strategic sewer site assessment stage 3: site suitability ......strategic sewer site assessment...

Protecting residents from flooding

Strategic Sewer Site Assessment Stage 3: Site Suitability Report: SS044 St Paul’s Gardens

Document Number C680-AH-00509-RP

November 2014

Counters Creek Strategic Sewer Flood Alleviation Scheme

Counters Creek Strategic Storm Relief Sewer/ Site Selection Methodology/ Stage 3/ SS044 SSR: November Document Number: C680-AH-00509-RP

COUNTERS CREEK STRATEGIC FLOOD ALLEVIATION SCHEME

STRATEGIC SEWER SITE ASSESSMENT STAGE 3: SITE SUITABILITY REPORT: SS044 ST PAUL’S GARDENS

Document Ref C680-AH-00509-RP Status Issued Document Type Report Title/Subject Strategic Sewer Site Assessment Stage 3: SSR Project Counters Creek Strategic Flood Alleviation Scheme Authors TWUL / Adams Hendry / Bruton Knowles / London Bridge

Associates / Mott MacDonald / URS Keywords St Paul’s Gardens Site Suitability Report

REQUIRED APPROVALS

Co-ordinator Reviewer Approver

Chris Colloff Associate, Savills

Mark Mathews

Town Planning Manager, TWUL

Martin Bennett

Project Lead, TWUL

Date 7/11/14 Date 7/11/14 Date 7/11/14

Counters Creek Strategic Storm Relief Sewer/ Site Selection Methodology/ Stage 3/ SS044 SSR: November 2014 Document Number: C680-AH-00509-RP

COUNTERS CREEK STRATEGIC FLOOD ALLEVIATION SCHEME

STRATEGIC SEWER SITE ASSESSMENT STAGE 3: SITE SUITABILITY REPORT: SS044 ST PAUL’S GARDENS

LIST OF CONTENTS

PAGE 0 EXECUTIVE SUMMARY 1 1 INTRODUCTION 2

1.1 PURPOSE OF THIS REPORT 2

1.2 STRUCTURE OF THIS REPORT 3

2 SITE INFORMATION 4 2.1 SITE AND SURROUNDINGS 4

3 PROPOSED USE OF SITE – CONSTRUCTION PHASE 5 3.1 CONSTRUCTION REQUIREMENTS 5

3.2 CONSTRUCTION PROGRAMME 5

3.3 CONSTRUCTION WORKING HOURS 6

3.4 ACCESS AND MATERIAL MOVEMENTS 6

3.5 CONSTRUCTION METHODOLOGY AND ASSOCIATED DIMENSIONS 7

4 PROPOSED USE OF SITE – OPERATIONAL PHASE 10 4.1 PERMANENT INSTALLATIONS 10

4.2 OPERATIONAL REQUIREMENTS 10

4.3 RESTORATION AND AFTER-USE 10

5 ENGINEERING ASSESSMENT 12 5.1 CONSTRUCTION TRAFFIC 12

5.2 CONSTRUCTION WORK CONSIDERATIONS 12

5.3 PERMANENT WORKS CONSIDERATIONS 12

5.4 HEALTH AND SAFETY 12

5.5 SUMMARY 12

6 PLANNING ASSESSMENT 13 6.1 INTRODUCTION 13

6.2 PLANNING APPLICATION AND PERMISSIONS 13

6.3 PLANNING POLICY 13

7 ENVIRONMENTAL ASSESSMENT 16 7.1 INTRODUCTION 16

7.2 TRANSPORT 16

7.3 NOISE 16


7.4 WATER RESOURCES - HYDROGEOLOGY 16

7.5 WATER RESOURCES – SURFACE WATER AND FLOOD RISK 17

7.6 AIR QUALITY 17

7.7 ARCHAEOLOGY 17

7.8 BUILT HERITAGE 17

7.9 TOWNSCAPE AND VIEWS 18

7.10 ECOLOGY 18

7.11 LAND QUALITY 18

7.12 CUMULATIVE EFFECTS 18

8 SOCIO-ECONOMIC AND COMMUNITY ASSESSMENT 20 8.1 SOCIO-ECONOMIC PROFILE 20

8.2 ISSUES AND IMPACTS 20

8.3 POTENTIAL INTEREST GROUPS 20

8.4 SUMMARY 21

9 PROPERTY ASSESSMENT 22 9.1 INTRODUCTION 22

9.2 CROWN LAND AND SPECIAL LAND COMMENTS 22

9.3 LAND TO BE ACQUIRED 22

9.4 ASSOCIATED PROPERTY COSTS TO PROJECT 22

9.5 COMPENSATION 22

9.6 SUMMARY 22

10 CONCLUSION 23 10.1 ENGINEERING 23

10.2 PLANNING 23

10.3 ENVIRONMENT 23

10.4 SOCIO-ECONOMIC AND COMMUNITY 24

10.5 PROPERTY 24

10.6 RECOMMENDATION 24

APPENDIX 1 BACKGROUND INFORMATION

APPENDIX 2 SITE LOCATION PLAN

APPENDIX 3 INDICATIVE CONSTRUCTION LAYOUT PLANS

APPENDIX 4 INDICATIVE OPERATIONAL LAYOUT PLANS

APPENDIX 5 PLANNING AND ENVIRONMENT PLANS

APPENDIX 6 RELEVANT PLANNING POLICY

APPENDIX 7 ENVIRONMENTAL APPRAISAL TABLES

Strategic Sewer Stage 3 Site Suitability Report: SS044 St Pauls Gardens


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0 EXECUTIVE SUMMARY 0.1.1 The Counters Creek Strategic Flood Alleviation Scheme is required to protect

properties from basement flooding within the Counters Creek catchment in the London Borough of Hammersmith and Fulham and the Royal Borough of Kensington and Chelsea. The present Counters Creek Flooding Register1 shows that over 1,700 properties are subject to flooding.

0.1.2 A number of strategic solutions are being pursued, each of which plays a role in

providing the relief necessary to guard against basement flooding. The strategic solutions comprise the provision of Flooding Local Improvement Projects (FLIPS), the introduction of pilot Sustainable Drainage Systems (SuDS) schemes, the implementation of sewer upgrade works and the construction of a strategic storm relief sewer (the ‘strategic sewer’ or ‘the scheme’).

0.1.3 This report relates to the further assessment of sites which have been identified as

being potentially suitable for development as part of the delivery of the strategic sewer in accordance with the Counters Creek Strategic Sewer Site Selection Methodology Report (Document reference C680-AH-00504-RP). Those shortlisted sites, identified through the Stage 3 Site Selection shortlisting process, have been individually subjected to further assess the feasibility of their potential use as part of the scheme. The individual site assessments are documented in a series of Site Suitability Reports (SSRs). In total 12 SSRs have been prepared.

0.1.4 This SSR relates to site SS044 located at St Paul’s Gardens, Hammersmith Road

in the London Borough of Hammersmith and Fulham. The purpose of this report is to provide a strategic assessment of the opportunities and constraints associated with using this site to construct a drive site to launch the Tunnel Boring Machine (TBM) to construction the tunnel.

0.1.5 The site is only considered to be suitable for the proposed use from a property

perspective, with all other assessments identifying the site as being less suitable. No assessment identified the site as unsuitable.

0.1.6 Given this outcome it is concluded that the site is less suitable. However, as there

are other identified alternative drive site exist which have been assessed as being more readily capable of accommodating the proposed use, the site is held in reserve and will not be considered further unless those alternative sites are unavailable.

1 The Counters Creek flood register is a register of all the properties in the Counters Creek Catchment that have been recorded as being flooded at some point in the past. This register is taken from the Thames Water Sewer Flooding History Database (SFHD). Properties are added to the register based on reported flooding incidents. Incidents are assessed to confirm whether or not the flood event was caused by an operational problem (i.e. a blockage), an extreme rainfall occurrence (greater than the current design criteria), or by a lack of capacity in the sewer.



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1 INTRODUCTION 1.1 Purpose of this report 1.1.1 The purpose of this report is to provide a strategic assessment of the suitability of

Strategic Site SS044 St Paul’s Gardens as a construction site for the Counters Creek strategic sewer (the ‘strategic sewer’ or ‘the scheme’), which forms part of the Counters Creek Flood Alleviation Scheme. The wider background to the scheme is provided in Appendix 1 to this report.

1.1.2 This report assesses the potential to use the site to construct a drive shaft to

launch the TBM to construct the strategic sewer. Section 2 of this report describes the site and its surroundings whilst Sections 3 and 4 of this report provide details on the proposed use of the sites during the construction and operational phase.

1.1.3 This report forms part of the site and options assessment process that has been

undertaken by the Counters Creek team to identify preferred sites for drive shafts, reception and interception shafts, a storm outfall and a pumping station, which are required to deliver a new storm relief sewer. Sites are also potentially required for construction compounds if insufficient space is available at individual construction sites.

1.1.4 The St Paul’s Gardens site was identified as a potential site for development

during the longlist (Stage 2) site assessment process. Following further assessment as part of the shortlist (Stage 3) site assessment process it was concluded that the site warranted further testing through this Site Suitability Report (SSR) as to its suitability for use as a drive site. Further detail regarding the site selection methodology can be found in the Strategic Sewer Site Selection Methodology Report (Document reference C680-AH-00504-RP), which is summarised in Appendix 1 to this report.

1.1.5 This report assesses the suitability of the St Paul’s Gardens site in respect of the

proposed use, considering engineering issues, planning issues, potential environmental, noise and transport effects, community issues and property matters. In brief, the suitability of the site will be considered in the following way: • Suitable: the site is expected to experience minimal constraint or conflict

with the surrounding environment, or encounter minimal constraints in respect of existing conditions at the site, although there may be a requirement for some form of compromise, mitigation and compensation.

• Less Suitable: the site is considered to experience constraints or conflicts with the surrounding environment, or encounter constraints in respect of existing conditions at the site, which will require mitigation and compensation and are anticipated to affect the design and use of the site. It may be necessary to consider the use of this site alongside the availability of alternative locations.

• Unsuitable: the site is considered to experience substantial constraints or conflicts with the surrounding environment, or encounter considerable constraints in respect of existing conditions at the site, which are unlikely to be capable of being mitigated or compensated. An alternative site(s) should be sought.

1.1.6 These individual assessments then enable an overall judgement to be made,

having regard to all engineering, planning, environment, transport and property



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issues, whether the site is suitable for the intended use. That overall assessment will also identify any issues where further investigation or mitigation measures may need to be considered and addressed.

1.1.7 After the completion of the SSRs, the final outcome of Stage 3 of the site assessment process is for a preferred route option and associated sites to be identified.

1.1.8 These will be reported through the Phase 1 public consultation process and

feedback from the consultation process will be used to update and revisit preferred route and site outcomes, where necessary. Any updates to the sites recommended for inclusion as preferred sites will then be considered against engineering, planning, environment, noise, transport and property issues.

1.2 Structure of this Report 1.2.1 The report is structured as follows:

• Section 2 – site information: This section provides general information that relates to the site, as the basis for the assessment that follows.

• Section 3 – proposed use of the site – construction phase: This section provides an explanation of how the site would be used during the construction phase if selected, identifying any assumptions that have been made.

• Section 4 – proposed use of the site – operational phase: This section provides an explanation of how the site would be used during the operational phase if selected, identifying any assumptions that have been made.

• Section 5 – engineering assessment: This section provides an engineering assessment based on the information in Sections 2, 3 and 4, identifying any assumptions that have been made.

• Section 6 – planning assessment: This section provides a planning assessment of the site and its relationship with relevant planning applications and permissions and with relevant planning policies and designations.

• Section 7 – environmental appraisals: This section provides an appraisal of specific environmental topics relevant to the site. An appraisal of potential impacts is provided, along with the identification of potential mitigation measures that may be required. This is based on professional judgement, site investigations and the plans and assumptions included in this SSR.

• Section 8 – socio-economic assessment: This section provides a socio-economic assessment, including consideration of potential community impacts and issues. This is based on professional judgement, site investigations and the plans and assumptions included in this SSR.

• Section 9 – property assessment: This section provides a property assessment that includes landownership, land acquisition processes, acquisition risks, and the potential for compensation events.

• Section 10 – conclusions: This section provides conclusions for each of the assessments, together with the overall assessment of the suitability of the site.



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2 SITE INFORMATION 2.1 Site and surroundings 2.1.1 The site is located on Hammersmith Road (A315) within the administrative

boundary of the London Borough of Hammersmith and Fulham (LBH&F). It comprises St Paul’s Garden, an area of designated open space. A commemorative plaque, erected on the gates to the gardens by the ‘Hammersmith and Fulham Historic Building Ground’ is to commemorate the location where the presentation of the final invasion plan for the D-Day Normandy landings was held. A site location plan is attached at Appendix 2.

2.1.2 Immediately to the east of the site is 153 Hammersmith Road, which is occupied

by a Grade II listed building (Masters Lodge and Porters Lodge of St Paul’s School). This building has been converted into a 35 bed hotel and offers views into St Paul’s Garden and open space. The redbrick wall and railings that enclose 153 Hammersmith Road and St Paul’s Garden and open space are also Grade II listed, along with the small circular red brick building positioned along the eastern boundary of the gardens.

2.1.3 Beyond 153 Hammersmith Road to the east is a serviced office block and a church

with grounds that extend to the boundary of St Paul’s Garden and open space. Immediately to the south of the site, along More Close / Lily Close and to the east of the site along Colet Gardens are residential properties. Opposite the site along Hammersmith Road are office buildings.

2.1.4 Hammersmith Road, a Borough Distributor Road, has two-lanes of traffic in each

direction. The site can be accessed through the existing access along Hammersmith Road, which consists of metal gates and a drop curb. Adjacent to the entrance to St Paul’s Garden and open space along Hammersmith Road is a bus stop.

2.1.5 An indicative construction layout option is provided in Appendix 3. Based on an

initial construction layout, the nearest residential properties are the properties to the south of the site off More Close / Lily Close. These properties are located within 100m of the construction site. Once operational access to retained infrastructure at the site would be required, as shown on site layouts in Appendix 4.

2.1.6 The site is covered by various planning and environmental designation in the

London Borough of Hammersmith and Fulham Core Strategy (October 2011). All the mapped designations are shown on the planning and environmental plans in Appendix 5. The site is a designated area of open space and half of the site (eastern section) is designated as a nature conservation area. The site is also within the Aerodrome Safeguarding – Heathrow 90m and 150m. The site itself is not within a designated conservation area, however, the area to the west and north of the site area are designated conservation areas. Parts of the site are also within Flood Zone 2. Hammersmith Road is designated as a Borough Distributor Road.

2.1.7 Hammersmith Underground Station (District and Piccadilly Line) is located

approximately 500m (walking route) to the east of the site and the Hammersmith Underground Station (Hammersmith and City Line) approximately 550m to the east of the site.



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3 PROPOSED USE OF SITE – CONSTRUCTION PHASE 3.1 Construction requirements

Site use

3.1.1 The proposed site would occupy an area of approximately 4,730m2. The site is being considered as a drive site for:

• A 3.5mID TBM drive to the south • A 3.5mID TBM drive to the north of the catchment area

3.1.2 The site is not suitable for use as an interception point for any of the required interceptions. Scope of permanent works planned at this site

3.1.3 The proposed construction phase layout options for this site are located in Appendix 3 and are based on a preliminary assessment. If the site proceeds to the next stage as a preferred site, construction phase layouts would be optimised for efficiency and to minimise impacts.

3.1.4 The following works are proposed:

• Construction of a shaft • Driving of a minimum 3.5mID tunnel to the south using a TBM via Mund

Street, a distance of 3.2km • Driving of a minimum 3.5mID tunnel to the north of the catchment area

using a TBM, a distance of 2.1km • Installation of odour control system • Provision of ancillary equipment Temporary structures within the site

3.1.5 During the construction period, the site is likely to include the following large structures:

• Acoustic building over shaft, approximately 60m long, 30m wide, 9m high • 2 No gantry cranes (operating within the building during nightshifts) • Spoil bin, approximately 6m high • Conveyor running from building to an approximately 8m high discharge

over the spoil bin • 3 or 4 cement silos, approximately 12m high • Triple stacked offices and welfare

3.2 Construction programme

Construction programme 3.2.1 The site would be required for construction for a period of approximately 3 to 3.5

years.



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Construction phases

3.2.2 The site work is likely to be undertaken in a number of phases:

• Utility diversions if required (not included within on the above programme) • Site mobilisation • Shaft sinking • TBM tunnelling to the south • TBM tunnelling to the north • Shaft fit out • Site demobilisation and site landscaping

3.3 Construction working hours

3.3.1 The following working hours are anticipated for use of this site:

Days Hours of work

Site establishment, shaft sinking, finishings and demobilisation

Mon to Fri 07:00 to 19:00

Sat 07:00 to 13:00

Sun No work

Tunnelling Mon to Sun 24 hours Note: A single Working Day = 12 hours between 7am and 7pm. Working hours and days are dependent on the construction programme and local restrictions requiring further consideration with the Local Authority.

3.4 Access and material movements Transport of excavated material

3.4.1 The site is not adjacent to a railway and the use of rail depot would require road transport between depot and site and a considerable quantity of re-handling. There is likely to be considerable difficulties with available space for re-handling and storage, and with the availability of train paths. The site is therefore not considered to be suitable for rail transport.

3.4.2 The site is a considerable distance from the river, and hence is not considered suitable for barge transport.

3.4.3 It has therefore been assumed all material excavated from the shaft and tunnels

would be taken from site by road.

Transport of materials, plant and equipment 3.4.4 The site is not considered suitable for rail or barge transport, and hence all

material, plant and equipment to and from site would be transported by road.

Access and egress 3.4.5 The following access and egress options have been identified: 3.4.6 The access to site would be:



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• A315 Hammersmith Road travelling from the East • Turn left into site

3.4.7 The exit from site would be:

• Turn left from site onto A315 Hammersmith Road • Head West along A315 Hammersmith Road

Site management and workforce:

3.4.8 The site is not sufficiently large to contain a large site car park, and hence it is

important that most people arrive by public transport. A minibus pickup service from a local station would be required. It is unlikely that the main project offices can be accommodated on site, but there appears to be suitable commercial property lets in the area.

3.5 Construction methodology

Shaft

3.5.1 The drive shaft is likely to be constructed using a combination of jacked caisson, underpinning and Sprayed Concrete Lining (SCL) shaft sinking methods.

3.5.2 For a jacked caisson, hydraulic rams are used to push pre-cast concrete segmental shaft rings into the ground with an excavator with a hydraulic grab attachment on surface used to remove the spoil. If groundwater conditions require this, the shaft is excavated underwater (‘flooded’). As the excavation proceeds, additional shaft segments are placed on top of the previous ring.

3.5.3 In the underpinning method, the shaft is excavated dry with excavation plant within the shaft serviced by a crane on surface. Additional pre-cast concrete shaft lining segments are built at the shaft base, hanging from the previous ones.

3.5.4 It is likely that the lower sections of the shaft would be constructed using the SCL

technique. Spoil would be removed by an excavator, and rapid setting concrete sprayed onto the exposed ground to form a structural lining.

3.5.5 The choice of method depends on the ground and groundwater conditions, which

would be the subject of site investigation boreholes. As part of the process of completing the shaft the following surface level infrastructure would be installed:

• 1 No. 1.5m2 Manhole cover for man rider access to the shaft; • 1 No. 750mm x 750mm Manhole cover for staff egress during an

operational emergency; • 1 No. 4m x 2m Manhole cover for material and equipment access. • A Number of small 200mm x 200mm x manhole covers to protect davit and

safety railing sockets.

Tunnels

3.5.6 Short start-up tunnels would be created from the base of the shaft. These would be likely to be constructed using Sprayed Concrete Lining (SCL) techniques, where the spoil is removed by an excavator, and rapid setting concrete sprayed onto the exposed ground to form a structural lining.



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3.5.7 The strategic sewer tunnel would be driven by a tunnel boring machine (TBM),

which would excavate the ground using a slowly rotating cutterhead fitted with tungsten carbide tipped steel teeth. The excavated spoil would be transferred by conveyor to skips forming a train on a temporary construction railway running in the tunnel invert. The skips would be tipped at the drive shaft and the spoil lifted from the shaft by conveyor or using a skip hoisted by the shaft crane.

3.5.8 As the tunnel is excavated, the TBM erects a tunnel lining consisting of a ring of

precast concrete segments. These are erected mechanically within a steel can at the rear of the TBM, to ensure the ground remains fully supported. The concrete segments are cast to a very high standard in a specialist manufacturing facility off site and delivered to site. As excavation progresses, the void between the rear of the concrete ring and the ground is filled with a cementitious grout, which is batched in a site batching plant. The cement and PFA (pulverized fly ash) for this are delivered to site in bulk tankers and stored on site in silos.

3.5.9 The TBM would be erected in sections, weighing up to 120t each. These would be

delivered to site as special loads with the required escorts. A 400 or 500t mobile crane would be used to lower the sections down the shaft, where they would be connected, and the various systems tested and commissioned. A large number of back up gantries are towed behind the TBM, housing plant and equipment and welfare units. These would be delivered to site in sections and assembled before lowering into the shaft.

3.5.10 When the TBM reaches the reception shaft, it is dismantled again, and the

constituent parts lifted and transported off site.

Odour control

3.5.11 It is currently anticipated that ventilation and odour control would be required at this site. A system of active mechanical plant and passive installations would be used to manage the air transfer into and out of the sewer network. The active sites would extract air to create air flow along the length of the sewer. The passive sites would draw air in as a negative pressure is created by the active sites, thus completing a process of air change. The system would aim to accommodate 1 air change per day.

3.5.12 The scale of installation at each of the sites would depend on its function and whether it is an active site or a passive site. At this point there has been no dispersion or computational fluid dynamic (CFD) modelling at any of the sites. At this time there is a possibility that St Paul’s Gardens could be either an active or a passive site. This is anticipated to include construction of below ground odour control chambers each of which would have the following: • 3 No. 750mm x 750mm access manholes • 1 No. 1.5m x 800mm materials access manhole • Up to 12 No. 450mm x 450mm inspection covers

3.5.13 The odour control processes anticipated to be installed during construction would also comprise the following:

• 1 No. 1.2m diameter pressure release vent stack minimum 4m high



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• 1 No. 1m diameter pressure medium and low pressure inlet vent structure estimated at minimum of 2m high.

• 2 No. above ground fans with acoustic enclosures assume 2m x 3m x 2m high. (Active site only)

• 1 No. 3 to 5m diameter ventilation stack minimum of 15m high incorporating 2 No. treated ventilation columns and 1 bypass vent column. (Active site only)

• 1 No. 1.5m diameter ventilation column for treated are release and inflow (passive site only)

3.5.14 For both passive and active types of system the following equipment would be

installed during construction:

• Carbon panel filters odour control units (within a below ground concrete structure or above ground building)

• Controlled air inlet structure (assumed as 2m x2m x 2m above ground structure)

• High pressure release structure (assumed as 3m x 2m x 2m above ground structure)

• Below ground access ducting • Common drainage points from panel filter structure and vent structure to

local drains • Hydrogen Sulphide (H2S) sampling points before and after the filter panels

3.5.15 For the passive system the following would also apply:

• Minimum 4m high ventilation column structure

3.5.16 For the active system the following would apply: • 15m high compound ventilation column with two number treated ventilation

columns and pass ventilation column. (Diameter assumed to be 3m to 5m minimum)

• Minimum 4m high pressure release ventilation column (diameter assumed to be 1.5mm diameter minimum)

3.5.17 The sizes of the passive filters have been standardised as far as possible with a

range from approximately 4.9m x 1.9m to 7.7m x 4m (internal plan dimensions) with depth chambers varying from 2.5m to 4.5m deep. It should be noted that these sizes are indicative at this stage and dependent on future dispersion and air flow (CFD) modelling, as well as background monitoring of the individual sites to establish current ventilation arrangements that may contribute to satisfying the requirements indicated above.

3.5.18 Of equal significance is the layout of buildings and location of these sites as well as the type of use of the buildings. Other criteria such as exit velocities from the ventilation structures would need to be considered and would dictate the actual sizes adopted in the final design. Ancillary equipment

3.5.19 To facilitate the operation of mechanical equipment installed at the site a GRP

kiosk measuring 2m x 1.5m x 2m high would also be installed above ground to house telemetry, and control panels for penstock operation.



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4 PROPOSED USE OF SITE – OPERATIONAL PHASE 4.1 Permanent installations 4.1.1 The shaft remains as a permanent structure, probably containing a penstock, and

access would be required for maintenance. As the shaft is a vortex dropshaft, a small control building and odour control stack is likely to be required. The operational layout for the site is provided in Appendix 4.

4.2 Maintenance access

4.2.1 Maintenance access would be required at all shaft locations, below ground structures, kiosks and weir structures. A full inspection of the main sewer alignment is expected to be required at least once every 10 years.

4.2.2 This activity would require the use of a mobile crane and support vehicles to enable safe operation. Regular maintenance of penstocks would be required on a more frequent basis and it should be anticipated that access would be required to operate and maintain penstocks on a 2 yearly basis.

4.2.3 Access to the control kiosk would be required at all times. Hydrogen sulphide

sampling equipment would be housed in the kiosk and it anticipated that access would be required at various point throughout the year. The actual frequency would be dictated by the operation of the sewer, concentration of the odorous gases, odour control media, and ventilation equipment.

4.2.4 Access to the odour control chamber would be required at all times. Odorous

gasses would be monitored and filter media would be changed as and when required. This would be dictated by the sampled gases leaving the chamber, which would be monitored at regular intervals.

4.2.5 CFD and dispersion modelling, together with process design would be used to

ascertain the effective design life of the carbon filter media before it requires replenishing/replacement to establish a maintenance regime. It is anticipated that a number of these maintenance visits would be scheduled to coincide with each other.

4.2.6 Maintenance access would require vehicular access to the site. The operational

activity being carried out would dictate the number of vehicles and personnel required at any one time. It would also dictate when the operation can be carried out. With all sewer operations there is a high probability that night time access may be required at some point.

4.3 Restoration and after-use

4.3.1 The site would require above ground structures as set out in section 4.1. Access and maintenance requirements would necessitate the need for hard standing areas around the shaft and buried chambers. Depending on the loading requirements of the site, the design of the hard-standing would be as close to original as possible.

4.3.2 Where enhancement of the area is possible this would be considered. It is anticipated that the GRP kiosk would be green in colour according to Thames Water’s standard details and where possible would normally be set towards the



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boundary fence, location allowing. If the location of the kiosk is prominent or intrusive to a sensitive area, it is possible to house this within a small building or other structure.

4.3.3 All other existing surface features would be returned to their original state and location where possible. Where the physical location of items is not possible they would be relocated as close as possible to the original location.



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5 ENGINEERING ASSESSMENT 5.1 Construction Traffic

Transport of excavated material, materials, plant and equipment

5.1.1 The site is not suitable for rail transport or for river transport. It is therefore

assumed that all materials to and from site would be transported by road. 5.2 Construction works considerations

Traffic Management

5.2.1 Some traffic control may be required for the site entrance and exit. 5.3 Permanent works considerations

5.3.1 Operational and maintenance access would be required at this site. Above ground

structures are detailed in section 4.1 and are envisaged to be required at this time. Permanent works would be minimised during the design development where possible to reduce the impact on the site location, and wider area.

5.4 Health and safety

5.4.1 In addition to those risks that are normally associated with this type of works, the following health and safety risks must be managed: Vehicle movements

5.4.2 Wherever possible, sites should be designed with one way traffic using separate entrances and exits, with a one-way system on site, no vehicle reversing, and segregated vehicle and pedestrian routes. This would be difficult to achieve as the proposed entrance and exit are close together on the northern boundary of the site.

5.5 Summary 5.5.1 The site cannot be used as an interception site, and would require an additional

site for interception if used as a drive site.

5.5.2 The site is relatively small, and safe access to and from the site are likely to sterilise a significant portion of the site area, reducing the available space. The site is likely to be constrained by the adjacent hotel, a ‘kiln’ in the west of the site, and a building to the south, along with both entrance and exit being on the north of the site. The site is a non-regular shape, which reduces the ‘useful’ space. These factors reduce the effective site area to less than the desired minimum, and make the creation of an efficient tunnelling site layout difficult.

5.5.3 It is likely that relatively few service diversions would be required to facilitate the works. The site does not appear to have a readily available electrical power supply for the driving of the TBMs, and would require the installation of a new supply.

5.5.4 In summary it is considered that St Paul’s Gardens is less suitable in engineering

terms for a drive site.



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6 PLANNING ASSESSMENT 6.1 Introduction 6.1.1 The planning assessment covers the following areas:

• Planning applications and permissions • Planning Policy

6.2 Planning applications and permissions 6.2.1 In April 2013, permission (2012/01183/FUL) was granted for the change of use

from offices and residential to a 35 bedroom hotel located within the St Paul’s School building at 153 Hammersmith Road. The hotel opened in July 2014.

Summary 6.2.2 Although there are no planning permissions that have the potential to be directly

affected by the proposed development for this site, the hotel located adjacent to the site and operating since July 2014 has the potential to be affected by the proposed development. This site is therefore considered less suitable. The potential amenity impacts on the hotel during the construction phase are discussed further in Section 7 and Section 8.

6.3 Planning policy 6.3.1 The strategic spatial planning strategy for the area is provided in the London Plan

Spatial Development Strategy for Greater London (July 2011) and the Revised Early Minor Alterations to the London Plan (October 2013). The Examination in Public (EiP) on the Draft Further Alterations to the London Plan (January 2014) closed at the end of September 2014.

6.3.2 The local planning policy context is provided in the London Borough of Hammersmith and Fulham’s Local Plan documents, which consists of the Core Strategy, adopted in October 2011 and the Development Management Local Plan, adopted in July 2013 and adopted Supplementary Planning Guidance (SPG) and Documents (SPD).

6.3.3 The following analysis does not include the assessment of national planning policy

or guidance, nor borough wide SPGs and SPDs. This assessment does however include analysis of SPDs or SPGs that are site specific and relevant to the site being addressed.

6.3.4 There are a number of relevant planning policies and designations, which define

the proposed development on the site. These policies are tabulated in Appendix 6, and their requirements are summarised below. Key planning and environmental constraints relevant to policies listed below are shown on the planning and environmental constraint drawings provided at Appendix 5 to this report. Sustainable Construction

6.3.5 The Development Plan requires development activities to work to the principles of

sustainable construction. In view of the sites proximity to sensitive land uses, especially the Listed Grade II Hotel, it is key that these issues are addressed as



14

part of the works for the site. London Plan policies 5.3, 5.18, and 5.21, and Borough Plan policies CC3 and DM H5 are key in this regard.

Transportation

6.3.6 The site requires access from a Borough Distributor Road. Consideration of London Plan policy 6.14, and Borough Plan policies T1, DM J1 and DM J6 is key.

Water Quality and Flooding

6.3.7 The development plan generally approaches the issue of water quality and flood

risk to ensure control over development that impacts upon the water environment. However, support is also provided in the development plan for the Counters Creek development proposals which also needs to be taken into account. Therefore, London Plan policies 5.12, 5.13 and 5.14, and Borough Plan CC2, along with paragraph 10.21, would be key to any development. Heritage

6.3.8 The location of a grade II listed structure (Masters Lodge and Porters Lodge,

Boundary Walls and Circular Garden Building to St. Paul’s School) within the site and the site’s location immediately adjacent to a conservation area would require sensitive consideration as part of any proposals. As such London Plan policies 7.4 and 7.8, and Borough Plan policies BE1, DM G1, and DM G7 should be addressed.

Trees

6.3.9 Where development would affect or lead to the loss of trees it is necessary to

consider the policy requirements in respect of protection, loss and compensation, particularly where any trees are identified as being under the provisions of a Tree Preservation Order. In this regard London Plan policies 7.19 and 7.21, and Borough Plan policy DM E4 would apply. Amenity

6.3.10 The site would directly affect an area of public open space. It would also affect a number of nearby residential properties. The range of effects would include those arising from loss of access, noise, dust, air quality, vibration, visual and recreational impacts as well as, potentially, the design of any permanent infrastructure. It would therefore be important that London Plan policies 3.16, 6.10, 7.5, 7.14 and 7.15, and Borough Plan policies CF1, DM H8 and DM H9 are addressed by any proposed development.

Summary

6.3.11 Aside from strategic support in the development plan for the Counters Creek scheme as a whole there are no specific policies, or site allocations or safeguarded route alignments that benefit from promotion by development plan policy.

6.3.12 Consequently, the strategic sewer development is not itself supported by specific provisions that identify this site and so use of this site for the purposes outlined in Sections 3 and 4 of this report would run counter to existing development plan



15

provisions and require justification of its use by other relevant material considerations. For this reason, use of this site is considered less suitable.

6.3.13 The sites’ designation as an area of open space, its’ location adjacent to a conservation area, a listed building and curtilage structures (Masters Lodge and Porters Lodge, Boundary Walls and Circular Garden Building to St. Paul’s School) as well as the historic link associated with the park also identify the site as being less suitable for development.



16

7 ENVIRONMENTAL ASSESSMENT 7.1 Introduction 7.1.1 The following sections summarise specialist assessments which are provided in

Appendix 7 – Environmental Appraisal Tables. 7.2 Transport 7.2.1 Access to the site could potentially be provided from the existing access on the

A315, Hammersmith Road. However, improvements such as widening would be required along with the provision of a banksman or signals. Liaison with the highway authority and Transport for London (TfL) should take place to determine the feasibility of the options. Currently, a peak of 140 HGV movements is anticipated per day. The implications of this are subject to further investigation as part of the ongoing transport assessment.

7.2.2 No river or rail access is available within the vicinity of the site. There is no parking

available on Hammersmith Road and limited parking is available within the vicinity of the site. The site features a high Public Transport Accessibility Level (PTAL) score indicating that staff would be able to access the site by public transport.

7.2.3 On the basis of the information available it is considered that the site is suitable,

as the road layout in the surrounding area is suitable for HGVs. The site would be subject to modifying the existing access and agreeing a traffic management strategy with the highway authority and TfL.

7.3 Noise 7.3.1 In terms of noise, this site is suitable due to the high ambient noise levels at the

receptors in the vicinity of the site, and the potential to locate noisy equipment away from residential receptors. Substantial adverse effects are not predicted to be likely at the nearest noise sensitive receptors.

7.4 Water resources - hydrogeology 7.4.1 In terms of hydrogeology, this site is suitable because the shaft excavations would

be constructed through the Superficial Deposits (upper aquifer), if present, which is classified as a secondary A aquifer, and would be founded in the London Clay Formation (aquiclude) and are not anticipated to extend into the Chalk Formation (lower aquifer), which is classified as a principal aquifer.

7.4.2 The tunnel excavations would be through the London Clay Formation. Sheet piling is anticipated to be required to seal out the upper aquifer and seepages in the aquiclude. Therefore, no impacts on groundwater levels or flows are anticipated on the upper aquifer.

7.4.3 There is a licensed groundwater abstraction 1km from the shaft location which abstracts from the Chalk formation. The excavations are not anticipated to extend into the Chalk Formation (lower aquifer) and therefore no dewatering should be required. Therefore, no impacts on groundwater levels, flows or abstractions are anticipated on the lower aquifer. There are no unlicensed groundwater abstractors, Source Protection Zones or Sites of Special Scientific Interest within 1km of the shaft location.



17

7.5 Water resources – surface water and flood risk 7.5.1 In terms of surface water resources, this site is suitable because there is no direct

pathway for pollution to be transmitted to the nearest surface water receptor. 7.5.2 In terms of flood risk, the site is suitable as it is defended from flooding from the

River Thames and is at very low risk of flooding from surface water. 7.6 Air quality 7.6.1 The site is considered less suitable because the sensitivity of the area to dust

soiling effects associated with construction, earthworks and trackout is high to medium. There is also the potential for additional exhaust emissions due to traffic management required for the construction of the shaft and tunnels to cause localised air quality impacts; these impacts are undefined at present. As described above, it is likely it would require additional site specific mitigation beyond standard mitigation measures if selected to make it suitable.

7.7 Archaeology 7.7.1 There is evidence for post medieval archaeology in the vicinity of the site but this is

likely to be of low significance. There is also the possibility of below ground remains associated with medieval occupation in the area to be present within the site. On the basis of the information provided it is considered that the site is suitable because there are unlikely to be any archaeological remains present that would represent a constraint.

7.8 Built heritage 7.8.1 The site is not located within a Conservation Area. However, the Brook Green and

Gunter Estate Conservation Areas and two further grade II listed buildings/structures are located in close proximity (Colet Court School and St. Joseph’s Alms Houses).

7.8.2 There may be a potential impact upon these grade II listed structures and the two Conservation Areas, resulting from development within their setting. However, given the local precedent of modern development and the resulting change in character of the immediate environs, the presence of these built heritage assets should not represent a constraint.

7.8.3 A Grade II listed structure (Masters Lodge and Porters Lodge, Boundary Walls and Circular Garden Building to St. Paul’s School) is located within the site itself and may be directly impacted. The site has historic value as the site of the former St Paul’s School, designed by Alfred Waterhouse.

7.8.4 The Grade II listed Masters Lodge and Porters Lodge are still located immediately

to the east, and the Circular Garden Building and the Boundary Walls and railings within the site (which are part of the listing) are still present. The potential physical impact upon them, and impacts upon their significance as a result of development within their setting would need detailed assessment, and listed building consent would be required.

7.8.5 On this basis it is considered that the option currently proposed for this site is less suitable.



18

7.9 Townscape and views

7.9.1 During construction, there would be temporary adverse townscape and visual impacts, with temporary adverse impacts on views from the adjacent hotel. Mature trees should be retained on site as far as possible, given the constrained site area.

7.9.2 In the long-term, visual amenity within the park would be adversely impacted by the presence of the permanent elements such as the odour control stacks and equipment. Therefore, it is considered that the site is less suitable. The careful design and location of the permanent elements within an appropriate landscape scheme would minimise potential long-term impacts on St Paul’s Gardens.

7.10 Ecology

7.10.1 The site is less suitable because the site is identified as St Paul’s Open Space SLI and, in addition, habitats within the site are listed as the London BAP habitat ‘Parks and Urban Greenspaces’.

7.10.2 If this habitat is lost or degraded, compensatory provision may be required to

enable works to proceed within the site. The site has potential to support protected species such as bats, stag beetles and nesting birds. If any of these species are identified to be utilising habitats to be impacted upon by proposed works within the site, avoidance and mitigation measures would be required.

7.11 Land quality 7.11.1 On the basis of the information available, it is considered that the site is suitable.

The site has not been previously developed and has been open space (St Paul’s Gardens) since the earliest map reviewed. The 1873 map shows the site as an open field immediately to the south of the established Hammersmith Road.

7.11.2 The surrounding land has not included activities or uses that are considered to

represent a substantial risk of ground contamination at the site. Therefore, the likelihood of contamination at the site is considered to be low.

7.12 Cumulative effects 7.12.1 The potential for cumulative effects of the Counters Creek scheme with other

proposed developments will be considered at the planning application stage. A cumulative environmental assessment will consider the likely impacts from other developments, which individually might be minor but when considered together, could give rise to more substantial cumulative effects. It will focus on the impacts of other nearby schemes where construction would be likely to take place during the construction phase of the Counters Creek scheme.

7.12.2 Other development considered will in most cases be limited to development which is in close proximity to the Counters Creek scheme and which has a valid planning permission but is yet to commence. For example, the Thames Tideway Tunnel and the Lots Road Power Station redevelopment will be considered as part of the future baseline at Cremorne Wharf.

7.12.3 Any committed developments within the local area, such as the redevelopment of

Earls Court and Kensington Olympia, or the promotion of Crossrail 2 (safeguarded



19

route), are also likely to be considered for inclusion within the cumulative environmental assessment.

7.12.4 In particular, it is recognised that without mitigation there could be a cumulative

traffic impact on the surrounding road network and this is something which is being investigated as part of the ongoing transport and environmental assessments of the Counters Creek scheme.



20

8 SOCIO-ECONOMIC AND COMMUNITY ASSESSMENT 8.1 Socio-economic profile 8.1.1 The site is within the Avonmore and Brook Green ward of the London Borough of

Hammersmith and Fulham. Statistics from the Office of National Statistics (ONS) 2011 Census data show the following indicators for the ward, in comparison with the rest of the borough, London and England as a whole. • Housing Tenure of 17.2% owner occupied (owns outright) homes, 10.2%

council rented with another 11.8% in other forms of social housing (Housing Associations / Registered Social Landlord)

• In terms of social mix, 47.8% people in the ward were born in the UK and 64.6% are white (including white British and other)

• The median age of the population in the ward is (32 years) is less than that of London (33 years) and England (39 years).

8.1.2 The data also suggests that the site is located within a community with a high

concentration of professionals. The percentage of people (3.9%) with large employers and higher managerial and administrative occupations residing in the ward is more than those in London (2.5%) and in England (2.4%).

8.2 Issues and impacts 8.2.1 Due to the proposals for a drive shaft and associated above ground structures, as

set out in Section 3 of this report, the greatest potential impact would be the loss of access to open space. There are a number of trees on the site, pedestrian footpaths and open grassed space. The open space is designated as a small local park and open space in the borough planning policy hierarchy of Local Parks and Open Spaces. The impacts of development are likely to affect the local community, as well as users from further afield.

8.2.2 There are residential buildings to the south of the site, which have an access point

through a (currently locked) walkway located within the site. The Masters Lodge and Porters Lodge building (Former St Paul’s School) is located to the east of the site and is Grade II listed. The St Paul’s Hotel currently occupies those premises. In addition, the boundary walls located along the northern and western boundaries of the site, and the small circular kiln building to the west of the site are both Grade II listed. To the east of the site is the St Mary’s Church, and to the north is Lyric House, occupied by office use. Any impact on these is likely to affect the local community, as well as users from further afield. Mitigation would be required during the construction phase and compensatory open space is likely to be required if the proposals result in the loss of open space.

8.2.3 Access to the site is from a designated Local Distributor Road and would require

careful planning and management to minimise traffic impacts. 8.3 Potential interest groups 8.3.1 There are a number of interest groups functioning in the area, these include the

following: • London Parks and Gardens Trust • The Hammersmith and Fulham Historic Buildings Group



21

• The Hammersmith Society • The Fulham Society

8.3.2 To ensure that the views of these interest groups, along with those of the wider

public and of statutory stakeholders, are fully captured and addressed through any detailed development process, a detailed communications strategy would be developed that enables the opportunity for consultation on emerging sites, and as the selected Scheme progresses towards submission as a planning application.

8.3.3 This process would need to ensure that consultation reaches both those who would directly benefit from the development, and those who may not experience any direct benefit but would experience impacts during the construction process.

8.4 Summary 8.4.1 In terms of residential amenity impact the site is considered less suitable due to

the close proximity of residential properties. The potential for negative amenity impacts on the hotel residents also makes this site less suitable.

8.4.2 The site is a designated area of open space and is therefore considered less

suitable due to the potential impact on community assets.



22

9 PROPERTY ASSESSMENT 9.1 Introduction

9.1.1 The land here is public open space and is owned by and located in the London

Borough of Hammersmith & Fulham. The building and land were formerly part of St Paul’s School.

9.2 Crown Land and Special Land comments 9.2.1 None to report at this time.

9.3 Land to be acquired

9.3.1 The works would require the open space to be acquired temporarily as a working

area. A small area would be required permanently to accommodate any above ground permanent works, such as cabins/kiosks etc.

9.4 Associated Property costs to project 9.4.1 Assuming the underground works are covered under Schedule 12 of the W.I.A. the

potential impact on the open space site is limited and could be returned to open space upon completion of the works.

9.4.2 Temporary use of the open space would likely be documented via a compound

licence. A financial consideration would be required for this element. The financial considerations associated with this option are low/fair.

9.5 Compensation 9.5.1 No compensation matters are reported at this time. 9.6 Summary 9.6.1 The site provides sufficient space for a workable design to be incorporated. The

site has limited property related restrictions affecting the site potential use. 9.6.2 In summary it is considered that St Paul’s Gardens is suitable in property terms.



23

10 SITE CONCLUSIONS

10.1 Engineering 10.1.1 In summary it is considered that St Paul’s Gardens is less suitable in engineering

terms for a drive site.

10.2 Planning 10.2.1 Due to the potential for amenity impacts upon the newly opened hotel immediately

adjacent to it the site is considered to be less suitable in planning application terms.

10.2.2 The sites’ designation as an area of open space, its’ location adjacent to a conservation area, a listed building and curtilage structures (circular garden building and boundary wall) as well as the historic link associated with the park, and the absence of policy support for its use for the strategic sewer means that this site is also considered to be less suitable for development in planning policy terms.

10.3 Environment

10.3.1 From a transport perspective, the site is suitable as there is the potential to provide access from the A315 Hammersmith Road, although it would require improvements. Use of the site is dependent on discussions with the highway authority and Transport for London, to agree a traffic management strategy and modifying existing access.

10.3.2 From a noise perspective, the site is suitable due to the high ambient noise levels at the receptors in the vicinity of the site. The site also provides the potential to locate noisy equipment away from residential receptors.

10.3.3 From an environment perspective, the site is suitable for development from the perspective of hydrogeology, surface water and flood risk, archaeology and land quality. The site is considered less suitable for development from the perspectives of air quality, built heritage, townscape and visual and ecology.

10.3.4 Overall the site is considered suitable. Further investigation would be required as

to whether air quality, built heritage, townscape and visual and ecology could be adequately mitigated. Likely mitigation considerations could include the following:

• Air Quality: Measures to ensure dust is adequately mitigated for closest

receptors; • Built Heritage: Use of hoarding and appropriate lighting during construction

and high quality design and location of the permanent elements to minimise long term impacts. Listed building consent would be required for this development;

• Townscape and Visual: Retention of mature trees and vegetation around the boundary (if possible) to filter views of construction activities. Site restoration following construction, incorporating an appropriate landscape scheme; and

• Ecology: Compensatory habitat provision may be required to enable works to proceed within the site. Avoidance and mitigation measures may be required should bats, stag beetles and nesting birds be identified to be utilising habitats on site.



24

10.4 Socio-economic and community 10.4.1 In terms of residential amenity impact the site is considered less suitable due to

the close proximity of residential properties. The potential for negative amenity impacts on the hotel residents also makes this site less suitable. The site is a designated area of open space and is therefore considered less suitable due to the potential impact on community assets.

10.5 Property 10.5.1 The site provides sufficient space for a workable design to be incorporated. The

site has limited property related restrictions affecting the site potential use. In summary it is considered that St Paul’s Gardens is suitable in property terms.

10.6 Recommendation 10.6.1 The site is only considered to be suitable for the proposed use from a property

perspective, with all other assessments identifying the site as being less suitable. No assessment identified the site as unsuitable.

10.6.2 Given this outcome it is concluded that the site is less suitable. However, as there are other identified alternative drive site exist which have been assessed as being more readily capable of accommodating the proposed use, the site is held in reserve and will not be considered further unless those alternative sites are unavailable.

APPENDIX 1 BACKGROUND INFORMATION

1.1 Background to the project

The Counters Creek Catchment

1.1.1 Counters Creek is one of the ‘lost rivers’ of London. It was culverted over in the mid 19th Century and connected into the interceptor sewerage network then being developed for London by Sir Joseph Bazelgette. The Counters Creek sewer catchment encompasses parts of Hammersmith and Fulham and Kensington and Chelsea and extends as far north as Westminster, Camden, Brent and Ealing.

1.1.2 This former river, its catchment and the sewer system form part of Thames Water’s sewerage network, drains all surface water from buildings and roads, as well as wastewater.

1.1.3 The sewerage system was constructed to take flows to Beckton Sewage Treatment Works. In early 20th Century, as London grew and the amount of land lying under impermeable surfaces increased, the volumes of flows in times of storms increased significantly.

1.1.4 Since then an extensive and complex sewer system comprising a series of storm

relief sewers (as shown on Figure 1) has been constructed to transfer excess storm flows to the River Thames when the sewers become full. This system has evolved to protect the low-lying land from an increasing risk of flooding caused by urban development.

1.1.5 As Hammersmith and Fulham and part of Kensington and Chelsea are low lying areas in relation to the tidal river levels, it was not possible for the storm relief sewers to discharge into the river by gravity (without pumping). Hammersmith, Lots Road and the Western pumping stations were subsequently constructed to serve the storm relief sewers within the two boroughs (as shown on Figure 1).

Figure 1 The development of the interceptor and storm relief sewerage systems in the Counters Creek Catchment.

Key and timeline for Figure 1

1850 Counters Creek

1930s Walham Green Hammersmith Brook Green

1860s Low Level Nos. 1& 2 Interceptors (dashed green line) – Kings Scholars Pond.

1940s Hammersmith Brook Green

1880s – Ranelagh

1950s Walham Parsons Green

1900s Mid Level 1 & 2 Interceptors (dashed purple line)

1960s Hammersmith, Counters Creek Duplicate

1920s Hammersmith Main Line – North Western

1980s North Western

1.1.6 The continuing growth of outer London resulted in the extension of the sewer

system northward and hence additional flows from the upper catchment entering the sewer system serving the low lying Counters Creek areas.

1.1.7 The additional flows have led to overloading and water levels within the existing sewers and manholes to rise. The increase in the water levels has in turn led to flows backing up the connection pipework into basements that were built at almost the same level as the sewer. The ever-increasing redevelopment of basements from storage areas into habitable properties in recent years has now brought this problem to the fore. The basement flooding problem

1.1.8 Thames Water began investigating the flooding problem following the storms of

2004 and 2007, when the majority of the basement flooding complaints were received. Information was recorded in the Counters Creek flood register, a register

N

of all the properties in the Counters Creek Catchment that have been recorded as being flooded at some point in the past.

1.1.9 This register is in turn taken from the Thames Water Sewer Flooding History Database (SFHD). Properties are added to the register based on reported flooding incidents. Incidents are assessed to confirm whether or not the flood event was caused by an operational problem (i.e. a blockage), an extreme rainfall occurrence (greater than the current design criteria), or by a lack of capacity in the sewer.

1.1.10 The Counters Creek Flooding Register currently shows that over 1,700 properties

are subject to flooding within the London Borough of Hammersmith and Fulham and the Royal Borough of Kensington and Chelsea.

1.1.11 Sophisticated hydraulic models were used to simulate and verify the extent of basement flooding in the area and the results confirmed the existence of a widespread problem. Thames Water has examined the cause of flooding and determined that whilst there was no single cause, the flooding is generally caused by two main factors:

i. When sewers become inundated by storm water runoff, local sewer water

levels rise and back up the connection pipework into basements properties. ii. For many other properties, the hydraulic analysis indicated that flooding

was not solely caused by local surface water inundating the local sewerage network. Under certain storm conditions, storm relief sewers in the area run at full capacity (generally from the flows entering the system from the upper parts of the catchments), leaving inadequate capacity to provide relief for storm flows in the lower parts of the catchment. Therefore, flows build and back up into the connection pipework and then into basement properties.

1.2 Developing a strategic solution to the problem 1.2.1 Figure 2 below shows the locations of properties that have reported basement

flooding (the coloured dots), illustrating that the locations at which flooding occurs are widespread throughout the two boroughs.

1.2.2 The different coloured dots shown in Figure 2 indicate the type of solution proposed for a specific location. The Strategic Options Report (C680-TW-00503-RP) describes how each solution works, how they have been identified, the role they can play, and which solutions have been progressed.

1.2.3 The solutions comprise a strategic storm relief sewer (the strategic sewer) and

associated sewer upgrade works (properties protected by these are represented by purple dots), local package pumping systems known as ‘flooding local improvement projects’ (FLIPs – blue and red dots), local sewer upgrade works (green dots) and Sustainable Drainage Systems (SuDS – yellow dots).

Figure 2 Proposed solutions to reported basement flooding

1.2.4 The widespread nature of the basement flooding problem coupled with the fact

that there is no single cause of flooding, means that there can be no single solution. For this reason a “bottom up” approach to addressing the problem has been adopted whereby each local flooding area (cluster) has been analysed to identify a viable solution and to establish the role that might be played in each area by flow storage, sewer upsizing, FLIPs, and SuDS.

1.2.5 Consideration was then given to the opportunities for combining and rationalising

these solutions as part of the process of establishing a strategy for managing flooding in the two boroughs and flows within the catchment.

1.2.6 Whilst this approach would provide protection for some properties through the use

flow storage, sewer upsizing, FLIPs, and SuDS, it cannot do so for all properties affected by the basement flooding problem. This is because the incoming flows into an area via sewers from the adjoining areas are so significant that those incoming flows need to be intercepted, cut off, or otherwise substantially reduced.

1.2.7 It was therefore concluded that, to robustly provide for the fullest possible coverage of the flooding problem a strategic sewer is required to intercept and store the major flows that are causing sewer overloading. This strategic sewer will, when provided alongside FLIPS, SuDS and the sewer upgrade works lower the top water levels in the sewer over the whole catchment to levels that are below the level of most of the basements thereby providing flooding protection.

1.3 Summary of the site selection process 1.3.1 A site selection process has been developed to assess and identify the most

suitable locations for the range of construction sites required to deliver the

strategic sewer, namely drive shaft site(s), reception shaft site(s), interception shaft site(s), sewer outfall connections or new sewer outfalls, a pumping station and construction compounds.

1.3.2 The process takes account of engineering, environment (including noise and

transport), planning, property, socio-economic and community issues relevant to the selection of the most suitable combination of sites.

1.3.3 It draws upon other methodologies utilised for the Deephams Sewage Works Upgrade and for the Thames Tideway Tunnel to ensure that the approach and issues covered reflect best practice. Regard has also been had to the National Planning Policy Framework and the Development Plan for the area, along with key considerations affecting engineering decision-making and property assessment, when the assessment criteria in the methodology were identified. The methodology is shown diagrammatically in Figure 3 below.

Figure 3 Site Selection Methodology

1.3.4 The methodology follows a sequential multi-stage process, with some stages

undertaken in parallel. There is an iterative relationship between site selection, route alignment and engineering design whereby as the engineering team refines the route options for the storm relief sewer associated restrictions on or requirements for sites are fed into the concurrent site selection process.

1.3.5 An essential part of the methodology is the use of an ongoing review process to revisit and check the validity of previous assessments. This is undertaken as each key stage of the assessment process is completed through document review and stage workshops and enables the assessment of sites (and concurrent assessment of options reported separately) to remain valid as information changes and new information is obtained.

1.3.6 Where, for example, route alignment parameters change or available sites become restricted over time, stages in the process may be repeated (or back-checked) in order to take account of new information or other changes in circumstance.

1.4 Approach to consultation and stakeholder engagement 1.4.1 Community engagement is a key part of the strategic sewer scheme and the public

will be fully engaged with once the assessment work in Stage 3 is completed and sufficient information is available to begin public consultation under Stage 4a.

1.5 Project Programme 1.5.1 The current provisional project programme for the strategic sewer is:

• Evidence gathering / scheme development and testing: Jan – Oct 2014 • Phase 1 consultation on options: Nov 2014 – Jan 2015 • Environmental and planning assessments: July 2014 – May 2015 • Confirmation of the preferred option: May / June 2015 • Phase 2 pre-application consultation: May / June – July / Aug 2015 • Final design, planning and environmental work: July – Oct 2015 • Submission of application(s) for Planning Permission: Nov 2015 • Target for planning permission: July 2016 • Planning Conditions / Obligations discharged / procurement complete: Dec

2016 • Anticipated start on site: Jan 2017

APPENDIX 2 SITE LOCATION PLAN

APPENDIX 3 INDICATIVE CONSTRUCTION LAYOUT PLANS

APPENDIX 4 INDICATIVE OPERATIONAL LAYOUT PLANS

APPENDIX 5 PLANNING AND ENVIRONMENT PLANS

St. Paul'sGardens

HammersmithCemetery

153

Brook Green

9

245

62

D Fn

21

26

68

61

7

GIRDLERS ROAD

49

PH177 to 179

5.5m

16

Ramp

5.0m

Chy

ROWA

N RO

AD63

MERC

ERS

172

6

36

1 to 7

5

51

28

1 to 22

Playground

Police Station

55

53

1 to 6

5 to 27

194

OXFORD GATE

152

18

162

22

HAMMERSMITH ROAD

10

B

23

5.7m

4844

15 to 20

LB

RC Church

D

Hall

C

High School

SL

52

Metro

1812

4

Hammersmith Station

1437

A

Trust Buildings169 to 210

Car Park

3

TCB5.3m

12

SLs

3,4

Playing Field

1117

El Sub Sta

7,8

29

TALGARTH ROAD

West London Magistrates' Court

90

16 to 27Hotel

201 Posts

24

70 57

83

191

MARGRAVINE GARDENS102

3.7m

F

69

135 to 150

Preparatory

182

5.8m

45

71

169

6067

89

Sand Drag

8

4.7m

54

20

15

BUTTERWICK

13

19

4.9m

32

TA

34

31

159

43

Parish

112

Waterhouse Close5.1m

1

El169 to 175

Bechtel House

Infan

ts Sc

hool

42

77

YELDHAM ROAD

Buildings

55a

4.0m

Nazareth House

FB

1 to 361

27 to

61

Ophelia House

7958

Nurses' Home

4.6m

106

174

1b

School

65

136

Chester Court

ROAD

30

1 to 12

5.2m

146

School Annexe

LILY CLOSE

(Private)

25Horatio House

GREAT CHURCH LANE

33

DepotS Br

to

Sta

2 to 14

HAMMERSMITH FLYOVER

Surge

ry

130

Presby

tery

BUTE

GAR

DENS

Kings House

35

COLET GARDENS

50

CourtWilfred

161

CWFW

208 200

House

255

BPs

91

Larmenier and Sacred Heart

Jacque

s Prev

ert

Station

4.4m

5 to 12

76

3981

97

87

CR 1 to 24

40

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This document was prepared by Mott MacDonald Limited under assignment from Thames Water and the content should not be relied on or used for purposes other than those assigned,without verification from Thames Water. Mott MacDonald Limited does not accept responsibility or liability for use of this document other than that for which it was originally intended.

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APPENDIX 6 RELEVANT PLANNING POLICY

Policy / paragraph Reference

Policy title / paragraph subject

Summary of relevant policy

London Plan Spatial Development Strategy for Greater London (July 2011) and the London Plan Revised Early Minor Alterations (October 2013) Draft Further Alterations to the London Plan (Jan 2014, include July 2014 modifications)1

Policy 2.18* Green Infrastructure: the network of open and green spaces

The Mayor will work with all relevant strategic partners to protect, promote, expand and manage the extent and quality of, and access to, London’s network of green infrastructure. Development proposals should incorporate appropriate elements of green infrastructure that are integrated into the wider network and encourage the linkage of green infrastructure, including the Blue Ribbon Network, to the wider public realm to improve accessibility for all and develop new links, including green chains, street trees, and other components of urban greening.

Policy 3.16 Protection and enhancement of social infrastructure

Development proposals should support the provision of additional social infrastructure in light of local and strategic needs assessments.

Policy 4.12 Improving opportunities for all

The policy seeks to improve employment opportunities for Londoners, to remove barriers to employment and progression and to tackle low participation in the labour market. Strategic development proposals should support local employment, skills development and training opportunities.

Policy 5.2 Minimising carbon dioxide emissions

The policy requires development proposals to make the fullest contribution to minimising carbon dioxide emissions in accordance with the energy hierarchy. All major development proposals should meet the targets set out in the policy for carbon dioxide emissions reduction in buildings. In addition, major proposals should include detailed energy assessment to demonstrate how the minimum targets for carbon dioxide emissions reduction are met.

Policy 5.3 Sustainable design and construction

The highest standards of sustainable design and construction should be achieved in London to improve the environmental performance of new development and to adapt to the effects of climate change over their lifetime. Development proposals should demonstrate that sustainable design standards are integral to the proposal, including its construction and operation, and ensure that they are considered at the beginning of the design process.

Policy 5.6 Decentralised energy in development proposals

Development proposals should evaluate the feasibility of Combined Heat and Power (CHP) systems, and where a new CHP is appropriate examine opportunities to extend the system beyond the site boundary to adjacent sites.

Policy 5.7 Renewable energy The Mayor seeks to increase the proportion of energy generated from renewable sources, and expects that the projections for installed renewable energy capacity outlined in the Climate Change Mitigation and Energy Strategy and in supplementary planning guidance will be achieved in London. Major development proposals should provide a reduction in expected carbon dioxide emissions through the use of onsite renewable energy generation, where feasible.

Policy 5.9 Overheating and cooling

Major development proposals should demonstrate how the design, materials, construction and operation of the development would minimize overheating and also meet its cooling needs.

Policy 5.10 Urban Greening The Mayor will promote and support urban greening, such as new planting to the public realm (including streets, squares and plazas) and green infrastructure, to contribute to the adaption to, and mitigation of, the effects of climate change.

1 The Examination in Public (EiP) on the Draft Further Alterations to the London Plan (January 2014) closed at the end of September 2014. Policies in Appendix 6 marked with an asterisk (*) are proposed to be modified as part of this process. Once the Draft Further Alterations to the London Plan have been adopted, the relevant policies in the table will be updated.




Policy 5.12 Flood Risk Management

Development proposals must comply with the flood risk assessment and management requirements set out in the NPPF and the associated Technical Guidance on flood risk over the lifetime of the development and have regard to measures proposed in Thames Estuary 2100 and Catchment Flood Management Plans.

Policy 5.13 Sustainable Drainage

Development should utilise sustainable urban drainage systems (SUDS) unless there are practical reasons for not doing so and should aim to achieve Greenfield run-off rates and ensure that surface water runoff is managed as close to its source as possible.

Policy 5.14 Water quality and sewerage infrastructure

Development proposals must ensure that adequate sewerage infrastructure capacity is available. Proposals that would benefit water quality, the delivery of policies in the London Plan and of the Thames River Basin Management Plan should be supported while those with adverse impacts should be refused. Development proposals to upgrade London’s sewerage (including sludge) treatment capacity should be supported provided they utilise the best available technology and energy capture.

Policy 5.18 Construction, excavation and demolition waste

Major development sites are required to recycle CE&D waste on-site, wherever practicable, supported through planning conditions. Waste should be removed from construction sites, and materials brought to the site, by water or rail transport wherever that is practicable.

Policy 5.21 Contaminated Land Appropriate measures should be taken to ensure that development on previously contaminated land does not activate or spread contamination.

Policy 6.1 Transport – Strategic approach

The Mayor will work with all relevant partners to encourage the closer integration of transport and development through a range of means including facilitating the efficient distribution of freight whilst minimising its impact on the transport network and seeking to increase the use of the Blue Ribbon Network, especially the Thames, for passenger and freight use.

Policy 6.3 Assessing effects of development on transport capacity

Development proposals should ensure that impacts on transport capacity and the transport network, at both a corridor and local level are fully assessed. Where existing transport capacity is insufficient to allow for the travel generated by proposed developments, and no firm plans exist for an increase in capacity to cater for this, boroughs should ensure that development proposals are phased until it is known these requirements can be met, otherwise they may be refused. The cumulative impacts of development on transport requirements must be taken into account. Transport assessments will be required in accordance with TfL’s Transport Assessment Best Practice Guidance for major planning applications. Workplace and/or Residential Travel Plans should be provided for planning applications exceeding the thresholds in, and produced in accordance with, the relevant TfL guidance. Construction logistics plans and delivery & servicing plans should be secured in line with the London Freight Plans and should be coordinated with Travel Plans.

Policy 6.10* Walking Ensure pedestrian environments in and around new developments emphasise the quality of pedestrian and street space.

Policy 6.14* Freight Development proposals that locate developments that generate high numbers of freight movements close to the major transport routes that promote the uptake of the Freight Operations Recognition Scheme, construction logistics plans and delivery & servicing plans, and increase the use of the Blue Ribbon Network for freight transport, will be encouraged.

Policy 7.1* Building London’s Neighbourhoods and communities

Development should be designed so that the layout, tenure, and mix of uses interface with surrounding land and improve people’s access to social and community infrastructure (including green spaces), the Blue Ribbon Network, local shops, employment opportunities, commercial services and public




transport.

Policy 7.2 An inclusive environment

The Mayor will require all new development in London to achieve the highest standards of accessible and inclusive design. Development proposals should meet the highest standards of accessible and inclusive design and should demonstrate that they meet the principles of inclusive design.

Policy 7.4 Local Character Development should have regard to the form, function and structure of an area, place or street and the scale, mass and orientation of surrounding buildings. It should improve an area’s visual or physical connection with natural features.

Policy 7.5* Public Realm Development should make the public realm comprehensible at a human scale, using gateways, focal points and landmarks to help people find their way. Landscape treatment, furniture and infrastructure should be of the highest quality, have a clear purpose, maintain uncluttered spaces and should contribute to the easy movement of people through the space. Opportunities for the integration of high quality public art should be considered, and opportunities for greening such as through planting of trees and other soft landscaping wherever possible, should be maximized. Treatment of the public realm should be informed by the history of the place. Development should incorporate local social infrastructure such as public toilets, drinking water fountains and seating, where appropriate. It should also reinforce the connection between public spaces and existing local features such as heritage landmarks, the Blue Ribbon Network and parks.

Policy 7.6 Architecture Buildings and structures should: • be of the highest architectural quality • be of a proportion, composition, scale and orientation that enhances,

activates and appropriately encloses the public realm • compromise details and materials that complement, not necessarily

replicate, the local architectural character • not cause unacceptable harm to the amenity of surrounding land and

buildings, particularly residential buildings, in relation to privacy, overshadowing, wind and microclimate.

• incorporate best practice in resource management and climate change mitigation and adaptation

• provide high quality indoor and outdoor spaces and integrate well with the surrounding streets and open spaces

• be adaptable to different activities and land uses, particularly at ground level

• meet the principles of inclusive design

Policy 7.8 Heritage assets and archaeology

Development should incorporate measures that identify, record, interpret, protect and, where appropriate, present, the site’s archaeology. Development should preserve, refurbish and incorporate heritage assets, where appropriate. New development in the setting of heritage assets, and conservation areas should be sympathetic to their form, scale, materials and architectural detail.

Policy 7.14 Improving Air Quality

Development proposals should promote sustainable design and construction to reduce emissions from the demolition and construction of buildings. Development proposals need to be at least ‘air quality neutral’ and not lead to further deterioration of existing poor air quality.

Policy 7.15* Reducing noise and enhancing soundscapes

Development proposals should seek to reduce noise by minimising the existing and potential adverse impacts of noise on, from, within, or in the vicinity of, development proposals. In addition development proposals should promote new technologies and improved practices to reduce noise at source.

Policy 7.18* Protecting Local Open Space and

The policy seeks to resist the loss of locally protected open space and support the creation of new open space. The loss of local protected open spaces must




Addressing Local Deficiency

be resisted unless equivalent or better quality provision is made within the local catchment area.

Policy 7.19* Biodiversity and access to nature

Development proposals wherever possible should make a positive contribution to the protection, promotion and management of biodiversity. On sites of Importance for Nature Conservation, the policy gives the highest protection to sites with existing or proposed international designations (SACs, SPAs, Ramsar sites) and national designations (SSSIs, NNRs). The London Plan gives strong protection to Sites of Metropolitan Importance for Nature Conservation (SMIs) and gives Sites of Borough and Local Importance for Nature Conservation the level of protection commensurate with their importance.

Policy 7.21* Trees and Woodlands

Existing trees of value should be retained and any loss as the result of development should be replaced following the principle of ‘right place, right tree’. Wherever possible the planting of additional trees should be included in new developments, particularly large canopied species.

Hammersmith and Fulham Local Development Framework Core Strategy Development Plan Document (October 2011)

Borough Wide Strategic Policy LE1

Local Economy and Employment

This policy seeks to retain premises capable of providing continued accommodation for local services or significant employment unless: • continued use would adversely impact on residential areas; or • an alternative use would give a demonstrably greater benefit that could

not be provide on another site; or • it can be satisfactorily demonstrated that the property is no longer

required for employment purposes; or • an alternative use would enable support for essential public services and

is otherwise acceptable.

Borough Wide Strategic Policy CF1

Supporting Community Facilities and Services

The Council will work with its strategic partners to provide borough wide high quality facilities and services for the community by generally protecting all existing community facilities and services throughout the borough.

Borough Wide Strategic Policy OS1

Improving and Protecting Parks and Open Spaces

The policy aims to protect and enhance parks, open spaces and biodiversity in the Borough. The current use of the site is a local park, comprising hardstanding, grassed areas and a formal play area.

Borough Wide Strategic Policy BE1

Built Environment This policy requires that all development within the borough should create a high quality environment that respects and enhances its townscape context and heritage assists. In addition, the policy requires an approach to accessible and inclusive urban design that considers how good design, quality public realm, landscaping and land use can be integrated to help regenerate places. The policy also requires all development to be designed to enhance community safety and minimise the opportunities for crime, and be attractive, durable, adaptable, and accessible in order to achieve good sustainable and inclusive design. The site is adjacent to a conservation area. Policy BE1 states that development throughout the borough should protect and enhance the character, appearance and setting of the borough’s conservation areas and its historic environment, including listed buildings, historic parks and gardens, buildings and artefacts of local importance and interest, archaeological priority areas and Fulham Palace Moated Site scheduled ancient monument.

Borough Wide Strategic Policy CC1

Reduce Carbon Emissions and Resource Use and Adapt to Climate Change Impacts

Requires development to make the fullest possible contribution to the mitigation and adaptation to climate change.





Water Flooding All developments to minimise current and future flood risk and the adverse effects of flooding on people. The council will strive to reduce the risk of flooding from surface water and foul water and its contribution to fluvial flooding by requiring development proposals to include appropriate sustainable drainage systems and systems to reduce the amount of water discharged to the foul water drainage.


Waste Management

This policy promotes sustainable waste behavior, including sustainable demolition, in new and existing developments. Seeking, where possible the movement of waste and recyclable materials by sustainable means of transport, including the Grand Union Canal.


Protecting and Enhancing Environmental Quality

The council will support measures to protect and enhance the environmental quality of the borough including harmful emissions of land, air and water and the remediation of contaminated land. It will work with partner organisations to help deliver this.

Paragraph 10.21

N/A The Core Strategy at Paragraph 10.21 supports Thames Water’s commitment to “improving the Counters Creek Sewer – the principle sewer draining Hammersmith and Fulham and other adjoining boroughs. It is anticipated that improvements to the sewer will be made within Thames Water’s 2015 – 20 budgetary period. The council will work with Thames Water and other stakeholders to ensure that there is adequate water supply, surface water foul drainage and sewerage treatment capacity to serve all new developments”.

Borough Wide Strategic Policy T1

Transport This policy seeks increased use of the Thames for freight use; secure access improvements for all, particularly people with disabilities, as part of planning permissions for new developments, and ensures appropriate parking is provided to meet the essential needs of the development without impacting on the quality of the urban environment.

Hammersmith and Fulham Development Management Local Plan (July 2013)

Policy DM E1 Access to parks and open spaces

The Council will seek to reduce open space deficiency and to improve the quality of, and access to, existing open space. The Council will refuse development on open space that is not identified in the Core Strategy where such land whether on its own or cumulatively has local importance for its open character or as a sport, leisure or recreational facility, or for its contribution to local biodiversity or visual amenity. Unless the proposed development would release a site for built development needed to realise a qualitative gain for the local community in pursuance of other physical, social and economic objectives of the Core Strategy and provision is made for replacement of open space of equal or greater value elsewhere.

Policy DM E3 Nature Conservation

The policy seeks to protect nature conservation areas and green corridors from development likely to cause demonstrable harm to their ecological (habitats and species) value. In these areas, development will not be permitted unless: • the proposed development would release a site for built environment

needed to realize a qualitative gain for the local community in pursuance of other physical, social and economic regeneration objectives of the Core Strategy, and measures are included for the protection and enhancement of any substantive nature conservation interest that the site may have so that there is no net loss of habitat; or

• provision is made for replacement nature conservation interest of equal or greater value elsewhere in the locality.

Policy DM E4 Greening the borough

The council will seek to enhance biodiversity and green infrastructure in the borough by maximising the provision of gardens, garden space and soft landscaping and seeking green roofs and other planting as part of new development. The Policy will also seek to prevent the removal or mutilation of protected trees and seeking retention of existing trees and provision of new trees on development sites.




Policy DM G1 Design of New Build

Encourages a high standard of design and compatibility with the scale and character of existing development and its setting. The policy also ensures that all proposals are designed to respect the historical context and townscape setting of the site, and its sense of place.

Policy DM G7 Heritage and Conservation

The Council will aim to protect, restore or enhance the quality, character, appearance and setting of the borough’s conservation areas and its historic environment, including listed buildings, historic parks and gardens, buildings and artefacts of local importance and interest, archaeological priority areas and the scheduled ancient monument.

Policy DM H2 Promoting sustainable design and construction

The Council require the implementation of sustainable design and construction measures by requiring Sustainability Statements for all major developments to ensure the full range of sustainability measures have been taken into account during the design stage.

Policy DM H5 Sustainable Waste Management

All new developments should include suitable facilities for the management of waste generated by the development, including the collection and storage of separated waste and where feasible on-site energy recovery.

Policy H8 Air Quality The Council aim to reduce the potential adverse air quality impacts of new developments by implementing measures, including the requirement of all major developments to provide an air quality assessment that considers the potential impacts of pollution from the development on the site and on neighboring areas.

Policy DM H9 Noise The policy states that noise impacts of developments will be controlled by not permitting noise generating development, if it would be liable to materially increase the noise experienced by the occupants/users of existing or proposed noise sensitive users in the vicinity.

Policy DM J1 Transport Assessments and Travel Plans

The council will require a Transport Assessment, together with a Travel Plan where a development is expected to generate more than a specified number of trips, or during peak hours. Construction Logistics Plans and Delivery and Servicing Plans should be secured in line with TfL’s London Freight Plan and should be co-ordinated with Travel Plans.

Policy DMJ6 Borough road network – hierarchy of roads

Development which will have an effect on the borough’s road network will be regulated through the hierarchy of roads, which designates Hammersmith Road (A315) as a Local Distributor Roads. The Policy will not permit development if it would prejudice the effectiveness of these roads to distribute traffic to land and property within any local area bounded by the strategic route network and London Distributor roads, or introduce additional traffic on them.

APPENDIX 7 ENVIRONMENTAL APPRAISAL TABLES

St Paul’s Gardens - Appendix 7 Environmental Appraisal Tables Transport

Site Considerations Comments Mitigation required and Conclusions

Methodology A number of criteria are used when appraising the suitability of the site. These include access to the road network, which encompasses whether the site is considered to be accessible for HGVs, whether vehicles could potentially access and egress the site (allowing for mitigation / traffic management where appropriate) and the proximity to the Transport for London Road Network (TLRN). Other criteria include whether the site has good connections to public transport and the potential to utilise rail lines or river transport, as well as the availability of parking for the workforce, the extent of traffic management that would be required and the potential requirement to deliver mitigation. Taking account of these factors and using professional judgement, a balanced view is taken on the suitability of the site.

Access to road network

Access to the site would be taken from the A315 Hammersmith Road, travelling from the east and turning left into the site. Exiting the site, vehicles would turn left and head west along A315 Hammersmith Road.

The A315 Hammersmith Road connects to the A3220 in the east and the A4 in the west, which are both part of TfL’s TLRN.

The A315 Hammersmith Road is a busy four lane road which is suitable for HGVs. There are a number of pedestrian crossing points and sections of the road are reserved as bus lanes.

Bus stops opposite and immediately adjacent to the site access could potentially cause congestion if a bus was at the stop and a HGV was attempting to turn into the access.

The site is lit, there is a 30mph speed limit, visibility is good and footways are a good width. Current access to the site is very narrow and would be likely to require improvements to

Issue concerning the width of the access and its suitability for HGVs. The close proximity to a bus stop is also an issue, as vehicles attempting to turn into the site when there is a bus at the stop would cause congestion on Hammersmith Road, and restrict visibility to/from the access.

Transport


facilitate large vehicles.

It is currently anticipated that peak HGV movements during the construction period will be 140 per day. The implications of this level of movement are being investigated as part of the ongoing transport assessment.

Access to river

The site is not located in close proximity to the river.

The site is not considered suitable for barge transport by river.

Access to rail

The site is not located adjacent to a railway line. The site is not considered suitable for rail transport.

Parking

There is no parking available on the A315 Hammersmith Road.

Parking is available on Colet Gardens to the west of the site; however this is restricted to permit holders and pay-and-display with a maximum stay of four hours.

Parking is restricted within the vicinity of the site. Limited on street parking may be available for the workforce on Colet Gardens, however it is noted that this is a residential road.

Public transport accessibility

There are numerous bus stops along the A315 Hammersmith Road serving bus route numbers 9/10/27/391.

The site specific Public Transport Accessibility Level (PTAL) score is 6b, which is classified as excellent. The site therefore has excellent access to public transport, providing the potential for the workforce to access the site by public transport.

There is excellent access to public transport providing potential for the workforce to access the site by public transport.

Traffic Management To provide access from the A315 Hammersmith Road it is likely that a banksman or signals may

A traffic management plan should be submitted with any

Transport


need to be provided. Signing warning pedestrians of construction traffic would be required. It may be necessary to relocate/suspend the bus stop which is adjacent to the site access to prevent congestion. Size limits may also be necessary due to the width of the access.

proposal.

Summary:

Access to the site could potentially be provided from the existing access on the A315, Hammersmith Road. However, improvements such as widening will be required along with the provision of a banksman or signals. Liaison with the highway authority and Transport for London (TfL) should take place to determine the feasibility of the options. Currently, a peak of 140 HGV movements is anticipated per day. The implications of this are subject to further investigation as part of the ongoing transport assessment. No river or rail access is available within the vicinity of the site. There is no parking available on Hammersmith Road and limited parking is available within the vicinity of the site. The site features a high Public Transport Accessibility Level (PTAL) score indicating that staff will be able to access the site by public transport. On the basis of the information available it is considered that the site is suitable, as the road layout in the surrounding area is suitable for HGVs. The site would be subject to modifying the existing access and agreeing a traffic management strategy with the highway authority and TfL.

Noise


Methodology A noise model is used to predict the noise levels likely at the nearest sensitive receptor due to the noise emissions from the anticipated construction works equipment. This model is based on the methodology and information within BS 5228 -1:2009+A1:2014 ‘Code of practice for noise and vibration control on construction and open sites – Part 1: Noise’. When appraising the suitability of the site, a professional judgement is used by taking the predicted noise levels and the following factors into account: • Number of sensitive receptors in the vicinity of the site; • Whether there are sensitive receptors at higher floors; • Prevailing noise levels (taken from the DEFRA noise maps); • Potential for noise shielding from construction works; • Likely duration of construction works; • Whether there will be night-time working; and • Potential for locating noisy plant away from sensitive receptors.

Noise band level (from Defra noise maps)

Information from Defra noise maps indicates daytime road traffic noise levels of 65 to 70 dB(A) LAeq, at properties on Hammersmith Road, and 55 to 60 dB(A) LAeq at properties located elsewhere in the vicinity of the proposed site.

Not applicable.

Sensitive Receptors

To the east of the proposed site, there is a hotel located on the site boundary.

To the west of the site, beyond Colet Gardens there are approximately 20 two storey residential houses, and to the south is St. Paul’s Close which consists of 4 or 5 storey residential flats.

The nearest receptor is around 38m from the centre of the proposed site.

The site access route is proposed to be from Hammersmith Road. The traffic noise levels emitted by Hammersmith Road are already high, hence the access rout will minimise potential noise impacts due to construction traffic.

Not applicable.

Existing traffic issues Local road traffic, including the road traffic on Hammersmith Road to the north.

Not applicable.

Noise


Existing sources of significant noise emissions

According to the Defra noise maps the dominant source of noise in the vicinity is Hammersmith Road on the northern boundary.

Not applicable.

Predicted construction noise level at receptor

The construction noise levels at the most exposed receptor have been predicted using the methodology in BS 5228-1:2009+A1:2014 ‘Code of practice for noise and vibration control on construction and open sites – Part 1: Noise’. During the excavation of the shaft, the predicted noise level at the façade of the most exposed receptor is predicted to be 70 dB(A). It should be noted that the predicted noise levels are indicative only, for the purposes of comparison between the sites, and are based on an indicative distance between the centre of the site and the nearest receptor.

Not applicable.

NOAEL / LOAEL / SOAEL According to the criteria applied to the HS2 Environmental Impact Assessment for construction noise impacts, the Significant Observed Adverse Effect Level (SOAEL) is defined as ‘Noise outside dwellings from the Proposed Scheme at the facade: 75 dB (LpAeq,12hr) during the day; 65 dB (LpAeq,1hr) during the evening; or 55 dB (LpAeq,1hr) during the night, or above the existing ambient if this is higher.’ The predicted construction noise levels at the most exposed receptor do not exceed these criteria, which, according to the Explanatory Note to the Noise Policy Statement for England, indicates that exposure to these construction noise impacts will not result in ‘significant adverse effects on health and quality of life’.

Not applicable.

Noise


Potential issues

The construction period is estimated at a maximum of 3.5 years. The working hours for the works at surface level (site establishment, shaft sinking, finishings and demobilization) will be will be 12 hours (7am – 7pm) Monday to Friday, and 6 hours (7am – 1pm) on Saturday. This has the potential to result in adverse noise impacts to any sensitive receptors in close proximity to the site.

Working hours for the tunneling activities will be a worst case of 24 hours a day, 7 days a week. However, these activities will be underground, hence no adverse noise impacts due to these activities are anticipated.

A maximum of 140 HGV movements per day are anticipated. As the access route is directly off Hammersmith Road, significant effects due to road noise impacts are not anticipated.

The site area is bounded on three sides by sensitive receptors. Whilst the location of the shaft may be fixed, ancillary plant should be sited as far as is practicable from surrounding sensitive receptors.

The proposed acoustic building will provide useful noise mitigation to some plant and construction activities, however it will not provide any attenuation to equipment elsewhere on the site.

Vibration resulting from general construction works is not anticipated to result in an adverse impact. The nearest receptors to the centre of the site are at a distance of approximately 38m and it is unlikely that vibration levels will result in any damage during

Adherence to the good site practices provided in BS5228.

Siting of noisy equipment and construction activities as far as is practicable from sensitive receptors.

Provision of site boundary noise fences in addition to the proposed acoustic building.

Upgrading of the proposed acoustic building to improve noise attenuation performance, including use of sound insulating cladding and elimination of gaps/holes where possible.

Noise


shaft sinking, but may give rise to annoyance. Vibration from tunnelling should be considered on a case by case basis at particular sensitive locations.

Summary:

In terms of noise, this site is suitable due to the high ambient noise levels at the receptors in the vicinity of the site, and the potential to locate noisy equipment away from residential receptors. Substantial adverse effects are not predicted to be likely at the nearest noise sensitive receptors.

Water Resources - Hydrogeology


Methodology The appraisal refers to information on geology, hydrogeology, and source protection zones (SPZ), groundwater users, surface water bodies and wetland sites. It considers the below ground construction proposed at each site, in terms of depth and diameter and the method of installation. A conceptual model of the site is developed and the suitability of the site is appraised through assessing the possible mechanisms by which construction could influence the receptors identified.

Hydro-geological conditions

Geology (thickness)* • Made Ground (1.5m) • Superficial Deposits (Drift - alluvium and river

terrace deposits) (7m) • London Clay (75m) • Thanet Sand (8.1m) • Chalk (>85m) * Geology based on thicknesses from British Geological Survey borehole TQ27NW413 approx. 660m from the proposed shaft location. Hydrogeology • BGS mapping shows the site to be partially

underlain by a secondary A Superficial Deposits aquifer (alluvium and river terrace deposits) and partially by unproductive strata

• London Clay classified as unproductive strata or aquiclude***

• Chalk Formation classified as principal aquifer • Water level in the Superficial Deposits or upper

aquifer (where present)approximately 5.3mbgl (-0.3mAOD)**

• Water level in the London Clay (aquiclude) 2.5mbgl (2.6mAOD)**

• Based on limited data, the groundwater flow direction in the upper aquifer at this site is likely to be to the south west, towards the River

Excavations • Shaft One: 15mID, approx. 35m deep. • Tunnel to Lots Road: 3.5mID, assumed to be

35m deep. • Tunnel to Shepherds Bush area: 3.5mID,

assumed to be 35m deep.

Key points • Excavations would be founded in the London

Clay (aquiclude). • Water level in Superficial Deposits or upper

aquifer (where present) at least 29m above base of excavations.

• Water level in London Clay at least 33m above base of excavations.

• Significant thickness of the underlying London Clay (at least 75m).

• Excavations remain at least 57m above the top of the Chalk formation or lower aquifer.



Thames. ** Based on maximum water levels recorded in Thames Tunnel monitoring borehole PR1117 located at 0.8km south west of the site between Oct. 2009 to Dec. 2010** [nearest available data – may not be representative of site conditions] *** An aquiclude is an impermeable body of rock or stratum of sediment that acts as a barrier to the flow of groundwater.

SPZs and groundwater users

Source Protection Zone • Nearest SPZ is approximately 3.3km east-

north-east of the shaft location. EA Licensed groundwater abstractions • Licensed abstraction (TQ/23213/77988) 1km of

shaft location to southwest, used for non-evaporative cooling purposes.

• This borehole is licensed to abstract from the Chalk Formation.

Local Authorities (LA) unlicensed groundwater abstractions There are no unlicensed groundwater abstractors within 1km of the shaft location.

• Licensed abstraction 1km of shaft location. • No SPZs and unlicensed abstractions within

1km of the shaft location.

Borehole locations and depths

There are 13 historical records of water wells on BGS Geoindex within 1km of the shaft locations: 2 shallow well within the Superficial Deposits and 11 deep wells within the Chalk Formation.

• Licensed abstraction 1km from shaft location.

Potential impacts on groundwater (resources and quality)

Upper aquifer (where present) & aquiclude • Lowering of groundwater levels. • Reduction in yield at licensed abstraction. • Creation of pathway for pollution. • Obstruction to groundwater flows.

Upper aquifer (where present) & aquiclude • Sealing off upper aquifer & aquiclude by sheet

piling or similar. • Water management in line with Code of

Construction Practice.



• Groundwater flooding. • Seepage into and out of shaft. • Reduced water quality (turbidity). Lower aquifer None anticipated.

• Breaking out of sheet piling or piping through of flows at end of construction.

• Secondary lining of shaft. • Permeable materials placed around pipe works. • Quick setting grout products and approval by

Environment Agency. Lower aquifer None required.

Potential impacts on hydro-ecological features. (Note overlap with ecology)

There is a SSSI (Barn Elms Wetland Centre) located approximately 1.5km to the south-west. Please refer to ecological section for potentially sensitive ecological features.

• No SSSIs within 1km of shaft location.

Please refer to ecological section.

Potential issues Upper aquifer (where present) & aquiclude • Potential ingress of groundwater during

construction. • Potential management of contaminated/ poor

quality groundwater during construction. Lower aquifer None anticipated.

See above (likely types of mitigation measures that would be required).

Summary:

In terms of hydrogeology, this site is suitable because the shaft excavations would be constructed through the Superficial Deposits, which are partially classified as a secondary A aquifer and partially as unproductive strata, and would be founded in the London Clay Formation (aquiclude) and are not anticipated to extend into the Chalk Formation (lower aquifer), which is classified as a principal aquifer. The tunnel excavations would be through the London Clay Formation. Sheet piling is anticipated to be required to seal out the upper aquifer (where present) and seepages in the aquiclude. Therefore, no impacts on groundwater levels or flows are anticipated on the upper aquifer (where present). There is a licensed groundwater abstraction 1km from the shaft location which abstracts from the Chalk formation. The excavations are not anticipated to extend into the Chalk Formation (lower aquifer) and therefore no dewatering should be required. Therefore, no impacts on groundwater levels, flows or abstractions are anticipated on the lower aquifer. There are no unlicensed groundwater abstractors, Source Protection Zones or Sites



of Special Scientific Interest within 1km of the shaft location.

Water Resources - Surface Water & Flood Risk Assessment


Methodology The Environment Agency updated Flood Map for Surface Water and the Flood Map for Planning (Rivers and Sea) are used to determine the suitability of the site. The appraisal has regard to the level of risk of surface water flooding. It also considers if the site is located within the river channel and Flood Zone 3b, which would mean there is a direct pathway for pollution to the River Thames and any construction within the watercourse could potentially result in a displacement of flood water and impact on sediment erosion on the integrity of the flood defences.

Potential impacts on surface water features

The main site is located approximately 1.0km to the north east of the River Thames. It is considered that there is no direct pathway to the receptor due to the presence of defences on the River Thames and because of the distance between the site and receptor. The only pollution risk is through site drainage.

Work will need to be undertaken in consideration of Pollution Prevention Guidelines (PPG) – PPG1, PPG5 and PPG23.

Potential impacts on hydro-ecological features. (Note overlap with ecology)

None. None.

Surface Water Flood Risk According to the Environment Agency updated Flood Map for Surface Water, the site is shown to be at a ‘very low’ chance of flooding from surface water (<1 in 1,000 year event).

The existing site is a vegetated green space. Proposed construction will marginally increase the impermeable area of the site leading to a small increase in surface water runoff rates. Options for surface water mitigation should be considered for this site (i.e. Sustainable Drainage Systems) where space and land restraint allows, as required under the National Planning Policy Framework (NPPF), to ensure runoff rates from the site are similar to pre-construction runoff rates.

Flood Risk Zone

The site is located entirely within Flood Zone 1 (<1 in 1,000 year event). The area immediately surrounding the site is defended Flood Zone 2 (between 1 in 1,000 and 1 in 100 year event); however it is in an area which benefits from the

If the site is over 1ha then a Flood Risk Assessment will be required in accordance with the NPPF.

Water Resources - Surface Water & Flood Risk Assessment


Tidal River Thames flood defences which protect up to the 1,000 year flood event. Therefore, the area surrounding the site is defended and only considered to be at a residual risk of tidal flooding from the Tidal River Thames flood defences as a result of a potential breach or overtopping of the defences. Sewage transmission infrastructure is considered to be water compatible according to Table 2 of the Planning Practice Guidance for Flood Risk and Coastal Change.

Potential issues None. None. Summary: In terms of surface water resources, this site is suitable because there is no direct pathway for pollution to be transmitted to the nearest surface water receptor. In terms of flood risk, the site is suitable as it is defended from flooding from the River Thames and is at very low risk of flooding from surface water.

Air Quality


Methodology The appraisal considers potential dust impacts using a qualitative risk assessment which is based on the Institute of Air Quality Management (IAQM) Guidance for assessing impacts from construction activities. In this approach the risks of dust generation are considered for sensitive locations around a construction site and for the following activities: Demolition; Earthworks, including handling, working and storage of materials; Construction activities; and the Track-out (the transfer of dust making materials from the site onto the local road network).

Air Quality Management Area (AQMA)

A borough wide AQMA has been declared for NO2 and PM10.

There is a need for more site specific data.

Sensitive Receptors

There are between 10 and 100 residential receptors located along Colet Gardens and More Close which are less than 20 metres away from the site boundary. Larmenier and Sacred Heart Catholic Primary School is also located 155 metres north of the site, and Ealing, Hammersmith and West London College located 90 metres south east of the site.

There are relevant air quality sensitive receptors present along the route that the construction traffic is likely to take and also close to the proposed construction works.

Existing traffic issues The main traffic issue in this area is exhaust emissions from the A315 Hammersmith Road, which is located 20 metres to the north of the site construction works.

Additional vehicle emissions have a high potential to interfere with local air quality action plan policies due to current exceedances of the Air Quality Objective in the vicinity of the site.

Existing sources of significant air pollutants

Main sources of nitrogen oxides and small particle emissions in the area are road traffic, domestic and commercial gas boilers, and small industrial processes.

See above.

Notable gaps in existing air quality monitoring

The nearest available diffusion tube data is 330 metres from the site and indicated that the air quality objective value for NO2 is exceeded in the area. This site is located adjacent to the A4 Talgarth Road.

Collect a minimum of 6 months diffusion tube data at the site access/egress or other point of access to the major road network. Additionally, hyrdrogen sulphide sampling has been

Air Quality


proposed as an equipment requirement for each of the schemes.

Potential issues

The risk from additional exhaust emissions from construction HGVs is undefined at present. There is the potential for additional exhaust emissions due to traffic management required for the construction of the shaft and tunnels are undefined at present. The construction period is approximately 3 to 3.5 years in duration. There are no ecologically sensitive receptors within 50 metres of the site. The potential for adverse impacts due to the construction phase of the assessment are defined below following the IAQM (2014) construction dust guidance. Demolition The site consists of St Paul’s Garden and open space which includes areas of grass, paths, trees and planting, therefore there will be limited demolition on the site. Some limited removal of the boundary walls may be required to enable access and egress from the site. Earthworks As the total area of the site is less than 2,500m2 threshold, a small dust emission magnitude is likely as a result of potential earthworks at the site. There

Minimise HGV movements on the local road network during the peak hour. Local residents should be informed in advance of the proposed works with an explanation that dust deposits over the 3 to 3.5 year construction period would be non-hazardous. Residents should be provided with contact details to use should they have any concerns. Standard dust control measures will minimise any effects of fugitive dust on nearby sensitive receptors Odour control measures will be required during the operation of the site, and may take the form of either active or passive methods. The exact form of control required will be determined at a later date.

Air Quality


are between 10 and 100 residential properties within 20 metres of the earthworks. Therefore the dust soiling effects for earthworks is assessed as high, without mitigation (IAQM, 2014). There are between 10 and 100 residential properties within 20m of the proposed earthworks, annual mean PM10 background concentrations at the site are currently between 24 and 28 µg/m3, which is well below the air quality objective. Sensitivity of the area to human health impacts due to earthworks is therefore high. Construction As the total volume of the site is less than 25,000m3 threshold, a small dust emission magnitude is likely as a result of potential construction at the site. There are between 10 and 100 residential properties within 20 metres of the construction works. Therefore the dust soiling effects for construction is assessed as high. It is proposed that a conveyor will be used and will run to an approximately 8 metre high discharge over a spoil bin. Dropping material from such a height could generate dust and adversely affect the residential properties in the vicinity of the area. This impact can be reduced by covering the conveyor and minimising the drop height. There are between 10 and 100 residential properties within 20 metres of the proposed construction works, annual mean PM10 background concentrations are

Air Quality


currently between 24 and 28 µg/m3, which is well below the air quality objective. The sensitivity of the area to human health impacts due to construction is therefore high. Track-out The following HGV numbers are discussed in terms of (IAQM) Guidance for assessing impacts from construction activities. The proposed number of Heavy Duty Vehicles (HDV) (equivalent of HGV) movements per day varies throughout the construction programme from less than 10, between 10 and 50 and more than 50. This would result in a small, medium and large dust emission magnitude respectively. As there is more than one office within 20 metres of the track-out routes along Hammersmith Road sensitivity of the area around the proposed site to dust soiling effects is considered a medium risk. There is more than one office within 20m of the proposed track-out route along Hammersmith Road, annual mean PM10 background concentrations at the site are currently between 24 and 28 µg/m3, which is well below the air quality objective. Sensitivity of the area to human health impacts due to track-out is therefore high.

Summary: The construction phase is approximately 3 to 3.5 years, and the construction site is classified as ‘small’ using the IAQM (2014) construction dust guidance. However, the sensitivity of the area to dust soiling effects associated with construction, earthworks and track-out is high to medium. Using the same methodology, the sensitivity of the area to human health impacts associated with construction works, earthworks and track-out is high. With standard dust control measures in place the risk of impacts on sensitive receptors can be reduced, but additional site specific measures are also likely

Air Quality


to be required, such as ensuring vehicles entering and exiting the site are covered to prevent escape of materials during transport.

There is potential for HGV movements on the local road network to cause localised air quality impacts in area of already poor air quality. This can be somewhat mitigated by minimising the movement of HGVs during peak hours.

In summary this site is considered less suitable because the sensitivity of the area to dust soiling effects associated with construction, earthworks and track-out is high to medium. There is also the potential for additional exhaust emissions due to traffic management required for the construction of the shaft and tunnels to cause localised air quality impacts; these impacts are undefined at present. As described above, it is likely it would require additional site specific mitigation beyond standard mitigation measures if selected to make it suitable.

Archaeology


Methodology The appraisal uses current Greater London Historic Environment Record (GLHER) point data. The proximity of Archaeological Priority Areas and Conservation Areas is considered and the GLHER record for each receptor within 100m of the proposed site is accessed and interpreted in terms of ‘very high or high’, ‘medium’ or ‘other’ importance. When appraising the suitability of the site, the potential for receptors to extend to within the proposed site is considered. Historic OS mapping (limited to 19th and 20th century origin) is also inspected with a summary of recent historical uses provided to indicate the potential for previous on-site disturbance.

Designations, including Archaeological Priority Areas

The site is not within an Archaeological Priority Area. The site is not within a Conservation Area but lies on the boundary of Brook Green Conservation Area which is directly north, and Gunter Estate Conservation Area which is directly east.

Not applicable.

Summary of historical uses

The earliest available OS map dates to 1873 and shows the site as open field immediately to the south of the established Hammersmith Road. In 1896 a large school (St Paul’s) has been built immediately outside of the southern boundary of the site. The school is demolished by the early 1970’s.

Not applicable.

Potential receptors of very high or high value with the potential to be directly affected

There are no recorded archaeological receptors. This does not preclude the possibility of their existence.

Not applicable.

Potential receptors of medium value with the potential to be directly affected

There are no recorded archaeological receptors. This does not preclude the possibility of their existence.

Not applicable.

Other receptors with the potential to be directly affected

There is a record for a find spot of post medieval date to the south of the site (MLO4351).

Not applicable.

Extent of existing disturbance (if known) The site was the former location of a playing field of St Paul’s School. It is currently a park and there is no clear evidence for disturbance.

Not applicable.

Potential issues

Archaeological remains may exist at the site at depth. There is the potential that ground work excavations could disturb preserved material that pre-dates the establishment of St

The site of the school has recently been investigated (ELO3017) but it has not been possible to assess this information

Archaeology


Paul’s School playing fields in the mid-19th century. There is the possibility that remains of post medieval or medieval date exist below ground.

at this stage. In consultation with the Borough Archaeologist, further information (such as a desk based assessment) may be required to support a planning application.

Summary:

There is evidence for post medieval archaeology in the vicinity of the site but this is likely to be of low significance. There is also the possibility of below ground remains associated with medieval occupation in the area to be present within the site. On the basis of the information provided it is considered that the site is suitable because there are unlikely to be any archaeological remains present that will represent a constraint.

Built Heritage


Methodology The appraisal uses current Greater London Historic Environment Record (GLHER) point data. The proximity of Conservation Areas, Listed Buildings and Registered Parks and Gardens is stated and the GLHER record for each receptor within 250m of the proposed site with the potential to be directly affected is accessed and interpreted in terms of its importance. When appraising the suitability of the site, potential impacts on the significance of Conservation Areas are considered, alongside any potential perceived or direct impacts on Listed Buildings and their associated curtilage structure or the historic setting of a Listed Building.

Designations including Conservation Areas, including trees

Listed Buildings

Masters Lodge and Porters Lodge, Boundary Walls and Circular Garden Building to St. Paul’s School (Grade II) – site is located within the listed boundary walls and adjacent to the Lodges and Garden Building.

Colet Court School (Grade II) - 40m north.

St Joseph’s Alms houses (Grade II) - 97 m north.

Church of Holy Trinity (Grade II*) - 145 m north.

Conservation Areas

The site is not within a conservation area but lies on the boundary of Brook Green Conservation Area which is directly north and Gunter Estate Conservation Area which is directly east.

The Dorcas Estate Conservation Area and Fitzgeorge & Fitzjames Conservation Areas are within 250m of the site to the east.

See below.

Built Heritage


Registered Parks and Gardens

There are no registered parks and gardens within 250m.

Potential receptors of medium to very high importance with the potential to be directly affected

The Grade II listed Masters Lodge and Porters Lodge, Boundary Walls and Circular Garden Building to St. Paul’s School will be directly impacted by the proposals, by developing within the listed boundary walls, and potentially damaging part of this structure to enable access and egress from the site. The permanent elements, and the temporary construction structures, would have an impact on the significance of the grade II listed structures as a result of development within their setting.

There may be a potential impact on the significance of the Grade II listed Colet Court School (located across Hammersmith road c. 40m to the north of the site) and the Grade II listed St Joseph’s Alms Houses (located 97 m to the north) as a result of development within their setting.

The permanent elements, and the temporary construction structures, could have an adverse impact on the Gunter Estate and Brook Green Conservation Areas. These impacts would primarily derive from the cranes and welfare and office units during the construction phase.

Damage to the Grade II listed Boundary Walls adjoining Masters Lodge and Porters Lodge should be avoided during the construction and operation phases. Listed building consent will be required for this development. This impact could potentially be mitigated by considering relocating the proposed entrances to the western boundary wall of the former St. Paul’s School, which is constructed of plain brick only, unlike the more ornate northern wall with its iron railings, and could be reinstated following the construction phase.

High-quality design and careful location of the above-ground elements, to allow the completed project to be incorporated into the existing garden.

Retention or reinstatement of as much of the trees and shrubs and green space as is possible is recommended in order to preserve the character of the garden and boundary area.

Other receptors of lesser importance with the potential to be directly affected

None. Not Applicable.

Built Heritage


Particular considerations on sites where new permanent structures are required

Permanent development within the site has the potential to impact on Gunter Estate Conservation Area and Brook Green Common Conservation Area, and three grade II listed buildings, primarily the Masters Lodge and Porters Lodge, Boundary Walls and Circular Garden Building to St, Paul’s School. However, the potential impact of the permanent elements will be less than that associated with the temporary structures.

High-quality design and careful siting of the relatively minor permanent elements may be required to minimise any potential long-term impacts.

Potential issues The potential impact on the Grade II listed Masters Lodge and Porters Lodge, Boundary Walls and Circular Garden Building to St. Paul’s School will require further assessment work for any potential development.

The development proposals may also have an impact on the significance of the Grade II listed Colet Court School, the Grade II listed St Joseph’s Alms Houses, and of the Gunter Estate and Brook Green Conservation Areas. These impacts would primarily be as a result of the temporary development structures within their setting.

The mitigation described above may reduce the impacts somewhat, but they will not completely mitigate them, and there will be an impact on the Grade II listed Masters Lodge and Porters Lodge, Boundary Walls and Circular Garden Building as a result of the proposals. Listed building consent will be required. Use of hoardings during the construction period is not considered to alter the impact of the proposals on the designated heritage assets during this period.

Summary: The site is not located within a Conservation Area. However, the Brook Green and Gunter Estate Conservation Areas and two further grade II listed buildings/structures are located in close proximity (Colet Court School and St. Joseph’s Alms Houses). There may be a potential impact upon these grade II listed structures and the two Conservation Areas, resulting from development within their setting. However, given the local precedent of modern development and the resulting change in character of the immediate environs, the presence of these built heritage assets should not

Built Heritage


represent a constraint. A grade II listed structure (Masters Lodge and Porters Lodge, Boundary Walls and Circular Garden Building to St. Paul’s School) is located within the site itself and may be directly impacted. The site has historic value as the site of the former St Paul’s School, designed by Alfred Waterhouse. The grade II listed Masters Lodge and Porters Lodge are still located immediately to the east, and the Circular Garden Building and the Boundary Walls and railings within the site (which are part of the listing) are still present. The potential physical impact upon them, and impacts upon their significance as a result of development within their setting will need detailed assessment, and listed building consent would be required.

On this basis it is considered that the option currently proposed for this site is less suitable.

Townscape and Views


Methodology The methodology used is based broadly on guidance within the Guidelines for Landscape and Visual Impact Assessment 3rd Edition (LI and IEMA 2013). Based on the nature of the proposed development, each site is appraised against its sensitivity to changes in townscape character and visual amenity. The sensitivity of townscape resources is determined by features such as Conservation Areas, trees and the quality of the space. Visual receptors are considered in relation to the type and activity of the viewer. Where the development could potentially involve the loss of mature trees, which could not be replaced in the short term, a time element has been considered to assist in appraising the suitability of the site.

Designations (including TPOs, Registered Historic Parks and Gardens and Protected Views)

There are no Registered Historic Parks and Gardens within 250m of the site.

The site is located within St Paul’s Gardens, which has been designated open space by the London Borough of Hammersmith and Fulham. St Mary’s Churchyard is located adjacent to the site.

The site is not within a Conservation Area but lies on the boundary of Brook Green Conservation Area which is directly north, and Gunter Estate Conservation Area which is directly east. The Dorcas Estate Conservation Area and Fitzgeorge & Fitzjames Conservation Areas are within 250m of the site to the east.

Trees on the site may be protected by Tree Preservation Orders (TPOs) and enquiries with the London Borough of Hammersmith and Fulham would be required.

There are important views into, out of, and within the Brook Green Conservation Area, however, these

There would be an adverse effect on St Paul’s Gardens open space.

Townscape and Views


would not be effected by the scheme.

Townscape The site is located in the Hammersmith area of West London. It is a public open space with a boundary wall and fence on all sides. The site comprises amenity grass, shrubs and herbaceous planting, mature trees, footpaths, and an old kiln building. Mature boundary vegetation and trees within the open space create a sense of enclosure and separation from the busy city life outside, although traffic noise from Hammersmith Road on the northern boundary has a noticeable impact on the tranquility of the open space.

The presence and operation of machinery, material stores and buildings would not be in keeping with the existing character of the area and would have a temporary, direct, adverse impact. Site clearance would involve the removal of mature trees that would have an adverse impact on the character of the open space. Hammersmith Road is a busy urban road and the indirect effect of construction traffic on neighbouring areas would be unlikely to be major.

Permanent elements once the scheme is operational would include the retention of the shaft, with periodic access required for maintenance, a small control building, and a series of odour control stacks and equipment up to 15m in height. These stacks would be noticeably out of character with the open space. The

Hoarding should be used around the site to minimise townscape impacts during construction. Careful design and siting of the permanent elements would help to minimise long-term impacts. Mature trees adjacent to and within the site should be protected and retained during the works in line with BS5837. The impact of the loss of any mature trees that might have to be removed could not be easily mitigated.

The site is less suitable, because the scheme would involve the loss of mature trees that could not be easily mitigated. However, the boundary vegetation that gives the site its enclosed feel and sense of separation could be retained. There would be temporary adverse impacts during construction.

Townscape and Views


loss of mature trees would have a long-term adverse impact on the character of the open space.

Views Railings and boundary vegetation limit views into the open space during summer, however there may be more open views during winter. There are very few views in from outside the site, except at entrance points and from the upper storeys of nearby office buildings to the north. There are open views of the site from St Paul’s Hotel on the eastern boundary. From within the park, views are mostly of the interior of the park. From outside the park, views are mostly of the edge of the park, with no views of the interior.

Construction activity and machinery would be out of character with existing views of the site. There would be temporary (3 to 3.5 years) adverse impacts. Views would be mainly restricted to the access points, the adjacent hotel, and the upper storeys of nearby offices.

Permanent elements may be prominent from the area immediately surrounding the site, notably the stacks and other odour control equipment. These elements would have an adverse impact on views within the site. The loss of mature trees would have a long-term adverse impact on visual amenity.

During construction the use of hoardings and appropriate lighting would help minimise the visual impact. Retaining mature trees and vegetation around the boundary of St Paul’s Gardens would filter views of construction activities, however there would be clear views from the hotel on the eastern boundary. The design and location of permanent structures should be given careful consideration within an overall landscape scheme to protect long-term visual amenity.

The site is less suitable as in the long-term, visual amenity within the park would be adversely impacted by the presence of the odour control stacks and equipment. There would be a temporary adverse impact on views from the adjacent hotel for the duration of construction.

Photograph

Townscape and Views


View across St Paul’s Gardens at Hammersmith Road towards St Paul’s Hotel.

Comments in relation to the site layout Retain as much boundary vegetation and mature trees within the site, as possible. Careful design and siting of the permanent elements would help to minimise long-term impacts.

After use of the site Introduce an appropriate landscape scheme to integrate the permanent elements into St Paul’s Gardens, and restore the land following construction activity.

Summary:

During construction, there would be temporary adverse townscape and visual impacts, with temporary adverse impacts on views from the adjacent hotel. Mature trees should be retained on site as far as possible.

In the long-term, visual amenity within the park would be adversely impacted by the presence of the permanent elements such as the odour control stacks and equipment. Therefore, it is considered that the site is less suitable. The careful design and location of the permanent elements within an appropriate landscape scheme would minimise potential long-term impacts on St Paul’s Gardens.

Ecology (terrestrial and aquatic)


Methodology The ecological appraisal consists of a desk top study to identify habitats within and adjacent to the site. This includes a review of aerial photography and photographs taken within the site to determine habitats present and the potential for these habitats to support protected and/or notable species. Greenspace Information for Greater London (GIGL) data is used to search for records of Biodiversity Action Plan (BAP) Priority habitats, Sites of Importance for Nature Conservation (SINC) and records of protected and/or notable species within a 2km radius of the site. Natural England’s MAGIC website is also consulted to determine proximity to Statutory Designated sites (i.e. Sites of Special Scientific Interest and Local Nature Reserves).

From reviewing the imagery, the GIGL data search and the MAGIC website, a judgement is made on the potential for the site to support protected and/or notable species and/or habitats. On this basis, the site is appraised in terms of its suitability.

Statutory designations

Barn Elms Wetland Centre Site of Special Scientific Interest (SSSI) lies 1.5km south west of the site.

None required.

Non-statutory designated wildlife sites St Paul’s Open Space Site of Local Importance (SLI) ~ within the site

Hammersmith Cemetery SLI ~ 0.3km S

West London and District Lines Site of Borough Importance (SBI) Grade 1 ~0.5km NE

Loris Road Community Garden SLI ~ 0.8km NW

Disused Trackbed West of Hammersmith SBI Grade 1 ~ 0.8km W

Normand Park SLI ~ 1.km SE

Holland Park Site of Metropolitan Importance (SMI) ~ 1km NE

River Thames and Tidal Tributaries SMI ~ 1km SW

Standard construction practices for avoidance of pollution (e.g. dusts) are required.



Furnivall Gardens SLI ~ 1.1km W

Fulham Cemetery SLI ~ 1.2km S

Shepherds Bush Green SLI ~1.2km N

West London Line South of Earl’s Court SBI Grade 1 ~ 1.4km SE

Ravenscroft park SBI Grade 2 ~ 1.4km W

Brompton Cemetery SBI Grade 1 ~ 1.5km SE

The Wetland Centre SMI ~ 1.5km SW

Cathnor Park SLI ~ 1.6km NW

Godolphin Road Community Garden SLI ~ 1.6km NW

Ladbrooke Grove Gardens Complex SBI Grade 2 ~ 1.8km NE

Avondale Park Wildlife Garden SLI ~ 1.8km N

Hammersmith Park SBI Grade 2 ~ 1.9km N

District Line north of Fulham Broadway SBI Grade 1 ~ 1.9km SE

Biodiversity Action Plan (BAP) priority habitats

The data search identified that the site comprises London BAP habitat ‘Parks and Urban Greenspaces’ known as Hammersmith Road Open Space.

There are a large number of additional BAP Priority habitats within 2km of the site. These include: acid grassland,

Loss of BAP habitat may require limited compensatory provision, particularly if permanent land take occurs.



heathland, park and urban greenspaces, standing water, tidal Thames, wasteland and woodland.

Protected or otherwise notable species within the Study Area

Protected species within 2km of the site: Birds: Black redstart, whooper swan, bittern ruff, Mediterranean Gull, fieldfare, redwing, firecrest, brambling, common crossbill, black-necked grebe, hobby, peregrine falcon, little ringed plover, turtle dove, and marsh warbler. Reptiles: Grass snake

Bats: serotine, Daubenton’s, noctule, Leisler’s, common pipistrelle, soprano pipistrelle, Nathusius’s pipistrelle, brown long-eared bat

Invertebrates: Stag beetle Lucanus cervus ~ 0.5km SW

Notable species within 2km of the site: Herring gull Larus argentatus (london BAP), common startling Sturnus vulgaris (London BAP), house sparrow Passer domesticus (London & UK BAP), hedge accentor Prunella modularis (London BAP), song thrush Turdus philomelos (London BAP), brindled beauty Lycia hirtaria (UK and London BAP, white ermine Spilosoma lubricipeda (UK and London BAP), brown-spot pinion Agrochola litura (UK and London BAP).

Ecological assessment of trees and adjacent buildings to assess potential to support bats. Ecological assessment for the presence of dead wood both above ground and the potential for buried dead wood which may be used by stag beetles.

Potential issues

A number of mature trees are present on the site (including London Plane Platanus × acerifolia). A small round tiled building (the old kiln) is present within the site. These may have potential to support roosting bats. Without further

Ecological assessment of trees and the building to determine if further bat surveys are required.



inspection the presence of bat roosts within the site cannot be discounted.

Features present on site and adjacent habitats have potential to support foraging and commuting bats.

Trees, shrub vegetation and the old kiln building present within the site have potential to support nesting birds during the breeding season.

The shaft in the south of the site has the potential to cause severance of roots of mature trees. In addition the entrance and exit to the north of the site has potential to damage tree roots via compression from traffic. A number of temporary structures also appear to be located beneath tree canopies. As such, there is potential for compaction to tree roots from increased weight and also damage to the tree canopy.

Bat activity surveys to determine the species and numbers of bats foraging and / or commuting within the site.

Works should commence outside of the nesting bird season (nesting bird season is between March and September). If works are to commence during the nesting birds season, then vegetation should be checked by an ecologist for nesting activity immediately prior to the commencement of any works. If nesting birds are identified, a suitable buffer will need to be retained until after all chicks have fledged.

Ensure that root protection zones are observed and that tree canopies remain undamaged.

Summary:

St Paul’s Open Space Site of Local Importance (SLI) is located within the site. In addition there are 20 other Sites of Importance for Nature Conservation (SINC) within the surrounding 2km of the site. The next closest SINC is Hammersmith Cemetery SLI which is located 0.3km south of the site. There are a number of records of protected species within 2km of the proposed site. These are for: eight species of bat (the closest record is for common and soprano pipistrelle, each 0.4km south east of the site), stag beetle (the closest record 0.5km south west of the site), 16 species of protected bird (the closest record is for fieldfare 0.4km north east of the site), one species of common reptile (grass snake) located 1.9km from the site, and a number of notable species of bird and terrestrial invertebrate. The data search identified that the site comprises London Biodiversity Action Plan (BAP) habitat ‘Parks and Urban Greenspaces’.

Ecological assessment for the presence of dead wood which might be used by stag beetles is recommended. An ecological inspection of trees, the old kiln building and other habitats on site is recommended to assess bat roost potential and nesting bird potential. Bat activity surveys are recommended to determine the use of the site by commuting and foraging bats.

The site is less suitable because the site is identified as St Paul’s Open Space SLI and, in addition, habitats within the site are listed as the London



BAP habitat ‘Parks and Urban Greenspaces’. If this habitat is lost or degraded, compensatory provision may be required to enable works to proceed within the site. The site has potential to support protected species such as bats, stag beetles and nesting birds. If any of these species are identified to be utilising habitats to be impacted upon by proposed works within the site, avoidance and mitigation measures will be required.

Land Quality

Methodology A concise summary of desktop study information including review of; current and historic land uses, geology, hydrogeology and hydrology, registered pollution incidents and contemporary trade entries is provided. A Conceptual Site Model (CSM) identifying potential pollutant-pathway-receptor linkages is used to assess potential contamination risks that could impact on the proposed development. A “Contamination Category” consisting of Category 1 (low risk) sites, Category 2 (medium risk) sites and Category 3 (high risk) sites, is assigned based on the level of risk and subsequently used to appraise the suitability of the site.

Site Location St Paul’s Gardens.

Current Site Use Garden and public open space.

Topography Generally flat.

Field Evidence of contamination (i.e. visual/olfactory)

Desk based assessment only.

Current surrounding land use (immediately adjacent to site)

Main road (Hammersmith Road - A315), mixed commercial (office, shops and services) and residential.

Immediately to the east of the site is No. 153 Hammersmith Road which is occupied by a building Listed as Grade II (Masters Lodge and Porters Lodge of St Paul’s School). This building has been converted into a 35 bed hotel.

Beyond 153 Hammersmith Road to the east is an office block and a church with grounds that extend to boundary of St Paul’s Garden and open space. Immediately to the south of the site, along More Close / Lily Close and to the east of the site along Colet Gardens, are residential properties. Opposite the site along Hammersmith Road are office buildings.

Geological and Hydro geological Information

Geological Strata • Made Ground (1.5m) • Superficial Deposits (Drift - alluvium and river terrace deposits) (7m) • London Clay (75m) • Thanet Sand (8.1m) • Chalk (>85m) * Geology based on thicknesses from British Geological Survey borehole TQ27NW413 approx. 660m from the proposed shaft location.

Land Quality

The south-eastern corner of the site is also underlain by Superficial Deposits of the Langley Silt Member. Underlying Aquifer Classes The site overlies Superficial Deposits (upper aquifer) which are defined as a Secondary A Aquifer.

Groundwater Vulnerability / Soil Classification (High / Intermediate / Low / Not Applicable)

The site is mainly underlain by Superficial Deposits (Upper Aquifer) which are defined as a Secondary A Aquifer with soils with a high leaching potential. In the south-eastern corner, the site is underlain by Unproductive Strata with soils with a low leaching potential.

Source Protection Zone Details The site is not located within a groundwater Source Protection Zone

Surface Water Receptor The nearest surface water receptor is the River Thames, which is approximately 1.0km to the south-west of the site

Registered Abstraction Points No groundwater or surface water abstractions are recorded within 250m of the site

Relevant Information within a 250m radius of the site

Historical Potentially Contaminating Activities (based on mapping data)

Onsite 1873 map – The site is established within an area of open land, with Hammersmith Road to the north and Colet Garden to the west. 1896 map – St. Paul’s School is located to the south of the site. The site is developed into the school gardens, with walkways and trees. The gardens were generally remained unchanged between 1896 and 1940 until they were redesigned in 1955.. 1975 map – St Paul’s School is dismantled. A street, labelled More Close, is present to the south of the site, with residential properties behind. Today, the site consists of an area of open space named St Paul’s Garden, which includes areas of grass, paths, trees and planting. Offsite In 1873, housing is developed 50m to the east of the site, Hammersmith Road to the north, Colet Gardens to

Land Quality

the west and an open land to the south.

By 1896, St. Paul School is developed to the south. There is a railway line approximately 250m to the south of the site. Hammersmith station is located approximately 370m west.

By 1955, a factory labelled Cadby Hall (a piano factory) is located 50m north-east of the site. By 1940, the open land to the south has become a ‘recreation ground’ and by 1975 the St. Paul’s School is dismantled.

By 1987, the recreation ground to the south has become a residential area with a college.

There is little change to the area from 1987 to the present day; there are hotels, schools, shops and services for local residents in the immediate surroundings.

Pollution Controls There is one Local Authority Pollution Prevention and Control: Violet Super Dry Cleaners, 106-108 Hammersmith Road, London, W6 7JP, 13th June 2007, permitted, Dry Cleaners 50m north-west.

Landfill Sites There are no recorded historic or current landfill sites within 250m

Registered Waste Licenses There are no registered waste licenses within 250m

Registered Radioactive Substances There are no registered radioactive substance sites within 250m

Fuel Stations/Depots There are no fuel stations / depots within 250m

Contemporary Trade Entries • Oil companies (37m west – active) • Garage services (70m west – inactive) • Dry cleaners (135m west – active) • Refrigerators and Freezers servicing and repairs (135m west – inactive) • Cleaning services (135m west – inactive) • Waste disposal services (250m west – inactive) • Diesel engine equipment and services (54m south – active) • Oil fuel distributors (131m east – inactive) • Bus & coach operators and stations (27.6m north – inactive)

Land Quality

Site Classification Based on Above Information

Activity Distance and Direction to Site Contaminants

Potential Site Contaminants derived from surface sources (e.g. contaminants in Made Ground)

1) Although the site is a public open space, potential for Made Ground from historic development onsite may still exist and there has been historic development adjacent to the site.

1) Onsite and directly adjacent to site.

1) Metals, PAHs, TPH.

Potential Site Contaminants derived from off-site sources and transported to site

1) Former piano factory.

2) Garage Services.

1) 50m north east of site.

2) 70m west of the site.



Potential Contamination Pathways to Site (Conceptual Site Model)1

Source 1 – A1, A2, A3, B4, C5. Source 2 – E1

Contamination Category Category 1 (low-risk)

Conclusion: On the basis of the information available, it is considered that the site is suitable. The site has not been previously developed and has been open space (St Paul’s Gardens) since the earliest map reviewed. The 1873 map shows the site as an open field immediately to the south of the established Hammersmith Road. The surrounding land has not included activities or uses that are considered to represent a substantial risk of ground contamination at the site. Therefore, the likelihood of contamination at the site is considered to be low.

Notes:

1. Refer to schematic Conceptual Site Model for explanation of site-specific source-pathway-receptors.