Chelsea Embankment Foreshore

Home , Blackfriars Bridge, Chelsea Bridge, Chelsea Bridge Road, Chelsea Embankment, Embankment (earthworks), London sewerage system

Introduction 1

Royal Borough of Kensington and Chelsea and of Kensington Borough Royal Ranelagh to approximately 280,000m³ (equivalent 112 Olympic swimming pools) CSO site years. four Approximately Thames Tunnel Thames

Chelsea Embankment Chelsea Foreshore Foreshore CSO name: year: in an average CSO spill volume Site type: works: of main construction Duration authority: Local Key facts Key Currently, untreated sewage regularly overflows into the River Thames from London’s Victorian sewerage system sewerage Victorian London’s from Thames into the River overflows regularly sewage untreated Currently, the through overflows these would intercept Tunnel Thames (CSOs). The proposed overflows sewer via combined Station. The Mills Pumping London and Abbey link west tunnel, which would and transfer storage use of a new reduction Tunnel. The Works via the Lee Treatment to Beckton Sewage would then be transferred flow sewage users of and for the environment benefits bring long-term Thames would entering the River sewage in untreated and this document need a number of sites along the route we the project to deliver Thames. In order the River Foreshore. sites at Chelsea Embankment preferred identifies our current

Site information paper Chelsea Embankment Foreshore

Section 1: Introduction and site information We are proposing to use the foreshore of the River The two construction sites required for the works at Thames, opposite the Bull Ring Gates of the Royal Chelsea Embankment Foreshore are shown in Figure Hospital Chelsea, a section of Chelsea Embankment 1A. The main site is located in the foreshore of the River (A3212) and part of the grounds of the Royal Thames, with part of the site extending north onto the Hospital Chelsea for this construction work and to Chelsea Embankment (A3212), along which the Thames accommodate permanent structures required to Path is located and the south eastern part of the operate the main tunnel. grounds of the Royal Hospital Chelsea. The site is also within the Thames Conservation Area. To the east of the The sites would be used to intercept the existing local main site is Chelsea Bridge. Ranelagh Gardens and the CSO, known as the Ranelagh CSO and to construct a Royal Hospital Chelsea, (together a Grade II registered connection to the northern Low Level Sewer No.1 to park and garden), lie to the north of the main site, divert flows to the main tunnel. separated from it by Chelsea Embankment (A3212).

These works, along with our works at Blackfriars Bridge The smaller site, which is required to connect the Foreshore and Victoria Embankment Foreshore mean northern Low Level Sewer No.1 to the main tunnel, is that we do not need additional sites to intercept the located within the eastbound carriageway and footpath following CSOs along the northern embankment: of the Chelsea Embankment (A3212) and the southern Smith Street, Queen Street, Church Street, Grosvenor part of Ranelagh Gardens. Ditch, Kings Scholars Pond, Western Pumping Station, Northumberland Street, Savoy Street, Norfolk Street This site information paper sets out our proposals at and Essex Street. Chelsea Embankment Foreshore. We have also produced project information papers, which cover overarching topics relating to the project. Where we consider that a project information paper is particularly relevant, we Related documents: have highlighted this in a related documents box. At the end of this site information paper is a list of other Build documents, which may be of interest and a glossary of terms.

2 Introduction

Draft limit of land to be Chelsea Bridge Road acquired or used Proposed tunnel route – centreline Local authority boundary KENSINGTON & Ranelagh Existing sewer CHELSEA Gardens Existing CSO

Royal Hospital Chelsea (South Grounds)

Tite Street CITY OF WESTMINSTER

Chelsea Embankment Chelsea Grosvenor Bridge Bridge Ranelagh CSO Low Level Sewer No.1

WANDSWORTH N

Figure 1A: Chelsea Embankment Foreshore location plan

3 Chelsea Embankment Foreshore

How we chose this site

What we proposed at phase one consultation At phase on consultation, which was held between Discussions have also been held with English Heritage, September 2010 and January 2011, we presented who raised issues about the effect of the permanent Chelsea Embankment Foreshore (west of Chelsea Bridge) structures on views of the river wall along the River as our preferred site to intercept the Ranelagh CSO and to Thames. As a result we have re-assessed sites inland and connect the northern Low Level Sewer No.1 to the main concluded that Ranelagh Gardens could potentially meet tunnel. Due to the constrained nature of the area, no our requirements. other suitable sites were identified. What we are proposing at phase two consultation Why we have amended our proposals We have identified three shortlisted sites to intercept the Since January 2011 we have considered the comments CSO, as shown on Figure 1B. The sites are: from phase one consultation, feedback from ongoing engagement and new information; and undertaken • Chelsea Embankment Foreshore further technical work. This has resulted in us re-assessing (west of Chelsea Bridge) (site 1) potential sites to intercept the Ranelagh CSO and to • Ranelagh Gardens (site 2) connect the northern Low Level Sewer No.1 to the main tunnel. • Chelsea Embankment Foreshore (opposite to Bull Ring Gate) (our preferred site). Our findings have confirmed that the best location to connect to the northern Low Level Sewer No.1 to the main tunnel is within the existing eastbound carriageway of Chelsea Embankment (A3212).

Engagement with Crossrail has revealed that a smaller site located within the safeguarded zone for Crossrail 2 would be acceptable. Therefore, Chelsea Embankment Foreshore (opposite to Bull Ring Gate) is a possible site.

4 Introduction

Preferred site – Chelsea Embankment Foreshore (opposite Bull Ring Gate) Other shortlisted Chelsea Bridge Road site locations Local authority boundary KENSINGTON & CHELSEA Ranelagh Gardens CITY OF Royal Hospital WESTMINSTER Chelsea (South Grounds) Site 2

Site 1

Chelsea Embankment

WANDSWORTH

Figure 1B: Preferred and shortlisted sites

5 Chelsea Embankment Foreshore

Chelsea Embankment Foreshore (opposite to Bull Ring Gate) is our preferred site to intercept the Ranelagh CSO. The site would have less effect on the foreshore of Related documents: the River Thames because it is only necessary to build one structure. There is also likely to be less effect on local Q&A Consultation residential areas. The location of the site also offers the opportunity to create a new area of public space that complements the setting of the historic environment and Site selection views along the River Thames.

The northern Low Level Sewer No.1 connection would be constructed within the existing eastbound carriageway of Chelsea Embankment (A3212). These works would be in the same location for each of the shortlisted sites.

Site 1 – Chelsea Embankment Foreshore (west of Chelsea Bridge) is a shortlisted site. We consider this site to be less suitable than our preferred site because it requires two structures to be built within the foreshore of the River Thames to accommodate the drop shaft and interception chamber. This would require a larger working area, and the permanent structures would have a greater effect on the historic environment, foreshore and views along the River Thames.

Site 2 – Ranelagh Gardens is a shortlisted site that is considered to be less suitable than our preferred site because it is closer to the Lister Hospital and residential areas; it would result in a loss of open space, disrupt visitors to Ranelagh Gardens and would potentially affect events such as the Chelsea Flower Show. Whilst the permanent works would be less visible within the Gardens than in our preferred foreshore site, we do not consider that this benefit outweighs the issues set out above.

6 Construction

Section 2: Construction Construction activities Construction activities are required to intercept the CSO and short connection tunnel to the main tunnel. Figure and to link the northern Low Level Sewer No.1 to the main 2A illustrates the below ground infrastructure proposed. tunnel. We would construct an interception chamber to As the construction works would take place within the intercept the CSO. A connection culvert would link the foreshore of the River Thames, a permanent structure interception chamber to a drop shaft (approximately extending into the foreshore is required. These activities 45m deep) through which flows would pass down to a would take place within the area indicated by the red line short connection tunnel. This would then join to the main in Figure 1A, in five main phases, lasting approximately tunnel. We would also construct an overflow weir chamber four years in total. The main construction activities which would allow flows to be transferred from the associated with these phases are set out in Table 2.1. northern Low Level Sewer No.1 down the same drop shaft Existing Low Level Sewer No.1 Existing overflow sewer Construction

Overflow weir chamber

Drop shaft Valve chamber

Short connection tunnel Existing Interception overflow to chamber River Thames

Main tunnel

Figure 2A: Illustration showing typical elements of below ground infrastructure

7 Chelsea Embankment Foreshore

Phase 1 Site setup Advance works

Table 2.1: Main activities during construction phases Figure reference – Figure 2C Typical working hours Varies Standard Utilities connected ü Utilities diverted or protected ü Site cleared ü Temporary works in the River Thames constructed ü Site facilities and access set up ü Drop shaft excavated and built Short connection tunnel excavated and built Above and below ground structures constructed Mechanical and electrical equipment installed

Main construction activities Main construction Temporary works in the River Thames removed Site restored and landscaped Temporary site facilities removed

Our typical working hours are expected to be: Standard: 8am-6pm weekdays, 8am-1pm Saturday* Extended standard: 6pm-10pm weekdays, 1pm-5pm Saturdays Continuous: 24 hours a day, seven days a week** Varies: Working hours for advanced works will depend on the nature of the works and will be agreed with the local authority

* Standard working hours would also include, subject to agreement with the local authority: – a short period (up to one hour) before works start and after they have finished to allow our workers to prepare for work and check the site. – equipment and machinery maintenance could also take place 1pm-5pm Saturday and 10am-4pm Sunday. ** The main activities taking place 24 hours a day are below ground or within an enclosure.

8 Construction

Phase 2 Phase 3 Phase 4 Phase 5 Drop shaft Tunnelling Construction of Completion of construction other structures works and site restoration

Figure 2D Figure 2D Figure 2E – Standard Continuous Standard Standard

ü ü ü ü ü ü ü

Related documents:

Build

Managing construction

9 Chelsea Embankment Foreshore

Site layout and construction phases Figures 2C, 2D and 2E show how the site might be laid • The proposed construction access arrangements out during the construction phases, which are set out maintain two-way traffic along Chelsea Embankment in Table 2.1 and Figure 2B. These layouts have been (A3212) by reducing road lane widths. This minimises informed by the size of the infrastructure proposed, the effects on traffic congestion. the construction methods required and the location • The access route to the site has been selected to of neighbouring buildings and structures. They have minimise tree loss by using an existing gap in the line also been developed to minimise effects on the local of trees for one of the accesses. This minimises the community and environment. Particular factors at this site potential effects on local ecology and landscape. that have influenced the layout are as follows: The site layouts are indicative only, and the contractor • Since phase one consultation, the number of structures may arrange the site in a different way, depending on in the River Thames at this location has been reduced the chosen construction methods, provided that any from two to one. This has been achieved because we environmental effects are appropriately managed, and can now intercept the Ranelagh CSO directly following that the main construction activities are undertaken further discussions with the Crossrail 2 project team within the red line shown in Figure 1A. regarding their safeguarded area. This reduces the potential effects on river ecology, river flows and river navigation.

Year 1 Year 2 Year 3 Year 4

Advance Advance works P1 P3 P5 P2 P4

Figure 2B: Construction timeline showing approximate duration of works in phases (P)

10 Construction

KENSINGTON & Two-way CHELSEA traffic flow

Two-way traffic flow Diversion rejoins Thames Path at pedestrian crossing at Tite Street

Maximum extent of construction sites for phase 1 Site hoarding/traffic barrier Cofferdam Barge Local authority boundary Traffic lane coned off for site access Site access Jack up barge servicing Existing Thames Path WANDSWORTH piling operations Thames Path diversion N

Figure 2C: Illustrative phase 1 construction plan

11 Chelsea Embankment Foreshore

Maximum extent of construction site for phases KENSINGTON & 2 and 3 CHELSEA Site hoarding/traffic barrier Cofferdam Two-way traffic flow Local authority boundary Diversion rejoins Thames Site support/welfare Path at pedestrian crossing at Tite Street Excavated material storage and processing Maintenance workshop and storage Construction support Internal site road

Drop shaft Traffic lane coned off for site access Cranes Option for contractor Site access to transport materials using barges Existing Thames Path Thames Path diversion

WANDSWORTH N

Figure 2D: Illustrative phases 2 and 3 construction plan

12 Construction

KENSINGTON & Maximum extent of CHELSEA construction sites for phase 4 Piling rig Site hoarding/traffic barrier Diversion rejoins Thames Path at Cofferdam pedestrian crossing at Tite Street Local authority boundary Two-way Site support/welfare traffic flow Excavated material storage and processing Crane Maintenance workshop and storage Two-way traffic flow Traffic lane coned off for site access Site access Drop shaft Existing Thames Path Thames Path diversion Cranes Option for contractor to transport materials using barges

WANDSWORTH N

Figure 2E: Illustrative phase 4 construction plan

13 Chelsea Embankment Foreshore

Additional works and activities The main construction activities at this site are set out in Table 2.1. We would also need to undertake additional works and activities, some of which may be located outside of the area indicated by the red line in Figure 1A. The anticipated additional works and activities are set out in Table 2.2.

When Type of works What we would do Installation of equipment to monitor The locations of monitoring equipment would be agreed with the local environmental matters authority and relevant landowners. such as noise, vibration and dust. We would undertake studies to identify any effects our construction work Protection works to may have on third party structures. The studies may recommend particular third party structures construction methods or, in very limited instances, protection works. Required for (such as buildings, construction bridges and tunnels). If protection works are required to the existing sewer, we would access the phase sewer network through existing manholes. The works to connect to the northern Low Level Sewer No.1 would require the diversion of a gas main, electricity and telecoms cables from Chelsea Embankment (A3212) into the edge of Ranelagh Gardens. These diversion works would require the dismantling of a section of the Ranelagh Gardens Diversion of utilities. boundary wall/fence. The diversions would have to be carried out ahead of the main works, and would require lane closures and traffic management along Chelsea Embankment (A3212). The wall/fence and associated planting would be reinstated on completion of construction works.

14 Construction

When Type of works What we would do Temporary connection to utilities (such as We expect to connect to utilities in Chelsea Embankment (A3212) or water, sewer, phone Chelsea Bridge Road (A3216). and electricity supply). Required for construction Traffic management These may need to extend beyond our site and could include relocating phase works. kerb lines, repainting road lines and modifying traffic signals. There is a possibility that as the detailed design is developed we may need Dredging. to undertake dredging to allow barges to get to and from our site. Protection of river bed. We may need to carry out works to strengthen the river bed to avoid scour. Permanent connection Required for to utilities (such as We expect to connect to utilities in Chelsea Embankment (A3212) or operational water, phone and Chelsea Bridge Road (A3216). phase electricity supply) for the operational tunnel. Table 2.2: Additional works and activities

15 Chelsea Embankment Foreshore

Construction transport and access We propose to use barges to bring in and take away Table 2.3 sets out the anticipated average daily number material used to fill the cofferdam. It is not generally of lorries and barges visiting (ie travelling to and from) practical and cost effective to transport all materials the site during the peak months of each phase, based on to and from the site by barge so we would still need to moving cofferdam fill material by barge. transport some materials by road. We would however give the contractor the flexibility to determine the most practical and cost-effective means of transporting other materials and equipment.

Each barge would remove approximately 55 lorries from Related documents: the road. Using barges at this site would reduce the number of lorry visits to/from this site by approximately Transport 45% (saving 7,000 lorry visits over the construction period of approximately four years).

Phase 1 Phase 2 Phase 3 Phase 4 Phase 5 Site setup Drop shaft Tunnelling Construction Completion of construction of other works and site structures restoration

Average daily 16 lorries 17 lorries 7 lorries 33 lorries 12 lorries lorry visits

Average daily 2 barges none none none 2 barges barge visits

Table 2.3: Average daily lorry and barge visits during the peak months

16 Construction

Construction traffic would access the site by travelling west along Chelsea Embankment (A3212) and turning left into the site through a new entrance. The site access points are shown on Figures 2C, 2D, and 2E. Traffic leaving the site would turn left from the new entrance onto Chelsea Embankment (A3212) and continue westbound. Beyond this, construction traffic would use the major road network to get to and from its final destination.

During phases 1, 2 and 3 of the construction we would need to close part of the westbound carriageway of Chelsea Embankment (A3212) to establish the main shaft construction site and during phases 1 and 4 we would also need to close part of the eastbound carriageway of Chelsea Embankment (A3212) to undertake utility diversions (phase 1) and construct the interception chamber (phase 4). We would in each case reduce the width of the traffic lanes so that one lane in each direction would remain open. The Thames Path runs through our construction site; we would create a temporary signposted diversion for the duration of our works by using existing pedestrian crossings as indicated on Figures 2C, 2D and 2E. Based on our current design we do not anticipate that any bus stop relocations, parking bay suspensions or junction changes would be required.

17 Chelsea Embankment Foreshore

Management of construction works Our construction works would be managed in accordance with an agreed Code of construction practice (CoCP). For phase two consultation, we have produced a draft Related documents: CoCP Part A: General requirements, informed by CoCPs from other major construction projects in London and consultation with the local authorities. Through the Environment environmental impact assessment process, scheme- wide principles to address potential effects on the local environment have been identified and integrated into Managing construction the design. The CoCP Part A sets out scheme-wide control measures that would be used to minimise potential effects during the construction process. Transport

Table 2.4 sets out what we consider to be the key issues for this site during construction, and how we are currently proposing to address them.

Issue Our response Since phase one consultation, the construction site access has been moved Potential loss of and damage to trees further west. This minimises tree loss by using an existing gap in the line of along Chelsea Embankment (A3212) to trees for one of the accesses. Potential damage to trees during construction facilitate site access and construction. would be further minimised through careful root protection, pollarding and trimming methods.

Possible effect of construction vehicles We have sought to minimise disruption to the local road network through on the volume of traffic on Chelsea our site layout and design. During construction phases 1 and 4, two-way Embankment (A3212) and Chelsea traffic along Chelsea Embankment (A3212) would be maintained by Bridge Road (A3216), particularly when reducing the width of the traffic lanes. they coincide with events such as the We would manage the effects of road transport through our traffic Chelsea Flower Show. During phases 1 management plans, which will seek to limit the number of vehicle and 4 of construction, we would need to movements and hours of operation, identify the most suitable site access close part of the eastbound carriageway points and any necessary highway management arrangements – including of Chelsea Embankment (A3212). during Chelsea Flower show and other events.

The Thames Path would be temporarily diverted a short distance via a safe Temporary diversion of the Thames Path alternative route along the side of Chelsea Embankment (A3212). Existing and cycleway. pedestrian crossings would be used.

18 Construction

Issue Our response

The contractor would be required to implement noise and vibration control Possible effect of noise and vibration on measures at the worksite, which will be set out in the CoCP. Continuous neighbouring areas. tunnelling would only be undertaken for a short period of time to construct a connection tunnel from the drop shaft to the main tunnel.

Preliminary findings indicate that while there is the potential for dust The effects of air pollution and dust in nuisance effects, there are unlikely to be any significant local air quality neighbouring areas. effects at any of the sites. The contractor would put in place air and dust control measures at the worksite, which will be set out in the CoCP.

Since phase one consultation, we have reduced the size of the cofferdam Possible effects of construction activities structure to limit encroachment into the River Thames and effects on on local wildlife, including Ranelagh Ranelagh Gardens. Ecological surveys are also being undertaken to identify Gardens, foreshore habitat and river possible effects arising from construction activities. The contractor would wildlife. put in place various control measures at the worksite to minimise these effects as far as possible. These will be set out in the CoCP.

Table 2.4: Key issues relating to construction

19 Chelsea Embankment Foreshore

Section 3: Future use

This section describes the site after the completion of the • Underground structures with ground level access covers construction work, ie when the main tunnel is in use – the including: a CSO drop shaft with an internal diameter ‘operational phase’. of approximately 12m, connection tunnel to the main tunnel, connection culvert, interception chamber, valve chamber, passive filter chamber and an overflow weir Design chamber to divert flow from the northern Low Level Since our phase one consultation we have progressed Sewer No.1 under Chelsea Embankment (A3212). the design for the permanent use and appearance of • Two main ventilation columns up to 6m high. the structures at Chelsea Embankment Foreshore. The design of the permanent proposals follows our scheme- • Two small diameter ventilation columns to the wide principles and takes into account comments made interception chamber up to 6m high. and ongoing engagement with the Royal Borough of • Maintenance vehicle access. Kensington and Chelsea and other technical consultees. • Two electrical and control kiosks. Our permanent works which are formed within a structure Table 3.1 sets out the site specific issues that have extending into the foreshore of the River Thames need to influenced our permanent design proposals and how we incorporate functional elements, which are required for have addressed them in our proposed design. the operation of the tunnel. These include:

Issue Our response

The footprint of the structures we are placing in the River Thames is determined by their functional requirements. The drop shaft has reduced in diameter since our phase one consultation as a result of more detailed design.

Our proposals for the permanent layout and design of the site have sought to reduce the Loss of foreshore extent of the permanent works within the foreshore of the River Thames to minimise effects habitat and effects on on water ecology as far as possible. ecology within the River Thames. Ecological surveys of the River Thames and foreshore are being undertaken to identify possible effects, and design measures would be incorporated where required.

Construction of the tunnel would also deliver river wide improvements to local water quality, which would result in positive effects on river ecology, including habitat improvements and reduced fish kills.

20 Future use Future use Future Our response 21 A suitable landscape design is being developed to restore the site following completion of completion following site the restore to developed design is being landscape A suitable Gardens. and Ranelagh of the Embankment the setting reflect and the works during lost trees replace to on the Embankment trees new design also includes The the Royal to the south grounds through views allow to be located would These construction. Chelsea. Hospital the opposite located chamber interception an our design showed consultation, phase one At culvert a connection by connected Chelsea which was Hospital the Royal to Bull Ring Gates a provide to design has been amended Bridge. The Chelsea close to shaft located a drop to of the Bull Ring Gates. in front located Thames River in the single structure Thames, along the River views historic account into take proposals Our permanent design II listed Chelsea and Grade Hospital Royal I listed of the Grade including the setting Chelsea Bridge. marks which Monument Walk be aligned with would structure of the foreshore location The the south. One of the from Chelsea when viewed Hospital Royal axis of the the central and during our works be removed Embankment (A3212) would along Chelsea trees existing Hospital and the Royal Thames the River between open up views to in order not replaced further to be aligned either side of the structure kiosks would control proposed Chelsea. The the view. frame blend which would frontage a smooth curved provide has been designed to structure The view on the long sweeping the effect minimise to in order wall river the existing into would wall of the new materials proposed The in this location. Thames along the River those of the embankment. complement and a pedestrian link between a visual provide to seek design would landscape overall The the River Chelsea from Hospital the Royal to access and the historic structure the new Gardens, Ranelagh to wall/fencing including replacement In addition, landscaping Thames. to required of the site the restoration ensure to be provided planting and paving would and the bound carriageway the west No.1 within Sewer Level northern Low the intercept Gardens. of Ranelagh border Issue Effects on the setting on the setting Effects I listed of the Grade Chelsea, Hospital Royal Chelsea II listed Grade Bridge and Thames and Area Conservation along the views historic Thames. River Effect on the setting of on the Effect Gardens. Ranelagh Table 3.1: Site specific issues that have influenced our permanent design our influenced Site specific issues that have 3.1: Table Our response The footprint of the structures we are placing in the River Thames is determined by their by is determined Thames River placing in the are we of the structures footprint The our phase one since in diameter shaft has reduced drop The functional requirements. design. detailed of more as a result consultation the reduce sought to have and design of the site the permanent layout for Our proposals effects minimise to Thames of the River the foreshore within of the permanent works extent as possible. as far ecology on water identify to being undertaken are and foreshore Thames of the River surveys Ecological required. where be incorporated would design measures and possible effects, quality, water local to improvements wide river also deliver of the tunnel would Construction and improvements including habitat ecology, on river effects in positive result which would fish kills. reduced Issue Loss of foreshore Loss of foreshore on and effects habitat the River within ecology Thames. Chelsea Embankment Foreshore

Figures 3A, 3B, 3C and 3D show the current site and provide illustrations of our design proposals. Further Related documents: information on the development of our design can be found in the Design development report. Design

Figure 3A: Photo of the site – before the works

22 Future use

Figure 3B: Artist’s impression of the site – after the works are completed

23 Chelsea Embankment Foreshore

Figure 3C: Aerial view of the completed works

24 Future use

New paving Electrical and to Bull Ring control kiosks Ventilation column

Royal Hospital Chelsea (South Grounds)

New pedestrian central refuge

DRAFT IMAGE, PLACEHOLDER ONLY

image to follow Chelsea Embankment

Brick river wall with Reed terrace Ventilation Stone inlay Stone New Ranelagh Reed stone parapet columns marking bench CSO outlet terrace historic axis Figure 3D: Layout of site once construction works complete

25 Chelsea Embankment Foreshore

Operation and maintenance Management of operational effects Once the tunnel is operational, we would need access We have undertaken technical work, including stakeholder to the site occasionally for inspection and maintenance engagement, to assess and identify the key issues purposes. We expect to visit the site approximately associated with this site once it is operational. Table once every three to six months to carry out inspections 3.2 summarises these issues and how we are currently and maintenance of the ventilation and below ground proposing to address them. equipment. This is likely to involve a visit by staff in a small van, and may take several hours.

Once every ten years, we expect to carry out a major internal inspection of the tunnel and underground structures. This is likely to involve a small team of inspection staff, a small team of support crew and two mobile cranes to lower the team into the shaft. This is likely to take several days and would require temporary fencing around the shaft for safety and security while the inspection takes place.

We may also need to make visits to the site for unplanned maintenance or repairs, for example, if there is a blockage, or equipment failure. This may require the use of mobile cranes and vans.

Permanent vehicular access would be from Chelsea Embankment (A3212).

26 Future use

Issue Our response

Odour effects at this site are expected to be negligible because we have developed an Air management plan to minimise possible odour and air quality Possible odour effects during the effects arising from the operation of the tunnel. The technology we are proposing operation of the tunnel. to use at this site includes the use of passive below ground carbon filters that will remove possible odour before air leaves the ventilation equipment.

Permanent access would be required for maintenance and servicing purposes to the shaft and ventilation equipment. Any planned maintenance visits would Disturbance from future be undertaken during normal working hours and all visits managed to avoid maintenance access. disruption to local residents, businesses and users of affected public areas as far as possible. Table 3.2: Key issues relating to site operation