Environment Agency
"APPLICATION BY HIGHWAYS ENGLAND FOR AN ORDER GRANTING DEVELOPMENT CONSENT FOR THE A47/A11 THICKTHORN JUNCTION PROJECT Please find below our relevant representation for the A47/A11 Thickthorn Junction project. The Role of the Environment Agency The Environment Agency is a statutory consultee on all applications for development consent orders. We have a responsibility for protecting and improving the environment, as well as contributing to sustainable development. We have three main roles: (i) We are an environmental regulator – we take a risk-based approach and target our effort to maintain and improve environmental standards and to minimise unnecessary burdens on business. We issue a range of permits and consents. (ii) We are an environmental operator – we are a national organisation that operates locally. We work with people and communities across England to protect and improve the environment in and integrated way. We provide a vital incident response capability. (iii) We are an environmental advisor – we compile and assess the best available evidence and use this to report on the state of the environment. We use our own monitoring information and that of others to inform this activity. We provide technical information and advice to national and local governments to support their roles in policy and decision-making. One of our specific functions is as a Flood Risk Management Authority. We have a general supervisory duty relating to specific flood risk management matters in respect of flood risk arising from Main Rivers or the sea. Overview and issues of concern Our relevant representation outlines where we consider further work, clarification or mitigation is required to ensure that the proposal has no detrimental impact on the environment. We have highlighted that we are generally satisfied with the assessment of, and proposed approach to managing fluvial flood risk across the scheme. Some additional detailed survey and modelling work is being undertaken by the Applicant, which we will need to review and approve. There are also some outstanding actions for the Applicant to address in respect of the flood model which supports the flood risk assessment. Our position is therefore subject to a satisfactory review of this further work. We are broadly satisfied with the proposed Cantley Stream realignment, subject to some points of clarification and a future review of the detailed design. In general we are also satisfied with the overall approach taken to date and the mitigation proposed in respect of protecting surface water quality and groundwater resources. We have made a number of observations in respect of these issues and have highlighted that we will need to review further assessments and the detailed proposals prior to development commencing. We have requested an amendment to Requirement 6, and that we are added as a named consultee to Requirements 4 and 8. Please do not hesitate to contact me if you require any further information. We look forward to continuing to work with the applicant to resolve the matters outlined within our relevant representation to ensure the best environmental outcome for the project. Yours faithfully Martin Barrell Planning Specialist Environment Agency 1.0 Document 3.1 Draft Development Consent Order (DCO) 1.1 Requirement 4 requires the preparation of an Environmental Management Plan (EMP) and associated documents. The EMP is a mechanism to ensure the delivery of mitigation measures during the construction phase, as outlined in the Environmental Statement, including those in Chapter 13 Road drainage and the water environment. Although we are generally satisfied with the approach taken in identifying the potential adverse effects of the proposed scheme on surface water quality and groundwater resources, and with the mitigation outlined to date, the Environment Agency should have the opportunity to review and comment on the detailed proposals prior to construction. 1.2 The Environment Agency should be included as a named consultee in respect of Requirement 4, for matters relevant to our remit. 1.3 We support the inclusion of Requirement 6 Contaminated land and groundwater, and we welcome the inclusion of the Environment Agency as a named consultee. However, the proposed wording should be amended. The determination of the need for remediation in part (2) should be based on a consideration of the risk assessment by all parties, rather than determined solely by the undertaker. Additionally, and also in respect of part (2), remedial measures should be taken to render the land fit for its intended purpose and to prevent any impacts on controlled waters. 1.4 Requirement 8 is concerned with Surface and foul water drainage. As detailed below, we are generally satisfied with the approach proposed to date. However, work on the detailed drainage design is ongoing. It will be important for us to review and confirm that the detailed proposals are acceptable. 1.5 The Environment Agency should therefore be a named consultee in respect of Requirement 8 Surface and foul water drainage system. 1.6 Regarding the procedure for discharge, we note that Requirement 17 Details of consultation, states that parties will be given not less than 10 business days to respond to any consultation. We would request that this be amended to 21 days, to allow us sufficient time to consult internally and provide a comprehensive response. 2.0 Document 3.3 Consents and Licences Position Statement 2.1 We note the inclusion of Appendix A - Table of Consents and Agreements as required from consenting authorities, including the Environment Agency. We welcome early discussions on these authorisations and note that progress is to be reported in a Statement of Common Ground. 2.2 With reference to the section concerning ‘Diversion of watercourses’, we would highlight that works to realign Cantley Stream may require a transfer licence from the Environment Agency. An impoundment licence may also be necessary if a structure is required that restricts flow. 2.3 On the issue of ‘Waste and Materials’, it should be noted that an Environmental Permit will be required for the importation and treatment of waste material falling outside the scope or limits detailed in either a Regulatory Position Statement or a waste exemption. In respect of ‘Waste Materials’, the consenting authority for certain mobile plant permits such as concrete crushers is the relevant local authority, and therefore they should be listed along with the Environment Agency. 3.0 Document 6.1 Environmental Statement Chapter 8 - Biodiversity 3.1 We are satisfied, for matters within our remit, that the ecological surveys are complete and correct in terms of their timings, and that an adequate number of surveys were completed during the survey season by a suitably qualified and experienced ecologist. 3.2 This chapter highlights that ecological enhancements are to be incorporated as part of the realignment of Cantley Stream, including the provision of additional habitat suitable for water voles. We note that all mitigation will be detailed and implemented as part of the Record of Environmental Actions and Commitments (REAC) within the Environmental Management Plan (EMP). The EMP falls under Requirement 4, and as highlighted in 1.2 (above) we would wish to be consulted on the relevant sections of the EMP. 3.3 Further comments on the proposed realignment of the Cantley Stream are included below in section 7 in response to the first iteration EMP. 4.0 Document 6.1 Environmental Statement Chapter 9 – Geology and Soils 4.1 We recognise the rationale for the classifications regarding the sensitivity of receptors and magnitude of impacts presented in Table 9-4 and 9-5 (and repeated in Table 13.1 & 13.2 of Chapter 13 Road drainage and the water environment). However, it will be essential for the project to apply the principle that no private drinking water supplies can be derogated, even temporarily, without the prior consent of the owner and the provision of mitigation measures. 4.2 With reference to paragraph 9.4.27, we would highlight that locating a drainage pond over an infilled gravel pit would not be appropriate unless the fill can be proved to be inert. We therefore welcome the commitment to a full investigation of the landfill and infilled pit, to better inform Tables 9-10 (Determination of magnitude of potential impact), 9-12 (Determination of residual effects significance) and the Materials Management Plan. 4.3 We also welcome and support the undertaking of further assessments of linkages and mitigation for potential on-site and off-site contaminated land sources proposed in Section 6.11 of ES Appendix 9.3 – Preliminary Sources Study Report Part 1 of 2. 4.4 As highlighted above, we support the inclusion within the draft DCO of Requirement 6 Contaminated land and groundwater, but have suggested two amendments to the proposed wording. We welcome the inclusion of the Environment Agency as a named consultee in respect of that Requirement. 5.0 Documents under 6.3 Environmental Statement Appendices relating to ES Chapter 10 – Material Assets and Waste 5.1 6.3 ES Appendix 10.2 – Waste disposal assessment. In respect of Table 1: Preliminary waste assessment summary, we would highlight the following in relation to the Cantley Lane landfill and the classification included under Domestic household waste: Reference has been made to LoW codes 17 05 03* and 17 05 04 for excavated waste soil. Based on the description provided from TP11, TP27 and TP29, once assessed in accordance with Technical Guidance WM3, some excavated waste may be more appropriately classified under additional Chapter 17 codes, such as, but not limited to the following examples: o 17 01 06* mixtures of, or separate fractions of concrete, bricks, tiles and ceramics containing hazardous substances o 17 01 07 mixtures of concrete, bricks, tiles and ceramics other than those mentioned in 17 01 06 o 17 09 03* other construction and demolition waste (including mixed waste) containing hazardous substances o 17 09 04 mixed construction and demolition wastes other than those mentioned in 17 0 9 01, 17 09 02 and 17 09 03 We would highlight that, along with the LoW code, the Duty of Care paperwork is to provide an accurate description of any waste removed from the site. 5.2 6.3 ES Appendix 10.3 – Outline site waste management plan (SWMP). With reference to paragraph 10.1.29 (anticipated waste types), we would recommend that the final SWMP includes a section on managing excavated waste from the Cantley Lane landfilled waste area and the infilled gravel pit east of Cantley Lane South. We would expect this section to reference the further waste assessments required on the landfilled/infilled waste identified in Table 1 of Appendix 10.2 Waste Disposal Assessment, and how this activity will be managed to protect the environment and prevent harm to human health. Factors such as, but not limited to, those listed below should be considered: o Preventing the creation of pathways from any contaminated land to sensitive environmental receptors, o managing to minimise impact on amenity and o ensuring that the remaining waste is left in a manner that prevents and minimises pollution. 5.3 Regarding paragraph 10.1.39 of the outline SWMP, we recommend that the final SWMP refers to an accurate description of the waste when referring to Duty of care documentation, such as transfer or consignment notes rather than the type of waste. 5.4 We note that the SWMP will be included as part of the Second Iteration of the EMP. We would wish to be consulted on the SWMP, and therefore, as highlighted above we should be included as a named consultee in respect of Requirement 4. 6.0 Document 6.1 Environmental Statement Chapter 13 – Road Drainage and Water Environment and Appendices 6.1 In respect of surface water quality, we are satisfied with the consideration of potential issues to date and with the general principles of the proposed mitigation measures for both the construction and operational phases. As previously highlighted, we would want to review the detailed proposals. 6.2 With regards to water quality and the water framework directive (WFD), we agree with the waterbodies considered and support the mitigation measures referenced in section 13.9 to protect water quality. The WFD considerations included in this section and elsewhere in Chapter 13 are fairly comprehensive. However there is often mention of effects on the ‘overall WFD status of the waterbodies’. This is the case, for example, in Table 13.2 Estimating the magnitude of an impact on an attribute. A key WFD requirement is for no deterioration in any of the individual elements that make up the waterbody classification, as well as no deterioration in the overall classification. It should therefore be ensured that the individual elements are also assessed and considered during the detailed design process. 6.3 We note that paragraph 13.9.44 states that for the Cantley Stream realignment, the detailed design including water vole enhancements will be agreed in consultation with the Environment Agency, Norfolk County Council and other stakeholders. We welcome this, although the mechanism for this consultation should be confirmed. As highlighted above, the realignment works may also require water resources licences from the Environment Agency. 6.4 In respect of groundwater resources and quality, and Table 13.1 & 13.2 (importance of an attribute and magnitude of impact), we would repeat our comment under 4.1 above. No private water supply can be derogated as a result of the works or operation of the scheme, even temporarily, without the prior written consent of the owner and the provision of mitigation measures. 6.5 Regarding section 13.8 and potential impacts during construction, we have specific requirements for any proposed horizontal directional drilling (HDD). A detailed prior assessment of the strata to be encountered should be undertaken. Inert drilling muds (as approved by the Environment Agency), should be used and drilling mud monitoring put in place and breakout plans prepared. HDD works must be undertaken in a way that precludes any alteration to the existing degree of hydraulic continuity between strata or surface water features. We would want to review the HDD method statements. 6.6 With reference to paragraph 13.8.26, we note that the A11 – A47 connector road may intercept and expose the top of the chalk bedrock. We welcome the undertaking in paragraph 13.9.19 to avoid infiltration to ground in this area and the commitment to complete construction method statements and consult on HDD works (paragraph 13.9.21). We also welcome the commitment to prepare piling risk assessments (13.9.24), and the undertaking to monitor at water features at risk (13.9.26). 6.7 We welcome the use of carrier drains in sensitive areas, as outlined in paragraphs 13.9.28 & 29. We would like the opportunity to review the areas where both carrier drains and filter drains are proposed after further ground investigation works have been completed. We would like further information on the risk to groundwater from hydrocarbon spills, in terms of both free product and dissolved phases. We would also like the opportunity to review further details on the operational subsurface drainage when available, as referred to in paragraph 13.9.49. 6.8 With reference to paragraph 13.9.50, the minimum thickness of unsaturated zone for areas where infiltration is shown to be acceptable will be 1.2 metres, not 1m as stated. A thickness of 2 – 5 m is preferable. 6.9 With reference to paragraph 13.9.51, we are pleased to note that baseline groundwater quality monitoring will continue. 6.10 We also welcome the proposals to undertake a water features survey along with hydrogeological risk assessments (HRA) for any abstractions and groundwater dependent terrestrial ecosystems down gradient of dewatering, HDD or other intrusive works. 6.11 Overall, we are generally satisfied with the proposals and information outlined in the Drainage Strategy Report (Document 6.3, ES Appendix 13.2). But as indicated, we will need to review and confirm that further assessments and the detailed proposals for both the construction and operational stages are acceptable. As highlighted above with regards to the draft DCO, the Environment Agency should therefore be a named consultee in respect of Requirement 8 (Surface and foul water drainage system), and, for matters relevant to our remit, Requirement 4 (Environmental Management Plan). 6.12 In respect of the Groundwater Assessment (Document 6.3, ES Appendix 13.2), we welcome the full assessment of potential impacts in Table 3.1. 6.13 The drainage in catchment B is of concern given the thin unsaturated zone and the presence of proximal abstractions, as noted in the Table 4.2. We welcome the proposed ground investigations (GI) to fully assess potential impacts. 6.14 As highlighted within the Groundwater assessment document, further consultation with the Environment Agency on the potential impacts on groundwater will be required. 6.15 Regarding the Water Quality Assessment (Document 6.3, ES Appendix 13.4), we are satisfied with the assessment for surface water and details of the measures to mitigate risks. We look forward to reviewing the detail. 6.16 In respect of fluvial flood risk, we note that paragraph 13.9.40 of the ES states that current assessments have shown that there is an increase in flood risk to a residential property of up to 15mm, and that property level protection is proposed as mitigation. It is highlighted that further survey work and flood modelling is being carried out to confirm the flood risk impacts and inform the required mitigation. This further work should form part of an updated Flood Risk Assessment, which we should be given the opportunity to review and approve. 6.17 Paragraph 13.9.42 states that “changes in the floodplain level ranged from a reduction of up to 250mm and an increase of up to 100mm” and “The magnitude of impact ranges from major adverse to major beneficial”. This point then goes on to state that other than the residential property discussed in the point above, the receptors impacted are “classified as ‘less vulnerable’ (agricultural land) and ‘water compatible’ (amenity) under the NPPF”. In concluding this point it is stated that “Overall, given the majority of areas are of moderate magnitude it is considered the significance of effect is classed as moderate rather than major under DMRB LA104”. 6.18 We also note that point 13.10.6 of chapter 13 of the Environmental Statement also states “The effects range from moderate beneficial to moderate adverse significance depending on the location within the floodplain”. Table 13.1 provides the criteria for estimating the importance of water environment attributes and Table 13.2 provides the criteria for Estimating the magnitude of an impact on an attribute. These tables have been used in assessing the impact of the changes to flood risk. 6.19 The standalone Flood Risk Assessment (FRA) is included as document 6.3 Appendix 13.1. We are generally satisfied with the FRA and with the proposed approach to managing fluvial flood risk across the scheme. However, this position is subject to a satisfactory review of the further information due to be provided, as outlined below. 6.20 Section 4.4.2 of the FRA states “Agreement that the proposed new larger culvert beneath Cantley Lane removes the throttling effect on flows / levels and, due to the negligible changes in downstream flood risk, removes the requirement to provide any compensatory flood storage”. We agree that no compensatory storage will be required, providing that any further assessments continue to show that the project has no significant adverse impacts on flood risk. 6.21 As highlighted above, the FRA indicates that there may be increased flood risk to a dwelling (classified as ‘more vulnerable’) as a result of the proposed scheme. We note that various options to mitigate the increase in flood risk have been considered, including whether compensatory flood storage could be provided. Our understanding is that the assessment concluded that compensatory flood storage did not appear to be an appropriate solution, but that property level protection may be proposed if required. 6.22 Sections 8.2.6 & 8.2.11 of the FRA state that “Confirmation of the impact and, therefore the mitigation, is subject to additional survey and modelling to better predict the impacts in this location”. As mentioned above, the outcome of this additional work will should form an update to this FRA, which should be reviewed and approved by us. 6.23 Section 8.2.12 of the FRA states “Due to the proposed removal of the existing Cantley Lane South culvert and the realigned stream there are changes in the patterns of flood risk within the floodplain affecting agricultural land and amenity areas (classed as ‘less vulnerable’ and ‘water compatible’ under the NPPF). Following the initial impact assessment of removing the existing Cantley Lane South culvert throttle, it was agreed with Norfolk County Council and the Environment Agency in August 2020 that there is no requirement to provide compensatory flood storage upstream of Cantley Lane South culvert.” As above, agreement is based on further assessments continuing show no significant adverse effects on flood risk. 6.24 The Environment Agency has previously reviewed the flood modelling work completed by the Applicant to inform this FRA. At the time of submission, there remained some outstanding model review actions needing to be resolved before the suitability of the assessment could be confirmed. A demonstration that these required actions have been addressed should be submitted along with the details and conclusions of the additional survey and modelling work currently being undertaken. 6.25 Following the further survey and flood modelling work, if any increases in flood risk as a result of the scheme are identified, it should be clearly documented as to why the increase cannot be prevented and how any impacts will be managed. Where decisions on the significance of any flood risk impacts on receptors have been made, it should be clear how the assessment was undertaken and why the conclusion on significance was reached. 7.0 Document 7.4 Environmental Management Plan (First Iteration) 7.1 With reference to paragraphs 1.1.5 and 1.1.6, we note that there is no reference to a Temporary surface water drainage plan being prepared as part of the EMP. However, it is listed as a plan to be prepared in the draft DCO under Requirement 4, and is referred to elsewhere within the EMP. 7.2 As highlighted above, the Environment Agency should be included as a named consultee in respect of Requirement 4, to enable us to review and comment on relevant documents. 7.3 Plans and strategies forming part of the EMP that we would wish to review include: the Landscape and ecology management plan, Temporary surface water drainage plan, Water monitoring and management plan, Site waste management plan, Soil management plan and Materials management plan. 7.4 We have reviewed Section 3 and Table 3.1: Record of Environmental Actions and Commitments (REAC). We have the following comments at this time: 7.5 B15 – we support the approach proposed to protect fish caught up in the de-watering of the old channel of the Cantley stream, which include netting and electrofishing to remove fish. We note that full details will be included in the Second Iteration EMP and we would wish to review those details. As highlighted above, consents may be required from the Environment Agency for works associated with the diversion of Cantley Stream. 7.6 Currently, we would highlight that additional checks will be required as water levels are lowered, with individual fish removed and transported upstream. We would like to see the use of a silt curtain or coffer dam at the downstream extent of the old channel to prevent fish kills further downstream as a result of the silt released during fish removal, and in particular as the channel is de-watered. Use of a dissolved oxygen monitor would also be recommended to monitor changes in levels during this activity. 7.7 When the water is diverted into the new channel for the first time, there is likely to be some release of loose surface sediment in to the channel immediately downstream. We would like to see that there are measures in place to prevent silt and sediment from being flushed downstream from the new channel. This could include constructing the new stream bed from locally sourced gravels, cobbles, or any gravels that can be retrieved from the original stream bed. We would wish to review this detail in further consultations. 7.8 RD1, RD2 & B3 – we note the measures outlined in relation to pollution prevention and sediment management. As highlighted above, the Environment Agency should be consulted on the water monitoring plans and temporary surface water drainage strategy. 7.9 RD2 – in respect of flood risk, the potential need for property level protection is highlighted. It is not currently clear how the EMP would secure the implementation of such measures. This should be confirmed. 7.10 RD4 – we note the inclusion of the statement that the design of the realigned Cantley Stream will be undertaken in consultation with the Environment Agency, Norfolk County Council and other stakeholders. The mechanism for that consultation should be clarified. 7.11 The full distance of the existing channel being re-aligned and subject to water vole displacement should be compared with the new length of enhanced/restored habitat. It must be ensured that there is adequate provision of alternative habitat for the displaced individuals, especially if there is a delay between displacement activities and establishment of vegetation in the new re-aligned channel. 7.12 The construction period for the proposed scheme seems to offer a relatively short time period in which to establish suitable alternative habitat for displaced water vole, if required. The detailed design must take this into account. 7.13 How the new re-aligned section of channel will be colonised with aquatic and marginal plants has not yet been clarified. The Applicant may be intending to divert some of the flow from the original channel, or bring water in from elsewhere, to wet the new section prior to the final diversion. In that scenario water resource licences may be required from the Environment Agency as highlighted above. Alternatively, the Applicant may be intending to demonstrate that there will be sufficient alternative water vole habitat available to displace/ trap and release into while the new channel re-vegetates. The chosen approach will need to be fully assessed and approved at the detailed design stage. 7.14 RD4 – we also note that the Environment Agency and Norfolk County Council are to agree monitoring requirements for the realigned Cantley Stream as part of the EMP Water monitoring and management plan. We welcome this and look forward to reviewing the plan. Currently, we would highlight that during the process of planning and construction, the water quality of the Cantley Stream should be monitored for changes to pH, turbidity and dissolved oxygen as a minimum. 7.15 RD5 – we note that required WFD mitigation is to be agreed with the Environment Agency. Will this be through consultation on aspects of the EMP, or via other means? 7.16 RD7 to RD10, and RD14 are concerned with the protection of groundwater resources during construction. We are satisfied with the measures proposed, subject to the review of further assessments and details, as outlined. The mechanism for further consultation with the Environment Agency should be clarified. 7.17 We would highlight that the dewatering exemptions noted here; in Table 4-1; and elsewhere in the ES, are only applicable if the works will take less than 6 months. For works over a longer time period, an abstraction licence will be required for any dewatering at rates over 20 m3/d. 7.18 We welcome the proposals to undertake a water features survey along with hydrogeological risk assessments (HRA) for any abstractions and groundwater dependent terrestrial ecosystems down gradient of dewatering, HDD or other intrusive works. 7.19 RD11 – while we are generally supportive of the measures outlined to protect groundwater during operation, we would highlight that the minimum thickness of unsaturated zone for areas where infiltration is shown to be acceptable will be 1.2 metres, not 1m as stated. A thickness of 2 – 5 m is preferable. 7.20 RD15 – we note that this section states that: “Drainage Strategy and Flood Risk Assessment including hydraulic modelling to be approved by the Environment Agency, Lead Local Flood Authority (Norfolk County Council) and Norfolk Rivers Internal Drainage Board”. We welcome this but would highlight that consultation should be progressed and approval obtained as part of the DCO process and not through permit and consent requirements. Cantley Stream is an ordinary watercourse, not a designated main river, and as such the LLFA is the consenting authority for works affecting flows. However, the Environment Agency has reviewed and commented on the FRA due to the presence of fluvial flood risk associated with the Cantley Stream. We should review and approve the FRA to ensure that fluvial flood risk is appropriately managed, and review and approve the drainage strategy to ensure the protection of controlled waters. 7.21 RD17 – as highlighted above, the Environment Agency should review and approve the detailed drainage design. We should be a named consultee in respect of Requirement 8 (Surface and foul water drainage system), and, for matters relevant to our remit, Requirement 4 (Environmental Management Plan). 7.22 Regarding Table 4-1, it should also be noted that the consenting authority in the case of certain mobile plant permits such as concrete crushers is the local authority, and therefore they should be listed along with the Environment Agency. 7.23 With reference to Annex C, we would highlight that we would want to review the Construction method statement for water."
