portland house, bressenden place, london environmental ... · below ground, the site houses the...

Portland House, Bressenden Place, London Environmental Statement - Non-Technical Summary

February 2013

on behalf of LS Portland House Developer Ltd

Portland House ENVIRONMENTAL STATEMENT: NON-TECHNICAL SUMMARY

Page 1 of 20

1. INTRODUCTION

LS Portland House Developer Limited (hereafter referred to as the ‘Applicant’) is seeking to obtain detailed planning permission for the refurbishment, re-cladding, remodelling and change of land use (to predominantly residential land use) of the existing office-led Portland House, together with associated landscaping and car parking within Victoria, in the City of Westminster, London (hereafter referred to as the ‘Development’). Above ground, the Development encompasses an area of approximately 1.3 hectares (ha). Below ground, the Development encompasses an area of approximately 2.1ha. The above and below ground red line planning application boundaries collectively comprise the site of the Development (hereafter referred to as the ‘Site’).

Ground Floor Planning Application Boundary


Page 2 of 20

Typical Upper Floor Planning Application Boundary

Below Ground Planning Application Boundary


Page 3 of 20

The Site is broadly bounded by Palace Street and the mixed-use buildings of Cardinal Place to the north; the 17-storey residential building ‘The View’ and other mixed-use buildings of Cardinal Place to the east; Victoria Street and further mixed-use buildings (predominantly ground floor retail with offices above) of Cardinal Place to the south; Bressenden Place to the west; and the office building Eland House and the Phoenix Public House to the northwest. Below ground, the Site comprises an existing basement which is common to the existing Portland House, Cardinal Place and The View, in addition to a smaller, mezzanine level. For this reason, the below ground Site extends not only beneath the existing Portland House building, but also beyond the northeast footprint of Cardinal Place.

An Environmental Impact Assessment (EIA) has been undertaken to assess the environmental effects of the Development. The EIA is reported in an Environmental Statement (ES) which has been prepared to accompany the planning application. The ES describes the likely significant environmental effects of the Development. This document provides a summary of the ES in non-technical language.

2. ENVIRONMENTAL IMPACT ASSESSMENT METHODOLOGY

EIA is a process which aims to ensure that the likely significant environmental effects of a proposed development (which can be beneficial and / or adverse) are given due consideration in the determination of a planning application. In accordance with the relevant legislative requirements and best practice guidelines, the EIA was undertaken using established methods and criteria. This involved visits to the Site, along with surveys, data reviews, consultation with a number of relevant statutory authorities, computer modelling and specialist assessment undertaken by a team of qualified and experienced consultants.

The first stage of the EIA process involved undertaking a ‘Scoping Study’. The purpose of the study was to identify the potentially significant environmental effects associated with the Development and therefore the focus or scope of the ES. The Scoping Report which presented the findings of the Scoping Study was submitted to Westminster City Council (WCC) to support a request for their ‘Scoping Opinion’. A Scoping Opinion was received from WCC in December 2012.

It was agreed with WCC that the Portland House EIA would need to include an assessment of the following environmental topics:

Deconstruction and construction effects;

Waste management;

Townscape, conservation and visual effects;

Socio-economics;

Transportation and access;

Air quality;

Noise and vibration;

Archaeology;

Ground conditions and contamination;

Water resources and flood risk;

Wind;

Daylight, sunlight, overshadowing, light pollution and solar glare; and

Cumulative effects.

Each environmental assessment topic is reported in the ES as a ‘technical chapter’. Each technical chapter describes how the assessment was undertaken, the relevant environmental conditions on and adjacent to the Site and the potential likely significant effects of the Development. Each technical chapter also describes a range of measures that would be incorporated to avoid, reduce, or offset any identified potential adverse effects, and / or enhance potential beneficial effects. Such measures are referred to as ‘mitigation measures’. The resulting effects (known as ‘residual effects’), following the implementation of mitigation measures, are also described.


Page 4 of 20

It is important to note that the Site lies within the area captured by WCC’s Victoria Area Planning Brief (VAPB) Supplementary Planning Document (SPD), adopted in July 2011. As such, there are significant consented proposals adjacent to the west of the Site which are currently being implemented and are likely to be completed and operational approximately about the same time, or prior to the completion and operation of the Development. Such consented proposals are London Underground Limited’s (LUL’s) Victoria Station Upgrade (VSU) proposals and the Applicant’s Victoria Circle development. This necessitates the following facts and reasonable assumptions to be applied to the EIA:

The existing baseline conditions to the immediate west of the Site are constantly changing and represent only temporary and interim conditions;

The pre-VSU and pre-Victoria Circle baseline conditions do not exist and cannot ever reasonably exist within the future;

As a result of the above, the likely significant environmental effects resulting from the completed and operational Development will have to be assessed against a set of ‘likely future baseline’ conditions which assume the full implementation of the consented and currently under construction VSU and Victoria Circle developments, which are likely to be fully operational or built out in or by the opening year of the Development; and

Although it is recognised that the Applicant’s consented Victoria Circle proposals could result in any one of four ‘Development Scenarios’, it has always been the stated intention of the Applicant to implement Victoria Circle Development Scenario 1. In addition, given that consent has been achieved for all three detailed planning applications and recent Minor Material Amendments to Victoria Circle (Planning Refs: 12/07186/NMA; 11/05097/FULL and 08/08207/FULL), Permission 1 which constitute Development Scenario 1, it is deemed reasonable and likely that the consented Victoria Circle Development Scenario 1 will be fully implemented. The likely future baseline conditions will therefore account for the consented Victoria Circle Development Scenario 1 only.

Similarly a number of other consented schemes within the wider vicinity of the Site (owned by the Applicant) will also be operational prior to, or close to, the year of opening of the Development. Such schemes include 62 Buckingham Gate, Wellington House, Kingsgate House and The Former Look Ahead Hostel, Castle Lane Scheme. These schemes are therefore also considered as part of the likely future baseline.

3. EXISTING AND LIKELY FUTURE LAND USES AND ACTIVITIES

Above ground, the Site is currently occupied by the 1960’s 30-storey concrete office-led building, Portland House, together with the predominantly canopy covered and retail fronted pedestrianised areas associated with Cardinal Place. These pedestrianised areas are known as Cathedral Walk (in the northwest and the southeast of the Site) and Cardinal Walk (in the southwest of the Site). Along the entire west of the Site runs the eastern pedestrian footway of Bressenden Place. Along this eastern pedestrian footway are two pavillion structures providing access to the subsurface gym within Portland House.

Within the east of the Site is a raised and terraced public amenity area (raised above a ground floor retail unit), which can be accessed at the junction of Cathedral Walk and Cardinal Walk by a set of stairs and escalators. Within the west of the Site, adjacent to the northwest corner of the existing Portland House, is a large sculpture known as the ‘Big Painting’.

The existing Portland House provides 38,205m2 Gross External Area (GEA) of office space, 876m

2

retail space and 1,191m2 GEA of gym space. The office space is located at floors 1 - 29 above a

ground floor reception area. The retail space is provided as a restaurant and a shop. The leisure space is associated with a basement level gym operated by LA Fitness.

Below ground, the Site houses the aforementioned LA Fitness gym, 86 car parking spaces associated with Portland House and a servicing area.

Land uses and activities surrounding the Site are diverse with those in the immediate vicinity, or of particular significance, including:

Cardinal Place, providing retail and office land uses adjacent to the north, southeast and south of the Site;


Page 5 of 20

Residential dwellings northeast of the Site, north of Palace Street;

The View (Roebuck House) providing 17-storeys of residential land use adjacent to the east of the Site, including a basement gym – Fitness First;

The Grade I listed Westminster Cathedral located to the southeast of the Site;

The Grade II* listed Victoria Palace Theatre located southwest of the Site on the north side of Victoria Street, together with the adjacent unlisted Duke of York pub;

Ground floor retail units and upper level offices on Victoria Street to the immediate south of the Site, with Terminus Place and the Grade II listed Victoria Station further to the southwest, providing mainline rail and London Underground Limited (LUL) services, as well as bus and coach services;

The Grade II* listed Grosvenor Hotel to the west of Victoria Station;

Office buildings located along Bressenden Place to the west and northwest of the Site, including Eland House;

The Phoenix Public House and St. James Theatre, adjacent to the northwest of the Site;

The Grade I listed Royal Mews and Buckingham Palace Gardens located to the northwest of the Site; and

The Royal Parks (Green Park, St James’s Park and Hyde Park) located north, northeast and northwest of the Site respectively.

The Grade II* Listed Grosvenor Hotel (Located to the Southwest of the Site)

The Grade I Listed Buckingham Palace Mews (Located to the north west of the Site)

The View Located to the East of the Site (viewed from within Cardinal Place)

The Southwestern Building of Cardinal Place (Located at the Victoria Street / Cardinal Walk Junction)

Photographs of the Site’s Surroundings


Page 6 of 20

As noted earlier within this NTS, a number of consented schemes within the vicinity of the Site are likely to be completed and operational approximately about the same time, or prior to the completion and operation of the Development. A summary of such consented schemes, and their location in relation to the Site, are provided as follows:

Victoria Circle – a mixed-use scheme adjacent to the western boundary of the Site, comprising five new buildings, basement, significant public realm and new pedestrian routes;

Victoria Underground Station Upgrade (VSU) – Significant improvements to Victoria Underground Station, including new access, extension of existing ticket hall and a new ticket hall, and new connections to other underground lines. The new station access will be immediately adjacent to the southwest boundary of the Site;

Former Look Ahead, Castle Lane scheme – a refurbishment scheme of four existing hostel blocks to provide 63 affordable housing units. It is located to the northeast of the Site;

Kingsgate House – two new buildings (one office-led, one residential-led) fronting Victoria Street, adjacent to the east of Cardinal Place and Palace Street and the west of Westminster City Hall;

62 Buckingham Gate – an office-led scheme located on the north of Victoria Street, comprising a single 12-floor building, with basement; and

Wellington House – a residential scheme comprising one building, located to the northeast of the Site.

4. ALTERNATIVES AND DESIGN EVOLUTION

In line with the UK regulations which relate to EIA, the ES provides a description of the main alternatives to the Development which were considered by the Applicant, together with a description of the design evolution of the Development.

Guidance on the preparation of EIA suggests that it is good practice to consider ‘alternative sites’. However, given that the Development has arisen from the need to refurbish / develop the existing Portland House building, the proposals are specific to the Site and its emerging context. Accordingly, no alternative sites were reasonably considered by the Applicant.

EIA Guidance also suggests that the option of doing nothing (the ‘do-nothing’ alternative) is also considered in an ES. The ‘do-nothing’ alternative would entail leaving the Site in commercial use, with office and retail dominating the land use mix. By leaving the Site in its current state, no new homes would be created at the Site and the opportunity to improve and enhance the local and wider townscape, together with long-distance and local views would be lost. This would go against relevant National, Regional and Local planning policies, including those of The London Plan and WCC’s VAPBA. The ‘do-minimum’ alternative would entail the refurbishment of the existing Portland House, but maintain its existing office land use. Again, this would not achieve relevant National, Regional and Local planning policies.

An alternative comprising retaining office use was also considered, however a viable commercial development would come at the cost of a larger Portland House. This was considered to be unacceptable in relation to townscape and visual considerations.

On establishing the need and acceptability for a residential-led refurbishment, re-cladding and remodelling proposal, the Applicant and their design team worked up a Development in which the overall design, massing, external materiality and landscaping was informed by the Site’s constraints and opportunities; particularly those relating to townscape and visual matters, microclimate, and pedestrian permeability. The final Development design emerged as a result of these factors together with an extensive programme of consultation with officers at WCC and other statutory and non-statutory consultees.

5. THE DEVELOPMENT

The Development, designed by by David Chipperfield Architects (DCA) and Vogt Landscaping Limited would involve the refurbishment, re-cladding and remodelling of the existing Portland House building together with a change of land use from office and retail to residential and retail use, with facilities ancilliary to the residential use including a gym, swimming pool / spa and amenity space.

The Development would provide a total floorspace of 53,809m2 Gross External Area (GEA WCC).

This would provide 206 new residential units (at Level 02 and above), an ancillary gym, swimming


Page 7 of 20

pool / spa (at basement level), a shared amenity space (a ‘residents’ room at first floor level) for private residential use, together with 1,233m

2 GEA of ground floor retail, including basement retail

storage and first floor retail. The Development would also provide 6,251m2 GEA of private amenity

space in the form of balconies and roof terraces, Up to 151 car parking spaces and 294 cycle spaces would be provided, alongside adequate servicing and storage facilities.

Whilst the core of the existing Portland House building would be retained, deconstruction and construction activities would be required to extend and off-set the existing floorplates of Portland House. The extension, splitting and off-setting of the existing floorplates would create two distinct elements to the remodelled Portland House: the eastern element and the western element. The proposed Portland House would be no higher than the existing Portland House building (106.14m AOD). However, there would be a slight reduction in height to the western portion of the building. As such, the eastern portion of the proposed Portland House would extend to 99.94m Above Ordnance Datum (AOD). The western portion of the proposed Portland House would extend to 90.74m AOD.

The proposed plan form of the eastern and western elevations of Portland House would be curved. This is intended to soften the overall form from the existing situation. The Development would make use of the existing basement, whereby the aforementioned car parking is proposed in the existing basement beneath Portland House, Cardinal Place and the View (20 Palace Street). There would be reorganisation of existing car parking spaces so as to segregate spaces allocated to the proposed Portland House. The Development would provide electric charging points to 50% of the car parking spaces.

The landscape proposals seek to re-orientate Victoria and Portland House towards the Royal Parks to the north of the Site and extend the ‘park’ qualities south into Victoria, through the introduction of soft landscaping in the form of trees along Bressenden Place and Cathedral Walk.

In addition, the landscape proposals would redefine the central arcade of Cardinal Place and the existing Cardinal Place roof garden to include a central topographic lawn for use as an amenity area. This would allow a link between Victoria Street and the proposed Portland House. The existing curved glass canopy will be replaced. A new canopy structure will be connected to the existing Cardinal Place buildings, existing external columns and the proposed Portland House. The canopy will have a circular opening in the centre to expose a tree below. It will also extend partly over the existing roof terrace.

Energy efficient measures have been incorporated into the design to reduce the heating, energy and electrical demands of the Development. Within the Development, four gas-fired boilers, along with Photovoltaic (PV) panels would be included. A geothermal heat pump system would be included subject to viability. In addition, it is anticipated that the Development would be connected to the adjacent Victoria Circle energy centre for district heating. These measures would provide approximately 60.5% savings in carbon over the Building Regulations 2010 compliant baseline scheme.


Page 8 of 20

Ground Floor Plan


Page 9 of 20

Typical Upper Floor Plan and Canopy


Page 10 of 20

Section Drawing of Portland House

6. DEVELOPMENT PROGRAMME, DECONSTRUCTION AND CONSTRUCTION

It is envisaged that the overall deconstruction and construction of the Development would last approximately 3 years 9 months, completing in 2018. A further period would then be required for retail tenant fit-out (this would not be undertaken by the Applicant), which is anticipated to be within the first quarter of 2019. It is anticipated that the deconstruction and construction works would comprise the following main stages:

Enabling works and deconstruction;

Piling works;

Substructure works (including limited excavation);

Basement fit-out (including mechanical engineering and public health (MEP) works)


Page 11 of 20

Superstructure works (frame only);

Cladding and roofing;

Fit-out to landlord areas (corridors/basement/service areas);

Fit-out to residential apartments;

Commissioning; and

External works / public realm works.

In order to control and manage the potential environmental effects of deconstruction and construction, a site-specific Environmental Management Plan (EMP) would be developed. This would be implemented throughout the duration of the works and would specify a range of measures to manage the environmental effects that could arise during deconstruction and construction works. Examples of controls specified within the EMP would be construction traffic management, waste management and controls in relation to dust, noise and vibration.

The site-specific EMP would be prepared in line with relevant legislative and best practice guidelines. Specific regard would be given to WCC’s ‘Code of Construction Practice’. Contractors would be required to implement the EMP and ensure that environmental monitoring is also undertaken where this has been specified.

EMPs are an established method of managing environmental effects resulting from deconstruction and construction works and are consistent with other methods successfully adopted for other major schemes in urban areas.

7. WASTE MANAGEMENT

A waste management assessment has been undertaken using a wide range of information sources. These sources include a detailed review of planning policies, guidance and standards and professional experience of similar development schemes.

An assessment has been undertaken to establish the volumes of waste which would be likely to arise from both the deconstruction and construction works and the operation of the Development. Consideration has then been given to the proposed waste management and servicing strategy associated with the Development.

Although deconstruction and construction would generate large volumes of waste, the Applicant is committed to reusing or recycling 90% of all deconstruction and construction waste, in addition to sending less than 10% of waste produced from the works to landfill.

The implementation of a Site Waste Management Plan (SWMP) would facilitate the reduction, re-use and recycling of deconstruction and construction waste. As such, the volume of waste going to landfill would be minimised as far as practically possible. All demolition and construction waste would be managed in accordance with relevant legislative requirements.

It is estimated that the Development would generate approximately 30.2m3 per week of residential

waste, 0.03m3 per week of gym waste (which is ancillary to the residential use) and 0.11m

3 per week

of retail waste. This represents a significant decrease over the existing office use.

When operational, the Development would provide facilities to recycle approximately 60% of household waste generated and at least 66.6% of the waste generated by retail uses. The actual rate would be dependent on the participation of future occupants. The Development therefore incorporates sufficient recycling storage in suitable locations to facilitate recycling in accordance with the National Waste Strategy and the Mayor’s Preferred Standards outlined in the Mayor of London’s Supplementary Planning Guidance on Sustainable Design and Construction. Information would be provided to commercial and residential occupants of the Site to promote the recycling of waste.

8. TOWNSCAPE, CONSERVATION AND VISUAL EFFECTS

The townscape, conservation and visual assessment report prepared by Richard Coleman CityDesigner has assessed the effect of the Development on the existing built environment and its general townscape. The assessment includes consideration of local and distant views, together with effects on other sensitive environments including areas of cultural heritage value, effects upon listed buildings, strategic views, conservation areas and the Westminster World Heritage Site (WHS).


Page 12 of 20

The deconstruction and construction of the Development would involve the use of a range of plant and equipment which are likely to give rise to temporary adverse effects on townscape, conservation and views.

The Site does not fall within a conservation area and the existing building on the Site is not listed. In vicinity to the Site lies the Grade II* listed Victoria Palace Theatre, in Victoria Street. To the south-west of the Site is the Grade II listed Victoria Railway Station and the Grade II* listed Thistle Grosvenor Hotel. As part of the on-going VSU works, the Grade II listed ‘Little Ben Clock’ has been temporarily removed to be stored and refurbished and will be re-erected at the junction between Victoria Street and Vauxhall Bridge Road once the VSU works near completion. To the west are Buckingham Palace Road and Grosvenor Gardens, which are within Belgravia and Grosvenor Gardens Conservation Areas, and include a number of listed buildings. The Grade I listed Westminster Cathedral is located to the south east.

The Development would have a range of effects on, or would be visible from the wider townscape, listed buildings, conservation areas, London Squares, Royal Parks, Westminster World Heritage Site (WHS) and Buckingham Palace. Effects are established by way of Accurate Visual Representations (AVRs) of townscape and distant views and local views with the aid of ‘before’ and ‘after’ photographs and computer model views which include the Development superimposed accurately into the frame.

The views to be considered in the assessment were agreed with WCC officers and English Heritage. A number of views were identified (43 AVRs and 9 computer model views), with reference to the policies within the London Plan, London View Management Framework (LVMF) and the City of Westminster Unitary Development Plan (UDP).

View from Buckingham Palace Road Junction


Page 13 of 20

View from Bucking Palace Gardens (lake west) (winter) with Victoria Circle in foreground

View from Catherine Place


Page 14 of 20

From a review of the AVRs no adverse effects are concluded. The Development satisfies all policy aspirations and is tested against the requirements set out in the Westminster World Heritage Site Management Plan and the London View Management Framework. It has been demonstrated that the Development preserves the Outstanding Universal Value of the WHS. Furthermore improvements to the legibility and quality of the public realm together with high quality design are considered to predominantly bring about significant townscape, conservation and visual benefits.

9. SOCIO-ECONOMICS

A socio-economic assessment has been undertaken using a wide range of information sources. These sources include a detailed review of planning policies, guidance and standards, population Census data and professional experience of similar development schemes.

The assessment establishes that during the estimated 45 month deconstruction and construction programme an equivalent of 288 full time construction jobs would be generated.

There are approximately 2,250 office workers employed at the Site. The Development includes no office space, so all of these workers would be lost from the Site. However, given the business activity of the current occupants which requires location in Inner London, it is expected that up to 75% of this employment would be displaced within Westminster. In addition with the closure of the commercial gym and swimming pool / spa ancillary to the residential use of the Development, there would be a loss of approximately 8 employees.

The Development would bring about an increase to the existing on-Site retail provision, by approximately 10 employees. In addition, there are likely to be jobs associated with the proposed residential floorspace, such as concierges, facilities management and other building operatives and staff and management staff. These are considered to have the potential to yield up to 10 jobs.

The Development would provide 206 residential units ranging in size from studio to 4 bedroom units. All residential units would be private.

The population of the Development is estimated to be approximately 387 permanent residents. This increase in population would create some additional demand for community facilities, especially education and healthcare. The number of children living in the Development is expected to be low; a total of 45 including pre-school, primary and secondary school children, of which 29 would be primary school aged, and 12 would be secondary school age. Research indicates there is likely to be sufficient capacity within the seven primary schools located within 1km of the boundaries of the Site and within Secondary schools in WCC to accommodate these children.

There are 10 GP surgeries and 12 dental practices within 1.6km of the boundaries of the Site. The population in the Development would generate additional need for primary healthcare. It is estimated the population would generate the need for 0.22 of a GP and 0.31 of a dentist.

There would be increased levels of spending in the local area through the introduction of new residential populations within the Development. It is anticipated that the total additional spend attributed to the new population of the Development at the regional level would be approximately £5.1 million per year, and £2.7 million at the borough level.

Given the nature of the Development the scope for developing on-Site play space is limited, and as such the Development does not contain any formal on-Site provision for play space. However, at first floor level, a resident’s room is provided, which offers the opportunity for informal play space for children.

10. TRANSPORTATION AND ACCESS

A detailed study of the effects of the Development upon local highways, public transport, pedestrians and cyclists has been undertaken. This has been based upon a range of information sources and includes a detailed assessment of future traffic and computer modelling of pedestrian flows.

Based upon the anticipated deconstruction and construction timetable and the quantities of materials arising and required from the works, it has been predicted that even in the worst-case scenario, the contribution of deconstruction and construction traffic from the Development would be insignificant in the context of the high volumes of vehicular traffic flows in proximity to the Site. Notwithstanding this,


Page 15 of 20

the site-specific EMP would ensure that any temporary disruptions to the surrounding road network would be minimised and appropriately managed.

There are a wide range of public transport services existing within and in proximity to the Site. These include regional services provided by Victoria Mainline Station, services across London provided by Victoria Underground Station (served by the Victoria and District and Circle LUL lines) together with a comprehensive range of local and London-wide buses.

The increased provision of cycle parking for the Development would improve cycle facilities and help promote cycling as a transport mode. The Development would result in the need for the existing Cycle Hire facilities located to the northwest of the existing Portland House to be removed. An alternative location in the north part of Warwick Row is considered to be a potential viable alternative location for replacement facilities.

An assessment of the additional trip generation of the Development concludes that there would be a significant reduction in peak hour and daily trips on all transport modes to the Site due to a decrease in the density of people associated with a change from a predominantly office to a predominantly residential building. The commitment to implementing a Travel Plan would help to ensure car trips generated by the Development would be minimal. It is also likely that the proximity of the Development to a range of public transport services would further limit car use by future residents and occupiers of Portland House.

The Development would include up to 151 car parking spaces, which would utilise a valet parking system. Despite the increase in car parking proposed as part of the Development, trip generation forecasts indicate that there would be an overall reduction in car trips generated.

Servicing of the Development would continue to be provided off-street, at basement level.

11. AIR QUALITY

Due to the existing and predicted future levels of air pollutants primarily associated with vehicular traffic emissions, WCC has declared an Air Quality Management Area (AQMA) across the whole of the City of Westminster. Accordingly, an air quality assessment has been undertaken to determine the effects of the Development on local air quality and the AQMA.

The assessment has considered the likely effects of the Development on local air quality in relation to deconstruction and construction activities and the completed and operational Development. Predicted traffic flow data and energy plant was analysed using a complex computer model which calculated and predicted the likely resultant changes to local air quality. Within the future scenarios, the assessment has also considered the effects of predicted emissions from the adjacent Victoria Circle energy plant.

During the deconstruction and construction works, best practice measures would be implemented to minimise dust arising from the construction site. These measures would form part of the Site-specific EMP and would include the erection of hoarding around the construction site, ‘damping down’ of surfaces, the covering of all construction materials and the regular cleaning of frequently used areas. However, even with these measures in place it is difficult to completely eliminate the effects of dust on nearby receptors particularly under dry and windy conditions.

Emissions from construction plant would be minimised by switching off engines at all times when not in use. Furthermore, as described above in the discussion of transportation and access, deconstruction and construction generated traffic is not anticipated to significantly add to local traffic flows. As a result, the effect of emissions from deconstruction and construction vehicles would be minimal.

Regarding the effects of the completed Development, the complex computer modelling indicated that the minor changes in vehicular traffic as a result of trips generated by the Development and the emissions from the proposed heating plant would have a insignificant effect on ambient concentrations of nitrogen dioxide (NO2) and particulate matter (as PM10 and PM2.5) at existing sensitive residential receptors. In addition, the Development is considered suitable for introducing residential use.


Page 16 of 20

12. NOISE AND VIBRATION

The noise and vibration effects of the Development have been established in accordance with published guidelines and this included a comprehensive baseline monitoring survey of the Site.

Deconstruction and construction activities would inevitably give rise to some noise and vibration effects at receptors closest to the construction site. However, during all works, a number of measures would be taken to minimise the amount of noise and vibration arising. This would include careful selection of modern and quiet plant and machinery, the erection of suitable hoardings around the construction site which would act as acoustic screens, adherence to specified noise and vibration action levels and working hours which would be agreed with WCC. All such mitigation would form part of the Site-specific EMP.

As described above in the discussions of transportation and access and air quality, deconstruction and construction generated traffic is not anticipated to significantly add to local traffic flows. As a result, noise and vibration arising from deconstruction and construction traffic would be insignificant.

The Development would be designed to stringent acoustic design targets derived from relevant guidance documents and WCC’s own requirements. This would minimise noise resulting from the operation of building plant and services. In this respect, the Development would provide internal noise environments suitable for residential development.

On completion of the Development, the additional traffic generated would be unlikely to give rise to a perceivable increase in noise levels in and around the Site.

Servicing at basement level would avoid noise disruption to noise-sensitive residential units of the Development, along with those sensitive receptors identified within the surrounding area. There would be no servicing or waste collection undertaken on-street. However, a Delivery and Servicing Plan (DSP) would be implemented, containing measures to control delivery and service vehicle movements.

A combination of planning restrictions, licensing restrictions, lease agreements and tenant handbooks would minimise noise breakout from cafés, restaurants and drinking establishments associated with any noise generated by retail units.

13. ARCHAEOLOGY

An archaeological assessment has been undertaken, which involved the study of archive records and historical maps, and previous investigation works, in order to identify the archaeological potential of the Site.

The Site does not contain any nationally designated (protected) heritage assets, such as Scheduled Monuments (SMs), listed buildings or registered parks and gardens. The Site does not lie within a conservation area or an Archaeological Priority Area (APA).

Although previous development would have removed much of the archaeology, localised areas of the Site have a moderate to low potential to contain palaeoenvironmental remains. However, it is considered that localised palaeoenvironmental remains would be buried heritage assets of low importance.

The effects of the Development upon archaeology would be limited to those during the deconstruction and construction works, essentially from piling; removal of part of the existing basement slab and/ or ground floor slab; and implementation of the proposed ground source cooling system. Accordingly, targeted geo-archaeological sampling would be undertaken prior to construction. The results of the archaeological monitoring would, if necessary, enable an appropriate mitigation strategy to be drawn up, which would be agreed in consultation with WCC. The mitigation strategy would aim to ensure preservation by record and an enhanced understanding of any heritage assets encountered and their importance. This would be most likely achieved via an Archaeological Watching Brief during the intrusive works for buried heritage assets of limited importance and / or targeted archaeological excavation for buried heritage assets of at least moderate importance.


Page 17 of 20

14. GROUND CONDITIONS AND CONTAMINATION

A ground conditions and contamination assessment has been undertaken in order to establish the likely contamination risks posed to a number of receptors including construction site workers, future occupants of the Development, surface water resources, groundwater and fauna and flora. The assessment has used a range of information sources including a review of historical maps, geological maps, previous ground investigations undertaken for sites in the vicinity of the Site and information provided by the Environment Agency and other organisations, e.g. the London Fire Brigade - Petroleum Section.

It is concluded that the potential for significant ground contamination to be present on the Site is likely to be low, due to the extensive basement areas which are likely to have removed a large proportion of historical contamination.

Deconstruction and construction works would be subject to a range of mandatory legislative health and safety controls. These would prevent construction workers coming into direct contact with any potential contamination in the soil. Such controls would form part of the Site-specific EMP which would also include protective and preventative measures to ensure that contamination risks to underlying soils and groundwater would be reduced to a negligible level. In addition, the risk posed by unexploded ordnance would be minimised through education of the construction work force and the active presence of an Explosive Ordnance Disposal Engineer during all intrusive works undertaken in areas of medium to high unexploded ordnance risk.

Whilst limited, the choice of appropriate piling and foundation techniques would be agreed with the Environment Agency to prevent the mobilisation and release of potential contaminants to below ground water resources.

On completion of the Development, there would be negligible risks posed by contamination to future occupants, soil, groundwater and flora and fauna. This would be largely attributable to the remediation of any contamination found during deconstruction and construction. In addition, the entire area would be covered with hardstanding, which would serve to act as a physical barrier to any potential contamination source (the soil). Soft landscaped areas would be inherently removed from all ground contamination pathways and sources and new landscaping substrate would be clean and inert.

15. SURFACE WATER DRAINAGE AND FLOOD RISK

The effects of the Development upon water resources and drainage have been informed by a review of various information sources including those made available by the Environment Agency and Thames Water. A Flood Risk Assessment (FRA) has also been prepared to accompany the planning application and is included as part of the ES.

There are no surface water features on Sites, although a lake is located approximately 195m north-west of the Site within Buckingham Palace Gardens. The River Thames is located further afield, approximately 1km east and south of the Site. The Site is considered to be at low risk of flooding from the River Thames when the river’s flood defences are taken into account.

During the deconstruction and construction works, the Site-specific EMP would seek to ensure that groundwater beneath the Site would be protected from pollution. For example, construction site discharges would be passed through settlement and oil interceptor facilities where required. In addition, the use of an appropriate piling technique (refer to ‘Ground Conditions and Contamination’ section of this NTS) would ensure that contamination of the groundwater is prevented.

The existing basement of the below ground Site would be retained and incorporated into the Development. Given that the existing basement would not be extended vertically or laterally, shallow groundwater flows beneath and surrounding the Site is not expected to be significantly altered or displaced during deconstruction and construction and is therefore unlikely to have an effect on existing groundwater flows.

It is expected that, if installed, the geothermal heat pump would comprise two lined boreholes advanced to the Principal Aquifer of the Upper Chalk Formation, which underlies the Site. Since the boreholes would be relatively small and lined, there would be no risk of groundwater rising up the boreholes and flooding the basement.


Page 18 of 20

The Site is protected by flood defences and above the peak flood levels of the River Thames. As such, the risk of tidal and fluvial flooding during deconstruction and construction is very low. Additionally, there is a low risk of breach in the flood defences.

It is assumed that all works to the foul water drainage system would be undertaken in consultation and agreement with Thames Water. Such works would be subject to standard best practice and mandatory regulatory controls and would be designed to cope with the future population of Portland House. As such, there would be limited risks of foul water flooding during deconstruction, construction and operation of the Development.

The lowest ground floor finished floor levels of the Development would be above the statutory flood level of 5.02m AOD. This statutory flood level takes into account the existing River Thames flood defences and means that the Development would be adequately protected from river flooding.

The Development would reduce the amount of surface water run-off by increasing the amount of green roof on the raised and terraced amenity area of Cardinal Place; providing an additional area of soft landscaping immediately around Portland House; and providing an attenuation tank at ground level within Portland House to store 99m

3 of surface water runoff.

16. WIND

A desk-based review of the deconstruction and construction programme concludes that no unacceptable wind effects would be expected within and surrounding the Site during all works. Temporary removal of cladding would leave the existing surrounding buildings to the east of the Site temporarily a little more exposed to the prevailing winds, but it is anticipated to remain generally

acceptable for walking access. Consequently, as construction of the Development proceeds, the wind

conditions of the Site would gradually adjust to those of the Development.

Wind Tunnel Model

An assessment of the comfort and safety of the local wind microclimate within and surrounding the Site once the Development is completed and operational has been undertaken via wind tunnel


Page 19 of 20

testing. This utilised a scale model of the Development in the context of the ‘likely future baseline’ situation.

Taking into account the intended pedestrian usage of the Site and its immediate surrounds, the wind tunnel testing concluded that the local wind conditions at the majority of locations tested are predicted to be suitable and safe for use. Only three locations tested would benefit from local mitigation measures such as additional tree or shrub planting or wind screens. These locations are at the proposed main entrance to Portland House, the entrance to the Marks and Spencer’s retail unit located to the northeast of the proposed Portland House and at one retail unit along the southern façade of Cardinal Place (fronting Victoria Street). Such mitigation would ameliorate the marginal effects in these locations and would give rise to wind conditions suitable for entrance use (i.e. the mitigation would ensure that these locations would be subject to wind conditions which would be comfortable and safe for the intended pedestrian use). The details of such mitigation would be subject to subsequent detailed design.

17. DAYLIGHT, SUNLIGHT, OVERSHADOWING, LIGHT POLLUTION AND SOLAR GLARE

An assessment has been made of the likely effect of the Development on the daylight, sunlight, overshadowing, light pollution and solar glare on neighbouring occupiers of properties and amenity spaces near to the Site and also for new residential units and amenity spaces proposed within the Development.

During the deconstruction works, there are likely to be increasing short-term beneficial daylight and sunlight effects to the identified sensitive receptors as a result of the building being stripped back to the structural core, thereby reducing the current obstructions which influence the amount of daylight and sunlight reaching the sensitive receptors. The interim levels of daylight and sunlight and the reduction in overshadowing would be short term and temporary in nature.

The most notable effect that is likely to arise during the deconstruction and construction phases is light trespass from the temporary lighting units used on the construction site. This is because these lighting units are less likely to be shielded using lamp shades or window blinds etc. Consequently potential light trespass would be minimised by carefully considering the position / orientation of such lighting units so that the potential for light to be emitted directly away from the site is minimised.

With the completion of the proposed Portland House, the neighbouring properties of The Phoenix Public House and The View would continue to receive very similar levels of daylight and sunlight and would meet the BRE guidelines. At Buildings 7b/c of Victoria Circle, the Vertical Sky Component (VSC) results show that a number of the windows would experience ratio reductions beyond that recommended by the BRE guidelines. However, this is due to the fact that the windows are predicted to receive low VSC levels in the likely future baseline condition. Out of 149 windows assessed, 67 windows would experience a minor adverse effect. Of these, 40 windows serve bedrooms whilst the remainder (27 windows) serve living rooms, all of which have more than one window. In addition, of the 33 apartments assessed in Buildings 7b/c, the Average Daylight Factor (ADF) show that only eight units would experience reductions of daylight within bedrooms. Futher, all apartments would continue to receive adequate daylight to the main living room and at least one bedroom using the ADF test.

Overshadowing from the completed Development within the public amenity space of Cardinal Place is well within the recommendations set out by the BRE guidelines.

Within the Development itself, over 99% of the habitable rooms would enjoy good levels of daylight above those recommended by the BRE guidelines. This is considered a very good level of compliance, especially taking into consideration the urban location of the Site. In addition, the levels of sunlight that are likely to be enjoyed to the proposed apartments are acceptable for an inner city area considering the constraints of the Site. Where possible the layout of each flat has been designed to ensure the sunlight availability to each apartment has been maximised whilst ensuring an acceptable balance is kept with the other design factors.

The likelihood of solar glare occurring within the vicinity of the Site is low, due to the orientation of the roads and the configuration and heights of existing and proposed building. As the Development is of a similar height and orientation as the existing Portland House, the likelihood of solar glare occurring in the completed Development condition is considered similar to that identified in the baseline


Page 20 of 20

condition. Furthermore the proposed materials for the façade are not proposed to have a high reflectivity. There would also be no significant adverse effects from solar glare.

18. CUMULATIVE EFFECTS

Two types of cumulative effects have been assessed in relation to the Development:

The interaction of individual effects from the Development upon a set of defined sensitive receptors. For example, noise, dust and visual intrusion; and

The combined effects arising from other reasonably foreseeable schemes.

The ES considered the cumulative effects of the proposals for the following:

The deconstruction and construction of the Development in isolation would result in some temporary adverse combined effects. These would be predominantly associated with dust, noise, vibration and townscape and visual effects. The site-specific EMP would ameliorate these construction related effects as far as possible.

Despite the above, there would also be short term beneficial cumulative effects experienced during the deconstruction and construction works, associated with improved daylight, sunlight and overshadowing.

The construction of the Development in conjunction with the construction of a number of other reasonably foreseeable schemes, were generally found to be minimal. Exceptions include cumulative beneficial effects in relation to socio-economic, due to the provision of housing within the Victoria area, townscape, conservation and visual effects and surface water and flood risk drainage as a result of providing attenuation to account for climate change.

portland house, bressenden place, london environmental ... · below ground, the site houses the...

Documents