Representation by Environment Agency (Environment Agency)
- Date submitted
- 19 July 2023
- Submitted by
- Other statutory consultees
Please find enclosed the Relevant Representation on behalf of the Environment Agency in relation to the above application for a Development Consent Order (DCO). The Environment Agency’s Role We are a statutory consultee on all applications for DCO. We have a responsibility for protecting and improving the environment, as well as contributing to sustainable development. We have three main roles: 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. 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 an integrated way. We provide a vital incident response capability. 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. Relevant Representation Overview We have reviewed the submitted documents and have provided below a summary of matters where we consider that further clarification is required to ensure that the proposal has no detrimental impact on the environment. These matters include flood risk, groundwater protection, biodiversity, water resources and environmental permitting. We reserve our right to add to or amend the matters set out in this Relevant Representation and will update the Examining Authority on any amendments to our position at the appropriate point during the examination of the DCO. Please do not hesitate to contact me if you require any further information. Yours faithfully Neville Benn Planning Specialist Sustainable Places Mobile: [Redacted] Direct e-mail [Redacted]@environment-agency.gov.uk Flood Risk Please note that the text included in Appendix 20.5 and 20.6 of the Environmental Statement appears to have been mixed up. The submitted Flood Risk Assessment (Appendix 20.1 of the Environmental Statement) refers to fluvial modelling presented in Appendix 20.5 (entitled Fluvial Model Report). However, the Fluvial Model Report provides details of the 3D velocity mixing model, while Appendix 20.6 (entitled 3D Velocity Mixing Model) provides details of the fluvial modelling undertaken to inform the Flood Risk Assessment (FRA). We have therefore referred to Appendix 20.6 instead of Appendix 20.5 in our comments below. Issue 1.1 Potential increase in flood risk to third party land and properties The Fluvial Model Report included in Appendix 20.6 of the Environmental Statement presents the results of hydraulic modelling undertaken to assess the impact of the proposed outfall discharge into the River Cam on local flood levels in the River Cam. This modelling indicates that there will be increases in flood levels up to 22mm downstream of the outfall during smaller magnitude flood events. The FRA included in Appendix 20.1 of the Environmental Statement has not assessed the potential impact of this increase in flood levels on local flood risk, including any receptors (i.e. potential increase in flood extents and depths). Adequate mitigation needs to be provided to prevent any increase in flood risk elsewhere for all flood events, up to and including the ‘design flood’ (i.e. the 1% annual probability event, including an appropriate allowance for climate change). Solution The FRA needs to clearly show the locations of the areas of land where an increase in flood depths is shown in the modelling during different flood events. Please note that the scheme would be considered unacceptable if it introduces any new areas of land or property to flood risk as this would be contrary to the NPPF (paragraph 164), which requires an FRA to demonstrate there will be no increase in flood risk elsewhere. If the modelling shows any increase in flood depths in areas where properties are already at risk of flooding, the FRA needs to clearly demonstrate how any increase in flood risk will be mitigated. Any increase in flood risk to properties would be unacceptable; where possible, a reduction in flood risk should be sought, in line with the second part of the Exception Test. Any increase in flood risk to third party land should also be mitigated. In exceptional circumstances, where an increase in flood risk to small areas of land already at risk cannot be mitigated, clear reasons for this would need to be provided. The relevant landowners would need to be fully informed of the increase in flood risk to their land in terms of increased frequency, depths, extent and duration of flooding. Evidence that the relevant landowners accept the predicted increase in flood risk to their land would also need to be provided in writing. Advice for the Applicant Please note that a new model of the River Cam will be available in the near future. The outputs of this modelling may need to be taken into consideration when assessing the impact of the predicted increase in flood levels on flood risk within third party land. In particular, the hydrology has been updated and the Standard of Protection of some of the flood defences along the River Cam may have reduced. Issue 1.2 Insufficient information provided to allow us to determine whether the hydraulic model is fit for purpose Hydraulic modelling has been undertaken as part of the FRA (Appendix 20.1 of the Environmental Statement) to assess the impact of the proposed discharge into the River Cam on local flood risk. As the model files have only recently been provided to us for review, we have not had sufficient time to review the model and determine whether it is acceptable for the purpose of this DCO. Solution If any issues with the model are identified during our review, these will need to be addressed before we can accept the results presented in the FRA. Groundwater Protection and Contamination Issue 1.3 – Insufficient preliminary assessment and analysis. There is further clarification, justification and information that needs to be supplied to demonstrate that there will be no detrimental impact on groundwater. Appendix 14.1: Preliminary Risk Assessment, 5.4.14.1, April 2023 We are generally satisfied with this report and in agreement with the conclusions and recommendations. However, it is not clear why the conceptual site model and preliminary qualitative risk assessment (PRA) make no reference to the Waterbeach Water Recycling Centre (WRC). In addition, previous reports are referenced but not provided, and the ENVIROCHECK report covers only part of the area within the Scheme Order Limits. Appendix 14.3 Geoenvironmental Results proposed WWTP, 5.4.14.3, April 2023 We are unable to make sense of the soil analysis results. In addition, accreditation information has not been supplied and there is therefore a potential question mark over the robustness of the results. The measured concentrations of contaminants within leachate samples are unlikely to pose an unacceptable risk to controlled waters. However, if the U in the accreditation column indicates an unaccredited method, then there is a potential question mark about the robustness of the results. The groundwater analysis, taken overall, are not indicative of widespread gross groundwater contamination. However, no accreditation information has been supplied, and the uncertainty about the magnitudes of impacts to groundwater from Cr III should be addressed. In addition, there was no testing for MTBE or pesticides even those were identified as potential contaminants within the PRA. Appendix 14.4 Geoenvironmental Results Waterbeach, 5.4.14.4, April 2023 The concentrations of contaminants measured within soil samples are unlikely to pose an unacceptable risk to controlled waters. However, there was no testing for ammonium or pesticides even though these were identified as potential contaminants within the PRA, and no testing was targeted to the Waterbeach WRC. It appears that there was no testing of groundwater for this part of the scheme. We do not regard this as acceptable. ES Chapter 14: Land quality, 5.2.14, April 2023 It is concluded in this report that the impacts of contamination to land quality would not be significant. However, key items of supporting information are missing, including details of sampling methodologies, logs for exploratory holes, laboratory certificates, details of groundwater level monitoring, contextual information relating the locations of sampling points to specific sources identified with the PRA, and copies of previous investigation reports as referenced within the document. In addition, as noted in respect of the Geoenvironmental reports, we have concerns about the accreditation of laboratory methods, the lack of testing for some potential contaminants as identified within the PRA, and the lack of groundwater testing for the Waterbeach pipeline route. ES Volume 4 Chapter 14 Appendix 14.2 Contaminated Land Risk Assessments, 5.4.14.2, April 2023 See comments provided for the Geoenvironmental and the Land Quality reports. Appendix 20.8: Update to Contaminant Transport Model, 5.4.20.8, April 2023 We have not had the opportunity to review the digital CONSIM models for the contaminant transport modelling assessment. However, from the information presented in this report, the set-up and parameterisation of these models appears to be satisfactory, and the conclusions are supported by the results of the modelling and defensible. Appendix 20.4 Dewatering Pump Test Technical Note, 5.4.20.4, April 2023 From the information presented in this report, the methodology and design of the pumping tests appears to be robust. The ranges in aquifer properties derived through analysis of the results are defensible, as are the conclusions reached regarding the likely magnitudes of construction dewatering impacts. ES Volume 4 Chapter 20 Appendix 20.12 Drainage Strategy, 4.20.12, April 2023 We understand from this report that the surface water drainage strategy for the proposed WWTW will not rely upon the use of infiltration Sustainable Drainage Systems (SUDs). The use of infiltration SUDs would only be acceptable where it can be demonstrated that they will not pose a risk to the wider water environment. ES Volume 4 Chapter 20 Appendix 20.9 HIA (Site Selection Stage), 5.4.20.9, April 2023 We previously commented on this report under a pre-application consultation and have not re-visited it. We note that to an extent it is outdated as relevant supplementary or amended information has been made available e.g., via the dewatering pump test technical note, the contaminant transport model document and the water resources document. Environmental Statement Chapter 20: Water Resources, 5.2.20, April 2023 We are in general agreement with the conclusions of this report. However, we expect further discussions with the applicant regarding requirements for groundwater monitoring. Proposals for such monitoring are outlined in Sections 4.1.278 to 4.1.280 and 40.2.140 to 4.2.144. However, a borehole location plan has not been provided and should be supplied so that we can further evaluate these specific proposals. In addition, we are concerned that groundwater monitoring for the new WWTW only is proposed. On a precautionary basis would like to see operational phase groundwater quality monitoring for the wider scheme so that any unacceptable impacts to can be detected and appropriate mitigation measures implemented. We are particularly concerned about potential leakages from infrastructure that will be used for underground or sub-water table transmission of pollutants. As per 4.1.280 we expect the applicant to engage with us in order to reach agreement requiring the scope and duration of groundwater monitoring. Water Resources Water resources has become a significant (strategic) issue recently due to our concerns about groundwater abstraction having an impact on the ecology of waterbodies in the Cambridge area and beyond. Developments located in this area are also located within an area serious water stress (as identified in our report Water Stressed Areas - final classification: https://www.gov.uk/government/publications/water-stressed-areas-2021-classification). We have evidence that indicates abstraction from groundwater to meet current needs of the population is already causing ecological damage to some Water Framework Directive (WFD) designated water bodies including chalk streams (where applicable) or there is a risk of causing deterioration to the ecology if groundwater abstraction increases. The proposed new facility is replacing the existing works so no additional demand to the water supply will be made. We are expecting water efficiency standards and water consumption estimates to be provided to us. The applicant should be made aware that an abstraction licence will be required for any dewatering that takes place during construction. Refer to our website on guidance for applying for an abstraction licence. Check if you need a licence to abstract water - GOV.UK (www.gov.uk) Dewatering the proposed abstraction may lower groundwater levels locally and may derogate nearby domestic and licensed groundwater sources. The de-watering should not detrimentally affect local water features (including streams, ponds, lakes, ditches, or drains) this includes both licensed and unlicensed abstractions. We note that a consent to derogate agreement will be sought to offer protection to private water supply user. We would recommend monitoring is undertaken during the de-watering phase and mitigation identified to provide an alternative source of water should their water supply be impacted. It is also noted that there is the potential to impact on water levels at Wilbraham Fen SSSI during the de-watering phase, which is a partial groundwater fed site. Again monitoring should be established and a review undertaken of level of risk and recovery times / and any mitigation options. Biodiversity and Ecology We are content with the information that has been provided and the appropriate mitigation measures being proposed ahead of/during construction. We are pleased to see the relevant licences have been applied for regarding water vole, badger and bats. We have some concerns regarding potential scouring at the outfall and we will need to be kept informed of the monitoring. We would recommend a reed bed system being implemented at the exit of the outfall, before reaching the watercourse. This would also be beneficial to keeping a steady discharge flow and keeping the water clean. Biodiversity Net Gain The statutory requirements for NSIPs to provide 10% BNG will become a legal requirement in 2025. The applicant is committed to 20% Biodiversity Net Gain (BNG) overall, with no ‘trading down’ in habitat condition or quality. We fully support this ambition. River units The applicant has recognised that delivery of river units on site is not possible due to the constraints on the river Cam at this location (river users, angling etc). However, they propose to purchase river units offsite as/when they become available. Is there some legal mechanism to ensure that this does actually occur? Ditches Creating a new wetted ditch area to compensate for the loss of ditches in the site, and also to contribute to the water vole mitigation/ compensatory habitat. There is relatively recent clarification around the requirement for BNG and mitigation/ compensation. Environmental Permitting Discharge Permit Appendix 20.11: Milton Water Recycling Centre Discharge Consent: Water Quality and Ecological Assessment, Revision No.01, April 2023 This report contains water quality modelling information for suspended solids and phosphorus limits. This modelling was undertaken following our response to an Environmental Permitting pre-permitting application consultation, Letter ref: ASCNF/1033/V004, dated 09/10/2020. Anglian Water have applied for an Environmental Permit for the proposed new site (received 09/09/2022). To avoid prejudicing the determination of the Environmental Permit application we will not be making comments on the modelling approach or results provided within our response to this DCO application. If they have not already done so, the applicant may pass the modelling detail and results to us for consideration as part of the Environmental Permit application process. Installations Permit - Sludge Treatment Centre (STC) The proposed anaerobic digestion plant and CHP will require an environmental permit under Schedule 1 of the Environmental Permitting Regulations 2010. We will be including the following key areas of potential harm when making an assessment for the Permit: • Techniques for pollution control including in process controls, emission control, management, waste feedstock and digestate, energy, accidents, noise and monitoring. • Emission benchmarks for combustion products, temperature and pH. • Air quality impact assessment, including odour and Habitats Regulations Assessment. Decommissioning Detailed advice has already been provided for the outline decommissioning plan of the current Sludge Treatment Centre. We are satisfied with the draft decommissioning plan (Appendix 2.3: Outline Decommissioning A Plan) that it sets out the process and follows the guidance that: • A site condition report is required at the surrender stage in accordance with our guidance. The information provided in the outline plan covers what we would expect to see in terms of returning the site to a satisfactory condition. The applicant has indicated that they will be undertaking sampling to demonstrate that they have left the site in a similar state to when they started operations. • The removal or the flushing out of pipelines and vessels where appropriate and their complete emptying of any potentially harmful contents will be undertaken and covers what we would expect to see. • Drawings showing all the underground pipes and vessels that is available will be presented in a full decommissioning plan. • Sets out methods and resources for clearing all tanks / lagoons on site, which is what we would expect. • An asbestos survey has been completed. It hasn’t been expressly stated that this will be removed. This will need to be detailed in the final decommissioning plan. • The plan covers what we would expect to see in terms of methods of dismantling all equipment in a way that will protect the environment. • The report indicates that the plan will follow our guidance on decommissioning and would follow our guidance RGN 9 and H5 guidance for surrender of the permit. • The outline plan demonstrates that once activities have ceased, to avoid any pollution risk and to return the site to a satisfactory state (including, where appropriate, those covering the design and construction of the plant. • Clearing deposited residues, waste and any contamination resulting from the waste treatment activities. • The plan indicates that clearing deposited residues, waste and any contamination resulting from the waste treatment activities will be undertaken. • The plan indicates that de-commissioning of some plant and equipment, for example those with potentially explosive atmospheres present, is a specialist activity. That there must be a written procedures in place to support the safe removal or closure of plant on site. That equipment is taken out of use is decontaminated and removed from the site.