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1 Company Document NNB-209-REP Version 1.0 NNB GENERATION COMPANY LTD ALDHURST FARM HABITAT CREATION SCHEME ABSTRACTION LICENCE APPLICATION Version 1.0 Date of Issue 26/05/2015 Document No. NNB-209-REP Status Issued Next Review Date 26/11/2015 Owner & Approver Environmental Compliance Manager Consents Manager Technical Reviewer Environmental Compliance Specialist Author Principal Contractor 2014 Published in the United Kingdom by NNB Generation Company Limited (NNB GenCo), 90 Whitfield Street - London, W1T 4EZ. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, including photocopying and recording, without the written permission of the copyright holder NNB GenCo, application for which should be addressed to the publisher. Such written permission must also be obtained before any part of this publication is stored in a retrieval system of any nature. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 1 of16

2 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP-000XXX Version 0.1 Requests for copies of this document should be referred to NNB Generation Company Limited (NNB GenCo), 90 Whitfield Street - London, W1T 4EZ. The electronic copy is the current issue and printing renders this document uncontrolled APPROVAL SIGN-OFF: ALDHURST FARM ABSTRACTION LICENSE APPLICATION Originated by: Title: Principal Consultant Date:18/05/2015 Reviewed by: Title Consents Manager Title: Environmental Compliance Specialist Date: 21/05/2015 Approved by: Title: Environmental Compliance Manager Date: 26/05/2015 DOCUMENT CONTROL Version Purpose Amendment By Date 0.1 For Review 19/05/ Issued 26/05/52015 NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 2 of 16

3 TABLE OF CONTENTS NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version INTRODUCTION Purpose of document Structure of document Existing on-site Abstraction Licence 7/35/03/*G/ Requirement for Abstraction Licence Application Pre-application discussions FORM WR174 SUPLEMENTARY INFORMATION Form Contents Question 4 Entitlement to apply Question 6.2 For each of the purposes you have listed in 6.1 (except spray/trickle irrigation) please list how much water you feel you will need to abstract Question 10: Other considerations Question 11 Checklist... 8 APPENDIX A APPLICATION FORMS... 9 APPENDIX B ENVIRONMENTAL ASSESSMENT APPENDIX C PROOF OF LAND OWNERSHIP APPENDIX D PUMP TEST REPORT AND ABSTRACTION VOLUME CALCULATIONS TABLE OF FIGURES Figure 1 Operational site layout Name TABLE OF TABLES Table Name 1.1 Summary of Environment Agency Pre-Application response 2.1 Location of answers to Form WR174 NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 3 of 16

4 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version INTRODUCTION 1.1 Purpose of document This document, and its Appendices, contains the information necessary to satisfy the requirements of the Environment Agency s (EA) application process for a new groundwater abstraction licence at Aldhurst Farm Habitat Creation Scheme being submitted by NNB Generation Company (SZC) Ltd (company registration number ),. The following EA application forms have been completed as part of this application and are included at Appendix A: Form WR173: Water abstraction or impoundment application for a full, transfer or impounding licence; and Form WR174: Water abstraction and impoundment application for a full or transfer licence. 1.2 Structure of document The completed application forms can be found in Appendix A. Additional information required for form completion can be found in Section 2 to this report (Form WR174). 1.3 Existing on-site Abstraction Licence 7/35/03/*G/0049 The Aldhurst Farm site has an existing spray irrigation abstraction licence (7/34/03/*G/0049) for a series of 15 well points operated between April and September. The licence has an annual abstraction limit of 27,000 m 3 /a and a daily maximum abstraction of 900 m 3 /d. The licence was transferred from the current holder (F Barker and Co.) to NNB GenCo in April Due to their location, the well points will be decommissioned as part of the habitat creation works. The licence will be surrendered by NNB GenCo prior to issue of the new abstraction licence, on a timescale agreed with the Environment Agency. 1.4 Requirement for Abstraction Licence Application The proposed Aldhurst Farm Habitat Creation Scheme comprises the creation of four groundwaterfed basins, and associated reedbed habitat, along the course of the Leiston Drain, and its tributary the Aldhurst Valley Stream (see Figure 1). This site lies immediately upstream of Sizewell Marshes Site of Special Scientific Interest (SSSI). The basins will be fed by the local groundwater table in the Sands and Gravels aquifer. Each basin will have an outflow structure, comprised of a concrete pipe fitted with stop logs. Flows at the site will only be from the basins to the streams, there will be no inflow points from the streams to the basins. Figure 1 shows the approximate locations of these structures, although their final location will be determined on site as part of the construction works (primarily to avoid disturbance of water voles during construction). There will be an additional connection between Basin A and C to provide flexibility in terms of management of basin water levels and flows. Each outfall structure will be of the same design. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 4 of 16

5 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version 1.0 Construction of the basins and their water level management will result in change to the groundwater and surface water regime, but this change has been assessed to constitute no significant effects ; as set out in the Environmental Assessment (Appendix B). The proposed basin water levels are below existing groundwater levels (e.g. 0.2 m below the average summer groundwater level) and would therefore result in a localised lowering of groundwater levels. Under most conditions the basins will outflow to the Aldhurst Valley Stream and Leiston Drain. This is unlikely to result in a significant change in flows in the Leiston Drain downstream of the site, as this will be balanced by a decrease in groundwater discharge to the stream. The creation of wet reedbed and open water habitat in the basins has the potential to result in additional evapo-transpirative losses from the site potentially leading to a reduction in flow in the Leiston Drain. Water balance calculations (see Appendix D) indicate a potential loss of up to 3 l/s, but more typically 1 to 2 l/s during the summer. The implication is that flow in the Drain, downstream of Lover s Lane could potentially fall below 11 l/s under severe drought conditions. The Environment Agency has identified that flow in the stream should not fall below 11 l/s. Under this scenario, it is proposed that flow in the Leiston Drain would be supported by a licensed groundwater abstraction (the subject of this application). Stream support would be implemented if flows in Leiston Drain at Lovers Lane fell below 11 l/s. The abstracted water will be fed to the Leiston Drain and discharged downstream of the Wastewater Treatment Works (WwTW). However, it is expected that for most years stream support will not be required. In order to construct the new habitat, the well points and pump house serving the existing spray irrigation abstraction (licensed under 7/35/03/*G/0049) will be decommissioned due to their position within the basin area. A new borehole (BH1) is proposed to be used for abstraction and has been drilled outside of the wet reedbed and open water habitat (National Grid Reference TM ) with the purpose of augmenting flows in the Leiston Drain at times when flows fall below 11 l/s. The spray irrigation abstraction licence allows the abstraction of 27,000 m 3 /a. If this quantity is transferred to the new borehole this would allow an average stream support discharge of 3 l/s (a discharge higher than the maximum evaporative loss) for a period of about 100 days. As noted above, the existing licence will be surrendered by NNB GenCo prior to issue of the new abstraction licence, on a timescale agreed with the Environment Agency. 1.5 Pre-application discussions NNB GenCo submitted a pre-application enquiry to the EA, and has supplied information in line with the guidance in Environment Agency Form WR48: Water Abstraction or Impoundment Preliminary Application Form. The formal response 1 from the EA is summarised in Table 1.1. Table 1.1 Summary of Environment Agency Pre-Application response Subject NPS Reference Number Summary of response Abstraction Variation NPS/WR/ Variation of - Any licence granted will be time limited to 31 March There will be an application fee of 135, to be provided with the 1 Environment Agency Water Resources pre-application response (ref NPS/WR/ NPS/WR/ NPS/WR/017467), received from Robert Davies, Permitting Officer, National Permitting Service, 22/12/2014 NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 5 of 16

6 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version 1.0 Subject NPS Reference Number Summary of response 7/35/03/*G/0049 F Barker & Co application. Advertising may cost an additional 100 to be invoiced by the Environment Agency separate to the application. - Application should be made using forms WR173 and WR174 Additional discussion with the EA advised that a new licence application, rather than an application to vary the existing licence, would be preferable. Figure 1 Operational site layout NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 6 of 16

7 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version FORM WR174 SUPLEMENTARY INFORMATION 2.1 Form Contents Table 2.1 Location of answers to Form WR174 Question Location of response 1 In Form 2 In Form 3 In Form 4 For proof of land ownership see Appendix C. 5 N/A no request to change time limits 6 For further detail on Question 6.2 see Section N/A licence is not for spray irrigation 8 In Form 9 In Form 10 For further detail on Question 10 see Section For further detail on Question 11 see Section Question 4 Entitlement to apply Proof of land ownership can be found in Appendix C. 2.3 Question 6.2 For each of the purposes you have listed in 6.1 (except spray/trickle irrigation) please list how much water you feel you will need to abstract. Question 6.2 asks for maximum abstraction quantities, the text in Section describes how these have been calculated. 2.4 Question 10: Other considerations Question 10.5: How have you calculated the quantities you need to abstract? Enhanced evapo-transpiration from the four groundwater basins will result in an additional water loss of 1 to 2 l/s during the summer and a potential reduction in flow in the Leiston Drain. The implication is that flow in the Leiston Drain, downstream of Lover s Lane could, in extreme circumstances, fall below 11 l/s. The EA has identified that flow in the stream should not fall below this level. Under this scenario, flow in the Leiston Drain would be supported by discharge from the proposed groundwater abstraction. For the calculations of evapo-transpirative loss see Appendix D. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 7 of 16

8 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version 1.0 The existing licence allows an abstraction quantity of 27,000m 3 /a, with a maximum daily quantity of 900 m 3 /d (equivalent to 10.4 l/s) for spray irrigation purposes, this licence is to be surrendered once the well points are decommissioned. This application is therefore being submitted to enable this quantity of water to be abstracted for stream augmentation purposes under the new licence via the newly installed borehole BH1. As proposed, this would allow an average stream support discharge of 3 l/s (approximately equivalent to the maximum evaporative loss under drought conditions) for a period of about 100 days. Retaining the existing maximum daily licensed quantity would provide flexibility for a higher level of abstraction in the event of extreme drought conditions. Pump testing (see Appendix D: Borehole and Pump Test Analysis Report) of the new abstraction borehole has indicated that abstraction of the existing licensed quantities is feasible from this borehole with no significant effect on the Leiston Drain or the downstream SSSI. It should be noted that flow in the Leiston Drain at Lover s Lane is also supported by compensation from the Leiston Public Water Supply licence which requires that Essex & Suffolk Water discharge up to 570 m 3 /d (6.6 l/s) to the Leiston Drain when directed to do so by the Environment Agency (such directions may be received during the period May October). Additionally the average discharge from the Leiston WwTW in summer months (data from ) is around 12 l/s Question 10.9 Do you have a consent from the Environment Agency to discharge water from this site? The discharge of water for stream augmentation is the purpose of this licence and no separate discharge permit is required. 2.5 Question 11 Checklist Figure 2 fulfils the stipulated requirements for a figure in this checklist. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 8 of 16

9 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version 1.0 APPENDIX A APPLICATION FORMS NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 9 of 16

10 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version 1.0 NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 10 of 16

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22 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version 1.0 APPENDIX B ENVIRONMENTAL ASSESSMENT NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 11 of 16

23 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version 1.0 NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 12 of 16

24 Company Document NNB-209-REP Version 1.0 NNB GENERATION COMPANY LTD ALDHURST FARM HABITAT CREATION SCHEME WATER RESOURCES ABSTRACTION LICENCE APPLICATION: ENVIRONMENTAL ASSESSMENT Version 1.0 Date of Issue 26/05/2015 Document No. NNB-209-REP Status Issued Next Review Date 26/11/2015 Owner & Approver Environmental Compliance Manager Technical Reviewer Planning Manager Environmental Compliance Specialist Design and Non-Radiological Technical Specialist Author Principal Consultant 2015 Published in the United Kingdom by NNB Generation Company Limited (NNB GenCo), 90 Whitfield Street - London, W1T 4EZ. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, including photocopying and recording, without the written permission of the copyright holder NNB GenCo, application for which should be addressed to the publisher. Such written permission must also be obtained before any part of this publication is stored in a retrieval system of any nature. Requests for copies of this document should be referred to NNB Generation Company Limited (NNB GenCo), 90 Whitfield Street - London, W1T 4EZ. The electronic copy is the current issue and printing renders this document uncontrolled NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 1 of 17

25 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT APPROVAL SIGN-OFF: ALDHURST FARM HABITAT CREATION SCHEME WATER RESOURCES ABSTRACTION LICENCE APPLICATION: ENVIRONMENTAL ASSESSMENT Originated by: Title: Principal Consultant, Water Management Date: 18/05/2015 Reviewed by: Title: Planning Manager Title: Environmental Compliance Specialist Electronically Reviewed Date: 20/05/2015 Title: Design and Non-Radiological Technical Specialist Approved by: Title: Environmental Compliance Manager Electronically Approved Date: 27/05/2015 DOCUMENT CONTROL Version Purpose Amendment By Date 0.1 For Review 18/05/ Issued 26/05/2015 NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 2 of 17

26 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT TABLE OF CONTENTS 1 INTRODUCTION Purpose of document Requirement for Environmental Assessment Structure of document HYDROLOGICAL/HYDROGEOLOGICAL IMPACT ASSESSMENT Introduction Current Regime Conservation Management Summary APPENDIX A WFD ASSESSMENT APPENDIX B HABITAT REGULATIONS ASSESSMENT TABLE OF FIGURES Figure Name 1 Operational site layout 2 Schematic Groundwater and Surface Water Regime 3 Flow Accretion Survey and Channel Bed Elevation from Abbey Road to Lover s Lane 4 Illustration of proposed water level management depths TABLE OF TABLES Table Name 2.1 Estimated outflow rates for groundwater basins (in total) NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 3 of 17

27 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 4 of 17

28 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT 1 INTRODUCTION 1.1 Purpose of document This Environmental Assessment has been produced to support the Water Resources Abstraction Licences for the Aldhurst Farm Habitat Creation Scheme, which comprises the development of four groundwater fed wetland basins immediately upstream of Sizewell Marshes Site of Special Scientific Interest (SSSI) (see Figure 1). Figure 1 Operational site layout The application informs a new abstraction licence to replace spray irrigation licence 7/35/03/*G/0049 (pre app reference number NPS/WR/017406). A separate Water Resources application has been submitted to address the following: NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 5 of 17

29 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT Transfer of groundwater to surface water via outfall from gravity fed basins to Aldhurst Valley Stream (pre app reference number NPS/WR/017466) Impoundment of groundwater in basins through the use of stoplogs on basin outflow points (pre app reference number NPS/WR/017467). The requirement for abstraction of groundwater, as part of the Aldhurst Farm Habitat Creation Scheme, is due to construction of groundwater basins and their ongoing water level management resulting in change to the groundwater and surface water regime. In particular, the creation of wet reedbed and open water habitat in the basins has the potential to result in additional evapotranspirative losses from the site potentially leading to a reduction in flow in the Leiston Drain. The Environment Agency have indicated that flow in the Leiston Drain should not fall below 11 l/s, should this occur it is proposed that flow in the Leiston Drain would be supplemented by the discharge of a licensed groundwater from a newly licenced borehole abstraction. An existing abstraction for spray irrigation purposes (7/35/03/*G/0049) is located within the Aldhurst Valley. In order to construct the new habitat, the well points and pump house serving the existing abstraction will be decommissioned. It is proposed that the abstraction for stream augmentation will be taken from a new borehole (BH1) which has been drilled at a position outside of the wet reedbed and open water habitat (National Grid Reference TM ). The specific purpose of the new borehole will be to augment flows in the Leiston Drain at times when flows fall below 11 l/s. This removes the potential for an impact on groundwater levels within the footprint of the basins and below the adjacent Sizewell Marshes SSSI. The potential Environmental Effects of the new abstraction, which has been subject to investigation under a Water Resources Section 32 consent, are assessed within this document and attachments. 1.2 Requirement for Environmental Assessment NNB GenCo submitted a pre-application enquiry to the Environment Agency, in line with the guidance in Environment Agency Form WR48: Water Abstraction or Impoundment Preliminary Application Form. The formal response 1 from the Environment Agency requested an Environmental Assessment to support the Water Resources licence applications. The requested scope of this assessment can be seen in Box 1. Box 1 Scope of Environmental Assessment Water Framework Directive (WFD) Assessment We will need you to show that the scheme will not result in deterioration of the ecological status of the Leiston Drain water body, downstream of the proposal. This water body is currently classed as being moderate in status. You will need to submit a WFD assessment to show how the proposed scheme will not cause deterioration in any of the WFD quality elements and also detail any potential improvements. Habitats Directive Regulations and Countryside and Rights of Way (CRoW) Act 2000 The Aldhurst Farm site has the benefit, in terms of habitat creation, in being contiguous with the existing SSSI. However, this also means that any impacts to the existing hydrology and hydrogeology need to be carefully 1 Environment Agency Water Resources pre-application response (ref NPS/WR/ NPS/WR/ NPS/WR/017467), received from Robert Davies, Permitting Officer, National Permitting Service, 22/12/2014 NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 6 of 17

30 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT considered to ensure that there will be no damage to the SSSI through changes in groundwater table and surface water flows. A requirement for the Q95 flow of 11 litres per second to be maintained downstream of Lovers Lane will ensure that surface water flows are not significantly impacted. However, there will be a resultant reduction in groundwater flow to the site as the basins will intercept groundwater that would have otherwise discharged down gradient to the SSSI. There are areas of Fen Meadow M22 vegetation within Sizewell Marshes, downstream of Aldhurst Farm. These are potentially susceptible to changes in hydrological conditions and we will need to be confident that the proposal will not cause a reduction in the groundwater table or groundwater up flows. 1.3 Structure of document The structure of this document is as follows: Section 2: Hydrological/Hydrogeological Impact Assessment Appendix A: Water Framework Directive Assessment Appendix B: Habitats Regulation Assessment NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 7 of 17

31 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT 2 HYDROLOGICAL/HYDROGEOLOGICAL IMPACT ASSESSMENT 2.1 Introduction This section provides an assessment of the potential effects of the proposed groundwater basins and perimeter ditches on the groundwater and surface water regime of the Aldhurst Farm Site and adjacent areas. 2.2 Current Regime The current groundwater and surface water regime is illustrated on Figure 2. Groundwater flow is to the east with discharge as baseflow to the Leiston Drain. Measured flow in the Leiston Drain is typically between 10 and 60 l/s though peak/flood flows can be greater. The main components of flow in the Leiston Drain (Figure 2) are: Groundwater discharge in the lower part of the Aldhurst Valley Stream and Leiston Drain; Discharge from the Wastewater Treatment Works (WwTW) (~ 20 l/s); and Surface water run-off generated from the site and the upstream catchments of the Aldhurst Valley stream and the Leiston Drain in response to rainfall events. The flow accretion plot for the Aldhurst Valley Stream and the Leiston Drain from Abbey Road to Lover s Lane is shown on Figure 3. Groundwater levels in the valley and flows in the Drain are also influenced by the spray irrigation abstraction located within the valley (Licence no. 7/35/03/*G/0049) and by public water supply abstractions (Essex and Suffolk Water) at Coldfair Green and Leiston. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 8 of 17

32 NOTES: INTERNAL BUSINESS COLLABORATOR REFERENCE NOT APPLICABLE FOR ALL FIGURES Reproduced from Ordnance Survey map with the permission of Ordnance Survey on behalf of the controller of Her Majesty's Stationery Office Crown Copyright (2014). All Rights reserved. NNB GenCo KEY Site Boundary (Area of access) Basin Extent Wet Reedbed/Open Water Point of Abstraction Point of Discharge Basin A Basin C Basin B # Basin D REVISION DATE DRAWN CHECKED REASONS FOR REVISION/COMMENTS APPROVED BH1!( SIZEWELL C DOCUMENT: ALDHURST FARM HABITAT CREATION SCHEME APPLICATION FOR NEW ABSTRACTION LICENCE DRAWING TITLE: WR174 ABSTRACTION LICENCE APPLICATION DRAWING NO: FIGURE REVISION: DATE: DRAWN: SCALE: APR 2015 SCALE BAR L.B KM Copyright 2014 EDF Energy plc. No part of this drawing is to be reproduced without prior permission of EDF Energy DRAWING SECURITY CLASSIFICATION: PROTECTIVE MARKING REQUIRED

33 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT Figure 3 Flow Accretion Survey and Channel Bed Elevation from Abbey Road to Lover s Lane 2.3 Conservation Management Water levels in the groundwater basins will be varied by altering the stop board levels within the control structures. A typical water level management regime will be as follows: Summer: Basin water depth (wet reedbed areas) 20 to 30 cm; Winter (normal): Basin water depth (wet reedbed areas) +50 cm; Winter (maintenance): Water depth <10 cm (wet reedbed areas). The summer and winter water level regimes are illustrated in Figure 4. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 9 of 17

34 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT Figure 4 Illustration of proposed water level management depths Groundwater Basin B Schematic Ground level Winter groundwater level Summer groundwater level Min predicted groundwater level Winter basin water level Summer basin water level Min stream level Max stream level This figure illustrates that the water level in the basins will typically be below groundwater levels and above stream levels (except under peak flow or flood conditions). As a result there will be an outflow from the basins under most conditions. The possible exception is under severe drought and fully licensed abstraction conditions, when water levels in the basins may be sufficiently low that outflows cease. The hydrological regime for the site following completion of the groundwater basins is presented in Figure 2. The surface water outflow from the basins will result in a reduction in groundwater discharge (baseflow) to the Aldhurst Valley Stream and Leiston Drain within the valley, however any reduction in baseflow in the Leiston Drain will be compensated by the outflow from the basins and therefore no change to flows and water levels is expected. In terms of seasonality of impact, the likelihood is that in a normal year there may be a small net increase in summer flows and a small net decrease in winter flows in the Leiston Drain. The typical outflow from the four basins is estimated to be about 6 l/s (~500 m 3 /d) in total in the summer increasing to 15 l/s (~1300 m 3 /d) in the winter. These outflows are comparable to groundwater discharge to the Leiston Drain. These flows have been estimated using the Depuit Thiem equation (Table 2.1). NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 10 of 17

35 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT Table 2.1 Estimated outflow rates for groundwater basins (in total) Hydraulic conductivity m/d 1 Lowering of groundwater level m Outflow rate l/s (m 3 /d) (summer) 3 (~300) (summer) 6 (~550) (winter) 8 (~700) (winter) 16 (~1400) 1 Values of hydraulic conductivity based on the Environment Agency regional groundwater flow model (typical value 5m/d) and permeability testing in the Sizewell area (typical value 10 m/d). Enhanced evapo-transpiration from the four groundwater basins will result in an additional water loss of 1 to 2 l/s during the summer and a potential reduction in flow in the Leiston Drain. The implication is that the enhanced evapo-transpiration losses, resulting from the proposed scheme, could impact flow in the Drain downstream of Lover s Lane which, in extreme circumstances, could cause flow to fall below 11 l/s. The Environment Agency has identified that flow in the stream should not fall below this level. Should this scenario arise, it is proposed that flow in the Drain would be supported through the discharge of abstracted groundwaters from the newly constructed borehole. It is however worth noting that the average discharge from the Leiston WwTW in summer months (data from ) is around 12 l/s. This discharge clearly exceeds the minimum required flow of 11 l/s (~950 m 3 /d), the implication therefore being that flow augmentation in the Leiston Drain from the discharge of grondwaters is unlikely to be required, other than potentially in severe or sustained drought conditions. Additionally, it should be noted that flow in the Leiston Drain at Lover s Lane is also supported by compensation from the Leiston Public Water Supply licence which requires that Essex & Suffolk Water discharge up to 570 m 3 /d (6.6 l/s) to the Leiston Drain when directed to do so by the Environment Agency (such directions may be received during the period May October). A groundwater source investigation was undertaken under Water Resources (WR) Section 32(3) consent to drill and test the newly installed abstraction borehole (BH1). The details of the investigation and testing are documented in the Pump Test Report (Appendix D of Licence Application). The step test determined that BH1 was able to provide sufficient yield for the constant rate test to be undertaken at the planned abstraction rate of 10.4 l/s. A three day constant rate test was undertaken and the maximum groundwater drawdown recorded at the pumped well was 3.9 m. The pump test analysis indicated that the Crag aquifer has high transmissivity, around 800 m 2 /day. Groundwater level monitoring at boreholes AF1 (Crag) and AF2 (sands) (located 264 and 192 m respectively from the abstraction) recorded a maximum drawdown of 0.05 m during testing indicating minimal impact on groundwater levels in the immediate vicinity of the abstraction. Surface water monitoring in the Leiston Drain showed only a small change in stage and flow during the constant rate pump test as a result of the addition of 10.4 l/sec discharge from the abstraction borehole. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 11 of 17

36 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT The effect of the abstraction on groundwater levels in borehole BH1 located close to the western edge of Sizewell Marshes SSSI was also monitored and the change in water level was less than 0.02m. Grassland (MG10a) is present within the SSSI immediately to the east of Lover s Lane. Abstraction is unlikely to have a significant effect on this habitat which is likely to be relatively resilient to such changes in water level. Further to the east (approximately 250 m from the edge of Basin B and around 750 m from the abstraction point) Fen Meadow (M22b) is present which is more sensitive to changes in water level. The pump test analysis indicated that at this location there would be a groundwater level change of <0.01 m for abstraction rates of 2 l/sec for up to 100 days duration based on calculations presented in the Pump Test Report (Appendix D of Licence Application) and therefore would not affect the M22b community. The existing abstraction source has a licensed annual abstraction quantity of 27,000 m 3 /a. If the new borehole is licensed for the same quantity this would allow an average stream support discharge of 3 l/s (approximately equivalent to the maximum evaporative loss under drought conditions) for a period of about 100 days. Pump test analysis has indicated that the lowering in groundwater levels below M22b would be less than 0.01m and therefore would not affect this community. It is also noted that the new abstraction borehole has been located further away from the SSSI than the existing abstraction. Stream support from the newly constructed borehole would be implemented if flows in Leiston Drain at Lover s Lane fell below 11 l/s. In Figure 2, the above points have been represented as schematics of the flow hydrographs for average and dry years. In summary, the conclusion is that the proposed basin water levels and associated compensatory stream support, if required, will not result in a net change in the flow regime for the Leiston Drain and the surrounding area. 2.4 Summary Creation of wet reedbed and open water habitat in the proposed habitat creation scheme at Aldhurst Farm has the potential to result in additional evapo-transpirative losses from the site potentially leading to a reduction in flow in the Leiston Drain. The Environment Agency has indicated that flow in the Leiston Drain should not fall below 11 l/s. Should this occur, it is proposed that flow in the Drain would be supported by a licensed groundwater abstraction. An existing abstraction for spray irrigation purposes (7/35/03/*G/0049) is located within the Aldhurst Valley. In order the construct the new habitat, the well points and pump house serving the existing abstraction will be decommissioned. A new borehole (BH1) is proposed to be used for abstraction with the purpose of augmenting flows in the Leiston Drain in the unlikely event that flows fall below 11 l/s. It is important to note that the newly licenced abstraction would only come into operation once the existing spray irrigation wells are decommissioned. Pump testing of the new abstraction borehole (BH1) has indicated that that there would be a groundwater level change of <0.01 m within 750 m of the abstraction well at the SSSI for abstraction rates of 2 l/sec for up to 100 days duration, indicating no significant impact on water levels within the SSSI. A change to groundwater levels at the SSSI (750 m from abstraction) of up to 0.1m was calculated for pumping rates of 10.4 l/sec (proposed licensed abstraction rate) for duration of 30 days, No drawdown is calculated 750 m from the abstraction at a pumping rate of 10.4 l/s in the first 10 days of pumping. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 12 of 17

37 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT The existing abstraction source has a licensed abstraction quantity of 27,000 m 3 /a. If the new abstraction was licensed with the same quantity, as proposed, this would allow an average stream support discharge of 3 l/s (approximately equivalent to the maximum evaporative loss under drought conditions) for a period of about 100 days. In reality stream support may not be required, other than potentially in severe or sustained drought conditions, therefore the predicted abstraction quantities and impacts represent a conservative assessment. On this basis it is concluded that there would be no significant effects on the Leiston Drain, WFD status or Sizewell Marshes SSSI (or any downstream European site). NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 13 of 17

38 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 14 of 17

39 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT APPENDIX A WFD ASSESSMENT NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 15 of 17

40 ALDHURST FARM HABITAT CREATION SCHEME WFD ASSESSMENT NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 1 of 44

41 NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 2 of 44

42 TABLE OF CONTENTS 1 INTRODUCTION Purpose of this WFD assessment Structure of the document CONTEXT LEGISLATIVE BACKGROUND Water Framework Directive (WFD) (2000/60/EC) ASSESSMENT METHODOLOGY Stage 1 WFD water body review Stage 2 Assessment of the scheme Stage 3 Mitigation discussions BASELINE WATER ENVIRONMENT Surface Water body Review Groundwater body Review Further baseline characterisations RESULTS WFD ASSESSMENT Introduction Consideration of the scheme Leiston Beck WFD Unit (ID: GB ) Biological Elements Hydromorphological Elements Chemical Status WFD Mitigation Measures Waveney and East Suffolk Chalk & Crag WFD Unit (ID: GB40501G400600) Chemical Elements Quantitative Elements Overall WFD Status CONCLUSION REFERENCES NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 3 of 44

43 LIST OF FIGURES Figure 1.1 Site location Figure 3.1 Basis for WFD Ecological Classification (taken from EA, 2011a) Figure 3.2 Defining Ecological Potential (taken from EA, 2014b) Figure 5.1 Surface Water catchment boundary of the Leiston Beck (Cycle 2) WFD water body LIST OF TABLES Table 3.1 Table 3.2 Table 5.1 Table 5.2 WFD Quality Element supporting WFD Ecological Classification Quality Elements for River WFD bodies Annual Updates to Cycle water body (Leiston Beck and Minsmere Old River) Details for the Leiston Beck Water Body Table 5.3 Details for the Waveney and East Suffolk Chalk & Crag Groundwater Body, taken from 2009 RBMP Table 5.4 Details for the Waveney and East Suffolk Chalk & Crag Groundwater Body, taken from draft 2015 RBMP (EA 2014b) Table 6.1 Details of scheme components relevant to this assessment Table 6.2 Assessment of impact of proposed scheme on biological elements Table 6.3 Assessment of impact of proposed scheme on hydromorphological elements Table 6.4 Assessment of impact of proposed scheme on chemical elements Table 6.5 Assessment of impact of proposed scheme on those mitigation measures listed in the 2009 RBMP. Table 6.6 Assessment of impact of proposed scheme on groundwater chemical elements Table 6.7 Assessment of impact of proposed scheme on groundwater quantitative elements NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 4 of 44

44 1 INTRODUCTION EDF Energy is proposing to convert a 67ha arable farm in Leiston into wetland and terrestrial habitat. The proposed scheme centres on the creation of wetland habitat comprising lowland ditches, reedbed and open water which will occupy approximately 6 ha of low-lying land alongside two existing watercourses. Figure 1.1 shows the site location. Figure 1.1 Site Location The proposed scheme centres on the creation of lowland ditches, wet and dry reedbed and open water habitat occupying low-lying land alongside the Aldhurst Valley stream and the (upper section of) Leiston Beck. This wetland component will be set within a wider site which will comprise approximately 60ha of improved habitat. The wetland component of the proposed scheme has been designed to ensure that, with appropriate management, reedbed and lowland ditch habitats will develop that are of similar quality and composition to those within the adjacent Sizewell Marshes Site of Special Scientific Interest (SSSI), and will also support comparable invertebrate and rare vascular plant communities. The wetland would be created within groundwater basins that would be excavated to a sufficient depth to ensure that they remain permanently wet, even under drought conditions and fully licensed abstraction conditions. This is important to create NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 5 of 44

45 sustainable wetland. These wetland habitats would grade into an extensive area of drier, terrestrial habitats, comprising a mosaic of neutral and acid grassland, heathland, scrub and occasional scattered trees across the remainder of the site. 1.1 Purpose of this WFD assessment It is deemed good practice to present a WFD assessment for the purposes of: determining if components or activities associated with the Aldhurst Farm habitat creation scheme will compromise the potential for Water Framework Directive (WFD) objectives to be achieved; or result in the deterioration in the ecological status/potential of any WFD waterbodies (adjacent or hydrologically connected waterbodies) associated with the scheme site. Consultations with the Environment Agency (EA) have confirmed the requirement for a WFD assessment. 1.2 Structure of the document The structure of this WFD assessment is set out as follows: Context: Chapter 2 outlines the main elements comprising the scheme, focussing on those with the potential to interact with the water environment and WFD water body supporting elements (as defined later). Legislative Background: Chapter 3 introduces the WFD (Directive 2000/60/EC) and the available guidance that has informed the scope and methodology of the assessment. Methodology: Chapter 4 describes the methodology used for the WFD assessment. Baseline Water Environment: Chapter 5 describes the baseline water environment, providing a review of the WFD water body information and other relevant baseline characterisation data. Results: Chapter 6 contains the WFD assessment of scheme proposals. Conclusions: Chapter 7 presents the conclusions of the assessment. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 6 of 44

46 2 CONTEXT A full description of the proposed scheme is provided in the Aldhurst Farm Design Statement (AMEC 2014b) which should be read in conjunction with this WFD assessment. The overall scheme objectives are to: Create and maintain approximately 5 ha of wet reed habitat, incorporating between 20-30% open water habitat and approximately 5-15% of later succession habitats that support a characteristic assemblage of reedbed plant and animal species; Create and maintain approximately 0.8 ha of reed based tall herb fen that supports a characteristic assemblage of tall herb fen plant and animal species; Create and maintain approximately 2km of perimeter ditch habitat that supports a diverse vascular plant assemblage and a range of fauna characteristic of lowland ditch habitat; Create and maintain a mosaic of neutral and acid grassland / heathland, scrub and scattered trees transitioning from the perimeter ditches and across the wider site; Ensure no net loss of biodiversity on the Aldhurst Farm site as a result of the habitat creation scheme, and maximise the floral and faunal biodiversity of the created and retained habitats; In the longer term, enhance ecological connectivity between Aldhurst Farm and Sizewell Marshes SSSI beneath Lover s Lane; Ensure that the scheme landscape reflects the distinctive land-use and vegetation typologies of the adjacent Estate Sandlands and Coastal Levels character types; and In the longer term, open up parts of the site for quiet public recreation, in a manner that does not compromise the above habitat management objectives. Individual elements of the scheme design of particular relevance to this WFD assessment are presented in Table 6.1 within the Assessment Section below. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 7 of 44

47 3 LEGISLATIVE BACKGROUND 3.1 Water Framework Directive (WFD) (2000/60/EC) The WFD provides a mechanism by which disparate regulatory controls on human activities that have the potential to impact on the water environment may be managed effectively and consistently. In addition to inland surface and groundwater, the WFD covers transitional waters (estuaries and lagoons) and coastal waters up to one nautical mile from mean low water (baseline from which territorial waters are measured). Existing regulations that have recently been subsumed by the WFD include the Freshwater Fish Directive (78/659/EEC as consolidated in 2006) and the Dangerous Substances Directive (76/464/EEC). The Water Framework Directive (2000/60/EC) is implemented in England and Wales primarily through the Water Environment (Water Framework Directive) (England and Wales) Regulations 2003 (the Water Framework Regulations). United Kingdom (UK) surface waters have been divided into a number of discrete units termed water bodies, with meaningful typologies that relate to physical and ecological characteristics. Based upon their characteristics, these water bodies have been classified as falling into different status classes. As part of the ongoing implementation of the WFD, the EA has been given the power to apply environmental standards to individually defined WFD water bodies via the River Basin Districts Typology, Standards and Groundwater Threshold Values (Water Framework Directive) (England and Wales) Directions 2010, and the River Basin Districts Surface Water and Groundwater Classification (Water Framework Directive) (England and Wales) Directions New and updated standards are currently being consulted upon (Defra, 2014) and revised EA Directions are expected in Implementation of the WFD is primarily achieved through a system of river basin management planning. The water bodies of England and Wales have been allocated to river basin districts depending on catchment areas and a plan drawn up for each. The two fundamental requirements of the WFD are to attain good status and that deterioration in the status of waters is prevented. Any new development must ensure that these two fundamental requirements of the Directive are not compromised. The RBMPs contain a programme of measures tailored to each catchment designed to ensure its water bodies achieve and maintain the appropriate status in accordance with the timelines set out in the WFD. The key environmental objectives of the WFD may be summarised as: prevent deterioration of aquatic ecosystems, protect them and improve their ecological condition; NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 8 of 44

48 achieve at least Good Status for all water bodies by 2015 and where this is not possible by 2021 or 2027; meet the requirements of the WFD protected areas; promote the sustainable use of natural water resources; phase out or reduce the release of pollutants that present harm to the aquatic environment; prevent or reduce pollution to groundwaters; conserve habitat and species that are dependent on water; and contribute to mitigating the effects of both drought and flood. Classifying WFD Status (surface water bodies) The EA s Method statement for the classification of surface water bodies (EA 2011a) sets out the elements used for the classification of surface water bodies. An overview of the classification process is shown in Figure 3.1 below. Classifications indicate where the quality of the water body is good, where it may need improvement, and what may need to be improved. They provide indicative baseline information to set the context for schemes such as the Aldhurst Farm scheme. They can also be used, over the years, to plan improvements, show trends and to monitor success. There are two status classifications which are commonly reported for surface water bodies, ecological and chemical. For a water body to be in overall good status both ecological and chemical status must be at least good. Ecological status classification Ecological status classification consists of an assessment of those quality elements presented in Table 3.1. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 9 of 44

49 Table 3.1: WFD Quality Elements supporting WFD Ecological Classification Quality Element Description Biological Physico-chemical Hydromorphological Specific pollutants Numeric measures, such as Ecological Quality Indices, for aquatic biota that includes fish, invertebrates, macrophytes, phytoplankton (including diatoms). Measurements of water quality elements that support aquatic ecology that includes ph, temperature, dissolved oxygen, nutrient status and pollutants. Qualitative assessment of physical habitat conditions that includes flow regime and sediment dynamics and composition (hydrology and morphology). Further specific chemical parameters, such as zinc, cypermethrin or arsenic (Annex VIII substances). The decision tree presented as Figure 3.1 illustrates the criteria used to determine the different ecological status classes. Figure 3.1: Basis for WFD Ecological Classification (taken from EA, 2011a) The classification of ecological status for the water body and the confidence in this is determined by the worst scoring quality element. Hydromorphological elements are included as part of the status classification for water bodies of a high ecological status. For lower ecological status/potential, hydromorphological values are not specified, but nonetheless they indirectly contribute in supporting the biological quality elements for which the water body is classified. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 10 of 44

50 A summary of the biological, physico-chemical and hydromorphological elements for rivers i.e. the surface water body type most relevant to the proposed Aldhurst Farm scheme are presented in Table 3.2. Table 3.2: Quality Elements for River WFD Water bodies Quality Element Description (where necessary) Biological elements Fish Macro-invertebrates Aquatic macrophytes Phytobenthos All migratory and resident fish species including eels and lamprey. Wide range of pressures but primarily morphological change, abstraction of water and water quality. Aquatic insects, worms and molluscs living on the river bed or within macrophytes. Pressure from changes in water quality and changes in flow regime. Higher plants visible to naked eye growing within the river channel or in riparian areas. Pressure from nutrient enrichment and morphological alterations. Include small, bottom living algae (biofilms growing on rocks or plants) e.g. diatoms. Pressure from nutrient enrichment. Physico-chemical elements ph - Ammonia (total as N) - Phosphate - Dissolved oxygen - Specific pollutants Annex VIII parameters Hydromorphological elements Quantity and dynamics of water flow Connection to groundwater River continuity River depth and width variation Structure and substrate of river bed Structure of the riparian zone Hydrological attribute Hydrological attribute Morphological attribute Morphological attribute Morphological attribute Morphological attribute Chemical status classification Chemical status is determined by assessing compliance with environmental standards for chemicals that are listed in the Environmental Quality Standards Directive NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 11 of 44

51 (2008/105/EC) and under other relevant European legislation setting environmental quality standards. Chemical status is recorded as either good or fail. The chemical status classification, including certainty of failure, for the water body is determined by the worst scoring chemical. Groundwater status - chemical and quantitative The achievement of good status in groundwater involves meeting a series of conditions which are defined in the WFD (2000/60/EC) and Groundwater (Daughter) Directive (2006/118/EC). In order to assess whether these conditions are being met, a series of tests has been designed by the EA for each of the quality elements defining good (chemical and quantitative) groundwater status. There are five chemical and four quantitative tests. Each test is applied independently and the results combined to give an overall assessment of groundwater body chemical and quantitative status. The worst case classification from the relevant chemical status tests is reported as the overall chemical status for the groundwater body. The worst case classification of the quantitative tests reported as the overall quantitative status for the groundwater body. The worst result of these two is reported as the overall groundwater body status. Groundwaters are classified as either at good or poor status. A groundwater body will be classified as having poor quantitative status in the following circumstances; where low groundwater levels are responsible for an adverse impact on rivers and wetlands normally reliant on ground water; where abstraction of groundwater has led to saline intrusion; or where it is possible that the amount of groundwater abstracted will not be replaced each year by rainfall. Poor chemical status occurs if there is widespread diffuse pollution within the groundwater body; the quality of the groundwater is having an adverse impact on wetlands or surface waters; there is saline intrusion due to over abstraction; or the quality of water used for potable supply is deteriorating significantly. There are other objectives for groundwater quality in addition to meeting good status. These are the requirements to prevent or limit the input of pollutants to groundwater and to implement measures to reverse significant and sustained rising trends in pollutants in groundwater. Ecological Potential For water bodies that have been designated as heavily modified or artificial, the EA must classify according to their ecological potential rather than status. The UK has adopted the mitigation measures approach for classifying heavily modified and artificial water bodies. A number of different factors are considered when making an assessment of the ecological potential of heavily modified or artificial water bodies. These factors are an assessment of river flow, the presence or absence of mitigation measures, and the NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 12 of 44

52 status of other quality elements. These come together to provide an overall assessment of ecological potential as shown in Figure 3.2 below, taken from EA (2014b). Figure 3.2: Defining Ecological Potential (taken from EA, 2014b) Assessing Deterioration in WFD Status This WFD assessment adopts a precautionary approach with regards to the definition of deterioration of WFD status. A reduction in any one of the supporting quality elements defined in the current WFD water body description that leads to an overall reduction in ecological status or potential, would constitute a deterioration of WFD status. Deterioration is also defined within this assessment as an impact that compromises the potential for the water body to achieve its predicted future ecological status/potential within the specified timeframe. Mitigation measures or Actions required to achieve a Good ecological status or potential (for heavily modified water bodies) are listed within the RBMP. Therefore, the definition of deterioration may also be extended to include impacts that prevent or inhibit the necessary mitigation measures from being implemented. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 13 of 44

53 4 ASSESSMENT METHODOLOGY The adopted approach for the WFD assessment as set out in this section of the report, is based on: the methodology as detailed in the guidance note Carrying out a Water Framework Directive Assessment (WFD) Assessment on EIA Developments issued by the Northern Ireland Environment Agency (NIEA 2012), which in the absence of published guidance specifically in relation to England represents a complete, structured methodology regarding WFD assessments; and Internal (unpublished) EA guidance (which provides further information but which is deemed compatible to the NIEA methodology): o o o Environment Agency (2011b): Assessing impacts on water bodies in planning; Quick guide; Environment Agency (2010): Assessing new modifications for compliance with WFD: detailed supplementary guidance. Environment Agency (draft - unpublished): Interim Water Framework Directive Assessment and Statement of Compliance. 4.1 Stage 1 WFD water body review The current WFD water body descriptions for the surface and groundwater bodies related to the proposed Aldhurst Farm site were reviewed and are presented in Section 5. Information was sourced from the local River Basin Management Plans (RBMPs), including the draft Cycle 2 RBMP (out for consultation) (available online at 1 ), the EA s What s In Your Backyard website (online at 1 ), and the EA s new Catchment Data Explorer (online at 1 ). Review of the WFD water body information involves examining the described WFD supporting elements, the current WFD status, future status, identified environmental constraints and any existing or proposed mitigation measures. Where possible examination of the WFD water body descriptions is combined with a review of relevant historical or contemporary summary baseline information (in so far as it relates to supporting features of the water bodies). 1 Website visited 29 October NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 14 of 44

54 4.2 Stage 2 Assessment of the scheme A description of all elements and activities of the Aldhurst Farm scheme that may potentially affect the WFD status of the study water bodies has been developed. Potential effects (or impacts) that have already been identified in concurrent reports that relate to this scheme are referred to in this WFD assessment. The potential impacts are compared against the WFD classification elements for the water bodies and against the following WFD objectives: Objective 1: To prevent deterioration in the ecological status of a water body. Objective 2: To prevent the introduction of impediments to the attainment of Good WFD status for the water body. Objective 3: To ensure the attainment of the WFD objectives for the water body are not compromised. Objective 4: To ensure the achievement of the WFD objectives in other water bodies within the same catchment are not permanently excluded or compromised. 4.3 Stage 3 Mitigation discussions Where an element or activity from the Aldhurst Farm scheme is found in the absence of any mitigation measures (including design mitigation i.e. those mitigation principles that are incorporated into the project design) to be incompatible with achieving the four WFD objectives, mitigation measures (including integral design mitigation) to ensure compliance are discussed. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 15 of 44

55 5 BASELINE WATER ENVIRONMENT 5.1 Surface Water body Review During the first cycle of WFD reporting (EA, 2009) the Leiston Beck formed part of a larger surface water body in combination with the Minsmere Old River (collectively known by the water body ID GB ). The water body boundaries have been revised for WFD Cycle 2 with Leiston Beck and the Minsmere Old River being split into separate WFD water bodies. This split is appropriate given that these are two independent watercourses with two different sources and which effectively have no potential to influence one another (as confirmed via EA data request, October 2014). The Minsmere Old River, in particular, runs through the RSPB reserve at Minsmere and as such has different ecological and control needs to the Leiston Beck. The two watercourses both discharge to the sea via the Minsmere Sluice. Aldhurst Farm is located wholly within the catchment of the Leiston Beck water body (Cycle 2: GB ), upstream of the EA main-river i.e. upstream of the main WFD watercourse but within its catchment area. The surface water catchment boundary of the Leiston Beck (Cycle 2) water body is shown on Figure 5.1. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 16 of 44

56 Figure 5.1: Surface Water catchment boundary of the Leiston Beck (Cycle 2) WFD water body In the 2009 RBMP, within which the Leiston Beck and Minsmere Old River are combined, the overall Ecological Quality was reported as Moderate Potential. During the preparation of this report, details of the annual updates were requested from the Environment Agency and these are provided within Table 5.1. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 17 of 44

57 Table 5.1: Annual updates to Cycle 1 water body (Leiston Beck and Minsmere Old River) Baseline Biological Moderate Poor Poor Poor Poor Physico-chemical Moderate Good Moderate Moderate Moderate Chemical status DNRA DNRA DNRA DNRA DNRA Table notes: DNRA = Does not require assessment Given that the characteristics of the revised (Cycle 2) water body i.e. Leiston Beck, on its own may be very different to the Cycle 1 water body, this assessment, in terms of characterising the baseline environment is focussed on the 2013 data that are presented specifically with respect to the Cycle 2 water body. A summary of the Leiston Beck (2013 interim Cycle 2) WFD characterisation data (collated from the EA s published (online) consultation materials e.g. catchment data explorer: is presented as Table 5.2. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 18 of 44

58 Table 5.2 Details for the Leiston Beck Water Body Element Classification Water body ID GB Water body Name Leiston Beck Management Catchment Operational Catchment East Suffolk Suffolk Coastal River Basin District Anglian Typology Description Low, Small, Calcareous 1 Hydromorphological Status Heavily Modified Water Body overall status/potential Current Ecological Quality Moderate Potential (Target: Good) Moderate (Target:Good) Current Chemical Quality Good Biological Quality Elements Not assessed Hydromorphological Supporting Elements Not high Physico-chemical quality elements Moderate (Target:Good) Specific Pollutants High Priority Hazardous Substances Good Priority Substances Not assessed Supporting elements (Surface Water) Not assessed ph High Ammonia (Phys-Chem) High Fish Not assessed Invertebrates Not assessed BOD High Dissolved Oxygen Good Phosphate Bad 2 (Target:Good) Temperature High Cycle 2 Mitigation Measures Assessment Moderate or less 3. Cycle 1 Mitigation Measures Assessment (EA, 2009) Physical modification risk assessment (of not achieving good potential due to physical modification pressure) Sediment risk assessment (of not achieving good potential due to sediment pressure) Overall Objective Ecological Objective Chemical Objective Hydromorphological Objective Physico-chemical Objective Moderate. Those mitigation measures not in place: Appropriate channel maintenance strategies and techniques - minimise disturbance to channel bed and margins; Improve floodplain connectivity; Set-back embankments; Flood bunds (earth banks, in place of floodwalls). At risk (EA 2009 report a morphology risk due to land drainage) Not at risk Good Good Good Not High Good NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 19 of 44

59 Table notes: 1 Taken from cycle 1 data (EA 2009) assumed no change 2 Note that physico-chemical supporting quality elements can only influence status down to moderate. 3 Taken from EA s proposed Cycle 2 Mitigation Measures Assessment at (accessed 11/12/2014) The Environment Agency has recently published draft Cycle 2 Mitigation Measures Assessment (MMA) results ( - accessed 11/12/2014). The draft 2014 MMA (cycle 2) result for Leiston Beck is Moderate or less, which means that at least one Mitigation Measure that is required in this water body hasn t yet been implemented so the MMA has not reached Good. It is not possible for this water body to achieve GEP even if all the other relevant elements in the water body are Good. The best it can achieve is Moderate Ecological Potential. The individual measures that support the draft 2014 MMA have not yet been published, however the EA have confirmed (consultations with Neil Dinwiddie, EA Project Coordinator) that the existing Cycle 1 mitigation measures (as listed in Table 5.2) may be used within this assessment as it is very unlikely that these will change. These mitigation measures are taken into account within Section 6.3. The reason for the overall 2013 status of Moderate Potential is on the grounds of the phosphate analysis which found concentrations consistent with Bad status (physicochemical supporting quality elements can only influence status down to moderate) and the Mitigation Measures Assessment. From the downstream site boundary at Lovers Lane, it is over 4km to the point at which the Leiston Beck discharges to the sea via Minsmere Sluice. Given this large distance, the coastal nature of the downstream water body and assuming that protection to the Leiston Beck WFD water body is afforded, it is considered unnecessary to consider the downstream coastal WFD water body (Suffolk coastal water body; GB ). 5.2 Groundwater body Review The EA s Catchment Data Explorer and the draft (for consultation) Anglian RBMP (EA 2014b) do not contain information on the Cycle 2 groundwater bodies (it is presumed that the data explorer will be updated with this information in due course). In this period of transition between the WFD reporting cycles it was deemed appropriate to consider Cycle 1 data (as presented in the 2009 RBMP (EA 2009)) within this report. Aldhurst Farm is located wholly within the boundary of the Waveney and East Suffolk Chalk & Crag (GB40501G400600) groundwater body. The 2009 RBMP WFD classification details of this groundwater body are summarised in Table 5.3 and the risk classifications taken from the draft 2015 consultation are presented as Table 5.4. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 20 of 44

60 Table 5.3 Details for the Waveney and East Suffolk Chalk & Crag Groundwater Body, taken from 2009 RBMP Element Classification 1 Water body ID Water body Name River Basin District Quantitative Status Chemical Status Upward Chemical Trend GB40501G Waveney and East Suffolk Chalk & Crag Anglian Good (Low certainty) Poor (Low certainty) No 2015 Quantitative status objective Good 2027 Chemical Quality status objective Good (2027) Protected Area Pressures Yes Drinking Water Protected Area (DrWPA), Nitrates Directive Nutrients (nitrate and phosphate); Hazardous Substances and other pollutants (Pesticides and DrWPA); Abstraction and other artificial flow pressures (DrWPA and Saline intrusion). Quantitative Quality RBMP (2009) status (and confidence) Predicted 2015 status Impact on wetlands Good (Low) Good Impact on surface waters Good (Low) Good Saline intrusion Good (Low) Good Water balance Good (Low) Good Chemical Elements RBMP (2009) status (and confidence) Predicted 2015 status Drinking Water Protected Area Good (Low) Good General Chemical Test Poor (Low) Poor Disproportionately expensive (GC4a) Impact on Wetlands Good (Low) Good Impact On Surface Waters Good (High) Good Saline Intrusion Good (High) Good Good Chemical Status is Predicted for Further Details and table notes GC4a - The costs of the measures are disproportionately expensive to achieve by Elements predicted not to achieve good by 2015: Drinking Water Protected Area, General Chemical Assessment and Impact on wetlands. Reason for failure: confirmed - diffuse source agricultural failures are caused by nitrate and/or ammonia. Extended deadline proposed as objective due to being disproportionately expensive. As the deadline is extended to 2027, less costly measures can be used to achieve good status, including Nitrate Vulnerable Zone action programmes, England Catchment Sensitive Farming Delivery Initiative, water company lead catchment management schemes, Safeguard Zones, Water Protection Zones, targeted setaside and targeted measures with agri-environment schemes. 1Taken from cycle 1 RBMP (EA 2009). NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 21 of 44

61 Table 5.4 Details for the Waveney and East Suffolk Chalk & Crag Groundwater Body, taken from draft 2015 RBMP (EA 2014b) Element Classification Water body ID GB40501G Water body Name River Basin District Waveney and East Suffolk Chalk & Crag1 Anglian Groundwater Quantitative Impact on water balance Impact on surface water Impact on Terrestrial Ecosystems Impact on Saline Intrusions All quantitative pressures Probably at risk At risk Probably at risk At risk At risk Groundwater Chemical Test Impact on groundwater quality Impact on surface water chemistry and ecology Risk of saline intrusion Impact on DrWPA Impact on wetlands (groundwater dependent terrestrial ecosystems) Overall risk of not achieving groundwater chemical status now to 2027, including risk of deterioration Chemical trend assessment to 2027 At risk At risk At risk At risk Probably at risk At risk At risk The Waveney and East Suffolk Chalk & Crag groundwater body covers a large area and not all characteristics as described in Table 5.3 will be directly applicable to the groundwater underlying the Aldhurst Farm site. For example, the proposed site does not lie within any groundwater Source Protection Zones or drinking water protected area safeguard zones. The Aldhurst Farm site does lie within a (large) surface water and groundwater Nitrate Vulnerable Zone (NVZ) (although it does not lie within a Eutrophic NVZ area). 5.3 Further baseline characterisations Surface water sampling in the Leiston Beck next to Lovers Lane (SW1) (as reported, for example, in RHDHV, 2013) indicates that water quality is impacted by the Leiston WWTW with elevated concentrations of nitrogen (nitrate), phosphorus and potassium. ph values for surface water varied from 7.5 to 8.8 (mean 8.1). Dissolved oxygen concentrations in surface waters were also low and electrical conductivity was low and typically less than 2500 us/cm. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 22 of 44

62 Groundwater samples (BH1) (eastern edge of valley) are characterised by chloride concentrations typically about 100 mg/l and sulphate in the range 100 to 200 mg/l (RHDHV, 2013). Samples for borehole BH4 (top of the valley) were characterised by variable high chloride and sodium concentrations which indicate drainage of road runoff to groundwater. The ph for groundwater typically ranges from 6.5 to 8.6 (mean 7.3). Overall the groundwater chemistry was deemed to be suitable for reed beds. The monitoring data show no evidence of contamination that could be associated with nearby closed landfill sites or other potential sources of contamination that have been identified. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 23 of 44

63 6 RESULTS WFD ASSESSMENT 6.1 Introduction The aim of this section is to assess the potential for the scheme s components to affect the two identified WFD water bodies. Each water body is examined in turn, and the potential impacts on individual WFD elements are assessed. The components of the scheme listed in Section 6.2 are assessed in the context of the available baseline information for the two water bodies (Section 5) within the subsequent sections. On account of the proposed scheme being located upstream of the WFD waterbody (mainriver) and largely isolated from the local supporting watercourses (those watercourses within the waterbody catchment area, that support the downstream WFD waterbody), the assessment on each WFD element in Section 6.3 and Section 6.4 is undertaken cumulatively i.e. it is not considered necessary in this instance to consider individual scheme components against individual WFD elements. Where required, further detail on the scheme components and potential interactions with WFD elements are provided in the assessment tables. The scheme components are assessed for all phases of the development (construction and post-construction), with the focus being to identify the potential for any adverse effects. The assessment is based on scheme design measures and other environmental measures which are presented in a number of other documents supporting the planning application including the Design Statement (AMEC 2014b), the Construction Method Strategy (CMS) (AMEC 2014c) and the Flood Risk Assessment (AMEC 2014d). 6.2 Consideration of the scheme Further to the general introduction of the proposed Aldhurst Farm scheme provided within Section 2, Table 6.1 introduces those specific components of the scheme which are directly applicable to a consideration of potential effects on the WFD environment (i.e. on the surface and groundwater environment in the locality). Table 6.1 Details of scheme components relevant to this assessment Scheme components In channel structures Water levels Discussion The proposed scheme design does not involve any permanent control structures being constructed within the existing watercourses, although two temporary culvert crossings are proposed during the construction phase. The four basins have been designed to ensure areas of reedbed are likely to remain permanently wet, even under drought and fully licensed abstraction conditions. The outflows from the four basins will be to the Aldhurst Valley Stream and the Leiston Beck, via pre-cast concrete structures with stop boards; to allow control of water levels. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 24 of 44

64 Table 6.1 (continued) Details of scheme components relevant to this assessment Scheme components Discussion Control structures Off-set distances Eel passage Water supply Change to existing water features including stream re-alignment Width and slope Internal perimeter ditches Sourcing of reeds Basins A and C will also be connected via a channel with control structure to provide flexibility in terms of management of basin water levels and flows. The channels will be constructed using pre-cast concrete pipes (AMEC, 2014b). Note these structures are between basins and not within existing watercourses. The control structures will be designed to allow eel passage. Water levels will be managed for the maximum benefit of wildlife. Typical water levels are presented in the Design Statement (AMEC, 2014b). Control structures will be constructed between each basin and the existing watercourses. These will be designed to allow eel passage. With the exception of drought conditions there is expected to be an outflow of 1 to 2l/s from each basin (AMEC, 2014b) which will support flow in the Leiston Beck. A minimum of a 5m off-set (excluding the bank sides) has been allowed between the existing watercourses and the groundwater basins. Water control structures will allow for eel passage, facilitating eel access to the basins. The base of the wet reedbed areas will be excavated to 0.1m below the minimum predicted groundwater level. The wet reedbed area open water pools will be excavated to a typical depth of about 2.5m below original ground level to provide a water depth of 1.5m under average summer water levels. In the winter, the typical water depth will be over 1.7m. The base of the open water pools will be varied to provide some variation in water depth. The proposed Basin A area will be constructed to incorporate part of the former irrigation pond area (currently comprises reed and wooded area (poplars)). In doing so some minor realignment of the Aldhurst Valley stream will also be undertaken, in order to remove two right angle bends associated with the former irrigation pond and these bends will be altered to reduce erosion risk and to provide a more natural profile. Where the Aldhurst Valley Stream flows through the former irrigation pond, the banks will be raised to original ground levels. A minor ditch currently runs from Brick Kiln Farm to the Aldhurst Valley Stream. As part of the ground lowering works to the west of Basin A, this ditch will be diverted into the perimeter ditch to Basin A to provide a small additional inflow. The line of the open water channels connecting the pools will be sinuous. The width and side slopes of the pools will also be varied to create a sinuous profile. Localised variations in bed slope will provide variability of edge habitat and cater for areas optimised for considerations that include water vole habitat and areas of health and safety concern. Three of the basins (A, B and C) will have an internal perimeter ditch. No continuous perimeter ditch will be constructed for Basin D. The total length of these ditches is estimated as 2000m. Reed for planting within the basins will be sourced from commerciallyavailable nursery stocks. The source of the reed for the perimeter ditches will be ditch slubbings from a suitable local site. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 25 of 44

65 Table 6.1 (continued) Details of scheme components relevant to this assessment Scheme components Substrate Flood risk considerations Stream flows and stream support Access Soil Discussion The substrate for the reeds will be either peat or clay and will have a thickness of about 0.3m. For the majority of the excavation area, there will be sufficient thickness of peat left in place to provide a suitable substrate. However in some parts of the basins (e.g. western part of Basin A and the south western part of Basin C) excavation will be to below the base of this deposit requiring some over digging of sand (typically) and replacement by peat to create a substrate layer 0.3 m thick. The Aldhurst Valley Stream, Leiston Beck and WWTW ditch will continue to be maintained e.g. removal of sediment to facilitate water passage (access has been provided for the Internal Drainage Board and Anglian Water). This reflects on-going maintenance of these watercourses. The construction of the four basins and proposed water level management would provide some additional flood storage e.g. associated with flood water backing up above height of stock boards (associated with discharge structures) and therefore a potential benefit to the baseline environment which is subject to flood risk. Change to the groundwater and surface water regime is expected to be small (AMEC, 2014b). The basin water levels are below existing groundwater levels and would therefore result in a localised lowering of groundwater levels. Under most conditions the basins will outflow to the Aldhurst Valley Stream and Leiston Beck. This is unlikely to result in a significant change in flows in the Leiston Beck downstream of the site as this will be balanced by a decrease in groundwater discharge to the stream. The creation of wet reedbed and open water habitat in the basins has the potential to result in evapo-transpirative loss and a reduction in flow in the Leiston Beck. Water balance calculations indicate a potential loss of up to 3l/s, but are more typically between 1 and 2l/s in the summer. The EA has identified that flow in the stream should not fall below 11/s. Under this scenario, flow in the Beck would be supported by a groundwater abstraction, but this is only likely to be required under drought conditions. A new borehole will be drilled in order to provide augmentation flows in the Leiston Beck when flows at Lovers Lane fall below 11l/s. The existing licensed spray irrigation licence will be varied for this purpose. The location of the new borehole will ensure no derogation of existing licences or groundwater supplies (to the proposed basins or the adjacent SSSI). Existing spray irrigation licence volume would allow stream support for a period of ~100 days per annum. Access points will be constructed on the basin edges to allow reedbed maintenance and cutting. Each basin will have two access points which will comprise a ramp down onto a berm with a culverted bridge across the perimeter ditch where present. Culverts will also be placed within open water channels to allow access across the basin for maintenance purposes. Excavated soils (from basin creation) will be used within the Aldhurst Farm site. Peat will be used as reed substrate and as a soil conditioner across the wider site to make the soils more acidic, suitable for the establishment of heathland mosaic. Excavated topsoil will be used in areas for creation of neutral grassland and scrub. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 26 of 44

66 Table 6.1 (continued) Details of scheme components relevant to this assessment Scheme components Discussion Wider environmental considerations Construction dewatering Discharge of dewatered water Silt-laden runoff Construction of basins Site entrance Temporary Construction Compound and Laydown Area The wider Aldhurst Farm site will be used to create a mosaic of grassland, heathland and scrub (including Suffolk BAP habitats). Any new hedgerows (or works to gap up existing hedges) will use a diverse species mix. Details of habitat creation proposals for the Site are given in the Ecology and Landscape Management Plan. Due to the basins being constructed below the water table groundwater dewatering will be required prior to the construction of each basin. The CMS (AMEC 2014c) and the Design Statement (AMEC 2014b) provide further detail on the general methodology, which in summary involves: dewatering will be undertaken using either a well point system and/or pumping from a sump(s) within the basin areas; monitoring of the pumped water quality and discharge to the Aldhurst Valley Stream or Leiston Beck. If required the water will be treated prior to discharge. A temporary settlement pond will be created in Basin and if necessary pumping between basins to provide further settlement. A trial will be undertaken to inform on the dewatering and treatment design as part of the preparatory works. Management/treatment of water from dewatering and construction areas will be required prior to discharge to the Aldhurst Valley Stream or Leiston Beck in accordance with an Environmental Permit. During construction, areas of ground will be exposed with the potential to create silt entrained run off. The preferred method of managing surface water at Aldhurst Farm during construction is through the use of gravel interception ditches, following the application of appropriate management measures to prevent pollution. Measures will include: appropriate scheduling of works having regard for weather conditions; installation of cut-off drains with check dams; silt traps, silt fences and straw bales as appropriate; prompt re-vegetation of wetland basins; adherence to EA PPG and CIRIA C692 (CIRIA 2010) guidance. The CMS (AMEC 2014c) provides a construction sequence with respect to the construction of the basins, which is designed to allow settlement of waters prior to any discharge from the site and increasing levels of surface water control. The site entrance (off the B1122) will be the main access point into the site. The temporary construction compound will be located within the Aldhurst Farm site, adjacent to the site access. Electrical power may be provided by generator with a bulk fuel oil tank (providing typically not less than seven days operation capacity without refuelling). Welfare facilities may discharge to a sealed tank, which will be routinely emptied by tanker, for disposal offsite. Typical construction activities associated with the establishment of a temporary site compound are set out in the CMS and include: top soil stripping, placement of suitable granular material to provide a base; and provision of an impermeable bunded area for storage of fuel oils. Buffer zones Demarcation fencing will be installed along watercourses (where appropriate) to provide a 5m buffer zone to protect the habitat of water voles and segregate watercourses from construction activities and potential runoff. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 27 of 44

67 Table 6.1(continued) Details of scheme components relevant to this assessment Scheme components Discussion Removal of existing borehole and pump house Construction of new abstraction borehole Temporary culverts Storage of oils, fuels and chemicals Water quality monitoring Pollution Response Plan Incident The removal of the existing abstraction borehole and pump house is required to facilitate the construction of the ground water basins. The borehole will be decommissioned in accordance with the Environment Agencies guidance for Decommissioning Redundant Boreholes and Wells. A new below ground abstraction borehole and above ground pump house will be constructed. The CMS (AMEC 2014c) provides a general methodology for the new boreholes. These boreholes will be licensed through a variation of the licence for the spray irrigation boreholes. Two temporary culverts will be constructed to allow for construction plant to cross the Aldhurst Valley Stream and the WWTW. These will be covered by a consent from the Internal Drainage Board and removed on completion of the works. Construction will be in accordance with the Construction Management Strategy and Ecology and Landscape Management Plan. Any bulk storage of diesel fuel for example will be 110% bunded and located at least 20m from any water courses. All other chemicals (small quantities of chemical additives for example) will be stored in a secure fixed COSHH store). Drip trays will be employed during refuelling/maintenance activities and refuelling will be subject to a detailed method statement and risk assessment prepared by the contractor. Proprietary oil spill kit will be carried by all construction vehicles with additional kits positioned at appropriate locations around the site. Water quality monitoring will be undertaken during the construction phase to assess and manage the performance of site drainage, making adjustments as necessary to ensure that the site drainage does not impact on local groundwater or surface watercourses. Monitoring will be undertaken at three locations: Aldhurst Valley Stream (upstream of discharge point for dewatering), WWTW (upstream of discharge point for dewatering), and the Leiston Beck (downstream of discharge point for dewatering). Details are given in the CMS. A detailed Pollution Incident Response Plan will be prepared by the contractor to identify the anticipated method for dealing with spillages. Table notes: Scheme details taken largely from the CMS (AMEC 2014c). NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 28 of 44

68 6.3 Leiston Beck WFD Unit (ID: GB ) Biological Elements Table 6.2 Assessment of impact of proposed scheme on biological elements WFD Element Discussion Fish WFD water body. There has been no WFD assessment of fish in this waterbody (Cycle 2); overall ecological quality currently at moderate status. No direct impact from the scheme is anticipated (scheme located u/s of EA main-river). Indirect impacts would also be avoided water quality monitoring, and measures to prevent pollution and silt-laden runoff will minimise any effects on water quality d/s of the site. Potential for some flow augmentation during periods of low flow/drought. See potential beneficial effects discussed below. Supporting watercourses. There will be very limited fish populations in the Aldhurst Valley Stream and Leiston Beck u/s of Lovers Lane (on account of small flows, width and habitat type) - there has been no WFD assessment of fish in the d/s waterbody. There are no planned in-channel works, other than some minor realignment of the Aldhurst Valley Stream and installation of temporary access culverts; there will be negligible habitat loss as a result of the scheme. The four new basins will provide significant additional fish nursery habitat, which is currently not available in this subcatchment. It is assumed that some recruitment potential to downstream areas may be offered through the d/s connectivity via the basin outflow structures. There are no plans to stock the basins, however natural recruitment of native fish species would be expected over time. The basins will offer particularly good eel habitat and the outflow structures will be designed to facilitate u/s and d/s eel passage. Thus the scheme offers improved and expanded habitat availability for fish. Overall, the scheme components would not adversely affect, and has potential to offer significant improvement to, this WFD Element. Disturbance during the construction phase with regards potential for poor water quality runoff would be mitigated through appropriate construction phase controls e.g. settlement ponds and water quality monitoring. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 29 of 44

69 Table 6.2 (continued) Assessment of impact of proposed scheme on biological elements WFD Element Discussion Macro- Invertebrates WFD water body. There has been no WFD assessment of macro-invertebrates in this waterbody (Cycle 2); overall ecological quality currently at moderate status. No direct impact from the scheme is anticipated (scheme located u/s of EA main-river). Indirect impacts would also be avoided water quality monitoring, measures to prevent pollution and silt-laden runoff will minimise any effects on water quality d/s of the site. Potential for some flow augmentation during periods of low flow/drought. See potential beneficial effects discussed below. Supporting watercourses. There are not anticipated to be any invertebrate populations of particularly high value or species of conservation interest, on account of shallow, generally slow flowing, lowland agricultural ditches/watercourses - there has been no WFD assessment of macro-invertebrates in the d/s water body. There are no planned in-channel works, other than some minor realignment of the Aldhurst Valley Stream and installation of temporary access culverts; there will be negligible habitat loss as a result of the scheme. The four new basins, associated reed beds and perimeter ditches will provide additional macro-invertebrate habitat, which is currently not available in this subcatchment. It is assumed that some limited potential to recruit/expand population downstream would be offered via the basin outflow structures. Utilisation of ditch slubbings from Retsoms (removed by Suffolk Wildlife Trust) will encourage establishment of macro-invertebrate populations within the ditches. Thus the scheme offers improved and expanded habitat availability for macro-invertebrates. Potential water quality impacts on existing watercourses will be mitigated through appropriate construction drainage management in particular; monitoring should focus on suspended sediment concentrations (sediment having the potential to smother) and acidity (which could potentially be affected if peat is not managed appropriately) although sensitivity of these watercourses would be deemed to be low (especially on account of expected baseline high suspended sediment concentrations e.g. riparian arable landuse). Overall, the scheme components would not adversely affect, and has potential to offer significant improvement to this WFD Element (associated with habitat expansion following scheme completion). Macrophytes WFD water body. There has been no WFD assessment of macrophytes in this waterbody (Cycle 2); overall ecological quality currently at moderate status. No direct impact from the scheme is anticipated (scheme located u/s of EA main-river). Indirect impacts are also not anticipated. Potential for some flow augmentation during periods of low flow/drought. See potential beneficial effects discussed below. Supporting watercourses. Some limited macrophytes in the Aldhurst Valley Stream would be lost when a small section of this watercourse is realigned, however the spatial scale of this is small and macrophytes not expected to be notable species. Removal of the irrigation pond may overall return the watercourse to a more natural state, given that the pond area may be acting as a barrier to the establishment of in-stream communities. The four new basins, associated reed beds and perimeter ditches will provide specifically designed aquatic macrophyte habitat, which is currently not available in this subcatchment. Utilisation of ditch slubbings from Retsoms (removed by Suffolk Wildlife Trust) will encourage establishment of macrophytes within the ditches. The site will be managed specifically for the benefit of the aquatic habitats. Thus the scheme offers enhanced potential for macrophytes, especially given that the current agricultural land use will be transferred to an aquatic macrophyte dominated landuse within the wetland habitat creation area. Overall, the scheme components would not adversely affect this WFD Element and will offer significant potential benefits. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 30 of 44

70 Table 6.2 (continued) Assessment of impact of proposed scheme on biological elements WFD Element Discussion Phytobenthos WFD water body. There has been no WFD assessment of phytobenthos in this waterbody (Cycle 2); overall ecological quality currently at Moderate status. No direct impact from the scheme is anticipated (scheme located u/s of EA main-river). Indirect impacts are also not anticipated. Potential for some flow augmentation during periods of low flow/drought. Greatest influence on watercourse phytobenthos likely to arise from organic inputs from the WWTW, which will not be affected by the proposed scheme. Supporting watercourses. Little potential to affect phytobenthos of these small watercourses. Once habitat scheme in place, the diatom response which is largely nutrientled will have less potential to be affected by diffuse agricultural runoff. Very little potential for the scheme to affect indirect d/s changes to phytobenthos. Overall, the scheme components would not adversely affect this WFD Element and may provide benefit. ph WFD water body. Current ph status of d/s Leiston Beck WFD water body is high. No direct impact from the scheme is anticipated. Indirect impacts will be mitigated via appropriate water discharge management, monitoring and controls, particularly with regards to management of excavated peat and sediment laden runoff. A water monitoring strategy will include provision for ph and sediment monitoring. Supporting watercourses. During the construction stage, water quality monitoring and appropriate management and placement of peat spoil in particular will ensure that acidic runoff does not occur (further details are provided in the Materials Management Plan, AMEC (2014d)). The off-line construction and groundwater dewatering will limit the interactions with surface watercourses during the construction period. Off-line construction and working methods would avoid concrete residue/washwater entering adjacent watercourses; water level control structures will be pre-cast. When complete, monitoring of the ph of discharged flows will not be necessary and will be equivalent to downstream ph conditions (independent of any influence from the WWTW). Overall, the scheme components would not adversely affect this WFD Element. Adherence to the construction method statement and surface water drainage plan would manage any potential impact. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 31 of 44

71 Table 6.2 (continued) Assessment of impact of proposed scheme on biological elements WFD Element Discussion Ammonia WFD water body. Current ammonia status of d/s Leiston Beck WFD water body is High. No direct impact from the scheme is anticipated. Potential indirect impacts, which would be expected to be minor, would be mitigated via appropriate water discharge management, monitoring and controls, particularly with regards to management of excavated peat and sediment laden runoff. The vast majority of ammonia contributions to the d/s water body will derive from the WWTW (which is not under the influence of this scheme). Supporting watercourses. During the construction stage, water quality monitoring and appropriate management and placement of peat spoil in particular will ensure that runoff characterised by increased ammonia (which may potentially be influenced by for example, acidity and topsoils (which could be influenced by fertilisers, decaying organic matter or natural fixation from the atmosphere)). The off-line construction and groundwater dewatering will limit the interactions with surface water courses during the construction period. When complete, reedbed microbial action will likely reduce potential ammonia concentrations and offer a potential benefit relative to the baseline environment (runoff from arable agricultural fields where fertilisation currently occurs). Overall, the scheme components would not adversely affect this WFD Element. Adherence to the construction method strategy and surface water drainage plan would manage any potential impact. Phosphate WFD water body. Current phosphate status of d/s Leiston Beck WFD water body is Bad. No direct impact from the scheme is anticipated. Indirect impacts which would be expected to be minor/negligible (in relation to adsorbed phosphate associated with sediments), would be mitigated via appropriate water discharge management, monitoring and controls, particularly with regards to management of excavated soils and sediment laden runoff. Where possible excavated and reused peat will be kept moist/wet, which will help to minimise oxidation and mineralisation (and subsequent release of nutrients) and prevent any flushing of phosphorus which could be associated with re-wetting of dried peat and soils. A water monitoring strategy will include provision for P monitoring during the construction phase. The majority of phosphate loading contribution to the d/s water body (causing current bad status) will derive from the WWTW (which is not under the influence of this scheme). Given that there may be some augmentation of low flows d/s of the scheme offered by discharges from the basins (relative to baseline d/s flows) the scheme may offer some dilution of dry weather flow concentrations from the WWTW. Downstream improvements to phosphate concentrations in the water body are expected following installation of phosphorus removal infrastructure (chemical dosing) at Leiston WWTW. Supporting watercourses. During the construction stage, water quality monitoring, lowering of the water table (to enable dry working) and appropriate management and placement of soils in particular will ensure that runoff which may otherwise be characterised by increased phosphate concentrations (which may potentially be influenced by nutrients adsorbed to soils) is minimised. The off-line construction and groundwater dewatering will limit the interactions with surface watercourses during the construction period. Any temporary, construction related inputs of phosphate anticipated to be negligible in comparison to loading contributions from the WWTW. When complete, nutrient uptake by the reedbed will, assuming biomass is removed from the system via reed harvesting, reduce potential phosphate loadings and offer a potential benefit relative to the baseline environment (runoff from agricultural and often bare unplanted fields). Low flow augmentation may also provide potential dilution of downstream phosphate concentrations deriving from WWTW discharges. The scheme components would not adversely affect this WFD Element. Adherence to the CMS (AMEC 2014c) and surface water drainage plan would manage any potential impact during the construction phase. Some potential benefits from the completed habitat scheme. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 32 of 44

72 Table 6.2 (continued) Assessment of impact of proposed scheme on biological elements WFD Element Discussion BOD WFD water body. Current BOD status of d/s Leiston Beck WFD water body is High. No direct impact from the scheme is anticipated. Vast majority of BOD inputs to WFD water body will derive from the WWTW (which is not under the influence of this scheme). Indirect impacts which would be expected to be minor/negligible (in relation to runoff potentially containing peat which could impose an oxygen demand via bacteriological breakdown) during the construction stage would be mitigated via appropriate water discharge management, monitoring and controls, particularly with regards to management of excavated peat and sediment laden runoff. Any temporary, construction related scheme discharges with elevated BOD concentrations would be negligible in comparison to the concentrations associated with WWTW discharges. Supporting watercourses. During the construction stage, careful management and placement of peat in particular will ensure that runoff is not characterised by increased BOD concentrations. The off-line construction and groundwater dewatering will limit the interactions with surface watercourses during the construction period. Once the scheme is completed, discharges from the site would not be expected to be elevated in BOD, with the potential exception at the time of the seasonal vegetation dieback. However this would tend to reflect the conditions expected across the entire Leiston Beck catchment. Overall, the scheme components would not adversely affect this WFD Element. Adherence to the Construction Method Strategy would manage any potential (negligible) impact during the construction phase. Dissolved Oxygen WFD water body. Current DO status of d/s Leiston Beck WFD water body is Good. Catchment water quality monitoring in support of Sizewell C baseline environmental characterisation found DO concentrations to be variable but generally low. No direct impact from the scheme is anticipated. The majority of oxygen demand will derive from the WWTW (which is not under the influence of this scheme) and this is likely to be far in excess of any effects from the proposed scheme. Indirect impacts which would be expected to be minor/negligible (in relation to runoff potentially containing peat as per BOD above), would be mitigated via appropriate water discharge management and controls, particularly with regards to management of excavated peat and sediment laden runoff. Supporting watercourses. During the construction stage, water quality monitoring and appropriate management and placement of peat in particular will ensure (indirectly) that runoff is not characterised by low DO concentrations. The off-line construction and groundwater dewatering will limit the interactions with surface watercourses during the construction period. When the scheme is complete, discharges from the site expected to have DO concentrations representative of wider catchment, which will likely vary to a large extent due to seasonal vegetation die back and flow conditions, but generally good. Overall, the scheme components would not adversely affect this WFD Element. Specific Pollutants WFD water body. Current WFD status for Leiston Beck is High. No planned chemical discharges from scheme and disturbed land in agricultural use (baseline soil characterisations have not identified the presence of any pesticides). No/negligible potential for scheme to affect concentrations of specific pollutants (ammonia already discussed above). Supporting watercourses. Current WFD status for Leiston Beck is High. No planned chemical discharges from scheme and disturbed land in agricultural use (baseline soil characterisations have not identified the presence of any pesticides). No/negligible potential for scheme to affect concentrations of specific pollutants (ammonia already discussed above). Overall, the scheme components would not adversely affect this WFD Element. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 33 of 44

73 6.3.2 Hydromorphological Elements Table 6.3 Assessment of impact of proposed scheme on hydromorphological elements WFD Element Discussion Quantity and Dynamics of Flow WFD water body and supporting watercourse. As confirmed by the FRA (AMEC 2014d) there will be no change to the conveyance of the existing channels. Potential for flows in watercourses and d/s water body to be moderated at times of flood given some additional flood plain storage for extreme events resulting from presence of groundwater basins, offering some minor high flow benefit. Discharge of groundwater into the groundwater basins and the subsequent discharge of this flow via the control structures into the on-site watercourses is unlikely to result in an increase in surface water flow or an exacerbation of flooding. The development design will also provide additional benefit in the form of flow augmentation during periods of low flow. The discharge control structures will have a positive effect upon the new basins; they are designed to optimise the water level in the basins and control outflow rates (and thus positively influence all other basin related WFD elements). There will be a small reduction in the baseflow contribution to (the upper reaches of) the supporting watercourses on site, on account of the lowered water table but any change in flow will be limited - may affect in the region of one hundred metres i.e. within the upper catchment of the Aldhurst Valley Stream, above the location of the first of the basin discharges. The baseline flow in this area is very small and less dominated by baseflow than further d/s; therefore the change is considered to be negligible. Construction phase dewatering will be discharged to the local watercourses and therefore there will be no impact of lowered groundwater levels on d/s watercourse flow quantity. Control of discharge rates (of dewatered groundwater and basin water) will mitigate against any increase in d/s flood risk that may be posed by discharges at times of flood for example. The new borehole abstraction will ensure that flows in the Leiston Beck d/s of Lovers Lane of 11l/s are maintained even under drought conditions. For further detail regarding flow considerations please refer to Appendix B of the design statement (AMEC 2014b). Once the habitat scheme is completed the addition of open water to the existing watercourses in the landscape will improve the hydrological variety within the water body overall. Overall, the scheme components would not adversely affect this WFD Element. Connection to Groundwater WFD water body. No direct impact from the scheme is anticipated as the project boundary is located upstream of the Leiston Beck WFD water body and any groundwater abstractions will be returned to the surface water environment u/s of the main-river reach. Supporting watercourses. Groundwater connectivity with the on-site supporting watercourses is assumed and will be actively pursued in order to provide water supply to the basins. Local groundwater levels will be lowered both during the construction phase (temporarily using a well point system) and following scheme completion on account of the finished basin water level. Via the discharge control structures and the new borehole abstraction, the streams will be supported (all phases), so that flows at the final discharge point from the site are maintained at 11l/s. There will be no net abstraction from the groundwater catchment (assuming good connectivity is maintained d/s within the Sizewell Belts for example) and the local lowering of the groundwater level will be to the benefit of the habitat enhancement. For further detail regarding flow considerations please refer to Appendix B of the design statement (AMEC 2014b). Overall, the scheme components would not adversely affect this WFD Element. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 34 of 44

74 Table 6.3 (continued) elements Assessment of impact of proposed scheme on hydromorphological WFD Element Discussion River Connectivity WFD water body. No impact from the scheme is anticipated, since the main WFD water body reach is not curtailed or obstructed by the scheme. Supporting watercourses. No impacts on the connectivity of the supporting watercourses given no in-channel structures (other than temporary access culverts). Connectivity overall is improved given that additional water related habitat (basins) is made available to eels, with the basin discharge structures specifically designed to allow eel passage. There is potential for minor improvement with regards flood storage - thus a small improvement in terms of floodplain connectivity (this is in line with the assumed local WFD water body aspiration). Overall, the scheme components would not adversely affect this WFD Element. Following completion of the habitat scheme there would be an improvement in this component, particularly with regard to additional habitat and connectivity with regards eels. River Depth and Width Variation WFD water body. No impact from the scheme since the main WFD water body reach is not involved in the scheme and no works would take place here. Supporting watercourses. The planned works are limited to some minor realignment of the Aldhurst Valley Stream to remove two sharp bends. There may theoretically be some depth reduction in the short lengths of on-site watercourse on account of the lowering of the water table to supply the basins (following scheme completion) and during the dewatering during the construction phase, although this will take place upstream of the main-river and the surface water flows would be supported by the basins during very low flows, which is likely to be the only time when a depth reduction (due to less baseflow) would be evident. Any changes to watercourse banks would be minor. Overall, the scheme components would not adversely affect this WFD Element. Structure and Substrate of River Bed WFD water body. No impact from the scheme is anticipated, since the main WFD water body reach is not involved in the scheme and no works would take place here. Supporting watercourses. No in-channel works other than installation of access culverts that will be temporary. Construction phase pollution prevention measures and measures to prevent sediment-laden runoff will prevent sedimentation of local watercourses. No effects expected. Overall, the scheme components would not adversely affect this WFD Element. Structure of the Riparian Zone WFD water body. No impact from the scheme is anticipated, since the main WFD water body reach is not involved in the scheme and no works would take place here. Supporting watercourses. The riparian zone during the construction phase should be protected by stand-off distances where possible (partially dictated for the purposes of water vole considerations also) to maintain a buffer strip. There will be some minor realignment of the Aldhurst Valley Stream to remove two sharp bends. The structure of the riparian zone, once the scheme is complete represents an improvement to the riparian zone on account of the additional diversity and extent of water related habitat. The presence of the basin discharge control structures within the riparian zone will have a net positive impact given the positive influence with regards control of basin level and discharge rate (and maintenance of new basin habitats). Overall, the scheme components would not adversely affect this WFD Element. Once the habitat scheme is completed, there is likely to be some benefit to the riparian zone. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 35 of 44

75 6.3.3 Chemical Status Table 6.4 Assessment of impact of proposed scheme on chemical elements WFD Element Discussion Priority Substances and Priority Hazardous Substances WFD water body and supporting watercourses. Current WFD status for Leiston Beck is Good for Priority Hazardous Substances (Priority Substances not assessed). No planned chemical discharges from scheme and disturbed land in agricultural use; it is assumed that any disturbed chemicals in the baseline environment will be negligible. Overall, the scheme components would not adversely affect this WFD Element WFD Mitigation Measures The 2009 RBMP reported a known morphological pressure (a physical modification) due to land drainage associated with the Cycle 1 water body (Leiston Beck and Minsmere Old River). All of those associated mitigation measures (as reported for the Cycle 1 water body) that are available to mitigate and reduce biological impacts from physical modification are considered here on the assumption that they remain applicable to the Cycle 2 Leiston Beck water body. Table 6.5 Assessment of impact of proposed scheme on those mitigation measures listed in the 2009 RBMP WFD Mitigation Measure Cycle 1 status (EA, 2009) Discussion Sediment management strategies (develop and revise) Appropriate techniques (invasive species) In Place In Place WFD water body and supporting watercourses. Scheme will not affect any existing sediment management strategies. Construction phase sediment control measures, including control of dewatering via a Discharge Permit, will ensure that sediment-laden runoff arising from the scheme is controlled. Once complete, the scheme will offer considerable advantage regarding control of sediment runoff, relative to that of riparian arable land-use with routine bare, ploughed surfaces. Overall, the scheme components would not adversely affect this WFD mitigation measure. WFD water body and supporting watercourses. Scheme will not affect any existing invasive species programmes. Species introductions associated with the scheme are designed to offer good quality, native, off-line habitat and will be carefully controlled. Overall, the scheme components would not adversely affect this WFD mitigation measure. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 36 of 44

76 Table 6.5 (continued) listed in the 2009 RBMP. Assessment of impact of proposed scheme on those mitigation measures WFD Mitigation Measure Cycle 1 status (EA, 2009) Discussion Appropriate timing (vegetation control) Appropriate vegetation control technique Selective vegetation control regime Appropriate channel maintenance strategies and techniques - minimise disturbance to channel bed and margins Improve floodplain connectivity Set-back embankments Flood bunds (earth banks, in place of floodwalls) In Place In Place In Place Not In Place Not In Place Not In Place Not In Place WFD water body and supporting watercourses. Scheme will not affect any existing vegetation control programmes. Reed cutting will be undertaken as per appropriate for given reed species. Scheme vegetation control should not affect in-channel macrophyte communities. Overall, the scheme components would not adversely affect this WFD mitigation measure. WFD water body and supporting watercourses. As above, scheme will not affect any existing vegetation control programmes. Reed cutting will be undertaken as per appropriate for given reed species. Scheme vegetation control should not affect in-channel macrophyte communities. Overall, the scheme components would not adversely affect this WFD mitigation measure. WFD water body and supporting watercourses. As above, scheme will not affect any existing vegetation control programmes. Reed cutting will be undertaken as per appropriate for given reed species. Scheme vegetation control should not affect in-channel macrophyte communities. Overall, the scheme components would not adversely affect this WFD mitigation measure. WFD water body and supporting watercourses. Scheme will not affect any existing channel maintenance programmes. Once complete the scheme will be offline (with exception of the basin overflow/discharge structures). Construction phase measures will ensure that minor realignment and disturbance to the banks of the Aldhurst Valley stream are kept to a minimum. Once complete, the scheme will require no disturbance to the channel bed and margins. Removal of the irrigation pond may overall return the watercourse to a more natural state, given that the pond area may be acting as a barrier to the establishment of instream communities. Overall, the scheme components would not adversely affect this WFD mitigation measure. WFD water body and supporting watercourses. There is potential for minor improvement with regards flood storage - thus a small improvement in terms of floodplain connectivity, which is in line with the aspiration of this mitigation measure. Overall, the scheme components would not adversely affect this WFD mitigation measure. WFD water body and supporting watercourses. The profile of the river banks is relatively natural in this part of the catchment with no flood embankments and the scheme will not affect the water body in this respect. This mitigation measure is more likely aimed at large portions of the Minsmere Old River which would benefit from set-back of embankments. Overall, the scheme components would not adversely affect this WFD mitigation measure. WFD water body and supporting watercourses. There are no flood walls or other flood infrastructure in this part of the catchment and the scheme will not introduce any such flood infrastructure that will constrain flood waters, or increase flood risk in the downstream water body. Overall, the scheme components would not adversely affect this WFD mitigation measure. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 37 of 44

77 6.4 Waveney and East Suffolk Chalk & Crag WFD Unit (ID: GB40501G400600) Chemical Elements Table 6.6 Assessment of impact of proposed scheme on groundwater chemical elements WFD Element Discussion Drinking Water Protected Area (DWPA) Even though the WFD unit (as a whole) contains a drinking water protected area, the baseline review has confirmed that there are no DWPAs, groundwater Source Protection Zones, SPZ (or SPZ catchments) in the vicinity of the proposed scheme. General Chemical Wetlands Groundwater will be utilised for the water supply to the proposed basins and to supplement watercourse flows via the abstraction borehole. Assuming good practice borehole installation (and other construction phase measures e.g. appropriate fuel storage and handling), there are no identified scheme components with the potential to introduce adverse chemical effects to groundwater. There are no statutory designated conservation sites within the development area. The lowering of the water table will be highly localised and flows in the Leiston Beck will be supplemented at Lovers Lane which will ensure no change to the water supply to the d/s Sizewell Belts. There is potential that d/s wetlands will be offered additional protection at times of low flow/drought given that surface watercourses (which may be assumed to have a high degree of groundwater connectivity) may be supported with outflows from the new basins. The entire Aldhurst Farm Habitat Creation scheme has been designed, in consultation with the statutory bodies as well as non-governmental organisations, to offer good quality wetland habitat. Saline Intrusion Groundwater flow below the valley is to the east i.e. toward the coast. There would be no increased risk of saline intrusion compared to the baseline environment. The groundwater inputs to the finished basins would be passive (i.e. not actively pumped) and outflows, although managed locally to some extent to control water level, will spill back into the local watercourses which are in connectivity with the groundwater i.e. there will be no net removal of groundwater associated with the basins. The new abstraction borehole(s) which will be used to ensure that flows d/s of Lovers Lane are maintained at 11l/s will be limited in supply volume to the licensed volume associated with the existing spray irrigation licence. Thus, there would be no net change, relative to the baseline environment. There will be no increase in potential for saline intrusion. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 38 of 44

78 6.4.2 Quantitative Elements Table 6.7 Assessment of impact of proposed scheme on groundwater quantitative elements WFD Element Discussion Groundwater Dependent Terrestrial Ecosystems (GWDTEs) No statutory designated conservation sites are present within the scheme area. The scheme design measures will ensure that d/s areas are not impacted with regards groundwater (or surface water) and thus there will be no effect on GWDTEs. There is potential that d/s wetlands will be offered additional protection at times of low flow/drought given that surface watercourses (which may be assumed to have a high degree of groundwater connectivity) may be supported with outflows from the new basins. Surface Waters The scheme has been designed in order to ensure groundwater supply to the associated Leiston Beck WFD water body is not adversely affected. Up to two new abstraction boreholes will ensure that flows in Leiston Beck at Lovers Lane are maintained at 11l/s. Localised reduction in baseflow contribution to the onsite watercourses (e.g. Aldhurst Valley Stream), to allow groundwater supply to the new basins will not propagate beyond the site boundary. Considerable positive benefit to the surface waters of the proposed scheme i.e. the new wetlands, will be afforded. Water balance (sustainable abstractions) Groundwater abstractions (and groundwater interactions) have been designed such that there are no changes relative to the baseline environment beyond the site boundary and therefore the water body and regional scale water balance is not affected. Thus, other existing water users would not be derogated by the existence of the proposed scheme. The new borehole will reintroduce water into the surface water catchment -which is in continuity with the groundwater- as opposed to loss of groundwater resource from the spray irrigation licence (under current baseline conditions). Saline intrusion Groundwater flow below the valley is to the east i.e. toward the coast. There would be no increased risk of saline intrusion compared to the baseline environment. The groundwater inputs to the finished basins would be passive (i.e. not actively pumped) and outflows, although managed locally to some extent to control water level, will spill back into the local watercourses which are in connectivity with the groundwater i.e. there will be no net removal of groundwater associated with the basins. The new abstraction borehole(s) which will be used to ensure that flows d/s of Lovers Lane are maintained at 11l/s will be limited in supply volume to the licensed volume associated with the existing spray irrigation licence. Thus, there would be no net change, relative to the baseline environment. There will be no increase in potential for saline intrusion. 6.5 Overall WFD Status The comparison of the scheme components against the WFD elements for each WFD unit has indicated that the scheme would not result in a derogation of any of the elements, or therefore the overall WFD status for any WFD unit. The site is located upstream of the main-river Leiston Beck WFD river waterbody and no elements of the scheme directly interact or impact upon this downstream reach. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 39 of 44

79 Where some short reaches of the small watercourses within the site boundary (upstream of the main-river Leiston Beck WFD river waterbody) may experience a reduced baseflow on account of the lowered water table, the scheme is designed such that the new basins overspill into these watercourses and downstream surface water flows will be supplemented by up to two new groundwater abstraction borehole (as conditions require periodically). In this way there will be no decrease in the flows downstream of Lovers Lane and no net quantitative loss of groundwater (relative to baseline and given that the surface watercourses are in good hydraulic connectivity with the underlying aquifer). The proposed scheme, in addition to those inherent benefits associated with the habitat creation area, offers a number of potential minor ecological and flow benefits to the wider WFD waterbody, such as the potential for some flow augmentation during periods of low flow/drought, which not only offers potential quantitative benefit but also offers qualitative benefit (offering additional dilution to discharges from the WWTW, which represents the greatest potential point source influence on the water quality of the Leiston Beck WFD waterbody). The EA have assessed (via their WFD RBMP investigations) that the Leiston Beck waterbody is currently failing to meet Good Potential primarily on the basis of Phosphate concentrations - which are currently (2013 data) consistent with Bad status conditions. The proposed scheme may result in a small change in phosphate concentrations (see Table 6.2) during the construction stage - measures such as water quality monitoring, lowering of the water table (to enable dry working) and appropriate management and placement of soils will ensure that any changes in phosphate are managed. Any phosphate inputs from the proposed scheme are considered negligible when compared to the contributory point source of the Leiston WWTW which discharges to the Leiston Beck effectively at the same location as the proposed scheme. When the scheme is complete, nutrient uptake by the reedbeds will likely reduce potential phosphate concentrations and offer a potential benefit relative to the baseline environment (runoff from agricultural and bare unvegetated fields during at least part of the year) assuming reeds are periodically removed via harvesting. Augmentation in the site watercourses at times of low flow (relative to baseline conditions) may also provide potential dilution of downstream phosphate concentrations deriving from STW discharges at times of low flow/drought. A number of further potential local improvements will collectively help to improve the status of the overall waterbody; these include: increased nursery habitat for fish and habitat for eel (WFD biology element); increased diversity and extent of habitat for macro-invertebrates (WFD biology element); improved and expanded potential for macrophytes (WFD biology element); NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 40 of 44

80 improvements to the river connectivity due to expansion of aquatic habitat and provision of eel passes (WFD hydromorphological element); improvements to all WFD groundwater quantitative elements at times of low flow/drought as a result of potential augmentation from basins. Where potential adverse effects have been identified with regards to the small watercourses within the site boundary (upstream of the main-river Leiston Beck WFD river water body), the scheme design (which has adopted an iterative approach) has allowed for control measures to be incorporated and these have been presented both within the discussion of scheme components (see Table 6.1) and within the consideration of WFD units and their contributory WFD elements (see Table 6.2 to Table 6.7). Consideration of each element determines that the scheme would not reduce the ability of the Leiston Beck WFD water body or the Waveney and East Suffolk Chalk & Crag groundwater WFD Unit to meet improved status in the future. The recent publication of the Mitigation Measures Assessment (MMA) results (Cycle 2 draft) confirms that the Leiston Beck MMA is currently at Moderate or less. The specific Cycle 2 mitigation measures have yet to be published, however the Environment Agency has confirmed that these are very likely to be the same as for the Cycle 1 waterbody (GB ) those currently not in place are: Improve floodplain connectivity; Set-back embankments; Flood bunds (earth bunds in place of flood walls); Appropriate channel maintenance strategies and techniques-minimise disturbance to channel bed and margins. Given the nature of the proposed scheme, its location in the upper surface water catchment (above the main river) and its design for the benefit of habitat creation it is deemed that the scheme would have no impact on the implementation of these WFD mitigation measures. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 41 of 44

81 7 CONCLUSION This WFD assessment for the proposed Aldhurst Farm Habitat Creation scheme indicates that the scheme, as designed, would not result in degradation of the existing WFD status for the two WFD water bodies (one surface water body and one groundwater body). The component WFD elements (biological, physico-chemical, hydromorphology and chemical) for the surface WFD water body unit, and quantitative and chemical for the groundwater WFD unit, have been fully assessed for impacts against the scheme proposals. Identified effects are considered to be highly local in scale, and relate, for example, to the required localised lowering of the water table in the vicinity of the new basins and the potential for low flow augmentation. This report has identified a range of effects of the proposals, some negative, and some positive. The negative effects relate mainly to potential construction phase effects which could potentially (over a short time period) affect WFD supporting elements. However, control measures including surface water drainage control and appropriate construction methods would mitigate any effects to an acceptable level. The scheme also contains a number of potential local improvements to the water environment which collectively will improve the WFD environment, for example through improvements to floodplain connectivity and creation of new high value aquatic habitat, which is also specifically designed to be accessible for eels. It is considered that overall the positive impacts of the proposed works outweigh the localised (and temporary) potential negative impacts. The scheme components and measures identified would ensure that none of the WFD elements are degraded resulting in no reduction in overall WFD status. Further, it is considered that the proposals would not conflict with any future works to implement environmental improvement (HMWB mitigation measures) that may be identified for the Leiston Beck WFD water body during Cycle 2. In some cases there will be local benefit with regards the WFD mitigation measures (assuming mitigation measures for the Cycle 1 water body are taken forward) for example with regards restoration of a more natural channel form and an increase in floodplain connectivity. As the changes on the WFD water body units associated with the scheme are considered to be of either no impact or slightly beneficial, no impacts on the downstream coastal WFD water body unit is expected. As the scheme includes design measures and mitigation to manage impacts on the water environment within the site boundary, the scheme is not expected to act in combination with other planned developments to cause an overall deterioration in WFD status or prevent the achievement of good ecological status/potential. The scheme is therefore considered to be compliant with the WFD. The scheme would not cause degradation of any WFD elements, or limit the potential for future improvements in these WFD elements. No further assessment is therefore proposed. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 42 of 44

82 8 REFERENCES AMEC (2014a). Aldhurst Farm Habitat Creation Scheme, SSSI Replacement Habitat Feasibility and Conceptual Design Report. Reference C-001i3 Issue 03 BPE, dated 15 April AMEC (2014b). Aldhurst Farm Habitat Creation Scheme, Design Statement, AMEC (2014c). Aldhurst Farm Habitat Creation Scheme, Construction Method Strategy, AMEC (2014d). Aldhurst Farm Habitat Creation Scheme, Flood Risk Assessment, AMEC (2014d). Aldhurst Farm Habitat Creation Scheme, Materials Management Plan. CIRIA (2010). Environmental good practice on site guide (C692). Edited by Iain Audus, Philip Charles, Simon Evans, London, Defra (2014). Water Framework Directive implementation in England and Wales: new and updated standards to protect the water environment, May Environment Agency (2009). River Basin Management Plan: Anglian River Basin District. Environment Agency, Bristol, December Environment Agency (2010) unpublished. Assessing new modifications for compliance with WFD: detailed supplementary guidance (488_10_SD01), 09/11/10. Environment Agency (2011a). Method statement for the classification of surface water bodies. Environment Agency (2011b) unpublished. Assessing impacts on water bodies in planning; Quick guide (614_11), 20/05/2011. Environment Agency (2014a). Consultation response addressed to Dr Stephen Mannings, dated 23 May Ref AE/2013/116806/04. Environment Agency (draft - unpublished). Interim Water Framework Directive Assessment and Statement of Compliance. Environment Agency (2014b). Anglian River Basin District: A consultation on the draft update to the river basin management plan. Part 2: River basin management planning overview and additional information. Environment Agency, Deanery Road, Bristol, NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 43 of 44

83 Environment Agency (2014c). Letter addressed to Dr Stephen Mannings, dated 3 November 2014, from Neil Dinwiddie, Project Co-ordinator Sizewell C Nuclear New Build. EA ref AE/2013/116806/07 NIEA (2012). Carrying out a Water Framework Directive Assessment. Assessment on EIA Developments, Northern Ireland Environment Agency, March Royal HaskoningDHV, (2013). Sizewell Marshes SSSI Replacement Habitat Feasibility & Conceptual Design Report. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London Page 44 of 44

84 NNB-209-REP Version 1.0 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION: ENVIRONMENTAL ASSESSMENT APPENDIX B HABITAT REGULATIONS ASSESSMENT NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 2.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 16 of 17

85 ALDHURST FARM HABITAT CREATION SCHEME SHADOW HABITATS REGULATIONS ASSESSMENT SCREENING REPORT NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 1 of 30

86 TABLE OF CONTENTS 1 INTRODUCTION Purpose Background Procedure and Process OVERVIEW OF THE SCHEME BASELINE CONDITIONS Overview Hydrology and hydrogeology Ecology PROJECT EFFECTS Introduction Construction Management of construction activities Dust, noise and vibration Hydrology and hydrogeology Permitting and Monitoring Operational Groundwater and surface water Ecology Permitting and monitoring SCREENING AND DETERMINATION OF LIKELY SIGNIFICANT EFFECT Introduction Identification of relevant European sites Effects of the Scheme on Designated European Sites Habitat loss and fragmentation Hydrology and Hydrogeology Air quality Disturbance In-combination effects SUMMARY REFERENCES NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 2 of 30

87 LIST OF FIGURES Figure 1: Site Location Figure 2: European sites located within 10km of the proposed application site at Aldhurst Farm LIST OF TABLES Table 1: Summary of potential influence of the Aldhurst Farm Habitat Creation Scheme on European Sites within 10km and conclusions on potential for Likely Significant Effect NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 3 of 30

88 1 INTRODUCTION 1.1 Purpose This document constitutes a shadow screening of the proposed Aldhurst Farm Habitat Creation Scheme in respect of the requirements of The Conservation of Habitats and Species Regulations 2010 (Habitats Regulations). The report sets out information to enable the Competent Authorities to determine whether the scheme could give rise to a likely significant effect on a designated European site in determination of applications for planning consent, and environmental permits/consents. For this purpose the report provides: A description of the proposed scheme; Identifies potential effects that could influence relevant European designated sites; An assessment of the effects on European sites; and A screening conclusion in respect of likely significant effect. 1.2 Background The Habitats Directive protects habitats and species of European nature conservation importance. Together with Council Directive (2009/147/EC) on the conservation of wild birds (the Birds Directive ), the Habitats Directive establishes a network of internationally important sites designated for their ecological status. Special Areas of Conservation (SACs) and Sites of Community Importance (SCIs) are designated under the Habitats Directive and promote the protection of flora, fauna and habitats. Special Protection Areas (SPAs) are designated under the Birds Directive in order to protect rare, vulnerable and migratory birds. These sites combine to create a Europe-wide Natura 2000 network of designated sites, which are hereafter referred to as European sites. The Conservation of Habitats and Species Regulations 2010 (Habitats Regulations) incorporate all SPAs into the definition of European sites and, consequently, the protections afforded to European sites under the Habitats Directive apply to SPAs designated under the Birds Directive. In addition to sites designated under European nature conservation legislation, UK Government policy (ODPM Circular 06/2005) states that internationally important wetlands designated under the Ramsar Convention 1971 (Ramsar sites) are afforded the same protection as SPAs and SACs for the purpose of considering development proposals that may affect them. 1.3 Procedure and Process Regulation 61 of the Habitats Regulations defines the procedure for the assessment of the implications of plans or projects on European sites. Under this Regulation, if a proposed development is not connected with site management and is likely to significantly affect the designated site, the competent authority must undertake an appropriate assessment (Regulation 61(1)). In this respect, the Aldhurst Farm Habitat Creation Scheme is not connected to the management of any designated European site. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 4 of 30

89 Guidance (EC 2000, IPC 2011) on undertaking assessment of plans or projects that may impact upon designated European sites recommends a staged approach to the assessment process. The generalised steps utilised are set out below: Screening (Step 1): The process of identifying potentially relevant European sites and the likely impacts of a project upon the designated features of a European site, either alone or in combination with other plans and projects, and considering whether the impacts are likely to be significant. Appropriate Assessment (Step 2): The consideration of the impacts on the integrity of the European site, either alone or in combination with other plans and projects, with regard to the site s structure and function and its conservation objectives. Where there are adverse impacts, an assessment of mitigation options is carried out to determine adverse effect on the integrity of the site. If these mitigation options cannot avoid adverse effects then consent can only be given if stages 3 and 4 are followed. Assessment of Alternative Solutions (Step 3): Examining alternative ways of achieving the objectives of the project to establish whether there are solutions that would avoid or have a lesser effect on European sites. Imperative Reasons of Overriding Public Interest (IROPI) (Step 4): This is the assessment step where no alternative solution exists and where adverse impacts remain. The process to assess whether the development is necessary for IROPI and, if so, the potential compensatory measures needed to maintain the overall coherence of the site or integrity of the European site network. All four stages of the process are referred to cumulatively as the Habitats Regulations Assessment (HRA), to clearly distinguish the whole process from the step within it referred to as the Appropriate Assessment. In the determination of likely significant effect, guidance has been provided in English Nature s Habitat Regulations Guidance Note 3 (HRGN3) The Determination of Likely Significant Effect under the Habitats Regulations (English Nature 1999). This involves a preliminary consideration of whether a qualifying feature is likely to be directly or indirectly affected (in which case there is a presumption that a significant effect is likely). In such a case, a fuller consideration should then be applied, using further analysis and information, to confirm and justify the presence or absence of likely significant effect. Appropriate Assessment is needed in cases where a likely significant effect is identified. A likely significant effect is, in this context, any effect that may be reasonably predicted as a consequence of a plan or project that may affect the conservation objectives of the features for which the site was designated, but excluding trivial or inconsequential effects. This report provides information to enable the competent authority to undertake Step 1 in the HRA process and determine whether any further assessment (i.e. Step 2 and onwards) is required in respect of the potential effects of the project on designated European nature conservation interests. 2 OVERVIEW OF THE SCHEME EDF Energy is proposing to convert a 67ha arable farm in Leiston into wetland and terrestrial habitat. The proposed scheme centres on the creation of wetland habitat NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 5 of 30

90 comprising lowland ditches, reedbed and open water which will occupy approximately 6 ha of low-lying land alongside two existing watercourses. Figure 1 shows the site location. The wetland would be created within groundwater basins that would be excavated to a sufficient depth to ensure that they remain permanently wet, even under drought conditions. This is important to create sustainable wetland. These wetland habitats would grade into an extensive area of drier, terrestrial habitats, comprising a mosaic of neutral and acid grassland, heathland, scrub and occasional scattered trees across the remainder of the site. A full description of the proposed scheme is provided in the Design Statement that supports the planning application. The overall scheme objectives are to: Create and maintain approximately 5 ha of wet reed habitat, incorporating between 20-30% open water habitat and approximately 5-15% of later succession habitats that support a characteristic assemblage of reedbed plant and animal species; Create and maintain approximately 0.8 ha of reed based tall herb fen that supports a characteristic assemblage of tall herb fen plant and animal species; Create and maintain approximately 2km of perimeter ditch habitat that supports a diverse vascular plant assemblage and a range of fauna characteristic of lowland ditch habitat; Create and maintain a mosaic of neutral and acid grassland / heathland, scrub and scattered trees transitioning from the perimeter ditches and across the wider site; Ensure no net loss of biodiversity on the Aldhurst Farm site as a result of the habitat creation scheme, and maximize the floral and faunal biodiversity of the created and retained habitats; In the longer term, enhance ecological connectivity between Aldhurst Farm and Sizewell Marshes SSSI beneath Lover s Lane; Ensure that the scheme landscape reflects the distinctive land-use and vegetation typologies of the adjacent Estate Sandlands and Coastal Levels character types; and In the longer term, open up parts of the site for quiet public recreation, in a manner that does not compromise the above habitat management objectives. Construction works to deliver the habitat creation proposals are anticipated to be undertaken over a period of approximately 8 months between March - October. The main construction activities are detailed in the Design Statement and the Construction Management Strategy that support the planning application, and in summary would comprise: Preliminary works including establishment of site security, site entrances, temporary construction compound, tree protection and removal, measures to protect users of public footpaths, construction of temporary ditch crossings, trial excavations and ditch clearance. Excavation of groundwater basins including lowering of ground levels, excavation of pools and ditches, construction of control structures and transport of excavated soil materials for reuse. Bulk excavations would be achieved largely through the use of conventional earthmoving plant (low ground pressure excavators and dump trucks). Some elements of the work may require dry working with the need to undertake dewatering. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 6 of 30

91 Construction of control structures - Control structures would be constructed between each groundwater basin and the existing water course (Aldhurst Stream Valley or Leiston Beck) to allow water levels to be managed. Soil management - the creation of the four groundwater basins and associated ditches would result in the excavation of approximately 83,000m 3 of soil. This excavated soil would be beneficially reused within the wider Aldhurst Farm site as a soil conditioner as part of wider landscape creation. The proposed management of the excavated soil and its reuse elsewhere within the site is described within the Materials Management Plan (MMP), and would comprise: Soil excavation from the groundwater basins direct into an articulated dump truck (ADT) or similar plant; Movement direct to the designated application area/subarea; End tip; Placement in a layer of compacted (i.e. tracked) 150mm thickness (peat or clay) or 200 to 250mm for topsoil and sand by a low ground pressure dozer (uncompacted thickness to be determined by field trials); Mixing the placed material (peat) to a depth of 300mm below existing ground level; Harrowing and seeding as defined in the Ecology & Landscape Management Plan. Borehole decommissioning and relocation - The existing spray irrigation licence comprises approximately 15 shallow boreholes. The associated pump house, boreholes and pipework would be removed. Up to two new boreholes would be constructed outside of the valley to provide stream support to Leiston drain should its flow fall below 11l/s at Lover s Lane, as may occur occasionally under drought conditions. This measure has been agreed with stakeholders to protect the integrity of Sizewell Marshes SSSI located downstream; Reed planting - Reeds for the groundwater basins would be sourced from commercially available nursery stock and planting would be undertaken in late summer/ early autumn. In addition, ditch slubbings be used to plant the perimeter ditches in autumn. 3 BASELINE CONDITIONS 3.1 Overview The Aldhurst Farm site is bounded by Lover s Lane to the north and east; by Valley Road to the south-east; and residential areas in Leiston and along the B1122 to the south and west, respectively (see Figure 1). The site is not a designated nature conservation site or within any landscape designation, however it is located immediately to the west of Sizewell Marshes Site of Special Scientific Interest (SSSI) and the Suffolk Coast and Heaths Area of Outstanding Natural Beauty (AONB). The Site is in arable farming use, comprising a series of fields, with access tracks, boundary hedgerows and small plantation woodland and shelter belts (mainly comprising mature hybrid poplar). NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 7 of 30

92 The environmental aspects relevant to assessing potential effects of the proposed scheme on European sites are local hydrological and hydrogeological conditions and ecology, where are summarised below. Further details on hydrology and hydrogeology can be found in the Design Statement, specifically in the Feasibility & Conceptual Design Report included at Appendix A of the Statement. Baseline ecological resources are detailed in the Ecological Appraisal at Appendix A Aldhurst Farm Habitat Creation Baseline Ecology Report. 3.2 Hydrology and hydrogeology As illustrated in Figures 1 and 2, the Site occupies a west-east aligned valley drained by a small watercourse, the Aldhurst Valley Stream which discharges to Leiston Beck (called Leiston Drain immediately downstream of the Site). Leiston Beck receives treated sewage effluent from the adjacent Leiston Waste Water Treatment Works (Leiston WWTW) which discharges into a drain that feeds Leiston Beck. Leiston Beck routes around the northern side of Sizewell Marshes SSSI and discharges to the North Sea via Minsmere Sluice. The surface water catchment of Leiston Beck (to Lover s Lane) covers about 4.62 km 2. Surface water monitoring carried out between October 2010 and October 2012 in the upper reaches of the Aldhurst Farm site, upstream of the former irrigation pond, recorded flows from less than 1 l/s to 7 l/s but were generally low (less than 1 l/s) with higher flows being associated with rainfall events. Monitoring over the same period in Leiston Beck, in the lower reaches of the site just upstream of Lover s Lane, recorded flows of 20 to 60 l/s and indicated a significant gain in flows as a result of the WWTW discharge and groundwater accretion. More recent spot flow gauging in March 2014 has confirmed this picture. Daily flow data provided by the Environment Agency for the period 2009 to 2012 indicate that flow from the WWTW is, on average, 18 l/s, showing a typical diurnal pattern. Environment Agency records show that the Qn95 flow within Leiston Beck at Lover s Lane is 11 l/s. Bed elevations in the watercourses fall from 5.5m AOD in the Aldhurst Valley Stream in the extreme west of the site to -1m AOD in the Leiston Beck at Lover s Lane. The channel bed elevations are generally 1-1.5m lower than the adjacent valley floor ground levels and stream levels are also below groundwater levels. This is important to the scheme design as this would allow water levels in the basins to be managed by draining to surface water. The majority of the site is underlain by Quaternary sands and gravels of the Lowestoft Formation. A narrow band of Lowestoft Till outcrops on the high ground to the south of the valley. Peat deposits are present within the majority of the valley floor, being deepest (between 0.5 and 1m thick) in the middle and lower reaches of the valley. The solid geology below the site is the Quaternary Crag Formation, comprising mainly fine-grained buff to brown, locally shelly, micaceous sands and flint gravels up to 60m thick. The Crag Formation is classified by the Environment Agency as a Principal Aquifer. The Lowestroft Sands and Gravels are classified as a Secondary A Aquifer. Groundwater flow below the valley is to the east. Groundwater levels fall from 3.5 maod (3mbgl) at the western edge of the valley to 1.3mAOD (0.2mbgl) at the eastern edge of the valley. Groundwater levels in the overlying sands and gravels are similar (within 0.05m) to the underlying Crag indicating good hydraulic continuity between these aquifers. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 8 of 30

93 Seasonal variation in groundwater levels in the valley bottom is relatively subdued, at around 0.25m; greater variation (around 0.5m) is seen in at the top of the valley. There are a number of licensed groundwater abstractions in the site s vicinity. There is one relatively small abstraction within the site boundary which comprises a series of 15 well points and is used for spray irrigation in the period April September. There are also two public water supply abstractions Leiston PWS located 2km south-west of the site and Coldfair Green PWS located 3km south-west of the site which both have associated compensation discharges. The Leiston PWS Licence requires a discharge of up to 570 m 3 /day to Leiston Beck at Lover s Lane when directed to do so by the Environment Agency. Modelled groundwater levels have been obtained from the Environment Agency regional groundwater flow model. These levels have been inspected to assess groundwater levels under drought and theoretical Full Licensed (FL) abstraction conditions (where all abstractions within the potential affected environment are operating at maximum abstraction quantities throughout the modelled time series). These modelled levels indicate that groundwater levels could be approximately 0.4 m lower than observed water levels in Surface water sampling in the Leiston Beck next to Lover s Lane indicates that water quality is impacted by the WWTW with elevated concentrations of nitrogen (nitrate), phosphorus and potassium. ph values for surface water varied from 7.5 to 8.8. Dissolved oxygen concentrations in surface water were also low and electrical conductivity is low and typically less than 2500 us/cm. Leiston Drain downstream of Lover s Lane is classified as moderate ecological quality based on dissolved oxygen and physico-chemical parameters. Groundwater samples (from the eastern edge of valley) are characterised by chloride concentrations typically about 100 mg/l and sulphate in the range 100 to 200 mg/l. Samples from a borehole at the top of the valley were characterised by variable high chloride and sodium concentrations which indicate drainage of road run- off to groundwater. The ph for groundwater typically ranges from 6.5 to 8.6 (mean 7.3). Overall the groundwater chemistry is suitable for reed beds. 3.3 Ecology Surveys of the Aldhurst farm site have indicated that the following species or species groups of nature conservation value are present: Water vole present in low numbers in the lower reaches of the Aldhurst Valley Stream and upper reaches of Leiston Beck; Otter Occasional signs found previously on Leiston Beck; Reptiles (Common lizard, grass snake, adder) - All three species present in low numbers in the proposed wetland area, whilst common lizard and grass snake are present on the restored landfill in the south centre of the site; Breeding birds of arable, field margins, hedgerows and trees assemblage present typical of arable landscape but contains nine BAP or red list species on conservation concern including skylark, dunnock, song thrush, starling, house sparrow, linnet, bullfinch, yellowhammer and house sparrow; Wintering birds of water margins/ditches, arable, field margins, hedgerows and trees NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 9 of 30

94 assemblage present typical of arable landscape and contains similar species to those found to be breed on site. The wider site supported only low numbers of winter passerines, lapwings, gulls and winter corvids because of the general lack of suitable foraging habitat for these species and no large concentrations of birds were recorded foraging in the fields however species of interest, such as snipe, teal, water rail and little egret were recorded associated with the ditches and where water had spilled onto fields in the lower valley; and Bats - 10 species recorded foraging/commuting over the site. No confirmed roosts, although there are mature trees with potential. Sizewell Marshes SSSI is located 10m east of the site boundary and is 105.4ha in size. Large areas of lowland and unimproved fen meadows, reedbed and lowland ditches are present. It supports a diverse assemblage of invertebrates and vascular plants. It also supports breeding birds of national significance, including shoveler, gadwall, teal, snipe and lapwing, typical of wet grassland and associated habitats, although based on information from Natural England it is believed that the breeding bird assemblage is sub-optimal. 4 PROJECT EFFECTS 4.1 Introduction EDF Energy has undertaken environmental studies to inform a thorough understanding of baseline conditions, to inform the design of the scheme and to understand and manage any possible adverse effects (and maximise opportunities for environmental enhancement). Extensive consultation has been undertaken on the proposals from early conceptual and feasibility design of the wetland habitat to the detailed design, wider landscaping proposals and management of the construction of the habitats through to their longer-term establishment. The design proposals and management requirements have been developed with advice received through consultation with a number of stakeholders including Suffolk Coastal District Council, Suffolk County Council, the Environment Agency, Natural England, Suffolk Wildlife Trust and the RSPB. The scope of the consultation was limited to advice on habitat creation and conservation management. 4.2 Construction Management of construction activities A description of the construction works and mitigation measures that would be used to avoid and reduce potential adverse environmental effects are set out in the Construction Management Strategy. This includes: Use of trial excavations during the preliminary works, including o A dewatering trial to optimize dewatering arrangements; o Optimisation of the bulk excavation methods for the basins and ditches; o Confirming the appropriate level of finish/detail to the final excavations to NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 10 of 30

95 ensure the best ecological outcomes from the created habitats; o Trial the method for soil spreading and incorporation within the plough layer to optimise reuse of peat and ensure that the application method deliver an appropriate reduction in soil ph. Vegetation removal and desilting works along the WWTW drain and Leiston beck between the sewage treatment works and Lover s Lane to improve flow conveyance within this currently heavily silted ditch through the site; Adoption of Environment Agency Pollution Prevention Guidance Notes (PPGs) and other relevant industry guidelines including CIRIA guidance to avoid environmental pollution (especially water pollution) and ensure appropriate waste management; Dust, noise and vibration management to minimise off-site emissions; Measures to protect existing ecology both on and off-site within Sizewell Marshes SSSI (which are set out in detail in Appendix E Ecology Mitigation Plan of the Construction Management Strategy). In particular, measures would be adopted to maintain water supplies to Sizewell Marshes SSSI during the construction phase through the optimisation of groundwater dewatering, including use of recharge ditch (or ditches) at the downstream end of the site if groundwater monitoring indicates this is required Dust, noise and vibration Temporary disturbance from noise and vibration could arise during the construction phase to ecological interests e.g. breeding birds, water voles and reptiles. The earth excavation works and movement of vehicles around the site also have the potential to generate airborne dust. Subject to the adoption of the mitigation measures set out in the Construction Management Strategy to control emissions, no adverse ecological effects are predicted. Any potential residual effects would not be spatially extensive and would effectively be localised to Aldhurst Farm and its immediate environs. The short duration of the construction works (up to 8 months approximately) would also preclude any long-term and lasting disturbance effects arising. The proximity of the scheme to existing sources of disturbance e.g. Lover s Lane, the nearby waste recycling centre and the fact that existing agricultural activities on the site are in themselves disturbing, indicates that it is very unlikely that any such residual disturbance effects would be ecologically significant in comparison to the existing baseline. The works are also planned to be undertaken between March and October, and therefore outside the main period in which wintering birds might be present on or around the site Hydrology and hydrogeology Surface water and groundwater would be managed to ensure water quality is suitable for discharge to surface water and for reed bed planting. Details of surface water and groundwater management are described fully in the Construction Management Strategy, but the main elements are: NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 11 of 30

96 Ditch clearance downstream of Leiston WWTW and completion of a trial excavation to improve flow conveyance and optimise the dewatering strategy/soil spreading, among other things. These activities would be carried out during the preliminary works phase, ahead of the main works, as previously described; Various controls relating to the use of excavated peat (and other excavated soils) for soil conditioning across the wider site, which would be carried out in accordance with guidance in the CL:AIRE Definition of Waste: Development Industry Code of Practice (DoWCoP) (see also the detailed control measures set out in Section 5.12 of the Design Statement which accompanies the planning application). This would ensure that surface water and groundwater resources would be protected; Control of discharges of dewatering water into Leiston Beck, both in terms of flow and water quality. This would be facilitated by construction of a temporary lagoon in Basin A and/or pumping between basins. Treatment would include suspended sediment settlement and ph control, as necessary, and surface water monitoring of the receptors would be carried out at upstream and downstream locations; and Measures to prevent significant drawdown of groundwater beneath Sizewell Marshes SSSI during dewatering of the groundwater basins (see below). To limit the potential for groundwater drawdown beneath the adjacent Sizewell Marshes SSSI, it is envisaged that groundwater levels would be temporarily lowered to allow dry working of the wet reedbed areas and to facilitate overdigging and replacement of peat, where necessary. It is envisaged that the perimeter ditches and open water pools, which would be deeper, would be wet worked. Therefore the depth of lowering of groundwater levels within the groundwater basins is likely to be restricted to between 0.5m and 1.5m. A detailed assessment has been made of the likely effects of this drawdown on surface water and groundwater levels off-site, within Sizewell Marshes SSSI (see the Hydrology Technical Note included as Appendix B of the Design Statement). Briefly, this assessment demonstrates that dewatering should not affect surface water flows in Leiston Drain, although some localised groundwater drawdown of up to around 0.8m may occur beneath the western part of the SSSI. The assessment indicates that there are not likely to be any effects on groundwater levels beyond approximately 250m of the site. Any such effect would be temporary as groundwater levels would rebound to baseline levels within a month of dewatering ending and the basins would only be dewatered for around six weeks. In order to protect the nearest groundwater level-sensitive designated feature within Sizewell Marshes SSSI (the fen meadow community M22 Juncus subnodulosus-cirsium palustre which is located approximately 175m from the edge of the Aldhurst farm site at its closest point) it is intended to undertake groundwater monitoring downstream of the basins and if this indicates any potential effect on the fen meadow, a recharge ditch (or ditches) would be excavated downstream of the basins to maintain groundwater levels off-site. In summary, the construction works would be managed through the adoption of good practice measures. This would include excavation works being undertaken within the basins, managed dewatering between basins (in the event that this is required over the short term to allow access for excavation plant and equipment) and the use of control structures within connections between the basins and watercourses to allow flow/quality monitoring prior to discharge. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 12 of 30

97 It is considered that the adoption of the measures described above (together with adherence to permit conditions, see below) would avoid affecting downstream water flows and quality within Leiston Drain (and Sizewell Marshes SSSI) Permitting and Monitoring Construction of the scheme would be carried out in accordance with the following permits: Environmental Permit to cover the discharge of water from the dewatering operation during the construction works to the Aldhurst Valley Stream or Leiston Beck. This permit would define upper limits for the volume and quality of the discharge; Internal Drainage Board Consent to cover construction of the control structures, realignment of the Aldhurst Valley Stream and any works within 9m of the water courses; and Water resources consent for drilling and testing of the stream support borehole. Monitoring would be undertaken to ensure compliance with environmental permits and to confirm maintenance of water levels, flow and quality in the Leiston Beck. As a minimum monitoring would comprise: Measurement of the volume (daily) of construction discharge to the Aldhurst Valley Stream and Leiston Beck; Measurement of the water quality (daily) of the construction discharge for the following parameters: ph, dissolved oxygen, electrical conductivity, ammoniacal nitrogen and suspended solids. Samples would also be obtained (weekly) for laboratory analysis for sulphate, heavy metals, phosphorous and ammoniacal nitrogen. Water quality measurements would also be undertaken within the basins and of pumped water; Measurement of water levels and flow (daily) in the Leiston Beck upstream of Lovers Lane; and Monitoring of groundwater levels at the eastern boundary of the site to confirm that dewatering is not adversely impacting water levels below Sizewell Marshes. The monitoring data would need to be reviewed to confirm the effectiveness of management measures (e.g. water treatment) or the need to implement additional measures including temporarily ceasing dewatering. 4.3 Operational Groundwater and surface water Detailed hydrological and hydrogeological studies have been undertaken which have informed the design of the reedbed and lowland ditch habitat. These have been carried out in consultation with stakeholders, including the Environment Agency and Natural England. Both stakeholders are satisfied that these studies provide a sufficiently comprehensive and detailed analysis of the site s prevailing hydrological and hydrogeological conditions. Control structures and stop boards will be designed and constructed to allow water levels in NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 13 of 30

98 the four basins to be managed. Water level management will be undertaken as necessary. Water balance calculations indicate that evapo-transpiration from the groundwater basins could result in an evaporative loss of 1 to 3 l/s in the period June to August and there is therefore a potential for flow in the Leiston Beck to fall below 11 l/s under drought conditions, although for the majority of years flow is expected to be above this level. It has been agreed with the Environment Agency, that as a precaution, flow should not fall below 11 l/s in Leiston Beck at Lover s Lane. A flow gauging station has been constructed, just upstream of Lovers Lane, and is maintained by EDF Energy. This station has a telemetry system and the flow data would be provided to the Environment Agency. In the unlikely situation where flows fall below 11/s, abstraction would take place from the stream support borehole with discharge to the Leiston Beck. The abstraction licence would allow an abstraction of up to 3 l/s to be maintained over a period of 100 days per annum, with flexibility of pumping up to 10 l/s over short periods, if required. It is not therefore considered that the scheme would have a significant effect on surface water flows within Leiston Drain downstream of the site, even under drought conditions Ecology The principal environmental effect would be a permanent ecological enhancement due to creation of up to 67 ha of semi-natural habitat on arable land which is currently of low ecological (and biodiversity) interest. Many of the proposed habitats, including reedbeds, are listed as Suffolk Priority Biodiversity Action Plan Habitats. There are some existing ecological features within the Site, notably water voles within the ditches; and reptiles (slow worm and adder) within the field margins and hedgerows. A suite of ecological mitigation measures have been embedded into the design which would retain the existing ecological resources such as water voles, reptiles and bats in-situ. The proposed new habitat would also provide suitable habitat for eels, amphibians, reptiles, invertebrates, mammals and a wide variety of breeding, wintering and foraging birds. The Scheme is not likely to have any significant adverse effects on the adjacent Sizewell Marshes SSSI. Indirect effects associated with potential changes in the flow or quality of controlled waters are unlikely to arise once the habitats within the site have been created, subject (in relation to potential changes in flow) to the ability to use the retained on-site abstraction to provide stream support to maintain flows in Leiston Drain above 11 l/s under drought conditions. This measure is precautionary because daily flow data provided by the Environment Agency for the period 2009 to 2012 indicate that flow from the WWTW is, on average, 18 l/s and the Leiston PWS Licence requires a discharge of up to 570 m 3 /day to Leiston Beck at Lover s Lane when directed to do so by the Environment Agency Permitting and monitoring Operation of the scheme would be carried in accordance with the following permits: Transfer Licence to cover the discharge (transfer) of groundwater from the basins to surface water. Operation of the scheme would be reviewed every 12 years to confirm that management of water levels in the basins does not adversely affect NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 14 of 30

99 flow and levels in the Leiston Beck (to be confirmed in discussions with the EA); Groundwater Abstraction Licence to cover stream support; and Internal Drainage Board Consents to cover routine maintenance of the control structures, the Aldhurst Stream, Leiston Beck and WWTW. Monitoring would also be undertaken and the main elements are: Monitoring of basin water levels (a stage board would be installed in each basin); Inspection of water level control structures to check that eel passage is viable; Measurement of flows in Leiston Beck just upstream of Lover s Lane; Measurement of the volume of any abstraction for stream support. 5 SCREENING AND DETERMINATION OF LIKELY SIGNIFICANT EFFECT 5.1 Introduction Guidance on the determination of likely significant effect has been provided in English Nature s Habitat Regulations Guidance Note 3 (HRGN3 (English Nature. 1999), The Determination of Likely Significant Effect under the Habitats Regulations. As a first step the guidance states that it is necessary to determine whether the proposal is connected with or necessary for the management of the site for its conservation objective. If the proposal is not connected with the management of the site (or sites) the screening should proceed to a fuller consideration of the likely effects. The proposed Aldhurst Farm habitat creation scheme is not necessary for the management of a designated European Site and therefore competent authorities must consider potential effects on European sites. Subsequent sections provide fuller consideration of the likely effects of the scheme and their likely consequences for the conservation objectives of relevant European sites. The following steps in the screening process are presented: Identification of all European sites within spatial extent of likely effects (Section 5.2); Description of the potential effects associated with the scheme, their likely scale, location, likelihood and duration (Section 5.3); Presentation of European site features and conservation objectives (Table 1); Determination of likely significant effects in respect of the site(s) features and conservation objectives (Section 5.3 and Table 1); Consideration of potential in-combination effects with other projects and plans (Section 5.4); and Conclusion on likely significant effect. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 15 of 30

100 5.2 Identification of relevant European sites On the basis of the type of scheme proposed and the nature of the construction activities, it is considered that the effects of the scheme would be localised (see Sections 3-4, above). A maximum 10km search distance to identify European sites that could potentially be affected is therefore considered appropriate and robust for screening purposes. The following European Sites are located within 10km of the site (see Figure 3): Sandlings SPA Minsmere to Walberswick Heaths ad Marshes SAC Minsmere to Walberswick SPA Minsmere to Walberswick Ramsar Outer Thames Estuary SPA Alde-Ore Estuary SPA Alde-Ore and Butley Estuaries SAC Orfordness to Shingle Street SAC Dew s Pond SAC Table 1, below, sets out the designated features of each of the above sites, proximity to Aldhurst Farm and the conservation objectives applicable to each of the sites against which the effects of the scheme are assessed. 5.3 Effects of the Scheme on Designated European Sites Habitat loss and fragmentation The habitat creation works would be confined to the Aldhurst Farm site and would not directly affect any area of European designated site. No direct losses to any designated site would therefore arise. No indirect effects of the Scheme are identified that would result in habitat fragmentation such that designated European interests would be adversely affected. The proposed habitat creation measures would complement similar habitat types that occur within designated sites such as the Minsmere to Walberswick SPA (e.g. reedbed, lowland heathland) and the Sandlings SPA (lowland heathland). While not providing any direct linkage between areas of designated habitat, the scheme would contribute to the overall habitat resource in the wider Suffolk Coast and Heaths area. It would be expected, over time that the habitats at Aldhurst Farm, would potentially support species that are representative of similar habitats that occur within some of the European designated habitats in close proximity and act as a functional link for some interests (e.g. the reedbeds could provide a foraging resource for species such as marsh harrier) Hydrology and Hydrogeology The excavation of the groundwater basins and soil management measures could lead to the generation of sediment laden water which may, through flow into Aldhurst Valley Stream and then Leiston Beck, causing detrimental change in water quality in Leiston NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 16 of 30

101 Drain, which runs along part of the Minsmere to Walberswick SPA / Ramsar (South Minsmere Levels). There is also the potential for accidental releases of pollutants (e.g. oil, diesel) from vehicles during construction works to arise and enter the same watercourses. Adverse changes in water quality linked to an increase in sediment load and / or pollutants could affect the ecological interest of the watercourse, namely its invertebrate fauna and flora, which forms part of the overall designated wetland (Ramsar) interest of the site. The part of Leiston Drain located along the SPA / Ramsar site is approximately 2km downstream of the Aldhurst Farm site. Attenuation of any increased suspended sediment loads would therefore be expected to occur within the watercourse prior to entering the designated site. As stated above (section 4.2), in order to avoid affecting downstream water flows and quality within Leiston Drain good practice measures would be adopted during construction. These measures would be implemented by the contractor to prevent pollution incidents and control surface water run-off and sedimentation. A pollution incident response plan is appended to the Construction Management Strategy. The hydrogeological modelling and detailed water balance calculations carried out for the Scheme indicate that the habitat creation scheme is highly unlikely to affect the water supply to Sizewell Marshes SSSI, which is immediately adjacent to the far southern end of the Minsmere to Walberswick SPA / Ramsar site. Should it be required as a result in changes in groundwater / surface flow conditions during drought conditions, flows to Leiston Drain would be augmented through the retention of the existing Aldhurst Farm groundwater abstraction licence. No adverse effect on flow conditions to the section of the Leiston Drain within the Minsmere to Walberswick SPA / Ramsar site is therefore predicted Air quality The nearest area of designated habitat that could potentially be sensitive to changes in air quality is the lowland heathland habitat of the Sandlings SPA. Small-scale changes in air quality associated with airborne dust and vehicle emissions during the short-term (approximately 8 months) construction works could arise. However, such changes would be localised, temporary and unlikely to alter existing air quality within European designated habitat / sites, to any degree that ecological interests would be adversely affected. No significant effects on lowland heath features are therefore predicted Disturbance Increased noise levels and human presence may cause disturbance to species that are present within the Aldhurst Farm site and its environs during the construction phase for the project. There is no evidence to suggest that the Aldhurst Farm site is used by any species that may form part of the designated species populations of nearby European sites. Direct disturbance and displacement of species that may be using the site as supporting habitat to SPAs / Ramsar sites would therefore not arise. The habitat creation site is located approximately 2km from the nearest part of the Minsmere to Walberswick SPA / Ramsar site and just over 1km from the boundary of the Sandlings SPA. Intermittent increases in noise levels during construction would arise, particularly during earth excavation and soil spreading. Construction noise disturbance effects on birds may manifest up to a distance of 500m, depending on the generated noise levels and species sensitivities (Smit and Visser (1993); IECS (2009), Cutts et al. (2013)). NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 17 of 30

102 However, given the distance of the two nearest designated sites to the works, noise related disturbance effects to breeding SPA bird populations would be highly unlikely to occur. Disturbance effects on wintering populations of SPA birds would not arise as the works would be undertaken between March and October, and therefore outside of the wintering period for these designated populations. Given the distance to the nearest areas of European designated habitat and intervening areas of woodland / plantation and hedgerows that screen the site from view, visual disturbance linked to human activities during the works is not predicted. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 18 of 30

103 Table 1. Summary of potential influence of the Aldhurst Farm Habitat Creation Scheme on European Sites within 10km and conclusions on potential for Likely Significant Effect. Site, applicable conservation objectives and distance from Aldhurst Farm Qualifying Features Potential Influence of Scheme on Designated Features Conclusion on Likely Significant Effect Alde-Ore and Butley Estuaries SAC (5km) Ensure that the integrity of the site is maintained or restored as appropriate, and ensure that the site contributes to achieving the Favourable Conservation Status of its Qualifying Features, by maintaining or restoring: The extent and distribution of qualifying natural habitats and habitats; The structure and function (including typical species) of qualifying natural habitats; and The supporting processes on which qualifying natural habitats rely. Annex I habitats that are a primary reason for selection of this site: 1130 Estuaries Annex I habitats present as a qualifying feature, but not a primary reason for selection of this site: 1140 Mudflats and sandflats not covered by seawater at low tide 1330 Atlantic salt meadows (Glauco-Puccinellietalia maritimae) No direct habitat loss or indirect alteration of habitats (no impact pathway). No hydrological connection with the Aldhurst Farm site (no impact pathway). Air quality effects during construction would be localised to the immediate vicinity of the Aldhurst Farm site and would not affect designated interest features of this site. No impact pathway through which disturbance effects could potentially operate. No Likely Significant Effect Alde-Ore Estuary SPA (5km) Ensure that the integrity of the site is maintained or restored as appropriate, and ensure that the This site qualifies under Article 4.1 of the Directive (79/409/EEC) by supporting populations of European importance of the following species listed on Annex I of the Directive: During the breeding season; No direct habitat loss or indirect alteration of habitats. SPA located outside of any potential zone of disturbance that may arise during the No Likely Significant Effect

104 site contributes to achieving the aims of the Wild Birds Directive, by maintaining or restoring: The extent and distribution of the habitats of the qualifying features; The structure and function of the habitats of the qualifying features; The supporting processes on which the habitats of the qualifying features rely; The population of each of the qualifying features; and The distribution of the qualifying features within the site. Avocet Recurvirostra avosetta, 104 pairs representing at least 17.6% of the breeding population in Great Britain (5 year mean, ) Little Tern Sterna albifrons, 48 pairs representing at least 2.0% of the breeding population in Great Britain (5 count mean, ,1996-8) Marsh Harrier Circus aeruginosus, 3 pairs representing at least 1.9% of the breeding population in Great Britain (5 year mean, ) Sandwich Tern Sterna sandvicensis, 169 pairs representing at least 1.2% of the breeding population in Great Britain (5 year mean ) Over winter; Avocet Recurvirostra avosetta, 766 individuals representing at least 60.3% of the wintering population in Great Britain (5 year peak mean 1991/2-1995/6) This site also qualifies under Article 4.2 of the Directive (79/409/EEC) by supporting populations of European importance of the following migratory species: During the breeding season; Lesser black-backed gull Larus fuscus, 21,700 pairs representing at least 17.5% of the breeding Western Europe/Mediterranean/Western Africa population (Count as at 1998) Over winter; Redshank Tringa totanus, 1,919 individuals representing at least 1.3% of the wintering Eastern Atlantic - wintering population (5 year peak mean 1991/2-1995/6). Assemblage qualification: A seabird assemblage of international importance construction phase. Survey data indicates that the existing habitats at Aldhurst Farm do not support significant numbers of any of the designated species populations. Air quality effects during construction would be localised to the immediate vicinity of the Aldhurst Farm site and would not affect designated interest features of this site.

105 The area qualifies under Article 4.2 of the Directive (79/409/EEC) by regularly supporting at least 20,000 seabirds. During the breeding season, the area regularly supports 59,118 individual seabirds (Count period ongoing) including: Herring Gull Larus argentatus, Black-headed Gull Larus ridibundus, Lesser Black-backed Gull Larus fuscus, Little Tern Sterna albifrons and Sandwich Tern Sterna sandvicensis. Assemblage qualification: A wetland of international importance The area qualifies under Article 4.2 of the Directive (79/409/EEC) by regularly supporting at least 20,000 waterfowl. Over winter, the area regularly supports 24,962 individual waterfowl (5 year peak mean 1991/2-1995/6) including: Black-tailed Godwit Limosa limosa islandica, Dunlin Calidris alpina alpina, Lapwing Vanellus vanellus, Shoveler Anas clypeata, Teal Anas crecca, Wigeon Anas penelope, Shelduck Tadorna tadorna, White-fronted Goose Anser albifrons albifrons, Redshank Tringa totanus and Avocet Recurvirostra avosetta. Alde-Ore Estuary Ramsar (5km) Ramsar criterion 2 The site supports a number of nationally-scarce plant species and British Red Data Book invertebrates. Ramsar criterion 3 The site supports a notable assemblage of breeding and wintering wetland birds. Ramsar criterion 6 Species/populations occurring at levels of international importance. Qualifying Species/populations (as identified at designation): Species regularly supported during the breeding No direct habitat loss or indirect alteration of habitats (no impact pathway). No hydrological connection with the Aldhurst Farm site (no impact pathway). SPA is located outside of any potential zone of disturbance that may arise during the construction phase. Survey data indicates that the existing No Likely Significant Effect

106 season: Lesser Black-backed Gull, Larus fuscus graellsii,: W Europe/Mediterranean/W Africa 5790 apparently occupied nests, representing an average of 3.9% of the breeding population (Seabird 2000 Census) Species with peak counts in winter: Avocet, Recurvirostra avosetta, Europe/Northwest Africa 1187 individuals, representing an average of 1.6% of the population (5 year peak mean 1998/9-2002/3) Common Redshank, Tringa totanus totanus, 2368 individuals, representing an average of 2% of the GB population (5 year peak mean 1998/9-2002/3 habitats at Aldhurst Farm do not support significant numbers of any of the designated species populations. Air quality effects during construction would be localised to the immediate vicinity of the Aldhurst Farm site and would not affect designated interest features of this site. Dew s Ponds SAC (10km) Ensure that the integrity of the site is maintained or restored as appropriate, and ensure that the site contributes to achieving the Favourable Conservation Status of its Qualifying Features, by maintaining or restoring: Annex II species that are a primary reason for selection of this site: 1166 Great crested newt Triturus cristatus No direct habitat loss or indirect alteration of habitats (no impact pathway). No direct/indirect hydrological linkage/impact pathway via effects linked with the Aldhurst Farm Scheme (no impact pathway). No Likely Significant Effect The extent and distribution of qualifying natural habitats and habitats; The structure and function (including typical species) of qualifying natural habitats; and The supporting processes on which qualifying natural habitats rely. No impact pathway through which disturbance effects could potentially operate. Air quality effects during construction would be localised to the immediate vicinity of the Aldhurst Farm site and would not affect designated interest features of this site.

107 The populations of qualifying species. The distribution of qualifying species within the site. Minsmere to Walberswick Heaths and Marshes SAC (2km) Annex I habitats that are a primary reason for selection of this site: No direct habitat loss or indirect alteration of habitats. No Likely Significant Effect Ensure that the integrity of the site is maintained or restored as appropriate, and ensure that the site contributes to achieving the Favourable Conservation Status of its Qualifying Features, by maintaining or restoring: The extent and distribution of qualifying natural habitats and habitats; The structure and function (including typical species) of qualifying natural habitats; and The supporting processes on which qualifying natural habitats rely Annual vegetation of drift lines 4030 European dry heaths Annex I habitats present as a qualifying feature, but not a primary reason for selection of this site: 1220 Perennial vegetation of stony banks Leiston Drain, which runs along the south-western boundary of the site provides a hydrological connection between the SAC and the Aldhurst Farm site. However, the designated habitats are not influenced by flow and water quality conditions within Leiston Drain and would therefore not be influenced by any possible hydrological or water quality changes that may arise (however unlikely) as a result of the Aldhurst Farm habitat creation scheme. No impact pathway through which disturbance effects could potentially operate. Air quality effects during construction would be localised to the immediate vicinity of the Aldhurst Farm site and would not affect designated interest features of this site.

108 Minsmere to Walberswick SPA (2km) Ensure that the integrity of the site is maintained or restored as appropriate, and ensure that the site contributes to achieving the aims of the Wild Birds Directive, by maintaining or restoring: The extent and distribution of the habitats of the qualifying features; The structure and function of the habitats of the qualifying features; The supporting processes on which the habitats of the qualifying features rely; The population of each of the qualifying features; and The distribution of the qualifying features within the site. This site qualifies under Article 4.1 of the Directive (79/409/EEC) by supporting populations of European importance of the following species listed on Annex I of the Directive: During the breeding season; Avocet Recurvirostra avosetta, 91 pairs representing at least 15.4% of the breeding population in Great Britain (RSBP 1996) Bittern Botaurus stellaris, 7 individuals representing at least 35.0% of the breeding population in Great Britain (5 year mean, ) Little Tern Sterna albifrons, 28 pairs representing at least 1.2% of the breeding population in Great Britain (5 year mean, ) Marsh Harrier Circus aeruginosus, 16 pairs representing at least 10.0% of the breeding population in Great Britain (5 year mean, ) Nightjar Caprimulgus europaeus, 24 pairs representing at least 0.7% of the breeding population in Great Britain (Count, as at 1990) Woodlark Lullula arborea, 20 pairs representing at least 1.3% of the breeding population in Great Britain (RSPB, 5 year mean 95-99) Over winter; Avocet Recurvirostra avosetta, 278 individuals representing at least 21.9% of the wintering population in Great Britain (5 year peak mean 1991/2-1995/6) Bittern Botaurus stellaris, 14 individuals representing at least 14.0% of the wintering population in Great Britain (Count as at 1998) Hen Harrier Circus cyaneus, 15 individuals representing at least 2.0% of the wintering No direct habitat loss or indirect alteration of habitats. SPA is located outside of any potential zone of disturbance that may arise during the construction phase. Survey data indicates that the existing habitats at Aldhurst Farm do not support significant numbers of any of the designated species populations. Leiston Drain, which runs along the south-western boundary of the site provides a hydrological connection between the SPA and the Aldhurst Farm site. While the watercourse is unlikely to provide significant supporting habitat to the designated bird populations, flow conditions within it may be locally important in maintaining water levels over part of the Minsmere South Levels. The works and created habitats at Aldhurst Farm would be highly unlikely to directly affect flow rates, volumes and water quality within Leiston Drain. In circumstances that changes in surface water flows / groundwater conditions could result in a reduction in flows to Leiston Drain, flows to Leiston No Likely Significant Effect

109 population in Great Britain (5 year peak mean, 1985/6-1989/90) Drain would be augmented through groundwater abstraction, for which a licence would be retained. No adverse effect on flow conditions to the section of the Leiston Drain within the Minsmere to Walberswick SPA is therefore predicted. Air quality effects during construction would be localised to the immediate vicinity of the Aldhurst Farm site and would not affect designated interest features of this site. Minsmere to Walberswick Ramsar (2km) Ramsar criterion 1 The site contains a mosaic of marine, freshwater, marshland and associated habitats complete with transition areas in between. Contains the largest continuous stand of reedbed in England and Wales and rare transition in grazing marsh ditch plants from brackish to fresh water. Ramsar criterion 2 This site supports nine nationally scarce plants and at least 26 red data book invertebrates. Supports a population of the mollusc narrow-mouthed whorl snail Vertigo angustior (Habitats Directive Annex II; British Red Data Book Endangered), recently discovered on the Blyth estuary river walls. An important assemblage of rare breeding birds associated with marshland and reedbeds including: Bittern Botaurus stellaris, gadwall Anas strepera, teal Anas crecca, shoveler Anas clypeata, marsh harrier Circus aeruginosus, avocet Recurvirostra avosetta No direct habitat loss or indirect alteration of habitats. SPA is located outside of any potential zone of disturbance that may arise during the construction phase. Survey data indicates that the existing habitats at Aldhurst Farm do not support significant numbers of any of the designated species populations. Leiston Drain, which runs along the south-western boundary of the site provides a hydrological connection between the SPA and the Aldhurst Farm site. The watercourse may support some of the invertebrate and plant No Likely Significant Effect

110 and bearded tit Panurus biarmicus species for which the Ramsar site is designated and flow conditions within the watercourse may also be locally important in maintaining water levels over part of the Minsmere South Levels. The works and created habitats at Aldhurst Farm would be highly unlikely to directly affect flow rates, volumes and water quality within Leiston Drain. In circumstances that changes in surface water flows / groundwater conditions could result in a reduction in flows to Leiston Drain, flows would be augmented through groundwater abstraction, for which a licence would be retained. No adverse effect on flow conditions to the section of the Leiston Drain within the Minsmere to Walberswick Ramsar is therefore predicted. Air quality effects during construction would be localised to the immediate vicinity of the Aldhurst Farm site and would not affect designated interest features of this site. Orfordness to Shingle Street SAC (8km) Ensure that the integrity of the site Annex I habitats primary reason for selection: 1150 Coastal lagoons * Priority feature 1210 Annual vegetation of drift lines No direct habitat loss or indirect alteration of habitats (no impact pathway). No Likely Significant Effect

111 is maintained or restored as appropriate, and ensure that the site contributes to achieving the Favourable Conservation Status of its Qualifying Features, by maintaining or restoring: The extent and distribution of qualifying natural habitats and habitats; The structure and function (including typical species) of qualifying natural habitats; and Annex I habitats present as a qualifying feature, but not a primary reason for selection of this site: 1220 Perennial vegetation of stony banks No impact pathway through which disturbance effects could potentially operate. Air quality effects during construction would be localised to the immediate vicinity of the Aldhurst Farm site and would not affect designated interest features of this site. The supporting processes on which qualifying natural habitats rely. Outer Thames Estuary SPA (3km) The conservation objective for the Outer Thames Estuary Special Protection Area is, subject to natural change, maintain or enhance the red-throated diver population (Gavia stellata) and its supporting habitats in favourable condition. The site qualifies under Article 4.1 of the Directive (79/409/EEC) as it is used regularly by 1% or more of the Great Britain population of the following species listed in Annex I in any season: Red-throated diver Gavia stellata, 6,466 individuals representing 38% of the GB population ( /07). No direct habitat loss or indirect alteration of habitats (no impact pathway). SPA is located outside of any potential zone of disturbance that may arise during the construction phase. Air quality effects during construction would be localised to the immediate vicinity of the Aldhurst Farm site and would not affect designated interest features of this site. No Likely Significant Effect Sandlings SPA (1km) This site qualifies under Article 4.1 of the Directive No direct habitat loss or indirect No Likely

112 Ensure that the integrity of the site is maintained or restored as appropriate, and ensure that the site contributes to achieving the aims of the Wild Birds Directive, by maintaining or restoring: The extent and distribution of the habitats of the qualifying features; (79/409/EEC) by supporting populations of European importance of the following species listed on Annex I of the Directive: During the breeding season; Nightjar Caprimulgus europaeus, 109 pairs representing at least 3.2% of the breeding population in Great Britain (Count as at 1992) Woodlark Lullula arborea, 154 pairs representing at least 10.3% of the breeding population in Great Britain (Count as at 1997) alteration of habitats (no impact pathway). SPA is located outside of any potential zone of disturbance that may arise during the construction phase. Survey data indicates that the existing habitats at Aldhurst Farm do not support significant numbers of any of the designated species populations. Significant Effect The structure and function of the habitats of the qualifying features; The supporting processes on which the habitats of the qualifying features rely; Air quality effects during construction would be localised to the immediate vicinity of the Aldhurst Farm site and would not affect designated interest features of this site. The population of each of the qualifying features; and The distribution of the qualifying features within the site.

113 5.4 In-combination effects The screening exercise has determined that there are no impacts of the scheme that would lead to adverse effects on designated sites of European interest that would constitute a likely significant effect. Any identified effects on designated interest features (see Table 1) are considered negligible and it can be concluded that there would not be any potential for significant in-combination effects with other plans of projects to arise. 6 SUMMARY EDF Energy is proposing to convert a 67ha arable farm in Leiston into wetland and terrestrial habitat. The proposed scheme centres on the creation of wetland habitat comprising lowland ditches, reedbed and open water which will occupy approximately 6 ha of low-lying land alongside two existing watercourses. Within 10km of the Aldhurst Farm site there are ten sites designated for their European and international nature conservation importance. The closest of these are the Sandlings SPA (1km) and Minsmere to Walberswick SPA / Ramsar (2km). For the majority of sites there are no impact pathways by which the designated interests would be affected. A number of environmental studies and assessments have been undertaken to inform the construction and design of the scheme and to understand and manage any potential effects. The design of the scheme has developed in consultation with key consultees, including Suffolk Coastal District Council, Suffolk County Council, the Environment Agency, Natural England, Suffolk Wildlife Trust and the RSPB. In particular, studies and assessments have informed the proposed construction methodology and design of the scheme to prevent potential effects on local hydrological and hydrogeological conditions, and downstream surface water flows in Leiston Beck (which runs through Sizewell Marshes and into the southern part of the Minsmere to Walberswick SPA and Ramsar site). During construction, disturbance effects would be localised to the immediate vicinity of the scheme area. Ecological surveys indicate that the site does not provide any significant supporting habitat for SPA designated bird populations and disturbance to designated species populations during construction is therefore highly unlikely to arise. Once created, the new habitats (together with the protected existing habitats) will enhance the floral and faunal biodiversity interests of the site. Assessment of the potential effects of the scheme against the conservation objectives of the relevant European Sites indicates that no significant adverse impacts on the designated interests would arise. It can therefore be concluded that the Aldhurst Farm Habitat Creation Scheme would not give rise to a likely significant effect on any European Site, either alone or in-combination with any other plan or project. NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 29 of 30

114 7 REFERENCES AMEC (2014). Aldhurst Farm: Habitat Creation Scheme. Construction Management Strategy. Cutts N.D. and Hemingway K.L.H (2009). Construction and waterfowl: defining sensitivity, response, impacts and guidance. Report to Humber INCA. Institute of Estuarine and Coastal Studies (IECS), University of Hull. Cutts N.D., Hemingway K.L.H. and Spence J. (2013). Waterbird disturbance mitigation toolkit informing estuarine planning and construction projects. Produced by the Institute of Estuarine and Coastal Studies (IECS), University of Hull for the TIDE Project. Royal HaskoningDHV (2013). Sizewell Marshes SSSI Replacement Habitat Feasibility & Conceptual Design Report. Smit, C and Visser, G.J.M. (1993). Effects of disturbance on shorebirds: a summary of existing knowledge from the Dutch Wadden Sea and Delta area. Wader Study Group Bulletin, 68, NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Page 30 of 30

115 FIGURES NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN

116 FIGURE 1: SITE LOCATION NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN

117 N INTERNAL BUSINESS COLLABORATOR REFERENCE NOT APPLICABLE FOR ALL FIGURES W S E Reproduced from Ordnance Survey map with the permission of Ordnance Survey on behalf of the controller of Her Majesty's Stationery Office Crown Copyright (2014). All Rights reserved. NNB GenCo NOTES: KEY SITE BOUNDARY ALDHURST FARM VALLEY Upper Valley Middle Valley Lower Valley Main watercourse (Aldhurst Valley Stream) Leiston Beck WWTW drain WWTW discharge REVISION DATE DRAWN CHECKED REASONS FOR REVISION/COMMENTS APPROVED DOCUMENT: ALDHURST FARM HABITAT CREATION SCHEME DRAWING TITLE: SITE LOCATION Copyright 2014 EDF Energy plc. No part of this drawing is to be reproduced without prior permission of EDF Energy DRAWING NO: FIGURE DATE: DRAWN: SCALE: REVISION: DEC 2014 S.H 1:5000@A3 SCALE BAR 0 m 300 m DRAWING SECURITY CLASSIFICATION: PROTECTIVE MARKING REQUIRED Shr151.dwg LON-CVD-0001

118 FIGURE 2: EUROPEAN SITES LOCATED WITHIN 10KM OF THE PROPOSED APPLICATION SITE AT ALDHURST FARM NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN

119 Dew's Pond (SAC) ( IN INTERNAL BUSINESS COLLABORATOR REFERENCE NOT APPLICABLE FOR ALL FIGURES Reproduced from Ordnance Survey map with the permission of Ordnance Survey on behalf of the controller of Her Majesty's Stationery Office Crown Copyright (2015). All Rights reserved. NNB GenCo NOTES KEY Site Boundary Ramsar sites Minsmere-Walberswick Heaths and Marshes (SAC, SPA and Ramsar) Special Protection Area (SPA) Special Areas of Conservation (SAC) 10km Radius Outer Thames Estuary (SPA) Sandlings SPA REVISION DATE DRAWN CHECKED REASONS FOR REVISION/COMMENTS APPROVED Alde-Ore and Butley Estuaries (SAC, SPA and Ramsar) DOCUMENT: ALDHURST FARM HABITAT CREATION SCHEME: HRA SCREENING REPORT Sandlings SPA DRAWING TITLE: FIGURE 2: EUROPEAN SITES LOCATED WITHIN 10KM OF THE PROPOSED APPLICATION SITE AT ALDHURST FARM Orfordness-Shingle Street (SAC) DRAWING NO: REVISION: 1.0 DATE: DRAWN: SCALE: DEC 2014 JE SCALE BAR KM Haskoning UK Ltd. Copyright 2015 EDF Energy plc. No part of this drawing is to be reproduced without prior permission of EDF Energy DRAWING SECURITY CLASSIFICATION: PROTECTIVE MARKING REQUIRED

120 THIS PAGE IS LEFT INTENTIONALLY BLANK

121 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version 1.0 APPENDIX C PROOF OF LAND OWNERSHIP NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 13 of 16

122 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version 1.0 NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 14 of 16

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133 NNB Company Document ALDHURST FARM ABSTRACTION LICENSE APPLICATION NNB-209-REP Version 1.0 APPENDIX D PUMP TEST REPORT AND ABSTRACTION VOLUME CALCULATIONS NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED Page 15 of 16

134 NNB Company Document NNB COMPANY DOCUMENT TEMPLATE PROTECTIVE MARKING NNB-301-TEM Version VERSION THIS PAGE IS LEFT INTENTIONALLY BLANK NNB Generation Company Limited Registered in England and Wales. Registered No Registered Office: 40 Grosvenor Place London SW1X 7EN Template No: NNB-301-TEM Template Version: 5.0 Parent procedure: NNB-OSL-PRO UNCONTROLLED WHEN PRINTED PROTECTIVE MARKING Page 16 of 16

135 TABLE 4: EVAPORATIVE DEMAND: REEDBEDS LTA ADDITIONAL EVAPORATIVE DEMAND DUE TO REEDBEDS (Model AE & MODEL PE*Kc) AREA = 5.5ha Model Model Model Model Calc Additonal evapotranspirative demand Available water Additional deficit due to reedbeds Additional deficit due to reedbeds Additional deficit due to reedbeds Additional due to reedbeds Month Rainfall AE PE (MOSES OrigPotEvap) PE (Open Water Kc) Water Demand Water Demand mm/month mm/month mm/month mm/month mm/month mm/month mm/month per ha l/day/ha site l/s site m3/month site m3/d January February March April May June July August September October November December TOTAL DROUGHT PERIOD ADDITIONAL EVAPORATIVE DEMAND DUE TO REEDBEDS (Model AE & MODEL PE*Kc) AREA = 5.5ha Model Model Model Model Calc Additonal evapotranspirative demand Available water Additional deficit due to reedbeds Additional deficit due to reedbeds Additional deficit due to reedbeds Additional due to reedbeds Month Rainfall AE PE (MOSES OrigPotEvap) PE (Open Water Kc) Water Demand Water Demand mm/month mm/month mm/month mm/month mm/month mm/month mm/month per ha l/day/ha site l/s site m3/month site m3/d January February March April May June July August September October November December TOTAL H:\Projects\35242 LON Sizewell Wetland\calcs\WB Calc Update xlsx Tab: Aldhurst Farm

136 1 Amec Foster Wheeler Environment & Infrastructure UK Limited Water Resources Section 32(3) Consent to Investigate a Groundwater Source: Aldhurst Farm Installation of New Abstraction Borehole and Pump Test Analysis 1. Introduction This technical note details the groundwater source investigation works undertaken at Aldhurst Farm under Water Resources (WR) Section 32(3) consent (Environment Agency reference 7/35/03/*G/0049 Aldhurst Farm). The consent allows: The drilling and construction of two new boreholes; and Test pumping and analysis of the new boreholes. 1.1 Scope of Works The objective of the works includes drilling two new boreholes as potential abstraction boreholes to provide flow support to Leiston Beck at the Lover s Lane culvert. Pump testing of the potential abstraction boreholes is required to determine if the wells have sufficient yield to provide flow support and that the effects of abstraction do not result in an adverse effect on the environment. The works were carried out under a WR Section 32(3) consent from the Environment Agency included in Appendix A of this technical note. The WR32(3) consent refers to the existing abstraction licence 7/35/03/*G/0049 located on the Aldhurst Farm site. This licence permits abstraction from a series of 15 well points for spray irrigation between April and September. The licence has an annual quantity of 27,000 m 3 /a and a daily maximum abstraction of 900 m 3 /d. It is proposed that the new abstraction borehole(s) would be licensed under a new application and would replace the existing abstraction licence which would be surrendered. The agreed drilling and testing programme is as follows: Drill abstraction borehole; Undertake air lifting; Undertake step test and determine pumping rate possible for constant rate test; Undertake constant rate test; and Undertake recovery test. 2. Borehole Drilling and Installation The borehole was designed and drilled as per the permitted consent (and subsequently agreed amendments). Borehole 1 NEW (BH1N) was drilled between 24 and 26 February 2015 by Structural Soils with a Dando 3000 rig using a cable percussion drilling method. The location of BH1N is shown in Figure 2.1. The detailed log May 2015 Doc Ref: 32542r072i2

137 2 Amec Foster Wheeler Environment & Infrastructure UK Limited of the geology and borehole installation was provided by Structural Soils, report shown in Appendix B and summarised below: The borehole was drilled to 25 mbgl ( maod) with a 300 mm diameter to 4 mbgl and 254 mm diameter from 4 m 25 mbgl as detailed in the WR32 consent; The borehole was drilled into the Crag, with the geology described as sand from surface to 25 mbgl, with gravel and some silt identified; A water strike was recorded at 4 mbgl (5.62 maod), the rest water level following construction of the borehole was 6.9 mbgl (2.72 maod); A 150 mm diameter slotted screen was installed from 15 to 25 mbgl with a gravel pack installed from 5 to 25 mbgl, a bentonite seal was installed in the top 5 m of the borehole to surface; The well was developed before any testing was undertaken; and A submersible pump and rising main was installed at 20 mbgl. A second borehole, BH2 was drilled to 14.5 mbgl on the 4 and 5 of March 2015, however drilling was terminated due to blowing sands. The borehole was backfilled to surface with bentonite. Accordingly only one borehole (BH1N) was subsequently pump tested. 3. Pump Test Pump Testing was undertaken for two purposes: To determine the yield of borehole BH1N, to confirm whether the borehole can provide sufficient yield for stream support to the Leiston Beck; and To identify any changes in groundwater level recorded at agreed monitoring wells during the pumping test, to investigate the potential effect of the abstraction on environmental receptors. 3.1 Test Monitoring Data loggers were installed in the pumping borehole and four observation boreholes, BH1, BH2, AF1 and AF2, locations shown in Figure 2.1 and grid coordinates listed in Table 3.3 Data loggers were set to record groundwater levels at a one minute interval throughout the testing period, which includes three days of pretest monitoring as specified by the WR32(3) consent. Water levels in the pumping well were also measured manually using a dip level probe at a frequency indicated by the consent WR32(3), as shown in Table 3.1,and twice daily dips undertaken in the observations boreholes. Water level and flow measurements were undertaken in accordance to BS ISO (2003). Monitoring borehole AF1 is installed in the Crag while AF2, BH1 and BH3 are shallow installations in the sands and gravels which overly the Crag. Table 3.1 Monitoring Frequency Time since pumping started Time interval Time interval Duration 0-10 mins 1 mins 10 mins 10-60mins 5 mins 10 mins 60 mins to 8 hours 30 mins 30 mins Over 8 hours Twice Daily Twice Daily Water quality sampling from the abstraction borehole is a requirement of the WR32(3) consent, with a sample to be taken within 24 hours before the end of the pumping test. The consent specifies that analysis for chloride content, electrical conductivity and major ions is undertaken. Five groundwater samples were taken, two May 2015 Doc Ref: 32542r072i2

138 3 Amec Foster Wheeler Environment & Infrastructure UK Limited samples taken on the 13 th March during the step test, one sample on the 16 th and two samples taken on the 17 th of March. Throughout the works, the flow and stage in the Leiston Beck was monitored at gauge G5 (NGR , ). During the step test the abstracted water was discharged to ground, while for the constant rate discharge test the water was discharged to the Leiston Beck. Rainfall data for a nearby rain gauge (at NGR , ) has also been collated, data is discussed in Section Step Drawdown Test A Step Test was undertaken on 13 March 2015 and the details are shown in Table 3.2 below. A step test is a single well test in which the discharge rate is increased in a series of stepped constant rates. The test was used to determine a suitable discharge rate for the constant rate test. The test comprised four steps with the initial step at 2.5 l/s and increasing at increments of 2.5 l/s to a final step of 10 l/s. With the stepped increase in discharge rate during the test, the change in groundwater level for each individual step is between 0.7m and 1.1m, with the overall drawdown for the full test at approximately 3.5m, as shown in Figure 3.1. No significant change in the rate of drawdown with increase in the discharge rate is identified and therefore the drawdown plotted against discharge plots approximately on a straight line, shown in Figure 3.2. At the maximum discharge rate of 10 l/s, the drawdown in the borehole and is maintained at 3.59 m (10.5 mbgl) and the drawdown continues to have the same response as in earlier steps, as shown in Figure 3.2. This indicates that the well has the capacity to provide up to 10 l/s for the constant discharge test without the water level being drawn close to the pump level in the well (20 mbgl). Table 3.2 Step Test Period Pump Rate (litres/sec) Duration Total Drawdown (m) Change in Groundwater level during Step (m) Step hours Step hours Step hours Step hours Post Test Recovery hours Returns to rest level May 2015 Doc Ref: 32542r072i2

139 4 Amec Foster Wheeler Environment & Infrastructure UK Limited Figure 3.1 Aldhurst Farm BH1 Step Test Groundwater Levels Figure 3.2 Aldhurst Farm BH1 Step Test Drawdown vs. Discharge May 2015 Doc Ref: 32542r072i2

140 5 Amec Foster Wheeler Environment & Infrastructure UK Limited 3.3 Constant Rate Discharge & Recovery Test A 3 day constant rate discharge test was undertaken at Aldhurst Farm BH1N from 16 to 19 March 2015 at a rate of 10.4 l/s. Abstracted water was discharged to the Leiston Beck, as detailed in the WR32 consent. The Environment Agency had stipulated in the WR32 that the test should last for 7 days, but with an option to stop after 2 days on mutual agreement with the Environment Agency. Following a review of the groundwater level data from the first two days of the test by both parties, it was agreed with the Environment Agency that the test could be terminated after the third day of pumping. The constant rate test was followed by a recovery test. For the recovery test the pump is turned off and the groundwater allowed to return to a rest level. Once the groundwater level returned to rest level, the recovery test could be terminated, this gave a total time for the recovery test of approximately 22 hours. 3.4 Surface water and rainfall monitoring Throughout the works, the flow and stage in the Leiston Beck was monitored. During the step test the abstracted water was discharged to ground, while for the constant rate discharge test the water was discharged to the Leiston Beck. There was little rainfall during the test with no rainfall recorded between 12 and16 March Rainfall of 0.6mm was recorded on the 17 th and 0.2mm on the 18 th March, with no rainfall recorded on the 19 and 20 of March 2015, as shown in Figure 3.3 (rainfall in green). From the start of the constant rate test on the 16 March, a small increase in the stage and flow in the Leiston Beck can be identified, as shown in Figure 3.3 and Figure 3.4. On the 17 March there is a rainfall event but no obvious corresponding increase is identified in the stage or flow. A small decrease in stage and flow is again seen at the end of the constant discharge test on 19 March No identifiable change in stage in the Leiston Beck is seen during the step test, while due to a suspected error in the data no flow data is available during the step test, shown in Figure 3.4. Figure 3.3 Leiston Beck Stage May 2015 Doc Ref: 32542r072i2

141 6 Amec Foster Wheeler Environment & Infrastructure UK Limited Figure 3.4 Leiston Beck flow 3.5 Constant Rate Discharge Test Results & Analysis Figure 3.5 Groundwater level during the constant rate test May 2015 Doc Ref: 32542r072i2

142 7 Amec Foster Wheeler Environment & Infrastructure UK Limited The groundwater levels during the constant discharge pumping test were recorded in the abstraction well by a datalogger and were also manually dipped at the interval indicated by the WR32. The groundwater level for the test is shown in Figure 3.5. The initial rapid change in groundwater level in the well predominantly represents well losses with little attributed to aquifer drawdown. As the pumping continues the well losses have less effect on the water levels and groundwater level change is representative of the change in level in the aquifer. Therefore to investigate the aquifer properties for the Crag, the data from later in the test is analysed. The total drawdown at the end of the test was 3.9 m. Figure 3.6 Theis analysis of constant rate test Hydrosolv s Aqtesolve Software Version 4.5 pump test analysis software has been used to undertake the analysis for the constant discharge test. Figure 3.6 presents the Theis Analysis for an unconfined aquifer on the groundwater data from the abstraction well. With the well losses and turbulence associated with the data for single well test, the data does not present a good fit with the Theis curve but by fitting the curve to the late time data, the analysis gives a good approximation of the aquifer properties, shown in Figure 3.6, with a transmissivity of 879 m 2 /day. The data has also been analysed using Copper-Jacob methodology with log of time plotted against drawdown in the well. As with the Theis analysis, the late time data is fitted to the straight line analysis and calculates similar high transmissivity values for the aquifer as those calculated by the Theis analysis. The Cooper-Jacobs Analysis was also completed within the Aqtesolve Software and is shown in Figure 3.7. May 2015 Doc Ref: 32542r072i2

143 8 Amec Foster Wheeler Environment & Infrastructure UK Limited Figure 3.7 Cooper- Jacobs analysis of constant rate test The groundwater level data recorded at the monitoring borehole locations at one minute intervals are shown in Figure 3.8. The distances for the abstraction borehole and rest water level have been recorded in Table 3.3. There was little change in groundwater level identified at BH1, while BH3, AF1 and AF2 show a decrease in groundwater level during the constant head test of up to 5 cm, as detailed in Table 3.3, and with an equivalent rise in levels during the recovery test. Table 3.3 Monitoring borehole location and groundwater level Borehole ID Eastings Northings Distance from abstraction BH1N (m) Rest groundwater level (mbgl) Maximum Drawdown during pump test (m) BH1NEW BH BH AF AF May 2015 Doc Ref: 32542r072i2

144 9 Amec Foster Wheeler Environment & Infrastructure UK Limited Figure 3.8 Groundwater level during the constant rate and recovery test 3.6 Recovery Test Results & Analysis The recovery test was undertaken for 22 hours following the constant rate test. Similar to the constant rate pumping test, the early time data is affected by well losses with the late time data representing the change in water level within the aquifer. Cooper Jacobs Recovery analysis was used to give an indication of the aquifer properties with the transmissivity (T) calculated by equation 1, shown below. The pump test analysis plots the drawdown against the log of the time with the slope between a log period indicating T = Q/ 4 π δ(s - s ) (Equation 1) For one log period within the late time data, the change in drawdown (δs) is m giving T of 754 m 2 /day. This is consistent with the transmissivity values which were calculated for the constant discharge test. May 2015 Doc Ref: 32542r072i2

145 10 Amec Foster Wheeler Environment & Infrastructure UK Limited Figure 3.9 Cooper-Jacob Analysis of recovery test data 4. Groundwater level response at the SSSI The SSSI boundary is located approximately 500 m from the new abstraction borehole BH1N, however, the sensitive groundwater dependent ecology is located a further 250 m to the northeast, approximately 750 m from the abstraction borehole BH1N. From the pumping test results calculated in section 3 above, the potential change to the groundwater level below the SSSI at 750m from the abstraction has been calculated using the Cooper-Jacob equation for an unconfined aquifer with time variance in Table 4.1. A range of pumping rates and durations have been investigated to determine the range of groundwater level change which might be expected. The Cooper-Jacobs equation calculates a change of < 0.01m in groundwater level for abstraction rate of 2 l/sec for up to 100 days duration at 750 m from the abstraction. For the licensed pump rate of 10.4 l/s, a change of 0.1 m is seen for a 30 days duration. No drawdown is seen 750 m from the abstraction for the licensed abstraction rate in the first 10 days of pumping. Table 4.1 Potential change in groundwater levels at the SSSI with pumping Pumping Rate (l/sec) Duration (days) Transmissivity (m 2 /day) Storage Potential change in groundwater level at SSSI (m) <0.01 May 2015 Doc Ref: 32542r072i2

146 11 Amec Foster Wheeler Environment & Infrastructure UK Limited 5. Water Quality Analysis Five groundwater samples were taken and the laboratory results are shown in Table 5.1, and laboratory reports are provided in Appendix C. No significant change in water quality was identified from the step test on the 13 March 2015 to the first day of the pumping test on the 16 March 2015, with only minor changes in water quality reported. This indicated that there were no sources of sources of potentially polluting substances close to the abstraction and no contamination was mobilised during the pumping test. Table 5.1 Step Test BH1N-S1 BH1N-S2 BH1N-S2 BH1N-S3 BH1N-S4 Parameter LOD Units 13-Mar Mar Mar Mar Mar-15 Alkalinity as CaCO3 20 mg/l Ammonia as NH mg/l <0.05 <0.05 <0.05 Calcium 0.5 mg/l Chloride 1 mg/l Electrical Conductivity 1 µs/cm Fluoride 0.05 mg/l Fe (Total) mg/l Magnesium 0.1 mg/l Mn (total) mg/l Nitrate 0.5 mg/l ph Phosphate 0.5 mg/l <0.5 <0.5 <0.5 Potassium 0.05 mg/l Sodium 0.05 mg/l Suspended Solids 10 mg/l <10 <10 <10 May 2015 Doc Ref: 32542r072i2

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148 13 Amec Foster Wheeler Environment & Infrastructure UK Limited Third party disclaimer Any disclosure of this report to a third party is subject to this disclaimer. The report was prepared by Amec Foster Wheeler at the instruction of, and for use by, our client named on the front of the report. It does not in any way constitute advice to any third party who is able to access it by any means. Amec Foster Wheeler excludes to the fullest extent lawfully permitted all liability whatsoever for any loss or damage howsoever arising from reliance on the contents of this report. We do not however exclude our liability (if any) for personal injury or death resulting from our negligence, for fraud or any other matter in relation to which we cannot legally exclude liability. Management systems This document has been produced by Amec Foster Wheeler Environment & Infrastructure UK Limited in full compliance with the management systems, which have been certified to ISO 9001, ISO and OHSAS by LRQA. May 2015 Doc Ref: 32542r072i2

149 Key Aldhurst Monitoring borehole file: G:\MODEL\PROJECTS\HM-250\35242\ArcGIS\Figures\35242-Shr168.mxd Based upon the Ordnance Survey Map with the permission of the Controller of Her Majesty's Stationery Office. Crown AF1 BH m Scale at A3: 1:4,500 Aldhurst Farm Installation of New Abstraction Borehole and Pumping Test Analysis Figure 2.1 Borehole location plan May Shr168.mxd barkr

150 Amec Foster Wheeler Environment & Infrastructure UK Limited Appendix A WR32(3) Groundwater Investigation Consent Aldhurst Farm May 2015 Doc Ref: 32542r072i2

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167 Amec Foster Wheeler Environment & Infrastructure UK Limited Appendix B Borehole 1 Geological Log (from Factual Report on Ground Investigation, Structural Soils, April 2015) May 2015 Doc Ref: 32542r072i2

168 Contract: Contract Ref: Depth STRUCTURAL SOILS Samples and In-situ Tests No Type D B Results Water Backfill & Instrumentation Client: Description of Strata FINAL BOREHOLE LOG Borehole: Sizewell - Aldhurst Farm NNB Generation Comany Ltd BH1 Start: Ground Level: National Grid Co-ordinate: Sheet: End: E: N: of 3 Brown slightly silty slightly gravelly fine to medium SAND. Gravel is angular to rounded fine to coarse of flint and quartzite. Orange slightly silty slightly gravelly medium SAND. Gravel is angular to subrounded fine to medium occassionally coarse of flint and quartzite. Depth (Thick ness) 0.30 Material Graphic Legend GINT_LIBRARY_V8_05.GLB LibVersion: v8_05 - Lib0004 PrjVersion: v8_05 - Core+Logs 0003 Log CABLE PERCUSSION LOG SIZEWELL - ALDHURST FARM.GPJ - v8_05 19/05/15-15:06 CH. Structural Soils Ltd, Branch Office - Castleford: The Potteries, Pottery Street, Castleford, West Yorkshire, WF10 1NJ. Tel: , Fax: , Web: ask@soils.co.uk Date 23/02/15 24/02/15 25/02/15 Method Used: Boring Progress and Water Observations Borehole Time Diameter (mm) 22: :07 D B D B D B D B D B D B D B D B Borehole Depth Casing Depth below 2.50m sand is medium to coarse. Orange slightly gravelly silty medium SAND. Gravel is rounded to subrounded fine to medium nodules of ferras sandstone and mudstone.... below 6.50m, occasional thin laminations/lenses of soft grey clay 2mm-4mm. Orange slightly silty slightly gravelly medium to coarse grained SAND. Gravel is subangular to subrounded medium to coarse of sandstone.... below 8.50m, occasional sandstone fragments Water Depth Dry 4.00 Dry Plant Cable percussion Used: Dando 4000 Chiselling / Slow Progress From To Drilled By: Duration (hh:mm) 02:00 (3.20) 3.50 (4.00) 7.50 General Remarks 1. Hand dug inspection pit to 1.20m. 2. Groundwater encountered at 4.00m. 3. Blowing sands from 21.40m m. 4. Borehole installed with a 152mm diameter well upon completion. 5. Installed headworks are 10.50m AOD (0.88m above ground level) All dimensions in metres Scale: 1:50 Logged Checked By: By:

169 Contract: Contract Ref: Depth STRUCTURAL SOILS Samples and In-situ Tests No Type D B Results Water Backfill & Instrumentation Client: Description of Strata FINAL BOREHOLE LOG Borehole: Sizewell - Aldhurst Farm NNB Generation Comany Ltd BH1 Start: Ground Level: National Grid Co-ordinate: Sheet: End: E: N: of 3 Orange slightly silty slightly gravelly medium to coarse grained SAND. Gravel is subangular to subrounded medium to coarse of sandstone. (stratum copied from 7.50m from previous sheet) Depth (Thick ness) (5.00) Material Graphic Legend GINT_LIBRARY_V8_05.GLB LibVersion: v8_05 - Lib0004 PrjVersion: v8_05 - Core+Logs 0003 Log CABLE PERCUSSION LOG SIZEWELL - ALDHURST FARM.GPJ - v8_05 19/05/15-15:06 CH. Structural Soils Ltd, Branch Office - Castleford: The Potteries, Pottery Street, Castleford, West Yorkshire, WF10 1NJ. Tel: , Fax: , Web: ask@soils.co.uk Date Method Used: D B D B D B D B D B D B D B D B Boring Progress and Water Observations Borehole Casing Borehole Time Diameter Depth Depth (mm) Orange slightly silty gravelly medium to coarse SAND. angular fine to mediumof shell fragments m, tabular coarse gravel size fragments of mudstone.... between 14.50m-17.50m, sand is coarse. Water Depth Plant Cable percussion Used: Dando 4000 Chiselling / Slow Progress From To Drilled By: Duration (hh:mm) Gravel is (9.00) General Remarks All dimensions in metres Scale: 1:50 Logged Checked By: By:

170 Contract: Contract Ref: Depth STRUCTURAL SOILS Samples and In-situ Tests No Type D B Results Water Backfill & Instrumentation Client: Description of Strata FINAL BOREHOLE LOG Borehole: Sizewell - Aldhurst Farm NNB Generation Comany Ltd BH1 Start: Ground Level: National Grid Co-ordinate: Sheet: End: E: N: of 3 Orange slightly silty gravelly medium to coarse SAND. Gravel is angular fine to mediumof shell fragments. (stratum copied from 12.50m from previous sheet) m, occasional tabular medium to coarse gravel size fragments of sandstone. Depth (Thick ness) Material Graphic Legend GINT_LIBRARY_V8_05.GLB LibVersion: v8_05 - Lib0004 PrjVersion: v8_05 - Core+Logs 0003 Log CABLE PERCUSSION LOG SIZEWELL - ALDHURST FARM.GPJ - v8_05 19/05/15-15:06 CH. Structural Soils Ltd, Branch Office - Castleford: The Potteries, Pottery Street, Castleford, West Yorkshire, WF10 1NJ. Tel: , Fax: , Web: ask@soils.co.uk Date Method Used: D B D B D B D B D B D B Boring Progress and Water Observations Borehole Casing Borehole Time Diameter Depth Depth (mm)... below 19.50m, sand is medium.... below 20.50m, sand is fine to medium and slightly gravelly. Orange slightly silty gravelly coarse SAND. Gravel is angular fine to medium of shell fragments. Borehole terminated at 25.00m depth. Water Depth Plant Cable percussion Used: Dando 4000 Chiselling / Slow Progress From To Drilled By: Duration (hh:mm) (3.50) General Remarks All dimensions in metres Scale: 1:50 Logged Checked By: By:

171 Amec Foster Wheeler Environment & Infrastructure UK Limited Appendix C Water Quality Analysis May 2015 Doc Ref: 32542r072i2

172 Scientific Analysis Laboratories is a limited company registered in England and Wales (No ) whose address is at Hadfield House, Hadfield Street, Manchester M16 9FE Scientific Analysis Laboratories Ltd Certificate of Analysis 3 Crittall Drive Springwood Industrial Estate Braintree Essex CM7 2RT Tel : Fax : Report Number: Date of Report: 20-Mar-2015 Customer: Structural Soils Ltd 18 Frogmore Road Hemel Hempstead Hertfordshire HP3 9RT Customer Contact: Ms S Haynes Customer Job Reference: Customer Site Reference: Aldhurst Date Job Received at SAL: 18-Mar-2015 Date Analysis Started: 18-Mar-2015 Date Analysis Completed: 20-Mar-2015 The results reported relate to samples received in the laboratory Opinions and interpretations expressed herein are outside the scope of UKAS accreditation This report should not be reproduced except in full without the written approval of the laboratory Tests covered by this certificate were conducted in accordance with SAL SOPs All results have been reviewed in accordance with QP Report checked and authorised by : Project Manager Issued by : Project Manager This document has been printed from a digitally signed master copy Page 1 of

173 SAL Reference: Project Site: Aldhurst Customer Reference: Water Water suite Analysed as Water Determinand Method SAL Reference Customer Sample Reference BH1-S2 BH1-S3 BH1-S4 Test Sample LOD Date Sampled 16-MAR MAR MAR-2015 Alkalinity expressed as CaCO3 T22 AR 20 mg/l Ammonia expressed as NH3 T686 F 0.05 mg/l <0.05 <0.05 <0.05 Calcium T6 AR 0.5 mg/l Chloride T686 F 1 mg/l Electrical Conductivity T7 AR 1 µs/cm Fluoride T686 F 0.05 mg/l Fe (Total) T301 AR mg/l Magnesium T6 AR 0.1 mg/l Mn (Total) T301 AR mg/l Nitrate T686 F 0.5 mg/l ph T7 AR Phosphate T686 F 0.5 mg/l <0.5 <0.5 <0.5 Potassium T6 AR 0.05 mg/l Sodium T6 AR 0.05 mg/l Suspended Solids (Total) T2 AR 10 mg/l <10 <10 <10 Units Index to symbols used in Value F AR U N Description Filtered As Received Analysis is UKAS accredited Analysis is not UKAS accredited Method Index Value T6 T2 T301 T686 T22 T7 Description ICP/OES Grav ICP/MS (Total) Discrete Analyser Titration Probe Determinand Method Test Sample Accreditation Summary Alkalinity expressed as CaCO3 T22 AR 20 mg/l U Ammonia expressed as NH3 T686 F 0.05 mg/l U Calcium T6 AR 0.5 mg/l U Chloride T686 F 1 mg/l U Electrical Conductivity T7 AR 1 µs/cm U Fluoride T686 F 0.05 mg/l U Fe (Total) T301 AR mg/l U Magnesium T6 AR 0.1 mg/l U Mn (Total) T301 AR mg/l U Nitrate T686 F 0.5 mg/l U ph T7 AR U Phosphate T686 F 0.5 mg/l U Potassium T6 AR 0.05 mg/l U Sodium T6 AR 0.05 mg/l U Suspended Solids (Total) T2 AR 10 mg/l N LOD Units Symbol SAL References Produced by Scientific Analysis Laboratories Ltd, 3 Crittall Drive, Springwood Industrial Estate, Braintree, Essex, CM7 2RT Page 2 of 2 This document has been printed from a digitally signed master copy

174 Scientific Analysis Laboratories is a limited company registered in England and Wales (No ) whose address is at Hadfield House, Hadfield Street, Manchester M16 9FE Scientific Analysis Laboratories Ltd Certificate of Analysis 3 Crittall Drive Springwood Industrial Estate Braintree Essex CM7 2RT Tel : Fax : Report Number: Date of Report: 13-Mar-2015 Customer: Structural Soils Ltd 18 Frogmore Road Hemel Hempstead Hertfordshire HP3 9RT Customer Contact: Customer Job Reference: Customer Site Reference: Aldhurst Date Job Received at SAL: 13-Mar-2015 Date Analysis Started: 13-Mar-2015 Date Analysis Completed: 13-Mar-2015 The results reported relate to samples received in the laboratory Opinions and interpretations expressed herein are outside the scope of UKAS accreditation This report should not be reproduced except in full without the written approval of the laboratory Tests covered by this certificate were conducted in accordance with SAL SOPs All results have been reviewed in accordance with QP Report checked and authorised by : Customer Service Manager Issued by : This document has been printed from a digitally signed master copy Customer Service Manager Page 1 of