Upstream Thinking Catchment Management Evidence Review - Water Quality

Catchment Management Evidence Review

WATER QUDŽLIǝ Y

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Bringing people together to understand how to achieve a better more sustainable environment COLLABOR8 is a transnational European project, funded by the Interreg IVB North West Europe programme, which aims to contribute to the economic prosperity, sustainability and cultural identity of North West Europe in increasingly competitive global markets. This is being 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 and overcoming 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 ƪagship programme of environmental improvements aimed at improving water quality in river catchments in order to reduce water treatment costs. Run in collaboration with a group of regional conservation charities, including the Westcountry Rivers Trust and the Wildlife Trusts of Devon and Cornwall, it is one of the Ƥrst programmes in the UK to look at all the issues which can inƪuence water quality and quantity across entire catchments.

Published by: Westcountry Rivers Trust Rain Charm House, Kyl Cober Parc Stoke Climsland Callington Cornwall PL17 8PH Tel: 01579 372140 Email: info@wrt.org.uk Web: www.wrt.org.uk © Westcountry Rivers Trust: 2013. All rights reserved. This document may be reproduced with prior permission of the Westcountry Rivers Trust.

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CONTNJNǝS Introduction

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o Fresh water: a vital ecosystem service o Pressures aơecting water quality

o Factors that determine pollution risk o The catchment management ‘toolbox’ o Assessing the eƥcacy of interventions

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Pollutant Summaries

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o Nutrients & algae

o Suspended solids & turbidity o Pesticides

o Microbes & parasites

o Colour, taste & odour

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Assessing improvements

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Governance & planning

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INTƺOD8CƼƮON

Fresh watʑɠ: Ɉ viWɪl ecoʣyVtʑm ȿʑʢviȪɏ Rain falling on the land brings life to the plants and animals living upon it, but it also collects and runs across the land forming rills, gullies, streams and ultimately rivers. The transfer of fresh water onto and then across the land is one of the fundamental processes that sustain life on Earth. All of us depend on the fresh, clean water in our rivers and streams every day – we drink it, we bathe in it and it sustains other life on which we depend for food and enjoyment.

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

While the former EC Directive refers to the quality of raw water intended for human consumption, the latter sets targets above which it is expected that the ecological condition 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 to avoid any deterioration in water quality, such that the level of puriƤcation treatment required in the production of drinking water is reduced.

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

Furthermore, there are certain pollutants or physical characteristics that, when they occur in the raw water, can severely aơect the eƥciency of the drinking water treatment process. When these pressures do occur, or when the water treatment process does not take account of a speciƤc pollutant or group of pollutants, there can be an increased risk that the treated drinking water may fail to reach the drinking water standards required at the point of consumption (the tap).

PreVʣureɡ ɈՔecʤʖng watʑɠ qXɪʙiʤɨ Aquatic ecosystems can be damaged or degraded by a wide variety of pressures, which arise either from human activities being undertaken in speciƤc locations (point sources) or from the cumulative eơects of many small, highly dispersed and often individually insigniƤcant pollution incidents (diơuse sources).

Highly localised, point sources of pollution occur when human activities result in pollutants being discharged directly into the aquatic environment. Examples include the release of industrial byǦproducts, eƫuent produced through the disposal of sewage, the overƪows from drainage infrastructure or accidental spillage.

Superimposed on the pressures exerted by point sources of pollution are the more widely dispersed and less easily characterised diơuse pollution sources.

When large amounts of manure, slurry, chemical phosphorusǦcontaining fertilisers or agrochemicals are applied to land, and this coincides with signiƤcant rainfall, it can lead to runǦoơ or leaching from the soil and the subsequent transfer of contaminants into a watercourse. In addition, cultivation of arable land in particular ways or the over disturbance of soil by livestock (poaching) can make Ƥne sediment available for mobilisation and subsequent transfer to drains and watercourses by water running over the surface.

Other diơuse sources include the runǦoơ of pollutants from farm infrastructure such as dung heaps, slurry pits, silage clamps, feed storage areas, uncovered yards and chemical preparation/storage areas.

Animal access to watercourses can also lead to the direct delivery of bacterial and organic compounds to the water and to their reǦmobilisation following channel substrate disturbance. It should be noted that, while these agricultural sources of pollution can often appear more like point sources, they are, however, considered as diơuse sources as they relate to widespread, landǦbased, rural practices that that can have signiƤcant cumulative eơects.

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

Nutrients. Phosphorus & nitrogenǦcontaining 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

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

Some soils, such as heavy clayǦ or peatǦbased ‘stagnogleys’, are more susceptible to damage, such as compaction, caused by intensive cultivation or livestock farming. This increases the risk of erosion or signiƤcant surface runǦoơ occurring from their surface.

Other soil types, such as lighter, freeǦdraining ‘brown earth’ soils, can have pollutants leached away by water passing rapidly down through them. In addition, soils with very high levels of organic matter, such as peat, can release large quantities of organic compounds 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 a powerful method for minimising the risk of pollution occurring as a result of their innate structural vulnerability.

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

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

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The risk that an area of land poses to the provision of an ecosystem service, such as the regulation of water quality, can be conceptualised as the interaction between the inherent characteristics of the land and the activities or practices being undertaken upon it. Therefore, it is possible to identify areas where potentially risky practices are being undertaken and where this coincides with a high underlying risk that water quality could be degraded. These highǦscoring areas can be considered the priority for the targeting of catchment management interventions and also where the greatest enhancement of ecosystem service provision may be achieved.

PRACTICE

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

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INHERENT RISK

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

Given the fact that certain areas, due to their morphology, have an elevated level of hydrological connectivity and an increased probability that water will ƪow laterally across their surface, it is vital that we identify them and design tailored management interventions to mitigate any risk that they may generate pollution.

Hydrological assessment of a river valley

LandǦuse & landǦcover The use to which a parcel of land is put can have a signiƤcant eơect on its ability to regulate the movement of water across it and the likelihood that it will generate pollution in the aquatic environments nearby.

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

In contrast to natural habitats, land in agricultural production experiences greater levels of disturbance, whether through cultivation or the actions of livestock, and there is therefore greater risk that it will become damaged and become susceptible to erosion, pollutant washǦoơ or pollutant leaching.

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

Land under permanent grassland (pasture) inherently represents a lower pollution risk due to its undisturbed soil and more mature vegetation. However, even this landuse can generate signiƤcant levels of pollution when its soil surface becomes damaged by high livestock density or when large levels of nutrients or pesticides are applied to improve it.

When assessing the risk that diơuse pollution may occur, there are also areas of urban and industrial landuse that should not be overlooked. SigniƤcant levels of pollutants (such as sediment, oil, metals, pesticides and a variety of other chemicals) can be mobilised from the often impermeable surfaces and drainage systems connected to watercourses in urban environments.

In light of these diơerences in the ability of diơerent landǦuses and landǦcovers to generate pollution, it is clear that either changing landǦuse or ensuring that best management practices are undertaken on each particular landǦuse represent the most important methods for the mitigation of landǦuse driven pollution risk.

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Practice & land management While soil characteristics, morphology, hydrology and landǦcover all contribute the innate potential for land to generate water pollution, it is ultimately the management of land and the practices that are undertaken upon it that will determine the likelihood and scale of any pollution that occurs.

The intensity and timing of our activities can aơect the ability of land to retain pollutants and so increase the likelihood of pollution arising from it. The risk of pollution occurring can be increased when land is overǦstocked with livestock in vulnerable locations or at times of elevated risk due to the increased chance of heavy rainfall. The risk can also be increased when land is drained, compacted with machinery or when it becomes damaged by repeated cycles of intensive cultivation and crop production.

Paul Anderson

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

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

CDŽSE SƼǟLjY Mʋpʠʖng ȴʑɨ ʋreaɡ fʝɠ ʃȱɏ ʠUʝviʣiʝɚ Է ʓresh watʑɠ aɡ ʋɚ ecoʣyVtʑm ȿʑʢviȪɏ There are areas of land where, due to the physical characteristics of the location or a sudden change in the weather, any land management practice, irrespective of whether it is inherently risky and despite best practice being observed, can still result in the generation of pollution. On this high priority land, there is the greatest likelihood of water quality being degraded and for the ecosystem services dependent on it to be compromised. In addition, these are also the areas where the greatest environmental beneƤts may be realised for the minimum investment.

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

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A CaWɭʕȷʑnɢ MʋnaȰʑȷʑnɢ Toɼɸbʝx If we can determine which pressures are exerting negative impacts on the water quality in our aquatic ecosystems and identify their sources in a catchment, then we can develop a programme of tailored and targeted interventions to remove these sources and disconnect their pollution pathways.

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

In contrast to point sources of pollution, the various sources of diơuse pollution in catchments are far harder to identify and, individually, their impacts are often too slight, intermittent or transient to quantify with great accuracy and certainty. Despite these challenges, however, there is now a wealth of evidence and data which do allow these diơuse sources of pollution to be identiƤed and for programmes of interventions and measures to be developed to mitigate their impacts.

Over the last 10Ǧ15 years a comprehensive suite of land management advice and onǦ farm measures has been developed to minimise loss of pollutants from farms while maximising eƥciency to increase yields and save costs. Some of the most common of these soǦcalled Best Farming Practices (BFPs) that are now recommended to farmers, and which are now being delivered on farms across the UK, are illustrated on the following page.

There are now many organisations that have skilled, knowledgeable and highly qualiƤed farm advisors who are able to give advice on farming practices, including; Catchment Sensitive Farming, Rivers Trusts, Wildlife Trusts, SoilsǦforǦProƤt, Natural England, the Environment Agency and the Farming & Wildlife Advisory Group to name just a few. In addition, land managers also obtain a considerable amount of advice from their own agronomists and farming advisors.

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

During the development of the onǦfarm intervention toolbox there were a number of key design considerations taken into account, which allow a farm advisor to correctly tailor and target their application:Ǧ

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

Applicability. Each measure must have the farming systems, regions, soils and crops to which it can be applied clearly deƤned. Farm advisors must recommend interventions that are suitable for the situation found on a particular farm.

Feasibility. The ease with which the measure can be implemented and any potential physical or social barriers to its uptake or eơectiveness must be identiƤed. Careful consideration must be given to measures that may impact other farming practices.

Costs & beneƤts. The cost of implementing, operating and maintaining the measure must be clearly understood. The potential practical and Ƥnancial beneƤts to the farmer of implementing the measure must also be estimated as it is vital for encouraging uptake of the measures. In some circumstances, where the cost is high or the measure will result in a loss of income, the farmer or farm advisor may need to Ƥnd additional funding from incentive or capital grant schemes to enable delivery.

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

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In this review, for each of the Ƥve main pollutant categories, we give an overview of the interventions that can been delivered to mitigate the impacts of pollution on; (1) the ecological health of our river catchments, (2) the risks and costs incurred at drinking water treatment works through having to treat low quality raw water, and (3) on the generation of pollutionǦderived problems in the estuaries and coastal regions in the lower reaches of river catchments.

Furthermore, we also describe the catchment management interventions considered to be the most eơective in reducing diơuse pollution and mitigating the impacts described.

We will also attempt to evaluate and summarise the numerous studies (completed or currently underway) which allow us to estimate the scale of beneƤt that these catchment management interventions can deliver at a variety of scales.

In assessing and collating this evidence, we hope that we will be able to demonstrate with some certainty that signiƤcant improvements in water quality can be achieved through the targeted and integrated implementation of catchment management interventions.

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

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

In addition to broad advice on good or best practice, an integrated farm advice package should produce a targeted and tailored programme of measures that could be undertaken and should include speciƤc advice on pesticide, nutrient and soil management 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 loss of pollutants to watercourses as a result of agricultural activity.

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

Incentivisation to change farming practice At present, farmers, who represent less than 1% of our society, currently manage nearly 80% of our countryside and are largely responsible for the health of the ecosystems it supports. However, despite their key role in managing our natural ecosystems, farmers are currently only paid for the provision of one ecosystem service; food production.

Devon Wildlife Trust

To redress this apparent imbalance, there are now a number of funding programmes through which land managers and farmers can receive payments for adopting more environmentally beneƤcial and ecosystem servicesǦenhancing practices on all or part of their land. Schemes of this type, in which the beneƤciaries of ecosystem services provide payment to the stewards of those services, are often referred to as Payments for Ecosystem Services (described in more detail in Assessing Improvements on p64).

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

Farming community engagement & education Educational and training activities, such as farmer meetings and workshops, which raise awareness of diơerent initiatives and promote best practice among local farming communities, are a key component of any catchment management programme. They also serve to establish relationships and build trust between advisors and farmers on the ground in a catchment.

CDŽSE SƼǟLjY /ƩAF (/ʖɻʘʖng EʜvʖUʝʜȷʑnɢ Anɍ Fʋʢʛʖng) LEAF is the leading organisation promoting sustainable food and farming. They help farmers produce good food, with care and to high environmental standards, identiƤed inǦstore by the LEAF Marque logo. LEAF attempts to build public understanding of food and farming in a number of ways, including; Open Farm Sunday, Let Nature Feed Your Senses and year round farm visits to our national network of Demonstration Farms.

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

LEAF also provide a wide array of educational and best practice guidance resources on their website, including their Water Management Tool, which oơers farmers a complete health check for water use on their farms, and the Simply Sustainable Water Guidance booklet and Ƥlm. The Simply Sustainable Water booklet has been produced to help farmers develop an eơective onǦfarm management strategy for eƥcient water use and to improve their farm’s contribution to protecting water in the environment. It allows farmers to get the best from this valuable resource, to improve awareness of the importance of water and track changes in water use and quality over time.

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

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'ɰʙʖɃʑʢɨ ȷeʃKoGɡ fʝɠ caWɭʕȷʑnɢ PʋnaȰʑȷʑnɢ At present there are a number of diơerent programmes and initiatives via which catchment management interventions are funded to deliver catchmentǦscale improvements in water quality through the delivery of land management advice and onǦ farm measures.

Perhaps the most signiƤcant of these are; the Natural EnglandǦcoordinated Catchment Sensitive Farming initiative, some elements of the Natural England Environmental Stewardship Scheme and a number of newly established water companyǦfunded schemes, such as the South West Water Upstream Thinking Initiative and the United Utilities Sustainable Catchment Management Programme (SCaMP).

In addition to these programmes, the Environment Agency, Natural England, the Forestry Commission and a number of nonǦgovernmental organisations also make considerable investment of their resources in the delivery of advice and practical support for people managing natural resources in the catchment.

Each of these catchment management programmes have diơerent funding mechanisms and use diơerent methods to target and deliver funding. For example, Catchment Sensitive Farming oơers smallǦmedium grants (up to £10,000 per farm) for capital investments in farm infrastructure in its priority catchments alongside a programme of advice and training. In contrast, Environmental Stewardship Schemes oơer revenue payments in return for the delivery of a suite of onǦfarm measures in their target areas.

CDŽSE SƼǟLjY CaWɭʕȷʑnɢ SʑnʣiʤʖɃɏ Fʋʢʛʖng Funded by DEFRA and the Rural Development Programme for England, Catchment Sensitive Farming (CSF) is a joint initiative between the Environment Agency and Natural England that has been established in a number of priority catchments across England.

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 deliver environmental beneƤts such as reducing water pollution, cleaner drinking water, safer bathing water, healthier Ƥsheries, thriving wildlife and lower ƪood risk for the whole community.

To achieve these goals CSF delivers practical solutions and targeted support which should enable farmers and land managers to take voluntary action to reduce diơuse water pollution from agriculture to protect water bodies and the environment.

Catchment Sensitive Farming Oƥcers work with independent specialists from the farming community to deliver free advice tailored to the area and farming sector. This advice includes workshops, farm events and individual farm appraisals. CSF also oơer capital grants, at up to 60% of the total funding, to deliver improvements in farm infrastructure.

As part of the Catchment Sensitive Farming programme, Natural England have also undertaken an evaluation study to demonstrate the beneƤts that the delivery of advice and measures have realised.

In addition to a summary report (http://tinyurl.com/mzyrpc7), Natural England have also produced a number of case studies and technical reports covering speciƤc areas; such as, advice and education delivery, water quality monitoring and environmental modelling. These can be accessed at http://tinyurl.com/pk5rulg.

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Like Catchment Sensitive Farming, the South West Water Upstream Thinking initiative also oơers capital grants for onǦfarm infrastructure improvements, but it also places conditions on the management of the new infrastructure and on other activities undertaken on the farm following the investment via a deed of covenant.

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

CDŽSE SƼǟLjY 8pVʤreʋm Tʕʖɻʘʖng South West Water (SWW) in collaboration with a group of regional conservation charities, including the Westcountry Rivers Trust, the county Wildlife Trusts for Devon and Cornwall and The Farming and Wildlife Advisory Group, have established one of the largest and most innovative conservation projects in the UK: the ‘Upstream Thinking Initiative’.

This project will deliver over £9 million worth of strategic land restoration in the Westcountry between 2010 and 2015.

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

Fowey River Improvement Auction In the Ƥrst scheme of this kind in the UK, an auction was successfully used to distribute funds from a water company to farmers, investing in capital items to improve water quality. The work was supported by the Natural Environment Research Council Business Internship scheme, managed by the Environmental Sustainability Knowledge Transfer Network.

The scheme oơered SWW the opportunity to work directly with researchers from the University of East Anglia to devise an innovative mechanism for paying for the delivery of ecosystem services via their Upstream Thinking scheme.

Upstream Thinking uses an advisorǦled approach in other areas.

Advisors from the Westcountry Rivers Trust visit farms to suggest work and pay grants at a Ƥxed rate. The disadvantages of this approach are that it’s labour intensive, not practical to visit all farms and the potential for all the funds to be used on a small number of farms. The main advantage is that advisors can suggest investments most likely to improve water quality.

The University of East Anglia devised an auction approach, working with Westcountry Rivers Trust to: (1) increase coverage by encouraging all eligible farmers to participate, and (2) achieve maximum water quality beneƤts at the same time as achieving eƥciency for SWW’s investment.

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

Farmers were asked to enter sealed bids up to a maximum 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 rates paid in the scheme from 38% to the full 100%.

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AVȿeVʣʖng ʃȱɏ eɑ£caʎɨ Է ʖntʑʢɃʑnʤiʝnɡ The principal, overǦarching aim of catchment management is to improve raw water quality in lakes, rivers and coastal waters. If eơective, this approach could make a signiƤcant contribution to their attainment of good ecological status, in accordance with the EU Water Framework Directive.

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

Given the potentially signiƤcant role of this approach in the improvement of water quality, it is vital for that we collect suƥcient evidence to provide an objective and scientiƤcally robust assessment of the eơectiveness of the interventions used.

Ultimately, we must be able to justify that the money spent and the interventions delivered across the landscape have delivered both signiƤcant improvements in water quality and a number of secondary Ƥnancial, ecological and social beneƤts.

Determine water quality impacts

Identify & qualify pressures

Locate sources & pathways

Develop programme of measures

Fund & deliver measures

Measure improvements

R In this review we have attempted to collect a comprehensive and robust set of data and evidence, which, taken together, demonstrates qualitatively and quantitatively that the delivery of integrated catchment management interventions can deliver genuine improvements in water quality.

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

Record secondary beneƤts

A summary of the cyclical and adaptive catchment management process: from the characterisation of impacts to the identiƤcation of pressures and on to the delivery of measures and the evaluation of improvements achieved.

We have also identiƤed key mitigation measures for reducing pollutant loads and evaluated the data and evidence for the eƥcacy of these measures. This process has also allowed us to identify the interventions for which the evidence of eƥcacy does not exist or where it does not exist at an appropriate scale.

Section 7 addresses issues of scale and reviews a selection of modelling tools that can be used to predict the impact of interventions and measures at a larger subǦ catchment or wholeǦcatchment scale. This section also explores the potential for secondary environmental, economic and societal beneƤts to result from the delivery of catchment management interventions.

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

Assessing Ƥsh populations using electroƤshing

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NUTRIENTS & ALGAE

ƴ8TƺINJNǝS & DŽǒGAE

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NUTRIENTS & ALGAE

N8TƺINJNǝS & AǒGAE NitrogenǦ and phosphorusǦcontaining compounds (often termed nutrients) are natural and vital components of healthy aquatic ecosystems. They play a critical role in supporting the growth of aquatic plants, which, in turn, produce oxygen and provide habitats that support the growth and reproduction of other aquatic organisms.

NitrogenǦ and phosphorusǦcontaining nutrients also support the growth of algae, another natural component of many aquatic ecosystems. Algae occur in the benthic and planktonic phases of freshwater habitats and form a key component of the food chain for many species of Ƥsh, shellƤsh and invertebrate assemblages.

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

When nutrients accumulate in aquatic ecosystems they drive the uncontrolled and unbalanced growth of aquatic plants and algae in a process called eutrophication and these soǦcalled plant or algal ‘blooms’ can then cause severe problems for other aquatic organisms, the ecological health of a waterbody and for the humans who also depend on the water for drinking water, recreational use or for the production of food such as Ƥsh and shellƤsh.

SʝuUȪeɡ Է ʜXʤʢȲʑnWɡ There are three principal sources of nitrogenǦ and phosphorusǦcontaining compounds in a river catchment: point anthropogenic sources, point agricultural sources and diơuse agricultural sources.

Point anthropogenic sources. A considerable fraction of the phosphorus in river water may be derived from inputs of sewage eƫuent (which may or may not have been treated), from drainage systems in urban areas, septic tanks and from roadside drains. The principal sources of phosphates and nitrates in sewage are human faeces, urine, food waste, detergents and industrial eƫuent that have been discharged to the sewers. Typical sewage treatment processes generally remove 15Ǧ40% of the phosphorus compounds present in raw sewage and there are many small sewage treatment facilities and septic tanks in rural areas which could also be making signiƤcant contributions to the phosphorus load in rivers and reservoirs.

Point agricultural sources. These include farm infrastructure designed to store and

There are numerous potential sources of nutrients in river catchments; including sewage discharges (top), agricultural point sources such as slurry stores (middle) and diơuse sources such as fertiliser applied to agricultural land (bottom).

manage animal waste and other materials such as animal food. Key infrastructure includes dung heaps, slurry pits, silage clamps and uncovered yards. Animal access points to watercourses can also lead to the direct delivery of phosphorus compounds to the water and to their mobilisation following channel substrate disturbance.

Diơuse agricultural sources. When large amounts of manure, slurry or chemical phosphorusǦcontaining fertiliser are applied to land, and this coincides with signiƤcant rainfall, it can lead to runǦoơ and the transfer of phosphorus into watercourses. This is a particular problem where heavy soils are farmed intensively, which can result in their compaction and an increased risk of surface runǦoơ.

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

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

However, water quality sampling can be costly and time consuming, when undertaken at Ƥne temporal or spatial scales, and much of the work to identify sources of nutrient pollution in river catchments has therefore focused on the use of models such as the Extended Nutrient Export Coeƥcient Plus (University of East Anglia), the Phosphorus and Sediment Yield CHaracterisation In Catchments (PSYCHIC) model (ADAS Water Quality) and the new Source Apportionment GIS (SAGIS) tool (Atkins UK).

17

Robert Marshall

NUTRIENTS & ALGAE

CDŽSE SƼǟLjY SʝuUȪɏ Aʠpɛԯiʝʜȷʑnɢ-GǏS (ƻDŽGǏS) Podɰɸʙʖng ʓUʋȷʑwʝʁk The Source ApportionmentǦGIS (SAGIS) modelling framework was developed through UWKIR research project WW02: Chemical Source Apportionment under the WFD (UKWIR, 2012) with support from the Environment Agency. The primary objective of this research was to develop a common modelling framework as the basis for deriving robust estimates of pollution source contributions that would be used to support both water company business plans and the EA River Basin Planning process.

The SAGIS tool quantiƤes the loads of pollutants to surface waters in the UK from 12 point and diơuse sources including wastewater treatment works discharges, intermittent discharges from sewerage and runoơ, agriculture, soil erosion, mine water drainage, septic tanks and industrial inputs (UKWIR project WW02). Loads are converted to concentrations using the SIMulation of CATchments (SIMCAT) water quality model, which is incorporated within SAGIS, so that the contribution to inǦstream concentrations from individual sources can be quantiƤed.

Diơuse sources of nutrient pollution are incorporated into SAGIS from the Phosphorus and Sediment Yield CHaracterisation In Catchments (PSYCHIC) model (developed by a consortium of academic and government organisations led by ADAS Water Quality).

PSYCHIC is a processǦbased model of phosphorus and suspended sediment mobilisation in land runoơ and subsequent delivery to watercourses. Modelled transfer pathways include release of desorbable soil phosphorus, detachment of suspended solids and associated particulate phosphorus, incidental losses from manure and fertiliser applications, losses from hard standings, the transport of all the above to watercourses in underǦdrainage (where present) and via surface pathways, and losses of dissolved phosphorus from point sources.

The maps below show the baseline export of total phosphorus from manureǦbased sources across the Tamar catchment predicted by the PYCHIC model (inset) and the modelled concentrations of Soluble Reactive Phosphate in subǦ catchments of the Tamar and their sources according to the SAGIS modelling tool (main).

18

NUTRIENTS & ALGAE

IʛpacWɡ Է ʜXʤʢȲʑnWɡ On the health of aquatic ecosystems The principal eơect of accelerated plant growth and algal blooms is the reduction (hypoxia) or elimination (anoxia) of oxygen in the water as oxygenǦconsuming bacteria decompose the plants and algae when they die back. This reduction in the oxygenation of a waterbody can have a severe eơect on the normal functioning of the ecosystem, causing a variety of problems such as a lack of oxygen needed for Ƥsh, shellƤsh and invertebrates to survive.

Under the Water Framework Directive (WFD) classiƤcation scheme the ecological impacts of nutrients on freshwater systems are recorded through the changes that they exert on the plant and algal communities that are found in them. Changes in the composition of these communities are interpreted as an indication that nutrient enrichment 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 relatively poorly understood but, as with freshwaters, excessive nutrient loads can cause their eutrophication. The susceptibility of estuaries to nutrient enrichment depends on factors such as the physical characteristics, the hydroǦdynamic regime and the biological processes that are unique to each individual estuary. Generally speaking, estuaries and coastal areas are thought to be less susceptible to eutrophication due to their tidal nature, which results in high turbidity (less light penetration) and frequent ƪushing.

Estuaries with good light regimes are often more sensitive to nutrient enrichment.

Water starworts (Callitriche spp) (top) are just one group of macrophyte plants that can cause problems when they proliferate excessively. PhytoǦ benthic algae (diatoms) are particularly sensitive to nutrient enrichment (bottom).

Primary producers in estuaries may be opportunistic green algae, epiphytes or phytoplankton and excessive growth of any or all of these can impact on water turbidity and light availability, causing changes in the depth distributions of plant communities in the water column. Such changes can have implications for the structure and functioning of estuarine and coastal food webs, with potential consequences for Ƥsh and shellƤsh Ƥsheries and for bathing water quality on neighbouring beaches.

In addition to the assessment of these biological indicators, the levels of Soluble Reactive Phosphorus (SRP) in waterbodies are also measured and, through comparison with established thresholds known to cause ecological impacts, the levels are used to identify where degradation might be expected to occur. The WFD threshold above which SRP is expected to have a signiƤcant impact on the ecological condition of an aquatic ecosystem varies between diơerent waterbody types, but an average SRP concentration above 50 ug/l would result in a WFD failure in any waterbody type.

Bob Blaylock

The Exe Estuary at Topsham

19

NUTRIENTS & ALGAE

On the provision of drinking water In addition to the ecological impacts of nutrient enrichment leading to hypoxia and/or anoxia in aquatic ecosystems, algal blooms can also result in other negative eơects that have signiƤcant consequences for the treatment and supply of drinking water.

These include their potential to damage property or water supply infrastructure, to increase algaeǦderived toxins in the water and to cause taste and odour problems, all of which can result in increased drinking water treatment costs.

These impacts are particularly felt as blooms of algae and explosions of macrophyte growth begin to dieǦback at the end of the summer growing season or following the depletion of nutrients and oxygen in the water column, when a number of soǦcalled decomposition biǦproducts can be released.

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

Ammonia and its ionised cationic form ammonium (NH4+) are naturally occurring components of the nitrogen cycle that are generated in aquatic ecosystems by heterotrophic bacteria as the primary nitrogenous endǦproduct of organic material decomposition. In healthy aquatic ecosystems ammoniacal nitrogen is readily assimilated by plants or converted through nitriƤcation to nitrate, but in eutrophic lakes, where elevated levels of nutrients are driving algal blooms and the development of stratiƤed hypoxic conditions, this process can be inhibited and ammoniacal nitrogen then accumulates rapidly.

The presence of ammoniacal nitrogen in water can begin to have a toxic eơect on aquatic organisms (especially Ƥsh) at concentrations above 0.2 mg/l. In addition, when abstracted for drinking water treatment, ammoniacal nitrogen concentrations above 0.2 mg/l can also cause taste and odour problems as well as decreased disinfection eƥciency during chlorination.

Summary of the annual costs associated with freshwater eutrophication in the UK. Costs were calculated as ’damage costs’ – i.e. the reduced value of clean or nonǦnutrientǦenriched water (adapted from Pretty et al., 2002).

The increased chlorination required to remove ammoniacal nitrogen during the treatment process can also lead to the indirect generation of dangerous chemical biǦ products such as trihalomethanes (THMs), which are thought to have toxic and/or carcinogenic properties and are very diƥcult to remove from the Ƥnal treated drinking water. Furthermore, increases in the nitriƤcation of ammonia in the raw water, and the increased consumption of oxygen that this entails, may also interfere with the removal of manganese by oxidation on the Ƥlters, which can result in the production of mouldy, earthyǦtasting water.

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

Cost categories

Range of annual costs (£ million)

Social damage costs

Reduced value of waterside dwellings

Health costs to humans, livestock and pets

£9.83 £0.50 Ǧ 1.00 £19.00 £20.10 £0.50 Ǧ 1.00 £5.12 Ǧ 7.99 £9.65 Ǧ 33.54 £2.94 Ǧ 11.66 £0.029 Ǧ 0.118 unknown

Reduced value of waterbodies for commercial use (abstraction, navigation, livestock, irrigation and industry) Drinking water treatment costs (treatment and action to remove algal toxins and algal decomposition products) Drinking water treatment costs (to remove nitrogen) CleanǦup costs of waterways (dredging, weedǦcutting) Reduced value of nonǦpolluted atmosphere (via greenhouse and acidifying gas emissions) Reduced recreational and amenity value of water bodies for water sports, angling, and general amenity Revenue losses for formal tourist industry Revenue losses for commercial aquaculture, Ƥsheries, and shellƤsheries

Ecological damage costs

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

£7.34 Ǧ 10.12

TOTAL

£75.0 Ǧ 114.3

20

There are a wide range of mitigation measures available for reducing nutrient inputs into the aquatic environment.

Soil, land and slurry management Limiting fertiliser and manure inputs to suit crop requirements prevents overǦuse and reduces the quantities of surplus nutrients entering the system. Mitigation measures to limit nitrogen inputs to suit crop requirements have been shown to substantially reduce nitrate losses from soil (Lord and Mitchell, 1998), but these methods are less eơective in reducing phosphorous concentrations in runǦoơ due to phosphorous buildǦup in soil.

The Westcountry Rivers Trust have produced a series of farmǦmeasure factǦ sheets, which can be found on the DEFRA website at—http://tinyurl.com/ kqpyctv.

Mitigation measures to reduce nutrient loads through changes in agricultural land and soil management practices include the use of fertiliser placement technologies and avoiding application of fertiliser to highǦrisk areas. There are also a variety of conservation tillage techniques that can be implemented, with the aim of reducing nutrient losses via surface runǦoơ.

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

Implementation of conservation tillage techniques Fertiliser spreader calibration Use of a fertiliser recommendation system Use of fertiliser placement technologies ReǦsite gateways away from highǦrisk areas Do not apply fertiliser to highǦrisk areas Avoid spreading fertiliser to Ƥelds at high risk times Do not apply P fertiliser to high P index soils Install covers on slurry stores Increase the capacity of farm manure storage Minimise volume of dirty water and slurry produced Change from slurry to solid manure handling system

The table below summarises key Ƥndings of research into the eƥcacy of mitigation measures aimed at limiting nutrient losses by changing agricultural land and soil management practices.

These Ƥndings are a result of research carried out at either a plotǦ or ƤeldǦ scale.

Reference

Mitigation Measure

Findings

Benham et al. (2007)

Implementation of conservation tillage techniques

Mean losses in surface runǦoơ for

Daverede et al. (2004)

Injection of slurry

93% reduction in dissolved reactive P in runǦoơ 82% reduction in total P in runǦoơ 94% reduction in algalǦavailable P in runǦoơ

Deasy et al. (2010)

Tramline management

Tramline management reduced nutrient and sediment losses by 72Ǧ99% on 4 out 5 sites and were a major pathway for nutrient transfer from arable hillǦslopes

Goss et al. (1988)

Direct drilling

Winter losses of nitrogen was on average 24% less than for land that had been ploughed

Johnson and Smith (1996)

Shallow cultivation (instead of ploughing)

Decreased nitrogen leaching by 44 kg per hectare over a 5 year period

Pote et al. (2003)

Incorporation of poultry litter in soil

80Ǧ90% reduction in nutrient losses from soil

Pote et al. (2006)

Incorporation of inorganic fertilisers into soil

Reduction of nutrient losses to the water environment to background levels

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

Planting a green cover crop

50% reduction in nitrate losses compared to winterǦ sown cereal. Uptake of nitrogen ranging between 10 and 150 kg per hectare

Withers et al. (2006)

Ensure tramlines follow contours of the land across the slope

No signiƤcant diơerences in runǦoơ quantity, sediment and total phosphorous loads compared to areas with no tramlines

Zeimen et al. (2006)

Ensuring a rough soil surface by ploughing or discing

Transport of soluble phosphorus in surface runǦoơ reduced by a factor of 2Ǧ3 compared to untilled soils

21

total nitrogen was reduced by 63% ammonia was reduced by 46% nitrate was reduced by 49% total phosphorus was reduced by 73%

NUTRIENTS & ALGAE

MiʤiJaʤiʝɚ ȷeaʣureɡ & ʃȱʑʖɠ eɑ£caʎɨ

NUTRIENTS & ALGAE

CDŽSE SƼǟLjY RʖɃʑɠ 2Խʑɠ CaWɭʕȷʑnɢ MʋnaȰʑȷʑnɢ PUʝjecɢ The River Otter rises in the Blackdown Hills in East Devon and runs for approximately 25 miles southwest to the sea.

Below Honiton, the Otter enters its ƪoodplain and runs south through several towns and villages before reaching the salt marshes at Budleigh Salterton. In its lower reaches, the Otter becomes a gravelǦbed river that meanders through rolling topography with mixed agricultural land use, including livestock, cereals, oil seeds, fruit and vegetables.

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

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

Delivery of Interventions Farm visits were made to engage with farmers and explain the beneƤts of better nutrient management. Where appropriate, farmers were provided with farm reports to highlight priority areas likely to inƪuence raw water quality and to provide advice on management practices to reduce pollutant loads. From 2010Ǧ2012, thirtyǦseven farms were visited and eight received farm reports. Events were also held to engage with the farming community whilst at the same time to bolster the understanding of the project aims. Events have included fertiliser spreader workshops, crop trial workshops and visits to the SWW water treatment works.

Following the visit to the water treatment works one farmer commented that the project was, “...very interesting. Our strategy has more inƪuence on water quality than I thought...”.

Monitoring & Outcomes Focusing on the nitrate contribution from agriculture, a monitoring study was set up to assess the relative contributions from diơerent 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 Ƥeld on each of their farms for testing, preǦ and postǦwinter. Each farm was 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 November 2011, March and November 2012 and March 2013. The diơerence in nitrate levels recorded in the soil between November and March gives a value for nitrogen lost over winter.

The chart (left) shows that overall levels of nitrogen lost from the soil has decreased signiƤcantly over the monitoring period, with levels in 2012/2013 approximately a third of the level lost over the 2010/2011 winter.

The amount of nitrogen used by the current crop has been taken into account, where appropriate, and the remaining fraction of nitrogen unaccounted for is considered to be associated with the export of animal products, crops, leaching, deǦnitriƤcation and volatilisation. In most cases, the nitrogen loss will mainly be associated with leaching, volatilisation and deǦnitriƤcation, all of which are environmentally damaging.

While these results are encouraging, there are several other factors that could have contributed to this reduction, such as the weather, and it is not possible to prove that these positive results are directly linked to interventions. However, they do oơer a snapshot of the problems faced in this area and certainly point towards a positive impact resulting from the provision 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 the project aims, as demonstrated by positive farmer feedback.

22

Sources of phosphorus in the EU

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

Reduction in stocking density Reduction in dietary N and P intakes Exclusion of livestock from waterbodies and provision of alternative drinking sources

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

Mitigation Measure

Findings

Heathwaite and Johnes (1996)

Reduced livestock grazing density

Phosphorous exports in surface runǦoơ was recorded as:

Huging et al. (1995)

Reduce livestock grazing density

x 2 mg total P per m2 for ungrazed land x 7.5 mg total P per m2 for lightly grazed land x 291 mg total P per m2 for heavily grazed land There is a signiƤcant relationship between grazing intensity and nitrogen losses to water Nitrogen leaching losses were reduced by 69%

Kurz et al. (2006)

Exclusion of livestock from poorly drained areas of land to prevent poaching

Line (2003)

Fencing the watercourse to exclude liveǦ stock combined with a 10Ǧ15m buơerǦstrip

Total phosphorous load decreased by 76%

Fencing the watercourse to exclude liveǦ stock

Streams within fenced oơ areas showed rapid improvement in visual water clarity and channel stability

Parkyn et al.(2003)

Decreased concentrations of total nitrogen, organic phosǦ phorous and potassium were measured in surface runǦoơ from unǦgrazed areas when compared to grazed areas Total organic nitrogen load decreased by 33%

Soluble reactive phosphorous decreased by up to 33% in some streams, although in others it increased Total nitrogen decreased by up to 40% in some streams but increased in others Sheƥeld et al. (1997)

Provision of alternative drinking source for livestock

Total phosphorus load decreased by 54% Total nitrogen load decreased by 81%

CDŽSE SƼǟLjY E[ɭʙXʣiʝɚ Է ʙʖɃeVWoɭk ʓUʝm poʝʁʙɨ ʏUʋʖȸeɍ ʋreaɡ Է Oʋnɍ Wɛ ʠrʑɃʑnɢ poaɭʕʖng 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 beneƤt from:

improved stock health and lower vet bills reduced soil damage, erosion, runoơ and watercourse pollution improved grass production and nutritional value reduced sward restoration costs. reduced risk of damage to environmentally sensitive areas Careful management of outǦwintered stock and equipment in order to avoid serious damage to soils and sward was undertaken on 5 ha of grassland. Regular inspections, particularly in wet weather allowed movement to betterǦdrained areas before serious poaching occurred.

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

23

NUTRIENTS & ALGAE

Management of livestock In their EuropeǦwide study into the sources of phosphorus inputs into rivers, Morse et al (1993) estimated that the most signiƤcant contributions were from livestock, human waste and fertiliser runǦoơ sources (see chart right).

NUTRIENTS & ALGAE

CDŽSE SƼǟLjY BɤՔʑɠ Sʤʢʖpɡ fʝɠ ʜXʤʢȲʑnɢ pɼɸʙXʤiʝɚ ʛiʤiJaʤiʝɚ Creation of riparian buơer strips along watercourses is perhaps the most widely recommended mitigation method for controlling diơuse pollution losses from agriculture. Consequently, research into the eƥcacy of buơer strips in reducing pollutant load entering watercourses has been extensive.

A riparian buơer strip can be deƤned as a corridor of natural vegetation between agricultural land and a watercourse. They act as barriers to surface ƪows and therefore impact on delivery of pollutants to watercourses. The rate of surface runǦoơ is slowed as the water meets resistance from vegetation and ƪows over rougher and more porous surface material.

The substantial root systems beneath the surface also increase the likelihood of inƤltration. Slower ƪowing water has a reduced capacity for the transport of particulate matter and, as a result, there is increased deposition of sediment prior to surface ƪows reaching the watercourse.

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

The Ƥndings of the many studies into the eƥcacy of buơer strip in mitigating nutrient losses from farmland are shown in the table below. These results illustrate the variability inherent in quantifying the eƥcacy of buơer strips in reducing nutrient inputs to watercourses, with the range of eƥcacy for total phosphorus varying from 30 to 95% and for total nitrogen, from 10 to 100%.

Reference AbuǦZraig et al. (2003)

Eƥcacy (% reduction) Location

Buơer Width (m)

Soil Texture

Slope (%)

Phosphorous

Nitrogen

Canada

2

Silt loam

2.3

57Ǧ64

5

47Ǧ60

10

5

65Ǧ72

15

2.3

55Ǧ93

BarƤeld et al. (1998)

USA

4.6

9

92

9.1

100

13.7

97

Barker et al. (1984)

79

99

BlancoǦCanqui et al.

(2004)

USA

0.7

Silt loam

4.9

44Ǧ63

62Ǧ77

54Ǧ72

35Ǧ36

22Ǧ53

4

77Ǧ82

82Ǧ83

81Ǧ91

54Ǧ70

71Ǧ84

8

87Ǧ91

88Ǧ90

96Ǧ99

83Ǧ84

87Ǧ95

Borin et al. (2004)

Italy

6

Sandy loam

3

78

72

Cole et al. (1994)

2.4Ǧ4.9

Silt loam

6

93

UK

4.6

Silt loam

11Ǧ16

73

27

49

9.1

93

57

56

UK

1.5

Silt loam

10

8

57

62

68

Dillaha et al. (1988)

Doyle et al. (1977)

Continued over page...

24

Reference

Eƥcacy (% reduction) Location

Buơer Width (m)

Soil Texture

Slope (%)

Phosphorous

Nitrogen

Duchemin & Madjoub

3

Sandy loam

2

85

96

(2004)

41

9

87

85

57

Edwards et al. (1983)

UK

30

Ǧ

2

47Ǧ49

Knauer & Mander (89)

Germany

10

Ǧ

70Ǧ80

50

Kronvang et al. (2000)

Denmark

0.5

Sandy loam

7

32

29

100

Norway

5

Silt loam

12Ǧ14

46Ǧ78

10

80Ǧ90

Lee et al. (2000)

7.1

Silty clay loam

5

28Ǧ72

41Ǧ64

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

France

6

Silt loam

7Ǧ15

22

47

18

89

100

Parsons et al. (1991)

USA

4.3Ǧ5.3

Ǧ

26

50

Schmitt et al. (1999)

7.5

Silty clayǦloam

6

48

35

19

15

79

51

50

Schwer & Clausen (1989)

26

Sandy loam

2

89

92

92

New Zealand

10

Ǧ

55

67

80

Norway

5

Ǧ

65Ǧ85

40Ǧ50

10

95

75

UK

12

Ǧ

4

44

36

70

Sweden

5

Ǧ

40Ǧ45

10Ǧ15

10

65Ǧ70

25Ǧ30

15

85Ǧ90

40Ǧ45

UK

27

Ǧ

4

76Ǧ96

82Ǧ94

91

Silt loam

38

Kronvang et al. (2004)

Patty et al. (1997)

Smith (1989)

Syversen (1992)

Thompson et al.

(1978) Vought et al. (1995)

Young et al. (1980) Zirschky et al. (1989)

25

NUTRIENTS & ALGAE

Buơer Strips for nutrient pollution mitigation...continued….

NUTRIENTS & ALGAE

CDŽSE SƼǟLjY Mɵɸl Crȭɰk, PʑʜnʣʉʙYʋʜiɈ SWatɏ, ǟƻA The Mill Creek catchment drains into the Stephen Foster Lake in the northern mountain region of Bradford County, Pennsylvania, USA. 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 runǦoơ into the 28 Ha lake. As a result, Pennsylvania added Stephen Foster Lake to the state’s list of impaired waters in 1996 for nutrient and sediment runoơ due to agricultural activities. Subsequently, a Total Maximum Daily Load (TMDL) for the lake that called for reductions of 49% for phosphorus was established.

Catchment management plan Several computer models were used to estimate the load reductions that might result from Best Management Practices (BMPs) being implemented. With the combination of these eơorts, the nutrient runoơ was estimated to be reduced by 52% and sediment runoơ 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 an estimated 175 kg of phosphorus (10% of the total annual load). Erosion control, to further reduce nutrient and sediment loadings to the lake, are estimated to reduce the total phosphorus load in it by an additional 10%.

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

Upstream of the lake, farmers and the Bradford County Conservation District installed 9 miles of stream fencing and alternative water supply systems to help prevent cattle from wandering into waterways.

Agricultural crossings, to swiftly move cattle across streams and prevent the animals from grazing near waterways and destroying riverbanks were also constructed.

Manure and runoơ from a previously severely degraded manure handling area is now contained and directed to the new manure storage facility for Ƥeld application.

Farm feedlot before and after infrastructure improvements.

Project partners also built 11 systems to store and treat animal waste, planted riparian buơers, and restored 2,500 feet of stream channel. The Bradford County Conservation District identiƤed over $518,000 worth of improvements to be delivered over the 11 farms.

Monitoring & Outcomes Pennsylvania Department for Environmental Protection conducted biological monitoring and analysis of Mill Creek. Across the catchment there were four sample stations collecting monthly readings for pH, conductivity, a suite of Phosphate and Nitrogen measurements, alkalinity, total suspended solids and temperature.

Growing Season Total Phosphate (TP) loads (kg) entering Stephen Foster Lake before (1994Ǧ95) and after (2004, 2005, 2006 & 2008Ǧ09) delivery of Best Management Practices

Since 2004 the growing season Total Phosphate (TP) load entering Stephen Foster Lake declined by 50 to 90% relative to the original Phase I study (1994Ǧ95) load. As a result of these reductions, the lake has been in compliance with its total phosphorus TMDL targeted, growing season load since 2005.

26

8ʠȼʑɠ TʋPʋɠ /ɪȴeɡ Fʋʢm IntʑʢɃʑnʤiʝɚ AVȿeVʣȷʑnɢ The farm is located in the Tamar Lakes Catchment and has a Ƥrst order stream which runs next to the yard. The 98 Ha of land is comprised of gently undulating pasture (60 Ha), arable (10 Ha in maize and 20 Ha in winter and spring barley) and woodland. The main farm enterprise is a dairy with 130 milkers and 50 followers. There are around 60 bull calves and the farmer has winter sheep kept over October to February. The dairy herd are housed over the winter months (September to March) and the farm has approximately 4 months slurry storage capacity. Slurries are separated into a slurry lagoon and three dirty water pits. The slurry is spread over the land by the farmer using the farm’s own machinery.

Intervention Although the farmer demonstrated several good practices, there was a problem with his slurry store, which was outdated, could not cope with the demands of the modern dairy and did not aơord the environment with enough protection against leaks and overƪowing episodes. In this instance the ‘weeping wall’ slurry lagoon was placed too close to 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 be removed and spread at appropriate times, as well as giving protection to the watercourse. The photographs below show the formalisation of the slurry pit from an inadequate weeping wall system to a concrete, bunded system in early 2008.

Monitoring Monitoring of aquatic invertebrates was undertaken and taxa scored against the BMWP scoring system (Biological Monitoring Working Party Ǧ National Water Council, 1981) to assess changes in agricultural pollution. Data was collected over the term of the project from 2007 to 2009 and further monitoring was undertaken in 2012 to assess the longǦterm eơects. Two sites one upstream and one downstream (separated by around 100m) allowed assessment of the impact of the intervention.

Results The results of the BMWP scores show that there is a signiƤcant negative impact on water quality between the upstream score (blue line) and the downstream score (red line) in the Ƥrst two samples before the intervention. After the intervention in Early 2008 (green line) the diơerence between the upstream and downstream reduces suggesting that there is little water quality diơerence between sites.

Although the 2012 upstream and downstream readings are lower than the 2008 and 2009 readings there is still little diơerence between the two suggesting that there continues to be no impact from the site in terms of water quality.

BMWP scores upstream (blue) and downstream (red) of a farmyard with an inadequate slurry pit with weeping wall. The slurry pit was updated in early 2008 (shown as an green line) after which the diơerence between the two scores reduces. Whilst 2012 Ƥgures are reduced compared to 2008 & 2009 the diơerence between upstream and downstream is less than before intervention.

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

27

NUTRIENTS & ALGAE

CDŽSE SƼǟLjY

SUSPENDED SOLIDS & TURBIDITY

ƻǟǜPNJǕ'NJ' ƻOLǏLjS & Ƽ8ƺƥǏDIǝ Y

28

SǟǜPNJǕ'NJ'

ƻOLǏLjS

&

Ƽ8ƺƥǏDIǝ Y

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

SʝuUȪeɡ Է ʣXʣȼʑndeɍ VɼʙiGɡ Numerous methods have been developed to identify the sources of suspended solids and the dynamics of sediment transport in rivers. These methods, which vary greatly in the spatial scales at which they can be applied, include:

Fine sediment risk modelling. Uses topographic, rainfall and landǦuse data to identify areas where a high propensity for the lateral ƪow of water over the land is likely to mobilise Ƥne sediment and transport it to the river.

Sediment load sampling. Water sampling to determine suspended solid load and the contribution being made by diơerent subǦcatchments.

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

Source apportionment using ƪuorescent, chemical and genetic signatures.

Pioneered by research organisations, such as ADAS Water Quality and the University of Plymouth, these approaches allow the areas of river bank or land that are contributing to the inǦchannel sediment load to be identiƤed.

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

Material from the river channel and banks Soil and other organic material washed oơ from the surface of surrounding land Particulate material from anthropogenic sources; including point sources, roads, industry and urban areas.

29

Examples of sediment being mobilised from the land surface (in this case a country road; top) and entering a watercourse (bottom).

SUSPENDED SOLIDS & TURBIDITY

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

CDŽSE SƼǟLjY SǨƮƳDŽP: A Ռȸɏ ȿeʏʖȷʑnɢ ʢisk Podɰɸʙʖng ʓUʋȷʑwʝʁk A simple and robust Ƥne sediment risk model can be extremely beneƤcial as it helps us to target and tailor both further monitoring work and catchment management interventions.

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

SUSPENDED SOLIDS & TURBIDITY

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 and transportation to receptor).

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

30

IʛpacWɡ Է ʣXʣȼʑndeɍ VɼʙiGɡ & ʤuʁʍiʏiʤɨ On the health of aquatic ecosystems The most obvious eơect of turbidity on the quality of water is aesthetic, as it gives the appearance that the water is dirty. However, suspended material in the water of rivers and lakes can also cause signiƤcant damage to the ecology of the aquatic ecosystem by blocking the penetration of light to aquatic plants, clogging the gills of Ƥsh and other aquatic organisms, and by smothering benthic habitats. This has the eơect of suơocating the organisms and eggs that reside in the interstitial spaces of the substrate.

SUSPENDED SOLIDS & TURBIDITY

Furthermore, where elevated turbidity is the result of algal or other microbial growth these organisms can also have direct toxic eơects on the ecology of the ecosystem (e.g. toxic blueǦgreen algae) or indirect eơects through the eutrophication of the water column.

Suspended material in rivers and streams can also have a signiƤcant impact on the ecological health, productivity and safety of estuarine and coastal environments in the downstream sections of their catchments.

Sediment accumulation on a riverbed

On the provision of drinking water In addition to their ecological impacts, turbidity and suspended solids also add signiƤcantly to the intensity and cost of drinking water treatment as they can accumulate in and damage water storage and treatment infrastructure.

Suspended sediment must also be eliminated from the water for eơective chlorine disinfection of the water to be achieved.

Furthermore, particulates in suspension also carry other damaging and potentially dangerous pollutants, including metals, pesticides and nutrients (such as phosphorus).

Once removed from the water, the resulting sludge, which may be contaminated with these other pollutants, must also be disposed of in a safe manner and this can be extremely costly when it is produced in large volumes.

In light of the impact that turbidity and suspended solids have on the eƥciency and cost of water treatment and on the aesthetic quality and safety of the Ƥnal drinking water, it is little surprise that the UK Water Supply (Water Quality) Regulations 2000 indicate that treated drinking water should not have turbidity above 1 NTU. In addition, the EC Directive on the Quality Required of Surface Water Intended for the Abstraction of Drinking Water 1975 (75/440/EEC) gives guidance that raw water should not have Total Suspended Solids (TSS) above a concentration of 25 mg/l without higher levels of treatment being undertaken before consumption.

In the water treatment processes undertaken at water treatment works, the suspended material in the raw water, and hence the turbidity, is removed by coagulation induced by the addition of various coagulants (e.g. alum). The level of turbidity in the raw water has a signiƤcant eơect on the coagulation process. When turbidity is elevated, the amount 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 to calibrate the dose of coagulant used in the treatment process.

31

Sediment pressure is felt at the sediment or sludge press of the water treatment works (top). This generates large quantities of sediment or sludge ‘cake’ which must then be safely disposed of (bottom). Data indicate that raw water polluted with suspended sediment can double or even triple the amount of sludge created at a works.

CDŽSE SƼǟLjY :atʑɠ qXɪʙiʤɨ & ʍiɼOoʔicɪl PʝʜiWʝʢʖng Wɛ detʑʢʛʖȸɏ ȿeʏʖȷʑnɢ ʖʛpacWɡ In 2002, a sediment ‘Ƥngerprinting’ study undertaken on 18 rivers in England and Wales revealed that 69% of the sediment load in the River Tamar was derived from landǦsurface sources and just 31% was from river channel/bank sources (see below). The study found that this ratio was in stark contrast to the Ƥndings in other Westcountry rivers. For example, in the other rivers of the wider Tamar catchment, the Tavy and Plym, just 10% and 8% of the sediment respectively 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 the catchments high stocking densities, which subject surface soils beneath pasture to severe poaching and subsequent erosion during rainstorms.

SUSPENDED SOLIDS & TURBIDITY

The provenance of interstitial sediment samples collected from study catchments in southǦwest England. Source apportionment was performed using the sediment Ƥngerprinting technique (adapted from Walling et al, 2002).

Invertebrate community assessment It has long been recognised that benthic macroǦinvertebrates are sensitive to the accumulation of Ƥne sediment in rivers (Cordone & Kelly, 1961; Chutter, 1969; Richards et al., 1997) and in recent years the Proportion of SedimentǦsensitive Invertebrates (PSI) index has been developed as a biological indicator for the assessment of Ƥne sediment accumulation in rivers. The PSI index assigns families and species of benthic macroǦinvertebrates a sensitivity rating from 0Ǧ100 for sediment according to their anatomical, physiological and behavioural adaptations. The scores for the taxa found in a sample are summed to give the sample an overall PSI score.

The development of the PSI index and its incorporation into the RIVPACS database in 2011 has allowed invertebrate sampling to be used as a biological method for the assessment of Ƥne sediment load across the Crownhill WTWs catchment.

Duplicate (two season) invertebrate samples were taken at 30 locations across the catchment. Each sample was identiƤed to species level and the PSI index calculated.

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

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

The Ƥndings of this invertebrate study (above right) show that several waterbodies in the Tamar catchment appear to have invertebrate assemblages that are impacted by Ƥne sediment. The observation that the most impacted areas are in the Upper Tamar, Ottery and Lower Tamar subǦcatchments is entirely in accordance with our previous Ƥndings and with the Environment Agency WFD Reasons for Failure database.

Water chemistry sampling To further investigate the sources of suspended solids in the Tamar catchment, a telemetrically linked multiǦparameter probe (sonde) was installed to identify occasions when heavy rainfall had triggered highǦƪow events in the river and a corresponding spike in the turbidity of the river had occurred.

Water quality samples were then taken and analysed to identify the relative suspended solids contribution being made by each subǦ catchment at those times (right).

32

Seʏʖȷʑnɢ ʛiʤiJaʤiʝɚ ȷeaʣureɡ & ʃȱʑʖɠ eɑ£caʎɨ

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 overǦwinter tramlines Loosen compacted soil layers in grassland Ƥelds Reduce Ƥeld stocking rates when soils are wet Construct troughs with a Ƥrm but permeable base Move feeders at regular intervals

SUSPENDED SOLIDS & TURBIDITY

There are a wide range of mitigation measures available for reducing sediment loads and turbidity in the aquatic environment. These measures are primarily aimed at reducing the availability of sediment sources, at reducing the likelihood of material being mobilised and at disconnecting the pathways via which particulate matter (mainly soil) is carried into watercourses. Measures include:

Blonder1984

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

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

The table below summarises the key Ƥndings from the Mitigation Options for Phosphorus and Sediment (MOPS) project— a collaborative research project, funded by the UK Department for Environment, Food and Rural Aơairs (DEFRA), and involving four project partners, Lancaster University, ADAS, the University of Reading and The Game & Wildlife Conservation Trust Allerton Project. The project was designed to test the eƥciency of a range of mitigation measures aimed at reducing sediment through conservation tillage techniques.

Mitigation measure

Reduction in suspended sediment

Contour cultivation

64Ǧ76%

Minimum tillage

37Ǧ98%

Tramline modiƤcation

75Ǧ99%

Beetle bank construction

16Ǧ94%

Amanda Slater

A subǦsoiler (top) and a rough cultivation (bottom) Ǧ both good methods for maintaining good soil structure throughout the year

Summary of key Ƥndings from the Mitigation Options for Phosphorus and Sediment (MOPS) project that aimed to test the eƥciency of a range of mitigation measures aimed at reducing sediment through conservation tillage techniques. (From Stevens and Quinton, 2008.)

CDŽSE SƼǟLjY 'ʖrecɢ ʏʢɵɸʙʖng: Ɉ ʛʖʜʖʛum ʤɵɸOaȰɏ teɭʕʜiqɂɏ Direct drilling is a system of seed placement where soil is left undisturbed with crop residues on the surface from harvest until sowing. Seeds are delivered in a narrow slot created by discs, coulters or chisels.

Direct drilling oơers the potential for savings over traditional ploughǦbased crop establishment systems due to lower costs associated with machinery, energy, soil damage, soil erosion, nitrogen leaching and agrochemical losses. It also oơers substantial environmental beneƤts, such as increased soil fauna and habitats for birds, as well as a reduced risk of watercourse pollution.

The Soil Management Initiative (SMI) Guide to Managing Crop Establishment says the method gives ‘a dramatic reduction in establishment costs and an increase in work rate, improved control of black grass and reduced slug activity’ Source CranƤeld University

System

Depth (cm)

Cost (£/ha)

Time (mins/ha)

Cereal yield (%)

Plough

15Ǧ35

100Ǧ135

150Ǧ220

100

0

30Ǧ45

25Ǧ40

99.2

Direct drilling

33

CDŽSE SƼǟLjY BɤՔʑɠ Sʤʢʖpɡ fʝɠ ȿeʏʖȷʑnɢ pɼɸʙXʤiʝɚ ʛiʤiJaʤiʝɚ As we have described for nutrient pollution, the eƥcacy of buơer strips in reducing suspended sediment loads in watercourses has also been the subject of a signiƤcant body of research. The Ƥndings of this research, summarised in the table below, indicate that buơer strips can reduce sediment losses from between 33 and 100% in plot and Ƥeld experiments and that percentage reduction is primarily inƪuenced by buơer strip width.

Location

Buơer Width (m)

Soil Texture

Slope (%)

Eƥcacy (% Sediment reduction)

Arora et al. (1996)

USA

1.52

Silty clay loam

3

40Ǧ100

BlancoǦCanqui et al.

Reference

SUSPENDED SOLIDS & TURBIDITY

USA

0.7

Silt loam

4.9

81Ǧ92

(2004)

4

94

8

98Ǧ99

Borin et al. (2004)

Italy

6

Sandy loam

3

93

Dillaha et al. (1988)

UK

4.6

Silt loam

11Ǧ16

63

9.1

78

Duchemin & Madjoub

3

Sandy loam

2

87

(2004)

9

90

Ghaơarzadeh et al. (92)

9.1

7Ǧ12

85

USA

61

80

Denmark

0.5

Sandy loam

7

62

29

100

Norway

5

Silt loam

12Ǧ14

60Ǧ87

10

90

Lee et al. (2000)

7.1

Silty clay loam

5

70

Lim et al. (1998)

Homer & Mar (1982) Kronvang et al. (2000)

Kronvang et al. (2005)

USA

6.1

Silt loam

3

70

12.2

89.5

18.3

97.6

Lynch et al. (1985)

30

75Ǧ80

USA

19

4

62

17

6

38

4

4

64

UK

9.2

Sandy loam

Ǧ

72

Jin et al. (2002)

Magette et al. (1987) McKergow et al. (2003) Muenz et al. (2006) Patty et al. (1997)

Australia

Loamy land

<2

93

USA

25

Sandy clay loam

16.5

81

France

6

Silt loam

7Ǧ15

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

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

67Ǧ79

Ziegler et al. (2006)

Thailand

30

Sandy loam

34Ǧ87

Smith (1989)

34

PESTICIDES

PNJSƼIǨǏ'NJS

35

PNJSƼIǨǏ'NJS 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 according to their target organisms and include herbicides (weeds), insecticides (insects), fungicides (fungi), nematocides (nematodes) and rodenticides (vertebrate poisons).

MCPA (herbicide)

Mecoprop (herbicide)

In agricultural applications, pesticides are widely used to protect crops and livestock from pests and diseases and, when used with care, they can deliver substantial beneƤts for society: increasing the availability of good quality, reasonably priced food and well managed urban environments.

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

SʝuUȪeɡ Է ȼeVʤiʎideɡ Pesticide pollution occurs primarily through two routes:

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

Diơuse agricultural sources. Where active ingredients are washed oơ or leached from the soil following their application.

PESTICIDES

The threat posed by an individual pesticide is also dependent on the unique intrinsic properties of the active ingredients, which determine the speciƤc risk they pose in terms of water pollution and the ease of their subsequent removal from drinking water. These intrinsic properties include: Cyromazine (insecticide)

Pesticide halfǦlife. The more stable the pesticide, the longer it takes to break down and the higher its persistence in the environment.

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

36

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

Rainfall. High levels of rainfall increases the risk of pesticides contaminating water.

Water moving across or through the soil can wash pesticides into watercourses or they 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 and this degradation is expedited where the levels of microbial activity are high due to the presence of high numbers of microbes or elevated soil temperature. Pesticide residues can also be degraded through evaporation and photoǦdecomposition.

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

Treatment surface. Pesticides are generally designed to be applied to soilǦbased systems where they are held before being taken up by the target organism. When pesticides are applied to nonǦporous surfaces (such as concrete or tarmac) or to soil that is degraded, they are not absorbed by the soil and are therefore particularly vulnerable to mobilisation into watercourses following rainfall.

CDŽSE SƼǟLjY The principal aim of this approach is to identify areas where the use of pesticides applied to the land represents a pollution risk due to an elevated likelihood that they will be mobilised and transported through or over the soil and into a watercourse.

A number of proprietary tools and modelling approaches have been developed to assess the spatial risk of pesticide pollution. These include the CranƤeld University CatchIS tool, the ADAS Pesticide Risk Assessment Model and the GfK Kynetec iǦMAP Water system, but all are essentially based on similar conceptual models.

We used the iǦMAP Water system to model pesticide application rates across the subǦcatchments of the Tamar catchment. It is generally accepted that, while the iǦMAP dataset is robust at catchment or subǦcatchment scale, its aggregation to a Ƥner scale than the subǦcatchment level would result in signiƤcant inaccuracy in the Ƥnal model.

To achieve our modelling aim we developed a spatial mapping protocol (summarised right), which is essentially based on the application rate of the pesticide (derived from the iǦMAP system), the landuse for which it is used, the propensity of the soil to release pesticides by leaching or runǦoơ, and the hydrological connectivity of the land.

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

37

PESTICIDES

AVȿeVʣʖng ȼeVʤiʎidɏ pɼɸʙXʤiʝɚ ʢisk Xʣʖng Ɉ ʣpaʤiɪl Podɰl

CDŽSE SƼǟLjY AVȿeVʣʖng ȼeVʤiʎidɏ pɼɸʙXʤiʝɚ Ooaɍ Xʣʖng paVʣʖɃɏ Vʋʛɿʙʖng Taking samples of river water using the conventional method of Ƥlling bottles by hand can be costly and timeǦconsuming. The results obtained from these ‘spot’ samples can, at best, only provide a snapshot of the concentration target compounds which may be present at the time of sampling.

Subsequent interpretation of the analytical results obtained is also diƥcult (was it the leading edge of a pollutant plume, the peak, or the trailing edge?) and the time lag between these results and repeat samples or remedial action inevitably means the environmental investigation is reactive in nature.

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

Recently, a research collaboration between South West Water, the University of Portsmouth, Natural Resources Wales and the Westcountry Rivers Trust has been established to use the ChemcatcherTM passive sampler (developed at the University) to investigate water quality in this area.

PESTICIDES

Chemcatcher™ is a small plastic device Ƥtted with a speciƤcally tailored receivingǦ phase disk that has a high aƥnity for the target compounds of interest. Diơerent phases are available to sequester nonǦpolar (e.g. polyǦaromatic hydrocarbons and some pesticides) and polar pollutants (e.g. pharmaceuticals and personal care products), heavy metals (e.g. cadmium, copper, lead and zinc) and some radioǦ nuclides (e.g. caesium).

In practice, the receiving phase disk is overlaid with a thin diơusionǦlimiting membrane. These devices can be used to obtain the equilibrium concentration of the pollutants or more typically the timeǦweighted average (TWA) concentration over the sampling period.

The Ƥrst riverine trials using the ChemcatcherTM involved investigating pesticides along the River Exe; a river designated as a WFD Article 7 Drinking Water Protected Area (DrWPA) with additional Safeguard Zone (SGZ) status that requires a formal ‘action plan’ to be drawn up by the Environment Agency. Here the aim was to ‘Ƥeld test’ the technique and hopefully provide an understanding of where the worst problem pesticide loadings and locations were.

Over a twoǦweek period in early May 2013, timed to coincide with known agricultural applications and forecasted rainfall, a number of devices were deployed along much of the length of the river.

ChemcatcherTM samplers were housed in a number of specially fabricated metal cages supplied by Anthony Gravell, Technical Specialist at Natural Resources Wales Llanelli Laboratory, who specialises in passive sampling in conjunction with HPLCǦMS techniques for the analysis of pesticides, pharmaceuticals and endocrine disruptors in various environmental compartments. Each cage held three replicate sampling devices and was weighted to ensure stability (see images right).

Prior to the trials, researchers at the University and South West Water’s Organics Laboratory worked together to identify a receiving phase disk capable of sequestering a group of nine speciƤc pesticides that are commonly detected in raw waters in the South West.

Prior to the Ƥeld deployment, laboratory tests were undertaken using a large tank Ƥlled with River Exe water and spiked with known concentrations of the pesticides under investigation. Here the aim was to measure the uptake kinetics (and hence the sampler uptake rates) of these chemicals over a twoǦweek period. Once these data were available, they were then used to estimate the TWA concentrations of these pollutants in the river over the Ƥeld trial period.

38

IʛpacWɡ Է ȼeVʤiʎideɡ On the health of aquatic ecosystems Pesticides contain active ingredients designed to kill certain groups of organisms and, as such, there is signiƤcant potential for them to pose a threat to the health of other nonǦtarget species (including humans), habitats and ecosystems when they accumulate in the environment.

Direct eơects of pesticides on vertebrates have been greatly reduced since the phasing out of organochlorines, but there are a number of active ingredients, such as the molluscicide methiocarb, which have been shown to exert toxic eơects on vertebrate nonǦtarget species (Johnson et al., 1991).

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

Other studies (Williams et al., 1995) have shown that pesticide ƪushes can occur at the headwaters of streams, where stream fauna could be aơected. This is of particular concern because such waters are otherwise of high quality and may be Ƥsh nursery grounds.

As a result of these Ƥndings, the Water Framework Directive sets thresholds for many key pesticides, such as Diazinon, Linuron and Cypermethrin, above which they may be expected to be damaging the aquatic environment and/or pose a threat to human health (soǦcalled ‘speciƤc pollutants’). The WFD also sets targets for several high toxicity (and largely banned) pesticides, such as Atrazine and DDT, which are classiƤed as ‘priority’ or dangerous substances under the EU Dangerous Substances Directive.

CDŽSE SƼǟLjY AVȿeVʣʖng ȼeVʤiʎidɏ pɼɸʙXʤiʝɚ ʠreVʣurɏ Xʣʖng ʋɚ ʖʜɃɏԮɰʍUatɏ ʖndʑx: ǜPƩAR Another approach we have adopted is the assessment of invertebrate assemblages using the newly developed SPEcies At Risk Ǧ Pesticides (SPEARPESTICIDES) index (Liess and von der Ohe, 2005). This index assesses the degree to which the invertebrate assemblages in the river are being aơected by the presence of pesticides (and insecticides in particular) using the lifeǦhistory 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 excellent indicator of pesticide pressure across a catchment in a way that water quality sampling cannot achieve unless undertaken with very high frequency.

In 2011, the SPEARPESTICIDES index was also added to the River InVertbrate Prediction and ClassiƤcation System (RIVPACS) database and this facilitated its use in the same year as a biological method for the assessment of pesticide pressure across the Crownhill water treatment works catchment.

Invertebrate samples taken across the catchment were identiƤed to species level and the SPEARPESTICIDES index calculated. The River Invertebrates Analysis Tool (RICT) was then used to predict what the SPEARPESTICIDES index score should have been for that site and the Ecological Quality Ratio (EQR) for the sample calculated as the ratio between the observed and the expected (O/E) score.

The Ƥndings of the Crownhill WTWs catchment SPEARPESTICIDES invertebrate study are summarised in the map (right).

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PESTICIDES

Most recently, in 2013, an extensive analysis of the eơects of pesticides on communities of stream invertebrates in Europe and Australia found that they caused signiƤcant eơects on both the species and family richness, with losses in species richness of up to 42% recorded (Beketov et al., 2013).

Advanced water treatment solutions required to remove pesticides from drinking water include powdered activated carbon (top), granular activated carbon (GAC) Ƥlters (middle) and ultraƤltration (bottom).

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

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

There are several methods available for the removal or reduction of pesticide concentrations in treatment of drinking water. Blending with water from an unǦ contaminated source can be eơective as can blending treated water, but these methods often require lengthy and costly transfers of water or are simply not feasible.

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

Granular activated carbon (GAC) Ǧ adsorption Powdered activated carbon (PAC) Ǧ adsorption OzoneǦGAC – destruction/adsorption/biological Ultraviolet irradiation Ǧ destruction Advanced oxidation Ǧ destruction NanoǦƤltrationǦreverse osmosis – physical removal (size exclusion)

PESTICIDES

All of these processes are expensive to undertake, in terms of both the infrastructure investment required and their running costs, and all are highly energy and resource intensive.

Furthermore, there are a number of pesticides for which these highǦintensity processes can remain ineơective (such as metaldehyde; see below) and there remains a considerable risk that these contaminants could still be passed on into the Ƥnal treated water supplied to customers if further precautions are not taken.

Metaldehyde is a selective pesticide used by farmers and gardeners to control slugs and snails in a wide variety of crops. Technically it is known as a ‘molluscicide’ and its action is very speciƤc to slugs and snails) Metaldehyde is sold under a variety of brand names in pellet form.

Metaldehyde is an issue for water companies, because pellets applied to crops on land can Ƥnd their way into drains and water courses either directly during application or as a result of run oơ during high rainfall events. Levels of metaldehyde have been detected in trace concentrations in the rivers or reservoirs at levels above the European and UK standards set for drinking water. Current drinking water treatment methods are not eơective at reducing the levels of metaldehyde in water. There have been occasions when very low levels of metaldehyde have been detected in treated drinking water. These levels are extremely low – the highest being around 1ug/l and mostly much lower. However the levels are above the European and UK standards for pesticides in drinking water that is set at 0.1ug/l.

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PeVʤiʎidɏ ʛiʤiJaʤiʝɚ ȷeaʣureɡ & ʃȱʑʖɠ eɑ£caʎɨ High pesticide inputs to watercourses are most likely to occur due to direct application or when rainfall causes surface runǦoơ or leaching shortly after application. Mitigation measures to reduce pesticide inputs therefore fall into three main categories:

Best practice advice and education. Encouraging measures to prevent direct application or pointǦsource loss of pesticides to a watercourse or drainage system.

Land management and soil management advice. Soil management measures to prevent rapid runǦoơ or leaching which ensure that pesticides are taken up by target species or broken down in the soil rather than being available to cause pollution.

Landuse change and the improvement of farm infrastructure. Mitigation measures

Pesticide best practice advice & education Many pesticide contaminations occur as the result of poor practices undertaken during their transportation, storage, preparation or application. These so called pointǦsource inputs of agricultural pesticides mainly occur from hard impermeable surfaces (such as farmyards, storage facilities or roads), which become contaminated during the Ƥlling and cleaning of sprayers, improper disposal of unǦused mix, leaks from faulty equipment, incorrect storage of canisters and washing of equipment.

Once present on these surfaces pesticides are then available to be washed into an adjacent watercourse or to enter the sewerage system, which then transports them to the sewage treatment works and on into the aquatic environment via the works discharge. Direct contamination of the aquatic environment can also occur as the result of spray drift or when pesticide application is inaccurate and occurs outside the conƤnes of the target Ƥeld.

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

CDŽSE SƼǟLjY Tȱɏ VɼʙunWʋʢɨ IʜiʤiaʤʖɃɏ The Voluntary Initiative (VI) began in April 2001. It is a UKǦwide package of measures, agreed with Government, designed to reduce the environmental impact of the use of pesticides in agriculture, horticulture and amenity situations. Initially a list of 27 proposals, the programme Ƥnally included over 40 diơerent projects covering research, training, communication and stewardship.

The combined cost of the programme between 2001 and 2006 to the farming industry, the crop protection industry, the water industry and others was estimated to be £45Ǧ47m, but during that time they worked to:

Improve awareness among farmers of the potential environmental risks arising from pesticide use; improve the competence of advisors and improve Ƥeld practices of spray operators and optimise the performance of their machines.

Engage the farming unions and establishment of Crop Protection Management Plans (CPMPs) as a selfǦaudited means of assessing and planning the environmental aspects of crop protection activities across the whole farm.

Establish a lowǦcost sprayer testing scheme (NSTS) with a nationwide network of 294 testing centres and 465 certiƤcated testers.

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

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

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There are a number of comprehensive guides on good/best practices to be undertaken when using pesticides, including the Code of Practice for Using Plant Protection Products (below).

PESTICIDES

(e.g. buơer strip and riparian wetlands) designed to intercept surface runǦoơ and ensure pesticides are broken down before reaching the watercourse.

Perhaps the simplest method for the reduction of pointǦsource pesticide pollution is to reduce the number of sprayer Ƥlling and cleaning actions undertaken by encouraging farmers to share the use of spraying equipment. In addition, numerous studies have found that the adoption of good or best practices when using pesticides can ensure that the risk of environmental contamination is minimised (Kreuger and Nilsson, 2001).

The best management practices shown to be eơective include Ƥlling and cleaning sprayers only on the Ƥeld or on a biobed (Felgentreu and Bischoơ, 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 the Ƥeld (Jaeken and Debaer, 2005), and no application of pesticides on the farmyard.

A pesticide handling area is the site where the sprayer is Ƥlled and is often also used for sprayer washing, nozzle calibration, sprayer testing, maintenance and storage.

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

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

Another powerful method for the collection and disposal of pesticideǦcontaminated water is the biobed. A biobed consists of a pit or container Ƥlled with a mixture of chopped straw, peat and topsoil that rapidly degrades any pesticide entering the bed through microbial activity.

PESTICIDES

Liquids enter the biomix within the biobed by gravity drainage or a pump.

Once there they then undergo bioremediation before being drained from the biobed. This drained liquid, which contains minimal pesticide residues, can be used for land irrigation or reǦused e.g. for subsequent sprayer washing.

CDŽSE SƼǟLjY MiʤiJaʤʖng ȼeVʤiʎidɏ pɼɸʙXʤiʝɚ ʖɚ 'ʢɔԲ ReȿʑʢYʝʖɠ, Cʝʢʜwɪɸl Over the period 1996Ǧ2010, South West Water’s Drift Water Treatment Works recorded a steady increase in both the number of pesticide detections per annum and the detected concentration of individual pesticide compounds in both the raw and Ƥnal water. During this period there were 54 positive detections for pesticides in the raw water within Drift Reservoir representing 14 diơerent compounds.

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

Concurrently, funding of £100,000 was invested in a programme of landowner engagement, agricultural training, and farm intervention work upstream of the reservoir, to address these rising chemical detections at source. These interventions are being delivered in the catchment through Cornwall Wildlife Trust’s Wild Penwith Project, which is working in partnership with South West Water to provide landowners across the Drift catchment with a number of advisory, educational and infrastructure 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 landowners across the Drift catchment with:

OneǦtoǦone farm advisory visits, including an assessment of current farm practices, and provision of water protection best practice;

Free agricultural training events, such as weed management; A capitalǦgrant award, funding, for example, improved pesticide handling and storage areas.

In February 2013, Wild Penwith ran a weed management training day on a dairy farm adjacent to Drift Reservoir.

Following presentations on the cultural, mechanical and chemical control of weeds, local farmers visited the water treatment works at Drift to learn more about the complexities of drinking water treatment.

Peter James, who farms at Little Sellan adjacent to Drift Reservoir said, “As a farmer, I am very pleased that South West Water is taking this proactive approach in our river catchment. We are now more aware of both the water companies business, and how important our activities on the farm are to the drinking water treatment process. I believe working in partnership in this way will be of beneƤt to everyone.”

PESTICIDES

These farm activities are supported by a comprehensive programme of water chemistry sampling (monitoring herbicides, insecticides and fungicides) on the reservoir’s two feeder streams. Water samples are regularly collected with the consent and coǦoperation of each landowner involved.

FollowǦup samples can be taken from a wider network of additional farms as required. Using this system, the source of any inǦreservoir or inǦriver pesticide detection can be traced back to individual farm holdings and advice and guidance given to mitigate the problem.

Land managers are then made aware of the drinking water issues, and oơered oneǦtoǦone water protection best practice advice and other farm interventions from the Wild Penwith team as appropriate. In addition to this chemical monitoring programme, biological monitoring has also been undertaken in the catchment, including the assessment of macroǦ invertebrates, macrophytes (large aquatic plants) and diatoms (benthic algae).

Minimising the levels of pesticides found in the raw water could result in South West Water savings on treatment plant operating costs. Wider environmental gains include improved wetland and stream habitat quality, and associated enhanced biodiversity.

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

Through the wider Wild Penwith Living Landscape project, Cornwall Wildlife Trust staơ gained the respect and trust of local farmers, which enables them to tackle these important drinking water quality issues together.

Further info: www.cornwallwildlifetrust/wildpenwith

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Land management & soil advice It has been widely demonstrated that any improvements in soil or land management, such as implementation of conservation tillage techniques, that reduce the risk of runǦ oơ and soil erosion are also likely to reduce the risk of a pesticide being mobilised following its application to the land. In addition, the incorporation of organic material into the soil has also been shown to increase the sorption of some pesticides; reducing their mobility and the likelihood that they will be lost through leaching.

Riparian buơer strips and ‘conservation headlands’ can reduce pesticide damage to adjacent natural habitats.

Interestingly, several studies have shown that the presence of subǦsurface land drainage also reduces the loss of pesticides through surface runǦoơ. This Ƥnding is supported by hose of a study of autumnǦapplied pesticides on clay loam soils in north east England where losses from an unǦdrained plot were found to be up to 4 times larger than from a moleǦdrained plot (Brown et al., 1995).

In contrast to these Ƥndings, however, it is also important to note that there is considerable evidence that over eƥcient drainage may also generate signiƤcant loss of pesticides through leaching and drain ƪow. The risk factors that lead to pesticide loss through leaching and drainage are poorly understood, but it seems that active ingredient mobility, application rate, soil type and rainfall may all contribute to the generation of pollution via this route.

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

Landuse change & the improvement of farm infrastructure Perhaps the most studied interventions for the mitigation of diơuse pesticide pollution are buơer strips around Ƥelds (conservation headlands), riparian buơer strips and constructed wetlands.

PESTICIDES

These features not only reduce the risk of spray drift contaminating adjacent habitats and watercourses, but they also act to disconnect pesticide pollution pathways by promoting the inƤltration of runǦoơ waters carrying them into aquatic environments.

CDŽSE SƼǟLjY BɤՔʑɠ Sʤʢʖpɡ fʝɠ ȼeVʤiʎidɏ pɼɸʙXʤiʝɚ ʛiʤiJaʤiʝɚ As we have described for nutrient and sediment pollution, the eƥcacy of buơer strips in reducing pesticide losses to watercourses has also been the subject of a signiƤcant body of research (mainly at plotǦ or ƤeldǦscale). The Ƥndings of this research, summarised below, indicate that buơer strips can be highly eơective in mitigation of pesticide pollution.

In one of the most comprehensive reviews undertaken on the eơectiveness of buơer strips in the mitigation of pesticide pollution, Reichenberger et al. (2009) summarised the Ƥndings of 14 publications that between them assessed the performance of 277 diơerent buơer strips. The pesticide load reductions for active ingredients in solution (below left, 63 data points) and bound to sediment (below right; 214 data points) are summarised below.

Overall, buơer strips of all widths were found to be eơective in the mitigation of pesticide loss from Ƥelds and were especially eơective when they were vegetated and when runǦoơ ƪow was slowed suƥciently to enable water inƤltration.

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MICROBES & PARASITES

ƳIǨƺƵBNJS & ƸAƺDŽƻITNJS

45

MIǨƺƵBNJS & PAƺDŽƻITNJS Two principal bacterial groups, coliforms and faecal streptococci, are used as indicators of possible sewage contamination in water because they are commonly found in human and animal faeces. Although these bacteria, which are often referred to as faecal indicator organisms (FIOs), are not typically harmful themselves, they do indicate the possible presence of pathogenic (diseaseǦcausing) bacteria, viruses, and protozoans that also live in human and animal digestive systems.

Cryptosporidium oocysts under a ƪuorescence microscope.

Another group of microbial pollutants derived from human and animal faecal material which pose a signiƤcant risk to human health, either when people come into contact with the river water or when contaminated water is abstracted for drinking water treatment, 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 intestinal epithelial tissue. The resulting condition, Cryptosporidiosis, is typically an acute shortǦ term diarrheal disease but it can become severe and chronic in children and in other vulnerable or immunoǦcompromised individuals. In humans, Cryptosporidium can persist in the lower intestine for up to Ƥve weeks; from where it continues to shed oocysts into the environment.

Bacteria Escherichia coli.

MICROBES & PARASITES

SʝuUȪeɡ Է ʛiʎUɼʍiɪl cʝnWʋʛʖnaʤiʝɚ The most commonly tested faecal bacteria indicators are total coliforms, faecal coliforms, and faecal streptococci. Total coliforms are a group of bacteria that are widespread in nature and which occur in many materials including human faeces, animal manure, soil, and submerged wood. The usefulness of total coliforms as an indicator of faecal contamination therefore depends on the extent to which the bacteria species found are faecal and human in origin.

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

Faecal coliforms are a subset of the total coliform bacteria and are more speciƤcally faecal in origin. Faecal streptococci also occur in the digestive systems of humans and other warmǦblooded animals. In the past, the ratio between the level of faecal streptococci and faecal coliforms was used to determine whether bacterial contamination was of human or nonhuman origin and, while no longer recommended as 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 faecesǦ derived substances (e.g. ammonia) make their way into a watercourse. These include:

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

WashǦoơ and leaching of manure or slurry on the land surface or accumulated on yards or tracks.

From consented or unǦconsented discharges of untreated human sewage.

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Unrestricted access of livestock to a watercourse

When considering microbial contamination is it important to examine the contribution that these diơerent potential sources make to the load in the water column in any particular location.

Analysis of data from 205 river and stream sampling points spread widely across mainland UK has shown that microbial load is typically correlated with high ƪow rather than low ƪow condition and that urban and grassland landscapes make the most signiƤcant contribution to the load (Kay et al., 2009).

Further studies have also shown that faecal indicator organism (FIO) loads in catchments with high proportions of improved grassland were shown to be as high as from urbanised catchments and in many rural catchments ι40% of FIO may be derived from agricultural sources (land surface and farmyard infrastructure).

This strong correlation between high ƪow and contamination levels has also been shown to be the case for cryptosporidium and outbreaks of cryptosporidiosis are strongly linked to an animal to human transmission pathway following periods of heavy precipitation (Lake et al., 2005).

Interestingly, in contrast to these Ƥndings of Kay et al, a detailed study of the River Ribble catchment undertaken in 2002 found that over 90% of the total FIO load entering the Ribble Estuary was discharged by sewage related sources during high ƪow events.

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

IʛpacWɡ Է ʛiʎUɼʍiɪl cʝnWʋʛʖnaʤiʝɚ On the health of aquatic ecosystems When animal and human faecal material and the microbes it contains, enter a river system they can exert severe negative impacts on the ecological health of the ecosystems locally and further down the catchment in a number of ways.

First, the elevated levels of turbidity reduce the levels of light penetrating the water column and this can aơect the plant communities present in the system. This can be particularly problematic in the deeper and ecologically sensitive waters of the estuaries and coastal regions at the bottom of a river catchment.

More signiƤcantly, however, is the eơect that the metabolic activity of aerobic bacteria decomposing 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 are high the Biological Oxygen Demand (BOD) in the water will be elevated and the levels of 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 ecological health of the river ecosystem will be degraded as Ƥsh and invertebrate communities begin to suơer.

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eutrophication&hypoxia

MICROBES & PARASITES

It is assumed that the remaining load at times of high ƪow is derived from point sources such as sewerage treatment works, misconnections in the sewerage system and combined sewer overƪows (which discharge when sewage treatment works reach their maximum treatment capacity).

On the provision of drinking water, recreation & Ƥsheries The total level of microbial contamination in water and the level of diơerent faecesǦ derived bacteria are both used as indicators of the potential pathological risk posed by that water. In addition, faecal material may also contain other pathogenic organisms, such as Cryptosporidium, which cause gastrointestinal infections after ingestion or others which cause infections of the respiratory tract, ears, eyes, nasal cavity and skin.

Cryptosporidiosis (the Cryptosporidium pathogenic lifecycle) (top) and a micrograph showing cryptosporidium oocysts alongside Giardia lamblia (another parasite) (bottom).

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

As a result of this threat, signiƤcant steps must be taken at the water treatment works to remove microbial contaminants from drinking water. There are a number of methods for the disinfection and Ƥltration of drinking water and all must be undertaken with increased intensity if the microbial load in the abstracted raw water increases signiƤcantly at certain times.

The EC Drinking Water Directive also requires that drinking water should not contain any microǦorganism or parasite (such as Cryptosporidium) at a concentration that would constitute a potential danger to human health. Cryptosporidium is particularly adept at breaking through the standard suite of treatment processes undertaken at many works (such as sand Ƥltration and chlorination) and the Drinking Water Inspectorate now requires water companies to implement raw water monitoring, to undertake comprehensive risk assessments and to design and continuously operate adequate treatment and disinfection for cryptosporidium.

In addition to these increased demands for disinfection, it is also important to note that the presence of elevated levels of faecal material also make a signiƤcant contribution to the turbidity and suspended solid load in the raw water. As already described previously the levels of turbidity in the raw water are used to calibrate the water treatment process and, when elevated, will increase the costs of coagulation and sludge management processes undertaken at the drinking water treatment works.

CDŽSE SƼǟLjY Baʃʕʖng watʑɠ VWʋnGʋUGɡ ʖɚ ʃȱɏ ǟK

MICROBES & PARASITES

The European Union began work to regulate the provision of clean and healthy bathing waters 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 of failing the standards set out in the European Bathing Water Directive are the responsibility of the Environment Agency. They take weekly water samples from over 500 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 when pathogenic microbes may be present in the water.

Prior to 2012, water samples taken at bathing waters were analysed for Total coliforms, Faecal coliforms and Faecal streptococci; however this has changed in preparation for the revised bathing water directive, which sets more stringent water quality targets to achieve by 2015.

In addition to improving water quality at bathing waters the revised Directive also places much greater emphasis on managing beaches and providing information. From 2016, Bathing Water Controllers (any local authorities, water companies and businesses in control of the land immediately next to bathing waters where people swim) will also have to provide information to the public about the quality of their bathing water and advise people if there has been a pollution incident.

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MiʎUɼʍiɪl ʛiʤiJaʤiʝɚ ȷeaʣureɡ & ʃȱʑʖɠ eɑ£caʎɨ There are numerous highly eơective methods designed to reduce the microbial contamination of watercourses, estuaries and coastal waters. Which of these measures is required depends entirely on the sources from which the contamination is derived in a particular catchment.

The Westcountry Rivers Trust farm measure factǦsheets can be found at— http://tinyurl.com/kqpyctv.

If a domestic sewage treatment works or septic systems are found to be discharging signiƤcant levels of faecal material and bacteria into a watercourse then the addition of further ‘tertiary’ treatment processes, such as disinfection may be required to remove high levels of bacteria from the eƫuent discharged.

Where the contamination is the result of untreated eƫuent discharges from combined sewer overƪows (CSOs) or poorly functioning (misconnected) sewerage infrastructure, only increased sewage storage or treatment capacity at the works or investment in infrastructural improvements may be capable of reducing these impacts. This type of remedial work can have signiƤcant cost implications for the individuals or the water company responsible for the infrastructure (see below).

Mitigation measures for reducing microbial contamination in watercourses derived from diơuse agricultural sources include :

Reduction in livestock stocking rate Creation of riparian buơer strips Creation of wetlands or reedbeds Exclusion of livestock from watercourse and provision of alternative drinking sources 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 Ƥelds at highǦrisk times

CDŽSE SƼǟLjY Tȱɏ Cȵeʋɚ SɄȭʑɞ PUʝjecɢ Before South West Water (SWW) was privatised in 1989, little had been done to protect the coastal bathing waters of the South West, and the region’s reputation was suơering as a result. In 1990, the UK Government adopted higher water quality standards imposed by the European Union, making the need for change even more critical. Starting in 1992, SWW’s response to this was Clean Sweep – the largest environmental programme of its kind in Europe.

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

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

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

Since Clean Sweep ended in 2010, SWW have continued to develop their strategic plans for the delivery of environmental improvements and sustainability. Most recently, they have been working in partnership to locate and remediate misǦconnections in Torbay, Bude and Plymouth.

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More information: www.beachlive.co.uk

MICROBES & PARASITES

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

CDŽSE SƼǟLjY Tʝʁbʋɨ Baʃʕʖng :atʑɠ IʛʠUʝɃʑȷʑnɢ PUʝjecɢ Initiated and funded by South West Water in 2010 and delivered by the Environment Agency working in partnership with Torbay Council, the Torbay Bathing Water Improvement Project aims to reduce the levels of pollution in Torbay's streams and improve bathing water quality. In particular, the project has focused on locating and remediating drainage and sewage misǦconnections that are leading to pollution.

The project has focused on Ƥve resort beaches, key to the local economy, which are at risk of failing to meet the new standards set out by the Revised EC Water Directive from 2015. These beaches were Torre Abbey, Hollicombe, Preston, Paignton and Goodrington.

MisǦconnections Over one hundred misconnected properties have been identiƤed through the project, which have all been discharging foul or dirty water into streams through surface water systems. 80% of the misǦconnections found have now been resolved and connected to foul sewer.

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

Commercial inputs have also been an issue; including a hotel, car wash, two cafes, a supermarket, doctors surgery, oƥces and a factory. Other issues such as dog and bird fouling, waste from boats, sewerage infrastructure and council operations are all being looked at as part of the project.

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

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

MICROBES & PARASITES

Working with the hotel owners and South West Water, the issue was identiƤed and resolved with a considerable improvement in water quality in the stream, as shown in the chart (right).

In other locations six houses were found discharging into the Torre Abbey and Cockington Streams and a blocked private manhole was allowing foul water from two ƪats to discharge to the sea via an unǦsampled surface water system.

120

Problem fixed

100 Cell count (000's /100ml)

SigniƤcant Ƥndings In one Torquay hotel a blockage in a main foul sewer line was leading to considerable pollution of the Cockington stream.

80 60

Faecal Coliforms/100ml

40 20 0

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

Next Steps Such was success of the Torbay project that additional funding has now been secured and the focus will be extended to include two further catchments in Torbay; the Torre Abbey Stream and the Kirkham Stream, which both remain aơected by as yet unknown pollution sources.

Paignton Beach

In addition, the project will also produce an engagement plan, designed to advise and educate both the public and tradesmen, to reduce the likelihood of further misǦ connections in the future. There is also be a drive underway to share best practice from the project with other local authorities to help improve other ‘at risk’ bathing waters in locations such as Bude (north Cornwall) and Plymouth.

50

CDŽSE SƼǟLjY Meaʣureɡ Wɛ ʛiʤiJatɏ ʏɔՕXȿɏ ʛiʎUɼʍiɪl pɼɸʙXʤiʝɚ ʢisk Methods to reduce pathogen transfers to watercourses essentially tackle aspects of source, mobilisation or delivery to the watercourse.

Perhaps the most eơective measures designed to reduce the sources of faecal and organic material are those that improve the management of manure by increasing slurry storage capacity, reduce inputs of rainwater to manure stores or switch to a conƤned composting system of storage.

By reducing the volume of contaminated material produced these measures enable farmers to restrict their application of manure to the land to dry periods, when the risk of washǦoơ is least. They also allow farmers to keep their yards free of contaminated material 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 a watercourse.

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

Location

Buơer Width (m)

Soil Texture

Slope (%)

Eƥcacy (% FIO reduction)

Atwill et al. (2002)

USA

3.1

Sandy loam

5Ǧ20

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

5Ǧ20

75Ǧ88

Reference

51

MICROBES & PARASITES

The Ƥnal type of intervention that can mitigate delivery of microbial contaminants to watercourse are riparian buơer strips and constructed wetlands that act to disconnect pollution pathways carrying material washed oơ the land surface.

The ability of these measures to disconnect runǦoơ has already been described in detail, but there have been a number of studies that have investigated their ability to reduce bacterial loads at Ƥeld and plot scale (summarised in table below).

COLƵ8R , ƼDŽSTE & ODƵ8R CƵǔƸƵǟǕLjS

COLOUR, TASTE & ODOUR

52

COLƵ8R,

ƼDŽSTE

&

ODƵ8R

There are a number of factors that may result in water exhibiting aberrations in its colour, taste or odour and which negatively aơect its quality and/or safety. On most occasions when colour, taste or odour problems do occur the impacts are primarily on the aesthetic quality of the water and therefore, with the resulting increase in the risk of water customer dissatisfaction, there is an increase in the intensity and cost of treatment required to remove it from the water.

Ferric (ironǦbased) compounds leach in to a stream (top) and heavily coloured water in the upper reaches of the River Dart (bottom).

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

Perhaps the best examples of this are metal ions which, in addition to causing aesthetic problems in the water, can have signiƤcant impacts on the ecological condition of rivers and streams.

SʝuUȪeɡ Է cɼOʝuɠ, WaVtɏ & oGʝuɠ cʝʛpʝunGɡ There are two main groups of soluble species that can cause colour, taste and odour problems, namely metal ions and soluble organic compounds (a component of dissolved organic carbon—DOC).

Soluble species

Sources

Impacts

Metal ions

Ǧ Aluminium

Natural release from underlying geology and biǦproduct of water treatment coagulation process.

Can cause discolouration of water. Evidence suggests there may be some health and ecological impacts of chronic expoǦ sure.

Ǧ Copper

Naturally occurring, but can be mobilised as a result of human activity.

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

Ǧ Iron

Naturally occurring, but can be mobilised as a result of human activity.

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

Ǧ Manganese

Naturally occurring, but can be mobilised as a result of human activity.

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

Ǧ Zinc

Naturally occurring, but can be mobilised as a result of human activity.

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

Organic compounds

Ǧ Geosmin

Produced by aerobically growing aquatic algae and microbes. Also produced by ƤlaǦ mentous actinomycete bacteria in soil.

Cause earthy taste and odour problems in drinking water that are very hard to remove without activated carbon Ƥltration.

Ǧ MethylǦIsoborneol (MIB)

Produced by aerobically growing aquatic algae and microbes. Also produced by ƤlaǦ mentous actinomycete bacteria in soil.

Cause earthy taste and odour problems in drinking water that are very hard to remove without activated carbon Ƥltration.

Ǧ Trihalomethanes (THMs)

Produced as a biǦproduct of chlorineǦ disinfection of drinking water containing organic material.

Growing evidence that THMs are carcinogenic. Very hard to remove without activated carbon Ƥltration.

Ǧ Humic substances

Produced by biodegradation of dead organic matter (e.g. peat, woodland, algae etc.)

Discolouration of water (yellow) that is very hard to remove without activated carbon Ƥltration.

Can reduce eƥciency of other treatment processes.

53

COLOUR, TASTE & ODOUR

These compounds (described in the table below) are often derived from natural sources in the environment, such as the underlying geology, or through the natural breakdown of organic material. However, in certain circumstances their levels can be artiƤcially elevated as an indirect result of human activities or as a direct biǦproduct of the water treatment process itself.

The drainage and overǦexploitation of peat bogs and other upland habitats with peatǦ based soils, is known to enhance the loss of dissolved organic carbon (DOC) to watercourses and to signiƤcantly increase water discolouration through contamination with colourǦcausing organic compounds such as humic acids (Worrall et al., 2007; Wallage et al., 2006; Armstrong et al., 2010).

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

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

In their Advisory Note 19 on, ‘Rivers and their catchments: potentially damaging physical impacts of commercial forestry’, Scottish Natural Heritage warn that ploughing and restructuring of drainage patterns may occur as part of ground preparation work prior to commercial tree planting. They also describe how drainage ditches are often aligned at right angles to the slope, which causes peak runǦoơ ƪows to arrive more rapidly in the receiving watercourse.

The eơect of this drainage, coupled with the increased availability of colourǦcausing compounds in the soil due to the decomposition of leaf litter and the degradation of the peat, could be the cause of the deteriorations in water quality now commonly observed in many watercourses and reservoirs in upland catchments.

Data showing large seasonal accumulations of geosmin (top) and manganese (bottom) in a small reservoir in the South West of England.

Other organic taste and odourǦcausing compounds that are generated in soil and decomposing organic material are geosmin and 2ǦMethylisoborneol (MIB). These compounds are also generated within many lakes and reservoirs as algal and macrophyte growth dies back at the ends of the growing season (see right).

Many colourǦcausing metals, such as iron, zinc and manganese, are released naturally from land with underlying geology where they occur and they can therefore be leached at quite signiƤcant levels into watercourses. This leaching can be signiƤcantly enhanced where geological disturbance has been caused through human activities such as mining.

COLOUR, TASTE & ODOUR

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

In addition to being catchmentǦderived, manganese ƪux in lakes or reservoirs can also occur as a result of seasonal stratiƤcation occurring in eutrophic waterbodies.

Manganese ions are mobilised into solution from lakeǦbed sediment when an hypoxic/ anoxic layer of water forms above it and, once solubilised, are then distributed throughout the waterbody when reǦmixing of the water column occurs in the autumn.

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

54

IʛpacWɡ Է cɼOʝuɠ, WaVtɏ & oGʝuɠ cʝnWʋʛʖnʋnWɡ On the health of aquatic ecosystems The ecological impacts of taste and odourǦcausing organic compounds (dissolved organic carbon) remain poorly understood, but their ecotoxicology has been investigated in a number of experimental systems and few toxic eơects have been demonstrated at the concentrations typically found in contaminated waterbodies.

In contrast, several metal ions have been shown to have an impact on the ecological health of aquatic ecosystems. As a result of these Ƥndings chromium, copper, iron and zinc are all listed as ‘speciƤc pollutants’ and have standards monitored as part of the ecological condition assessments undertaken for the Water Framework Directive classiƤcation process. The inclusion of manganese as a speciƤc pollutant in the next cycle of Water Framework Directive classiƤcation is currently being considered.

On the provision of drinking water The levels of colour, taste and odour compounds in raw water have a direct impact on the dose of coagulant required in its treatment at the water treatment works (indeed many works dose coagulant according to turbidity and colour levels in the raw water). If these compounds are not removed they can impinge on the aesthetic quality of the Ƥnal drinking water and cause the discolouration of drinking water infrastructure (for example manganese in treated water can stain sanitary ware).

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

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

CDŽSE SƼǟLjY Increasing levels of colour in the water from Fernworthy Reservoir on the eastern edge of Dartmoor represent a signiƤcant challenge for South West Water at the Tottiford water treatment works. The deterioration in the water quality in the reservoir was so severe that the Bovey Cross water works had to close because the treatment process could not cope with the raw water. The colourǦcausing compounds in Fernworthy Reservoir are primarily humic substances derived from the degradation of organic material in the peatǦlands and forested areas that surround this moorland reservoir (see land cover map; right). It is clear that water percolating through peat or forest leafǦlitter across the catchment is mobilising and transporting these colourǦcausing substances into the watercourses and drains that feed into the reservoir. This eơect is being signiƤcantly enhanced in areas where the peat has been damaged or degraded through drainage or intensive exploitation.

Humic colourǦcausing compounds in raw water can only be removed through the coagulation process at the works and so, if the colour levels in the water increase, it can have signiƤcant cost implications for the water company as the coagulant dose must also be increased. These organic compounds cause further problems at the works as they can be converted into disinfection byǦproducts (DBPs) when chlorine is used during water treatment.

Examination of South West Water data (left) shows that the level of colour in Fernworthy Reservoir cycles throughout the year, but also that the average level has signiƤcantly increased since 2004.

55

COLOUR, TASTE & ODOUR

CɼOʝuɠ ʖɚ FʑʢʜwɛԬʕɨ ReȿʑʢYʝʖɠ, 'ʑYʝɚ

Peatland restoration being undertaken by the Exmoor Mires Project (top) and stakeholders visit a restored mires site (bottom)

CɼOʝuɠ, WaVtɏ & oGʝuɠ ʛiʤiJaʤiʝɚ ȷeaʣureɡ Ultimately, the only way to completely remove the soluble organic compounds and metal ions that cause colour, taste and odour problems in raw water intended for treatment and supply as drinking water is to implement technological solutions, such as activated carbon Ƥlters, at the treatment works.

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

Having said this, however, there is increasing evidence that reǦwetting of peatǦlands and mires that have been degraded by drainage or overǦexploitation of peat can reduce the leaching of Dissolved Organic Carbon (DOC) compounds that cause colour, taste and odour contamination of raw water.

SpeciƤcally, several studies have demonstrated that the reǦwetting of mires and peatǦ lands, through the practice of drainǦblocking, can signiƤcantly reduce the loss of DOC and colourǦcausing compounds from land of this type (Wallage et al., 2006; Armstrong et al., 2010).

In their extensive UKǦwide survey of blocked and unblocked drains across 32 study sites and through the intensive monitoring of a peat drain system that has been blocked for 7 years, Armstrong et al. (2010) demonstrated that dissolved organic carbon concentrations and water discolouration were signiƤcantly (~28%) lower in blocked drains compared to unblocked drains.

Overall, whether the source of contamination is from mine works, forestry or peatland soils it is clear that it is the management of drainage and the hydrological regime of the land which may achieve the greatest eơect in mitigating the impacts of colour, taste and odourǦcausing contaminants.

CDŽSE SƼǟLjY Tȱɏ SXVWʋʖnɪɬȵɏ CaWɭʕȷʑnɢ MʋnaȰʑȷʑnɢ PUoʔUʋʛȷɏ (SCɈǔP) The Sustainable Catchment Management Programme (SCaMP), has been developed by United Utilities in association with the Royal Society for the Protection of Birds (RSPB).

The programme aims to apply an integrated approach to catchment management across all of the 56,385 hectares of land United Utilities own in the North West, which they hold to protect the quality of water entering the reservoirs.

Through the delivery of SCaMP United Utilities is recognised within the UK water industry as being at the forefront of water companyǦfunded catchment management scheme that are aiming to secure multiple beneƤts at a landscape scale.

Over the last 30 years there has been a substantial increase in the levels of colour in the water sources prior to treatment from many 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, expensive capital solutions are often required at a water works which result in signiƤcant increases in annual operational costs.

COLOUR, TASTE & ODOUR

The aims of the SCaMP initiative are to help; (1) protect and improve water quality, (2) reduce the rate of increase in raw water colour which will reduce future revenue costs, (3) reduce or delay the need for future capital investment for additional water treatment, (4) deliver government targets for SSSIs, (5) ensure a sustainable future for the company's agricultural tenants, (6) enhance and protect the natural environment, and (7) help these moorland habitats to become more resilient to long term climate change.

Monitoring at a subǦcatchment level in SCaMP delivery areas indicates that there is a statistical ‘tipping point’ two years after intervention. This has been found in similar short term studies and it is thought that reǦwetting dried peat initially releases more carbon in the form of colour before the natural biochemical processes begin to reǦestablish. At present several subǦcatchments are indicating a slight, but statistically signiƤcant, decrease in colour over time and one site has seen a signiƤcant 45% reduction in stream ƪow turbidity since restoration.

For more information visit—corporate.unitedutilities.com/scampǦindex.aspx 56

DŽǜSNJǜƻǏǕ* ƮǔPƺ2VƩMNJNǝS ǏN WATER QUDŽLIǝ Y

57

AǜSNJǜƻǏǕ* IǔPƺ2VƩMNJNǝS The principal, overǦarching aim of any catchment management work is to improve the water quality in our freshwater ecosystems and to make a signiƤcant contribution to their attainment of good ecological status in accordance with requirements of the EU Water Framework Directive. It is therefore vital that suƥcient evidence is collected to provide an objective and robust assessment of the improvements delivered.

Ultimately, we must be able to justify that the money spent and the interventions delivered across the landscape have delivered signiƤcant improvements in water quality (and have therefore made signiƤcant contributions to the delivery of good ecological status of river catchments) and have generated signiƤcant secondary Ƥnancial, ecological and social beneƤts.

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

QuantiƤcation of intervention delivery. Gathering precise and detailed evidence of what has been delivered, where and how it was delivered, what it cost and, perhaps most importantly, what the intended outcome was for each measure.

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

Modelling to predict environmental outcomes. Use of the most advanced modelling techniques which can be used to estimate the improvements in water quality that have been achieved.

Assessment of secondary outcomes. There are a number of monitoring and modelling approaches that can be used to assess how a catchment management programme has enhanced the provision of other ecosystem services across a catchment and to quantify the economic beneƤts to those engaged in the process.

CDŽSE SƼǟLjY Tȱɏ 'EFƺA 'ʑPʝnVʤUaʤiʝɚ TeVɢ CaWɭʕȷʑnWɡ ('TC) As part of a national drive to gather evidence that catchment management can have a signiƤcant impact on raw water quality DEFRA are currently funding a £5 million Demonstration Test Catchment (DTC) Project across three catchments: the Hampshire Avon, the Wensum and the Eden. The aim of DTC Projects is to evaluate the eơectiveness of onǦfarm measures to improve water quality when their delivery is scaledǦup to a realǦlife whole subǦcatchment 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. The DTC consortium is undertaking a detailed monitoring programme before and after the a comprehensive farm investment and advice programme being delivered across the catchment.

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

In addition to this chemical monitoring programme, extensive biological monitoring has also been undertaken in the catchment, including the assessment of macroǦinvertebrates, benthic algae (diatoms), macrophytes and Ƥsh.

The baseline data for Caudworthy Water has been collected over an 18 month period and Westcountry Rivers Trust have approached all twentyǦfour farmers in the Caudworthy Water subǦcatchment. To date, over £450,000 has been invested in around £700,000 worth of capital investments with Best Management Practices ensured through the application of a Restrictive Deed on 19 of these farms.

Following the implementation of the Best Management Practices in 2012Ǧ13, the eơects on water quality will then be monitored over 2013Ǧ15.

58

CDŽSE SƼǟLjY Tȱɏ E[tʑndeɍ Eʩpɛԭ Cȹeɑ£ʎȲʑnɢ Modɰl (EȉM+) The Extended Nutrient Export Coeƥcient Model (ECM+) has been developed by the University of East Anglia under the Rural Economy and Land Use (RELU) Programme and partǦfunded by the Westcountry Rivers Trust. This model has been reviewed by scientiƤc peers and the DEFRA Water Policy Group and is widely expected to become one of the primary methods for rural land management planning through stakeholder participation in the future.

ECM+ has been developed to predict the eơects implementation of Best Management Practices (BMP’s) (Cuttle et al. 2007) will have on sediment, faecal indicator organisms (FIOs), phosphorus and nitrogen inputs into watercourses.

Put simply, the model uses export coeƥcients for diơerent landǦuse types to calculate exports of these pollutants based on the following input data:

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

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

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

Population not served by STWs—indicative of septic tank numbers Road and track density Rainfall and hydrological data combined with information on inǦstream processing of pollutants

Location and area of lakes and reservoirs with modelled impact on pollutant load at outƪow

Farming practices: current uptake of Best Management Practices and eơectiveness in reducing pollutant export What makes the ECM+ model such a powerful tool is that it is constructed with the participation of farmers, water company representatives and other stakeholders in the catchment and this allows all of the input data to be ‘groundǦ truthed’ before it is added into the model. In addition, the model is calibrated at the subǦcatchment level with realǦworld, inǦstream measurements 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 a number of scenarios with the stakeholders (which can include diơerent blends of both Best Management Practices on farms and improved sewage treatment measures) and observe their eơects on the export of pollutants to the watercourse.

ECM+ in Action The River Tamar is a key raw water source for South West Water and has been the subject of considerable investment in catchment management interventions through schemes such as Upstream Thinking and Catchment Sensitive Farming.

The Caudworthy Water subǦcatchment of the River Ottery in the Tamar catchment is also a satellite study site for the DEFRA Demonstration Test Catchment (DTC) project on the Hampshire Avon.

In light of its importance as a drinking water catchment and for the Water Framework Directive (the Crownhill WTWs catchment is comprised of 45 WFD waterbodies) the ECM+ model has been built for the River Tamar catchment above its tidal limit at Gunnislake through a participatory development process.

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

59

Extended Export Coeƥcient Model (ECM+)...continued….

This case study summarises the ECM+ predicted export of nitrate and phosphate from the Tamar catchment under four diơerent management scenarios, involving diơerent levels of implementation of the top 35 (most commonly used) Best Management 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 subǦcatchment 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 stripping eƥciency at all Sewage Treatment Works.

The model outputs show the predicted average concentration of each pollutant against speciƤc standards. For phosphate, the background matches the classiƤcation used for the EU Water 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 preǦabstraction standard for drinking water is deƤned by the dark blue vertical line on the far right of the nitrogen export graphs below (equating to 11.3 mg/l). The bright 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: Baseline The outputs from the ECM+ model (right) indicate that the Caudworthy subǦcatchment under the current ‘businessǦasǦ usual’ scenario (Scenario 1) is likely to have an average phosphorous export load corresponding to moderate/poor ecological status.

At Gunnislake Bridge the phosphate levels are likely to be moderate.

Below the Caudworthy outƪow and Gunnislake Bridge the nitrogen levels are likely to be compliant with the drinking water standard, but exceed the ecological standard in both locations.

Scenario 2: 100% BMP uptake on the Caudworthy In Scenario 2 (not shown), the model predicts that average water quality in the Caudworthy subǦcatchment will improve to better than good ecological status for phosphate and will be compliant with the more stringent ecological standard for nitrogen. The eơect of this level of action in the Caudworthy is also passed on to Gunnislake, but the improvements are masked 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 Water outƪow and Gunnislake Bridge both improve signiƤcantly with nitrogen levels at both sample sites predicted to be compliant with 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% chance that the water quality at the Caudworthy outƪow and Gunnislake Bridge would both meet water framework directive standards for phosphorous and that nitrogen levels would be compliant with stringent ecological standards.

ECM+ predicts signiƤcant 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 successful stakeholder engagement, including private, public and third sector organisations and landowners.

60

CDŽSE SƼǟLjY FʋʢPVcʝȼʑɠ ʝɚ ʃȱɏ Hʋʛpsʕʖrɏ AYʝɚ The FARM SCale Optimisation of Pollutant Emission Reductions (FARMSCOPER) model is a decision support tool that can be used to assess diơuse agricultural pollutant loads on a farm and quantify the impacts of farm pollution control options on these pollutants.

FARMSCOPER allows for the creation of unique farming systems, based on combinations of livestock, cropping and manure management practices. The pollutant losses and impacts of mitigation can then be assessed for these farming systems.

The eơect of a potential mitigation methods are expressed as a percentage reduction in the pollutant loss from speciƤc sources, areas or pathways.

The tool utilises a number of existing models including:

Phosphorus and Sediment Yield Characterisation in Catchments (PSYCHIC) National Environment Agricultural PollutionǦNitrate (NEAPǦN) National Ammonia Reduction Strategy Evaluation System (NARSES) MANure Nitrogen Evaluation Routine (MANNER) IPPC methodology for methane and nitrous oxide.

The eơectiveness of mitigation methods are characterised as a percentage reduction against the pollutant loss from a set of loss coordinates. The eơectiveness values were based on a number of existing literature reviews, Ƥeld data and expert judgement and are assumed to incorporate any eƥciencies of implementation.

The eơectiveness values for mitigation methods were allowed to take negative values, which can represent ‘pollution swapping’, where a reduction in one pollutant is associated with an increase in another.

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

The Hampshire Avon Study The Hampshire Avon is a lowland system situated on the southern coast of England. It is a predominantly rural catchment with approximately 75% of land used for agriculture. Parts of the Avon suơer from ‘chalk stream malaise’ due to nutrient and sedimentation issues that are thought to primarily originate from diơuse agricultural pollution. Over 50% of the waterbodies in the catchment do not achieve good ecological status under the Water Framework Directive.

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

trekker308

Spatial datasets and the Agricultural Census returns for the River Avon in 2009 were used to develop a collection of farm types characteristic of the Hampshire Avon and reƪective of landuse patterns, physical landscape characteristics and farm management 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 52 horticultural farms (less than 1% of land area) in the Avon catchment. The remaining land area comprised small numbers of general cropping, pig, poultry or ‘other’ representative farm types.

FARMSCOPER was then used to test three diơerent 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 no mitigation measures Scenario 2: Current pollutant emissions based on an estimate of the existing level of mitigation measures implemented

Scenario 3: Maximum reductions through implementation of all measures in the Defra User Guide (Newell et al. 2011) 61

FARMCOPER on the Hampshire Avon...continued….

Results FARMSCOPER predicts baseline pollutant loadings in kg per hectare per year (kg haǦ1 yrǦ1) (see table). Under scenario 1, the baseline levels of pollutant emissions if no mitigation measure were in place, it estimated that cereal farms would contribute about 55% of nitrate, 38% of phosphorous, 67% of sediment and 50% of nitrous oxide. Mixed farms were estimated 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. These predictions were compared with monitored data for pollutant loads in the Avon and were considered acceptable.

Farm Type

Nitrate (NO3)

Phosphorous

Sediment

Ammonia (NH3)

Methane (CH4)

Nitrous oxide (N2O) 7

Cereals

38

0.2

159

7

0

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

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 mitigation measures implemented, the estimated percentage reductions in pollutant emissions ranged from 0 to 15.2%.

Farm Type

Nitrate (NO3)

Phosphorous

Sediment

Ammonia (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%

Phosphorous

Sediment

Ammonia (NH3)

Methane (CH4)

Nitrous oxide (N2O)

Under scenario 3, which is the delivery of the maximum reductions through implementation of all mitigation measures listed in the Defra Inventory of Methods to Control Diơuse Water Pollution (Newell et al. 2011), the estimated percentage reductions in emissions for speciƤc pollutants were much greater, ranging from 0 to 70.8%.

Farm Type

Nitrate (NO3)

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 haǦ1 yrǦ1) resulting from scenarios 2 and 3 to be compared (see below).

Farm Type

Nitrate (NO3)

Phosphorous

Sediment

Ammonia (NH3)

Methane (CH4)

Nitrous oxide (N2O) 6.2%

Cereals

4.0%

6.0%

7.8%

9.0%

0.0%

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%

Conclusion FARMSCOPER estimated that current levels of mitigation measure implementation have reduced total pollutant loads by between 3 and 10%, as compared to a scenario where no mitigation measures were in place. It also predicted that, should there be signiƤcant uptake of the full range of mitigation measures, pollutant loads could be reduced further by signiƤcant 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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SecʝnGʋʢɨ ȩʑȸɏ£Wɡ Է caWɭʕȷʑnɢ PʋnaȰʑȷʑnɢ It is widely accepted that the delivery of catchment management interventions will produce a wide array of ancillary beneƤts that could make considerable contributions to improving the ecological condition of rivers and towards other economic, environmental or nature conservation targets.

Secondary environmental beneƤts In addition to determining the primary beneƤt obtained through catchment management interventions, it is also important for any secondary environmental beneƤts achieved to be recorded and quantiƤed.

This can be undertaken using a number of survey, monitoring and modelling approaches that assess how an intervention can enhance the provision of other ecosystem services across a catchment and to quantify the economic gains achieved by all of the groups engaged in the process.

Perhaps the most common example of this occurring is where interventions, such as wetland creation or restoration, which have been designed and targeted to enhance the regulation of water quality also play a key role in the regulation of water quantity (high and low ƪows). It is clear that these measures, if targeted into multifunctional areas of land that regulate several diơerent ecosystem services, are capable of enhancing the provision of several of them.

In addition, considerable research is also being undertaken to asses the ability of catchment management interventions to restore ecosystem health, deliver increased biodiversity and for them to therefore have signiƤcant conservation value. In one such study, undertaken by Jobin et al (2003) in Canada, it has been demonstrated that the creation of riparian buơer strips (especially wooded ones) can signiƤcantly increase the overall species richness and insectivorous bird abundance across a catchment.

Many of the onǦfarm measures described in this review have also been shown to reduce the emission of greenhouse gases from agricultural land and there is growing evidence that many may act to increase their sequestration. Careful targeting of catchment management measures to land areas with the greatest carbon sequestration potential will optimise the levels of sequestration achieved.

A brown trout from a healthy river

At a more strategic level, several groups and organisations (such as Durham Wildlife Trust, the Westcountry Rivers Trust, and many others) have developed methodologies for the mapping of land which contributes to the provision of ecosystem services. When combined together, these studies reveal that there are many multiǦfunctional areas that play a key role in the delivery of several ecosystem services.

These ecosystem services mapping exercises allow us to identify sections of the catchment where these multifunctional, ecosystem servicesǦproviding areas may come into direct conƪict, and therefore be compromised by, other human activities, such as intensive agriculture or urban development.

This soǦcalled ‘ecosystem services’ approach allows us to identify where catchment management or policy level interventions designed to improve the provision of one ecosystem service (e.g. water quality) may also yield concurrent improvements in the provision of other ecosystem services. Ultimately, this approach allows interventions to be delivered in a targeted, integrated and balanced way that delivers the greatest environmental improvement for the resources available.

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Assessment of Ƥnancial costs and beneƤts For the full beneƤt of catchment management interventions to be assessed, it is also important for all of the parties involved (funders, deliverers, beneƤciaries, landowners) to have a clear understanding of the Ƥnancial costs and beneƤts of the proposed change. For many interventions, a clear and detailed understanding of their cost of delivery has already been gained and, as we have described previously, the evidence for their environmental beneƤt continues to be gathered.

The key link that will need to be established, once this evidence is in place, is how the environmental beneƤts achieved can be translated into Ƥnancial beneƤts for the funder, the beneƤciaries of the ecosystem service or the land managers who have implemented the intervention (e.g. as the result of increased eƥciency or reduced costs incurred).

This information will then allow the costǦbeneƤt of catchment management interventions to be explored in more detail. At present, the robust extrapolation of the costǦbeneƤt ratios calculated up to the subǦcatchment or catchment scale remains a signiƤcant challenge that will require careful consideration and further research.

CDŽSE SƼǟLjY PʋʪȷʑnWɡ fʝɠ EcoʣyVtʑm SʑʢviȪeɡ (PNJS) Payments for Ecosystem Services (PES) schemes are marketǦbased instruments that connect ’sellers’ of ecosystem services with ‘buyers’. The term Payments for Ecosystem Services is often used to describe a variety of schemes in which the beneƤciaries of ecosystem services provide payment to the stewards of those services. Payments for Ecosystem Services schemes include those that involve a continuing series of payments to land or other natural resource managers in return for a guaranteed or anticipated ƪow of ecosystem services.

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

A Payments for Ecosystem Services scheme can be deƤned as a voluntary transaction where (1) a wellǦdeƤned ecosystem service (or a landǦuse likely to secure that service) is being ‘bought’ by (2) an ecosystem service buyer (minimum of one) from (3) an ecosystem service seller (minimum of one) if, and only if, (4) the ecosystem service provider secures ecosystem service provision (conditionality).

An example of a PES scheme: Upstream Thinking Drinking water is a vital ecosystem service that we derive from our river catchments and there is signiƤcant scope for water 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 55Ǧ60 million litres of water each day and it is anticipated that over the next 20 years the demand for water in Plymouth will increase steadily towards 100 million litres a day. In addition to this increased demand for water, there is evidence that declining water quality in the river sources used to supply the Crownhill works could concurrently increase the costs and risks associated with 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 catchment management on behalf of their customers in an attempt to avoid incurring the extra costs and risks associated with treating low quality raw water at the works. If the average cost of treating water at Crownhill is increased by £5 per million litres treated (~10%) due to poor raw water quality then the removal of this pressure could save over £2 million on treatment costs over the next 20 years (at a treatment volume of 60 million litres a day).

Under the current situation, where land is managed exclusively for agricultural production, only the private proƤts from this activity are realised. By identifying where another ecosystem service, such as improved water quality, may be provided and by oơering either a minimum payment to cover proƤt forgone or a maximum possible payment based on the overall value to society, the buyer can incentivise the seller to change, or even switch, their practice and therefore deliver the improvements in the ecosystem service they require.

64

G2VEǛƴDŽNǨE & STƺATNJGIC ǙLDŽǕƴǏǕ*

65

Overall (top) and Ƥsh (bottom) status of waterbodies in the Tamar catchment under the Water Framework Directive classiƤcation system.

*2VEǛƴDŽNǨE & PLDŽǕƴǏǕ* Tȱɏ EC :atʑɠ FUʋȷʑwʝʁk 'ʖrecʤʖɃɏ 200 Perhaps the greatest driver for catchment management is the requirement for the condition of UK river waterbodies to meet the quality standards set out in the European Commission Water Framework Directive 2000 (WFD, 2000). The WFD assessment process, which applies to lakes, rivers, transitional and coastal waters, artiƤcial and heavily modiƤed waterbodies, and groundwater, has set more rigorous and higher evaluation standards for the quality of our aquatic ecosystems.

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

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

In addition to protecting and improving the ecological condition of aquatic ecosystems, the Water 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 eơects of ƪoods and droughts

Tȱɏ caWɭʕȷʑnɢ pɈԯȸʑUsʕʖɞ ʋpʠUoaɭh In recent years it has been increasingly recognised that enhancing the delivery of ecosystem services through better catchment management should not only be the responsibility of the public sector, but also the private and third sectors.

Alongside this movement towards shared responsibility, there is also now a growing body of evidence that far greater environmental improvements can be achieved if all of the groups actively involved in regulation, land management, scientiƤc research or wildlife conservation in a catchment area are drawn together with landowners and other interest groups to form a catchment management partnership.

A number of research projects have now been able to demonstrate that an empowered catchment area partnership comprised of diverse stakeholders and technical specialists from in and around a catchment, can be responsible for coordinating the planning, funding and delivery of good ecological health for that river and its catchment. They have also shown us that an integrated stakeholderǦdriven assessment of a catchment will we be enable us to develop a comprehensive understanding of the challenges we face and, following this, to develop a strategic, targeted, balanced and therefore costǦ eơective catchment management intervention plan.

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CDŽSE SƼǟLjY RuUɪl Ecʝnʝʛɨ & /ʋnɍ 8ȿɏ (RNJL8) PUoʔUʋʛȷɏ The interdisciplinary RELU Programme, funded between 2004 and 2011, had the aim of harnessing the sciences to help and promote sustainable rural development and advance understanding of the challenges caused by this change today and in the future. Research was undertaken to inform policy and practice with choices on how to manage the countryside and rural economies.

The Ƥndings of several RELU projects highlighted the need for more sustained and twoǦway communication with stakeholders about land management. The researchers have demonstrated that new ‘knowledgeǦbases’ can be established that combine local knowledge with external expertise.

The research has also identiƤed a number of techniques that enable stakeholders, who may start with diơerent views and levels of understanding, to redeƤne the issues collectively in a way that can help them Ƥnd innovative solutions with multiple beneƤts.

Perhaps the best example of this work is the ESRCǦfunded RELU study, led by Laurie Smith from SOAS at the University of London, which developed the concept of a ‘catchment area partnership’ (CAP) and ‘catchment area delivery organisations’ (CADO) approach for the delivery of catchment management in England and Wales.

Piloted in the Tamar and Thurne catchments, the project drew on the scientiƤc and social accomplishments of several innovative catchment programmes in the USA and other European countries and examined how they could be adapted for use in the UK. The SOAS project established a clear catchment management ‘roadmap’ (above) on how to: create a catchment partnership, integrate scientiƤc investigation with policy, establish governance and legal provisions; foster decisionǦ making and implementation at the appropriate governance level to resolve conƪicts; and to share best practice.

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

Tȱɏ ‘CaWɭʕȷʑnɢ-Baȿeɍ ApʠUoaɭh’ (CɈƥA) In response to this increased understanding of the potential beneƤts of participatory catchment planning, undertaken with local stakeholders and knowledge providers, in 2011 the Environment Minister Richard Benyon MP announced that the UK Government was committed to adopting a more ‘catchmentǦbased approach’ to sharing information, working together and coordinating eơorts to protect England’s water environment.

Following their announcement, DEFRA began working with the Environment Agency to explore improved ways of engaging with people and organisations that could make a real diơerence to the health of our rivers, lakes and streams.

In the summer of 2011, they launched a new initiative to test the catchment partnership approach in ten 'pilot' catchments. Alongside these ten Environment AgencyǦled pilots they also established Ƥfteen further pilot catchments that would be hosted by other organisations.

The outputs of the DEFRA Catchment Pilot Projects, which are now presented on the Catchment Change Management Hub website (ccmhub.net), reveal that the new partnerships created in many catchments were able to generate ambitious and comprehensive 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 their policy framework for the rollǦout of the CatchmentǦBased Approach (CaBA) to all of the ~80 catchments in England and catchment hosts will be selected in autumn 2013.

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The DEFRA CatchmentǦBased Approach Policy Framework, May 2013.

CDŽSE SƼǟLjY CaWɭʕȷʑnɢ-Baȿeɍ ApʠUoaɭh (CɈƥA) PɵlԦɡ To develop an understanding of how the catchmentǦbased approach could work in practice, a series of catchmentǦlevel partnerships were developed through a pilot phase (May 2011 to December 2012). Ten of these partnerships were hosted by the Environment Agency (EA) and 15 were led by a range of stakeholders such as Rivers Trusts, Groundwork, water companies and community groups. A group of 41 wider catchment initiatives were also established that were not part of the formal evaluation.

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

The Tamar Plan The Tamar Catchment Plan adopted a stakeholderǦled ‘ecosystem services’ approach to catchment planning. This has involved the host organisation working with stakeholders to identify areas within the catchment which play, or have the potential to play, a particularly important role in the delivery of clean water and a range of other beneƤts (services) to society.

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

Saving Eden The Eden Pilot Project, hosted by Eden Rivers Trust within the Eden and Esk management catchment encouraged greater levels of participation including increased levels of engagement with ‘diƥcult to reach’ groups and facilitation of knowledge exchange between stakeholders. The pilot project produced a plan called ‘Saving Eden’, which summarises the current health and the necessary actions required to deliver Good Ecological Status in the Eden catchment.

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

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

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

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

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

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

Our vision is:Ǧ

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 the services it provides – Payments for Ecosystem Services.

Educate and reconnect society with the natural environment.

To base our work on good scientiƤc research.

To Ƥnd out more out more about the Westcountry Rivers Trust please visit our website at www.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 Trust and Managing Director of Tamar Consulting. He is an experienced farm and land management advisor and has led Defra funded projects investigating Water Framework Directive Metrics and implementation of catchment management plans to inform good status.

Email: dylan@wrt.org.uk Dr Laurence Couldrick Head of Catchment Management Dr Laurence Couldrick is the Head of Catchment Management at the Westcountry Rivers Trust and Project manager for the Interreg funded WATER Project on the Payments 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 using spatial techniques to inform conservation strategy development and catchment management. He provides data, mapping & modelling support for all Trust projects and coordinates and manages a number of largeǦscale monitoring programmes currently being undertaken by the Trust.

Email: nick@wrt.org.uk Lucy Morris Data to Information Oƥcer Lucy is an ecologist and data analyst specialising in the communication of the Trust’s scientiƤc outputs to a wide variety of audiences. Lucy collates and assesses data and evidence before preparing press releases, articles and technical documents for publication in a variety of media types, including traditional print media, Ƥlm/TV, online/ websites and new media such as social networking sites.

Email: lucy@wrt.org.uk Hazel Kendall Upstream Thinking Project Oƥcer Working with Upstream Thinking partners to collate information and data collection for reporting, Hazel will combine this role with bioǦmonitoring undertaken as part of the proof of concept study supporting the physical works of the initiative, using a range of sampling techniques and Biotic Indices.

Email: hazel@wrt.org.uk

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The Upstream Thinking Project is South West Water's ƪagship programme of environmental improvements aimed at improving water quality in river catchments in order to reduce water treatment costs. Run in collaboration with a group of regional conservation charities, including the Westcountry Rivers Trust and the Wildlife Trusts of Devon and Cornwall, it is one of the Ƥrst programmes in the UK to look at all the issues which can inƪuence water quality and quantity across entire catchments.

The principal, overǦarching aim of any catchment management work is to improve the water quality in our freshwater ecosystems and to make a signiƤcant contribution to their attainment of good ecological status in accordance with requirements of the EU Water Framework Directive. It is therefore vital that suƥcient evidence is collected to provide an objective 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 catchment management interventions can realise genuine improvements in water quality. To support the evidence collected, we have also summarised a number of case studies which demonstrate catchment management in action.

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