Llanwern Rail Facilities - Phase 1 Planning Water Quality Assessment Report

September 2018

Transport for Wales (TfW) 367590-WTD-CAR-2657

Mott MacDonald Fitzalan House Fitzalan Road CF24 0EL United Kingdom

T +44 (0)29 2046 7800 F +44 (0)29 2047 1888 mottmac.com

Transport for Wales (TfW) Southgate House Wood Street Llanwern Rail Facilities - Cardiff 367590-WTD-CAR-2657 CF10 1EW Phase PiMS 1 Planning Mott MacDonald Water Quality Assessment Report

September 2018

Mott MacDonald Limited. Registered in England and Wales no. 1243967. Registered office: Mott MacDonald House, 8-10 Sydenham Road, Croydon CR0 2EE, Transport for Wales (TfW) United Kingdom 367590-WTD-CAR-2657

Mott MacDonald | Llanwern Rail Facilities - Phase 1 Planning Water Quality Assessment Report

Issue and Revision Record

Revision Date Originator Checker Approver Description A 19/09/2018 K. Bishop M. Ross L. Strickland Draft Issue – For TfW Review Only B 28/09/2018 K. Bishop M. Ross L. Strickland Issue for Pre-Application Consultation

Document reference: 367590-WTD-CAR-2657

Information class: Standard

This document is issued for the party which commissioned it and for specific purposes connected with the above- captioned project only. It should not be relied upon by any other party or used for any other purpose.

We accept no responsibility for the consequences of this document being relied upon by any other party, or being used for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other parties.

This document contains confidential information and proprietary intellectual property. It should not be shown to other parties without consent from us and from the party which commissioned it.

This Repor t hasbeen prepared solely for use by the party which commissioned it (the 'Client') in connection with the captioned project. It should not be used for any other purpose. No person other than the Client or any party who has expressly agreed terms of reliance with us (the 'Recipient(s)') may rely on the content, information or any views expressed in the Report. This Repor tis confident ial and contains propriet ary intellectual property and we accept no duty of care, responsibility or liability to any other recipient ofthis Report. No representation, warrant yor undertaking, expr ess or implied, is made and no responsibilit yor liability is accepted by us to any par ty other than the Client or any Recipient(s), as to the accuracy or completeness of the inf ormation contained in this Repor t. For the avoidance of doubt this Report does not in any way purport to include any legal, insuranceor financial advice or opinion.

We disclaim all andany liability whether arising in tort, contract or ot herwise which we might otherwise have to any party ot her than the Client or the Recipient(s), in respect of this Report, or any information contained in it. We accept no responsibility for any error or omission in the Report which is due to an error or omission in data, inf ormation or statements supplied to us by other par ties including the Client (the 'Data'). We have not independently verified the Data or otherwise examined it to deter mine the accuracy, complet eness, sufficiency for any purpose or feasibility for anyparticular outcome including financial. For ecast s presented in this document were prepared using the Data and the Report is dependent or based on the Data. Inevitably, some of the assumptions used to develop the forecasts will not be realised and unanticipat ed events and circumstances may occur. Consequently, we do not guarantee or warrant the conclusions contained in the Report as there are likely to be differences between the forecasts and the actual results and those differences may be material. While we consider that the inf ormation and opinions given in this Repor tare sound all par ties must rely on their own skill and judgement when making use of it. I nf or m ation andopinions arecurrent only as of the date of the Report and we accept no responsibility for updating such inf or mation or opinion. It should, ther efore, not be assumed that any such infor mation or opinion continues to be accurate subsequent to the date of the Report. Under no circumstances may this Report or any extract or summar y thereof be used in connection with any public or private securities offer ing including any relat ed memorandum or prospectus for any secur ities offering or stock exchange listing or announcement. By acceptance of this Report you agree to be bound by this disclaimer. This disclaimer and any issues, disput es or claims arising out of or in connection with it (whether contractual or non-contract ual in nature such as claims in tort, from breach of statute or regulation or other wise) shall be gover ned by, and construed in accordance with, the laws of England and Wales to the exclusion of all conflict of laws principles and rules. All disputes or claims arising outof or relating to this disclaimer shall be subject to the exclusive jurisdiction of the English and Welsh courts to which theparties irrevocably submit.

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Mott MacDonald | Llanwern Rail Facilities - Phase 1 Planning Water Quality Assessment Report

Contents

1 Introduction 1 1.1 Project Description 1 1.2 Scope of Works 1 1.3 Site Location 1 1.4 Purpose of this Technical Note 2

2 Water environment baseline 3 2.1 Baseline water environment 3 2.2 WFD Waterbodies 3 2.3 Protected Areas 4 2.4 Gwent Levels Water Quality Requirements 4

3 Water Quality Assessment 5 3.1 Potential Risks to Water Quality 5 3.2 Mitigation of Risks to Water Quality 5

4 Summary and Conclusions 7

Appendices 8

A. Drainage Ditches 9

B. NRW Advice Note 11

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1 Introduction

1.1 Project Description Mott MacDonald has been commissioned by Transport for Wales (TfW), on behalf of , to prepare and submit a planning application, seeking full planning permission for the design and construction of a 1.6km long Major Events Stabling Line (MESL) on land adjacent to the existing Tata Steelworks Service Lines in Llanwern, South Wales. This is Phase 1 of the Llanwern Rail Facilities Programme.

The MESL will be used for stabling of rolling stock for major events in the area, to enable flexibility for future train requirements, and proving of trains prior to use on the rail network. The MESL will be electrified in a future phase of work. This proposed 1.6km length of MESL to the west of Monks’ Ditch was formerly known as Option 6a.

The wider Llanwern Rail Facilities Programme will include an extension of the MESL by circa 2.4km east (to achieve a total length of circa 4km), electrification of the MESL, a new and passenger line (including Park & Ride and footbridge), and connections to the (Relief Lines). The further phases of the project will be the subject of a subsequent planning application.

The key parameters for the Scheme are listed below:

● Whole Site area is 3.1 hectares. This land is contained within the red line boundary shown on the Site Location Plan (Drawing number 367590-MMD-48-XX-DR-C-0001); and ● The Site length is approximately 1.6km long and 19m wide.

1.2 Scope of Works The General Arrangement drawings (Drawing numbers 367590-MMD-48-XX-DR-C-0002 to 367590-MMD-48-XX-DR-C-0005) demonstrate the project scope which includes the design and construction of the following:

● A single track stabling line (MESL) circa 1.6km long; ● Associated earthworks and landscaping; and ● Drainage and other engineering works. In order to obtain full planning permission for Phase 1, we have carried out the outline design and technical assessment of the above scope, as well as multiple assessments in terms of ecology, environment, heritage and archaeology.

1.3 Site Location The proposed rail development Site is located approximately 8 miles east from the centre of Newport, South Wales (Figure 1.1).

The Site is aligned roughly west – east and bordered by the existing South Wales Mainline to the north and the Tata Steelworks to the south. Along the southern boundary of the steelworks site runs the A4810 which links the M4 from junction 23A at Magor with the A48 at Liswerry (a predominantly residential suburb on the south-eastern side of Newport. The site is more widely bordered by the M4 which runs approximately two and a half miles to the north and the Severn

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Estuary which lays approximately three miles to the south. The Gwent Levels to the south is a significant area of wetlands.

The existing South Wales Mainline passes north of the proposed Site and provides opportunity for transport links for both passengers and freight.

Figure 1.1: Proposed Location Plan

Source: OS Open Data

1.4 Purpose of this Technical Note This Technical Note comprises a high-level assessment of the impact that the Scheme has on the water environment, specifically, on water quality. For the purposes of this assessment, the term ‘water environment’ includes surface waterbodies within the Site, and within 1km downstream of the Site (which includes waterbodies within the Gwent Levels SSSI).

The Technical Note adopts a simple approach, outlining the baseline water environment, identifying and evaluating potential impacts the Scheme could have on water quality. This assessment loosely adopts a Water Framework Directive ‘screening’ assessment format, and is structured as follows:

● 1: Introduction to the Scheme; ● 2: Outline of baseline water environment, protected areas and water quality; ● 3: High-level water quality assessment, identifying and evaluating risks to water quality; and ● 4: Summary and conclusions.

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2 Water environment baseline

2.1 Baseline water environment Llanwern lies just north of the Gwent Levels, an area of low-lying estuarine alluvial wetland (<5mAOD1) adjoining the north bank of the Severn Estuary. Historically, the area has been subject to successive land reclamation. As such, the natural features having been extensively modified through the installation of a network of drainage ditches (known locally as reens), which drain the low-lying landscape. The drainage network generally takes water from north to south, discharging directly into the Severn Estuary; most outfalls have tide-flaps or sluices for flood protection purposes. The reens can convey significant quantities of water and provide habitat for a variety of invertebrates, aquatic species. Much of the Gwent Levels is designated as a Site of Special Scientific Interest (SSSI)2.

Within the Site, there are multiple inter-linking reen systems (plans showing drainage ditches shown in Appendix A3), which are managed by the Internal Drainage District (IDD), which is part of Natural Resources Wales (NRW). These reens are mostly small channels (between 1-3m width), flowing from north to south, and culverted beneath the main railway and sidings. The embankments of these reens are typically heavily vegetated by hydrophilic plants, but the embankments of drainage ditches within land owned by Tata Steel are routinely cleared of vegetation. Most of the reens on the Site drain into the Monks’ Ditch, a main river4 (owned and managed by NRW) that flows from north to south along the eastern boundary of the Site, in a concrete channel that is hydraulically separated from the surrounding land. Some of the reens towards the west of the Site drain into Longditch Reen and then Julian’s Reen; large reen channels flowing from north to south towards the Gwent Levels.

2.2 WFD Waterbodies5 The Scheme lies within the management catchment, which is situated within the Severn River Basin District (RBD) – River Basin ID: 9. This RBD is covered by the Severn River Basin District Management Plan (Environment Agency and Natural Resources Wales, 2015)6.

The Site itself lies within the Monks’ Ditch – source to Wainbridge (GB109056026850) WFD waterbody. This river waterbody lies upstream of and drains into the Severn Estuary ‘Severn Lower’ transitional waterbody (GB530905415401). The Scheme is underlain by the Usk Deonian Old Red Sandston groundwater body (GB40902G201700).

Monks’ Ditch – source to Wainbridge (GB109056026850) river waterbody is designated an artificial waterbody, for ‘land drainage’ and ‘wider environment’ uses. The waterbody had an overall ‘moderate’ status in 2015, with an objective to achieve ‘good’ status by 2021. Known pressures on the waterbody include intermitted sewage discharge and unsewered domestic

1 Metres Abov e Ordnance Datum (mAOD) – altitude as viewed on contemporary OS mapping, as viewed at https://www.bing.com/maps (accessed August 2018). 2 https://www.rspb.org.uk/reserves-and-events/reserves-a-z/newport-wetlands/ 3 Existing drainage plan produced by Halcrow (2006) 4 Main riv ers are statutory rivers in England and Wales. 5 Inf ormation on WFD waterbodies obtained from Water Watch Wales online portal, Cycle 2 waterbodies. 6 Accessed online: https://www.gov.uk/government/collections/river-basin-management-plans-2015#severn-river-basin-district-rbmp:- 2015

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sewage. The main element preventing the waterbody from achieving good status is the mitigation measures assessment, as there are a number of measures that remain outstanding.

2.3 Protected Areas The Gwent Levels (situated immediately south of the Site) are a nationally important wetland and many areas have been designated as SSSIs. Although Llanwern village and the Tata Steelworks sites are not within a protected area, they lie immediately upstream of, or are adjacent to multiple SSSIs including:

● Gwent Levels: Nash and Goldcliffe SSSI; ● Gwent Levels: Whitson SSSI; ● Gwent levels: Redeick and Llandevenny SSSI; and ● Magor Marsh: SSSI. The Gwent Levels – Nash and Goldcliff SSSI is located immediately south of the Site (Central NGR ST358844), with Monks’ Ditch flowing centrally through the SSSI. Given its close proximity, this SSSI is in hydrological connectivity with the Site because the reens flow directly through it. The Scheme could, therefore, have an impact on water quality within the SSSI. In addition, the Newport Wetland National Nature Reserve is located approximately 3km south of the Site, which lies between the Severn Estuary and on the South Wales Coast. The Newport Wetlands include wetland, reedbed and estuary habitats. Finally, the Severn Estuary (situated over 5km south of the study area) is also designated as a SSSI, Ramsar Site, Special Protection Area (SPA) and Special Area of Conservation (SAC).

2.4 Gwent Levels Water Quality Requirements Proposed works that are within or close to the Gwent Levels SSSIs must adhere to a defined set of water quality standards that have been produced by NRW. These standards are designed to reflect and preserve the unique environment of the Gwent Levels. NRW has produced a briefing note (Appendix B) to advise on water quality requirements within the Gwent Levels ditch system7.

As noted above, the Gwent Levels are poorly connected to nearby rivers. Most water in the reen system comes from precipitation (rather than from upstream watercourses) and therefore the reen system can get very dry during the summer months. This also means that discharges into the reen system may have more significant impacts on water quality in summer months, because there is less flow to dilute contaminants which may have entered the watercourse, potentially comprising water quality within the reens. NRW’s advice note stipulates that the design of any discharge into the Gwent Levels ditch system needs to either:

● Meet or exceed water quality standards in Table 28 of the advice note; or ● If these standards are already met, discharge water of equivalent quality to measured values in order to avoid deterioration.

7 NRW Brief ing Note on Water Quality Standards for the Gwent Levels Ditch System (December, 2016). 8 Table 2 of the briefing note is provided in Appendix B.

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3 Water Quality Assessment

3.1 Potential Risks to Water Quality The main element of the Scheme which has potential to affect water quality are the outfalls that will discharge surface track drainage from the proposed railway line into the existing reen system. The proposed drainage elements for the Scheme are shown in drawings 367590-MMD- 48-XX-DR-C-0300 and 367590-MMD-48-XX-DR-C-0301.

In total there are five outfalls proposed to collect and discharge track drainage into the surrounding reens, which are upstream of the Gwent Levels SSSI. These outfalls present a potential risk to water quality, as the oil-based contaminants typically contained within track drainage have potential to reduce water quality and damage aquatic habitats within the ditch system. Hydrocarbon contaminants could be released as part of routine activities or through accidental spillages, and drain into the reens. This risk could also be transferred downstream, via the reens, into the Gwent Levels SSSI. Each outfall has been designed to be fitted with an oil separator, to remove hydrocarbons (e.g. oils, fuel. Greases) that may be contained within the track drainage. Oil separators will effectively separate the oil-based contaminants from the water, releasing the water and retaining the contaminants for removal. The oil interceptors will reduce the risk hydrocarbon contaminants entering receiving watercourses downstream.

3.2 Mitigation of Risks to Water Quality The provision of five oil separators (Class 1 or similar) to be fitted at each drainage outfall will ensure that the majority of contaminants in the track drainage are removed, and that the subsequent discharge will not result in significant deterioration of water quality within the reen system. The residual level of contaminants in the water that is discharged to the reen system. The residual level of contaminants in the water that is discharged to the reen system is likely to be negligible, provided that the oil separators are designed, installed and maintained properly.

In addition to the provision of oil separators, there are other factors which should be taken into consideration that will reduce the risk to water quality. These include:

● The proposed MESL is a stabling line which will not have regular traffic as on the main line. For this reason, there will typically by a lower volume of traffic on the lines compared with typical mainline tracks, meaning the notional levels of contaminants released will be lower; ● The proposed MESL has been designed to sit on a granular ballast bed. Ballast is part of the railway drainage system, but also provides an opportunity for contaminants and other particulate matter to be filtered out of the water, before being treated by the oil interceptors; and ● The Ground Conditions and Contaminated Land Report (Mott MacDonald, 2018) for the Scheme9 concluded that the Site will not provide a source of contamination, reducing the risk of horizontal/vertical contaminant leaching into the reen systems via groundwaters. Overall, given the embedded mitigation measures outlined above, it is considered that the proposed track drainage treatment will be sufficiently treated such that the risk to water quality in the reen system, is negligible. The quality of water that discharges into the Gwent Levels

9 : Llanwern Rail Facilities – Phase 1 Planning – Ground Conditions and Contaminated Land Report (Mott MacDonald, 2018).

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SSSI is therefore expected to meet the existing water quality standards, preventing the risk of water quality deterioration when compared with the baseline situation.

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4 Summary and Conclusions

The high-level water quality assessment indicated that the Scheme presented a very low risk to water quality within the study area. The proposed MESL at Llanwern is unlikely to be a major source for contamination given the design of the Scheme. More specifically, this includes a low traffic volume and design of the line on a granular ballast bed, and due to the inclusion of oil separators that will comprehensively treat the track for any contaminants. The proposed track drainage treatment will be sufficiently treated such that the risk to water quality in the reen system is negligible. Therefore, the quality of water that discharged into the Gwent Levels SSSI is expected to meet the existing water quality standards, preventing the risk of water quality deterioration as a result of the Scheme.

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Appendices

A. Drainage Ditches 9 B. NRW Advice Note 11

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A. Drainage Ditches

Existing drainage plan produced by Halcrow (2006)

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B. NRW Advice Note

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Briefing

note

NRW Advice on Water Quality Standards to be used for Impact Assessment of the on the Gwent Levels Ditch System

Background

Welsh Ministers have responsibility for motorways and trunk roads in Wales. On this basis, Welsh Government are developing proposals to build a new section of motorway between Junctions 23 and 29 of the existing M4 in Newport, a project known as the M4 Corridor around Newport (M4 CaN).

The proposed route passes to the south of the existing motorway, immediately to the south of the Tata Steelworks at Llanwern, on the Caldicot Level, would involve a new crossing of the Rivers Usk and Ebbw and passes to the south of the Quins Radiator Plant, on the Wentlooge Level. Consequently the proposals fall within and would directly affect (i.e. both construction upon and drainage into the network) the northern sections of the following Gwent Levels: Sites of Special Scientific Interest (SSSIs):

 Gwent Levels: St Brides SSSI  Gwent Levels: Nash and Goldcliff SSSI  Gwent Levels: Whitson SSSI  Gwent Levels: Redwick and Llandevenny SSSI

In addition the following sites could potentially be indirectly affected, due to being part of the same drainage system:

 Gwent Levels: Rumney and Peterstone SSSI  Gwent Levels: Magor Marsh SSSI  Magor Marsh: SSSI  Gwlyptiroedd Casnewedd/ Newport Wetlands SSSI

Consultants working on behalf of Welsh Government, as part of a Joint Venture, have drawn up a preliminary design for the new stretch of motorway. This work includes a drainage strategy, designed to take surface water from the carriageway and convey it, primarily through open, grass-lined channels to a number of water treatment areas (WTAs) along the proposed route. The purpose of the WTAs is to treat water to a standard suitable for discharge into the drainage system (network of reens and ditches) of the Gwent Levels SSSIs, through treatment which includes the use of oil interceptors and reed beds.

Approved Version – 12 December 2016

As NRW, we need to develop a full remit view on acceptable water quality, across a range of determinants, to be discharged into the Gwent Levels SSSI drainage system. Different water quality standards apply and this paper provides advice on the most appropriate water quality standards to apply for impact assessment, taking into account:

 Relevant legal frameworks and requirements.  The applicability of the relevant standards to the environment in question;  The likely impacts of road construction and operation on water quality and / or freshwater ecosystems;

Summary of Relevant Legislation

The Water Framework Directive (WFD) requires European Member States to aim to reach Good Surface Water Status which comprises Good Chemical Status and Good Ecological Status (with certain exceptions and derogations possible) for all water bodies by a named deadline as outlined in the relevant River Basin Management Plan.

The objectives vary according to the type of water body involved. Ecological Status is measured against environmental standards linked to the most applicable pressures in the relevant water body as identified by a risk assessment. Monitoring methods (termed classification tools) are standardised, evidence-based and inter-calibrated across member states.

Article 1 of the WFD sets out its main purposes, which includes preventing further deterioration of waters and to protect and enhance aquatic ecosystems, promote sustainable use, reduce discharges, emissions and losses of priority substances. The core measures in Article 4 of the WFD are those necessary to prevent deterioration in the status of surface water, to protect, enhance and restore surface waters.

 Although WFD is European level legislation and has robust, evidence-based standards, there are problems with its applicability in the Gwent Levels environment. These are discussed below;  All water bodies in the Gwent Levels system are designated as Artificial Water Bodies, and there is a lack of clarity regarding the most appropriate objectives to set for these.

The Habitats Directive (HD) requires European Member States to attain Favourable Conservation Status for certain specified Habitats and Species listed in Annexes using a combination of Protected Areas (Special Areas of Conservation – SACs) and wider territory measures.

 The Gwent Levels are not a SAC and no freshwater Annex I habitats are known to occur in them. The River Usk SAC will need to be crossed by the M4 relief road but this is outside the scope of this document.

The Wildlife and Countryside Act 1981 (as amended) is the main legal mechanism for nature conservation in Wales. In the context of the Gwent Levels, the key powers are (i) the designation and management of protected sites, termed Sites of Special Scientific Interest (SSSIs) and (ii) strict protection of certain threatened species. SSSIs are designated and managed based on named habitat and / or species features which are protected in law. In many cases targets are set to determine whether management is favourable following guidelines set by the Joint Nature Conservation Committee (JNCC).

Approved Version – 12 December 2016

 The Gwent Levels consists of seven SSSIs in a contiguous belt broken only by the Usk estuary.  The SSSIs are designated for a wide range of features (Appendix 1). These vary in their dependency on water and their sensitivity to poor water quality.

The Environmental Permitting Regulations (England and Wales) 2010 is UK legislation that aims to prevent facilities/activities from causing harm to the environment or human health. The environmental permitting regime requires operators to obtain permits for some activities in order to protect the environment so that statutory and Government policy environmental targets are achieved and to encourage regulators to promote best practice in the operation of activities.

Hydrology of the Levels

The Gwent Levels are poorly connected to the Welsh river network and lie in one of the driest parts of Wales. As a consequence, much of the water they receive is in the winter, with very limited summer recharge. Most of this comes from precipitation that falls on the Levels themselves, rather than from upstream areas with higher rainfall. This means that water levels can fall markedly, especially in a dry summer, and water quality tends to deteriorate over the course of the summer as solutes become concentrated. This feature of the Levels needs to be taken into account in any consenting, because discharges that may have no effect in winter could be much more significant in summer.

Any permit to discharge rainfall related surface run-off has a rainfall related emission limit and not a daily maximum volume limit, therefore volumes being discharged from the construction site should emulate natural rainfall levels.

Due to the absence of flow in summer, NRW’s advice is that the design of any discharge needs to either (i) meet or exceed water quality standards in Table 2 or (ii) if these standards are already met, discharge water of equivalent quality to measured values in order to avoid deterioration.

Available Environmental Standards and their Application to the Levels

Three different sets of environmental standards exist, which vary substantially in the way they have been drafted. These are dealt with in turn.

WFD Standards Water Framework Directive standards have been developed to measure the impact of specific identified pressures as the deviation from a reference condition. These have been developed using large datasets across the UK, and subject to UK consultation and a European level peer review process termed inter-calibration. WFD standards for the second River Basin Management Planning cycle (2015-2021) are published in the ‘Water Framework Directive (Standards and Classification) Directions (England and Wales) 2015’ and the methods published on the UKTAG website, www.wfduk.org.

Under WFD, an assessment must be made to identify if a project may cause a deterioration of an element or compromise achieving the environmental objectives. If there is a risk of deterioration or that the objectives are compromised then the project may only proceed if the criteria under Article 4(7), 4(8) and 4(9) are satisfied. This would require a derogation

Approved Version – 12 December 2016 assessment to be undertaken by the relevant consenting body, supported by information provided by the applicant, NRW and other sources.

A key difficulty with the application of WFD standards to the Gwent Levels is the relevance of different water quality standards to ditch and reen systems. UK WFD standards in freshwater are designed to apply to one of two environments: rivers or lakes. Both types of environment are naturally much better oxygenated than ditches due to the greater amount of water movement, and this means that the organisms that inhabit them are accordingly much more sensitive to low oxygen levels than ditch communities.  In NRW’s view therefore, WFD biological and chemical standards for Good Status do not automatically apply to the Levels.  However, if available monitoring data indicate that they can be applied with reasonable effectiveness1, then we will use these standards.

In contrast, thresholds for toxic substances are more or less universal across different freshwater environments. It is anticipated that usage of pesticides will be low risk during construction, but due to the extensive contaminated land around Llanwern, monitoring of metal concentrations is strongly recommended.  NRW recommends that WFD standards for metals and pesticides are applied as being the best currently available standards for these substances.

SSSI Ditch Standards The Joint Nature Conservation Committee (JNCC), in collaboration with the statutory UK conservation agencies, produced monitoring guidance for ditches and canals (JNCC, 2005) that sets out a standard approach to assessment of condition. The water quality guidance in this document is often imprecise and some of it relates to General Quality Assessment (GQA) standards that predated the Water Framework Directive. However, NRW will follow the general principle in the ditch CSM guidance that ditches in favourable condition should have clear, unpolluted water.

NRW has therefore interpreted the JNCC ditch guidance to mean that water quality should meet current water quality standards and therefore the older General Quality Assessment (GQA) approach have been replaced by relevant WFD targets where applicable.

In addition, CCW produced an internal set of SSSI trigger levels which were used for casework in the Gwent Levels. These are intended to be used as a means of triggering action if a one-off concentration is breached: they are not intended as measurements of favourable condition.

The list of determinands and their target values have been reviewed in combination with the current WFD standards and other relevant evidence, JNCC guidance, risks from road runoff and available monitoring data to provide final advice. In general these were found to be insufficiently protective of water quality in the light of current environmental standards. Some similar determinands were also rationalised to improve efficiency. The proposed changes are summarised below:

1 ‘Reasonable effectiveness’ means that when applied to the Gwent Levels, an environmental standard gives a classification result that, in NRW’s opinion, reflects the overall environmental condition of the relevant water body taking into account the pressure being measured by that standard. Approved Version – 12 December 2016 Table 1. Summary of changes to SSSI determinand trigger levels

SSSI Determinand Modification pH Minor changes to align with WFD standard Conductivity Tightened to align with WFD salinity standard Replaced with a Secchi disc measure to align with Total Suspended Solids JNCC guidance and which is cheaper and simpler to monitor. Biological Oxygen Demand Tightened to align with WFD standard Level unchanged, but linked to P standard to reflect Total Oxidised Nitrogen (TON) potential varying nutrient dynamics. Nitrate No longer used (included within TON). Nitrite No longer used (included within TON). Ammoniacal N Tightened to align with WFD standard. Tightened to align with WFD standard; also linked to Orthophosphate TON. Sulphates Unchanged. Chloride Unchanged. Calcium No longer used (include within Conductivity). Zinc Tightened to align with WFD standard. Lead Tightened to align with WFD standard. Cadmium Tightened to align with WFD standard. Nickel Tightened to align with WFD standard. Replaced with PAH standard that reflects current best Petrochemicals practice. Tightened based on advice from water quality Oil and Grease specialists. Dissolved Oxygen Not used due to large natural variation.

The above approach is designed for habitats and not tailored to individual species. We expect that this approach will be sufficient to support the needs of the wide range of water dependant species features on the Levels, and have consulted with individual species specialists internally to confirm this. In most cases we expect that relevant available evidence will be limited.

Differing objectives In some cases, two different objectives may apply for the same determinand, due to different approaches taken by different guidance/directions, or due to different sensitivities of SSSI features. In this case both objectives may be applied under different assessments. However, revision of SSSI trigger levels to better align with WFD standards has greatly reduced the probability of this occurring.

Balance of Evidence and Use of the Precautionary Principle NRW is an evidence-based organisation. We will accordingly base our recommendations on evidence wherever this is possible, whether this is existing standards, published scientific evidence relating to sensitivity, or site-specific information.

However, for some of the rarer species, especially those found on the Levels, we expect that information regarding their sensitivity to poor water quality will be inadequate or entirely lacking. In this case we may need to recommend a precautionary approach.

Approved Version – 12 December 2016 We will only recommend a precautionary approach when:  Potentially sensitive: There are reasonable grounds to assume that the species is sensitive to a water quality determinand, and;  No relevant standard: There is no applicable WFD standard, and;  Geographic location: A significant proportion of the population of the potentially sensitive species is likely to be affected by the activity or discharge.

Next Steps

All of the above has been taken into account in developing NRW’s view on appropriate water quality standards for the Gwent Levels SSSIs, which is presented at Technical Appendix 2.

The endorsement, and sign-off of the Water Management Group is now required to enable these standards to be used in connection with the M4 CaN and also in relation to other development proposals of any scale likely to impact the water quality of the Gwent Levels SSSI. Adoption of these standards will enable NRW officers working within the Gwent Levels to provide consistent and evidence based advice.

There would still be an expectation that developers/applicants provide baseline water quality data relevant to their proposed development and that this would then need to be considered in relation to the principle of no deterioration.

Once agreement of this approach has been reached within NRW, it would then be communicated to those working on WG’s M4 CaN project as well as those working on other development proposals within the Gwent Levels area.

Update

NRW’s Water Management Group endorsed the approach set out in this paper during their meeting on 17 November 2016, subject to a number of amendments which have now been completed.

12 December 2016

Approved Version – 12 December 2016

Technical Appendix 1 SSSI Features per Gwent Levels SSSI

Redwick & Llandevenny & Redwick

Gwent Levels Gwent

Rumney & Peterstone & Rumney

SSSI Name Wetlands Newport

Nash & Goldcliff

Gwent Levels Gwent Levels Gwent

Gwent Levels Gwent Levels Gwent Levels Gwent

& Undy Magor Marsh Magor

-

St Brides

Whitson

Feature

– –

– – –

Standing Water (habitat)         Swamp   Marshy grassland  Independently qualifying plant species Potamogeton trichoides (water plant – hairlike pondweed)        Wolffia arrhiza (water plant – rootless duckweed)        Carex elata (wetland plant) 

Bagous tubulus (weevil  Bombus sylvarum (shrill carder bee)     Coenagrion pulchellum (variable damselfly)    Hydaticus transversalis (water beetle)       Hydrophilus piceus (water beetle)        Laccornis oblongus (water beetle)  Limnoxenus niger (water beetle)   Odontomyia ornata (fly)         Plateumaris braccata (beetle)   Anas clypeata (bird - shoveler)  Limosa (bird - curlew)  Cettia cetti (bird - Cetti’s warbler)  Tringa totanus (bird - redshank)  Vanellus vanellus (bird - lapwing) 

Recurvirostra avosetta (bird - avocet)  Panurus biarmicus (bird - bearded tit)  Rallus rallus (bird - water rail)  Breeding bird assemblage of lowland open waters and their margins   Fen invertebrate assemblage  Grazing levels invertebrate assemblage        Rare Aquatic Plant Assemblage       

Habitat (F = freshwater; freshwater; = (F Habitat

Likely

water dependant; T = T = water dependant;

WD = terrestrial but but terrestrial WD =

Terrestrial and not not and Terrestrial

poor water water quality poor

water water dependant)

to be affected by by affected be to

Feature

Standing Water (habitat) F Y Swamp F Y Marshy grassland WD ? Potamogeton trichoides (water plant – hairlike pondweed) F Y Wolffia arrhiza (water plant – rootless duckweed) F Y Carex elata (wetland plant) WD N Bagous tubulus (weevil) WD ? Bombus sylvarum (shrill carder bee) T N Coenagrion pulchellum (variable damselfly) F Y Hydaticus transversalis (water beetle) F Y Hydrophilus piceus (water beetle) F Y Laccornis oblongus (water beetle) F Y Limnoxenus niger (water beetle) F Y Odontomyia ornata (fly) T? ? Plateumaris braccata (beetle) T? ? Anas clypeata (bird - shoveler) F ? Limosa limosa (bird - curlew) WD Y

Cettia cetti (bird - Cetti’s warbler) WD ? Tringa totanus (bird - redshank) WD ? Vanellus vanellus (bird - lapwing) WD ? Recurvirostra avosetta (bird - avocet) F ? Panurus biarmicus (bird - bearded tit) WD N Rallus rallus (bird - water rail) F ? Breeding bird assemblage of lowland open waters and their margins Mixed Mixed Fen invertebrate assemblage Mixed Mixed Grazing levels invertebrate assemblage Mixed Mixed Rare Aquatic Plant Assemblage F Y

Technical Appendix 2 – Water Quality Standards for the Gwent Levels

Current Reason for WFD Standard Determinand Unit Values in WG SSSI Value Reference Comments Inclusion (GES)3 sites2 Ecological Use WFD standard. 5%ile >= pH6; WFD Directions impacts of high For small datasets 6 Acid impacts pH pH Unit 7.12 - 8.20 95%ile <= 2015, Schedule 3 and low pH and 9 should be used relatively unlikely. pH9. Part 1, Table 3. events. as trigger values. Use WFD standard for WFD Directions Salinity Road salt may be a Conductivity µS cm-1 391 - 716 Mean < 1000 lakes for routine work, 2015, Schedule 3 standard source of pollution. and 1500 as trigger. Part 1, Table 11. Specific measure of 300 (maximum SSSI trigger Road salt may be a Chloride mg l-1 14.8 - 46.8 None road salt allowable). levels.4 source of pollution. pollution Use visual check – bed of ditch / reen should be visible at Water clarity is least with Secchi disc. Smothering of JNCC Ditch important in ditches. Secchi Water clarity plants and No data None monitoring Replaces depth If this is not possible, animals guidance 2005. suspended solids 20mg l-1 or a one-off target. trigger level of 60 mg l-1 suspended solids may be used.5 Biochemical High oxygen 90%ile = 6.77 Use WFD Moderate WFD Directions BOD is likely to be 90%ile <5 Oxygen demand mg l-1 (all data or better standard. (no 2015, Schedule 3 naturally higher in (Good) Demand (BOD) results in combined) deterioration if H-G). Part 1, Table 2. the Levels, but

2 Means unless stated. 3 Many WFD standards are not simple and the detail of calculating them cannot be conveyed in full in a table such as this one. Full details of all of the standards here including calculation tools and literature explaining their derivation are published on www.wfduk.org 4 WHO standard for chloride in drinking water = 250 mg l-1. British Columbia recommended guidelines for chloride in freshwaters: Max = 600 mg l-1 (Conductivity > 2133 µS cm-1) and 30-day average <150 mg l-1. 5 20 mg l-1 was previously used for the Freshwater Fish Directive. It is included here because a numerical target was requested, but visual checks are recommended as being both simpler and more ecologically relevant.

Current Reason for WFD Standard Determinand Unit Values in WG SSSI Value Reference Comments Inclusion (GES)3 sites2 dissolved 90%ile <6.5 diffuse pollution is oxygen sags (Moderate) widespread. 90%ile <0.6 Use WFD Moderate WFD Directions Total ammonia (Good) Widespread chronic Toxic effects mg l-1 90%ile = 0.97 or better standard (no 2015, Schedule 3 as N 90%ile <1.1 failures of GES. deterioration if H-G) Part 1, Table 7. (Moderate) Key plant Site-specific: WFD Directions Ortho- nutrient, Geomean = Use WFD standard if Widespread chronic µg l-1 Generally G:M 2015, Schedule 3 phosphate causes 40.1 - 1008 possible. failures of GES. boundary c 90. Part 1, Table 5. eutrophication Either or both of: (1) Key plant Nutrient pattern is meets ortho-P Total Oxidised nutrient, NVZ criterion for generally that either mg l-1 0.11 - 8.40 None. standard above, or (2) Nitrogen as N causes lakes. N or P are likely to Annual Mean TN < 2. eutrophication be limiting. ** Potential for Scientific literature toxic effects at >300 SSSI trigger SSSI trigger indicates variable Sulphate mg l-1 high level. levels. toxicity depending concentrations on water hardness. WFD Directions All WG sample Zinc 10.9 + ambient Toxic pollutant µg l-1 1.44 - 6.98 Use WFD standard. 2015, Schedule points currently (bioavailable) background6 3, Part 2, Table 1. pass. WFD Directions All WG sample Copper Toxic pollutant µg l-1 1.23 - 4.497 1.00 (AM) Use WFD standard. 2015, Schedule points currently (bioavailable) 3, Part 2, Table 1. pass. Lead and its WFD Directions 1.3 (AM); 1 WG sample point compounds Toxic pollutant µg l-1 0.06 - 1.53 Use WFD standard 2015, Schedule 14 (MAC). fails. (dissolved) 3, Part 3, Table 1.

6 Reference background levels are available at http://www.wfduk.org/resources%20/estimation-background-reference-concentrations-metals-uk-freshwaters. A value of 5 µg l-1 (10%ile for the River Usk catchment) is recommended. 7 These are dissolved Cu values, but due to the high alkalinity, when run through the WFD M-BAT bioavailability tool, all points nevertheless pass the standard.

Current Reason for WFD Standard Determinand Unit Values in WG SSSI Value Reference Comments Inclusion (GES)3 sites2 Cadmium and WFD Directions All WG sample 0.15 (AM); its compounds Toxic pollutant µg l-1 0.00 - 0.13 Use WFD standard 2015, Schedule points currently 0.9 (MAC). (dissolved) 3, Part 3, Table 1. pass. Nickel and its WFD Directions All WG sample 4 (AM); compounds Toxic pollutant µg l-1 0.84 - 2.90 Use WFD standard 2015, Schedule points currently 34 (MAC). (bioavailable) 3, Part 3, Table 1. pass. Polycyclic 1.7 x 10-4 WFD Directions Aromatic 3 WG sample points Toxic pollutant µg l-1 0.00 – 0.46 (AM); Use WFD Standard 2015, Schedule Hydrocarbons fail. 0.27 (MAC). 3, Part 3, Table 1. (PAHs)8 None visible. SSSI Trigger 1 WG sample point Oil and Grease Toxic Pollutant mg l-1 0.00 – 3.56 None 1 mg l-1 (MAC) Levels (adjusted) fails. Pesticides and other These should be Hazardous and Generally WFD Directions included subject to Priority Toxic Pollutant Various below limit of Various Use WFD standard. 2015 the results of a risk Substances detection. assessment. identified under WFD

8 The standard refers to the sum of five different PAHs: benzo (a) pyrene which is the commonest PAH is typically used as a marker for others.

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