Piblinell Carbon Deuocsid HyNet North West

Nid safbwyntiau’r Arolygiaeth Gynllunio yw’r rhai a fynegir ar y dudalen hon. Yr hyn a ddangosir yma yw cynnwys a gyflwynwyd i’r Arolygiaeth Gynllunio gan y cyhoedd a phartïon eraill â buddiant, sy’n rhoi eu barn ynglŷn â’r cynnig hwn.

Piblinell Carbon Deuocsid HyNet

Derbyniwyd 17/07/2023
Gan Natural Resources Wales


CR2 Dear Sir/Madam, PIBLINELL CARBON DEUOCSID HYNET ARFAETHEDIG / PROPOSED HYNET CARBON DIOXIDE PIPELINE NATURAL RESOURCES WALES’ RELEVANT REPRESENTATION FOR CHANGE REQUEST 2 This letter comprises Natural Resources Wales’ (NRW) relevant response for the Applicant’s Change Request 2 for the above proposal. Our comments are made without prejudice to any further comments NRW may wish to make in relation to this application and examination whether in relation to the ES, provisions of the draft DCO and its Requirements, SoCG or other evidence and documents provided by Liverpool Bay CCS Ltd. and their consultants (‘the Applicant’), the Examining Authority or other interested parties. NRW is 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. It is consulted in respect of this change request under the Infrastructure Planning (changes to, and revocation of, Development Consent Orders) Regulations 2011. In addition, NRW exercises distinct and separate functions under legislation as detailed in the cover letter of NRW’s Deadline 1 Written Representations [REP1-071]. Our Relevant Representation for Change Request 2 is contained within Annex A of this letter. In summary, NRW has no objection to the two proposed changes. In particular, we would welcome Change 1, namely the alternative embedded pipe bridge option for crossing Alltami Brook. Of relevance to Change 1, being the alternative crossing option presented within Change Request 2, NRW acknowledges receipt of the Applicant’s Hydrological Impact Appraisal [REP5-014] and Article 4(7) Water Framework Directive Derogation report [REP5-016] and will be providing advice on these documents separately into the examination. 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. Please do not hesitate to contact Chris Jones should you require further advice or information regarding these representations. Yours sincerely, Chris Jones Uwch Gynghorydd – Cynllunio Datblygu / Senior Advisor – Development Planning Cyfoeth Naturiol Cymru / Natural Resources Wales [CONTINUED]   ANNEX A: NRW’s Relevant Representation for the proposed HyNet Carbon Dioxide pipeline Change Request 2 1) Water Framework Directive 1.1 NRW raised concerns in its Written Representation [REP1-071] that the Applicant’s submitted WFD compliance assessment [APP-165] does not contain sufficient evidence to demonstrate that "potential construction and operation impacts are unlikely to cause a deterioration in the status of quality elements or overall status at the Wepre Brook water body scale with the mitigation within the CEMP, REAC and monitoring measures implemented". Further, in respect of para 5.5.20 there is insufficient evidence to demonstrate that "The DCO Proposed Development therefore would not compromise the ability of the water bodies potentially impacted to achieve Good Ecological Potential/Status." 1.2 NRW considers that there may be deterioration of Wepre Brook water body, as a result of the proposed open-cut crossing of Alltami Brook. This is because there is a risk that excavating bedrock for the proposed Alltami Brook open-cut crossing could create a pathway for surface water to be lost to the ground/contaminated mine workings; this could cause water courses to dry up downstream. This continues to be NRW’s position with the Applicant’s preferred open-cut crossing option. 1.3 However, based on the information submitted in support of Change Request 2 NRW concur with the following statement within Appendix 18.3 Water Framework Directive Assessment Addendum [CR2-019] for the alternative embedded pipe bridge option: “Detailed assessment of the proposed design option PS25 concludes that the Alltami Brook embedded pipe bridge option is WFD compliant” (para. 1.4.13)”. 1.4 NRW therefore considers that the alternative embedded pipe bridge crossing option, would address the concerns regarding the risk of surface water flow loss from the Alltami Brook currently presented by the Applicant’s preferred open-cut crossing option, as raised in our Written Representation. Consequently, NRW does not consider that the derogation provisions under the Water Environment (Water Framework Directive) Regulations 2017 would need to be engaged in the event that the Applicant elects to proceed with this option. Our detailed comments regarding this are provided below.1.1: Hydrogeology 1.1.1 Section 2.1.9 of the 2023 Environmental Statement Addendum Change Request 2 [CR2-017] states the following with regards to the alternative embedded pipe bridge crossing option design: “It is expected that piled foundations will not be required due to the shallow bedrock within the gorge; however, piled foundations for the abutments, as an alternative to standard shallow and direct foundations, could be required depending on the actual soil conditions and the associated mechanical properties. This will need to be further investigated during detailed design”. 1.1.2 The main difference between the open-cut option versus the embedded pipeline option is largely the nature and extent of construction excavation and whether the operational performance, in terms of the potential for integrity loss of a grouted open excavation over time under the open-cut option, could result in some flow loss from the Alltami Brook to the underlying bedrock. This is in direct contrast when considering if the same risk applies to the foundations for the embedded pipeline option, which are not within the Alltami Brook channel bedrock and therefore do not possess a potential for brook flow loss. 1.1.3 A review of the proposed foundations [CR2-021] shows that the nature of the proposed excavation appears to be significantly reduced and would not occur within the channel bedrock of Alltami Brook but rather within the adjacent banking; it therefore does not pose a potential risk for surface water flow loss from the brook, as a result of encountering a transmissive fracture(s) for example. 1.1.4 NRW acknowledges that the embedded pipe bridge option includes the potential for piles to be required depending on the load-bearing properties of the local bedrock for supporting the bridge, and this would be further investigated during detailed design. However, such piling is considered to be far less intrusive in comparison to the bedrock excavations within the brook channel proposed for the open-cut option (which we note would affect a 4m length of channel). 1.1.5 In summary, based on the evidence available, NRW advises that the embedded pipe bridge option does not present a risk in terms of surface water flow loss from Alltami Brook to the underlying bedrock. In contrast, the open-cut option presents a risk for surface water flow loss because bedrock excavation would occur directly within a 4m extent of the brook channel itself as opposed to within the adjacent banking. 1.2: Geomorphology 1.2.1 From a geomorphological perspective, NRW has no objection to the proposed embedded pipe bridge crossing given the current risk of surface water flow loss associated with the Applicant’s preferred open-cut option within the channel bedrock. 1.2.2 During temporary works associated with any diversion of the Alltami Brook, NRW advises that sandbags should be replaced with bags of washed gravels (Visqueen wrapped if needed) such that should a bag split only habitat-beneficial gravels would enter the watercourse and not potentially habitat-smothering sands. 1.3: Hydrology 1.3.1 Based on the information submitted, NRW considers that the embedded pipe bridge option would remove the risk of surface water from Alltami Brook being lost to the ground as a result of the pipeline crossing, which could otherwise be caused by the required excavation into the bedrock under the Alltami Brook for the Applicant’s preferred open-cut crossing option. In the absence of any ground investigation data from the site to verify the Applicant’s assessment conclusions regarding this risk, we consider that the embedded pipe bridge option would enable surface water quantities in the Alltami Brook watercourse to remain protected. 2) Flood risk 2.1 NRW has reviewed the information submitted in support of Change Request 2 including the ES Addendum Change Request 2 - Appendix B – Technical Appendices Addenda [CR2-019], specifically Appendix 18.5 Flood Consequences Assessment. 2.2 NRW has previously provided advice on the flood risk design parameters for an alternative embedded pipe bridge crossing over Alltami Brook in our Written Representations (REP1-071, paragraph 3.8), advising that the soffit level of the bridge should be set 300mm above the flood level for the 1% Annual Exceedance Probability (AEP) (1 in 100) event with an allowance for climate change. Whilst this is acknowledged by the Applicant this approach has not yet been adopted due to the absence of any detailed flood modelling data for the Alltami Brook watercourse. 2.3 Instead, a qualitative approach has been undertaken and the proposal is for the soffit level of the bridge to be set 1500mm above the dry weather flow water level of the watercourse. Based on the justification provided in the FCA (local topography and the culvert upstream controlling flows) NRW considers this to be a reasonable approach. 2.4 The Applicant also states that it is not expected that the structure (including its abutments) would result in increased flood risk elsewhere due to the topography of the deep channel and the modelled extents shown on the Flood Map for Planning (FMfP). Again, NRW considers this is a reasonable conclusion based on readily available information. 2.5 NRW is also satisfied with the suggested maintenance requirements for the structure, from a flood risk perspective, as outlined in Section 2.1.16 of the ES Addendum [CR2-017]. 2.6 The FCA recommends undertaking a hydraulic model for the section of Alltami Brook to confirm the design criteria for the embedded pipe bridge option as part of the detailed design stage (paragraph 1.5.36). Whilst NRW considers the approach taken to be reasonable given the lack of any detailed flood modelling data, we concur that detailed hydraulic modelling should be undertaken at the detailed design stage in order to quantify flood levels. This would ensure that the soffit of the bridge is raised above the design flood level and enable the potential impacts on flood risk elsewhere to be fully understood. However, we advise that this could result in further design changes post any DCO consent and some of the parameters shown on the ‘Indicative Arrangement’ plan [CR2-021] may need to be amended to reflect the modelling outputs, including the minimum clearance above water levels and the location of the abutments. 2.7 NRW notes that sub-paragraph (8) of Requirement 4 [REP4-008] aims to provide a suitable mechanism within the DCO to secure the submission of the above detailed design information for approval prior to construction. However, we advise that the following minor amendments are made to the wording of this requirement, as underlined below: “8) Where the crossing of Alltami Brook uses an embedded pipe bridge (Work No. 43E), the details submitted under sub-paragraph (5) must be accompanied by a flood consequences assessment showing the maximum water level reached in a 1 in 100 year event plus 20% climate change scenario. The soffit level of the embedded pipe bridge over the Alltami brook must be set no less than 300 millimetres above that maximum water level. The flood consequences assessment must also demonstrate that the impacts of the proposal on flood risk elsewhere can be managed to an acceptable level”. 2.8 NRW also notes that the Outline Construction Environmental Management Plan [REP4-237] and Register of Environmental Actions and Commitments [REP4-235] include reference to the need for hydraulic modelling (D-WR-076) and for the bridge design to provide a minimum freeboard of 300mm above the 1% AEP event with an allowance for climate change (D-WR-075). 2.9 However, contrary to paragraph 1.5.18 of the ES Addendum Change Request 2 - Appendix B - Technical Appendices Addenda [CR2-019] and the subsequent wording of D-WR-076, please note that the construction of the embedded pipe bridge would not require a Flood Risk Activity Permit (FRAP), as the Alltami Brook watercourse is not a designated main river. The works (including any temporary works required to facilitate construction) may require an Ordinary Watercourse Consent (OWC), which would be administered by the Lead Local Flood Authority (LLFA). Furthermore, the final design of the structure should be approved by the LLFA since it would cross an Ordinary Watercourse. We therefore advise consultation with the LLFA in this regard. 2.10 In relation to the proposed changes to land plots (Change 2, CR2-016], NRW advises that a FRAP would be required for any additional crossings on Pentre Drain North, as this is a designated main river. 3) Protected Species 3.1 NRW has no objection to either of the two proposed scheme amendments from a protected species conservation perspective. 4) Fisheries 4.1 NRW has no objection to either of the two proposed scheme amendments from a fisheries perspective.