Thanet Extension Offshore Wind Farm

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.

Thanet Extension Offshore Wind Farm

Received 12 September 2018
From Environment Agency on behalf of Environment Agency


The Infrastructure Planning Commission
Temple Quay House
Dear Sir/Madam

Application for a Development Consent Order - Thanet Extension Offshore Wind Farm

Having reviewed the application details for the above proposal we have the following relevant representation to make:

The Role of the Environment Agency
The Environment Agency has 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 and 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.

Outstanding information and issues of concern
Our relevant representation outlines where further work, clarification or mitigation is required to ensure that the proposal has no detrimental impact on the environment. Our comments –in relation to the impact on the Pegwell Bay saltmarsh and the Water Framework Directive assessment- raise concerns which we believe need to be addressed prior to a development consent order being granted.

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 above, and to ensure the best environmental outcome for this project.

Yours faithfully

Ms Jennifer Wilson
Planning Specialist

Direct dial 0208 474 6711
Direct e-mail [email protected]

Relevant Representations
On behalf of the Environment Agency

Environmental Statement Volume 2
Chapter 5: Benthic Subtidal and Intertidal Ecology

Saltmarshes are ecological important features for birds, fish and invertebrates, they are an important source of carbon to adjacent features such as mudflats and act as natural sea defences. The importance of Pegwell bay saltmarsh is discussed in more detail later in this response.

Table 5.9: Valued Ecological Receptors (VERs) within the Thanet Extension benthic ecology study area, their conservation status and importance

Comment: Unfortunately this table does not include saltmarsh present, which is a valued ecological receptor and has high conservation importance.

Table 5.10: Maximum design scenario assessed
Permanent loss of saltmarsh from an extension of the seawall seawards of a curved structure (155 x 18.5 m) for worst-case this will result in loss of 0.0014 km2 loss of saltmarsh habitat (which represents 0.13% of the saltmarsh present within the SAC – noting that this is the smallest designated site at Pegwell Bay and therefore representing the worst-case in terms of percentage habitat lost).

Comment: This is the narrowest section of saltmarsh to the north of the River Stour but any seaward extension at this point (as detailed in report being 18.5m seaward) will effectively bisect the continuous saltmarsh habitats that is present to the north and south of the country park fragmenting the saltmarsh habitats. There is no evidence that new saltmarsh will establish itself in front of this proposed seawall extension and it is more likely this structure will cause local erosion of saltmarsh immediately adjacent to it.

5.10.25 The magnitude of the impact (taking the embedded mitigation into consideration) has been assessed as Low, with the sensitivity of the saltmarsh being assessed as Medium. Therefore, the significance of effects from direct disturbance occurring as a result of the export cable installation activities is Minor adverse, which is not significant in EIA terms.

Comment: This statement only applies to temporary disturbance to the saltmarsh and is not applicable to permanent saltmarsh loss and bisection of saltmarsh habitat as detailed previously. Therefore we disagree with this statement.

5.11.19 The total maximum area of saltmarsh loss due to the sea wall works described in Table 5.10 is predicted to be 0.0014 km2. This equates to 0.13% of the saltmarsh habitat within the Thanet Coast and Sandwich Bay SAC (it should be noted that the saltmarsh is not a feature of this SAC). Given that this habitat is widespread and common throughout the area, this represents a very small footprint compared to the overall extent. The area of permanent loss of saltmarsh has a maximum extent of 18.5 m from the existing sea wall. The saltmarsh in this area of Pegwell Bay extends between approximately 45 – 110 m from the existing sea wall out to a maximum width of 155 m; consequently, the extension to the sea wall will not give rise to any separation of areas of the saltmarsh habitat. While the impacts will be permanent, the impacts will be localised and will not split the habitat; therefore, the magnitude of the impact is assessed as low.

Comment: We disagree with their conclusions because this location is the narrowest section of saltmarsh, this will cause significant bisection of the habitat and no supporting evidence is provided to show that further erosion by the addition of a protruding section of new seawall will not cause local erosion of existing saltmarsh adjacent to this landfall location.

5.11.21 While the saltmarsh is a feature of the SSSI, it is not a feature of a Natura 2000 site. The proposed landfall area is an area that is considered to be generally lower value saltmarsh as a result of the areas of saltmarsh being elevated above the wider area such that it is not regularly inundated by tidal water and therefore being dominated by Spartina and grasses. It is therefore considered to be lower quality when compared to other areas of the saltmarsh within Pegwell Bay. The low quality and low potential to improve, combined with the status of the designation, means that the sensitivity of the habitat to the permanent loss of this area of saltmarsh is assessed as medium.

Comment: From personal observation, this area does get inundated on high tides. Accordingly, we do not where this evidence for these statements come from. We would like to know if there is there a typographic survey and a Pegwell Bay wide saltmarsh quality assessment and would like to have the opportunity to comment on it.

Saltmarsh Mitigation, Reinstatement and Monitoring Plan
4.1.2. Saltmarsh is common throughout Pegwell Bay and is present throughout the proposed cable installation site. The quality of the saltmarsh increases to the south of the Stour, with patchier, less diverse assemblages being found to the north of the Stour. Pegwell Bay saltmarsh is not a recognised feature of the Sandwich Bay SAC. However, it is included as a supporting habitat for roosting and feeding activity for the designated bird species golden plover and turnstone within the Thanet Coast and Sandwich Bay SPA/ RAMSAR and is also a feature of the Sandwich Bay to Hacklinge Marshes SSSI.

Comment: Whilst Saltmarsh is present within Pegwell Bay, it only occupies a relatively small area of the total intertidal area and is concentrated around the river mouth. This statement implies that is a common feature and is of less importance. Regionally this area of saltmarsh is extremely important as the map below shows:

Unlike the Thames estuary/southern North Sea, the Eastern Channel waters have very little saltmarsh available to support the huge range of species that depend on this habitat. Numerous studies (e.g. S.Colclough,et al 1995, Bell F.W. 1997, Boesch D. & Turner R. 1984) have shown the ecological and economic value of saltmarsh in particular relation to commercial and recreational fisheries. Surveys undertaken by the Environment Agency and the Kent and Essex Inshore Fisheries and Conservation Authority (IFCA) in Pegwell Bay show how even single saltmarsh creeks can provide shelter and feeding grounds for a wide range of marine fish species e.g. a survey on 11th August 2010 found these species around a single saltmarsh creek at Pegwell Bay.

a) River in front of Saltmarsh

Common name Number Range in mm (Fork length)
Flounder 2 41 - 59
Sprat 24 45 - 63
Bass 40 12 - 20
Sand/Common Goby 100 <20
Crangon 1

b) Shore and saltmarsh

Common name Number Range in mm (Fork length)
Golden-grey mullet 2 94
Sprat 5 36-39
Sand smelt 4 50-53

c) Upper saltmarsh creek

Common name Number Range in mm (Fork length)
Herring spp * 4 20-23
Sprat 17 40 - 52
Bass 2 37-38
Sand/Common Goby 30 <20
* To be identified

d) Lower saltmarsh creek

Common name Number Range in mm (Fork length)
Mullet spp c.200 25-30
Bass c. 60 18-24
3-spined stickleback 1 n/a
Sand/Common Goby 100 <20

The presence of large numbers of juvenile Bass, Mullet, Herring, Sprat and lesser species show that if these results are scaled up the value to fisheries alone in Pegwell Bay is highly significant and this is one of only two areas of permanent saltmarsh in the Eastern Channel waters between East Sussex and Thanet.

Environment Agency’s view of landfall options:
With regard to the landfall options, we consider that Option 1 is the less damaging to the saltmarsh habitats and should be given highest priority.

Option 3 is the second least damaging but has a larger impact upon the saltmarsh than Option 1.These impacts were assessed to be temporary and we agree with this assessment provided careful mitigation measures are taken during the construction phase and baseline topographic heights are reinstated.

Option 2 is potentially the most damaging of all and could result in permanent fragmentation of a regionally important habitat. We object to this option.

There does not appear to be a clear evidence pathway that fully explains why alternative landfall sites were discounted, what the constraints were and why options such as running up the river Stour channel were not assessed other than potential movement of the river channel (this point needs to be explained why it is not feasible in the projected life of the wind farm infrastructure – i.e. is there evidence that the river channel has moved significantly over last 25 years?).

Bell F.W. (1997) The economic valuation of saltwater marsh supporting marine recreational fishing in the south eastern United States. Ecological Economics 21, 243–254. (PDF copy attached)

Boesch D. & Turner R. (1984) Dependence of fishery species on saltmarshes: the role of food and refuge. Estuaries 7, 460–468. (PDF copy attached)

Colclough S., Fonseca, L, Astley T., Thomas, K. & Watts W. (2005) Fish utilisation of managed realignments Fisheries Management and Ecology, 2005, 12, 351–360 (PDF copy attached).

Environmental Statement Volume 4
Annex 3-1: Water Framework Directive Assessment

The Water Framework Directive (WFD) and its daughter directive the Environmental Quality Standards Directive (EQSD) sets forth the chemical concentration limits for controlled substances in the water of EU designated coastal and transitional waterbodies, and provides a classification method to describe the chemical and ecological status of each waterbody, using a variety of classification tools of which water quality is simply one element. The aim is to prevent deterioration of status and manage improvements towards good status. Activities requiring a marine licence must be assessed for the potential impacts upon the status of the waterbody and their potential to prevent the achievement of good status (or other alternative objectives as set out in the river basin management plan) for that waterbody in the future. We publish guidance on how to conduct an assessment for WFD risk,

This guidance includes how to scope in/or out any activity from a further “impact assessment” stage, by considering each of the elements contributing towards WFD status. Water quality elements are considered within the water quality section of the scoping form , which asks the applicant relevant questions, the answers leading the applicant to either scope out the activity form further assessment or to conduct a full impact assessment, where relevant evidence and arguments must be presented to justify acceptable risk levels for WFD compliance . In the case of water quality there are clearly defined concentration limits for whole suites of chemicals which must not be exceeded, and are necessarily numerical and complex in order to justify whether sufficient dilution of contaminant chemicals is available in cases where sediment may be disturbed which contains any of the chemicals for which standards exist in WFD and EQSD. Bathing and shellfish waters are also included as protected elements of WFD water quality, and here the triggers for compliance /non-compliance relate to bacterial concentrations in water and in shellfish flesh respectively. There being no accepted methods to characterise the bacterial levels in sediments, it can be complex and expensive to attempt to predict the transfer of sediment bacteria into the water column (where it might affect bathing water compliance) or from the water column to shellfish flesh, and often it is more sensible to be precautionary about timing the activity to avoid the bathing season altogether (ensuring certainty that bathing waters classification cannot be affected) than take risks which are assumed to be low but are, in reality, unknown due to uncertainty in sediment bacterial concentrations.

The water quality elements of the WFD Assessment, which the applicant claims to have undertaken using the Environment Agency’s own (Clearing the Waters for All) published guidance for conducting such an assessment, lack any rigorous numerical justification of WFD compliance, and do not provide any justification for “scoping out “water quality from a more detailed impact assessment. Had the applicant followed our guidance correctly, then they would have identified a potential risk from disturbing sediments which contain “substances on the EQSD list AND substances on the CEFAS list at levels above CEFAS Action level 1”-and this would be an automatic trigger NOT to scope out water quality, but to proceed to “impact assessment” stage- where we would expect more detailed and numerical consideration of the potential impacts on water quality.

We would expect consideration of the existing background concentrations of these chemicals in the waterbody, and a numerical calculation with any assumptions justified, of the load transfer of each chemical from sediment to water, to calculate what uplift, if any , in the ambient water column concentration would occur at the site where the disturbance of sediment is taking place, how long such uplifts will last and what area of waterbody, if any, may suffer uplifts in concentration that would exceed the EQS limits for the waterbody. There being two standards for some substances (Annual Average, and Maximum Allowable Concentration) for which Environmental Quality Standards (concentration based limits for water) exist, both need consideration where both have limits. No figure for dilution capacity in the receiving water body has been provided, so the conclusions that the activity remains WFD compliant for water chemistry remains opaque.

Similarly the conclusions regarding the activity being benign for bathing water quality are largely based on drawing parallels with earlier activity, which is no guarantor of future bathing water quality, as the bacterial levels in the sediments were not tested either then or now, and the prediction of compliance is based entirely on the assumption that there will be adequate dilution of any mobilised load before it reaches the bathing water. Again no dilution factor is actually provided so this is speculative, and as the initial load (bacterial concentration in sediment) is unknown anyway, there may or may not be sufficient dilution. As the actual risk is unknown, it would be safer to have a requirement within the Development Consent Order which allows for a temporary cessation of works should the bathing waters be seen to deteriorate when work is in progress. This would probably be a more proportionate and acceptable option than to require that the sediment disturbing operations are limited to occur outside the bathing waters monitoring period – which is the only certain means of ensuring the activity cannot impact upon bathing water quality if the sediments do contain significant bacterial loads at the time of disturbing them.

This is not to say that we believe the activity will result in a WFD deterioration, the general points made about high (but unspecified) levels of dilution may well suggest compliance, but we consider that the current assessment does not provide the detailed “impact assessment” arguments of a more technical and numerical nature that we would consider a proper part of the WFD water quality assessment. Arguments for compliance need to be supported by evidence.

Environmental Statement Volume 5
Annex 6-1: Phase 1 Geo-environmental Desk Study
The phase 1 geo-environmental report submitted with the application states:

This Phase 1 report constitutes a robust characterisation of the receiving environment to support the EIA. The site reconnaissance and desk-based assessment has identified a number of potential contaminant linkages and geo-environmental constraints associated with the proposed onshore development. In order to gain a more detailed understanding of these constraints, further SI and assessment would be required post-consent as part of the detailed design process, prior to construction.

As additional site investigation works are required to assess the on-shore impacts as part of the detailed design process we request these elements are included in any consent requirements. The wording in the draft DCO appears to cover these issues adequately and further investigation and relevant actions should follow CLR11 protocols to comply with these requirements.

The CLAIRE Definition of Waste: Development Industry Code of Practice (version 2) provides operators with a framework for determining whether or not excavated material arising from site during remediation and/or land development works are waste or have ceased to be waste. Under the Code of Practice:

• excavated materials that are recovered via a treatment operation can be re-used on-site providing they are treated to a standard such that they fit for purpose and unlikely to cause pollution
• treated materials can be transferred between sites as part of a hub and cluster project formally agreed with the Environment Agency.
• some naturally occurring clean material can be transferred directly between sites.

Developers should ensure that all contaminated materials are adequately characterised both chemically and physically, and that the permitting status of any proposed on site operations are clear. If in doubt, the Environment Agency should be contacted for advice at an early stage to avoid any delays.

• The Environment Agency recommends that developers should refer to:
• the Position statement on the Definition of Waste: Development Industry Code of Practice and;
• The Environmental regulations page on GOV.UK

Any re-use of excavated materials not undertaken formally using the CLAIRE DoWCoP would require an environmental permit for deposit, unless materials are solely aggregates from virgin sources, or from a fully compliant Quality Protocol aggregates supplier. Any deposit of materials outside of these scenarios could be subject to enforcement actions and/or landfill tax liabilities.

Environmental Statement Volume 5
Annex 6.2: Flood Risk Assessment
Provided the recommendations and guidance provided within the submitted Flood Risk Assessment are followed, we have no flood risk related concerns or requirements related to the development proposed.

As per our previous response, we would encourage further engagement with us once more is known about the chosen option for the Transition Joint Bay (TJBs) (i.e. the general areas where the cable comes ashore and the associated transition arrangements).

We would also recommend that we are contacted to discuss the means of crossing the Minster Stream, along with any other works within 16m of the tidal River Stour (or within 8m of the Minster Stream). Any such works will require a Flood Risk Activity Permit prior to the commencement of any construction within the byelaw margins. This is of particular concern owing to the outlined proposals for the required reconstruction of the existing culvert.

Draft Development Consent Order (DCO)
Due to our concerns in relation to the proposed landfall options - the potential significant the loss of saltmarsh, as well as the additional clarification needed with regards to the Water Framework Directive - we consider that the draft DCO does not adequately deal with these issues.

The current draft DCO looks at addressing all the landfall options by considering the worst case scenario (Option 2) which we have previously advised 2 should not be an option in our opinion. We do not provide detailed comments on the draft DCO at this stage as we consider there are still fundamental issues that need to be overcome, specifically a decision on which landfall option the applicant intends to progress with.

Please see attached.

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