Representation by Environment Agency (Environment Agency)
- Date submitted
- 18 June 2024
- Submitted by
- Members of the public/businesses
APPLICATION BY FIVE ESTUARIES OFFSHORE WIND FARM LTD FOR AN ORDER GRANTING DEVELOPMENT CONSENT FOR FIVE ESTUARIES OFFSHORE WIND FARM Please find enclosed our relevant representation for the Five Estuaries Offshore Wind Farm 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 made observations about the Land Fall, Ground Water, Biodiversity and Flood Risk and request that additional information will be required for us to be satisfied that risks to the environment are managed. 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 [Redacted] Documents Reviewed APP-039 5.3.2 Flood Risk Assessment Onshore Substation APP-067 6.1.5 Non-Technical Summary APP-086 6.3.4 Onshore Biodiversity and Nature Conservation APP-087 6.3.5 Ground Conditions and Land Use APP-088 6.3.6 Hydrology, Hydrogeology and flood risk APP-129 6. 6, Annex 6.1 Groundwater Risk Assessment129 APP-229 8.1 Cable Statement APP-253 9.21 Code of Construction Practice APP-254 9.22 Outline Landscape and Ecological Management Plan APP-261 9.28 Outline Landfall Methodology APP-266 9.33 Approach to Statements of Common Ground APP-236 9.6 Water Framework Directive Assessment 1. Land Fall 1.1 We have previously reviewed the document 9.28 Outline Landfall Methodology and our requirements for the cables passing under the tidal defence is detailed within our reply document “EA Single Matter Review VE 03-24”. We look forward to reviewing later versions of the Outline Landfall Methodology that will include the project approach to our requirements. 2. Ground Water and Contaminated Land 2.1 We are pleased to see the inclusion of measures relating to unexpected contamination procedure, such as in 6.3.5 Ground Conditions and Land Use paragraph 5.12.6, and 9.21 Code of Construction Practice section 3.17 2.2 Piling: It is noted in 9.6 Water Framework Directive Assessment that Piling may be required, and is scoped in. We wish to be consulted on any piling works that could affect water quality or affect groundwater flow mechanisms. 2.3 with reference to document 9.33 Approach to Statements of Common Ground – Table 1, please add Hydrogeology and Land Contamination to the example topic(s) column as we will continue to be involved with the project. Ground Conditions and Land Use ref 6.3.5 2.4 within the above document 6.5 Assessment criteria, etc. Table and chapter does not include groundwater as a receptor. Trenched and trenchless techniques are likely to intercept GW so these should be included in this element of the risk assessment. Hydrology, Hydrogeology, etc. ref 6.3.6 2.5 Within document A6.7.27- The Thanet Sands are not defined as an unproductive aquifer- it is defined as a secondary A aquifer (cf. Table 2-3 of Vol. 6., Part 6, Annex 6.1 Groundwater Risk Assessment). 2.5 we agree with the assessment that shallow groundwater may be encountered in the secondary aquifers- cover sands, Kesgrave Formation and alluvium document 6.7.32. 2.5 The applicant provides a list of licensed and private water users in the vicinity of the DCO boundary (Tables 6-8 and 6-9) document 6.7.61. Groundwater Risk Assessment Vol. 6, Part 6, Annex 6.1 2.6 The Beyer Formula used for estimating hydraulic conductivity is a lab-based technique, not from field measurements within document 2.3.3. There are inherent limitations and error margins to this formula which have not been stated. If dewatering during construction requires a licence a more rigorous approach to assessing hydraulic conductivity will likely be required. Conceptual site model 3.0 2.7 A similar issue arises with the Sichardt Formula used here. The limitations and assumptions used in estimating the radius of impact are not stated and neither is the empirical calibration factor ‘C’. The applicant uses a conservative approach later to assess this potential radius of impact (250 m) which is a good measure to compensate for the limitations in these two formulas at this stage. If permitting or licensing is required more accurate estimates may be required. 2.8 The conceptual site model otherwise makes good use of publicly available information on the local geology and groundwater levels to later assess hydrogeological impacts. Hydrogeological Impact Assessment 4.0 2.9 The applicant has submitted a thorough list of potentially impacted abstractions (licensed and unlicensed) and risk assessments to those abstractions. Those that have been deemed potentially impacted by trenched and trenchless cable replacement and substation have been noted and steps to improve the impact assessment have been added in 4.3.1 Water Features Survey. We look forwards to seeing the results of this survey and subsequent risk assessment. We would need to be consulted on any followed-up risk assessments, including the results of future work to protect abstractors scoped-in for future assessment. 2.10 The HIA has limited information on the potential for encountering springs or seepage from the superficial deposits (ie. Kesgrave Formation and cover sand) overlying the London Clay. There is the potential for spring lines in the Tendring area where groundwater forms springs at the edge of sand and gravels outcrops which may contribute to flows in local surface water bodies. 2.11 The HIA section otherwise makes good use of publicly available information on the local geology and groundwater levels to later assess hydrogeological impacts. Cable Statement 8.1 Description of onshore cables 4 2.12 The applicant gives a description of the expected dimensions and configuration of cable emplacement and jointing bays. The estimated depths of these workings will need to be detailed to inform the risks to groundwater covered in 6.6 Annex 1 Groundwater Risk Assessment. Construction Code of Practice 9.2 2.13 The applicant states that there may be a requirement for dewatering of excavations. As discussed in relation to the relevant sections of the Groundwater Risk Assessment (6.6, Annex 6), the earlier the likelihood and magnitude of dewatering is estimated, the earlier the risks can be assessed in the event an abstraction licence is required for these works. Outline Landfall Methodology 9.28 2.14 Please amend Figure 3.1 to a high resolution as we are unable to make use of it. HDD water supply 3.5 2.15 The HDD process will require a supply of water- the applicant suggests wither tinkering or abstracting surface water for this purpose. Please be aware abstraction of surface water will require an abstraction licence. Please check the local Abstraction Licensing Strategy for current water availability in the relevant catchments. Risk Assessment Table 4.1 2.16 In the Agency’s scoping response (27 October 2021), there was a request for inclusion of an assessment of that any works at the landfall stage will not create any hydraulic continuity between the sea and underlying strata. 2.17 HDD compound susceptibility to seawater flooding should take into account the possibility of creating hydraulic continuity between seawater and groundwater contained in underlying strata, as recommended in the EA’s Scoping response of 17th October 2021. The risk assessment for ingress of surface and/or groundwater flooding to the HDD entry compound shows the applicant is aware that both types of water may ingress the bay thus pose a risk, but the implied possibility of hydraulic continuity between the two is not mentioned for the jointing bays or HDD. Water Framework Directive Assessment 9.6 2.18 The applicant has scoped in WFD groundwater bodies for assessment. In the event of dewatering I suggest they consult the Essex Abstraction Licensing Strategy in preparation for any dewatering that may occur in the course of construction. 3. Biodiversity 3.1 Impacts on otter and water vole. We consider that the impacts of the development on these species, and freshwater aquatic ecology in general, will be adequately addressed provided the measures set out in the Volume 6, Part 3, Chapter 4 of the Environmental Statement, the Outline Landscape and Ecology Management Plan and the Code of Construction Practice are fully implemented. 3.2 Section 4.10 of the Code of Construction Practice mentions that smaller watercourses may be dammed and overpumped during the construction phase. We recommend that, where watercourses support fish populations, the pumps are guarded by 2mm screens to prevent the entrapment/entrainment of fish. 3.3 Table 7.1 of the Outline Landscape and Ecology Management Plan. Consideration should be given to adding reptiles to the list of species groups that will be re-surveyed in advance of the commencement of construction. This might be particularly useful at locations where incidental records of reptiles were collected and where more structured surveys were not carried out. 4. Flood Risk 4.1 We are currently satisfied with the approach outlined for Flood Risk 4.2 Our maps show the site lies within fluvial and tidal Flood Zone 3a defined by the ‘Planning Practice Guidance: Flood Risk and Coastal Change’ as having a high probability of flooding. The proposal is for Five Estuaries offshore wind farm which is classified as a ‘Essential Infrastructure’, as defined in Annex 3:Flood Vulnerability classification of the Planning Practice Guidance. Therefore, to comply with national policy the application is required to pass the Sequential and be supported by a site specific Flood Risk Assessment (FRA). 4.3 The key points to note from the submitted FRA’s, referenced Volume 5, 3.1. Export cable corridor and Volume 5, 3.2 Onshore substation dated March 2024, are: • Parts of the site outline lie within the flood extent for a 1% (1 in 100) and 0.5% (1 in 200) annual probability event, including an allowance for climate change. • The applicant has sequentially sited the onshore substation entirely within Flood Zone 1. • Cable corridor will use trenchless construction techniques and once constructed there will be no surface features therefore will not increase flood risk however these cross multiple main rivers (Holland Brook, Kirby Brook, Tendring Brook, Beaumont cut and Tenpenny Brook) and will require Environmental Permit for Flood Risk Activities. Applications should also include any temporary/enabling work. • Compensatory storage is not required. • An Evacuation plan has not been submitted Other Sources of Flooding 4.4 In addition to the above flood risk, the site may be within an area at risk of flooding from surface water, reservoirs, sewer and/or groundwater. We have not considered these risks in any detail as they are not within our remit, but these risks should be considered fully by the relevant authorities before determining the application. Safety of Inhabitants – Emergency Flood Plan 4.5 The Environment Agency does not normally comment on or approve the adequacy of flood emergency response procedures accompanying development proposals, as we do not carry out these roles during a flood. We note that a plan has not been submitted, the Local Authorities may wish for their emergency planners and the emergency services to determine whether the proposals are safe in accordance with paragraph 173 of the NPPF and the guiding principles of the PPG. Environmental Permit for Flood Risk Activities 4.6 We note that the applicant is seeking to dis-apply environmental permits for flood risk activities. We will review the Protective Provisions and provide further comments as part of our Written Representation. An environmental permit for flood risk activities may be required for work in, under, over or within 8 metres (m) from a fluvial main river and from any flood defence structure or culvert or 16m from a tidal main river and from any flood defence structure or culvert.