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WATER QU LI Y Catchment Management Evidence Review

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Bringing people together to understand how to achieve a bettermore sustainable environment

COLLABOR8 is a transnational European project, funded by the Interreg IVB North WestEurope programme, which aims to contribute to the economic prosperity, sustainability andcultural identity of North West Europe in increasingly competitive global markets. This isbeing achieved by forming and supporting new clusters in the cultural, creative, countryside,recreation, local food and hospitality sectors using uniqueness of place as a binding force andovercoming barriers to regional and transnational collaboration.

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“Water is the driving force in nature.”Leonardo Da Vinci

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The Upstream Thinking Project is South West Water's agship programme ofenvironmental improvements aimed at improving water quality in rivercatchments in order to reduce water treatment costs. Run in collaboration with agroup of regional conservation charities, including the Westcountry Rivers Trustand the Wildlife Trusts of Devon and Cornwall, it is one of the rst programmesin the UK to look at all the issues which can in uence water quality and quantityacross entire catchments.

Published by:

Westcountry Rivers TrustRain Charm House, Kyl Cober ParcStoke ClimslandCallingtonCornwall PL17 8PH

Tel: 01579 372140Email: info@wrt.org.ukWeb: www.wrt.org.uk

© Westcountry Rivers Trust: 2013. All rights reserved. This document may be reproduced with priorpermission of theWestcountry Rivers Trust.

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CONT N S Introduction 6

Fresh water: a vital ecosystem service 6Pressures a ecting water quality 6Factors that determine pollution risk 7The catchment management ‘toolbox’ 10Assessing the e cacy of interventions 15

Pollutant Summaries 16Nutrients & algae 16Suspended solids & turbidity 28Pesticides 35Microbes & parasites 45Colour, taste & odour 52

Assessing improvements 57

Governance & planning 65

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INT OD C ON Fresh wat : vi l eco y t m vi Rain falling on the land brings life to the plants and animals living upon it, but it alsocollects and runs across the land forming rills, gullies, streams and ultimately rivers. Thetransfer of fresh water onto and then across the land is one of the fundamentalprocesses that sustain life on Earth. All of us depend on the fresh, clean water in ourrivers and streams every day – we drink it, we bathe in it and it sustains other life onwhich we depend for food and enjoyment.

Targets for the acceptable levels of pollutants in fresh water are set out in the EuropeanCommission’s Directive on the Quality Required of Surface Water Intended for theAbstraction of Drinking Water 1975 (75/440/EEC) and, more recently, in the EuropeanCommission’sWater Framework Directive 2000 (2000/60/EC).

While the former EC Directive refers to the quality of raw water intended for humanconsumption, the latter sets targets above which it is expected that the ecologicalcondition of a watercourse may be degraded.

In addition, Article 7 of the Water Framework Directive (2000) also stipulates that, for‘waters used for the abstraction of drinking water’, waterbodies should be protected toavoid any deterioration in water quality, such that the level of puri cation treatmentrequired in the production of drinking water is reduced.

While for most pollutants there is no inevitable link between the quality of raw andtreated drinking water, the level of contamination in raw water is directly linked to thediversity, intensity and cost of the treatments required.

Furthermore, there are certain pollutants or physical characteristics that, when theyoccur in the raw water, can severely a ect the e ciency of the drinking water treatmentprocess. When these pressures do occur, or when the water treatment process does nottake account of a speci c pollutant or group of pollutants, there can be an increased riskthat the treated drinking water may fail to reach the drinking water standards requiredat the point of consumption (the tap).

Pre ure ec ng wat q i Aquatic ecosystems can be damaged or degraded by a wide variety of pressures, whicharise either from human activities being undertaken in speci c locations (point sources)or from the cumulative e ects of many small, highly dispersed and often individuallyinsigni cant pollution incidents (di use sources).

Highly localised, point sources of pollution occur when human activities result inpollutants being discharged directly into the aquatic environment. Examples include therelease of industrial by products, e uent produced through the disposal of sewage, theover ows from drainage infrastructure or accidental spillage.

Superimposed on the pressures exerted by point sources of pollution are the morewidely dispersed and less easily characterised di use pollution sources.

When large amounts of manure, slurry, chemical phosphorus containing fertilisers oragrochemicals are applied to land, and this coincides with signi cant rainfall, it can leadto run o or leaching from the soil and the subsequent transfer of contaminants into awatercourse. In addition, cultivation of arable land in particular ways or the overdisturbance of soil by livestock (poaching) can make ne sediment available formobilisation and subsequent transfer to drains and watercourses by water running overthe surface.

Other di use sources include the run o of pollutants from farm infrastructure such asdung heaps, slurry pits, silage clamps, feed storage areas, uncovered yards and chemicalpreparation/storage areas.

Animal access to watercourses can also lead to the direct delivery of bacterial andorganic compounds to the water and to their re mobilisation following channelsubstrate disturbance. It should be noted that, while these agricultural sources ofpollution can often appear more like point sources, they are, however, considered asdi use sources as they relate to widespread, land based, rural practices that that canhave signi cant cumulative e ects.

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Pollutants that exert negative impacts on the quality of fresh water, degrade the healthof our aquatic ecosystems and contaminate raw drinking water are numerous andvaried. For this review, these pollutants are categorised under ve main headings:

Nutrients. Phosphorus & nitrogen containing compounds

Suspended solids. Including both sediment & organic material in suspension

Pesticides. Including other chemical pollutants from domestic sources

Microbiological contaminants. Including faecal coliforms & cryptosporidium

Colour, taste & odour compounds. Including metals & soluble organic compounds

Fac a det p i isk There are a number of factors in the landscape that determine the degree to which apollutant will become available in a particular location and the likelihood of it beingmobilised and carried along a pathway to a watercourse.

Soil character & conditionThe characteristics and condition of the soil in a particular area both play a key role inthe ability of the land to regulate the movement of water and the likelihood thatpollutants will become available for mobilisation into adjacent aquatic environments.

Some soils, such as heavy clay or peat based ‘stagnogleys’, are more susceptible todamage, such as compaction, caused by intensive cultivation or livestock farming. Thisincreases the risk of erosion or signi cant surface run o occurring from their surface.

Other soil types, such as lighter, free draining ‘brown earth’ soils, can have pollutantsleached away by water passing rapidly down through them. In addition, soils with veryhigh levels of organic matter, such as peat, can release large quantities of organiccompounds when they are drained or their structure has become degraded.

In light of this, it is clear that careful and appropriate management of soils can be apowerful method for minimising the risk of pollution occurring as a result of their innatestructural vulnerability.

Topography & hydrologyThe shape (morphology) of the land interacts with the underlying soil type and geologyto control the movement of water across the landscape. Some of the water falling onthe land as rain will be absorbed into the soil from where it can be taken up by plants orpass down into the groundwater held in the underlying geology.

When the soil is saturated or damaged or the underlying rock is impermeable, waterstops being absorbed and begins to move laterally across the land via surface or subsurface ow. Once moving through the landscape, water then collects in rills, gullies,drains and ditches, before entering our streams and rivers to make its way back the sea.

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INHERENT RISK

PRACT

ICE

The risk that an area of land poses tothe provision of an ecosystem service,such as the regulation of water quality,can be conceptualised as theinteraction between the inherentcharacteristics of the land and theactivities or practices being undertakenupon it. Therefore, it is possible toidentify areas where potentially riskypractices are being undertaken andwhere this coincides with a highunderlying risk that water quality couldbe degraded. These high scoring areascan be considered the priority for thetargeting of catchment managementinterventions and also where thegreatest enhancement of ecosystemservice provision may be achieved.

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In certain areas across the landscape, where there are steep converging slopes or wherethe land is at, water will naturally accumulate more than in other areas. In these‘hydrologically connected’ or ‘wet’ areas there is an increased likelihood, particularlyduring periods of heavy rainfall, that water will run rapidly across the surface andmobilise any pollutants that are available on the land surface.

Given the fact that certain areas, due to their morphology, have an elevated level ofhydrological connectivity and an increased probability that water will ow laterallyacross their surface, it is vital that we identify them and design tailored managementinterventions to mitigate any risk that they may generate pollution.

Land use & land coverThe use to which a parcel of land is put can have a signi cant e ect on its ability toregulate the movement of water across it and the likelihood that it will generatepollution in the aquatic environments nearby.

Natural habitats have rougher surfaces with more complex vegetation. They thereforehave a relatively low risk of becoming a pollution source as they are more likely to slowthe movement of water across the landscape, increase in ltration into the soil andincrease the uptake of water by plants.

In contrast to natural habitats, land in agricultural production experiences greaterlevels of disturbance, whether through cultivation or the actions of livestock, and thereis therefore greater risk that it will become damaged and become susceptible toerosion, pollutant wash o or pollutant leaching.

While it is certainly not always the case, the risk of pollution occurring is generally higherwhere land is in arable crop production or under temporary grassland. This is simplybecause the presence of bare earth for longer periods and the high intensity ofcultivation undertaken on this land increases the likelihood that the soil condition maybe degraded and pollutant mobilisation may occur.

Land under permanent grassland (pasture) inherently represents a lower pollution riskdue to its undisturbed soil and more mature vegetation. However, even this landuse cangenerate signi cant levels of pollution when its soil surface becomes damaged by highlivestock density or when large levels of nutrients or pesticides are applied to improve it.

When assessing the risk that di use pollution may occur, there are also areas of urbanand industrial landuse that should not be overlooked. Signi cant levels of pollutants(such as sediment, oil, metals, pesticides and a variety of other chemicals) can bemobilised from the often impermeable surfaces and drainage systems connected towatercourses in urban environments.

In light of these di erences in the ability of di erent land uses and land covers togenerate pollution, it is clear that either changing land use or ensuring that bestmanagement practices are undertaken on each particular land use represent the mostimportant methods for the mitigation of land use driven pollution risk.

Hydrological assessment of a river valley

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Practice & land managementWhile soil characteristics, morphology, hydrology and land cover all contribute theinnate potential for land to generate water pollution, it is ultimately the management ofland and the practices that are undertaken upon it that will determine the likelihood andscale of any pollution that occurs.

The intensity and timing of our activities can a ect the ability of land to retain pollutantsand so increase the likelihood of pollution arising from it. The risk of pollution occurringcan be increased when land is over stocked with livestock in vulnerable locations or attimes of elevated risk due to the increased chance of heavy rainfall. The risk can also beincreased when land is drained, compacted with machinery or when it becomesdamaged by repeated cycles of intensive cultivation and crop production.

Furthermore, the exogenous application of additional materials (manure and slurry) andchemicals (pesticides and fertiliser) to the land can increase the availability of pollutantsin certain areas at times when there is increased likelihood that they will be mobilisedand transported into aquatic ecosystems.

Finally, it is also important to consider the impacts that other human practices, such asrecreational and domestic activities, can have on the condition of land, the availability ofpollutants in certain areas at certain times and the risk they pose to the water quality.

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M p ng rea f vi i resh wat a eco y t m vi There are areas of land where, due to the physical characteristics of the location or a sudden change in the weather, anyland management practice, irrespective of whether it is inherently risky and despite best practice being observed, canstill result in the generation of pollution. On this high priority land, there is the greatest likelihood of water quality beingdegraded and for the ecosystem services dependent on it to be compromised. In addition, these are also the areas wherethe greatest environmental bene ts may be realised for the minimum investment.

Through combining data on soil characteristics, landuse, land topography and hydrological connectivity we can create amap of these innately risky and therefore the most important areas of land in a catchment (the example below showsand analysis of this type performed on the Tamar catchment).

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C SE S Y

Paul Anderson

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A Ca n M na n To b x If we can determine which pressures are exerting negative impacts on the water qualityin our aquatic ecosystems and identify their sources in a catchment, then we candevelop a programme of tailored and targeted interventions to remove these sourcesand disconnect their pollution pathways.

For many point sources of pollution, the scale of their contribution to the pollution loadin a watercourse can be characterised through monitoring and modelling approachesand then regulatory and technological measures can be implemented to mitigate theirimpacts.

In contrast to point sources of pollution, the various sources of di use pollution incatchments are far harder to identify and, individually, their impacts are often too slight,intermittent or transient to quantify with great accuracy and certainty. Despite thesechallenges, however, there is now a wealth of evidence and data which do allow thesedi use sources of pollution to be identi ed and for programmes of interventions andmeasures to be developed to mitigate their impacts.

Over the last 10 15 years a comprehensive suite of land management advice and onfarm measures has been developed to minimise loss of pollutants from farms whilemaximising e ciency to increase yields and save costs. Some of the most common ofthese so called Best Farming Practices (BFPs) that are now recommended to farmers,and which are now being delivered on farms across the UK, are illustrated on thefollowing page.

There are now many organisations that have skilled, knowledgeable and highly quali edfarm advisors who are able to give advice on farming practices, including; CatchmentSensitive Farming, Rivers Trusts,Wildlife Trusts, Soils for Pro t,Natural England, theEnvironment Agency and the Farming & Wildlife Advisory Group to name just a few. Inaddition, land managers also obtain a considerable amount of advice from their ownagronomists and farming advisors.

What is clear is that, irrespective of who is delivering an integrated farm advice andinvestment package, it should cover a broad spectrum of land management practicesand indicate where the adoption of good or best practice may minimise the risk that anactivity will have a negative impact on the environment and where it may enhance theprovision of an ecosystem service such as water quality provision.

During the development of the on farm intervention toolbox there were a number ofkey design considerations taken into account, which allow a farm advisor to correctlytailor and target their application:

Mechanism of action. It is important to understand the mechanism via which theintervention will reduce pollution. Often this will require the presentation of evidencethat it is the farming practice that is causing pollution before intervention isundertaken.

Applicability. Each measure must have the farming systems, regions, soils and cropsto which it can be applied clearly de ned. Farm advisors must recommendinterventions that are suitable for the situation found on a particular farm.

Feasibility. The ease with which the measure can be implemented and any potentialphysical or social barriers to its uptake or e ectiveness must be identi ed. Carefulconsideration must be given tomeasures that may impact other farming practices.

Costs & bene ts. The cost of implementing, operating and maintaining the measuremust be clearly understood. The potential practical and nancial bene ts to thefarmer of implementing the measure must also be estimated as it is vital forencouraging uptake of the measures. In some circumstances, where the cost is highor the measure will result in a loss of income, the farmer or farm advisor may need tond additional funding from incentive or capital grant schemes to enable delivery.

Strategically targeted. The measures need to be delivered into situations wherethey are most likely to have the desired water quality outcome. By ensuring that theright intervention is targeted onto the most suitable and appropriate parcel of land,the likelihood that the most cost e ective use of the investment has been madeincreases – i.e. the greatest possible ecosystem service improvement has beendelivered for the resources deployed.

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In this review, for each of the ve main pollutant categories, we give an overview of theinterventions that can been delivered to mitigate the impacts of pollution on; (1) theecological health of our river catchments, (2) the risks and costs incurred at drinkingwater treatment works through having to treat low quality raw water, and (3) on thegeneration of pollution derived problems in the estuaries and coastal regions in thelower reaches of river catchments.

Furthermore, we also describe the catchment management interventions considered tobe the most e ective in reducing di use pollution and mitigating the impacts described.We will also attempt to evaluate and summarise the numerous studies (completed orcurrently underway) which allow us to estimate the scale of bene t that thesecatchment management interventions can deliver at a variety of scales.

In assessing and collating this evidence, we hope that we will be able to demonstratewith some certainty that signi cant improvements in water quality can be achievedthrough the targeted and integrated implementation of catchment managementinterventions.

The catchment management intervention toolbox can be delivered through a variety ofapproaches, which are described in more detail in the sections below.

Farm visits and adviceAn integrated land management advice package will cover many aspects of a farmerspractice and will indicate where the adoption of good or best practice may minimise therisk that an activity will have a negative impact on the environment and where it mayenhance the provision of a particular ecosystem service.

In addition to broad advice on good or best practice, an integrated farm advice packageshould produce a targeted and tailored programme of measures that could beundertaken and should include speci c advice on pesticide, nutrient and soilmanagement on the farm to mitigate any potential environmental impacts.

Illustration showing some practices that can pose a threat to water quality (left side)and a wide array of Best Farming Practices (BFPs) (right side) which can minimize lossof pollutants to watercourses as a result of agricultural activity.

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Capital grants for on farm infrastructureWhere an advisor believes it to be appropriate, they will recommend in themanagement plan that improvements or additions be made to the infrastructure on afarm. Although some statutory designations, such as Nitrate Vulnerable Zones, dorequire certain standards in on farm infrastructure, under most schemes the uptake ofthese measures is entirely voluntary and the advisor will indicate funding mechanismsthrough which a grant may be obtained to contribute to the total cost of the work.

Incentivisation to change farming practiceAt present, farmers, who represent less than 1% of our society, currently manage nearly80% of our countryside and are largely responsible for the health of the ecosystems itsupports. However, despite their key role in managing our natural ecosystems, farmersare currently only paid for the provision of one ecosystem service; food production.

To redress this apparent imbalance, there are now a number of funding programmesthrough which land managers and farmers can receive payments for adopting moreenvironmentally bene cial and ecosystem services enhancing practices on all or part oftheir land. Schemes of this type, in which the bene ciaries of ecosystem servicesprovide payment to the stewards of those services, are often referred to as Paymentsfor Ecosystem Services (described in more detail in Assessing Improvements on p64).

The basic idea behind Payments for Ecosystem Services is that those who areresponsible for the provision of ecosystem services should be rewarded for doing so,representing amechanism to bring historically undervalued services into the economy.

Farming community engagement & educationEducational and training activities, such as farmer meetings and workshops, which raiseawareness of di erent initiatives and promote best practice among local farmingcommunities, are a key component of any catchment management programme. Theyalso serve to establish relationships and build trust between advisors and farmers on theground in a catchment.

AF ( ng E v n An F ng) LEAF is the leading organisation promoting sustainable food and farming. They help farmersproduce good food, with care and to high environmental standards, identi ed in store by theLEAF Marque logo. LEAF attempts to build public understanding of food and farming in anumber of ways, including; Open Farm Sunday, Let Nature Feed Your Senses and year roundfarm visits to our national network of Demonstration Farms.

LEAF is also an industry partner in the Campaign for the Farmed Environment (CFE), which is anopportunity for their members to demonstrate their commitment to protecting and enhancingthe farmed environment. As part of the Campaign, farmers are asked to ensure that a third oftheir ELS points come from a list of key target options. These include options which result incleaner water and healthier soil, protect farmland birds and encourage wildlife and biodiversity.

LEAF also provide a wide array of educational and best practice guidance resourceson their website, including their Water Management Tool, which o ers farmers acomplete health check for water use on their farms, and the Simply SustainableWater Guidance booklet and lm. The Simply Sustainable Water booklet has beenproduced to help farmers develop an e ective on farm management strategy fore cient water use and to improve their farm’s contribution to protecting water inthe environment. It allows farmers to get the best from this valuable resource, toimprove awareness of the importance of water and track changes in water use andquality over time.

Based on Six Simple Steps to help improve the performance, health and long termsustainability of their land, farmers are encouraged to set a baseline by assessingtheir water use and their water sources. The six key measures are: (1) water savingmeasures, (2) protecting water sources, (3) soil management, (4) managingdrainage, (5) tracking water use, and (6) water availability and sunshine hours.

C SE S Y

DevonWildlife Trust

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e o f ca n na n At present there are a number of di erent programmes and initiatives via whichcatchment management interventions are funded to deliver catchment scaleimprovements in water quality through the delivery of land management advice and onfarmmeasures.

Perhaps the most signi cant of these are; the Natural England coordinated CatchmentSensitive Farming initiative, some elements of the Natural England EnvironmentalStewardship Scheme and a number of newly established water company fundedschemes, such as the South West Water Upstream Thinking Initiative and the UnitedUtilities Sustainable Catchment Management Programme (SCaMP).

In addition to these programmes, the Environment Agency, Natural England, theForestry Commission and a number of non governmental organisations also makeconsiderable investment of their resources in the delivery of advice and practicalsupport for people managing natural resources in the catchment.

Each of these catchment management programmes have di erent funding mechanismsand use di erent methods to target and deliver funding. For example, CatchmentSensitive Farming o ers small medium grants (up to £10,000 per farm) for capitalinvestments in farm infrastructure in its priority catchments alongside a programme ofadvice and training. In contrast, Environmental Stewardship Schemes o er revenuepayments in return for the delivery of a suite of on farmmeasures in their target areas.

Ca n S n i F ng Funded by DEFRA and the Rural Development Programme forEngland, Catchment Sensitive Farming (CSF) is a joint initiativebetween the Environment Agency and Natural England that hasbeen established in a number of priority catchments across England.

C SE S Y

Overall, CSF has two principle aims: (1) to save farms money by introducing careful nutrient and pesticide planning,reduce soil loss and help farmers meet their statutory obligations such as Nitrate Vulnerable Zones, and (2) to deliverenvironmental bene ts such as reducing water pollution, cleaner drinking water, safer bathing water, healthier sheries,thriving wildlife and lower ood risk for the whole community.

To achieve these goals CSF delivers practical solutions and targeted support which should enable farmers and landmanagers to take voluntary action to reduce di use water pollution from agriculture to protect water bodies and theenvironment.

Catchment Sensitive Farming O cers work with independent specialists from the farming community to deliver freeadvice tailored to the area and farming sector. This advice includes workshops, farm events and individual farmappraisals. CSF also o er capital grants, at up to 60% of the total funding, to deliver improvements in farminfrastructure.

As part of the Catchment SensitiveFarming programme, Natural Englandhave also undertaken an evaluationstudy to demonstrate the bene tsthat the delivery of advice andmeasures have realised.

In addition to a summary report(http://tinyurl.com/mzyrpc7), NaturalEngland have also produced a numberof case studies and technical reportscovering speci c areas; such as,advice and education delivery, waterquality monitoring and environmentalmodelling. These can be accessed athttp://tinyurl.com/pk5rulg.

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Like Catchment Sensitive Farming, the South West Water Upstream Thinking initiativealso o ers capital grants for on farm infrastructure improvements, but it also placesconditions on the management of the new infrastructure and on other activitiesundertaken on the farm following the investment via a deed of covenant.

In addition, the Westcountry Rivers Trust, along with DEFRA and the University of EastAnglia, have recently investigated the potential of an innovative ‘reverse auction’approach to target the allocation of funding in a catchment (see below). This work,undertaken on the River Fowey as part of the Upstream Thinking Project and as part ofa DEFRA Payments for Ecosystem Services (PES) Pilot Project has demonstrated thecost e ectiveness of this method for the distribution of catchment managementfunding.

p re m T ng South West Water (SWW) in collaboration with a group of regionalconservation charities, including the Westcountry Rivers Trust, thecounty Wildlife Trusts for Devon and Cornwall and The Farmingand Wildlife Advisory Group, have established one of the largestand most innovative conservation projects in the UK: the ‘UpstreamThinking Initiative’.

This project will deliver over £9 million worth of strategic landrestoration in theWestcountry between 2010 and 2015.

C SE S Y

The ‘provider is paid’ funding mechanism used in the Upstream Thinking scheme is, perhaps, the most innovative aspectof the project. SWW have recognized that it is cheaper to help farmers deliver cleaner raw water (water in rivers andstreams) than it is to pay for the expensive ltration equipment required to treat polluted water after it is abstractedfrom the river for drinking. SWW believe that water consumers will be better served and in a more cost e ectivemanner if they spend money raised from water bills on catchment restoration in the short term rather than on waterltration in the long term. The entire 5 year initiative will cost each water consumer in the SouthWest around 65p.

Fowey River Improvement AuctionIn the rst scheme of this kind in the UK, an auction was successfullyused to distribute funds from a water company to farmers, investingin capital items to improve water quality. The work was supported bythe Natural Environment Research Council Business Internshipscheme, managed by the Environmental Sustainability KnowledgeTransfer Network.

The scheme o ered SWW the opportunity to work directly withresearchers from the University of East Anglia to devise aninnovative mechanism for paying for the delivery of ecosystemservices via their Upstream Thinking scheme.

Upstream Thinking uses an advisor led approach in other areas.Advisors from the Westcountry Rivers Trust visit farms to suggestwork and pay grants at a xed rate. The disadvantages of thisapproach are that it’s labour intensive, not practical to visit all farmsand the potential for all the funds to be used on a small number offarms. The main advantage is that advisors can suggest investmentsmost likely to improve water quality.

The University of East Anglia devised an auction approach, working with Westcountry Rivers Trust to: (1) increasecoverage by encouraging all eligible farmers to participate, and (2) achieve maximumwater quality bene ts at the sametime as achieving e ciency for SWW’s investment.

150 farmers in the Fowey catchment, were contacted in Summer 2012 with a list of capital investments eligible forfunding, plus additional farmmanagement practices which could be added to increase bid competitiveness.

Farmers were asked to enter sealed bids up to amaximum of £50,000 per farm.

42 bids were received, requesting a total of £776,000 and 18 bids met the value for money threshold, with grant ratespaid in the scheme from 38% to the full 100%.

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A e ng e ca nt n i n The principal, over arching aim of catchment management is to improve raw waterquality in lakes, rivers and coastal waters. If e ective, this approach could make asigni cant contribution to their attainment of good ecological status, in accordancewith the EUWater Framework Directive.

In addition, it could also reverse the escalating risks and costs associated with thetreatment of drinking water from our groundwater and surface water sources and itcould reduce the impacts of pollution on our most sensitive and highly productiveestuaries and coastal environments.

Given the potentially signi cant role of this approach in the improvement of waterquality, it is vital for that we collect su cient evidence to provide an objective andscienti cally robust assessment of the e ectiveness of the interventions used.

Ultimately, we must be able to justify that the money spent and the interventionsdelivered across the landscape have delivered both signi cant improvements in waterquality and a number of secondary nancial, ecological and social bene ts.

In this review we have attempted to collect a comprehensive and robust set of data andevidence, which, taken together, demonstrates qualitatively and quantitatively that thedelivery of integrated catchment management interventions can deliver genuineimprovements in water quality.

In sections 2 to 6 we have, for each of the main groups of pollutants, identi ed keysources of pollutant loads and examined the impacts these pollutants have on theaquatic environment, including how they translate into a cost or risk to society.

We have also identi ed key mitigation measures for reducing pollutant loads andevaluated the data and evidence for the e cacy of these measures. This process hasalso allowed us to identify the interventions for which the evidence of e cacy doesnot exist or where it does not exist at an appropriate scale.

Section 7 addresses issues of scale and reviews a selection of modelling tools thatcan be used to predict the impact of interventions and measures at a larger subcatchment or whole catchment scale. This section also explores the potential forsecondary environmental, economic and societal bene ts to result from the deliveryof catchment management interventions.

Section 8 reviews the governance structures currently being used to implement acatchment management based approach in the UK and explores some of theapproaches now being adopted to create catchment management plans.

Determine water quality impacts

Identify & qualify pressures

Locate sources & pathways

Develop programme of measures

Fund & deliver measures

Measure improvements

Record secondary bene ts

A summary of the cyclical and adaptivecatchment management process: fromthe characterisation of impacts to theidenti cation of pressures and on tothe delivery of measures and theevaluation of improvements achieved.

Assessing sh populations using electro shing

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T I N S & GAE

NUTRIEN

TS&ALG

AE

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Nitrogen and phosphorus containing compounds (often termed nutrients) are naturaland vital components of healthy aquatic ecosystems. They play a critical role insupporting the growth of aquatic plants, which, in turn, produce oxygen and providehabitats that support the growth and reproduction of other aquatic organisms.

Nitrogen and phosphorus containing nutrients also support the growth of algae,another natural component of many aquatic ecosystems. Algae occur in the benthic andplanktonic phases of freshwater habitats and form a key component of the food chainfor many species of sh, shell sh and invertebrate assemblages.

Unfortunately, when nutrients are released into the environment, deliberately oraccidentally, as a result of human activities, it can result in a perturbation of the nelybalanced equilibrium of nutrients cycling through the ecosystem.

When nutrients accumulate in aquatic ecosystems they drive the uncontrolled andunbalanced growth of aquatic plants and algae in a process called eutrophication andthese so called plant or algal ‘blooms’ can then cause severe problems for other aquaticorganisms, the ecological health of a waterbody and for the humans who also dependon the water for drinking water, recreational use or for the production of food such assh and shell sh.

S u e n There are three principal sources of nitrogen and phosphorus containing compounds ina river catchment: point anthropogenic sources, point agricultural sources and di useagricultural sources.

Point anthropogenic sources. A considerable fraction of the phosphorus in riverwater may be derived from inputs of sewage e uent (which may or may not havebeen treated), from drainage systems in urban areas, septic tanks and from roadsidedrains. The principal sources of phosphates and nitrates in sewage are human faeces,urine, food waste, detergents and industrial e uent that have been discharged tothe sewers. Typical sewage treatment processes generally remove 15 40% of thephosphorus compounds present in raw sewage and there are many small sewagetreatment facilities and septic tanks in rural areas which could also be makingsigni cant contributions to the phosphorus load in rivers and reservoirs.

Point agricultural sources. These include farm infrastructure designed to store andmanage animal waste and other materials such as animal food. Key infrastructureincludes dung heaps, slurry pits, silage clamps and uncovered yards. Animal accesspoints to watercourses can also lead to the direct delivery of phosphorus compoundsto the water and to their mobilisation following channel substrate disturbance.

Di use agricultural sources. When large amounts of manure, slurry or chemicalphosphorus containing fertiliser are applied to land, and this coincides withsigni cant rainfall, it can lead to run o and the transfer of phosphorus intowatercourses. This is a particular problem where heavy soils are farmed intensively,which can result in their compaction and an increased risk of surface run o .

There are a number of methods that can be used to estimate the level of nutrientenrichment in a watercourse and to determine where this contamination has beenderived from. For example, it is widely accepted that a detailed evaluation of thebenthic algae (diatom) communities in a river can provide a robust assessment of itsecological condition, because these diatom communities are particularly sensitive tochanges in the pH and nutrient levels in the water.

In addition to biological assessments, water quality monitoring can also be used tocharacterise the levels of nutrient enrichment in rivers and identify which sections of acatchment are contributing most to the nutrient load at any particular location.

However, water quality sampling can be costly and time consuming, when undertakenat ne temporal or spatial scales, and much of the work to identify sources of nutrientpollution in river catchments has therefore focused on the use of models such as theExtended Nutrient Export Coe cient Plus (University of East Anglia), the Phosphorusand Sediment Yield CHaracterisation In Catchments (PSYCHIC) model (ADAS WaterQuality) and the new Source Apportionment GIS (SAGIS) tool (Atkins UK).

N T I N S & A GAE

Robert Marshall

NUTR

IENTS

&ALG

AE

There are numerous potential sourcesof nutrients in river catchments;including sewage discharges (top),agricultural point sources such as slurrystores (middle) and di use sources suchas fertiliser applied to agricultural land(bottom).

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C SE S Y

S u A p i n -G S ( G S) od ng w k The Source Apportionment GIS (SAGIS) modelling framework was developed through UWKIR research projectWW02:Chemical Source Apportionment under the WFD (UKWIR, 2012) with support from the Environment Agency. Theprimary objective of this research was to develop a common modelling framework as the basis for deriving robustestimates of pollution source contributions that would be used to support both water company business plans and theEA River Basin Planning process.

The SAGIS tool quanti es the loads of pollutants to surface waters in the UK from 12 point and di use sources includingwastewater treatment works discharges, intermittent discharges from sewerage and runo , agriculture, soil erosion,mine water drainage, septic tanks and industrial inputs (UKWIR project WW02). Loads are converted to concentrationsusing the SIMulation of CATchments (SIMCAT) water quality model, which is incorporated within SAGIS, so that thecontribution to in stream concentrations from individual sources can be quanti ed.

Di use sources of nutrient pollution are incorporated into SAGIS from the Phosphorus and Sediment YieldCHaracterisation In Catchments (PSYCHIC) model (developed by a consortium of academic and governmentorganisations led by ADASWater Quality).

PSYCHIC is a process based model of phosphorus and suspended sediment mobilisation in land runo and subsequentdelivery to watercourses. Modelled transfer pathways include release of desorbable soil phosphorus, detachment ofsuspended solids and associated particulate phosphorus, incidental losses frommanure and fertiliser applications, lossesfrom hard standings, the transport of all the above to watercourses in under drainage (where present) and via surfacepathways, and losses of dissolved phosphorus from point sources.

The maps below show the baseline export of total phosphorus from manure based sources across the Tamar catchmentpredicted by the PYCHIC model (inset) and the modelled concentrations of Soluble Reactive Phosphate in subcatchments of the Tamar and their sources according to the SAGIS modelling tool (main).

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I pac n On the health of aquatic ecosystemsThe principal e ect of accelerated plant growth and algal blooms is the reduction(hypoxia) or elimination (anoxia) of oxygen in the water as oxygen consuming bacteriadecompose the plants and algae when they die back. This reduction in the oxygenationof a waterbody can have a severe e ect on the normal functioning of the ecosystem,causing a variety of problems such as a lack of oxygen needed for sh, shell sh andinvertebrates to survive.

Under the Water Framework Directive (WFD) classi cation scheme the ecologicalimpacts of nutrients on freshwater systems are recorded through the changes that theyexert on the plant and algal communities that are found in them. Changes in thecomposition of these communities are interpreted as an indication that nutrientenrichment is perturbing the ecological health of the ecosystem in that waterbody.

The impact of nutrients on the health of estuaries and coastal areas is still relativelypoorly understood but, as with freshwaters, excessive nutrient loads can cause theireutrophication. The susceptibility of estuaries to nutrient enrichment depends onfactors such as the physical characteristics, the hydro dynamic regime and the biologicalprocesses that are unique to each individual estuary. Generally speaking, estuaries andcoastal areas are thought to be less susceptible to eutrophication due to their tidalnature, which results in high turbidity (less light penetration) and frequent ushing.Estuaries with good light regimes are often more sensitive to nutrient enrichment.

Primary producers in estuaries may be opportunistic green algae, epiphytes orphytoplankton and excessive growth of any or all of these can impact on water turbidityand light availability, causing changes in the depth distributions of plant communities inthe water column. Such changes can have implications for the structure and functioningof estuarine and coastal food webs, with potential consequences for sh and shell shsheries and for bathing water quality on neighbouring beaches.

In addition to the assessment of these biological indicators, the levels of SolubleReactive Phosphorus (SRP) in waterbodies are also measured and, through comparisonwith established thresholds known to cause ecological impacts, the levels are used toidentify where degradation might be expected to occur. The WFD threshold abovewhich SRP is expected to have a signi cant impact on the ecological condition of anaquatic ecosystem varies between di erent waterbody types, but an average SRPconcentration above 50 ug/l would result in aWFD failure in any waterbody type.

Bob Blaylock

The Exe Estuary at Topsham

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Water starworts (Callitriche spp) (top)are just one group of macrophyteplants that can cause problems whenthey proliferate excessively. Phytobenthic algae (diatoms) are particularlysensitive to nutrient enrichment(bottom).

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On the provision of drinking waterIn addition to the ecological impacts of nutrient enrichment leading to hypoxia and/oranoxia in aquatic ecosystems, algal blooms can also result in other negative e ects thathave signi cant consequences for the treatment and supply of drinking water.

These include their potential to damage property or water supply infrastructure, toincrease algae derived toxins in the water and to cause taste and odour problems, all ofwhich can result in increased drinking water treatment costs.

These impacts are particularly felt as blooms of algae and explosions of macrophytegrowth begin to die back at the end of the summer growing season or following thedepletion of nutrients and oxygen in the water column, when a number of so calleddecomposition bi products can be released.

The three principal types of chemical pollutants produced as decomposition bi productsof this type are: (1) ammonia/ammonium (NH4), (2) soluble organic compounds (e.g.methyl isoborneol (MIB) and geosmin) and (3) dissolved metal ions (e.g. manganese).

Ammonia and its ionised cationic form ammonium (NH4+) are naturally occurringcomponents of the nitrogen cycle that are generated in aquatic ecosystems byheterotrophic bacteria as the primary nitrogenous end product of organic materialdecomposition. In healthy aquatic ecosystems ammoniacal nitrogen is readilyassimilated by plants or converted through nitri cation to nitrate, but in eutrophic lakes,where elevated levels of nutrients are driving algal blooms and the development ofstrati ed hypoxic conditions, this process can be inhibited and ammoniacal nitrogenthen accumulates rapidly.

The presence of ammoniacal nitrogen in water can begin to have a toxic e ect onaquatic organisms (especially sh) at concentrations above 0.2 mg/l. In addition, whenabstracted for drinking water treatment, ammoniacal nitrogen concentrations above0.2 mg/l can also cause taste and odour problems as well as decreased disinfectione ciency during chlorination.

The increased chlorination required to remove ammoniacal nitrogen during thetreatment process can also lead to the indirect generation of dangerous chemical biproducts such as trihalomethanes (THMs), which are thought to have toxic and/orcarcinogenic properties and are very di cult to remove from the nal treated drinkingwater. Furthermore, increases in the nitri cation of ammonia in the raw water, and theincreased consumption of oxygen that this entails, may also interfere with the removalof manganese by oxidation on the lters, which can result in the production of mouldy,earthy tasting water.

In 2002 the Environment Agency commissioned the University of Essex to undertake anassessment of the environmental costs resulting from the eutrophication of fresh waterecosystems in England and Wales. Their ndings, summarised in the table below,revealed that the total damage costs were in the range of £75 to £114 million.

Summary of the annual costs associatedwith freshwater eutrophication in theUK. Costs were calculated as ’damagecosts’ – i.e. the reduced value of cleanor non nutrient enriched water(adapted from Pretty et al., 2002).

Cost categoriesRange of annual costs(£ million)

Social damage costsReduced value of waterside dwellings £9.83Reduced value of waterbodies for commercial use (abstraction, navigation, livestock, irrigation and industry) £0.50 1.00Drinking water treatment costs (treatment and action to remove algal toxins and algal decomposition products) £19.00Drinking water treatment costs (to remove nitrogen) £20.10Clean up costs of waterways (dredging, weed cutting) £0.50 1.00Reduced value of non polluted atmosphere (via greenhouse and acidifying gas emissions) £5.12 7.99Reduced recreational and amenity value of water bodies for water sports, angling, and general amenity £9.65 33.54Revenue losses for formal tourist industry £2.94 11.66Revenue losses for commercial aquaculture, sheries, and shell sheries £0.029 0.118Health costs to humans, livestock and pets unknown

Ecological damage costs

Negative ecological e ects on biota (arising from changed nutrients, pH, oxygen), resulting in changed species composition(biodiversity) and loss of key or sensitive species

£7.34 10.12

TOTAL £75.0 114.3

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Mi i a i ea ure & e ca There are a wide range of mitigation measures available for reducing nutrient inputsinto the aquatic environment.

Soil, land and slurry managementLimiting fertiliser and manure inputs to suit crop requirements prevents over use andreduces the quantities of surplus nutrients entering the system. Mitigation measures tolimit nitrogen inputs to suit crop requirements have been shown to substantially reducenitrate losses from soil (Lord and Mitchell, 1998), but these methods are less e ective inreducing phosphorous concentrations in run o due to phosphorous build up in soil.

Mitigation measures to reduce nutrient loads through changes in agricultural land andsoil management practices include the use of fertiliser placement technologies andavoiding application of fertiliser to high risk areas. There are also a variety ofconservation tillage techniques that can be implemented, with the aim of reducingnutrient losses via surface run o .

Mitigation measures for improved soil, land and slurry management are listed belowand the evidence for their e cacy is summarised in the table below:

Implementation of conservation tillage techniquesFertiliser spreader calibrationUse of a fertiliser recommendation systemUse of fertiliser placement technologiesRe site gateways away from high risk areasDo not apply fertiliser to high risk areasAvoid spreading fertiliser to elds at high risk timesDo not apply P fertiliser to high P index soilsInstall covers on slurry storesIncrease the capacity of farmmanure storageMinimise volume of dirty water and slurry producedChange from slurry to solid manure handling system

Reference MitigationMeasure Findings

Benham et al. (2007) Implementation of conservation tillagetechniques

Mean losses in surface run o for

total nitrogen was reduced by 63%

ammonia was reduced by 46%

nitrate was reduced by 49%

total phosphorus was reduced by 73%

Daverede et al. (2004) Injection of slurry 93% reduction in dissolved reactive P in run o82% reduction in total P in run o94% reduction in algal available P in run o

Deasy et al. (2010) Tramline management Tramline management reduced nutrient and sedimentlosses by 72 99% on 4 out 5 sites and were a majorpathway for nutrient transfer from arable hill slopes

Goss et al. (1988) Direct drilling Winter losses of nitrogen was on average 24% less thanfor land that had been ploughed

Johnson and Smith (1996) Shallow cultivation (instead of ploughing) Decreased nitrogen leaching by 44 kg per hectare overa 5 year period

Pote et al. (2003) Incorporation of poultry litter in soil 80 90% reduction in nutrient losses from soil

Pote et al. (2006) Incorporation of inorganic fertilisers intosoil

Reduction of nutrient losses to the water environmentto background levels

Shephard et al. (1993, 1996 and1999), Goss et al. (1998), Lord etal. (1999)

Planting a green cover crop 50% reduction in nitrate losses compared to wintersown cereal. Uptake of nitrogen ranging between 10and 150 kg per hectare

Withers et al. (2006) Ensure tramlines follow contours of the landacross the slope

No signi cant di erences in run o quantity, sedimentand total phosphorous loads compared to areas with notramlines

Zeimen et al. (2006) Ensuring a rough soil surface by ploughingor discing

Transport of soluble phosphorus in surface run oreduced by a factor of 2 3 compared to untilled soils

The table below summarises keyndings of research into the e cacy of

mitigation measures aimed at limitingnutrient losses by changing agriculturalland and soil management practices.These ndings are a result of researchcarried out at either a plot or eldscale.

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TheWestcountry Rivers Trust haveproduced a series of farm measure factsheets, which can be found on theDEFRA website at—http://tinyurl.com/kqpyctv.

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R Ca n M na n P jec The River Otter rises in the Blackdown Hills in East Devon and runs for approximately 25 miles southwest to the sea.Below Honiton, the Otter enters its oodplain and runs south through several towns and villages before reaching the saltmarshes at Budleigh Salterton. In its lower reaches, the Otter becomes a gravel bed river that meanders through rollingtopography with mixed agricultural land use, including livestock, cereals, oil seeds, fruit and vegetables.

IssuesDue to the sandy nature of the soils in the Otter catchment, leaching of nitrate and pesticides is common. South WestWater (SWW) relies heavily on the lower Otter boreholes to meet local drinking water demands and many of theseboreholes have shown worrying trends in nitrate levels. Sediment and phosphate levels in surface waters are also highand in need of attention.

High nitrate levels increase the burden of supplying potable water and, although the SWW Dotton treatment plant iscapable of blending and stripping excess nitrate from the extracted water, its capacity is limited. Reducing the nitratecontent in raw water will reduced this burden and its associated economic and environmental costs.

Delivery of InterventionsFarm visits were made to engage with farmers and explain the bene ts of betternutrient management. Where appropriate, farmers were provided with farm reports tohighlight priority areas likely to in uence raw water quality and to provide advice onmanagement practices to reduce pollutant loads. From 2010 2012, thirty seven farmswere visited and eight received farm reports. Events were also held to engage with thefarming community whilst at the same time to bolster the understanding of the projectaims. Events have included fertiliser spreader workshops, crop trial workshops andvisits to the SWWwater treatment works.

Following the visit to the water treatment works one farmer commented that theproject was, “...very interesting. Our strategy has more in uence on water quality than Ithought...”.

Monitoring & OutcomesFocusing on the nitrate contribution from agriculture, a monitoring study was set up to assess the relative contributionsfrom di erent land use types within the catchment and to monitor changes in nitrate levels following farm visits.

Ten geographically diverse farmers kindly gave permission to use a single eld on each of their farms for testing, pre andpost winter. Each farmwas chosen carefully to ensure a representative selection of land use types were included.

The nitrate testing sites were selected in 2010 and sampling was undertaken in November 2010, March and November2011, March and November 2012 and March 2013. The di erence in nitrate levels recorded in the soil between NovemberandMarch gives a value for nitrogen lost over winter.

The chart (left) shows that overall levels of nitrogen lostfrom the soil has decreased signi cantly over themonitoring period, with levels in 2012/2013 approximatelya third of the level lost over the 2010/2011 winter.

The amount of nitrogen used by the current crop has beentaken into account, where appropriate, and the remainingfraction of nitrogen unaccounted for is considered to beassociated with the export of animal products, crops,leaching, de nitri cation and volatilisation. In most cases,the nitrogen loss will mainly be associated with leaching,volatilisation and de nitri cation, all of which areenvironmentally damaging.

While these results are encouraging, there are several other factors that could have contributed to this reduction, such asthe weather, and it is not possible to prove that these positive results are directly linked to interventions. However, theydo o er a snapshot of the problems faced in this area and certainly point towards a positive impact resulting from theprovision of nutrient advice on farm visits and in farm plans.

This monitoring work also provides invaluable data for the farmers participating in the project and helps to reinforce theproject aims, as demonstrated by positive farmer feedback.

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Management of livestockIn their Europe wide study into the sources of phosphorus inputs into rivers, Morse et al(1993) estimated that the most signi cant contributions were from livestock, humanwaste and fertiliser run o sources (see chart right).

Mitigation measures designed to reduce nutrients inputs from livestock are listed belowand the evidence for their e cacy is summarised in the table below:

Reduction in stocking density

Reduction in dietary N and P intakes

Exclusion of livestock fromwaterbodies and provision of alternative drinkingsources

Exclusion of livestock from poorly drained areas of land to prevent poaching andsubsequent mobilisation of soils and nutrients

Reference MitigationMeasure Findings

Heathwaite and Johnes(1996)

Reduced livestock grazing density Phosphorous exports in surface run o was recorded as:

2 mg total P per m2 for ungrazed land7.5 mg total P per m2 for lightly grazed land291 mg total P per m2 for heavily grazed land

Huging et al. (1995) Reduce livestock grazing density There is a signi cant relationship between grazing intensityand nitrogen losses to water

Nitrogen leaching losses were reduced by 69%

Kurz et al. (2006) Exclusion of livestock from poorly drainedareas of land to prevent poaching

Decreased concentrations of total nitrogen, organic phosphorous and potassium were measured in surface run ofrom un grazed areas when compared to grazed areas

Line (2003) Fencing the watercourse to exclude livestock combined with a 10 15m bu er strip

Total organic nitrogen load decreased by 33%

Total phosphorous load decreased by 76%

Parkyn et al.(2003) Fencing the watercourse to exclude livestock

Streams within fenced o areas showed rapid improvementin visual water clarity and channel stability

Soluble reactive phosphorous decreased by up to 33% insome streams, although in others it increased

Total nitrogen decreased by up to 40% in some streams butincreased in others

She eld et al. (1997) Provision of alternative drinking source forlivestock

Total phosphorus load decreased by 54%

Total nitrogen load decreased by 81%

E i e o k m po e rea n r n poa ng Poaching around feeding and drinking areas can lead to soil damage, as well as stock welfare and pollution problems,particularly during wet periods. Simple management changes can help farmers to bene t from:

improved stock health and lower vet bills

reduced soil damage, erosion, runo and watercourse pollution

improved grass production and nutritional value

reduced sward restoration costs.

reduced risk of damage to environmentally sensitive areas

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Careful management of out wintered stock and equipment in order to avoid seriousdamage to soils and sward was undertaken on 5 ha of grassland. Regular inspections,particularly in wet weather allowed movement to better drained areas before seriouspoaching occurred.

This resulted in 10% less grass to be restored, encouraged early recovery andprovided an early spring “bite”. Annual savings included 10% less grass to bereseeded @ £54/ha and 10% less loss of forage@ £24/ha. The total saving for 5hawas £390 with an immediate payback.

Sources of phosphorus in the EU

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B S p f n p i i i a i Creation of riparian bu er strips along watercourses is perhaps the most widely recommended mitigation method forcontrolling di use pollution losses from agriculture. Consequently, research into the e cacy of bu er strips in reducingpollutant load entering watercourses has been extensive.

E cacy (% reduction)

Reference Location Bu er Width (m) Soil Texture Slope (%) Phosphorous Nitrogen

Abu Zraig et al. (2003) Canada 2 Silt loam 2.3 57 64

5 47 60

10 5 65 72

15 2.3 55 93

Bar eld et al. (1998) USA 4.6 9 92

9.1 100

13.7 97

Barker et al. (1984) 79 99

Blanco Canqui et al. USA 0.7 Silt loam 4.9 44 63 62 77(2004) 54 72 35 36

22 53

4 77 82 82 83

81 91 54 70

71 84

8 87 91 88 90

96 99 83 84

87 95

Borin et al. (2004) Italy 6 Sandy loam 3 78 72

Cole et al. (1994) 2.4 4.9 Silt loam 6 93

Dillaha et al. (1988) UK 4.6 Silt loam 11 16 73 27

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9.1 93 57

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Doyle et al. (1977) UK 1.5 Silt loam 10 8 57

62 68

A riparian bu er strip can be de ned as a corridor of natural vegetationbetween agricultural land and a watercourse. They act as barriers to surfaceows and therefore impact on delivery of pollutants to watercourses. The

rate of surface run o is slowed as the water meets resistance fromvegetation and ows over rougher andmore porous surface material.

The substantial root systems beneath the surface also increase the likelihoodof in ltration. Slower owing water has a reduced capacity for the transportof particulate matter and, as a result, there is increased deposition ofsediment prior to surface ows reaching the watercourse.

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There are numerous factors that may in uence the performance of bu er strips in reducing pollutant load. These includethe characteristics of the incoming pollutants, the topography and soils of the land surrounding the watercourse and thecharacteristics of the bu er strip itself, for example vegetation type and width. In addition, seasonal variations inmeteorological conditions and farming practices can also in uence bu er strip performance.

The ndings of the many studies into the e cacy of bu er strip in mitigating nutrient losses from farmland are shown inthe table below. These results illustrate the variability inherent in quantifying the e cacy of bu er strips in reducingnutrient inputs to watercourses, with the range of e cacy for total phosphorus varying from 30 to 95% and for totalnitrogen, from 10 to 100%.

Continued over page...

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E cacy (% reduction)

Reference Location Bu er Width (m) Soil Texture Slope (%) Phosphorous Nitrogen

Duchemin &Madjoub 3 Sandy loam 2 85 96

(2004) 41

9 87 85

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Edwards et al. (1983) UK 30 2 47 49

Knauer &Mander (89) Germany 10 70 80 50

Kronvang et al. (2000) Denmark 0.5 Sandy loam 7 32

29 100

Kronvang et al. (2004) Norway 5 Silt loam 12 14 46 78

10 80 90

Lee et al. (2000) 7.1 Silty clay loam 5 28 72 41 64

Lim et al. (1998) USA 6.1 Silt loam 3 74.5 78

76.1

12.2 87.2 89.5

90.1

18.3 93.0 95.3

93.6

Magette et al. (1987) UK 9.2 Sandy loam 41 17

McKergow et al. (03) Australia Loamy land <2 6 23

Muenz et al. (2006) USA 25 Sandy clay loam 16.5 50 50

Patty et al. (1997) France 6 Silt loam 7 15 22 47

18 89 100

Parsons et al. (1991) USA 4.3 5.3 26 50

Schmitt et al. (1999) 7.5 Silty clay loam 6 48 35

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15 79 51

50

Schwer & Clausen 26 Sandy loam 2 89 92(1989) 92

Smith (1989) New Zealand 10 55 67

80

Syversen (1992) Norway 5 65 85 40 50

10 95 75

Thompson et al. UK 12 4 44

(1978) 36 70

Vought et al. (1995) Sweden 5 40 45 10 15

10 65 70 25 30

15 85 90 40 45

Young et al. (1980) UK 27 4 76 96 82 94

Zirschky et al. (1989) 91 Silt loam 38

Bu er Strips for nutrient pollution mitigation...continued….

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Delivery of interventionsAll thirteen farms in the Mill Creek catchment were paid to implement agricultural BMPs under a contract that calls for 10year maintenance of the practices in return for the technical and nancial assistance. Additionally two deed restrictionswere applied to two barns.

M l Cr k, P n i S at , A The Mill Creek catchment drains into the Stephen Foster Lake in the northern mountain region of Bradford County,Pennsylvania, USA. While greater than half of the surrounding 26 km2 catchment area is used for agricultural production,the remainder is predominantly forested.

Over time Mill Creek has deposited excess sediment and nutrient run o into the 28 Ha lake. As a result, Pennsylvaniaadded Stephen Foster Lake to the state’s list of impaired waters in 1996 for nutrient and sediment runo due toagricultural activities. Subsequently, a Total Maximum Daily Load (TMDL) for the lake that called for reductions of 49%for phosphorus was established.

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Catchment management planSeveral computer models were used to estimate the load reductions that might result from Best Management Practices(BMPs) being implemented. With the combination of these e orts, the nutrient runo was estimated to be reduced by52% and sediment runo reduced by 59%, exceeding the reduction recommended in the TMDL.

The suggested BMPs were primarily aimed at the control of nutrient inputs from animal wastes, which contribute anestimated 175 kg of phosphorus (10% of the total annual load). Erosion control, to further reduce nutrient and sedimentloadings to the lake, are estimated to reduce the total phosphorus load in it by an additional 10%.

Manure and runo from a previously severely degraded manure handling area is nowcontained and directed to the newmanure storage facility for eld application.

Farm feedlot before and after infrastructure improvements.

Upstream of the lake, farmers and the BradfordCounty Conservation District installed 9 miles ofstream fencing and alternative water supplysystems to help prevent cattle from wanderinginto waterways.

Agricultural crossings, to swiftly move cattleacross streams and prevent the animals fromgrazing near waterways and destroyingriverbanks were also constructed.

Project partners also built 11 systems to store andtreat animal waste, planted riparian bu ers, andrestored 2,500 feet of stream channel. TheBradford County Conservation District identi edover $518,000 worth of improvements to bedelivered over the 11 farms.

Growing Season Total Phosphate (TP) loads (kg) entering StephenFoster Lake before (1994 95) and after (2004, 2005, 2006 & 2008 09)delivery of Best Management Practices

Monitoring & OutcomesPennsylvania Department for Environmental Protection conductedbiological monitoring and analysis of Mill Creek. Across thecatchment there were four sample stations collecting monthlyreadings for pH, conductivity, a suite of Phosphate and Nitrogenmeasurements, alkalinity, total suspended solids and temperature.

Since 2004 the growing season Total Phosphate (TP) load enteringStephen Foster Lake declined by 50 to 90% relative to the originalPhase I study (1994 95) load. As a result of these reductions, thelake has been in compliance with its total phosphorus TMDLtargeted, growing season load since 2005.

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T e F m Int n i A e n The farm is located in the Tamar Lakes Catchment and has a rst order stream which runs next to the yard. The 98 Ha ofland is comprised of gently undulating pasture (60 Ha), arable (10 Ha in maize and 20 Ha in winter and spring barley) andwoodland. The main farm enterprise is a dairy with 130 milkers and 50 followers. There are around 60 bull calves and thefarmer has winter sheep kept over October to February. The dairy herd are housed over the winter months (Septemberto March) and the farm has approximately 4 months slurry storage capacity. Slurries are separated into a slurry lagoonand three dirty water pits. The slurry is spread over the land by the farmer using the farm’s ownmachinery.

InterventionAlthough the farmer demonstrated several good practices, there was a problem with his slurry store, which wasoutdated, could not cope with the demands of the modern dairy and did not a ord the environment with enoughprotection against leaks and over owing episodes. In this instance the ‘weeping wall’ slurry lagoon was placed too closeto watercourse and therefore ran the risk of polluting it.

In this situation the solution was to create a solid walled lagoon, which being slightly larger, allowed for slurry to beremoved and spread at appropriate times, as well as giving protection to the watercourse. The photographs below showthe formalisation of the slurry pit from an inadequate weeping wall system to a concrete, bunded system in early 2008.

MonitoringMonitoring of aquatic invertebrates was undertaken and taxa scored against the BMWP scoring system (BiologicalMonitoring Working Party National Water Council, 1981) to assess changes in agricultural pollution. Data was collectedover the term of the project from 2007 to 2009 and further monitoring was undertaken in 2012 to assess the long terme ects. Two sites one upstream and one downstream (separated by around 100m) allowed assessment of the impact ofthe intervention.

ResultsThe results of the BMWP scores show that there is asigni cant negative impact on water quality betweenthe upstream score (blue line) and the downstreamscore (red line) in the rst two samples before theintervention. After the intervention in Early 2008 (greenline) the di erence between the upstream anddownstream reduces suggesting that there is littlewater quality di erence between sites.

Although the 2012 upstream and downstream readingsare lower than the 2008 and 2009 readings there is stilllittle di erence between the two suggesting that therecontinues to be no impact from the site in terms ofwater quality.

MonitoringThe river is a small rst order stream, which goes part way to explaining the relatively low BMWP scores when comparedto second and third order streams in the area. It is highly likely that weeping wall slurry pit was having a signi cantnegative impact on downstream water quality and the intervention of formalising the pit reduced the di erence betweenthe two survey sites, both immediately after the intervention and four years later. The decrease in upstream anddownstream scores in 2012 is likely to be wider environmental factors such as an increase summer rainfall.

BMWP scores upstream (blue) and downstream (red) of a farmyard with aninadequate slurry pit with weeping wall. The slurry pit was updated in early2008 (shown as an green line) after which the di erence between the twoscores reduces. Whilst 2012 gures are reduced compared to 2008 & 2009 thedi erence between upstream and downstream is less than before intervention.

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Turbidity is a measure of how much suspended material there is in water. Turbidity isreported in nephelometric units (NTUs), which are measured by an instrument(turbidimeter or nephelometer) that estimates the scattering of light by the suspendedparticulate material.

There are many factors that can cause the turbidity of water to increase, but the mostcommon are the presence in the water column of algae, bacteria, organic wastematerials (including animal waste and decomposing vegetation) or silt (soil or mineralsediments). These materials are often released into the water following disturbance ofthe river or lake substrate, but they can also enter the water as a result of erosion andrun o from the land.

S u e nde i Numerous methods have been developed to identify the sources of suspended solidsand the dynamics of sediment transport in rivers. These methods, which vary greatly inthe spatial scales at which they can be applied, include:

Fine sediment risk modelling. Uses topographic, rainfall and land use data toidentify areas where a high propensity for the lateral ow of water over the land islikely to mobilise ne sediment and transport it to the river.

Sediment load sampling. Water sampling to determine suspended solid load and thecontribution being made by di erent sub catchments.

Sediment river walkover surveys. Rapid river surveys typically undertaken in wetweather to identify sources of sediment and organic material entering the river.

Source apportionment using uorescent, chemical and genetic signatures.Pioneered by research organisations, such as ADASWater Quality and the Universityof Plymouth, these approaches allow the areas of river bank or land that arecontributing to the in channel sediment load to be identi ed.

Overall these studies reveal that the sediment load in rivers is derived from point ordi use sources in three principal locations:

Material from the river channel and banks

Soil and other organic material washed o from the surface of surrounding land

Particulate material from anthropogenic sources; including point sources, roads,industry and urban areas.

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Examples of sediment being mobilisedfrom the land surface (in this case acountry road; top) and entering awatercourse (bottom).

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S P: A e n isk od ng w k A simple and robust ne sediment risk model can be extremely bene cial as it helps us to target and tailor both furthermonitoring work and catchment management interventions.

The SCIMAP ne sediment risk model was developed through a collaborative project between Durham and LancasterUniversities. The SCIMAP Project was supported by the UK Natural Environment Research Council, the Eden Rivers Trust,the Department of the Environment, Food and Rural A airs and the Environment Agency.

The SCIMAP model gives an indication of where the highest risk of sediment erosion risk occurs in the catchment by (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 andtransportation to receptor).

The combination of the sediment availability and hydrological connectivity maps results in a nal ne sediment erosionrisk model that is useful for targeting eld surveys and the mitigation of erosion risk at catchment, farm or eld scale.

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I pac nde i & u i i On the health of aquatic ecosystemsThe most obvious e ect of turbidity on the quality of water is aesthetic, as it gives theappearance that the water is dirty. However, suspended material in the water of riversand lakes can also cause signi cant damage to the ecology of the aquatic ecosystem byblocking the penetration of light to aquatic plants, clogging the gills of sh and otheraquatic organisms, and by smothering benthic habitats. This has the e ect ofsu ocating the organisms and eggs that reside in the interstitial spaces of the substrate.

Furthermore, where elevated turbidity is the result of algal or other microbial growththese organisms can also have direct toxic e ects on the ecology of the ecosystem (e.g.toxic blue green algae) or indirect e ects through the eutrophication of the watercolumn.

Suspended material in rivers and streams can also have a signi cant impact on theecological health, productivity and safety of estuarine and coastal environments in thedownstream sections of their catchments.

On the provision of drinking waterIn addition to their ecological impacts, turbidity and suspended solids also addsigni cantly to the intensity and cost of drinking water treatment as they canaccumulate in and damage water storage and treatment infrastructure.

Suspended sediment must also be eliminated from the water for e ective chlorinedisinfection of the water to be achieved.

Furthermore, particulates in suspension also carry other damaging and potentiallydangerous pollutants, including metals, pesticides and nutrients (such as phosphorus).Once removed from the water, the resulting sludge, which may be contaminated withthese other pollutants, must also be disposed of in a safe manner and this can beextremely costly when it is produced in large volumes.

In light of the impact that turbidity and suspended solids have on the e ciency and costof water treatment and on the aesthetic quality and safety of the nal drinking water, itis little surprise that the UK Water Supply (Water Quality) Regulations 2000 indicatethat treated drinking water should not have turbidity above 1 NTU.

In addition, the EC Directive on the Quality Required of Surface Water Intended for theAbstraction of Drinking Water 1975 (75/440/EEC) gives guidance that raw water shouldnot have Total Suspended Solids (TSS) above a concentration of 25 mg/l without higherlevels of treatment being undertaken before consumption.

In the water treatment processes undertaken at water treatment works, the suspendedmaterial in the raw water, and hence the turbidity, is removed by coagulation inducedby the addition of various coagulants (e.g. alum). The level of turbidity in the raw waterhas a signi cant e ect on the coagulation process. When turbidity is elevated, theamount of coagulant added must be increased and, at many treatment works, turbidity(along with colour) is one of the parameters that is constantly measured and used tocalibrate the dose of coagulant used in the treatment process.

Sediment pressure is felt at thesediment or sludge press of the watertreatment works (top). This generateslarge quantities of sediment or sludge‘cake’ which must then be safelydisposed of (bottom). Data indicatethat raw water polluted withsuspended sediment can double oreven triple the amount of sludgecreated at a works.

Sediment accumulation on a riverbed

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at q i & i o ic l i ng det e n pac In 2002, a sediment ‘ ngerprinting’ study undertaken on 18 rivers in England and Wales revealed that 69% of thesediment load in the River Tamar was derived from land surface sources and just 31% was from river channel/banksources (see below). The study found that this ratio was in stark contrast to the ndings in other Westcountry rivers. Forexample, in the other rivers of the wider Tamar catchment, the Tavy and Plym, just 10% and 8% of the sedimentrespectively were derived from surface sources (see below).

The authors believed that the predominance of land surface sources in the Tamar catchment was a direct result of thecatchments high stocking densities, which subject surface soils beneath pasture to severe poaching and subsequenterosion during rainstorms.

C SE S Y

Invertebrate community assessmentIt has long been recognised that benthic macro invertebrates are sensitive to the accumulation of ne sediment in rivers(Cordone & Kelly, 1961; Chutter, 1969; Richards et al., 1997) and in recent years the Proportion of Sediment sensitiveInvertebrates (PSI) index has been developed as a biological indicator for the assessment of ne sediment accumulationin rivers. The PSI index assigns families and species of benthic macro invertebrates a sensitivity rating from 0 100 forsediment according to their anatomical, physiological and behavioural adaptations. The scores for the taxa found in asample are summed to give the sample an overall PSI score.

The development of the PSI index and its incorporation intothe RIVPACS database in 2011 has allowed invertebratesampling to be used as a biological method for the assessmentof ne sediment load across the Crownhill WTWs catchment.Duplicate (two season) invertebrate samples were taken at 30locations across the catchment. Each sample was identi ed tospecies level and the PSI index calculated.

At each sampling location environmental measurements werealso taken and entered into the River Invertebrates AnalysisTool (RICT), which uses the RIVPACS database to predict whatthe PSI index score should have been for that site.

The Ecological Quality Ratio (EQR) for the sample is thencalculated as the ratio between the observed and the expected(O/E) score.

The ndings of this invertebrate study (above right) show that several waterbodies in the Tamar catchment appear tohave invertebrate assemblages that are impacted by ne sediment. The observation that the most impacted areas are inthe Upper Tamar, Ottery and Lower Tamar sub catchments is entirely in accordance with our previous ndings and withthe Environment AgencyWFD Reasons for Failure database.

Water chemistry samplingTo further investigate the sources ofsuspended solids in the Tamar catchment, atelemetrically linked multi parameter probe(sonde) was installed to identify occasionswhen heavy rainfall had triggered high owevents in the river and a corresponding spikein the turbidity of the river had occurred.

Water quality samples were then taken andanalysed to identify the relative suspendedsolids contribution being made by each subcatchment at those times (right).

The provenance of interstitial sediment samplescollected from study catchments in south westEngland. Source apportionment was performedusing the sediment ngerprinting technique(adapted fromWalling et al, 2002).

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Se n i i a i ea ure & e ca There are a wide range of mitigation measures available for reducing sediment loadsand turbidity in the aquatic environment. These measures are primarily aimed atreducing the availability of sediment sources, at reducing the likelihood of materialbeing mobilised and at disconnecting the pathways via which particulate matter (mainlysoil) is carried into watercourses. Measures include:

Early harvesting and establishment of crops in Autumn

Cultivation of land for crops in Spring rather than Autumn

Adopt a reduced cultivation system

Cultivate compacted tillage soils

Cultivate and drill across the slope

Leave autumn seedbed rough

Manage over winter tramlines

Loosen compacted soil layers in grassland elds

Reduce eld stocking rates when soils are wet

Construct troughs with a rm but permeable base

Move feeders at regular intervals

A wide and varied body of research has been conducted over the past 40 or so years inthe attempt to quantify and understand the processes of soil erosion on agricultural landin the UK and how it can be reduced.

There are numerous conservation tillage techniques that have been shown to reducesoil erosion and it is well documented that rough soil surfaces on arable land reduce runo and increase the water holding capacity of the soil, thereby preventing mobilisationand transportation of particulate matter to watercourses.

The table below summarises the key ndings from the Mitigation Options forPhosphorus and Sediment (MOPS) project— a collaborative research project, funded bythe UK Department for Environment, Food and Rural A airs (DEFRA), and involvingfour project partners, Lancaster University, ADAS, the University of Reading and TheGame & Wildlife Conservation Trust Allerton Project. The project was designed to testthe e ciency of a range of mitigation measures aimed at reducing sediment throughconservation tillage techniques.

Mitigation measure Reduction in suspended sediment

Contour cultivation 64 76%

Minimum tillage 37 98%

Tramline modi cation 75 99%

Beetle bank construction 16 94%

Summary of key ndings from theMitigation Options for Phosphorus andSediment (MOPS) project that aimed totest the e ciency of a range ofmitigation measures aimed at reducingsediment through conservation tillagetechniques. (From Stevens and Quinton,2008.)

rec ng: um a te iq Direct drilling is a system of seed placement where soil is left undisturbed with crop residues on the surface from harvestuntil sowing. Seeds are delivered in a narrow slot created by discs, coulters or chisels.

Direct drilling o ers the potential for savings over traditional plough based crop establishment systems due to lowercosts associated with machinery, energy, soil damage, soil erosion, nitrogen leaching and agrochemical losses. It alsoo ers substantial environmental bene ts, such as increased soil fauna and habitats for birds, as well as a reduced risk ofwatercourse pollution.

C SE S Y

System Depth(cm)

Cost (£/ha)

Time(mins/ha)

Cereal yield(%)

Plough 15 35 100 135 150 220 100 Direct drilling 0 30 45 25 40 99.2

The Soil Management Initiative (SMI) Guide toManaging Crop Establishment says the method gives‘a dramatic reduction in establishment costs and anincrease in work rate, improved control of black grassand reduced slug activity’ Source Cran eld University

A sub soiler (top) and a roughcultivation (bottom) both goodmethods for maintaining good soilstructure throughout the year

Blonder1984

Amanda Slater

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B S p f e n p i i i a i As we have described for nutrient pollution, the e cacy of bu er strips in reducing suspended sediment loads inwatercourses has also been the subject of a signi cant body of research. The ndings of this research, summarised in thetable below, indicate that bu er strips can reduce sediment losses from between 33 and 100% in plot and eldexperiments and that percentage reduction is primarily in uenced by bu er strip width.

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Reference Location Bu er Width (m) Soil Texture Slope (%)E cacy

(% Sediment reduction)

Arora et al. (1996) USA 1.52 Silty clay loam 3 40 100

Blanco Canqui et al. USA 0.7 Silt loam 4.9 81 92

(2004) 4 94

8 98 99

Borin et al. (2004) Italy 6 Sandy loam 3 93

Dillaha et al. (1988) UK 4.6 Silt loam 11 16 63

9.1 78

Duchemin &Madjoub 3 Sandy loam 2 87

(2004) 9 90

Gha arzadeh et al. (92) 9.1 7 12 85

Homer &Mar (1982) USA 61 80

Kronvang et al. (2000) Denmark 0.5 Sandy loam 7 62

29 100

Kronvang et al. (2005) Norway 5 Silt loam 12 14 60 87

10 90

Lee et al. (2000) 7.1 Silty clay loam 5 70

Lim et al. (1998) USA 6.1 Silt loam 3 70

12.2 89.5

18.3 97.6

Lynch et al. (1985) 30 75 80

Jin et al. (2002) USA 19 4 62

17 6 38

4 4 64

Magette et al. (1987) UK 9.2 Sandy loam 72

McKergow et al. (2003) Australia Loamy land <2 93

Muenz et al. (2006) USA 25 Sandy clay loam 16.5 81

Patty et al. (1997) France 6 Silt loam 7 15 87

18 100

Schellinger & Clausen(1992)

22.9 33

Schmitt et al. (1999) 7.5 Silty clay loam 6 63

15 93

Schwer & Clausen (1989) 26 Sandy loam 2 95

Smith (1989) New Zealand 10 87

Verstraeten et al. (2002) Belgium 20 Silty clay loam <2 41

Wong &McCuen (1982) 30.5 2 90

61 95

Young et al. (1980) UK 27 4 67 79

Ziegler et al. (2006) Thailand 30 Sandy loam 34 87

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P S I S PE

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P S I S Chemicals that are used to kill or control ‘pest’ organisms are referred to generically as‘pesticides’. In agricultural and horticultural uses these chemicals are grouped accordingto their target organisms and include herbicides (weeds), insecticides (insects),fungicides (fungi), nematocides (nematodes) and rodenticides (vertebrate poisons).

In agricultural applications, pesticides are widely used to protect crops and livestockfrom pests and diseases and, when used with care, they can deliver substantial bene tsfor society: increasing the availability of good quality, reasonably priced food and wellmanaged urban environments.

Despite the potential bene ts of pesticide use, however, it is important to note that,following their application, large amounts of pesticide often miss their intended targetand are lost into the environment where they can contaminate non target species, air,water and sediments. Pesticides are, by design, harmful to living organisms and so,when they do accumulate in these non target locations, they can pose a signi cantthreat to ecosystem health, biodiversity and human health if the risks are not accuratelyassessed and appropriate measures taken to minimise them.

S u e e i ide Pesticide pollution occurs primarily through two routes:

Point agricultural sources. Such as leakage, spillage or accidental direct applicationto a watercourse (for example as the result of spray drift)

Di use agricultural sources. Where active ingredients are washed o or leachedfrom the soil following their application.

The threat posed by an individual pesticide is also dependent on the unique intrinsicproperties of the active ingredients, which determine the speci c risk they pose in termsof water pollution and the ease of their subsequent removal from drinking water. Theseintrinsic properties include:

Pesticide half life. The more stable the pesticide, the longer it takes to break downand the higher its persistence in the environment.

Mobility & solubility. All pesticides have unique mobility properties, both verticallyand horizontally through the soil structure. Many pesticides are designed to besoluble in water so that they can be applied with water and easily absorbed by thetarget. A pesticide with high solubility also has a far higher risk of being leached outof the soil and into a watercourse. In contrast, residual herbicides have lowersolubility to facilitate their binding to the soil, but their persistency in the soil can alsocause problems.

Mecoprop (herbicide)

MCPA (herbicide)

Glyphosate (herbicide)

Cyromazine (insecticide)

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In addition to the intrinsic characteristics of each pesticide, there are also severalextrinsic factors that can determine whether a pesticide poses a risk in a particularsituation:

Rainfall. High levels of rainfall increases the risk of pesticides contaminating water.Water moving across or through the soil can wash pesticides into watercourses orthey can be transported into the water bound to treated soil via soil erosion.

Microbial activity. Pesticides in the soil are broken down by microbial activity andthis degradation is expedited where the levels of microbial activity are high due tothe presence of high numbers of microbes or elevated soil temperature. Pesticideresidues can also be degraded through evaporation and photo decomposition.

Application rate. The more pesticide that is applied, the longer signi cantconcentrations remain available to be transported into the water.

Treatment surface. Pesticides are generally designed to be applied to soil basedsystems where they are held before being taken up by the target organism. Whenpesticides are applied to non porous surfaces (such as concrete or tarmac) or to soilthat is degraded, they are not absorbed by the soil and are therefore particularlyvulnerable to mobilisation into watercourses following rainfall.

A e ng e i id p i isk ng pa i l od l The principal aim of this approach is to identify areas where the use of pesticides applied to the land represents apollution risk due to an elevated likelihood that they will be mobilised and transported through or over the soil and into awatercourse.

A number of proprietary tools and modelling approaches have been developed to assess the spatial risk of pesticidepollution. These include the Cran eld University CatchIS tool, the ADAS Pesticide Risk Assessment Model and the GfKKynetec i MAPWater system, but all are essentially based on similar conceptual models.

C SE S Y

We used the i MAP Water system to model pesticide applicationrates across the sub catchments of the Tamar catchment. It isgenerally accepted that, while the i MAP dataset is robust atcatchment or sub catchment scale, its aggregation to a nerscale than the sub catchment level would result in signi cantinaccuracy in the nal model.

To achieve our modelling aim we developed a spatial mappingprotocol (summarised right), which is essentially based on theapplication rate of the pesticide (derived from the i MAP system),the landuse for which it is used, the propensity of the soil torelease pesticides by leaching or run o , and the hydrologicalconnectivity of the land.

Using this method we have developed risk models for all of the active ingredients detected in the Crownhill watertreatment works catchment. Risk maps derived for two acid herbicides; Mecoprop and MCPA, and one neutral herbicide;Chlorotoluron are shown below.

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A e ng e i id p i oa ng pa ng Taking samples of river water using the conventional method of lling bottles byhand can be costly and time consuming. The results obtained from these ‘spot’samples can, at best, only provide a snapshot of the concentration target compoundswhich may be present at the time of sampling.

Subsequent interpretation of the analytical results obtained is also di cult (was it theleading edge of a pollutant plume, the peak, or the trailing edge?) and the time lagbetween these results and repeat samples or remedial action inevitably means theenvironmental investigation is reactive in nature.

Recently, a number of alternative and innovative monitoring strategies have beenproposed to overcome these challenges. In particular, research is focusing on the useof passive samplers which can be deployed alone or, more often, in conjunction withspot sampling to provide addition data on water quality and pollutant loads in rivers.

C SE S Y

Recently, a research collaboration between South West Water, the University ofPortsmouth, Natural Resources Wales and the Westcountry Rivers Trust has beenestablished to use the ChemcatcherTMpassive sampler (developed at the University)to investigate water quality in this area.

Chemcatcher™ is a small plastic device tted with a speci cally tailored receivingphase disk that has a high a nity for the target compounds of interest. Di erentphases are available to sequester non polar (e.g. poly aromatic hydrocarbons andsome pesticides) and polar pollutants (e.g. pharmaceuticals and personal careproducts), heavy metals (e.g. cadmium, copper, lead and zinc) and some radionuclides (e.g. caesium).

In practice, the receiving phase disk is overlaid with a thin di usion limitingmembrane. These devices can be used to obtain the equilibrium concentration of thepollutants or more typically the time weighted average (TWA) concentration overthe sampling period.

The rst riverine trials using the ChemcatcherTM involved investigatingpesticides along the River Exe; a river designated as a WFD Article 7Drinking Water Protected Area (DrWPA) with additional SafeguardZone (SGZ) status that requires a formal ‘action plan’ to be drawn upby the Environment Agency. Here the aim was to ‘ eld test’ thetechnique and hopefully provide an understanding of where the worstproblem pesticide loadings and locations were.

Over a two week period in early May 2013, timed to coincide withknown agricultural applications and forecasted rainfall, a number ofdevices were deployed along much of the length of the river.

ChemcatcherTM samplers were housed in a number of speciallyfabricated metal cages supplied by Anthony Gravell, TechnicalSpecialist at Natural Resources Wales Llanelli Laboratory, whospecialises in passive sampling in conjunction with HPLC MStechniques for the analysis of pesticides, pharmaceuticals andendocrine disruptors in various environmental compartments. Eachcage held three replicate sampling devices and was weighted to ensurestability (see images right).

Prior to the trials, researchers at the University and South West Water’sOrganics Laboratory worked together to identify a receiving phase diskcapable of sequestering a group of nine speci c pesticides that arecommonly detected in raw waters in the SouthWest.

Prior to the eld deployment, laboratory tests were undertaken using a large tank lled with River Exe water and spikedwith known concentrations of the pesticides under investigation. Here the aim was to measure the uptake kinetics (andhence the sampler uptake rates) of these chemicals over a two week period. Once these data were available, they werethen used to estimate the TWA concentrations of these pollutants in the river over the eld trial period.

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A e ng e i id p i re ur ng at nd x: P AR Another approach we have adopted is the assessment of invertebrate assemblages using the newly developed SPEciesAt Risk Pesticides (SPEARPESTICIDES) index (Liess and von der Ohe, 2005). This index assesses the degree to which theinvertebrate assemblages in the river are being a ected by the presence of pesticides (and insecticides in particular) usingthe life history and physiological traits to develop sensitivity scores for each species.

The continuous exposure of the invertebrate fauna in a stream to the pesticide load in the water makes them an excellentindicator of pesticide pressure across a catchment in a way that water quality sampling cannot achieve unless undertakenwith very high frequency.

C SE S Y

In 2011, the SPEARPESTICIDES index was also added to the RiverInVertbrate Prediction and Classi cation System (RIVPACS)database and this facilitated its use in the same year as abiological method for the assessment of pesticide pressure acrossthe Crownhill water treatment works catchment.

Invertebrate samples taken across the catchment were identi edto species level and the SPEARPESTICIDES index calculated. TheRiver Invertebrates Analysis Tool (RICT) was then used to predictwhat the SPEARPESTICIDES index score should have been for thatsite and the Ecological Quality Ratio (EQR) for the samplecalculated as the ratio between the observed and the expected(O/E) score.

The ndings of the Crownhill WTWs catchment SPEARPESTICIDES

invertebrate study are summarised in the map (right).

I pac e i ide On the health of aquatic ecosystemsPesticides contain active ingredients designed to kill certain groups of organisms and,as such, there is signi cant potential for them to pose a threat to the health of othernon target species (including humans), habitats and ecosystems when they accumulatein the environment.

Direct e ects of pesticides on vertebrates have been greatly reduced since the phasingout of organochlorines, but there are a number of active ingredients, such as themolluscicide methiocarb, which have been shown to exert toxic e ects on vertebratenon target species (Johnson et al., 1991).

Many herbicides are also known to have negative impacts on invertebrate abundanceand species diversity (Chiverton and Sotherton, 1991; Moreby, 1997), while insecticideshave been shown to have signi cant impacts on both terrestrial and aquaticinvertebrate communities (e.g. Moreby et al., 1994). Some fungicides have also beenimplicated in reducing invertebrate abundance (e.g. Reddersen et al., 1998).

Other studies (Williams et al., 1995) have shown that pesticide ushes can occur at theheadwaters of streams, where stream fauna could be a ected. This is of particularconcern because such waters are otherwise of high quality and may be sh nurserygrounds.

Most recently, in 2013, an extensive analysis of the e ects of pesticides on communitiesof stream invertebrates in Europe and Australia found that they caused signi cante ects on both the species and family richness, with losses in species richness of up to42% recorded (Beketov et al., 2013).

As a result of these ndings, the Water Framework Directive sets thresholds for manykey pesticides, such as Diazinon, Linuron and Cypermethrin, above which they may beexpected to be damaging the aquatic environment and/or pose a threat to humanhealth (so called ‘speci c pollutants’). The WFD also sets targets for several hightoxicity (and largely banned) pesticides, such as Atrazine and DDT, which are classi edas ‘priority’ or dangerous substances under the EU Dangerous Substances Directive.

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On the provision of drinking waterWater companies are required by law to assess the risk that pesticides pose to each oftheir raw water sources and also to monitor these sources for the presence of any ofthese compounds.

The European Drinking Water Directive stipulates that there must be no individualpesticide detected in drinking water at concentration over 0.1 g per litre. However,over recent decades, as a result of this stringent standard, the continued contaminationof river and ground water sources with pesticides has driven water companies to investin ever more advanced water treatment processes to remove them from drinking water.

There are several methods available for the removal or reduction of pesticideconcentrations in treatment of drinking water. Blending with water from an uncontaminated source can be e ective as can blending treated water, but these methodsoften require lengthy and costly transfers of water or are simply not feasible.

At the water treatment works, the methods available for the reduction of pesticideconcentrations can be divided into adsorption processes, biological processes,destruction processes and physical removal processes. These include:

Granular activated carbon (GAC) adsorption

Powdered activated carbon (PAC) adsorption

Ozone GAC – destruction/adsorption/biological

Ultraviolet irradiation destruction

Advanced oxidation destruction

Nano ltration reverse osmosis – physical removal (size exclusion)

All of these processes are expensive to undertake, in terms of both the infrastructureinvestment required and their running costs, and all are highly energy and resourceintensive.

Furthermore, there are a number of pesticides for which these high intensity processescan remain ine ective (such as metaldehyde; see below) and there remains aconsiderable risk that these contaminants could still be passed on into the nal treatedwater supplied to customers if further precautions are not taken.

Metaldehyde is a selective pesticideused by farmers and gardeners tocontrol slugs and snails in a wide varietyof crops. Technically it is known as a‘molluscicide’ and its action is veryspeci c to slugs and snails)Metaldehyde is sold under a variety ofbrand names in pellet form.Metaldehyde is an issue for watercompanies, because pellets applied tocrops on land can nd their way intodrains and water courses either directlyduring application or as a result of runo during high rainfall events. Levels ofmetaldehyde have been detected intrace concentrations in the rivers orreservoirs at levels above the Europeanand UK standards set for drinkingwater. Current drinking watertreatment methods are not e ective atreducing the levels of metaldehyde inwater. There have been occasions whenvery low levels of metaldehyde havebeen detected in treated drinkingwater. These levels are extremely low –the highest being around 1ug/l andmostly much lower. However the levelsare above the European and UKstandards for pesticides in drinkingwater that is set at 0.1ug/l.

Advanced water treatment solutionsrequired to remove pesticides fromdrinking water include powderedactivated carbon (top), granularactivated carbon (GAC) lters (middle)and ultra ltration (bottom).

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Pe i id i i a i ea ure & e ca High pesticide inputs to watercourses are most likely to occur due to direct applicationor when rainfall causes surface run o or leaching shortly after application. Mitigationmeasures to reduce pesticide inputs therefore fall into three main categories:

Best practice advice and education. Encouraging measures to prevent directapplication or point source loss of pesticides to a watercourse or drainage system.

Land management and soil management advice. Soil management measures toprevent rapid run o or leaching which ensure that pesticides are taken up by targetspecies or broken down in the soil rather than being available to cause pollution.

Landuse change and the improvement of farm infrastructure. Mitigation measures(e.g. bu er strip and riparian wetlands) designed to intercept surface run o andensure pesticides are broken down before reaching the watercourse.

Pesticide best practice advice & educationMany pesticide contaminations occur as the result of poor practices undertaken duringtheir transportation, storage, preparation or application. These so called point sourceinputs of agricultural pesticides mainly occur from hard impermeable surfaces (such asfarmyards, storage facilities or roads), which become contaminated during the llingand cleaning of sprayers, improper disposal of un used mix, leaks from faultyequipment, incorrect storage of canisters and washing of equipment.

Once present on these surfaces pesticides are then available to be washed into anadjacent watercourse or to enter the sewerage system, which then transports them tothe sewage treatment works and on into the aquatic environment via the worksdischarge. Direct contamination of the aquatic environment can also occur as the resultof spray drift or when pesticide application is inaccurate and occurs outside the con nesof the target eld.

Standards for the use and management of pesticides in the UK are set out by BASIS andthe Health and Safety Executive and, in 2001, the farming and crop protection industryestablished the Voluntary Initiative to promote best practice in the use andmanagement of pesticides and to minimise their environmental impacts.

T V un I i ia The Voluntary Initiative (VI) began in April 2001. It is a UK wide package of measures,agreed with Government, designed to reduce the environmental impact of the use ofpesticides in agriculture, horticulture and amenity situations. Initially a list of 27proposals, the programme nally included over 40 di erent projects coveringresearch, training, communication and stewardship.

C SE S Y

The combined cost of the programme between 2001 and 2006 to the farmingindustry, the crop protection industry, the water industry and others was estimated tobe £45 47m, but during that time they worked to:

Improve awareness among farmers of the potential environmental risks arisingfrom pesticide use; improve the competence of advisors and improve eldpractices of spray operators and optimise the performance of their machines.

Engage the farming unions and establishment of Crop Protection ManagementPlans (CPMPs) as a self audited means of assessing and planning theenvironmental aspects of crop protection activities across the whole farm.

Establish a low cost sprayer testing scheme (NSTS) with a nationwide network of294 testing centres and 465 certi cated testers.

Establish the National Register of Spray Operators (NRoSO), through which sprayoperators can demonstrate a commitment to best practice in pesticide handlingand application.

Create a series of Environmental Information Sheets as an aid to risk managementfor all products sold by members of the Crop Protection Association.

There are a number of comprehensiveguides on good/best practices to beundertaken when using pesticides,including the Code of Practice for UsingPlant Protection Products (below).

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Perhaps the simplest method for the reduction of point source pesticide pollution is toreduce the number of sprayer lling and cleaning actions undertaken by encouragingfarmers to share the use of spraying equipment. In addition, numerous studies havefound that the adoption of good or best practices when using pesticides can ensure thatthe risk of environmental contamination is minimised (Kreuger and Nilsson, 2001).

The best management practices shown to be e ective include lling and cleaningsprayers only on the eld or on a biobed (Felgentreu and Bischo , 2006; Vischetti et al.,2004), careful handling and storage of pesticides and safer storage of empty containers(Higginbotham, 2001), applying tank mix and container leftovers in dilute form to theeld (Jaeken and Debaer, 2005), and no application of pesticides on the farmyard.

Overall, stewardship initiatives and application of best management practices havebeen shown to achieve a reduction in the total river load of 40–95% in a number ofcatchment studies (Reichenberger et al., 2007; Kreuger and Nilsson, 2001; MailletMezeray et al., 2004). However, in most catchment studies, it was also found thatcontinued e ort is essential to ensure continued prevention.

Another powerful method for the collection and disposal of pesticide contaminatedwater is the biobed. A biobed consists of a pit or container lled with a mixture ofchopped straw, peat and topsoil that rapidly degrades any pesticide entering the bedthroughmicrobial activity.

C SE S Y

A pesticide handling area is the sitewhere the sprayer is lled and is oftenalso used for sprayer washing, nozzlecalibration, sprayer testing,maintenance and storage.

A biobed is a mixture of peat freecompost, soil and straw (biomix)covered with turf that is placed in alined pit (see right).

Liquids enter the biomix within thebiobed by gravity drainage or a pump.Once there they then undergobioremediation before being drainedfrom the biobed. This drained liquid,which contains minimal pesticideresidues, can be used for land irrigationor re used e.g. for subsequent sprayerwashing.

Mi i a ng e i id p i Re , C w l Over the period 1996 2010, South West Water’s Drift Water Treatment Works recorded a steady increase in both thenumber of pesticide detections per annum and the detected concentration of individual pesticide compounds in both theraw and nal water. During this period there were 54 positive detections for pesticides in the raw water within DriftReservoir representing 14 di erent compounds.

The chart below shows that, in recent years, herbicide detection results for a number of chemical compounds haveshown discrete high, narrow spikes indicative of individual pollution incidents. This increasing risk and frequency of waterquality failure has led South West Water to take a two pronged approach at Drift. First, an advanced water treatmentplant was installed at the treatment works, with a capital cost of £4 million and an annual running cost of £30,000, inorder to ensure the nal water met DrinkingWater Inspectorate standards.

Concurrently, funding of £100,000 wasinvested in a programme of landownerengagement, agricultural training, andfarm intervention work upstream ofthe reservoir, to address these risingchemical detections at source. Theseinterventions are being delivered in thecatchment through Cornwall WildlifeTrust’s Wild Penwith Project, which isworking in partnership with SouthWest Water to provide landownersacross the Drift catchment with anumber of advisory, educational andinfrastructure improvement measures.

Continued over page...

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Mitigating pesticide pollution in Drift Reservoir, Cornwall...continued….

Cornwall Wildlife Trust’s Wild Penwith project is working in partnership with South West Water to provide landownersacross the Drift catchment with:

One to one farm advisory visits, including an assessment of current farm practices, and provision of water protectionbest practice;

Free agricultural training events, such as weedmanagement;

A capital grant award, funding, for example, improved pesticide handling and storage areas.

In February 2013, Wild Penwith ran a weed managementtraining day on a dairy farm adjacent to Drift Reservoir.Following presentations on the cultural, mechanical andchemical control of weeds, local farmers visited the watertreatment works at Drift to learn more about thecomplexities of drinking water treatment.

Peter James, who farms at Little Sellan adjacent to DriftReservoir said, “As a farmer, I am very pleased that SouthWest Water is taking this proactive approach in our rivercatchment. We are now more aware of both the watercompanies business, and how important our activities on thefarm are to the drinking water treatment process. I believeworking in partnership in this way will be of bene t toeveryone.”

These farm activities are supported by a comprehensiveprogramme of water chemistry sampling (monitoringherbicides, insecticides and fungicides) on the reservoir’s twofeeder streams. Water samples are regularly collected withthe consent and co operation of each landowner involved.

Follow up samples can be taken from a wider network ofadditional farms as required. Using this system, the source ofany in reservoir or in river pesticide detection can be tracedback to individual farm holdings and advice and guidancegiven to mitigate the problem.

Land managers are then made aware of the drinking water issues, and o ered one to one water protection best practiceadvice and other farm interventions from the Wild Penwith team as appropriate. In addition to this chemical monitoringprogramme, biological monitoring has also been undertaken in the catchment, including the assessment of macroinvertebrates, macrophytes (large aquatic plants) and diatoms (benthic algae).

Minimising the levels of pesticides found in the rawwater could result in South West Water savings ontreatment plant operating costs. Wider environmentalgains include improved wetland and stream habitatquality, and associated enhanced biodiversity.

This is a fantastic example of South West Water’s‘Upstream Thinking’ project working to deliverimproved water quality in a small reservoir catchment.

Through the wider Wild Penwith Living Landscapeproject, Cornwall Wildlife Trust sta gained the respectand trust of local farmers, which enables them to tacklethese important drinking water quality issues together.

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Further info:www.cornwallwildlifetrust/wildpenwith

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Landmanagement & soil adviceIt has been widely demonstrated that any improvements in soil or land management,such as implementation of conservation tillage techniques, that reduce the risk of runo and soil erosion are also likely to reduce the risk of a pesticide being mobilisedfollowing its application to the land. In addition, the incorporation of organic materialinto the soil has also been shown to increase the sorption of some pesticides; reducingtheir mobility and the likelihood that they will be lost through leaching.

Interestingly, several studies have shown that the presence of sub surface land drainagealso reduces the loss of pesticides through surface run o . This nding is supported byhose of a study of autumn applied pesticides on clay loam soils in north east Englandwhere losses from an un drained plot were found to be up to 4 times larger than from amole drained plot (Brown et al., 1995).

In contrast to these ndings, however, it is also important to note that there isconsiderable evidence that over e cient drainage may also generate signi cant loss ofpesticides through leaching and drain ow. The risk factors that lead to pesticide lossthrough leaching and drainage are poorly understood, but it seems that activeingredient mobility, application rate, soil type and rainfall may all contribute to thegeneration of pollution via this route.

Where pesticide loss via drainage is considered a threat, the use of collection ponds orwetlands at the out ow are just two measures that could work to mitigate the risk thata receiving watercourse will be contaminated.

Landuse change & the improvement of farm infrastructurePerhaps the most studied interventions for the mitigation of di use pesticide pollutionare bu er strips around elds (conservation headlands), riparian bu er strips andconstructed wetlands.

These features not only reduce the risk of spray drift contaminating adjacent habitatsand watercourses, but they also act to disconnect pesticide pollution pathways bypromoting the in ltration of run o waters carrying them into aquatic environments.

C SE S Y

B S p f e i id p i i i a i As we have described for nutrient and sediment pollution, the e cacy of bu er strips in reducing pesticide losses towatercourses has also been the subject of a signi cant body of research (mainly at plot or eld scale). The ndings of thisresearch, summarised below, indicate that bu er strips can be highly e ective in mitigation of pesticide pollution.

In one of the most comprehensive reviews undertaken on the e ectiveness of bu er strips in the mitigation of pesticidepollution, Reichenberger et al. (2009) summarised the ndings of 14 publications that between them assessed theperformance of 277 di erent bu er strips. The pesticide load reductions for active ingredients in solution (below left, 63data points) and bound to sediment (below right; 214 data points) are summarised below.

Overall, bu er strips of all widths were found to be e ective in the mitigation of pesticide loss from elds and wereespecially e ective when they were vegetated and when run o ow was slowed su ciently to enable water in ltration.

PESTICIDES

Riparian bu er strips and ‘conservationheadlands’ can reduce pesticidedamage to adjacent natural habitats.

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I B S & A IT S

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MI B S & PA IT S Two principal bacterial groups, coliforms and faecal streptococci, are used as indicatorsof possible sewage contamination in water because they are commonly found in humanand animal faeces. Although these bacteria, which are often referred to as faecalindicator organisms (FIOs), are not typically harmful themselves, they do indicate thepossible presence of pathogenic (disease causing) bacteria, viruses, and protozoansthat also live in human and animal digestive systems.

Another group of microbial pollutants derived from human and animal faecal materialwhich pose a signi cant risk to human health, either when people come into contactwith the river water or when contaminated water is abstracted for drinking watertreatment, are parasitic protozoa in the genus Cryptosporidium.

Cryptosporidium is transmitted through the environment as hardy spores (oocysts) that,once ingested, hatch in the small intestine and result in an infection of intestinalepithelial tissue. The resulting condition, Cryptosporidiosis, is typically an acute shortterm diarrheal disease but it can become severe and chronic in children and in othervulnerable or immuno compromised individuals. In humans, Cryptosporidium canpersist in the lower intestine for up to ve weeks; from where it continues to shedoocysts into the environment.

S u e i i l c n na i The most commonly tested faecal bacteria indicators are total coliforms, faecalcoliforms, and faecal streptococci. Total coliforms are a group of bacteria that arewidespread in nature and which occur in manymaterials including human faeces, animalmanure, soil, and submerged wood. The usefulness of total coliforms as an indicator offaecal contamination therefore depends on the extent to which the bacteria speciesfound are faecal and human in origin.

For recreational waters, total coliforms are no longer recommended as an indicator, butfor drinking water, total coliforms are still the standard test because their presenceindicates contamination of a water supply by an outside source.

Faecal coliforms are a subset of the total coliform bacteria and are more speci callyfaecal in origin. Faecal streptococci also occur in the digestive systems of humans andother warm blooded animals. In the past, the ratio between the level of faecalstreptococci and faecal coliforms was used to determine whether bacterialcontamination was of human or nonhuman origin and, while no longer recommendedas a reliable test, this method can still give an indication of the potential source.

There are three principle mechanisms via which faecal material, parasites and faecesderived substances (e.g. ammonia) make their way into a watercourse. These include:

Direct ‘voiding’ into the water by livestock in the river.

Wash o and leaching of manure or slurry on the land surface or accumulated onyards or tracks.

From consented or un consented discharges of untreated human sewage.

Cryptosporidium oocysts under auorescence microscope.

Bacteria Escherichia coli.

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When considering microbial contamination is it important to examine the contributionthat these di erent potential sources make to the load in the water column in anyparticular location.

Analysis of data from 205 river and stream sampling points spread widely acrossmainland UK has shown that microbial load is typically correlated with high ow ratherthan low ow condition and that urban and grassland landscapes make the mostsigni cant contribution to the load (Kay et al., 2009).

Further studies have also shown that faecal indicator organism (FIO) loads incatchments with high proportions of improved grassland were shown to be as high asfrom urbanised catchments and in many rural catchments 40% of FIO may be derivedfrom agricultural sources (land surface and farmyard infrastructure).

This strong correlation between high ow and contamination levels has also beenshown to be the case for cryptosporidium and outbreaks of cryptosporidiosis arestrongly linked to an animal to human transmission pathway following periods of heavyprecipitation (Lake et al., 2005).

It is assumed that the remaining load at times of high ow is derived from point sourcessuch as sewerage treatment works, misconnections in the sewerage system andcombined sewer over ows (which discharge when sewage treatment works reach theirmaximum treatment capacity).

Interestingly, in contrast to these ndings of Kay et al, a detailed study of the RiverRibble catchment undertaken in 2002 found that over 90% of the total FIO loadentering the Ribble Estuary was discharged by sewage related sources during high owevents.

At times of low ow the principal sources of FIOs has been shown to be from pointsources, such as sewage treatment works, septic tanks and misconnections in thesewerage system.

I pac i i l c n na i On the health of aquatic ecosystemsWhen animal and human faecal material and the microbes it contains, enter a riversystem they can exert severe negative impacts on the ecological health of theecosystems locally and further down the catchment in a number of ways.

First, the elevated levels of turbidity reduce the levels of light penetrating the watercolumn and this can a ect the plant communities present in the system. This can beparticularly problematic in the deeper and ecologically sensitive waters of the estuariesand coastal regions at the bottom of a river catchment.

More signi cantly, however, is the e ect that the metabolic activity of aerobic bacteriadecomposing organic waste has on the levels of dissolved oxygen in the water column.

Where the levels of organic material and hence the microbial activity in the water arehigh the Biological Oxygen Demand (BOD) in the water will be elevated and the levelsof dissolved oxygen available for other plants and animals living in the water will fall.

Eventually this depletion of dissolved oxygen will become so severe that the ecologicalhealth of the river ecosystem will be degraded as sh and invertebrate communitiesbegin to su er.

Unrestricted access of livestock to a watercourse

eutrophication&hypoxia

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On the provision of drinking water, recreation & sheriesThe total level of microbial contamination in water and the level of di erent faecesderived bacteria are both used as indicators of the potential pathological risk posed bythat water. In addition, faecal material may also contain other pathogenic organisms,such as Cryptosporidium, which cause gastrointestinal infections after ingestion orothers which cause infections of the respiratory tract, ears, eyes, nasal cavity and skin.

When animal and human faecal material enter a river system they can therefore pose asigni cant threat to the health of people who rely on that water for drinking water,recreation or the sustenance of sheries and shell sheries in downstream regions of theriver catchment.

As a result of this threat, signi cant steps must be taken at the water treatment worksto remove microbial contaminants from drinking water. There are a number of methodsfor the disinfection and ltration of drinking water and all must be undertaken withincreased intensity if the microbial load in the abstracted raw water increasessigni cantly at certain times.

The EC Drinking Water Directive also requires that drinking water should not containany micro organism or parasite (such as Cryptosporidium) at a concentration that wouldconstitute a potential danger to human health. Cryptosporidium is particularly adept atbreaking through the standard suite of treatment processes undertaken at many works(such as sand ltration and chlorination) and the Drinking Water Inspectorate nowrequires water companies to implement raw water monitoring, to undertakecomprehensive risk assessments and to design and continuously operate adequatetreatment and disinfection for cryptosporidium.

In addition to these increased demands for disinfection, it is also important to note thatthe presence of elevated levels of faecal material also make a signi cant contribution tothe turbidity and suspended solid load in the raw water. As already described previouslythe levels of turbidity in the raw water are used to calibrate the water treatment processand, when elevated, will increase the costs of coagulation and sludge managementprocesses undertaken at the drinking water treatment works.

C SE S Y

Ba ng wat n K The European Union began work to regulate the provision of clean and healthy bathingwaters in the 1970s and in 2006 the EC Bathing Water Directive was passed to preserve,protect and improve the quality of the environment and to protect human health.

The monitoring and improvement of water quality at bathing waters that are at risk offailing the standards set out in the European Bathing Water Directive are theresponsibility of the Environment Agency. They take weekly water samples from over500 coastal and inland bathing waters in England and Wales during the bathing season(May to September).

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 whenpathogenic microbes may be present in the water.

Prior to 2012, water samples taken at bathing waters were analysedfor Total coliforms, Faecal coliforms and Faecal streptococci; howeverthis has changed in preparation for the revised bathing waterdirective, which sets more stringent water quality targets to achieveby 2015.

In addition to improving water quality at bathing waters the revisedDirective also places much greater emphasis on managing beachesand providing information. From 2016, Bathing Water Controllers (anylocal authorities, water companies and businesses in control of theland immediately next to bathing waters where people swim) will alsohave to provide information to the public about the quality of theirbathing water and advise people if there has been a pollution incident.

Cryptosporidiosis (the Cryptosporidiumpathogenic lifecycle) (top) and amicrograph showing cryptosporidiumoocysts alongside Giardia lamblia(another parasite) (bottom).

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Mi i l i i a i ea ure & e ca There are numerous highly e ective methods designed to reduce the microbialcontamination of watercourses, estuaries and coastal waters. Which of these measuresis required depends entirely on the sources from which the contamination is derived in aparticular catchment.

If a domestic sewage treatment works or septic systems are found to be dischargingsigni cant levels of faecal material and bacteria into a watercourse then the addition offurther ‘tertiary’ treatment processes, such as disinfection may be required to removehigh levels of bacteria from the e uent discharged.

Where the contamination is the result of untreated e uent discharges from combinedsewer over ows (CSOs) or poorly functioning (misconnected) sewerage infrastructure,only increased sewage storage or treatment capacity at the works or investment ininfrastructural improvements may be capable of reducing these impacts. This type ofremedial work can have signi cant cost implications for the individuals or the watercompany responsible for the infrastructure (see below).

Mitigation measures for reducing microbial contamination in watercourses derived fromdi use agricultural sources include :

Reduction in livestock stocking rate

Creation of riparian bu er strips

Creation of wetlands or reedbeds

Exclusion of livestock from watercourse and provision of alternative drinkingsources for livestock

Increased slurry storage capacity

Minimise the volume of dirty water produced (clean and dirty water separation)

Increased use of solid manure

Do not apply manure or slurry to elds at high risk times

All of these measures act to either reduce the total levels of faeces contaminatedmaterial available for mobilisation on a farm, change the way that manure is stored toreduce its likelihood of mobilisation to a watercourse, prevent direct ‘voiding’ into watercourses, or disconnect the pathways via which faecal material is washed intowatercourses.

C SE S Y

T C e S P jec Before South West Water (SWW) was privatised in 1989, little had been done to protect the coastal bathing waters of theSouth West, and the region’s reputation was su ering as a result. In 1990, the UK Government adopted higher waterquality standards imposed by the European Union, making the need for change even more critical. Starting in 1992,SWW’s response to this was Clean Sweep – the largest environmental programme of its kind in Europe.

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TheWestcountry Rivers Trust farmmeasure fact sheets can be found at—http://tinyurl.com/kqpyctv.

Over an 18 year period, over £1.5 billion was invested in improving the waterquality of the South West’s bathing waters. As a result of Clean Sweep, 250crude sewage outfalls were closed and 140 individual mitigation projectswere completed.

The success of the programme was demonstrated in 2006, when for the rsttime all 144 bathing sites in SWW’s region achieved 100% compliance withthe EU mandatory standard. This was a massive improvement whencompared to the situation in 1996, when only 51% of beaches complied.

The 2007 Good Beach Guide, published by theMarine Conservation Society(MCS), stated that ‘the South West is the top performing region in this year’sguide’ and recommended over 80% of beaches in SWW’s operating region.

Since Clean Sweep ended in 2010, SWW have continued to develop theirstrategic plans for the delivery of environmental improvements andsustainability. Most recently, they have been working in partnership tolocate and remediate mis connections in Torbay, Bude and Plymouth.

More information:www.beachlive.co.uk

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C SE S Y

T b Ba ng at I n P jec Initiated and funded by South West Water in 2010 and delivered by the EnvironmentAgency working in partnership with Torbay Council, the Torbay Bathing WaterImprovement Project aims to reduce the levels of pollution in Torbay's streams andimprove bathing water quality. In particular, the project has focused on locating andremediating drainage and sewagemis connections that are leading to pollution.

The project has focused on ve resort beaches, key to the local economy, which areat risk of failing to meet the new standards set out by the Revised ECWater Directivefrom 2015. These beaches were Torre Abbey, Hollicombe, Preston, Paignton andGoodrington.

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Mis connectionsOver one hundred misconnected properties have been identi ed through theproject, which have all been discharging foul or dirty water into streams throughsurface water systems. 80% of the mis connections found have now beenresolved and connected to foul sewer.

The majority of misconnections have been residential with household extensionsand washing machines moved into garages being the most common culprits.

Commercial inputs have also been an issue; including a hotel, car wash, twocafes, a supermarket, doctors surgery, o ces and a factory. Other issues such asdog and bird fouling, waste from boats, sewerage infrastructure and counciloperations are all being looked at as part of the project.

It is estimated that the project has so far stopped approximately 5,000 cubicmetres (per annum) of polluting water entering Torbay streams and bathingwaters.

Examples of the mis connections found in Torbay that discharge either directly into awatercourse (top left) or into a surface water sewer (bottom left).

Signi cant ndingsIn one Torquay hotel a blockage in a main foul sewer line wasleading to considerable pollution of the Cockington stream.

Working with the hotel owners and South West Water, theissue was identi ed and resolved with a considerableimprovement in water quality in the stream, as shown in thechart (right).

In other locations six houses were found discharging into theTorre Abbey and Cockington Streams and a blocked privatemanhole was allowing foul water from two ats to dischargeto the sea via an un sampled surface water system.

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Working with Environment Agency contractors (ONSPOT), the project also discovered that a large factory had beenwrongly connected and was discharging most of its waste waters into the Torre Abbey Stream via a surface watersystem. The factory accommodates some 100 sta and is thought to have been polluting the stream for over ten years.

Next StepsSuch was success of the Torbay project that additionalfunding has now been secured and the focus will beextended to include two further catchments in Torbay; theTorre Abbey Stream and the Kirkham Stream, which bothremain a ected by as yet unknown pollution sources.

In addition, the project will also produce an engagementplan, designed to advise and educate both the public andtradesmen, to reduce the likelihood of further misconnections in the future. There is also be a drive underwayto share best practice from the project with other localauthorities to help improve other ‘at risk’ bathing waters inlocations such as Bude (north Cornwall) and Plymouth.Paignton Beach

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C SE S Y

Mea ure i i at i i l p i isk Methods to reduce pathogen transfers to watercourses essentially tackle aspects of source, mobilisation or delivery tothe watercourse.

Perhaps the most e ective measures designed to reduce the sources of faecal and organic material are those thatimprove the management of manure by increasing slurry storage capacity, reduce inputs of rainwater to manure storesor switch to a con ned composting system of storage.

By reducing the volume of contaminatedmaterial produced these measures enable farmers to restrict their application ofmanure to the land to dry periods, when the risk of wash o is least. They also allow farmers to keep their yards free ofcontaminatedmaterial and reduce the levels of live bacteria in the manure before it is spread.

Another major source of microbial contaminants is direct ‘voiding’ by livestock while in or immediately adjacent to awatercourse.

In a 7 year study of a dairy farm, Line (2003) demonstrated that livestock exclusion resulted in a 66% reduction in thelevels of faecal coliforms in the watercourse below the farm and there is considerable additional evidence that exclusionof livestock from water courses and the provision of alternative drinking points can signi cantly reduce contributionsfrom this source (see table below).

The nal type of intervention that can mitigate delivery of microbial contaminants to watercourse are riparian bu erstrips and constructed wetlands that act to disconnect pollution pathways carrying material washed o the land surface.The ability of these measures to disconnect run o has already been described in detail, but there have been a number ofstudies that have investigated their ability to reduce bacterial loads at eld and plot scale (summarised in table below).

Reference Location Bu er Width (m) Soil Texture Slope (%)E cacy

(% FIO reduction)

Atwill et al. (2002) USA 3.1 Sandy loam 5 20 99.9

Lim et al. (1998) USA 6.1 Silt loam 3 100

12.2 100

18.3 100

Muenz et al.(2006) USA 25 Sandy clay loam 16.5 53

Tate et al. (2004) USA 1.1 Sandy loam 5 20 75 88

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COL R , STE & OD R C S

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COL R, STE & OD R There are a number of factors that may result in water exhibiting aberrations in itscolour, taste or odour and which negatively a ect its quality and/or safety. On mostoccasions when colour, taste or odour problems do occur the impacts are primarily onthe aesthetic quality of the water and therefore, with the resulting increase in the risk ofwater customer dissatisfaction, there is an increase in the intensity and cost oftreatment required to remove it from the water.

In addition, however, there are occasions when soluble colour, taste and odour causingcompounds occur which can pose a serious threat to the condition of water supplyinfrastructure and, in some circumstances, to human or ecosystem health.

Perhaps the best examples of this are metal ions which, in addition to causing aestheticproblems in the water, can have signi cant impacts on the ecological condition of riversand streams.

S u e c u , a t & o u c p un There are two main groups of soluble species that can cause colour, taste and odourproblems, namely metal ions and soluble organic compounds (a component of dissolvedorganic carbon—DOC).

These compounds (described in the table below) are often derived from natural sourcesin the environment, such as the underlying geology, or through the natural breakdownof organic material. However, in certain circumstances their levels can be arti ciallyelevated as an indirect result of human activities or as a direct bi product of the watertreatment process itself.

Soluble species Sources Impacts

Metal ions

Aluminium Natural release from underlying geology andbi product of water treatment coagulationprocess.

Can cause discolouration of water. Evidence suggests theremay be some health and ecological impacts of chronic exposure.

Copper Naturally occurring, but can be mobilised asa result of human activity.

Can cause metallic taste and can lead to the discolouration ofsupply infrastructure. Evidence suggests there may be somehealth and ecological impacts of chronic exposure.

Iron Naturally occurring, but can be mobilised asa result of human activity.

Can cause metallic taste and can lead to the red/brown discolouration of supply infrastructure. Evidence suggests there maybe some ecological impacts of chronic exposure.

Manganese Naturally occurring, but can be mobilised asa result of human activity.

Can cause metallic taste and can lead to the black/brown discolouration of supply infrastructure. Evidence suggests there maybe some ecological impacts of chronic exposure.

Zinc Naturally occurring, but can be mobilised asa result of human activity.

Can cause metallic taste. Evidence suggests there may be someecological impacts of chronic exposure.

Organic compounds

Geosmin Produced by aerobically growing aquaticalgae and microbes. Also produced by lamentous actinomycete bacteria in soil.

Cause earthy taste and odour problems in drinking water thatare very hard to remove without activated carbon ltration.

Methyl Isoborneol(MIB)

Produced by aerobically growing aquaticalgae and microbes. Also produced by lamentous actinomycete bacteria in soil.

Cause earthy taste and odour problems in drinking water thatare very hard to remove without activated carbon ltration.

Trihalomethanes(THMs)

Produced as a bi product of chlorinedisinfection of drinking water containingorganic material.

Growing evidence that THMs are carcinogenic. Very hard toremove without activated carbon ltration.

Humic substances Produced by biodegradation of dead organicmatter (e.g. peat, woodland, algae etc.)

Discolouration of water (yellow) that is very hard to removewithout activated carbon ltration.

Can reduce e ciency of other treatment processes.

Ferric (iron based) compounds leach into a stream (top) and heavily colouredwater in the upper reaches of the RiverDart (bottom).

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The drainage and over exploitation of peat bogs and other upland habitats with peatbased soils, is known to enhance the loss of dissolved organic carbon (DOC) towatercourses and to signi cantly increase water discolouration through contaminationwith colour causing organic compounds such as humic acids (Worrall et al., 2007;Wallage et al., 2006; Armstrong et al., 2010).

In addition to the colour causing compounds derived from peat and peaty soils, it hasalso been shown that leaf litter is another important source of natural dissolved organiccarbon (DOC) in forested catchments (Hongve, 1999). Interestingly, rainwaterpercolating through fresh litter is known to obtain higher concentrations of DOC andcolour than is derived from older forest oor material and organic soils. Furthermore,deciduous leaf litter has been shown to impart high DOC concentrations in the autumn,while coniferous litter and organic soils release DOCmore evenly.

In their Advisory Note 19 on, ‘Rivers and their catchments: potentially damaging physicalimpacts of commercial forestry’, Scottish Natural Heritage warn that ploughing andrestructuring of drainage patterns may occur as part of ground preparation work prior tocommercial tree planting. They also describe how drainage ditches are often aligned atright angles to the slope, which causes peak run o ows to arrive more rapidly in thereceiving watercourse.

The e ect of this drainage, coupled with the increased availability of colour causingcompounds in the soil due to the decomposition of leaf litter and the degradation of thepeat, could be the cause of the deteriorations in water quality now commonly observedin many watercourses and reservoirs in upland catchments.

Other organic taste and odour causing compounds that are generated in soil anddecomposing organic material are geosmin and 2 Methylisoborneol (MIB). Thesecompounds are also generated within many lakes and reservoirs as algal andmacrophyte growth dies back at the ends of the growing season (see right).

Many colour causing metals, such as iron, zinc and manganese, are released naturallyfrom land with underlying geology where they occur and they can therefore be leachedat quite signi cant levels into watercourses. This leaching can be signi cantly enhancedwhere geological disturbance has been caused through human activities such as mining.

It has also been shown that upland peaty soils, with their inherently acidic nature,particularly favour the mobilisation of manganese and, furthermore, conifera orestation has also been demonstrated to increase manganese levels in surfacewaters immediately following felling.

In addition to being catchment derived, manganese ux in lakes or reservoirs can alsooccur as a result of seasonal strati cation occurring in eutrophic waterbodies.Manganese ions are mobilised into solution from lake bed sediment when an hypoxic/anoxic layer of water forms above it and, once solubilised, are then distributedthroughout the waterbody when re mixing of the water column occurs in the autumn.

This phenomenon results in large spikes of these manganese ions in solution at varioustimes (see right) and can then present a signi cant challenge to the ecological health ofthe aquatic environment and to the water treatment process.

Humic acids (top) are known to bereleased from degraded peatland(bottom).

Data showing large seasonalaccumulations of geosmin (top) andmanganese (bottom) in a smallreservoir in the SouthWest of England.

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I pac c u , a t & o u c n n n On the health of aquatic ecosystemsThe ecological impacts of taste and odour causing organic compounds (dissolvedorganic carbon) remain poorly understood, but their ecotoxicology has beeninvestigated in a number of experimental systems and few toxic e ects have beendemonstrated at the concentrations typically found in contaminated waterbodies.

In contrast, several metal ions have been shown to have an impact on the ecologicalhealth of aquatic ecosystems. As a result of these ndings chromium, copper, iron andzinc are all listed as ‘speci c pollutants’ and have standards monitored as part of theecological condition assessments undertaken for the Water Framework Directiveclassi cation process. The inclusion of manganese as a speci c pollutant in the nextcycle of Water Framework Directive classi cation is currently being considered.

On the provision of drinking waterThe levels of colour, taste and odour compounds in raw water have a direct impact onthe dose of coagulant required in its treatment at the water treatment works (indeedmany works dose coagulant according to turbidity and colour levels in the raw water). Ifthese compounds are not removed they can impinge on the aesthetic quality of the naldrinking water and cause the discolouration of drinking water infrastructure (forexample manganese in treated water can stain sanitary ware).

In addition, soluble organic compounds, such as humic substances and geosmin, cancause further problems at the water treatment works as they can be converted intodisinfection by products (DBPs) when chlorine is used during water treatment process(Krasner et al., 1989).

These DBPs can take the form of trihalomethanes (THMs), haloacetic acids (HAAs) anda host of other halogenated DBPs, many of which have been shown to cause cancer inlaboratory animals and which can pass though the standard treatment processesundertaken at many works (Singer, 1999; Rodriguez et al., 2000).

C SE S Y

C u F w Re , Increasing levels of colour in the water from Fernworthy Reservoir on theeastern edge of Dartmoor represent a signi cant challenge for South WestWater at the Tottiford water treatment works. The deterioration in the waterquality in the reservoir was so severe that the Bovey Cross water works had toclose because the treatment process could not cope with the raw water. Thecolour causing compounds in Fernworthy Reservoir are primarily humicsubstances derived from the degradation of organic material in the peat landsand forested areas that surround this moorland reservoir (see land cover map;right). It is clear that water percolating through peat or forest leaf litter acrossthe catchment is mobilising and transporting these colour causing substancesinto the watercourses and drains that feed into the reservoir. This e ect isbeing signi cantly enhanced in areas where the peat has been damaged ordegraded through drainage or intensive exploitation.

Humic colour causing compounds in raw water can only beremoved through the coagulation process at the works andso, if the colour levels in the water increase, it can havesigni cant cost implications for the water company as thecoagulant dose must also be increased. These organiccompounds cause further problems at the works as theycan be converted into disinfection by products (DBPs)when chlorine is used during water treatment.

Examination of South West Water data (left) shows thatthe level of colour in Fernworthy Reservoir cyclesthroughout the year, but also that the average level hassigni cantly increased since 2004.

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C u , a t & o u i i a i ea ure Ultimately, the only way to completely remove the soluble organic compounds andmetal ions that cause colour, taste and odour problems in raw water intended fortreatment and supply as drinking water is to implement technological solutions, such asactivated carbon lters, at the treatment works.

Whether they are derived from point or di use sources in the catchment, mitigation oftheir loss into the aquatic environment at their source is far more challenging to achieve.

Having said this, however, there is increasing evidence that re wetting of peat lands andmires that have been degraded by drainage or over exploitation of peat can reduce theleaching of Dissolved Organic Carbon (DOC) compounds that cause colour, taste andodour contamination of raw water.

Speci cally, several studies have demonstrated that the re wetting of mires and peatlands, through the practice of drain blocking, can signi cantly reduce the loss of DOCand colour causing compounds from land of this type (Wallage et al., 2006; Armstronget al., 2010).

In their extensive UK wide survey of blocked and unblocked drains across 32 study sitesand through the intensive monitoring of a peat drain system that has been blocked for 7years, Armstrong et al. (2010) demonstrated that dissolved organic carbonconcentrations and water discolouration were signi cantly (~28%) lower in blockeddrains compared to unblocked drains.

Overall, whether the source of contamination is from mine works, forestry or peatlandsoils it is clear that it is the management of drainage and the hydrological regime of theland which may achieve the greatest e ect in mitigating the impacts of colour, taste andodour causing contaminants.

C SE S Y

T S n Ca n M na n P o (SC P) The Sustainable Catchment Management Programme (SCaMP), has been developed byUnited Utilities in association with the Royal Society for the Protection of Birds (RSPB).The programme aims to apply an integrated approach to catchment management acrossall of the 56,385 hectares of land United Utilities own in the North West, which they hold toprotect the quality of water entering the reservoirs.

Through the delivery of SCaMP United Utilities is recognised within the UK water industryas being at the forefront of water company funded catchment management scheme thatare aiming to secure multiple bene ts at a landscape scale.

Peatland restoration being undertakenby the Exmoor Mires Project (top) andstakeholders visit a restored mires site(bottom)

The aims of the SCaMP initiative are to help; (1) protect andimprove water quality, (2) reduce the rate of increase in rawwater colour which will reduce future revenue costs, (3)reduce or delay the need for future capital investment foradditional water treatment, (4) deliver government targetsfor SSSIs, (5) ensure a sustainable future for the company'sagricultural tenants, (6) enhance and protect the naturalenvironment, and (7) help these moorland habitats tobecomemore resilient to long term climate change.

Monitoring at a sub catchment level in SCaMP delivery areas indicates that there is a statistical ‘tipping point’ two yearsafter intervention. This has been found in similar short term studies and it is thought that re wetting dried peat initiallyreleases more carbon in the form of colour before the natural biochemical processes begin to re establish. At presentseveral sub catchments are indicating a slight, but statistically signi cant, decrease in colour over time and one sitehas seen a signi cant 45% reduction in stream ow turbidity since restoration.

For more information visit—corporate.unitedutilities.com/scamp index.aspx

Over the last 30 years there has been a substantial increase in the levels of colour in the water sources prior to treatmentfrommany upland catchments (see example below). The removal of colour requires additional process plant, chemicals,power and waste handling to meet increasingly demanding drinking water quality standards. To address this, expensivecapital solutions are often required at a water works which result in signi cant increases in annual operational costs.

COLO

UR,TA

STE&ODOUR

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S S P V M N S N P V M N S N

WATER QU LI YWATER QU LI Y

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The principal, over arching aim of any catchment management work is to improve thewater quality in our freshwater ecosystems and to make a signi cant contribution totheir attainment of good ecological status in accordance with requirements of the EUWater Framework Directive. It is therefore vital that su cient evidence is collected toprovide an objective and robust assessment of the improvements delivered.

Ultimately, we must be able to justify that the money spent and the interventionsdelivered across the landscape have delivered signi cant improvements in water quality(and have therefore made signi cant contributions to the delivery of good ecologicalstatus of river catchments) and have generated signi cant secondary nancial,ecological and social bene ts.

To achieve these over arching aims, a range of approaches have been developed thatwill allow us to assess various outcomes delivered by our catchment management work;

Quanti cation of intervention delivery. Gathering precise and detailed evidence ofwhat has been delivered, where and how it was delivered, what it cost and, perhapsmost importantly, what the intended outcome was for each measure.

Monitoring for environmental outcomes. Collection of a comprehensive and robustset of data and evidence which demonstrates qualitatively and quantitativelywhether real improvements in raw water quality have been achieved. To achieve thisit is vital that this includes robust baseline data that includes temporal (beforeintervention) and spatial (no intervention) controls.

Modelling to predict environmental outcomes. Use of the most advanced modellingtechniques which can be used to estimate the improvements in water quality thathave been achieved.

Assessment of secondary outcomes. There are a number of monitoring andmodelling approaches that can be used to assess how a catchment managementprogramme has enhanced the provision of other ecosystem services across acatchment and to quantify the economic bene ts to those engaged in the process.

A S I P V M N S

T EF A n a i Te Ca n ( TC) As part of a national drive to gather evidence that catchment management can have a signi cant impact on raw waterquality DEFRA are currently funding a £5 millionDemonstration Test Catchment (DTC) Project across three catchments:the Hampshire Avon, the Wensum and the Eden. The aim of DTC Projects is to evaluate the e ectiveness of on farmmeasures to improve water quality when their delivery is scaled up to a real life whole sub catchment situation. .

The Westcountry Rivers Trust’s current Upstream Thinking Project on the Caudworthy Water, a short (~3.5 km)tributary of the River Ottery in the Tamar catchment, now represents a satellite study of the Hampshire Avon DTC. TheDTC consortium is undertaking a detailed monitoring programme before and after the a comprehensive farminvestment and advice programme being delivered across the catchment.

C SE S Y

Two monitoring stations located at the middle and bottom of the catchment havebeen recording total nitrogen, nitrate, nitrite, soluble reactive phosphate, totalphosphate, turbidity, suspended sediment concentration, dissolved oxygen,temperature, pH, ammonium, chlorophyll, e ective particle size and discharge.

In addition to this chemical monitoring programme, extensive biologicalmonitoring has also been undertaken in the catchment, including the assessmentofmacro invertebrates, benthic algae (diatoms),macrophytes and sh.

The baseline data for Caudworthy Water has been collected over an 18 monthperiod and Westcountry Rivers Trust have approached all twenty four farmers inthe Caudworthy Water sub catchment. To date, over £450,000 has been investedin around £700,000 worth of capital investments with Best Management Practicesensured through the application of a Restrictive Deed on 19 of these farms.

Following the implementation of the Best Management Practices in 2012 13, thee ects on water quality will then be monitored over 2013 15.

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C SE S Y

T E t nde E p C e n Mod l (E M+) The Extended Nutrient Export Coe cient Model (ECM+) has beendeveloped by the University of East Anglia under the Rural Economy andLand Use (RELU) Programme and part funded by the Westcountry RiversTrust. This model has been reviewed by scienti c peers and the DEFRAWater Policy Group and is widely expected to become one of the primarymethods for rural land management planning through stakeholderparticipation in the future.

ECM+ has been developed to predict the e ects implementation of BestManagement Practices (BMP’s) (Cuttle et al. 2007) will have on sediment,faecal indicator organisms (FIOs), phosphorus and nitrogen inputs intowatercourses.

Put simply, the model uses export coe cients for di erent land use types tocalculate exports of these pollutants based on the following input data:

Landuse distribution—including urban and various agricultural landusessuch as cereals, maize and grassland.

Livestock numbers—including numbers of cattle, sheep, pigs and poultry.

Population served, treatment levels and locations of Sewage TreatmentWorks (STWs)

Population not served by STWs—indicative of septic tank numbers

Road and track density

Rainfall and hydrological data combined with information on in streamprocessing of pollutants

Location and area of lakes and reservoirs with modelled impact on pollutantload at out ow

Farming practices: current uptake of Best Management Practices ande ectiveness in reducing pollutant export

What makes the ECM+ model such a powerful tool is that it is constructed with the participation of farmers, watercompany representatives and other stakeholders in the catchment and this allows all of the input data to be ‘groundtruthed’ before it is added into the model. In addition, the model is calibrated at the sub catchment level with real world,in streammeasurements of pollutant load derived from Environment Agency monitoring data.

Another important component of the ECM+ model is that, once it has been built, it is then possible to develop and run anumber of scenarios with the stakeholders (which can include di erent blends of both Best Management Practices onfarms and improved sewage treatment measures) and observe their e ects on the export of pollutants to thewatercourse.

ECM+ in ActionThe River Tamar is a key raw water source for South West Waterand has been the subject of considerable investment in catchmentmanagement interventions through schemes such as UpstreamThinking and Catchment Sensitive Farming.

The Caudworthy Water sub catchment of the River Ottery in theTamar catchment is also a satellite study site for the DEFRADemonstration Test Catchment (DTC) project on the HampshireAvon.

In light of its importance as a drinking water catchment and for theWater Framework Directive (the Crownhill WTWs catchment iscomprised of 45 WFD waterbodies) the ECM+ model has been builtfor the River Tamar catchment above its tidal limit at Gunnislakethrough a participatory development process.

Once built, the model has then be used to predict the improvements in water quality that may have been achievedthrough the delivery of di erent catchment management scenarios in di erent locations.

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This case study summarises the ECM+ predicted export of nitrate and phosphate from the Tamar catchment under fourdi erent management scenarios, involving di erent levels of implementation of the top 35 (most commonly used) BestManagement Practices. The four scenarios were as follows:

Scenario 1: Baseline (current situation, no additional interventions)

Scenario 2: 100% uptake of top 35 BMPs in the Caudworthy sub catchment

Scenario 3: 100% uptake of top 35 BMPs across the whole of the Tamar above Gunnislake Bridge

Scenario 4: 100% uptake of top 35 BMPs across the whole of the Tamar plus 90% nitrogen and phosphate strippinge ciency at all Sewage TreatmentWorks.

The model outputs show the predicted average concentration of each pollutant against speci c standards. For phosphate, the backgroundmatches the classi cation used for the EUWater Framework Directive: blue represents ‘high ecological status’; green ‘good ecological status’,yellow ‘moderate ecological status’, orange ‘poor ecological status’ and red ‘bad ecological status’. For nitrate, the pre abstraction standardfor drinking water is de ned by the dark blue vertical line on the far right of the nitrogen export graphs below (equating to 11.3 mg/l). Thebright blue line in the centre of the graphs represents a stringent ecological limit used in some water bodies, which translates to 2.5 mg/l.

Scenario 1: BaselineThe outputs from the ECM+ model (right) indicate that theCaudworthy sub catchment under the current ‘business asusual’ scenario (Scenario 1) is likely to have an averagephosphorous export load corresponding to moderate/poorecological status.

At Gunnislake Bridge the phosphate levels are likely to bemoderate.

Below the Caudworthy out ow and Gunnislake Bridge thenitrogen levels are likely to be compliant with the drinkingwater standard, but exceed the ecological standard in bothlocations.

Extended Export Coe cient Model (ECM+)...continued….

Scenario 2: 100% BMP uptake on the Caudworthy

In Scenario 2 (not shown), the model predicts that average water quality in the Caudworthy sub catchment will improveto better than good ecological status for phosphate and will be compliant with the more stringent ecological standard fornitrogen. The e ect of this level of action in the Caudworthy is also passed on to Gunnislake, but the improvements aremasked by the volume of water from the rest of the Tamar catchment.

Scenario 3: 100% BMP uptake on the whole Tamar catchment

In Scenario 3 (left), water quality at the Caudworthy Waterout ow and Gunnislake Bridge both improve signi cantly withnitrogen levels at both sample sites predicted to be compliantwith the stringent ecological standard.

However, phosphate levels at Gunnislake Bridge are still only 25%certain to reach good ecological status.

Scenario 4: Scenario 3 plus 90% N and P stripping at STWs

In Scenario 4, the model predicts a greater than 50% chancethat the water quality at the Caudworthy out ow andGunnislake Bridge would both meet water frameworkdirective standards for phosphorous and that nitrogen levelswould be compliant with stringent ecological standards.

ECM+ predicts signi cant improvements in water quality as a result of implementation of BMP’s. Importantly, the ECM+has been used very successfully as a method for rural land management planning through stakeholder participation.Delivering improvements in water quality through catchment management requires strong partnerships and successfulstakeholder engagement, including private, public and third sector organisations and landowners.

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C SE S Y

F c H ps r A The FARM SCale Optimisation of Pollutant Emission Reductions (FARMSCOPER)model is a decision support tool that can be used to assess di use agriculturalpollutant loads on a farm and quantify the impacts of farm pollution control optionson these pollutants.

FARMSCOPER allows for the creation of unique farming systems, based oncombinations of livestock, cropping and manure management practices. Thepollutant losses and impacts of mitigation can then be assessed for these farmingsystems.

The e ect of a potential mitigation methods are expressed as a percentagereduction in the pollutant loss from speci c sources, areas or pathways.

The tool utilises a number of existing models including:

Phosphorus and Sediment Yield Characterisation in Catchments (PSYCHIC)

National Environment Agricultural Pollution Nitrate (NEAP N)

National Ammonia Reduction Strategy Evaluation System (NARSES)

MANure Nitrogen Evaluation Routine (MANNER)

IPPCmethodology for methane and nitrous oxide.

The e ectiveness of mitigation methods are characterised as a percentagereduction against the pollutant loss from a set of loss coordinates. Thee ectiveness values were based on a number of existing literature reviews, elddata and expert judgement and are assumed to incorporate any e ciencies ofimplementation.

The e ectiveness values for mitigation methods were allowed to take negativevalues, which can represent ‘pollution swapping’, where a reduction in onepollutant is associated with an increase in another.

The tool also estimates potential consequences of mitigation implementation onbiodiversity, water use and energy use.

The Hampshire Avon Study

The Hampshire Avon is a lowland system situated on thesouthern coast of England. It is a predominantly ruralcatchment with approximately 75% of land used foragriculture. Parts of the Avon su er from ‘chalk streammalaise’ due to nutrient and sedimentation issues that arethought to primarily originate from di use agriculturalpollution. Over 50% of the waterbodies in the catchment donot achieve good ecological status under the WaterFramework Directive.

The Hampshire Avon is also one of DEFRA’s DemonstrationTest Catchments.

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Spatial datasets and the Agricultural Census returns for the River Avon in 2009 were used to develop a collection of farmtypes characteristic of the Hampshire Avon and re ective of landuse patterns, physical landscape characteristics andfarmmanagement practices in the area.

Of these representative farms, it was estimated that there were 292 cereal farms (representing 51% of the land area),129 lowland grazing farms (11% of land area), 130 mixed farms (20% of land area), 77 dairy farms (8% of land area) and 52horticultural farms (less than 1% of land area) in the Avon catchment. The remaining land area comprised small numbersof general cropping, pig, poultry or ‘other’ representative farm types.

FARMSCOPER was then used to test three di erent scenarios and estimate sediment, nitrate, phosphorous, ammonia,methane and nitrous oxide loads or emissions for each representative farm type. The scenarios tested were:

Scenario 1: Baseline pollutant emissions with nomitigation measures

Scenario 2: Current pollutant emissions based on an estimate of the existing level of mitigationmeasuresimplemented

Scenario 3:Maximum reductions through implementation of all measures in the Defra User Guide (Newell et al. 2011)

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FARMCOPER on the Hampshire Avon...continued….

ResultsFARMSCOPER predicts baseline pollutant loadings in kg per hectare per year (kg ha 1 yr 1) (see table). Under scenario 1,the baseline levels of pollutant emissions if no mitigation measure were in place, it estimated that cereal farms wouldcontribute about 55% of nitrate, 38% of phosphorous, 67% of sediment and 50% of nitrous oxide. Mixed farms wereestimated to contribute 48% of ammonia, 40% of methane and about 26% of nitrate, phosphorous and nitrous oxide.The principal contribution from dairy farms was methane emissions, contributing 32% of total methane. Thesepredictions were compared with monitored data for pollutant loads in the Avon and were considered acceptable.

Farm Type Nitrate (NO3) Phosphorous SedimentAmmonia(NH3)

Methane(CH4)

Nitrous oxide(N2O)

Cereals 4.0% 6.0% 7.8% 9.0% 0.0% 6.2%

General cropping 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%

Lowland grazing 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%

Under scenario 3, which is the delivery of themaximum reductions through implementation of allmitigation measures listed in the Defra Inventory ofMethods to Control Di use Water Pollution (Newellet al. 2011), the estimated percentage reductions inemissions for speci c pollutants were much greater,ranging from 0 to 70.8%.

Farm Type Nitrate (NO3) Phosphorous SedimentAmmonia(NH3)

Methane(CH4)

Nitrous oxide(N2O)

Cereals 4.0% 6.0% 7.8% 9.0% 0.0% 6.2%

General cropping 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%

Lowland grazing 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%

FARMSCOPER also allows the total emissions for each pollutant in kg per hectare per year (kg ha 1 yr 1) resulting fromscenarios 2 and 3 to be compared (see below).

Farm Type Nitrate (NO3) Phosphorous SedimentAmmonia(NH3)

Methane(CH4)

Nitrous oxide(N2O)

Cereals 4.0% 6.0% 7.8% 9.0% 0.0% 6.2%

Lowland grazing 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%

For improvement scenarios, FARMSCOPER predicts percentage reduction in emissions (relative to the baseline scenario)(see table). Under scenario 2, the current pollutant emissions based on an estimate of the existing level of mitigationmeasures implemented, the estimated percentage reductions in pollutant emissions ranged from 0 to 15.2%.

Farm Type Nitrate (NO3) Phosphorous SedimentAmmonia(NH3)

Methane(CH4)

Nitrous oxide(N2O)

Cereals 38 0.2 159 7 0 7

General cropping 37 0.1 117 7 0 7

Horticulture 34 0.3 247 5 0 4

Dairy 40 0.5 104 36 173 10

Lowland grazing 24 0.4 80 15 98 7

Mixed 51 0.4 95 43 90 10

ConclusionFARMSCOPER estimated that current levels of mitigation measure implementation have reduced total pollutant loadsby between 3 and 10%, as compared to a scenario where no mitigation measures were in place. It also predicted that,should there be signi cant uptake of the full range of mitigation measures, pollutant loads could be reduced further bysigni cant amounts for sediment (66%), phosphorous (47%), nitrate (22%), ammonia (30%) and nitrous oxide (16%).Case study adapted from: Zhang et al.,2012

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Sec n ca n na n It is widely accepted that the delivery of catchment management interventions willproduce a wide array of ancillary bene ts that could make considerable contributions toimproving the ecological condition of rivers and towards other economic,environmental or nature conservation targets.

Secondary environmental bene tsIn addition to determining the primary bene t obtained through catchmentmanagement interventions, it is also important for any secondary environmentalbene ts achieved to be recorded and quanti ed.

This can be undertaken using a number of survey, monitoring and modellingapproaches that assess how an intervention can enhance the provision of otherecosystem services across a catchment and to quantify the economic gains achieved byall of the groups engaged in the process.

Perhaps the most common example of this occurring is where interventions, such aswetland creation or restoration, which have been designed and targeted to enhance theregulation of water quality also play a key role in the regulation of water quantity (highand low ows). It is clear that these measures, if targeted into multifunctional areas ofland that regulate several di erent ecosystem services, are capable of enhancing theprovision of several of them.

In addition, considerable research is also being undertaken to asses the ability ofcatchment management interventions to restore ecosystem health, deliver increasedbiodiversity and for them to therefore have signi cant conservation value. In one suchstudy, undertaken by Jobin et al (2003) in Canada, it has been demonstrated that thecreation of riparian bu er strips (especially wooded ones) can signi cantly increase theoverall species richness and insectivorous bird abundance across a catchment.

Many of the on farm measures described in this review have also been shown to reducethe emission of greenhouse gases from agricultural land and there is growing evidencethat many may act to increase their sequestration. Careful targeting of catchmentmanagement measures to land areas with the greatest carbon sequestration potentialwill optimise the levels of sequestration achieved.

At a more strategic level, several groups and organisations (such as Durham WildlifeTrust, the Westcountry Rivers Trust, and many others) have developed methodologiesfor the mapping of land which contributes to the provision of ecosystem services. Whencombined together, these studies reveal that there are many multi functional areas thatplay a key role in the delivery of several ecosystem services.

These ecosystem services mapping exercises allow us to identify sections of thecatchment where these multifunctional, ecosystem services providing areas may comeinto direct con ict, and therefore be compromised by, other human activities, such asintensive agriculture or urban development.

This so called ‘ecosystem services’ approach allows us to identify where catchmentmanagement or policy level interventions designed to improve the provision of oneecosystem service (e.g. water quality) may also yield concurrent improvements in theprovision of other ecosystem services. Ultimately, this approach allows interventions tobe delivered in a targeted, integrated and balanced way that delivers the greatestenvironmental improvement for the resources available.

A brown trout from a healthy river

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Assessment of nancial costs and bene tsFor the full bene t of catchment management interventions to be assessed, it is alsoimportant for all of the parties involved (funders, deliverers, bene ciaries, landowners)to have a clear understanding of the nancial costs and bene ts of the proposedchange. For many interventions, a clear and detailed understanding of their cost ofdelivery has already been gained and, as we have described previously, the evidence fortheir environmental bene t continues to be gathered.

The key link that will need to be established, once this evidence is in place, is how theenvironmental bene ts achieved can be translated into nancial bene ts for the funder,the bene ciaries of the ecosystem service or the land managers who have implementedthe intervention (e.g. as the result of increased e ciency or reduced costs incurred).

This information will then allow the cost bene t of catchment managementinterventions to be explored in more detail. At present, the robust extrapolation of thecost bene t ratios calculated up to the sub catchment or catchment scale remains asigni cant challenge that will require careful consideration and further research.

P n f Eco y t m S vi e (P S) Payments for Ecosystem Services (PES) schemes are market based instruments that connect ’sellers’ of ecosystemservices with ‘buyers’. The term Payments for Ecosystem Services is often used to describe a variety of schemes in whichthe bene ciaries of ecosystem services provide payment to the stewards of those services. Payments for EcosystemServices schemes include those that involve a continuing series of payments to land or other natural resource managersin return for a guaranteed or anticipated ow of ecosystem services.

At present, farmers, who represent less than 1% of our society, currently manage ~80% of our countryside and arelargely responsible for the health of the ecosystems it supports. However, despite this key role for farmers in managingour natural ecosystems, they are currently only paid for the provision of one ecosystem service; food production. Theidea behind Payments for Ecosystem Services is that those who are responsible for the provision of ecosystem servicesshould be rewarded for doing so, representing amechanism to bring historically undervalued services into the economy.

A Payments for Ecosystem Services scheme can be de ned as a voluntary transaction where (1) a well de nedecosystem service (or a land use 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 serviceprovider secures ecosystem service provision (conditionality).

An example of a PES scheme: Upstream ThinkingDrinking water is a vital ecosystem service that we derive from our river catchments and there is signi cant scope forwater companies interested in the quality of the raw water they treat for supply to customers as drinking water.

South West Water’s Crownhill water treatment works in Plymouth currently treats around 55 60 million litres of watereach day and it is anticipated that over the next 20 years the demand for water in Plymouth will increase steadilytowards 100 million litres a day. In addition to this increased demand for water, there is evidence that declining waterquality in the river sources used to supply the Crownhill works could concurrently increase the costs and risks associatedwith the treatment of the raw water undertaken there.

The South West Water Upstream thinking project is a PES scheme in which the water company invests in catchmentmanagement on behalf of their customers in an attempt to avoid incurring the extra costs and risks associated withtreating low quality raw water at the works. If the average cost of treating water at Crownhill is increased by £5 permillion litres treated (~10%) due to poor raw water quality then the removal of this pressure could save over £2 million ontreatment costs over the next 20 years (at a treatment volume of 60 million litres a day).

C SE S Y

Under the current situation, where land is managedexclusively for agricultural production, only the privatepro ts from this activity are realised. By identifying whereanother ecosystem service, such as improved water quality,may be provided and by o ering either a minimum paymentto cover pro t forgone or a maximum possible paymentbased on the overall value to society, the buyer canincentivise the seller to change, or even switch, theirpractice and therefore deliver the improvements in theecosystem service they require.

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G VE N E & ST AT GIC L

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T EC at F w k rec 200 Perhaps the greatest driver for catchment management is the requirement for thecondition of UK river waterbodies to meet the quality standards set out in the EuropeanCommission Water Framework Directive 2000 (WFD, 2000). The WFD assessmentprocess, which applies to lakes, rivers, transitional and coastal waters, arti cial andheavily modi ed waterbodies, and groundwater, has set more rigorous and higherevaluation standards for the quality of our aquatic ecosystems.

The main objectives of the WFD are to prevent deterioration of the status of waterbodies, and to protect, enhance and restore them with the aim of achieving ‘goodecological status’, or ‘good ecological potential’ in the case of heavily modi edwaterbodies. Similarly, groundwater bodies need to reach a good status as they arerequired to maintain drinking water quality. The WFD aims to achieve at least goodstatus for all water bodies by 2015 or, if certain exemption criteria are met, then by anextended deadline of 2027.

The Water Framework Directive delivery process essentially occurs in three phases: (1)waterbody condition assessment to characterise ecological status, (2) investigations todiagnose the causes of degradation, and (3) a programme of remedial catchmentmanagement interventions set out in a River Basin Management Plan (RBMP).

In addition to protecting and improving the ecological condition of aquatic ecosystems,theWater Framework Directive has several further overarching aims that include;

Promoting sustainable use of water as a natural resource

Conserving habitats and species that depend directly on water

Contributing to mitigating the e ects of oods and droughts

VE N E & PL

T ca n p s p oa h In recent years it has been increasingly recognised that enhancing the delivery ofecosystem services through better catchment management should not only be theresponsibility of the public sector, but also the private and third sectors.

Alongside this movement towards shared responsibility, there is also now a growingbody of evidence that far greater environmental improvements can be achieved if all ofthe groups actively involved in regulation, land management, scienti c research orwildlife conservation in a catchment area are drawn together with landowners and otherinterest groups to form a catchment management partnership.

A number of research projects have now been able to demonstrate that an empoweredcatchment area partnership comprised of diverse stakeholders and technical specialistsfrom 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. Theyhave also shown us that an integrated stakeholder driven assessment of a catchmentwill we be enable us to develop a comprehensive understanding of the challenges weface and, following this, to develop a strategic, targeted, balanced and therefore coste ective catchment management intervention plan.

Overall (top) and sh (bottom) status ofwaterbodies in the Tamar catchmentunder theWater Framework Directiveclassi cation system.

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T ‘Ca n -Ba e Ap oa h’ (C A) In response to this increased understanding of the potential bene ts of participatorycatchment planning, undertaken with local stakeholders and knowledge providers, in2011 the Environment Minister Richard Benyon MP announced that the UK Governmentwas committed to adopting a more ‘catchment based approach’ to sharing information,working together and coordinating e orts to protect England’s water environment.

Following their announcement, DEFRA began working with the Environment Agency toexplore improved ways of engaging with people and organisations that could make areal di erence to the health of our rivers, lakes and streams.

In the summer of 2011, they launched a new initiative to test the catchment partnershipapproach in ten 'pilot' catchments. Alongside these ten Environment Agency led pilotsthey also established fteen further pilot catchments that would be hosted by otherorganisations.

The outputs of the DEFRA Catchment Pilot Projects, which are now presented on theCatchment Change Management Hub website (ccmhub.net), reveal that the newpartnerships created in many catchments were able to generate ambitious andcomprehensive plans for the improvement of river ecological health and water quality.

In response to the success of the Pilot Catchments, in May 2013 DEFRA announced theirpolicy framework for the roll out of the Catchment Based Approach (CaBA) to all of the~80 catchments in England and catchment hosts will be selected in autumn 2013.

Ru l Ec n & n (R L ) P o The interdisciplinary RELU Programme, funded between 2004 and 2011, had theaim of harnessing the sciences to help and promote sustainable rural developmentand advance understanding of the challenges caused by this change today and inthe future. Research was undertaken to inform policy and practice with choices onhow to manage the countryside and rural economies.

The ndings of several RELU projects highlighted the need for more sustained andtwo way communication with stakeholders about land management. Theresearchers have demonstrated that new ‘knowledge bases’ can be established thatcombine local knowledge with external expertise.

The research has also identi ed a number of techniques that enable stakeholders,who may start with di erent views and levels of understanding, to rede ne theissues collectively in a way that can help them nd innovative solutions withmultiple bene ts.

C SE S Y

Perhaps the best example of this work is the ESRC fundedRELU study, led by Laurie Smith from SOAS at theUniversity of London, which developed the concept of a‘catchment area partnership’ (CAP) and ‘catchment areadelivery organisations’ (CADO) approach for the deliveryof catchment management in England andWales.

Piloted in the Tamar and Thurne catchments, the projectdrew on the scienti c and social accomplishments ofseveral innovative catchment programmes in the USAand other European countries and examined how theycould be adapted for use in the UK.

The SOAS project established a clear catchment management ‘roadmap’ (above) on how to: create a catchmentpartnership, integrate scienti c investigation with policy, establish governance and legal provisions; foster decisionmaking and implementation at the appropriate governance level to resolve con icts; and to share best practice.

Several of the other RELU research projects to focus on catchment management characterised a positive feedback loopin participatory catchment management planning whereby small initial changes initially yield a small bene t that, inturn, goes on to encourage far bigger changes later in the process. The common result of this feedback loop is thebuilding of local capacity through levering in tangible new resources, including fresh commitments of time and externalfunding and the supply of expertise.

The DEFRA Catchment Based ApproachPolicy Framework, May 2013.

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Ca n -Ba e Ap oa h (C A) P l To develop an understanding of how the catchment based approach could work in practice, a series of catchment levelpartnerships were developed through a pilot phase (May 2011 to December 2012). Ten of these partnerships were hostedby the Environment Agency (EA) and 15 were led by a range of stakeholders such as Rivers Trusts, Groundwork, watercompanies and community groups. A group of 41 wider catchment initiatives were also established that were not part ofthe formal evaluation.

Some examples of successful catchment partnerships established through the pilot phase of the catchment basedapproach are summarised below.

C SE S Y

The Tamar PlanThe Tamar Catchment Plan adopted a stakeholder led ‘ecosystem services’ approachto catchment planning. This has involved the host organisation working withstakeholders to identify areas within the catchment which play, or have the potentialto play, a particularly important role in the delivery of clean water and a range ofother bene ts (services) to society.

Through this process the stakeholders have developed; (1) a shared understanding ofthe pressures a ecting ecosystem service provision in the catchment, (2) a sharedvision for a catchment landscape with a blend of environmental infrastructure thatmay be able to deliver all of these vital services optimally in the future, and (3) a clearunderstanding of what is currently being done to realise this vision and whatadditional actions may be required to bring it to full reality.

Saving EdenThe Eden Pilot Project, hosted by Eden Rivers Trust within the Eden and Eskmanagement catchment encouraged greater levels of participation includingincreased levels of engagement with ‘di cult to reach’ groups and facilitation ofknowledge exchange between stakeholders. The pilot project produced a plan called‘Saving Eden’, which summarises the current health and the necessary actionsrequired to deliver Good Ecological Status in the Eden catchment.

Saving Eden says, ’we asked over 1,000 people, face to face or online, whether andwhy they care about rivers and how a plan might work...People told us that they careabout things that aren’t really critical to WFD: beauty, wildlife, access and havingwater for them to use. Our catchment community wants a plan that is about thesethings as well. So our plan is going to be about what people care about, the necessaryWFD requirements, and achieving other parallel standards like those in the HabitatsDirective. Where there are di erent standards we will pursue the highest one possible.’

The Tyne Catchment PlanThe Tyne Catchment Plan was created by Tyne Rivers Trust who asked people in thecatchment to tell them about the biggest issues for their rivers and to suggestprojects to tackle those issues.

The Tyne Catchment Plan, which is the result of that process, is a ‘wish list’ ofproposed projects that will; (1) deliver better rivers for people to enjoy and value, (2)increase community involvement in local decision making about river issues, (3)engage and educate those who don’t know the value and importance of rivers, (4)create robust and resilient environments which will cope with weather extremes andclimate change, (5) make best use of the available resources, research and evidencein supporting work across the catchment, and (6) help deliver the targets set out inEuropean legislation like theWater Framework Directive and the Habitats Directive.

The planning process undertaken in the Tyne Catchment included a survey to whichover 200 people responded and which raised 342 di erent issues across thecatchment. The results of this survey gave them a real understanding of what peoplethink is important for the future of the Tyne and its tributaries.

The process also included a full assessment of all the projects already underway inthe catchment and developed a prioritised list of 58 new proposed projects that thecatchment partnership thought would be important going forward.

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F nf a i & c n acThe 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 waterimpoundments in the Westcountry and to advance the education of the public in themanagement of water.

Our vision is:

A healthier living, working natural environment on a landscape scale.

Protection of ecosystem function and natural resources, particularly water.

To facilitate a move towards a society that values the natural environment and theservices it provides – Payments for Ecosystem Services.

Educate and reconnect society with the natural environment.

To base our work on good scienti c research.

To nd out more out more about the Westcountry Rivers Trust please visit our websiteatwww.wrt.org.uk or contact one of our team;

Dr Dylan Bright Director

Trained as a limnologist and freshwater ecologist Dylan is Director of the Rivers Trustand Managing Director of Tamar Consulting. He is an experienced farm and landmanagement advisor and has led Defra funded projects investigating Water FrameworkDirective Metrics and implementation of catchment management plans to inform goodstatus.

Email: dylan@wrt.org.uk

Dr Laurence Couldrick Head of Catchment Management

Dr Laurence Couldrick is the Head of Catchment Management at the WestcountryRivers Trust and Project manager for the Interreg funded WATER Project on thePayments for Ecosystem Services approach to river restoration.

Email: laurence@wrt.org.uk

Dr Nick Paling GIS & Communications Manager

Nick is an applied ecologist and conservation biologist with 8 years of experience usingspatial techniques to inform conservation strategy development and catchmentmanagement. He provides data, mapping & modelling support for all Trust projects andcoordinates and manages a number of large scale monitoring programmes currentlybeing undertaken by the Trust.

Email: nick@wrt.org.uk

Lucy Morris Data to Information O cer

Lucy is an ecologist and data analyst specialising in the communication of the Trust’sscienti c outputs to a wide variety of audiences. Lucy collates and assesses data andevidence before preparing press releases, articles and technical documents forpublication in a variety of media types, including traditional print media, lm/TV, online/websites and newmedia such as social networking sites.

Email: lucy@wrt.org.uk

Hazel Kendall Upstream Thinking Project O cer

Working with Upstream Thinking partners to collate information and data collection forreporting, Hazel will combine this role with bio monitoring undertaken as part of theproof of concept study supporting the physical works of the initiative, using a range ofsampling techniques and Biotic Indices.

Email: hazel@wrt.org.uk

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The Upstream Thinking Project is South West Water's agship programme ofenvironmental improvements aimed at improving water quality in river catchments inorder to reduce water treatment costs. Run in collaboration with a group of regionalconservation charities, including the Westcountry Rivers Trust and the Wildlife Trusts ofDevon and Cornwall, it is one of the rst programmes in the UK to look at all the issueswhich can in uence water quality and quantity across entire catchments.

The principal, over arching aim of any catchment management work is to improve thewater quality in our freshwater ecosystems and to make a signi cant contribution to theirattainment of good ecological status in accordance with requirements of the EU WaterFramework Directive. It is therefore vital that su cient evidence is collected to provide anobjective and robust assessment of the improvements delivered.

In this review we explore the data and evidence available, which, taken together,demonstrate qualitatively and quantitatively that the delivery of integrated catchmentmanagement interventions can realise genuine improvements in water quality. Tosupport the evidence collected, we have also summarised a number of case studies whichdemonstrate catchment management in action.