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Environmental Statement for Port of Southampton: Berth 201/202 Works updated by Further Information

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18. Cumulative and In-Combination Effects

18.1 The cumulative and/or in-combination effects of the proposed Berth 201/202 works have been assessed with respect to other relevant plans or projects that are at various points in the planning and consenting domain. In respect of marine related effects where the designs for the relevant identified projects these schemes are available, they have been included in the numerical model in order to ascertain the detailed morphological effects on the hydrodynamic and sedimentation regimes. Appendix C contains a more detailed commentary on the modelling that was undertaken to inform this assessment. The in-combination effects of construction activities (i.e. noise and water quality impacts) on nature conservation features and the cumulative impact of the disposal of dredge arisings from different plans or projects at the Nab Deposit Ground have also been assessed. In addition, if the Berth 201/202 redevelopment were to occur at the same time as ABP’s Southampton Approach Channel Dredge, there is the potential for cumulative environmental noise impacts on residents at Admiralty Quay.

18.2 The assessments of cumulative and/or in-combination effects are legally separate

requirements, although they rely on similar source data.

Cumulative Effects 18.3 Cumulative effects, which need to be addressed under the Marine Works EIA Regulations 2007,

refer to occasions where another project could have an impact via the same pathway (e.g. if both proposals altered tidal heights or caused disturbance to birds) and could, therefore, result in a change that is of greater or lesser significance than the effects of this proposal in isolation.

In-Combination Effects

18.4 Under the Conservation of Habitats and Species Regulations 2010 Conservation (Natural

Habitats & c.) Regulations 1994 (‘Habitats Regulations’), it is also necessary to consider the in-combination effects of development proposals on European Sites. These refer to effects, which may or may not interact with each other, but which could affect the same receptor or interest feature (i.e. a habitat or species for which a European Site is designated). For instance, bird species could be affected by disturbance from one proposal and habitat loss by another.

Relevant Plans and Projects

18.5 There are a number of plans and projects that have been identified through extensive

consultation with a range of stakeholders as potentially having cumulative and/or in-combination effects with the Berth 201/202 works. In producing the Further Information, additional projects to be taken account of were identified in correspondence with Southampton City Council. Whilst it is a minor project, the proposed dredge to widen berths 204/5 has been considered and documented given its proximity to berths 201 and 202. Further details for each of the developments and their current position in the planning process are provided in Table 18.1.


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Table 18.1 Summary of plans and projects in the study area

Plan or Project Description Stage in Planning Process (Pre-Feasibility/Feasibility/

Scoping/EIA) Construction Timetable

Southampton Approach Channel Dredge

ABP propose to improve the vessel accessibility to the Port of Southampton by deepening and widening the navigation channel at various locations through Southampton Water and the Solent. This proposal is included in the cumulative and in-combination hydrodynamic and sedimentation modelling scenario. The cumulative and/or in-combination impacts resulting from the possible disposal of arisings at the Nab Deposit Ground have also been assessed.

EIA Stage Applications submitted and being considered by the MMO

Works anticipated to commence in 2012 towards the end of 2009 or early 2010, pending consent of planning application and associated approvals.

Portsmouth Harbour Approach Dredge

There is a requirement for Her Majesty’s Naval Base (HMNB) Portsmouth to accommodate larger vessels than present at Portsmouth. This will require navigational improvements including channel deepening, realignment, widening and disposal of material at the Nab Deposit Ground. In addition to the navigation channel, deepening of vessel berths could also be required. The details available of the updated scheme for this development are those currently being proposed in the Scoping Report, which has now been submitted for consideration by the regulators and, therefore, the potential cumulative and/or in-combination effects have been assessed based on the design outlined therein. ABPmer undertook numerical modelling studies of the proposed scheme on behalf of the EIA consultants, Royal Haskoning. Hydrodynamic and sediment modelling of the Berth 201/202 redevelopment alone created no impact in the area that would be impacted by the current Portsmouth Harbour Approach Dredge design. These results, in conjunction with the findings of the Portsmouth dredge modelling, suggest that no cumulative and/or in-combination effects will occur due to the indirect changes the hydrodynamic and sediment regime. However, the cumulative and/or in-combination impacts resulting from the possible disposal of arisings occurring at the same time at the Nab Deposit Ground have been assessed.

EIA stage. Dredge is currently proposed to commence in 2013/14 2011 at the earliest and last for around 15 months. The ultimate aim would be for the channel to be fully operational by 2014 in time for the carriers being built.

Woolston, Redevelopment of Vosper Thorneycroft Site

South East England Development Agency (SEEDA) acquired the Woolston Riverside development site from Vosper Thornycroft (UK) Ltd in March 2003 with the aim of regenerating the Brownfield site and transforming it into a catalyst for employment, housing, industry and marine-related businesses.

Hybrid planning application was submitted in 2005 and currently at the stage of finalising more detailed

Site works commenced 2008. The entire development should be complete within 8-10 years from start of


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Details of the latest available plan have been incorporated in the present modelling scenario.

applications with Southampton City Council.

construction on site if market conditions hold.

Marchwood Marine Park SEEDA is promoting a centre of excellence for marine related industries adjoining Southampton Water at Husbands Yard, Marchwood. The site covers 5.11ha and is situated immediately south of Marchwood Industrial Estate and to the north of Marchwood Military Port. The eastern part of the site (1.99ha), adjoining the Marchwood Military Port, falls within a blast zone within which no construction can take place. This part of the site would be suitable for storage and yard purposes only. The gross development area would, therefore, be 3.11ha. The latest available details have been represented within the current modelling.

Planning consent has been awarded.

Construction is planned to commence in 2009.

Cowes Breakwater and Marina Development

Cowes Harbour Commissioners and SEEDA are proposing to construct a breakwater off the entrance to the Medina Estuary and a marina within Cowes Harbour. At the same time, a secondary channel to the east of the harbour is proposed to allow small draught vessels to enter and leave the harbour away from the main deeper fairway channel. The proposal, which is referred to as the Cowes Outer Harbour Project contains the following elements: A new rubble mound outer breakwater to improve the wave climate within the harbour; Dredging of a new secondary navigational channel for traffic entering/leaving the harbour; Construction of a new marina with associated dredging to accommodate this development;

and Construction of associated shore side facilities within the marina. This proposal has been included in the current cumulative and in-combination modelling scenario.

EIA stage. Consents granted in 2010

Project at implementation stage Provisional construction timetable is to commence works October 2009, but will be dependent on achieving application consent.

Lymington Breakwater The proposal is to install two breakwaters within Lymington River. The saltmarsh that currently protects the harbour area is rapidly eroding and there are concerns that it will disappear completely unless action is taken. The project involves the creation of two low-lying rubble breakwaters outside the Lymington Harbour, one on the east and on the west side of the navigation channel. Each breakwater will be roughly 470m long and will stand roughly 1.5m above the saltmarsh. It is proposed to build the breakwater over a period of time in stages to reduce environmental and financial impact. In 2006, the Lymington Harbour Commissioners consulting engineers were working on a technical and geomorphological appraisal in order to identify a preferred design for the

EIA stage. Further environmental assessments are required prior to lodging the application for the various consents.

Unknown.


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breakwater. This study was completed towards the end of October 2006. The preferred design was assessed by consulting engineers as having a negligible impact on the hydrodynamics and geomorphology of the area. Furthermore, the modelling of the Berth 201/202 works alone created no effect in this area, indicating that there are no cumulative and/or in-combination effects between both projects.

Hythe Marine Park SEEDA’s primary aim is to ensure its long-term use for marine employment. The marine park currently provides some 22,000m2 of property set in approximately 4.9ha of land. The site is dominated by two large hangars, both with waterfront access, with one benefiting from a unique ship lifting facility, which is able to lift up to 950 tonnes. There are also workshops, paint shops and office accommodation as well as working berths, a pier, pontoons and barge platforms. Work has commenced on a package of site wide infrastructure improvements, which is enabling the sites use by marine companies. These include electrical upgrades, and a new vehicular access, and improved working berths and water access. A best representation of the marine side works for this project has been included in the cumulative and in-combination modelling.

Planning application was submitted to New Forest District Council (NFDC) in 2007. SEEDA is working with partners to take forward a planning application for new units over the coming months. Various consents granted

Upgrading of the buildings and waterside facilities is ongoing to enable occupation by marine businesses.

Capital Dredge at Berth 205 Berth needed to be deepened by 0.2m from existing depths of -13.8m Chart Datum (CD) to -14.0m CD. This small change has been incorporated into the modelling scenario.

Post application. Works completed ABP anticipate to undertake this capital dredge in 2009, subject to operational constraints and plant availability.

Lymington Wightlink Ferry Wightlink intend to upgrade their current ‘C’ class ships which run on their Lymington to Yarmouth service, with the new, larger ‘W’ class vessels. This scheme involves new piling and fender work at the terminal. There are no other direct physical effects on the marine environment. The main concerns relate to the operational effects of the ferries (ship wash). These effects will not interact with the Berth 201/202 redevelopment and, therefore, they have not been incorporated in the cumulative and/or in-combination modelling scenario.

Appropriate Assessment information document has been submitted and awaiting consent from MFA.

New ferries are currently undergoing sea trials and will be introduced once consent has been given.

Town Quay and Royal Pier/ Mayflower Park Development

Southampton City Council has identified the land at Royal Pier and Town Quay for a major mixed-use development that is intended to provide:

Pre-feasibility studies are being undertaken for the Mayflower Park Extension

Proposals on hold.


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Residential, local needs convenience retail, business use, leisure, tourism and cultural

development; A public waterfront destination of international quality; The provision of a water basin or basins that provides a visual and physical link between the

Old Town and the waterfront; Reclamation of land, if permissible, to provide an extension to Mayflower Park (approx.

2.6ha); Landmark buildings that define the site as an international gateway; Relocation and integration of all the existing passenger and vehicle ferries within Town Quay.

The development will need to fund this relocation; A public transport interchange between ferries and buses; and Improved pedestrian and cycle links to the city centre. Additional reclamation to include the whole area below high water mark within the site allocation could be considered (with the exception of a basin between the original lines of Royal Pier and the Town Quay) although this will be dependent on the final scale of mixed-use development. A representation of this scheme (i.e. the area of reclamation) and required dredging to move the existing ferry terminals has been inserted into the cumulative and in-combination modelling. It should be noted that this may be considerably different from any final design, should it take place.

scheme for Southampton City Council. Position likely to develop further in SCC’s emerging planning documents.

Seagrove Bay Breakwater Seagrove Bay is located on the Northeast coast of the Isle of Wight, approximately 3.5km from Ryde. In consultation with residents along the frontage, the Council developed proposals for a coastal protection scheme along this part of Seagrove Bay, to provide the necessary coastal protection for at least the next fifty years. The resolution of the model in this area and the location near to the shore do not allow this development to be modelled for the current assessment. Given that the breakwaters are already in place and the modelling of the Berth 201/202 works alone created no effect in this area, indicate that there will be no cumulative and/or in-combination effects between both projects.

Planning consent received. Breakwaters are now in place.


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Medina Barrage Early in 2007, the local authority was looking into building a barrage across the estuary at different locations. The plans were only an idea and needed to be reviewed to assess whether they are technically feasible. Other possibilities included a dam and generator or a simpler subsurface cill closer to Newport making the harbour more accessible to the public. This project is no longer being pursued due to the likely damage to the local environment (IOW Centre for Coastal Environment).

Pre-feasibility. Project no longer being pursued.

Solent Shoreline Management Plans (SMP)

The Solent is broken down into four key SMP’s, Western, Northern, Eastern and the Isle of Wight SMP. The general policy throughout the Solent at the moment is “Hold the Line”, with a few areas of managed retreat. Both Portsmouth (Eastern SMP) and the Isle of Wight are currently making amendments to their SMP’s although no major change in stance is expected. No known proposals for coastal defence or managed retreat are in the planning domain.

N/A N/A

Hamble Estuary Management Plans

The general principles behind the River Hamble’s EMP is to keep development (particularly on green field sites) and dredging to a minimum and support coastal defences which are consistent with the Habitats Directive, retaining the natural shoreline wherever possible. There are no planned major projects within the Hamble Estuary, other than the usual ongoing maintenance dredging of the marinas.

N/A N/A

Port Development on IoW The 2001 Isle of Wight Unitary Development plan, which has now been replaced by the IoW Core Strategy (2008), highlights the requirements for improving bulk-handling capabilities on the island although does not highlight any sites of interest. A third cross Solent ferry terminal is mentioned, with the location either being Ryde or Woodside. There are no known proposals currently in the planning domain.

N/A N/A

Capital dredge of berths 206 and 207

Removal of 21,190m³ of material to widen the existing berth pockets by 8m to 55m wide and deepen berth 206 by 1m to 14.6m CD. The scale of the works is such that this dredge would not affect the baseline and assessment work (including hydrodynamic and sediment modelling) that has been undertaken for the berths 201/2 proposal.

Consent granted by MMO August 2009.

Complete December 2010

Capital dredge of berths 204 and 205

Proposed minor dredge of approximately 6,000m³ to widen the berth pocket to 55m wide. This represents approximately 3%, by volume, of the proposed 201/2 capital dredge and less than 1.5% of the Port’s permitted annual maintenance dredge.

Screening request submitted to MMO.

N/A


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Helius Biomass Generating Station

This proposed Nationally Significant Infrastructure project seeks the development of a biomass fuelled power station and associated works within the Southampton Port Estate.

EIA Scoping / Consultation / Production

Construction stated to begin (subject to consent) in winter 2012 and continue for a 36 month period

Use of land for Port purposes with new internal access road arrangements within the vicinity of Dock Gate 20 within the Southampton Port Estate.

Planning permission 09/00106/FUL – Permission granted for the use of land for Port purposes with new internal access road arrangements (including lowering of land beneath the Dock Gate 20 access bridge), associated port security measures including control building with staff car parking, 28 new lighting columns and security fencing.

Consent granted 27 April 2009, but scheme still to be implemented.

Implementation to begin late 2011 / early 2012. Main elements to be constructed over a 6 month period.

Development of a new Council Depot and Household Waste Recycling Centre on land adjacent to First Avenue,

Planning permission 10/00385/R3CFL – Permission granted for the use of the site as a Council Depot and Household Waste Recycling Centre with a new vehicular entrance from First Avenue and exit onto Manor House Avenue. Depot facilities to include storage, parking, fleet workshop and associated facilities. Erection of a 3-storey building for office and staff facilities. (Application was amended to change the proposed vehicular access arrangements and omission of the previously proposed traffic signalised junction on First Avenue).

Consent granted 20 September 2010.

Construction underway and scheme nearing completion. SCC website indicates that scheme will be open in January 2012.

Redevelopment of part of the British American Tobacco Co Ltd site in Regents Park Road to provide a warehouse club.

Planning Application 10/01449/FUL – Permission sought for the redevelopment of part of the British American Tobacco Co Ltd site in Regents Park Road to provide a warehouse club (13,006 square metres gross external floorspace) including tyre installation, sales and associated facilities with vehicular access from Regents Park Road.

Conditionally approved Unknown

N/A - not applicable


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18.6 In summary, the plans and projects that are considered relevant to the proposed Berth 201/202 redevelopment and have been included in the cumulative and in-combination assessment are:

Southampton Approach Channel Dredge; Woolston, Redevelopment of Vosper Thorneycroft Site; Marchwood Marine Park; Cowes Breakwater and Marina Development; Hythe Marine Park; Capital Dredge at Berth 205; Town Quay and Royal Pier/Mayflower Park Development; and Portsmouth Harbour Approach Dredge; Capital dredge of berths 204 and 205; Helius Biomass Generating Station; Internal Port access road proposals; Council Depot / Recycling Centre; and Redevelopment of part of BAT site.

Impact Assessment

18.7 In respect of marine related effects, for each plan or project, the location relative to the

designated areas has been established, along with the nature and scale of the works. This information is used to identify direct and indirect cumulative and/or in-combination changes in the marine environment. These potential changes are then summarised and the combined impact of all relevant projects on the marine ecological systems are compared with the impact of the proposal alone. For other effects a similar approach has been adopted, i.e. the potential changes that could arise from the relevant projects are compared with the impact of the project alone. The impacts that may result in cumulative and/or in-combination effects that may result are summarised in Table 18.2.


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Table 18.2 Summary of cumulative and/or in-combination effects and assessment

Impact Summary of Predicted Cumulative and In-Combination Effects Cumulative and/or In-

Combination Assessment

Mitigation Residual Effect

Water levels The additional developments will cause high water levels up estuary of Mayflower Park to be increased on average by 3mm, but up to 1cm immediately adjacent to Mayflower Park. This will be in the opposite direction to the Berth 201/202 works alone, which predict a reduction in high water levels of up to 2mm in the vicinity of Berth 201/202. In this way, the negligible change to water levels resulting from the Berth 201/202 works will be ‘cancelled out’ if all the other developments were to take place. Within the area of the Western Docks and container terminal, low water levels will be increased marginally, predominantly due to changes brought about by the Southampton Approach Channel Dredge and Town Quay and Royal Pier/Mayflower Park Developments. The 1mm increase in low water levels predicted due to the Berth 201/202 redevelopment alone will result in a negligible cumulative effect local to the works at the container terminal. As the changes in water levels bought about by the berth 201/2 project are negligible, then the combined effects of the berth 204/5 dredge (which is several orders of magnitude smaller than the berth 201/2 project) are also considered to be negligible. The cumulative impact is of a scale that it is not considered significant to the hydrodynamic regime of the estuary. Changes to water levels resulting from Berth 201/202 works are limited to the locality of Berth 201/202. Therefore, there will be no cumulative and/or in-combination impacts from changes to water levels from any developments that occur outside of the immediate area of the container terminal.

Insignificant None required -

Flow speeds The additional developments, particularly the Town Quay and Royal Pier/ Mayflower Park reclamation and the Southampton Approach Channel Dredge, will cause a deviation of estuary flows in the area where Berth 201/202 is predicted to marginally change flows in the Test Estuary (up to ±0.02m/s). The contribution of the changes in flows brought about by Berth 201/202 is up to 20% of the changes to flows brought about by the additional developments and limited to the area local to Berth 201/202 and at the cruise terminal and Mayflower Park area. Berth 201/202 will generally result in changes in the opposite direction to the combined effect of the other developments i.e. providing some offset to the overall effect, should all the other developments take place. There would, therefore, be no significant cumulative effect to flows as a result of the Berth 201/202 and other

Insignificant None required


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developments. If anything, the Berth 201/202 would offer a beneficial measure, albeit negligible, of reducing the increased flows that are predicted to result, predominantly due to Town Quay and Royal Pier/Mayflower Park Development. As the changes in flow speeds brought about by the berths 201/2 project are negligible and will be impossible to measure directly in the field (para 8.91), then the effects of the berth 204/5 project (which is several orders of magnitude smaller than 201/2) are also considered to be insignificant. There will be no additional effect on the peak flow dynamics of the estuary downstream of Dock Head or the channel areas of the Central Solent as a result of the Berth 201/202 works. Therefore, there will be no cumulative and/or in-combination impacts from changes to flow speeds with any developments proposed downstream of Dock Head.

Suspended sediment concentrations

The changes in suspended sediment concentrations brought about by the additional developments are negligible. Suspended sediment concentrations will be marginally reduced (generally less than 2mg/l), predominantly due to the Southampton Approach Channel Dredge alone. The reduction in suspended sediment concentrations resulting from the Berth 201/202 works alone (up to 0.1mg/l) will only occur at certain states of the tide. Although, there will be a cumulative effect to suspended sediment concentrations should all developments take place, the Berth 201/202 works and berth 204/5 works will only make a small contribution (around 5%) to the overall negligible changes predicted. Therefore, the cumulative and/or in-combination impacts from changes to suspended sediment concentrations are considered to be insignificant to the sediment regime of the estuary. There will be no additional effect on the suspended sediment concentrations downstream of Fawley as a result of the Berth 201/202 works. Therefore, there will be no cumulative and/or in-combination impacts from changes to suspended sediment concentrations with any developments proposed downstream of Fawley and in the Solent.


Sedimentation and maintenance dredging

The Mayflower Park development would increase sedimentation rates by up to about 0.05m/year in the immediate lee of the works, which will very marginally increase maintenance dredging in the berths of the Western Docks and potentially create a new requirement across the entrance to Town Quay Marina and the marina itself. The negligible additional sedimentation predicted to result from the Berth 201/202



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redevelopment over this same area of up to 0.015m/year, together with the 204/5 widening (which is several orders of magnitude smaller than berths 201/2), is considered to be negligible with respect to the overall magnitude and variability in maintenance dredging commitment that is already required at the berths. The only other interaction with the changes to sedimentation brought about by the Berth 201/202 works is with those resulting from the Southampton Approach Channel Dredge. The Southampton Approach Channel Dredge will result in an additional maximum sedimentation of 0.01m/year in the berth pocket. The overall increase from existing maintenance requirements, if both the Berth 201/202 works and Southampton Approach Channel Dredge were to go ahead, will be around 2 dredger loads over a period of 10 years, which is considered negligible. However, the modelling does not include redistribution of sediment from the disturbance to the pocket from vessels. The maintenance dredging commitment is, therefore, expected to be slightly higher than indicated by the modelling. Overall, the cumulative and/or in-combination impact of Berth 201/202 works with other developments is considered insignificant, with respect to the sediment regime and maintenance dredging commitments in the estuary. There will be no interactive effect on the sediment regime downstream of Mayflower Park as a result of the Berth 201/202 works. Therefore, there will be no cumulative and/or in-combination impacts from changes to sedimentation patterns with any developments proposed downstream.

Underwater noise and water quality impacts during construction

It is likely that the timescales of the redevelopment of Berth 201/202 will overlap with those of the proposed Southampton Approach Channel Dredge. There is, therefore, the potential for an in-combination impact to occur to nature conservation features, particularly fish, as a result of underwater noise and changes to water quality acting together. ABP have committed to implementing an environmental window as mitigation for the impact to migratory salmon whereby percussive piling activities will be undertaken between mid September and end March when the potential for migratory salmon to be present in Southampton Water or the Test Estuary is at a minimum (Para 12.62). The residual

Minor adverse significant

None required -


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impact to migratory salmon will be insignificant to minor adverse significant. With the proposed adaptive management strategy that will be implemented as mitigation for the Southampton Approach Channel Dredge, which is based around monitoring of suspended sediment concentrations and dissolved oxygen during dredging, the most significant water quality changes in the estuary will be minor adverse significant. Therefore, the in-combination impact to migratory salmon of both constructions works occurring at the same time is considered to be minor adverse significant. All other operations were not considered sufficiently noisy to result in a significant impact and, therefore, the in-combination impact with water quality changes will be minor adverse significant at worst. It is possible that widening of berths 204/5 could take place at the same time as the percussive piling element of 201/2. [Simultaneous dredging of 201/2, 204/5 and the SACD would not occur as the same dredging plant is required for these 3 projects.] The 204/5 dredge will require the removal of an estimated 8 barge loads of material intermittently over a 10 day period when the berths are not in use. Water quality impacts arising from the berth 201/2 project are considered to be insignificant to at worse minor adverse significant for short periods (Chapter 10). The effects of the widening of berths 204/5 project (which is several orders of magnitude smaller than the berth 201/2 project) are, therefore, also considered to be insignificant to (at worst) minor adverse significance for short periods. For fish other than migratory salmon, the in-combination impacts will be less significant as they are less sensitive to a migratory barrier and more likely to avoid areas with adverse conditions, returning when conditions have improved. For these fish, the impacts will at worst be minor adverse significant. There is also the potential for an increase in water temperature as a result of the cooling water discharge from the proposed Helius Biomass Generating Station to interact with either the piling and/or dredging construction activities at Berth 201/202. This interaction could result in an in-combination impact on nature conservation features, particularly fish. According to the Scoping Statement that was prepared by Helius Energy Plc in September 2010, the water will be discharged from the station via one of two routes: either adjacent to the mouth of the King George V Dock at Berth 109 or into Southern Water’s mains sewer.


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Either option will be subject to water quality monitoring and, if applicable, environmental permitting. Hydrological modelling is being undertaken as part of the Helius EIA to predict the likely spatial dispersion of heated water discharge into the River Test. The results of this work are not yet available publicly and, therefore, it is not possible to quantify the scale of the potential interactive effect at this stage. The detailed assessment of the Helius proposal will, therefore, need to fully assess the significance of the cumulative and in-combination impacts with the Berth 201/202 application.

Disposal of arisings at the Nab Deposit Ground

The arisings derived from the Berth 201/202 capital works comprise around a 20% increase to that from existing maintenance dredgings disposed of at the Nab Deposit Ground. If the Southampton Approach Channel Dredge and Portsmouth Harbour Approach Dredge were to take place at the same time as the Berth 201/202 works, there is the potential for a cumulative/in-combination impact to result from the combined effects of disposal of arisings at the Nab Deposit Ground. Given that the materials being dredged from the berth pocket are a very small proportion of the proposed material to be disposed of from all three proposals (1%), the contribution of Berth 201/202 to the magnitude of the combined impact is considered to be negligible to low. However, it is important to note that an initial accumulation of sediment is likely to occur within the deposit ground before the backhoe dredged material breaks down to its fine-grained component form over time. The probability of all three projects occurring at the same time, however, is low, although it is likely that the timescales of the Berth 201/202 works will overlap at some point with that of the Southampton Approach Channel Dredge. Therefore, the overall exposure at the Nab Deposit Ground to cumulative and/or in-combination impact is considered to be moderate. Given the low sensitivity to existing maintenance dredge deposits and the nature conservation and commercial fishery importance of the area, the cumulative and/or in-combination impact is considered to be minor adverse significant. The capital dredge of berths 204/5 represents approximately 3% of the proposed 201/2 capital dredge and less than 1.5% of the Port’s permitted annual maintenance dredge. The magnitude of change at the deposit ground is very small compared to existing maintenance and capital dredge deposits of similar sediments at the site. Such deposits

Minor adverse significant

None required

-


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have not raised concerns in the past (para 8.67) The overall impact is, therefore, considered to be insignificant.

Ship Wash The size of vessel generated waves brought about by changes in the maximum size of container vessels that can be accommodated by the proposed berth 201/202 project will change as a result of the widening and deepening of the main navigation channel proposed by the Southampton Approach Channel Dredge. Calculations of wave heights at the shore as a result of both projects interacting reveal that if the main channel is widened and deepened, the wave heights generated at the shore by 15.5m draught container vessels will reduce by up to 1cm (circa 4%). The reason for this is that the deepened channel allows a greater depth for the oscillatory motion of water particles and lesser disturbance of wave shape by the seabed. It is possible that the relaxation in tidal access constraints resulting from the deepening of the channel could allow more of the deepest-draughted container vessels to gain access to the Container Terminal than is currently possible. The ship wash analysis presented in Chapter 16 investigates the effect of an increased proportion of the largest vessels, and concludes that there would be a reduction in vessel-generated wave energy. In any case, the natural variability in the existing wind-wave environment exceeds that from any change in vessel generated wave energy resulting from an increase in the maximum container vessel size in-combination with the widening and deepening of the main channel in Southampton Water. Nevertheless, the Southampton Approach Channel Dredge will create a small improvement (reduction) in the wave energy generated by vessels that can be accommodated by Berth 201/202. The cumulative and/or in-combination ship wash impact is, therefore, considered to be minor beneficial significant.

Minor beneficial significant

None required -

Airborne noise It is possible that the Berth 201/202 works could occur concurrently with the proposed Southampton Approach Channel Dredge and 204/5 widening project. Full details of the main channel improvement project are given in a separate Environment Statement, however the dredging operations for this these projects are most likely to require a large backhoe dredger and a large trailing suction hopper dredger (TSHD) to be used. The dredging operations will occur 24 hours per day, 7 days per week. During the night-time, some operational restrictions are likely to be placed on dredging operations where the main channel is close to residential or other noise sensitive properties. This applies

Major adverse significant at worst (depending on the type of backhoe dredger used for the Southampton Approach Channel Dredge and works occurring together in the local

Backhoe dredging may need to be avoided in either all, or part of, the main channel in the vicinity of Admiralty Quay, during periods of percussive piling operations for Berth

-


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especially to the Admiralty Quay area where the southern boundary of the main channel runs within 50m of the properties on this estate. There will be no in-combination night-time environmental noise impact as a consequence of this exclusion zone and also as no night-time construction activities are envisaged for Berth 201/202. During the daytime, however, a significant in-combination environmental impact may be experienced depending on the phasing of the construction activities, the type of dredger working in the vicinity of Admiralty Quay, and the actual location of this dredger. The maximum noise level predicted from Berth 201/202 construction activities is 71 dB LAeq 1h (free field). Depending on the type of backhoe dredger used, the maximum noise level from this could be 70 dB LAeq 1h (free field) at the nearest Admiralty Quay property. As a consequence, the total noise level could rise to over 73 dB LAeq 1h (free field), which would be of major adverse significance (76 dB LAeq façade). When dredging berths 204/5, the noise levels from this activity at the nearest Admiralty Quay property are calculated to range from 49 to 58 LAeq 1hr (free field) in a downwind direction, taking into account the distances of berths 204/5 from Admiralty Quay and assuming the use of a large backhoe dredger. These lower levels of noise will add insignificantly to the noise levels predicted for the construction of 201/2, and will also be of short duration. No in-combination impact of significance is predicted from the use of the TSHD in the vicinity of Admiralty Quay, during percussive piling.

area). Insignificant (assuming a TSHD is required).

201/202. If however, a dredger was employed which in-combination with the construction noise resulted in a total noise level of less than 72 dB LAeq 1h (free field), then ABP would undertake both activities simultaneously.

Road and Rail Transport

For the reasons explained in detail in chapter F1 and the supporting detailed Transport Assessment (Appendix M) the road traffic changes resulting from the other relevant projects identified will not result in any significant changes to the conclusions of the Road Traffic assessment undertaken for the project alone. A similar conclusion is reached in respect of the Rail Traffic assessment. For the avoidance of doubt, the road and rail assessments are based on a figure for total terminal capacity of 2.8M TEU per annum. The 2.8M TEU capacity is a function of berth and yard capacity (as explained in chapter 7) and is therefore unaffected by vessel size or the widening scheme for berths 204/5.

Insignificant/Minor Road and Insignificant Rail (i.e. the same overall conclusion as reached for Berth 201/202 alone)


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Landscape and Visual

Cowes Breakwater, Portsmouth Harbour Dredge and the Southampton Approach Dredge all lie outside of the Study Area and would not result in cumulative effects. In combination development around Southampton Water would lead to cumulative landscape character and visual effects. Woolston Redevelopment of Vosper Thorneycroft site, Town Quay / Royal Pier / Mayflower Park, Hythe Marine Park and Marchwood Marine Park are all redevelopment schemes with the potential to enhance the existing townscape fronting onto Southampton Water. Effects would be dependant upon the final scheme designs for these projects and are likely to balance many of the identified adverse landscape and visual effects of the Berth 201/202 Project on Southampton Water / River Test waterfront. In combination development around the Container Terminal would lead to cumulative landscape and visual effects. The new internal access road arrangements Dock Gate 20 and the Council Depot and Household Waste Recycling Centre north of the Container Terminal would lead to small scale local improvements to the townscape. The Warehouse club at British American Tobacco is the redevelopment of an existing warehouse and so there would be no significant landscape and visual effects. All three projects would not significantly alter the identified landscape and visual assessments for the berth 201/202 project. Helius Biomass Generating Station has been identified as having significant landscape and visual effects as a result of its siting and massing. In the projects current form HBGS would block identified views of the berth 201/202 project from Freemantle (e.g. VP 12 and 13). During the construction phase, effects would be as identified for the HBGS assessment. During the operational phase there would be no or only glimpsed views of the berth 201/202 project and therefore reduced or no operational phase visual effects would result from the Project. For other close-in views including Regents Park and Marchwood, the Helius Project may result in reduced significance of identified visual effects associated with the project due to the scale of the Helius building reducing the perceived scale of the new container cranes.

Minor to Moderate adverse (i.e. the same overall conclusion as reached for Berth 201/202 alone)

None Minor to Moderate adverse

Air Quality The Helius Biomass Generating Station would be located within the Southampton Port Insignificant (i.e. the


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Estate and would have potential impacts on nitrogen oxides and PM10 concentrations, as a result of emissions from the stack. An application for consent has not yet been submitted and therefore insufficient information is available to quantitatively consider the cumulative effects with this development. However, the peak concentrations from the stack are unlikely to occur at the same locations as would be affected by road and rail traffic. The majority of biomass would be delivered by ship. At most it is considered that around 39 lorry loads of material would be delivered per day. This is very small in relation to existing traffic in the network and unlikely to alter the conclusions of the assessment of the project in its own right.

same overall conclusion as reached for Berth 201/202 alone)

Cultural Heritage

The only other project considered to have potential in combination cultural heritage effects with the project is the Helius proposal. The relevant available cultural heritage information relating to the Helius proposal indicates that there would be a slight adverse effect on the King George V dry dock. All other relevant impacts on the historic environment are considered to be neutral.

Slight adverse effect on the King George V Dry dock in combination with the Helius project (however, this effect is brought about by the Helius scheme). All other effects remain as reported for berth 201/202 alone.

Operational Noise

The only other project of potential significance is considered to be the Helius Biomass Generating Station. Available information on operational noise generated by this proposal refers to operational noise limits being placed on the development. The suggested noise limits are low compared to the noise levels identified for the Berth 201/202 operational noise assessment. No significant combined operational noise effect is therefore considered likely to be generated.

Insignificant.

Socio Economic

The other projects considered have the potential to generate economic benefits. None of these are predicted to change the conclusions reached in respect of the berth 201/202 works in their own right.

Major Beneficial (i.e. the same overall conclusion as reached for Berth 201/202 alone)


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Summary

18.8 The potential additional effects of this proposal with other proposed developments were considered. The other plans and/or projects included the Southampton Approach Channel Dredge, Marchwood Marine Park, Cowes Breakwater, and Royal Pier/Mayflower Park Development, the widening of berths 204/5, Helius Biomass Generating Station, internal Port access road proposals, Council Depot / Recycling Centre, and redevelopment of part of BAT site.

18.9 No evidence of any cumulative and/or in-combination effects as a result of following the

proposed dredge element of between the projects and other plans or projects downstream of Fawley were identified. The only interactive effects were with those developments that occur up estuary of Dock Head. Overall, the impacts of these developments on the hydrodynamic and sediment transport regimes will be insignificant.

18.10 During construction, there is the potential for in-combination impacts to occur to fish due to the

interaction of underwater noise and water quality impacts between the Southampton dredge or 204/5 berth widening proposal and Berth 201/202 construction activities should they occur at the same time. These impacts are assessed as minor adverse significant. There is also a potential for interaction to occur as a result of the cooling water discharge required for the Helius Biomass Generating Station. The biomass station proposal is not sufficiently advanced at this stage to quantify the scale of any interactive effect. Any such in combination effects can only be considered as part of the EIA that is undertaken for the Helius Energy Plc development. Cumulative impacts due to the disposal of arisings at the Nab Deposit Ground occurring at the same time will be minor adverse significant, although the contribution of Berth 201/202 works to such impacts would be negligible (around 1%). There is also the potential for significant cumulative environmental noise impact on residents at Admiralty Quay to occur between the Berth 201/202 construction activities and the Southampton dredge. If backhoe dredging is required for the channel dredge, mitigation is proposed under the Southampton Approach Channel Dredge project, by way of avoiding the vicinity of Admiralty Quay during periods of percussive piling operation for Berth 201/202 to reduce the impact to acceptable levels.

18.11 The Helius Biomass Generating Station has been identified as having significant landscape and visual effects as a result of its siting and massing. In its current form HBGS would block identified views of the project from Freemantle e.g. VP 12 and 13 and therefore result in reduced or no visual effects being identified for these viewpoints as a result of the Project. For other close-in views including Regents Park and Marchwood, the Helius Project may result in reduced significance of identified visual effects associated with the project due to the scale of the Helius building reducing the perceived scale of the new container cranes.

18. cumulative and in-combination effects projects/18... · the in-combination effects of...

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