson howtomanagethecountrysideandruraleconomies. TheƤndingsofseveralRELUprojectshighlightedtheneedformoresustainedand twoǦway communication with stakeholders about land management. The researchershavedemonstratedthatnew‘knowledgeǦbases’canbeestablishedthat combinelocalknowledgewithexternalexpertise. TheresearchhasalsoidentiƤedanumberoftechniquesthatenablestakeholders, who may start with diơerent views and levels of understanding, to redeƤne the issues collectively in a way that can help them Ƥnd innovative solutions with multiplebeneƤts. PerhapsthebestexampleofthisworkistheESRCǦfunded RELU study, led by Laurie Smith from SOAS at the University of London, which developed the concept of a ‘catchmentareapartnership’(CAP)and‘catchmentarea deliveryorganisations’(CADO)approachforthedelivery ofcatchmentmanagementinEnglandandWales. PilotedintheTamarandThurnecatchments,theproject drew on the scientiƤc and social accomplishments of several innovative catchment programmes in the USA and other European countries and examined how they couldbeadaptedforuseintheUK. The SOAS project established a clear catchment management ‘roadmap’ (above) on how to: create a catchment partnership, integrate scientiƤc investigation with policy, establish governance and legal provisions; foster decisionǦ makingandimplementationattheappropriategovernanceleveltoresolveconƪicts;andtosharebestpractice. SeveraloftheotherRELUresearchprojectstofocusoncatchmentmanagementcharacterisedapositivefeedbackloop in participatory catchment management planning whereby small initial changes initially yield a small beneƤt that, in turn, goes on to encourage far bigger changes later in the process. The common result of this feedback loop is the buildingoflocalcapacitythroughleveringintangiblenewresources,includingfreshcommitmentsoftimeandexternal fundingandthesupplyofexpertise.

Tȱɏ ‘CaWɭʕȷʑnɢ-Baȿeɍ ApʠUoaɭh’ (CɈƥA) In response to this increased understanding of the potential beneƤts of participatory catchment planning, undertaken with local stakeholders and knowledge providers, in 2011theEnvironmentMinisterRichardBenyonMPannouncedthattheUKGovernment wascommittedtoadoptingamore‘catchmentǦbasedapproach’tosharinginformation, workingtogetherandcoordinatingeơortstoprotectEngland’swaterenvironment. Followingtheirannouncement,DEFRAbeganworkingwiththeEnvironmentAgencyto explore improved ways of engaging with people and organisations that could make a realdiơerencetothehealthofourrivers,lakesandstreams. Inthesummerof2011,theylaunchedanewinitiativetotestthecatchmentpartnership approachinten'pilot'catchments.AlongsidethesetenEnvironmentAgencyǦledpilots they also established Ƥfteen further pilot catchments that would be hosted by other organisations. The outputs of the DEFRA Catchment Pilot Projects, which are now presented on the Catchment Change Management Hub website (ccmhub.net), reveal that the new partnerships created in many catchments were able to generate ambitious and comprehensiveplansfortheimprovementofriverecologicalhealthandwaterquality. InresponsetothesuccessofthePilotCatchments,inMay2013DEFRAannouncedtheir policyframeworkfortherollǦoutoftheCatchmentǦBasedApproach(CaBA)toallofthe ~80catchmentsinEnglandandcatchmenthostswillbeselectedinautumn2013. 67

TheDEFRACatchmentǦBasedApproach PolicyFramework,May2013.


CDŽSE SƼǟLjY CaWɭʕȷʑnɢ-Baȿeɍ ApʠUoaɭh (CɈƥA) PɵlԦɡ TodevelopanunderstandingofhowthecatchmentǦbasedapproachcouldworkinpractice,aseriesofcatchmentǦlevel partnershipsweredevelopedthroughapilotphase(May2011toDecember2012).Tenofthesepartnershipswerehosted bytheEnvironmentAgency(EA)and15wereledbyarangeofstakeholderssuchasRiversTrusts,Groundwork,water companiesandcommunitygroups.Agroupof41widercatchmentinitiativeswerealsoestablishedthatwerenotpartof theformalevaluation. Some examples of successful catchment partnerships established through the pilot phase of the catchmentǦbased approacharesummarisedbelow. TheTamarPlan TheTamarCatchmentPlanadoptedastakeholderǦled‘ecosystemservices’approach to catchment planning. This has involved the host organisation working with stakeholderstoidentifyareaswithinthecatchmentwhichplay,orhavethepotential to play, a particularly important role in the delivery of clean water and a range of otherbeneƤts(services)tosociety. Throughthisprocessthestakeholdershavedeveloped;(1)asharedunderstandingof the pressures aơecting ecosystem service provision in the catchment, (2) a shared vision for a catchment landscape with a blend of environmental infrastructure that maybeabletodeliverallofthesevitalservicesoptimallyinthefuture,and(3)aclear understanding of what is currently being done to realise this vision and what additionalactionsmayberequiredtobringittofullreality. SavingEden The Eden Pilot Project, hosted by Eden Rivers Trust within the Eden and Esk management catchment encouraged greater levels of participation including increased levels of engagement with ‘diƥcult to reach’ groups and facilitation of knowledgeexchangebetweenstakeholders.Thepilotprojectproducedaplancalled ‘Saving Eden’, which summarises the current health and the necessary actions requiredtodeliverGoodEcologicalStatusintheEdencatchment. Saving Eden says, ’we asked over 1,000 people, faceǦtoǦface or online, whether and whytheycareaboutriversandhowaplanmightwork...Peopletoldusthattheycare about things that aren’t really critical to WFD: beauty, wildlife, access and having water for them to use. Our catchment community wants a plan that is about these thingsaswell.Soourplanisgoingtobeaboutwhatpeoplecareabout,thenecessary WFD requirements, and achieving other parallel standards like those in the Habitats Directive.Wheretherearediơerentstandardswewillpursuethehighestonepossible.’ TheTyneCatchmentPlan TheTyneCatchmentPlanwascreatedbyTyneRiversTrustwhoaskedpeopleinthe catchment to tell them about the biggest issues for their rivers and to suggest projectstotacklethoseissues. The Tyne Catchment Plan, which is the result of that process, is a ‘wish list’ of proposedprojectsthatwill;(1)deliverbetterriversforpeopletoenjoyandvalue,(2) increase community involvement in local decisionǦmaking about river issues, (3) engage and educate those who don’t know the value and importance of rivers, (4) createrobustandresilientenvironmentswhichwillcopewithweatherextremesand climatechange,(5)makebestuseoftheavailableresources,researchandevidence insupportingworkacrossthecatchment,and(6)helpdeliverthetargetssetoutin EuropeanlegislationliketheWaterFrameworkDirectiveandtheHabitatsDirective. TheplanningprocessundertakenintheTyneCatchmentincludedasurveytowhich over 200 people responded and which raised 342 diơerent issues across the catchment.Theresultsofthissurveygavethemarealunderstandingofwhatpeople thinkisimportantforthefutureoftheTyneanditstributaries. The process also included a full assessment of all the projects already underway in thecatchmentanddevelopedaprioritisedlistof58newproposedprojectsthatthe catchmentpartnershipthoughtwouldbeimportantgoingforward.

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FɤԬȱʑɠ ʖnfʝʢPaʤiʝɚ & cʝnWacWɡ The Westcountry Rivers Trust is an environmental charity (Charity no. 1135007, Company no. 06545646) established in 1995 to secure the preservation, protection, development and improvement of the rivers, streams, watercourses and water impoundments in the Westcountry and to advance the education of the public in the managementofwater. Ourvisionis:Ǧ

 Ahealthierliving,workingnaturalenvironmentonalandscapescale.  Protectionofecosystemfunctionandnaturalresources,particularlywater.  Tofacilitatea movetowardsasocietythatvaluesthenaturalenvironmentandthe servicesitprovides–PaymentsforEcosystemServices.

 Educateandreconnectsocietywiththenaturalenvironment.  TobaseourworkongoodscientiƤcresearch. ToƤndoutmoreoutmoreabouttheWestcountryRiversTrustpleasevisitourwebsite atwww.wrt.org.ukorcontactoneofourteam; DrDylanBrightDirector Trained as alimnologist andfreshwaterecologist Dylan isDirector oftheRiversTrust and Managing Director of Tamar Consulting. He is an experienced farm and land managementadvisorandhasledDefrafundedprojectsinvestigatingWaterFramework DirectiveMetricsandimplementationofcatchmentmanagementplanstoinformgood status. Email:dylan@wrt.org.uk DrLaurenceCouldrickHeadofCatchmentManagement Dr Laurence Couldrick is the Head of Catchment Management at the Westcountry Rivers Trust and Project manager for the Interreg funded WATER Project on the PaymentsforEcosystemServicesapproachtoriverrestoration. Email:laurence@wrt.org.uk DrNickPalingGIS&CommunicationsManager Nickisanappliedecologistandconservationbiologistwith8yearsofexperienceusing spatial techniques to inform conservation strategy development and catchment management.Heprovidesdata,mapping&modellingsupportforallTrustprojectsand coordinates and manages a number of largeǦscale monitoring programmes currently beingundertakenbytheTrust. Email:nick@wrt.org.uk LucyMorrisDatatoInformationOƥcer Lucy is an ecologist and data analyst specialising in the communication of the Trust’s scientiƤc outputs to a wide variety of audiences. Lucy collates and assesses data and evidence before preparing press releases, articles and technical documents for publicationinavarietyofmediatypes,includingtraditionalprintmedia,Ƥlm/TV,online/ websitesandnewmediasuchassocialnetworkingsites. Email:lucy@wrt.org.uk HazelKendallUpstreamThinkingProjectOƥcer WorkingwithUpstreamThinkingpartnerstocollateinformationanddatacollectionfor reporting, Hazel will combine this role with bioǦmonitoring undertaken as part of the proofofconceptstudysupportingthephysicalworksoftheinitiative,usingarangeof samplingtechniquesandBioticIndices. Email:hazel@wrt.org.uk

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The Upstream Thinking Project is South West Water's ƪagship programme of environmental improvements aimed at improving water quality in river catchments in order to reduce water treatment costs. Run in collaboration with a group of regional conservationcharities,includingtheWestcountryRiversTrustandtheWildlifeTrustsof DevonandCornwall,itisoneoftheƤrstprogrammesintheUKtolookatalltheissues whichcaninƪuencewaterqualityandquantityacrossentirecatchments. The principal, overǦarching aim of any catchment management work is to improve the waterqualityinourfreshwaterecosystemsandtomakeasigniƤcantcontributiontotheir attainment of good ecological status in accordance with requirements of the EU Water FrameworkDirective.Itisthereforevitalthatsuƥcientevidenceiscollectedtoprovidean objectiveandrobustassessmentoftheimprovementsdelivered. In this review we explore the data and evidence available, which, taken together, demonstrate qualitatively and quantitatively that the delivery of integrated catchment management interventions can realise genuine improvements in water quality. To supporttheevidencecollected,wehavealsosummarisedanumberofcasestudieswhich demonstratecatchmentmanagementinaction.

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Upstream Thinking Catchment Management Evidence Review - Water Quality  

The principal, over‐arching aim of any catchment management work is to improve the water quality in our freshwater ecosystems and to make a...

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