UU Catchment Management Report: River Dee

Photo: Flickr, Reflection of a Tree (River Dee) by Dunnock_D (CC BY-NC 2.0)

River Dee Catchment Using Data and Evidence to Target Water Quality Measures

The River Dee Catchment Management Review Water is essential to life; we need it every day to drink, wash and grow food. It sustains all of the differing landscapes that surround us. We all have an impact on the quality of our water, whether it is at home checking that drains are correctly connected or using garden products wisely, industrial activity from businesses of all sizes, managing the land for food and energy production or providing areas to play and relax, including golf courses, sports fields and parks. We need to work together as communities, along with governments and regulators, to protect this valuable resource.

Sustainable Catchment Management United Utilities’ Sustainable Catchment Management Programme (SCaMP) is protecting and improving the quality of waterin rivers and aquifers across the North West of England and cross-border Wales to reduce water treatment costs.

River catchment management tackles the source of pollutants rather than focusing on end-of-pipe water treatment, which is highly chemical- and energy-intensive. United Utilities are committed to working in partnership with the Environment Agency, Natural Resources Wales and wider partners, including Rivers Trusts, Wildlife Trusts, Farming Unions and local colleges, to deliver the broad range of social and environmental benefits that are generated from a cleaner water environment.

These benefits include:  Reduced customer water bills  Cleaner beaches  Reduced carbon emissions  Improved habitat for wildlife  Increased habitat resilience (for example to climatic changes)  Reduced surface runoff, contributing to flood alleviation  Supporting local communities  Supporting farm business viability Understanding the interactions between the land and the United Utilities Water Supply Area and Surface Water Safeguard Zones water is crucial to the successful management of essential water resources. Catchment management investigates these interactions and aims to combat or mitigate the activities in the river catchment that are detrimental to the sustainability of water quality and biodiversity, as well as reducing flood risk.

The River Dee Catchment Review The River Dee is a vitally important natural resource for communities in North Wales and North West England, supporting a rich environment for wildlife, while also providing a valuable source for drinking water extraction. The river flows are controlled by Natural Resources Wales through programmed releases from the main balancing reservoirs; Lake Bala, Lake Celyn and Lake Brenig. The Dee Regulation Scheme balances the interests of abstractions, fisheries, biodiversity, recreational activities and flood risk management. Furthermore, the releases reduce the ingress of saline water above Chester Weir during high tides.

In 1999, the River Dee became the UK’s first Water Protection Zone following an industrial pollution incident, where nearly 3 million people received drinking water that tasted of TCP. Now, unique legal requirements exist for companies that hold >50 litres of specific chemicals and are based within the Water Protection Zone, which includes Bala, Llangollen, Bangor-on-Dee, Wrexham, Mold and Chester. Since the designation came into effect, there has been a marked reduction in industrial pollution incidents. However, in recent years the amount of agricultural pesticides detected in the River Dee has risen, causing pesticide risk management to be taken very seriously and monitored closely by local water regulators. The majority of catchment management activities that are currently being planned or implemented are focused on pesticide management and surface water runoff issues.

This review describes the wide range of data and evidence gathered for the River Dee that has helped United Utilities to develop and target their catchment management actions. It includes information on hydrology, land use and agriculture, as well as risk-prediction models and water quality monitoring results. In the final section, the review summarises the actions on the ground that have been carried out up to the present time.

This document was produced by Westcountry Rivers Trust for United Utilities and published in June 2017.

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Contents This review has been divided into six sections (outlined below), designed to guide the reader through the range of data and evidence used to assess water quality characteristics and issues in the Dee river catchment. It describes how priority areas have been identified and how measures have been targeted on the ground. The datasets used to create the maps and graphics are derived from a variety of sources, which are acknowledged at the bottom of each page.

River Dee Catchment Overview (P4-5) This chapter gives an overview of the hydrological characteristics of the catchment, including abstraction regimes, flow rates and rainfall. It also describes the distribution of land use types and agricultural land grade across the river catchment.

Pollution Sources and Risks (P6-7) A range of pollution sources are present across the river catchment, each with varying degrees of impact on water quality. This chapter highlights agricultural, urban and domestic pollution sources, and the variables that influence pollution risk.

Using Models to Identify Risk (P8-9) This chapter investigates the use of computer models to identify sites that are at a high risk of pollution generation and/or transport.

Specifically, it looks at Scimap for sediment erosion modelling and the UKWIR pesticide risk tool for pesticide modelling.

Monitoring to Target Action (P1-12) This chapter describes the different monitoring methods used to assess water quality in the river catchment. As well as routine sampling carried out by regulatory bodies and water companies, a new passive sampling technique has also been utilised.

Data and Evidence Summary (P13) The data and evidence described in this report were examined and discussed by a variety of local stakeholders and subsequently the river sub-catchments were prioritised according to the risk they pose for pesticide pollution.

Action to Improve Water Quality (P14-15) This chapter highlights the actions carried out on the ground by local organisations to improve land practices and ultimately, river water quality. Data and evidence helped to target interventions by taking a strategic approach to catchment management.

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River Dee Catchment: Water The River Dee flows from the highlands of Snowdonia, through a number of settlements including Llangollen and Chester, before joining the Irish Sea. The river and its tributaries pass through several unitary authorities, including Gwynedd, Conwy, Denbighshire, Wrexham, Flintshire, Shropshire and Cheshire. Raw water is abstracted from a number of sites across the River Dee catchment and is treated to provide drinking water to a population of almost three million. It is therefore a highly important resource and is managed and monitored closely by local water authorities to ensure that high quality standards are maintained. Natural Resources Wales is responsible for regulating and responding to incidents on the River Dee in Wales and the Environment Agency in England.

The upland tributaries of the Dee tend to be flashy in nature with an average annual rainfall of ~2,000mm, compared with ~700mm in the lowlands. The lowland reaches tend to have slower flow rates and a greater groundwater contribution than the upper catchment. The natural flow of the River Dee during summer months would usually be insufficient to sustain any significant abstractions.

To overcome this problem, a series of reservoirs have been constructed Abstraction: Huntington & to store the excess water available in the winter time and release Heronbridge it back into the River Dee during the drier months.

Use: Public Water Supply Abstraction: River Dee at Poulton Use: Public Water Supply

Owner: United Utilities Annual limit: ~250,000 ML

Owner: Welsh Water

Abstraction: River Dee

Annual limit: ~9,000 ML

Use: Public Water Supply Owner: Dee Valley Water Annual limit: ~15,000 ML

Abstraction: Alwen Reservoir Intake

Abstraction: River Dee at Bangor-on-Dee

Use: Public Water Supply & Transfers

Use: Public Water Supply Owner: Dee Valley Water Annual limit: ~15,000 ML

Owner: Welsh Water Annual limit: ~18,000 ML

River Dee catchment boundary (upstream of Chester Weir) Area = 1,802km²

Hydrology & Water Quality Rainfall and flow regimes are important factors when considering water quality and pesticide risk, as they affect mobilisation of pollutants and dilution levels. The Dee Regulation Scheme, operated by Natural Resources Wales, ensures that water is released from reservoirs when flows fall below 8.1m³/s at Manley Hall and 4.2m³/s at Chester Weir. The Dee Regulation scheme ensures that pollutants entering the river in summer are subject to greater dilution than would be the case if there was no regulation. However, the converse is true in storm events in winter where flow regulation can reduce the flows in the river. The lowland rivers have a higher proportion of field drains and drainage ditches, resulting in potentially greater connectivity between pollutants and water courses.

Average Annual Rainfall Met Office data shows the average annual rainfall values across the Dee river catchment

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure and topography datasets from Strategi® and Boundary-LineTM, OS Terrain®50, Environment Agency Detailed River Network v3, Centre for Ecology & Hydrology NFRA Daily Flow Data (2010 & 2012), Environment Agency Abstraction Licenses (2015), Met Office Average Rainfall 5km grid (1961-1990)

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River Dee Catchment: Land Use Land cover type and practice have a strong influence on the degree of pollutants found in surface waterbodies. The physical characteristics of the land (such as surface roughness, soil type and slope) affect how water and pollutants move across the landscape and enter watercourses. Land management practices can not only affect the amount of pollutants that are generated but can also greatly influence the pathway along which they travel.

There are a wide range of pollutants generated from different land use types and the severity of their impact on drinking water quality varies greatly. Pesticides are of particular concern as they can be expensive and difficult to remove at treatment works. Land cover data can be used to identify high risk areas across the catchment and to predict where different types of pesticides are likely to occur.

Land Cover Class by Sub-Catchment This chart shows the percentage of different land cover classes for each subcatchment

Aldford Catchment Alwen Alyn Ceiriog

Urban Areas Large urban areas such as Llangollen and Wrexham are potentially substantial exporters of domestic pesticides, for example, the use of herbicides to clear weeds from patios and driveways

Clywedog Dee Lower Dee Middle Dee Upper Emral Brook Pulford Brook

Arable Land Much of the lowlands comprise of intensive agriculture. 40% of the Aldford sub-catchment is arable and 50% is improved grassland. There is a high risk of metaldehyde use in these areas to control slugs

Shell Brook Upper Alyn Worthenbury & Wych 0%

20%

40%

60%

80%

100%

Woodland 20% of the Upper Alyn catchment is broadleaved or coniferous woodland.

This could help to buffer the impact of pesticides if situated appropriately

Improved Grassland 75% of the Emral Brook catchment is improved grassland, meaning MCPA is a likely risk

Upland Grassland Less than 3% of the Upper Dee subcatchment is arable, while 45% is either improved or acid grassland.

Therefore, metaldehyde risk should be low, but MCPA is likely to be used for grassland rush control

Agricultural Land Classification Agricultural land grade gives a good indication of where intensive agriculture, and subsequently pesticide use, is likely to occur. In the Dee catchment the western half is primarily classed as ‘poor’ or ‘very poor’, while the eastern areas are largely ‘good’ to ‘very good’ land grade.

Agricultural Land Classification Datasets provided by Natural Resources Wales and Natural England show agricultural land grades across the catchment

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from Strategi® and Boundary-LineTM, OS Terrain®50, Environment Agency Detailed River Network v3, Centre for Ecology & Hydrology Land Cover Map 2007 (LCM2007), Natural England Agricultural Land Classification, Welsh Government Agricultural Land Classification

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Pollution Sources & Risks: Agriculture Agricultural land use often poses a high risk to water quality, particularly with reference to pesticides. The intensification of farming in the UK over recent decades has led to the increased use of heavy machinery (which leads to compaction and increased runoff) and also widespread chemical treatment of the land, including fertilisers and pesticides. Pesticides are a particular concern for drinking water quality, therefore understanding which crops are being grown in the river catchment and how they are spatially distributed is important for targeting interventions and reducing the risk.

This page explores some of the key variables that influence the degree of risk that agriculture has on river water quality. This includes identifying the location and type of pesticides being applied, as well as assessing the innate land characteristics that influence how pesticides are being mobilised and transported.

Crop Type Detailed crop distribution data is highly valuable for identifying and mitigating pesticide risk as, when combined with local agronomist knowledge, it gives a good insight into which products will be applied and where. Timings of pesticide applications throughout the year can also be inferred. Different pesticides present different challenges for mitigating their risk to drinking water. The physical properties of the pesticide, such as pesticide half life, and also the method of application will greatly affect the way it moves through the landscape. It is therefore important to characterise the type of pesticide risk, in order to design interventions effectively. The Centre for Ecology and Hydrology (CEH) ‘Land Cover Plus: Crops 2015’ dataset provides high resolution information on the distribution of the main arable crop types and improved grassland.

Improved Grassland In the upper Dee sub-catchments (Dee Upper, Alwen, Dee Middle and Ceiriog) there is 460 km² of improved grassland and only 13 km² of arable crops, which are mostly situated in the lower parts. Acid herbicides are likely to be applied to improved pastures

Metaldehyde Risk Oilseed Rape and Winter Wheat are particularly susceptible to slug damage and therefore present a high likelihood of metaldehyde usage. Aldford and Dee Lower have large areas of both these crop types, with a combined sum of 6 km² for Oilseed Rape and 14.6 km² for Winter Wheat

Crop Abundance For the lower sub-catchments (Dee Lower, Pulford, Alyn, Upper Alyn, Clywedog, Aldford, Worthenbury & Wych, Emral Brook and Shell Brook) improved grassland is the most abundant agricultural land use (822 km²), followed by Winter Wheat (60 km²), Maize (55 km²) and Winter Barley (24 km²)

Soil Type

Hydrological Connectivity

Soils are a good indicator of what crops can be grown in a region and hence what pesticides are likely to be used. Furthermore, soil type greatly affects the degree of run-off that occurs and can be linked to issues such as compaction and erosion.

Peaty soils in the upper catchment are good for water quality (when not drained) as they encourage infiltration and also microbial activity promotes the breakdown of compounds. Loamy soils, such as cambisols, make good agricultural land therefore present a higher likelihood of pesticide use.

Topography greatly affects how water moves and accumulates in a river catchment.

By understanding how water moves across the landscape it is possible to identify potential pollution pathways. A hydrological connectivity dataset can be generated using the SCIMAP model, taking into account the topography as well as the size of the upstream contributing areas. This information can be used to target interventions that intercept pollution before it enters a river, such as buffer strips or swales.

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from Strategi® and Boundary-LineTM, OS Terrain®50, Environment Agency Detailed River Network v3, Centre for Ecology & Hydrology Land Cover plus: Crops 2015, EU Soils Database Full Soil Classification 1km grid (WRB-FULL), Surface Flow Index generated using SCIMAP (Durham University)

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Pollution Sources & Risks: Other In addition to agriculture, there are a wide variety of other pollution sources that pose a risk to water quality. Some pollutants are generated at low levels from multiple sources and can occur without significant impact to water quality, unless external factors such as flow conditions or rainfall cause their concentrations in surface water to rise. For example, sewage treatment discharges, industrial wastes and urban runoff. Other pollutants may enter the river in large quantities in a single event, either due to accidental release or unawareness of the impact. These types of pollution inputs are often difficult to predict or to mitigate.

By assessing the distribution of different pollution sources across the catchment it is possible to estimate where the risks to water quality will occur. Combining this information with knowledge about the physical land characteristics, such as topography and hydrology, helps to determine priority areas for intervention measures.

Urban Pollution

Consented Discharges There are a variety of consented discharges present across the catchment, ranging from septic tanks and industrial discharges, to mine waters and combined sewer overflows. It is useful to understand what type of effluent is being released, how likely it is to affect water quality and what conditions cause it to become an issue

The largest centres of population are located in the eastern half of the catchment. Areas with concentrated populations pose a high risk of water pollution due to the increased amount of waste generated from domestic and industrial sources. The lower reaches of the Dee are therefore likely to be affected by urban pollutants, including domestic pesticide usage

Dee Water Protection Zone In 1999 the Dee catchment was designated as the UK’s first, and to date only, Water Protection Zone, which is regulated

by Natural Resources Wales and the Environment Agency.

The ‘Water Protection Zone (River Dee Catchment) (Procedural and Other Provisions) Regulations 1999’ requires a consent to undertake a ‘controlled activity’ (such as storing or using controlled substances) within the River Dee Water Protection Zone (DPZ).

Road Runoff Water that is transported to the river from roads, either via drains or directly, can carry high levels of heavy metals. Also, it is possible that pesticides may be used to manage road verges and railway tracks

Pollution Incidents This Environment Agency dataset is an extract from the National Incident Reporting System and shows where water has been impacted by a category 1 (major) or category 2 (significant) pollution incident between 2001 and 2014.

Category 3 (minor) and category 4 (no impact) incidents are also shown, summarised at the waterbody catchment scale.

Out of the 100 category 1 and 2 pollution incidents, 24 are described as ‘sewage materials’, 13 are ‘organic chemicals/products’, 12 are ‘agricultural materials and wastes’, 10 are ‘oils and fuel’. The majority are located in the lower catchment between Wrexham and Llangollen, as well as in the Alyn sub-catchment. Though it ought to be noted that incidents are more likely to be recorded where population density is higher and unreported incidents may still occur.

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from Strategi® & Boundary-LineTM, OS Terrain®50, Environment Agency Detailed River Network v3, EA Consented Discharges, Population Density Data from the 2011 Census accessed via NomisWeb, Environment Agency Pollution Incidents from the National Incident Reporting System

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Using Models to Identify Risk: Sediment In addition to reviewing the existing datasets to explore catchment-scale risk, computer models can be used to investigate the situation further by simulating real-life processes and generating information about where specific problems are likely to occur. The accuracy of the modelled outputs is dependent on the quality and resolution of the datasets that underpin the model.

A wide range of models have been developed for investigating environmental issues. Two that are particularly useful for modelling pesticide risk are; SCIMAP and the UKWIR Pesticide Risk tool. The former has been run a number of times with user-defined inputs, while the latter is a pre-packaged tool that shows the modelled outputs from the UKWIR pesticide risk mapping process. Both models give a useful insight into where high pesticide risk is likely to occur.

SCIMAP SCIMAP is a model that predicts the spatial distribution of fine sediment erosion risk, by analysing the land cover type, topography and rainfall patterns across a landscape. It’s accuracy is dependent on the quality of the input data and can therefore be used to assess erosion risk at a river catchment scale or at a field-scale.

Sediment erosion is an important factor when considering surface water quality because not only does it itself greatly affect the turbidity and colour of raw water, but it also binds with pesticides and nutrients, thus accelerating their transportation across the land.

Topography High rainfall and steep slopes in the upper parts of the catchment elevate the sediment mobilisation risk

Arable Land Despite the very flat landscape, parts of the lowlands have a high sediment erosion risk due to the physical impact of arable land practices. Soil exposure and processes, such as ploughing and compaction, cause soil erosion to increase

Hydrological Connectivity SCIMAP generates a hydrological connectivity dataset using the topography data, which is then fed into the model (along with land cover and rainfall) to create the sediment erosion risk layer. Hydrological pathways can be seen to influence the overall erosion risk in the inset below. The dark red areas highlight patches of land that are not only at risk from soil disturbance, but are also highly connected to nearby watercourses due to the slope of the land

In-Channel Erosion Risk As well as the land-based sediment erosion risk, SCIMAP also generates an estimation of in-channel erosion risk. This takes into account the upstream area of the receiving channel and the associated dilution effect. The headwaters of the lowland tributaries appear to be at greater erosion risk relative to the upstream area.

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from StrategiÂŽ and Boundary-LineTM, OS TerrainÂŽ50, Environment Agency Detailed River Network v3, erosion risk outputs generated using SCIMAP (Durham University)

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Using Models to Identify Risk: Pesticides UKWIR Pesticide Risk Mapping UKWIR (UK Water Industry Research) has recently produced a pesticide risk mapping tool that can be used by water companies and other stakeholders to identify sites that present a risk to drinking water supply from metaldehyde, oilseed rape herbicides and grassland herbicides.

UKWIR recognised that a single, standardised approach to pesticide risk mapping did not exist, therefore drew on the strengths of existing methods to produce an approach that met the requirements of both the water industry and the regulatory agencies.

The approach quantifies the pesticide risk from agricultural diffuse pollutants and takes into account the losses that occur via surface runoff and drain-flow, as well as leaching from soils to groundwater. The risk factors for each transport pathway vary but include; climate, soil, drain status, slope, landcover, connectivity to water bodies and pesticide properties/usage. These factors are defined for a site using a range of spatial datasets or site inspection. Having defined these factors, the typical annual percentage of pesticide simulated to be lost to surface water (via surface runoff and drain-flow) or leached to groundwater is calculated. The map below shows the risk of both arable and grassland herbicide losses to surface waterbodies at a field-scale.

Lowland Agriculture Most of the grassland in the Lower Dee has a low predicted annual herbicide loss of 5-7.5%. The soil is loamy and drained. The pockets of higher risk areas are mainly due to arable land use, higher risk soils or close proximity to surface water

Upland Grasslands The upland areas have very low risk of herbicide loss due to the lack of agriculture or rushy pasture and peaty, undrained soils

High Risk Grasslands Much of the Middle Dee, Upper Dee and Ceiriog sub-catchment has a relatively high risk of herbicide loss.

This is largely due to the drained, loamy soils, as well as sloping land and proximity to river

Metaldehyde Risk The map above shows the typical annual percentage of metaldehyde estimated to be lost to surface water in the Dee catchment. The results are generated for arable land only. A few small pockets of land show a relatively high risk of metaldehyde loss, primarily in the Pulford subcatchment (inset right) and in the lower Alwen sub-catchment. This is due to a combination of close proximity to surface water, arable land use, sloping land and risky soil type/drainage.

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from StrategiÂŽ and Boundary-LineTM, OS TerrainÂŽ50, Environment Agency Detailed River Network v3, UKWIR Pesticide Risk Mapping at Field-Scale (2016)

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Monitoring to Target Action: Routine Monitoring In order to refine knowledge about water quality risk further, the use of monitoring data can be very important. A wide range of datasets, such as landcover, crop type and sediment erosion models, have been used to identify where pollution risk is occurring either at source or along its pathway. Conversely, water quality monitoring measures the impacts of pollutants at the receptor; the receiving waterbody.

A well-designed monitoring plan, with sufficient temporal and spatial resolution, can provide extremely valuable information, enabling the user to closely monitor the quality of river water, as well as gain a better understanding of where and how pollutants are entering the river.

Water Framework Directive All the water bodies in England and Wales are monitored by the Environment Agency and Natural Resources Wales to assess whether they comply with the objectives of the EU Water Framework Directive (WFD). The aim is for all water bodies to achieve ‘good ecological status’ by 2021, which includes biological, chemical and physical factors. The WFD monitoring results and ‘Reasons for Not Achieving Good’ dataset provide a useful insight into water quality across the river catchment.

Heavy Metals A number of water bodies in the upper Alyn and Clywedog catchments are failing for zinc, lead and/or cadmium. This is potentially linked to abandoned mines in the area, but further investigation is required

Multiple Issues Many of the lowland water bodies (particularly to the east of the main river) are failing for multiple elements, including BOD, phosphate, macrophytes and ammonia. These could be caused by a combination of sewage discharge, fertiliser slurry, or manure runoff, or land spreading of waste

pH Several water bodies in the upper Dee catchment are failing for pH. A number of reasons are cited in the database, including; natural conditions, atmospheric deposition and forestry

Tributyltin Compounds The Dee water body (from Ceiriog to Alwen) is a heavily modified water body and is failing for tributyltin compounds. Possible causes include anti-fouling agents for boats and timber preservatives

Deesit and IPS Water quality sampling on the River Dee is currently carried out at eight sites within the catchment, twice per day, for the Dee Steering Committee. The data is then issued to the abstracting water companies and the environmental regulators in a twice-daily, Dee Situation (Deesit) Report.

Six of these Deesit sites are located on the main river, three of which also have on-line monitoring carried out at Intake Protection Stations (IPS). The remaining two sites are located in the lower catchment on tributaries of the Dee; Clywedog and Alyn. 2,4-D, Mecoprop and MCPA are measured at three of the sites. Furthermore, United Utilities measure Metaldehyde at six sites along the river. Data from these monitoring sites is used to regularly check the quality of water that is being abstracted and ensure that pesticide risk is closely managed.

Metaldehyde Concentration (µg/L) Clywedog at Pickhill 0.15 0.1 0.05 0

2013

2014

2015

2016

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from Strategi® and Boundary-LineTM, OS Terrain®50, Environment Agency Detailed River Network v3, Natural Resources Wales 2015 WFD Surface Water Body Status and Objectives, Environment Agency Cycle 2 Waterbody Catchments, Deesit Monitoring Sites and United Utilities Monitoring Data provided by United Utilities

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Monitoring to Target Action: Passive Sampling Chemcatcher Monitoring

Pesticides by Season

Chemcatchers are passive sampling monitoring devices, developed by the University of Portsmouth, that can be used to measure concentrations of pollutants in river systems. United Utilities have deployed Chemcatchers at 13 sites across the Dee catchment, with the ability to measure metaldehyde and 18 different acid herbicides at each site. The devices were deployed at each site for two week periods, consecutively throughout 2016. The aim of this monitoring program was to better understand the concentration of pesticides in the river water over continued periods of time (spot samples can often miss pesticide spikes) and also to assess the spatial characteristics of pesticide application across the catchment.

The chart below shows the average amount of pesticides found at all sites across the catchment for each of the seasons. It is useful to see when each pesticide is applied throughout the year.

For example, MCPA had a relatively high average concentration in spring and summer month, yet autumn and winter measurements were low.

MCPA 2,4-D Clopyralid Mecoprop Fluroxypyr Triclopyr Spring

Lowland Trends

Bromoxynil

Summer

Bentazone

Autumn

In the lowlands, the highest pesticide application rates are generally in the spring and summer, though certain sub-catchments show high concentrations in autumn, e.g. Golbourne Brook

Dicamba

This page shows broad catchment trends that are evident from the 2016 dataset. More detailed site-scale trends are explored on the following page.

Metaldehyde

Winter

Summer Applications All sites in the middle and upper reaches of the catchment generally have low pesticide concentrations, however, some show an increase in the summer months

Time Weighted Averages Chemcatchers adsorb pesticides during each two week deployment. The total amount of pesticide on each disc at the end of deployment is used to calculate a Time Weighted Average, which takes into account the length of the deployment period and the uptake rate for each pesticide

Average Concentration (µg/L)

0.2

MCPA 2,4-D Clopyralid Mecoprop Fluroxypyr Triclopyr Dicamba Bromoxynil Bentazone Metaldehyde

0.15

0.1

0.05

0

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Temporal Trends This chart shows the average concentration of each of the top ten pesticides (based on annual mean) for each deployment throughout the year, for all sites combined. MCPA shows the highest average for a single deployment period, that is the first two weeks of June. 2, 4-D levels are also high around this time.

Furthermore, clopyralid concentrations are consistently quite high compared with the other pesticides, though it does not experience such distinctive peaks as others. Certain pesticides show spikes in spring and autumn, as well as summer, while metaldehyde is the only pesticide to show a noticeable increase in December.

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from Strategi® and Boundary-LineTM, OS Terrain®50, Environment Agency Detailed River Network v3, Chemcatcher® 2016 data provided by United Utilities, Environment Agency Cycle 2 Waterbody Catchments

Monitoring to Target Action: Passive Sampling Chemcatcher Results The charts on this page illustrate the results from the Chemcatcher devices deployed in 2016 for the ten most abundant pesticides.

Aldford Brook and Coddington Brook stand out as being particularly problematic, with high amounts of 2,4-D and MCPA in the late spring/early summer. Shell Brook also shows some noticeable spikes in certain pesticides during the summer months. Other pesticides, such as clopyralid and fluroxypyr, are present consistently at lower levels for many sub-catchments all year round.

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from Strategi® and OS Terrain®50, Environment Agency Detailed River Network v3, Chemcatcher® 2016 data provided by United Utilities, Environment Agency Cycle 2 Waterbody Catchments

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Data and Evidence Summary Using the wide range of data and evidence it is possible to prioritise the sub-catchments according to how much of a risk they present to drinking water quality. Catchment-scale data allows the user to identify regions where issues may be likely to occur, while the monitoring and modelling results allow the user to target interventions more accurately.

A risk score for each sub catchment of the River Dee drinking water catchment has been determined for its potential to leach metaldehyde or acid herbicides, using the wide range of data and evidence, as well as local knowledge. The scoring was ratified by participants of the Upper and Middle Dee Steering Groups, organised by the Welsh Dee Trust catchment advisors. The steering groups include representatives from the following organisations; Environment Agency, Natural Resources Wales, Snowdonia National Park, Farming and Wildlife Advisory Group, Farming Connect, Farmer and Landowner representatives, National Farmers Union Wales, National Farmers Union, Farmers Union of Wales, Country Land and Business Association and Institute of Biological, Environmental and Rural Sciences. The priority sub-catchments are shown in the maps below.

Acid Herbicides

Sub-Catchment

Risk Score

Metaldehyde

Reason

Acid Herbs.

Metaldehyde

Aldford Brook

Very High

High

Large proportion of the catchment is arable (40%) and improved grassland (50%), suggesting high use of acid herbicides. This is confirmed by the Chemcatcher results. Also, there is a large golf course, where the use of acid herbicides to control weeds is possible. The large area of oil-seed rape and winter wheat could explain the presence of metaldehyde.

Pulford Brook

Very High

High

Predominately improved pasture or cereals, usage of acid herbicides is high in both. Land is used for growing crops such as stubble turnips or forage rape to accommodate over wintering lambs and ewes. Autumn-sown brassicas are susceptible to slug damage. Chemcatchers show spikes in several acid herbicides in June and July, with bromoxynil being particularly high. Metaldehyde is also present.

Shell Brook

Very High

High

Predominately improved pasture or cereals, usage of acid herbicides is high in both. Chemcatcher data found relatively high levels of acid herbicides in the spring and summer months, particularly MCPA and 2,4-D. Metaldehyde also present with highest level recorded in December.

Worthenbury & Wych

High

High

Predominately improved pasture or cereals, usage of acid herbicides is high in both. There is some winter cereal production and autumn-grown grass re-seeds presenting a risk of metaldehyde. Large number of dairy farms.

Chemcatchers show noticeable spikes in several acid herbicides in June and for metaldehyde in May and December.

Emral Brook

High

High

Predominately improved pasture or cereals, usage of acid herbicides is high in both. There is some winter cereal production and autumn-grown grass re-seeds presenting a risk of metaldehyde. Chemcatchers show spikes in several acid herbicides (including MCPA, clopyralid and mecoprop).

Alyn

High

High

Predominately improved pasture or cereals, usage of acid herbicides is high in both. Water sampling has indicated that metaldehyde is reaching the watercourses.

Clywedog

High

High

Predominately improved pasture or cereals, usage of acid herbicides is high in both. Land is used for growing crops such as stubble turnips or forage rape to accommodate over wintering lambs and ewes. Autumn-sown brassicas are susceptible to slug damage.

Dee Lower (Chester Weir to Ceiriog)

High

Moderate

Predominately improved pasture or cereals, usage of acid herbicides is high in both. Metaldehyde risk is lower as the area is prone to flooding and therefore crops that are susceptible to slug damage are not likely to be grown.

Dee Middle (Ceiriog to Alwen)

Moderate & High

Ceiriog

Low & Moderate

Low

Much of this catchment is dominated by grade 5, acidic, wet and peaty land that is not suitable to grow quality grassland or crops. The land grade improves slightly in the lower reaches, where rough grazing dominates.

Chemcatchers show very low levels of acid herbicides or metaldehyde.

Upper Alyn

Low

Low

Land is dominated by semi-improved grassland or moorland therefore crops that are susceptible to slug damage are unlikely to be grown.

Dee Upper (above Alwen)

Very Low, Low & Moderate

Low

Land is classified as grade 4 and 5 and thus mainly unsuitable for arable cropping. Due to climatic conditions and topography little of the ground is ploughed resulting in low levels of re-seeding or arable cropping and thus little usage of metaldehyde. Acid herbicide risk increases further down the catchment due to the presence of grasslands used for grazing or silage/hay.

Alwen

Very Low & Moderate

Low

In the upper Alwen, agricultural conditions are unfavourable with very acidic and peaty soils making growing crops very difficult. Acid herbicide risk increases in the lower parts due to an improvement in agricultural land. Steep slopes have been cultivated and drained resulting in improved grassland.

A vast amount of the area is either grade 4 or 5 land on very steep ground, making arable farming difficult. Acid Low & Moderate herbicide risk increases further down the catchment due to the presence of grasslands used for grazing or silage/hay.

Chemcatchers show high spikes of MCPA in June at Morwynion.

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from StrategiÂŽ, Environment Agency Detailed River Network v3, Environment Agency Cycle 2 Waterbody Catchments

14

Action to Improve Water Quality The River Dee Water Quality Improvement Project aims to deliver coordinated and well-targeted interventions that encourage best-practice and reduce the risk of pesticides and other pollutants from entering surface water. A number of organisations have collaborated to implement these measures, including; United Utilities, Dee Valley Water, Environment Agency, Natural Resource Wales, Reaseheath College, The Welsh Dee Trust and The Woodland Trust.

The partnership has closely reviewed a wide range of data and information concerning pesticide risk in the catchment, which has enabled them to deliver well-targeted mitigation measures on the ground. The measures are primarily focused on farm advice and support for best practice pesticide use, though some nonagricultural measures have also been implemented.

Farm Advice Throughout 2016, farm advisors from the Welsh Dee Trust and Reaseheath College worked with the local farming community to improve farming practices and reduce their impact on water quality. A number of techniques were piloted in two sub-catchments; Alwen and Alyn, while other measures were made available to the whole catchment. The map below shows where free ADAS Health Check farm visits were carried out and which of these resulted in Farmscoper reports being generated. Some of these visits led to grants being awarded for capital works, such as improved guttering and downpipes. Furthermore, FARMSCOPER SUMMARY a number of farms were supported to apply for the Glastir Small Grants scheme, which would provide Savings with Losses measures funds for capital works to improve water quality.

Water Management Plans As well as the ADAS visits, 100 additional farm visits have been carried out in the middle/lower sub-catchments in 2016.

Many of these resulted in the production of Water Management Plans

Farmscoper Reports

FARMSCOPER SUMMARY Losses

Savings with measures 280 kg

Nitrate

7,267 kg

Phosphorus

193 kg

18 kg

Sediment

118,754 kg

5,283 kg

Pesticides

4.00

0.84

Farmscoper is a decision-support tool created by ADAS that can be used to assess the degree of diffuse agricultural pollution generated on a farm and quantify the impacts of mitigation measures on these pollutants. In 2016, 20 out of 34 farm visits led to the production of Farmscoper reports

Nitrate

3,079 kg

Phosphorus

200 kg

305 kg 27 kg

Sediment

30,048 kg

1,300 kg

Pesticides

0.10

0.03

Capital Grants Improvements to farm infrastructure can help to reduce the likelihood of pesticides and other pollutants from entering watercourses. For example, improving drainage systems in machinery wash-down areas or resiting gateways away from high risk areas

Pesticide Types Consigned

Farmers across the Dee catchment were given the opportunity to have unwanted, out-of-date or unapproved pesticides disposed of free-of-charge.

Twenty-six farms took part in the pesticide amnesty between October 2016 and February 2017.

A total weight of 1,833kg of pesticides were consigned, ranging from 1kg to 450kg for any one site. The types of pesticides varied greatly, including products such as Starane, Aldrex, Sprint, Hoegrass, Jaguar and Agritox.

The number of different pesticides found at any one farm ranged from one to thirty-nine.

No. of Farms

Pesticide Amnesty

1-6

7-11 12-16 17-21 22-26 27-31 32-36 37-41

No. of Pesticides

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from Strategi® and Boundary-LineTM, OS Terrain®50, Environment Agency Detailed River Network v3, Delivery Data provided by United Utilites and Welsh Dee Trust

15

Action to Improve Water Quality Additional Farm Support In addition to farm advice and capital grants, many other types of support have been made available to farmers in the Dee catchment. These include subsidised ferric phosphate-based slug pellets (as an alternative to metaldehyde), free sprayer testing, subsidised sprayer training courses and free weed wiper hire. The aim of these measures is to reduce the risk of pesticides entering watercourses, while also benefitting the farmer by improving the farm business. By increasing the precision with which pesticides are applied to the land, as well as ensuring equipment is functioning effectively and efficiently, farmers can maximise profit by reducing pesticide losses yet maintaining productivity. The map below shows additional farm support measures provided in 2016.

Sprayer Training Subsidised pesticide sprayer training courses were offered to farmers across the catchment.

The following modules were promoted; PA1 – foundation module, PA2 – boom sprayer, and PA6 – hand held applicators. 7 farmers participated in the sprayer training

Sprayer MOTs Free sprayer MOTs were offered to farmers in the Alwen and Alyn subcatchments. The tests ensured that chemical sprayers were maintained at the National Sprayer Testing Scheme standard. 25 sprayer MOTs were carried out and an additional 4 were exempt due to the age of the sprayer or the owner choosing to purchase a new one

Industrial Pollutant Audits In addition to agricultural measures, United Utilities, Groundwork and Natural Resources Wales have been offering local industries the opportunity to receive free, confidential pollution prevention advice. The aim is to enable businesses to reduce water pollution risks from their activities, avoid expensive fines and clear up costs associated with pollution incidents and ensure that the River Dee is protected from accidental chemical spills from local business. In 2016, twenty five audits were carried out in total.

Slug Pellet Switch A subsidy of 50% of the cost of ferric phosphate-based slug pellets was offered to anyone farming in the River Dee drinking water catchment on receipt of an agronomist order. These slug pellets are a preferred alternative to metaldehyde, which is very soluble in water and extremely difficult to remove using conventional water treatment

Weed Wiper Hire Weed wipers use glyphosate to target the roots of weeds and prevent them from reestablishing, unlike MCPA. It is a preferential method to boom spraying or knapsack application because it reduces the likelihood of damaging favourable grassland species and it uses considerably less chemicals, leading to a financial saving for the land owner. The weed wiper was used at 85 different sites on 23 farms. The majority of sites were treated for rushes and thistles, while others included nettles, bracken and docks

Delivery Summary By collating and analysing a wide range of datasets the Dee catchment partnership have assessed the pesticide risk across the catchment and targeted actions to mitigate the risk accordingly. In summary, the following outputs were delivered in 2016: • • • • • • • • • •

34 ADAS farm health checks (20 number led to Farmscoper reports) 2 capital grants for farm works based on ADAS recommendations 100 farm visits in the Aldford, Lower Dee, Wych and Worthenbury, and Emral sub-catchments – 67 led to Water Management Plans, 39 had soil testing, 23 led to Nutrient Management Plans and 35 had potential grant opportunities 6 small grant applications (Glastir) 85 sites were treated using the Weed Wiper, at 23 different farms 4 farms receiving subsidised slug pellets 25 sprayer MOTs 7 farmers signed up to PA1, PA2 and PA6 sprayer courses 26 farms took part in the pesticide amnesty, resulting in the consignment of 1,833 kg of pesticides 25 industrial pollutant audits

The maps on this page contain the following datasets (either in raw or processed form): Ordnance Survey infrastructure datasets from Strategi® and Boundary-LineTM, OS Terrain®50, Environment Agency Detailed River Network v3, Delivery Data provided by United Utilites and Welsh Dee Trust

Photo: Flickr, Reflection of a Tree (River Dee) by Dunnock_D (CC BY-NC 2.0)