Wylfa Newydd Nuclear Power Station

The views expressed in this page do not represent those of the Planning Inspectorate. This page consists of content submitted to the Planning Inspectorate by the public and other interested parties, giving their views of this proposal.

Wylfa Newydd Nuclear Power Station

Received 10 August 2018
From Natural Resources Wales






1.1. NRW have identified key concerns relating to the following areas. We provide further details and clarification below:

• Code of Construction Practice
• Waste

• Flood Risk
• Water Framework Directive
O The Skerries Coastal Water Body
O Ynys Môn Secondary Groundwater Body
O Cemlyn Lagoon Water Body
O Article 4(7) Information
O Cemaes Bathing Water
• Habitats Regulations Assessment
O Morwenoliaid Ynys Môn / Anglesey Terns Special Protection Area (SPA)
O Dee Estuary SPA
O Bae Cemlyn / Cemlyn Bay Special Area of Conservation (SAC)
• Site of Special Scientific Interest (SSSI)
o Tre’r Gôf SSSI
o Tre’r Gôf SSSI Compensation
o Cae Gwyn SSSI
• European and Nationally Protected Species
• Marine Environment
• Protected Landscapes

• Flood Risk
• Foul Drainage

• Flood Risk
• European and Nationally Protected Species

1.2. Our comments are made without prejudice to any further comments we may wish to make in relation to this application and examination whether in relation to the Environmental Statement (ES), provisions of the draft Development Consent Order (‘DCO’) and its Requirements, Statements of Common Ground (SoCG) or other evidence and documents provided by Horizon Nuclear Power (‘the Applicant’), the Examining Body or other interested parties. The following paragraphs comprise our relevant representation as a Statutory Party under the Planning Act 2008 and Infrastructure Planning (Interested Parties) Regulations 2015 and as an ‘interested party’ under s102(1) of the Planning Act 2008.

1.3. We shall continue to provide advice to the applicant through correspondence and meetings with the aim of reaching as many positions of agreement and common ground as possible prior to the examination of the proposals. Our relevant representation is based solely on the information provided within the application documents. Any changes in our position will be reflected in our full written representation and SoCG.

1.4. In addition to being an interested party under the Planning Act 2008, NRW exercises functions under distinct legislation including (but not limited to) the Environmental Permitting (England and Wales) Regulations (EPR) 2016 (as amended), Water Resources Act 1991 and Marine and Coastal Access Act (MACAA) 2009. NRW has received applications for a Construction Environmental Permit, Operational Environmental Permit and Combustion Installations Permit under the EPR Regulations 2016 (as amended), and a Marine Licence application under the MACAA 2009. For the purpose of clarity, comments from NRW Marine Licensing are titled as such and are produced in Annex A; all other comments pertain to NRW’s advisory role.

1.5. NRW provide the comments below (structured according to the reference used in the Environmental Statement) on Volumes 6 C – H which cover Project Wide Effects (Vol 6C), Main Site (Vol 6D) and Associated Developments (Vol E – H). We provide a comment on the Code of Construction Practices for the Wylfa Newydd Project in section 2 below, and on NRW’s general purpose in section 8. In Annex A, we also provide a comment with respect to the draft DCO Requirements in relation to activities which are also licensable under the MACAA 2009.


2.1. The Wylfa Newydd CoCP, together with location-specific sub-CoCPs, are intended to set out how construction activities will be managed and controlled in order to deliver the mitigation commitments arising from the project. There is insufficient detail in the submitted Sub-CoCPs to demonstrate that construction activities will be managed appropriately. NRW advise that if the DCO is made, that detailed Sub-CoCPs will need to be agreed with the consenting authority(ies) as well as NRW as a statutory consultee. We would expect this to be secured as a DCO Requirement.


3.1. Waste

3.1.1. There is insufficient detail in ES chapter C6 to demonstrate how construction generated waste will be managed. The assessment of available waste management capacity will need to be updated prior to and throughout the construction phase, to ensure that appropriate decisions on waste management routes are taken for the duration of the scheme. The principles of the Waste Hierarchy will need to be applied at all times. NRW advises that if the DCO is made, that a detailed Site Waste Management Plans will need to be agreed with the consenting authority(ies) as well as NRW as a statutory consultee. We would expect this to be secured as a DCO Requirement.


4.1. Flood Risk

4.1.1. NRW has significant concerns that, through modifying and increasing catchment areas at the Wylfa Newydd main site, the project may cause unacceptable flood risk to third party property and/or land.

4.1.2. The Flood Consequence Assessment (FCA) identifies that through modifying the catchment area of Nant Cemaes, there is predicted to be an increased flood risk to residential and commercial properties upstream of Cemaes village. The increased flood depth for the 1 in 100 event (1% Annual Exceedance Probability (AEP)) is predicted to be 40mm. The proposals will also increase the catchment area for the Nant Cemlyn and Afon Cafnan watercourses. The FCA predicts the proposals will result in an increase in flood depth for the 1 in 100 event (1% AEP) for the Afon Cafnan of between 60mm and 140mm. The FCA predicts an increase of 20mm in flood depth for the 1 in 100 event (1% AEP) for the Nant Cemlyn stream. Technical Advice Note (TAN) 15, which provides technical guidance that supplements the policy set out in Planning Policy Wales in relation to development and flooding, states that there should be no increased flood risk elsewhere.

4.1.3. In view of the increased flood risks highlighted in 4.1.2, the FCA states that “the outline landform and drainage scheme would be revised at detailed design stage so as not to exacerbate any existing flood risk”. NRW is concerned that no mitigation is presented as part of the DCO application to demonstrate that measures can be delivered to mitigate the increased flood risk. NRW advises that details of mitigation measures should be presented to the Examining Authority to demonstrate that increased flood risk can be managed and that the proposals are compliant with TAN15.

4.2. Water Framework Directive (WFD)

- The Skerries Coastal Water Body

4.2.1. NRW agrees with the conclusion of the WFD Compliance Assessment (WFD CA) that the hydromorphological conditions quality element may deteriorate from high to good status. NRW agrees that, for this quality element, there will be a need for a derogation under Article 4(7) of the WFD.

4.2.2. NRW advises that further information is required to demonstrate that benthic invertebrates would not be at risk of deterioration as a result of the Wylfa Newydd project.

- Ynys Môn Secondary Groundwater body

4.2.3. NRW agrees with the conclusion of the WFD CA that there is potential for the Wylfa Newydd Project (including dewatering effects) to cause a deterioration in the Ynys Môn Secondary groundwater body due to saline intrusion. This effect is relevant to both quantitative and chemical tests for saline intrusion.

4.2.4. In relation to the Groundwater Dependent Terrestrial Ecosystem (GWDTE) quality element, NRW agrees that the Wylfa Newydd Project could cause deterioration in the status of the Ynys Môn Secondary groundwater body with respect to the effects on Tre’r G?f Site of Special Scientific Interest (SSSI) GWDTE.

4.2.5. NRW agrees with the conclusion of the WFD CA that, for the quality elements highlighted in 4.2.3 and 4.2.4 in the Ynys M?n Secondary groundwater body, there will be a need for derogation under Article 4(7) of the WFD.

- Cemlyn Lagoon Coastal Water Body

4.2.6. NRW advises that further information is required to demonstrate that Cemlyn Lagoon will not be affected by impacts on water quality due to surface water run-off from Mound E. Further information is also required to demonstrate that changes in coastal processes due to the presence of the marine structures will not affect the shingle ridge, which supports the functioning of Cemlyn Lagoon. NRW is therefore, unable to agree with the conclusion that "the Wylfa Newydd Project would neither cause deterioration in the status of the Cemlyn Lagoon water body, nor compromise the ongoing achievement of its objectives". Please see section 4.3.8 – 4.3.11 for NRW’s advice in relation to Cemlyn Bay SAC.

- Article 4(7) Supporting Information

4.2.7. NRW advises that further evidence is needed to support the information provided and to justify the conclusions reached in the document regarding mitigation measures, environmental impacts and alternatives considered.

4.2.8. The Article 4(7) report (Ref no. 8.27) identifies water bodies and elements that the applicant considers will require derogation. It is important that the scope of the report is reviewed following the completion of the consenting authority(ies) WFD compliance assessment and any potential updates (such as further water bodies and/or elements to be included in the scope of Article 4(7)) are provided.

- Cemaes Bathing Water

4.2.9. NRW does not agree with the conclusion that “there are no effects predicted on the bathing water at Cemaes, and that the Wylfa Newydd Project is considered to be compliant with the Bathing Water Directive”.

4.2.10. NRW has previously advised the applicant that discharges of elevated suspended solids and sewage discharges into the marine environment has the potential to affect Cemaes Bathing Water. NRW does not consider that the sewage modelling has been conducted appropriately and that further modelling, including meteorological conditions, will need to be conducted. NRW advises that a Bathing Water Compliance Assessment be provided to examine how both the construction sewage discharge and site campus discharges (via the D?r Cymru Welsh Water (DCWW) sewage works) impact the Bathing Water. NRW would expect the applicant to work closely with DCWW to model both discharges, to ensure all discharges are included appropriately. NRW also advises that clarification is required regarding the suspended sediment modelling undertaken.

4.3. Habitats Regulations Assessment (HRA)

- Morwenoliaid Ynys Môn / Anglesey Terns SPA

4.3.1. NRW considers that the evidence and mitigation presented in the Shadow HRA does not demonstrate that noise and vibration associated with the construction phase will not have adverse effects on the sandwich, arctic and common tern populations at the Cemlyn colony. NRW considers that adverse effects on the SPA (relating to sensitivity of sandwich, arctic and common terns to construction noise) cannot be ruled out.

4.3.2. NRW advises that the increase in noise and visual stimuli on land and sea, from the cumulative building activity, may potentially lead to abandonment and/or a decrease in productivity of the Sandwich tern feature of the SPA and thus an adverse effect on the Sandwich tern conservation objectives for productivity and population. NRW also advises that the impacts from increased noise and visual stimuli may potentially lead to the abandonment of the colony by the Arctic and common tern features of Anglesey SPA which would be an adverse effect on the conservation objective for range.

4.3.3. With regards to fish (as prey items of terns), there is no consideration of the effect of the creation of a sheltered bay as a result of the breakwater and thus the possible increased use of the area by some fish species – this could potentially result in increased impingement rates for some species. There is also the risk of large amounts of shoaling fish, such as sandeels, sprats, and herring, being herded into the area behind the breakwater by predators. In certain weather conditions and at certain times of the year, this could increase the impingement of these species which are a food source for terns.

4.3.4. Further information is also required to demonstrate that changes in coastal processes due to the presence of the marine structures will not affect the shingle ridge, which supports the functioning of Cemlyn Lagoon (including the tern breeding islands within the lagoon).

4.3.5. In view of the above comments, NRW is unable to rule out an adverse effect on the site integrity of the Morwenoliaid Ynys Môn / Anglesey Terns SPA.

4.3.6. NRW, as the Appropriate Nature Conservation Body, advise that it cannot be ascertained that the Wylfa Newydd project will not adversely affect the integrity of the Anglesey Terns SPA and that the project would need to be modified accordingly so that any adverse effects can be ruled out. If not, for consent to be granted the provisions of Regulation 64 of the Conservation of Habitats and Species Regulations 2017 must be satisfied - that there are no alternative solutions and that the project must be carried out for imperative reasons of overriding public interest. If the competent authority is satisfied that there are no alternative solutions and that the project must be carried out for imperative reasons of overriding public interest, then compensatory measures would need to be secured.

- Dee Estuary SPA

4.3.7. We are aware that some sandwich terns that breed at Cemlyn also form part of the Passage Sandwich Tern feature of the Dee Estuary SPA. Abandonment of the Cemlyn population as a result of Wylfa Newydd project could therefore impact the conservation objective for the Dee Estuary SPA which is to maintain the population of passage Sandwich terns at the 5-year peak mean population of 957 individuals from 1995 – 1999. NRW therefore advises that an adverse effect on site integrity cannot be ruled out.

- Bae Cemlyn / Cemlyn Bay SAC

4.3.8. Cemlyn Bay SAC consists of two features, the coastal lagoon and the perennial vegetation of stony banks (i.e. the Esgair Gemlyn shingle ridge).

4.3.9. NRW advises that Esgair Gemlyn, which is critical to the functioning of the lagoon and in supporting the shingle ridge vegetation, may be affected by the marine structures. Further information is required with respect to coastal processes modelling to understand whether the Wylfa Newydd project may cause an adverse effect on Esgair Gemlyn. There are still outstanding issues as follows:
a) No coupled wave-bed shear stress modelling of a North West 99%ile storm event to show morphological impacts on Esgair Gemlyn;
b) Lack of sediment data in Cemlyn Bay which then limits assessment of impact;
c) There are protective structures (rock foundation overlain by concrete mats) surrounding the waste water outfall pipe (adjacent the western breakwater) which will be in place for the length of the construction phase. The impact of this structure has not been modelled and assessed.
It is therefore not possible to assess whether focussed energy from the marine structures may cause deposit of fines, reworking of the gravel or a breach at Esgair Gemlyn. The above information is required in order to inform the competent authority’s HRA.

4.3.10. As highlighted in comment 4.2.6 above, further information is required to demonstrate that Cemlyn Lagoon will not be affected by impacts on water quality due to surface water run-off from Mound E. We note that the project design has been amended and that no construction water discharge is now proposed to be discharged into Nant Cemlyn via discharge location E1 until vegetation has been re-established on the western slope of Mound E. Further clarity is required in relation to the mitigation measures detailed in 7.4.5 of the Shadow HRA and in relation to the drainage proposed on and around Mound E. It appears to NRW that pumping capacity is limited and that in extreme events some runoff will enter Nant Cemlyn; clarification from the applicant is required on the level and frequency of such occurrence.

4.3.11. In view of the comments in 4.3.9 and 4.3.10 above, NRW considers at this point that it is not possible to rule out adverse effect on site integrity of the Cemlyn Bay SAC.

4.4. Sites of Special Scientific Interest (SSSIs)

- Tre’r Gôf SSSI

4.4.1. Based on the ES and supporting ES Appendices, NRW advises that the proposed works are likely to significantly affect the functioning of the SSSI and likely to damage the SSSI features. The proposed mounding and drainage proposals, dewatering of the deep excavations as well as locating the Site Campus immediately adjacent to the SSSI pose a number of risks to the SSSI. NRW note that fen creation is proposed as SSSI compensation due to the likely loss of the SSSI (see our advice below on SSSI compensation). However, NRW advised the applicant in our Section 42 responses that all reasonable alternatives and mitigation should be considered to reduce and avoid effects on the SSSI. NRW consider that there is inadequate consideration of direct mitigation measures in the ES.

4.4.2. NRW does not agree with the conceptual hydrogeological modelling undertaken and used to assess impacts on Tre’r Gôf SSSI. It is based on an unsupported assumption that shallow and deep groundwater behave independently. The evidence does not support this. NRW consider that the dewatering has the potential to cause significant damage to the SSSI.

4.4.3. The embedded mitigation refers to the use of an underlying “blanket” (a gravel layer under the mounds) for which its success is uncertain. There is also risk associated with the complex system of ditches, swales and overflow points in the mound drainage which is designed to replicate the natural hydrological regime. NRW has limited confidence in the ability of this system to meet design objectives. NRW considers that further direct mitigation measures should be secured.

4.4.4. We note (Table D9-11) that long-term botanical monitoring and operational monitoring of water quality and quantity will be undertaken. The monitoring should also inform an updated conceptual site model which should be agreed with NRW and used to inform detailed mitigation measures.

4.4.5. The air quality impact assessment predicts there will be exceedances of the air quality thresholds for NOx and nitrogen deposition at Tre’r Gôf SSSI. NRW advise that the specified mitigation measures, including cutting and removal of vegetation litter with consideration of the sensitivity of the designated features, should be undertaken to offset air quality impacts.

- Tre’r Gôf SSSI Compensation

4.4.6. NRW notes the SSSI compensation proposals outlined in ES Appendices D9-24. NRW has previously advised HNP (letter to HNP dated 8/12/2018) that a number of factors will be considered when assessing the sufficiency of proposed compensation to offset damage to the SSSI interest. These factors include the quantity of proposed compensation (extent), the quality of proposed compensation (wetland type), distance from the affected SSSI, the potential connectivity with existing wetland areas, the likelihood / feasibility of successful habitat creation and the arrangement for long-term monitoring, management and security of the compensation.

4.4.7. Based on the information presented in the ES and supporting information, NRW is not able to conclude that the proposed compensation package for Tre’r Gof SSSI will deliver adequate quantity or quality of replacement habitat. No hydrological baseline information for the Cors Gwawr and Cae Canol-dydd compensation sites is provided in the ES; however, this information is critical in informing the likely success of the compensation.

- Cae Gwyn SSSI

4.4.8. Water quality impacts from parking and mounding in the vicinity of Cae Gwyn SSSI will need to be carefully managed to ensure the SSSI is not damaged. We refer to our comment above in section 2 in relation to the CoCP which will need to be agreed with NRW.

4.4.9. ES chapter D5 identifies air quality threshold exceedances at Cae Gwyn SSSI, however ES chapter D9 does not fully address how mitigation measures will offset the exceedances.

4.5. European and Nationally Protected Species

4.5.1. NRW has considered the draft mitigation licences submitted as part of the DCO application. NRW advises that the duration of the post-construction monitoring is not satisfactory for evidencing the successful mitigation in terms of maintaining or restoring the current conservation status of the species to favourable levels.

4.5.2. ES Appendix D9-21 (Draft Great Crested Newt (GCN) Mitigation Licence) identifies a GCN translocation area. The applicant will need to ensure that the site can be secured and can be managed as a GCN receptor site.

4.5.3. NRW advises that the detailed phasing and the final layout of the Landscape and Habitat Management Strategy will need be agreed with the consenting authority(ies), and NRW as a statutory consultee, to ensure that the project is not detrimental to the maintenance of the Favourable Conservation Status of the affected protected species.

4.6. Marine Environment

- Benthic habitats

4.6.1. NRW advises that there is insufficient evidence presented to demonstrate that the cumulative effects of the project on benthic habitats are insignificant. Further consideration of mitigation and/or enhancement measures will be required.

4.6.2. The ES does not fully assess the potential risks posed by the introduction of Invasive Non-Native Species. The presence of the sea squirt Didemnum vexillum in Holyhead is a particular concern. The applicant will need to ensure there is a joined-up approach with the Port of Holyhead with respect to ensuring risks posed by this species (and others) are minimised as far as possible.

4.7. Protected Landscapes

4.7.1. NRW agrees with the conclusions in the ES and its assessment of Landscape and Visual effects relating to the Ynys M?n / Isle of Anglesey Area of Outstanding Natural Beauty (AONB). NRW advises detailed proposals will need to be submitted to ensure mitigation of impacts upon the AONB are fully developed. NRW considers detailed proposals are required to confirm that the power station’s landscape and visual integration with the AONB has been developed to best effect. If the project is approved, the scope, requirements and acceptability of this information should be agreed with the consenting authority(ies), and NRW as a statutory consultee.


4.1. We refer you to our comment in section 2 in relation to the Code of Construction Practice and Sub-CoCPs.


5.1. Flood Risk

5.1.1. NRW has significant concerns that the proposal will result in unacceptable increased flood risk.

5.1.2. This site will suffer from significant flood depths and will fail the criteria of TAN15 of being flood free during the 1% event (1 in 100 year) (para A1.14 of TAN15). The site will also flood on more frequent events (1:20) and it is unclear if any mitigation is proposed or feasible. The FCA/hydraulic modelling has also identified flood depths greater than 2m at the 0.1% Annual Exceedance Probability (1 in 1,000 year) event in the south-central area of the Park and Ride.

5.1.3. The proposal is not compliant with TAN15 in terms of flood risk (tables A1.14 nor A1.15). Mitigation measures have either not been provided, are unclear, or no evidence has been provided to demonstrate that the proposal would comply with TAN15. We advise that the FCA is unacceptable to NRW in terms of addressing the flood risks of the proposal. The Lead Local Flood Authority should also comment on the pluvial flood risks which shows the application site flooding to considerable depth and poses a risk to users and their property.

5.2. Foul Drainage

5.2.1. Toilet facilities and sewage treatment are briefly discussed, but no details are provided as to the proposed sewage treatment and volumes generated. Limited assessment of the sewage treatment options has been carried out. As the site is upstream of Llyn Traffwll SSSI, we have concerns regarding additional nutrients discharging into the watercourse. The discharge would require an Environmental Permit from NRW.

5.3. In relation to the comments made above on flood risk (5.1) and foul drainage (5.2), NRW advises that the applicant must ensure that it will be possible to incorporate all mitigation measures within the application boundary and demonstrate how such measures can be secured.


6.1. Flood Risk

- Valley (Section 1)

6.1.1. NRW has significant concerns that the proposal will result in unacceptable increased flood risk.

6.1.2. The tidal defence only provides protection up to and including the 1/1000-year tidal flood level (0.1% AEP). However, the tidal defence embankment would be overtopped when climate change is also considered, for the lifetime of the development. Overtopping is more likely to lead to breaching from levels exceeding crest heights. The impact the works would have on flood risk elsewhere should a failure (breach) of the tidal defence occur has not been assessed. Mitigation has been provided for other modelled scenarios but the tidal breach scenario has not been assessed, as we have requested. NRW advise that should a failure (breach) occur to the defences affording tidal protection to the area, then existing properties (and land) may be inundated to deeper flooding following the development in Section 1.

- Llanfachraeth (Section 3)

6.1.3. Following the development, the water level immediately upstream of the bypass increases in the Afon Alaw and Afon Llywenan in all flood events. The increase for the ‘design event’ (table A1.14 in TAN15) for the 1% AEP plus climate change is 0.09m and 0.02m respectively. Table G8-8 refers to mitigation which would involve “…minor ground re-profiling …… without increasing flood risk elsewhere…..”. It has not been demonstrated that this can be achieved. It is also unclear if this can be carried out within the current DCO application limits, and NRW therefore advise it is unclear whether the proposal is compliant with TAN15.

6.2. European and Nationally Protected Species

6.2.1. NRW advises that land identified for mitigation and/or compensation measures with respect to protected species will need to be secured. We also advise that long-term monitoring as well as management/wardening will be required, and appropriately secured through the DCO, to ensure that the project will not be detrimental to the maintenance of the Favourable Conservation Status of the affected species.


7.1. Code of Construction Practice

7.2. We refer you to our comment in section 2 in relation to the Code of Construction Practice and Sub-CoCPs.


8.1. NRW is satisfied that this advice is consistent with its general purpose of pursuing the sustainable management of natural resources in relation to Wales, and applying the principles of sustainable management of natural resources. In particular, NRW acknowledges that the principles of sustainable management include taking account of all relevant evidence and gathering evidence in respect of uncertainties, and taking account of the short, medium and long term consequences of actions. NRW further acknowledges that it is an objective of sustainable management to maintain and enhance the resilience of ecosystems and the benefits they provide and, in so doing meet the needs of present generations of people without compromising the ability of future generations to meet their needs, and contribute to the achievement of the well-being goals in section 4 of the Well-being of Future Generations (Wales) Act 2015.


Marine Licensing Comments

DCO Requirements

1. NRW has concerns that works which are licensable under the Marine and Coastal Access Act 2009 are also contained within the requirements of the draft Development Consent Order, with the identification of NRW as a discharging authority for such works. NRW will make further representations and would expect detailed scrutiny of these issues during the examination.