PEIR Non-Technical Summary Part2

8/3/2019 PEIR Non-Technical Summary Part2

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Section 9: Putney Bridge Foreshore

Preliminary environmental information report Page 84 Non technical summary

Figure 9.6 Aquatic ecology data gathering at Putney BridgeForeshore

9.7 Ecology terrestrial

9.7.1 The majority of the site lies within the River Thames and Tidal TributariesSite of Importance. There are mature trees on and adjacent to the site.The foreshore and adjacent trees are of value to commuting and foragingbats. The trees provide nesting habitat for common bird species. Theforeshore is likely to be of value to wintering birds and this will be reportedin the Environmental Statement following the completion of surveys.

9.7.2 No significant effects on designated sites are anticipated duringconstruction (aquatic ecology effects are considered in section 6.6).

9.7.3 The effect on habitats from the pruning of adjacent trees would not giverise to significant effects. Displacement of breeding birds from trees onsite is likely to have a site level adverse effect. Displacement from treesadjacent to the site would give rise to negligible effects. Site clearanceand construction activities would result in site level adverse effects forforaging and commuting bats due to disturbance and habitat loss.Disturbance to bats from lighting would be negligible. Effects on winteringbirds will be assessed and reported in the Environmental Statement.

9.7.4 Operational activity would be limited to occasional maintenance work,which is considered unlikely to have significant effects on terrestrialecology.

9.7.5 In addition to measures included within the Code of Construction Practice,further mitigation, such as habitat creation will be developed as necessary.


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9.8 Historic environment

9.8.1 The site comprises part of the south bank of the Thames foreshore andPutney Embankment river wall, and includes a late 19th- draw dock andcobbled slipway. The site lies within the Putney Embankment

Conservation Area and the eastern edge of the site runs beneath theGrade II listed Putney Bridge where two late 19th-century Bazalgettescreens to the sewer outfall are located (Figure 9.7). The site also includesa group of Grade II listed bollards. These designated heritage assets areall of high asset significance. Listed buildings in the vicinity include theGrade Il listed White Lion Hotel 40m to the south and the Grade II* Churchof St Mary the Virgin 20m to the southeast.

9.8.2 The site lies within a locally designated Archaeological Priority Area andthe main potential is for post-medieval remains of barge beds, flooddefences and construction debris associated with Putney Bridge, whichwould be of medium asset significance. Post-medieval foreshore silts,

isolated pottery and building materials might also be present. The remainsof medieval revetments or other riverfront structures would be of low ormedium heritage asset significance. Medieval or post-medievalconstruction debris and isolated artefacts would be of low heritage assetsignificance. The potential for palaeoenvironmental remains (e.g. organicremains such as pollens or plant fossils) and buried assets of earlierperiods is considered to be low due to probable past scouring from riverflows.

9.8.3 Construction works would involve removal of the existing sewer outfallsthat form part of Putney Bridge, resulting in a major adverse effect. There

would be no other direct effects on the bridge itself. The cobbled slipwaywould temporarily be taken out of use, with some localised removal ofcobble stones, resulting in a minor adverse effect. Construction workswould entail deep excavations which would entirely remove archaeologicalassets within the construction footprint. If such assets were present, thiswould comprise a high magnitude of impact and would give rise to a minoror moderate effect on the remains of medieval or post-medievalrevetments or riverside structures, and a minor adverse effect on isolatedartefacts.

9.8.4 The effects on the sewer outfalls and slipway would be mitigated through

standing structure recording and photographic survey in line with acceptedpractice, and reuse of the slipway cobbles where possible, or use of othersympathetic materials. The desk-based study of the site suggests that noburied heritage assets of very high significance are anticipated that mightmerit a mitigation strategy of permanent preservation in situ. Any adverseeffects could be successfully mitigated by a suitable programme ofarchaeological investigation before and/or during construction, drawing ona range of techniques. This would include subsequent dissemination of theresults and so achieve preservation by record.

9.8.5 Effects on the historic environment such as setting of heritage assetsarising from the operation of the Thames Tunnel will be assessed and

presented in the Environmental Statement. Changes in river flows due tonew infrastructure in the channel could lead to effects on buried heritage


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assets in the foreshore from scouring. Any mitigation requirements foroperational effects will also be presented.

Figure 9.7 Historic environment - Late 19th century sewer outletsunder Putney Bridge

9.9 Land quality

9.9.1 A search of historical and environmental data indicates that the site has noformer uses which are likely to have caused contamination in the area. Nopotential contaminative sources were identified at or in the immediate

vicinity of the site during a walkover survey and previous groundinvestigations close to the site have recorded no significant soilcontamination. Part of the ongoing ground investigations includes theassessment of foreshore sediment contamination. Desk based surveyshave identified a low to medium risk from unexploded ordnance.

9.9.2 There may be a slight adverse effect on construction workers due to thepotential for exposure to contaminated soils or other materials if they arepresent, although any exposure risk would be short-term. There would bea negligible effect on the built environment as it is considered unlikely thatcontaminants contained in subsurface materials would affect buriedstructures. This preliminary assessment therefore identified no need formitigation during the construction phase although this will be clarifiedsubject to further investigations and reported in the EnvironmentalStatement.

9.9.3 During operation there would be negligible effect on future users and thebuilt environment. Based on this preliminary assessment, it is anticipatedthat mitigation would not be required during the operational phase.


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9.10 Noise and vibration

9.10.1 A noise survey has been carried out to understand existing noise levels(Figure 9.8). The site is dominated by road traffic noise. The nearestlocations to the site which are sensitive to noise and vibration are

residential dwellings at Kenilworth Court and Richmond Mansions, locatedto the south of the site; the Star and Garter Mansions and residentialmoorings to the west; and the new Putney Wharf Tower development tothe south east of the site. St. Marys Church has also been identified assensitive to noise.

9.10.2 Based on this preliminary assessment, significant noise and vibrationeffects arising from construction activities are predicted at residentialproperties at Kenilworth Court and Richmond Mansions. No significanteffects as a result of the operation of the site are predicted.

9.10.3 During construction, the contractor would be required to follow best

practice (as described in the Code of Construction Practice) at all times toreduce noise and vibration effects on the local community for examplethrough suitable siting of equipment on site.

9.10.4 Further measures to address significant noise and vibration effects duringconstruction may include localised screens and enclosures to reducenoise from particularly noisy, static operations.

9.10.5 The next stage of the assessment will profile the variation in constructionnoise levels across the programme of work with the aim of refiningmitigation design and seeking to reduce the significant effects ofconstruction noise and vibration. Further details of mitigation measures

will be provided in the Environmental Statement including the significanceof residual effects once mitigation has been taken into account.

Figure 9.8 Recording background noise outside residences alongLower Richmond Road


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9.11 Socio-economics

9.11.1 During construction, there are considered to be moderate adverse effectson the amenity of restaurant and retail business customers and, in turn onthe operators of these businesses (Figure 9.9). Residents couldexperience similar moderate adverse amenity effects. The temporaryrelocation of the slipway and disruption to the river foreshore areconsidered to also have minor adverse effects. The loss of use of a smallarea of open space, disruption to a section of the Thames Path andamenity effects on users of the Thames Path and national cycle route areconsidered to be negligible. Once operational, there would be minorbeneficial effects resulting from the gain in publicly accessible spaceassociated with the Thames Path.

Figure 9.9 Businesses that front the river at Putney Bridge Foreshore

9.11.2 For the operational phase, there are not expected to be any socio-economic effects at Putney Bridge Foreshore which require mitigation.

9.11.3 In completing the assessment, there is scope for further constructionphase mitigation measures to be incorporated in the design with the aim ofseeking to reduce significant adverse amenity effects which have beenidentified in this preliminary assessment.

9.12 Townscape and visual

9.12.1 The site is located within a nationally valued historical and cultural stretchof the River Thames, experienced by large numbers of people and isgenerally in a good condition.

9.12.2 During construction, the use of a temporary retaining wall in the river tocreate a dry working area and hoardings, and the intensity of constructionactivity would have major adverse effects including the site and BishopsPark. There would be moderate adverse effects on the River Thames Fulham and Barn Elms Reach and Putney Bridge Conservation Area dueto the presence of cranes and the intensity of construction activity. Therewould also be minor or negligible effects in the remaining areas included in

the assessment. Once operational there would be minor to moderateadverse townscape effects due to the permanent foreshore structure


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(dependent on the final design) on the site, River Thames Putney andFulham Palace Reach, Bishops Park and Putney Bridge ConservationArea character areas. Two reaches of the River Thames at a distancefrom the site, to the east and the west would have negligible to minoradverse townscape effects due to the introduction of new public realm and

above ground structures in an area previously within the river channel.9.12.3 In terms of visual amenity, during construction there would be major

adverse visual effects on four viewpoints including views from KenilworthCourt, Putney Bridge, the Embankment and Prior Gardens Bank due tothe visibility of the construction site. A view from the Embankment isshown in Figure 9.10. There would be moderate adverse visual effects onviewpoints including Carrara Wharf, Putney High Street and LowerRichmond Road due to visibility of the same elements. Once operational,due to the visibility of the ventilation column, public realm and interceptionchamber, there would be minor to moderate adverse visual effects on

viewpoints including Kenilworth Court, Leaders Gardens and BeverleyBrook. Due to the partially obscured view of above ground structuresthere would be negligible to minor adverse effects on six viewpointsincluding Carrara Wharf, Lower Richmond Road and Leaders Gardens.

9.12.4 Mitigation measures to be employed during the construction phase arebeing incorporated into the proposals, for example, through protection oftrees. In terms of operation, a process of iterative design and assessmentis being employed to reduce adverse effects for example throughlandscape design. Any remaining operational effects will depend on thefinal architectural and landscape design.

Figure 9.10 Panorama view south east from Embankment

9.13 Transport

9.13.1 The Putney Bridge Foreshore site has excellent public transportaccessibility. It is located close to extensive bus services, Putney Pierwhich is served by the Transport for London River Bus and Putney RailStation. The site is located on the Embankment just west of PutneyBridge and construction vehicle access is proposed via the A3 and PutneyBridge Road before routing along Lower Richmond Road and accessingthe site from the Lower Richmond Road/Embankment junction.

9.13.2 During construction, the number of heavy goods vehicle movements wouldbe comparatively low. However, the nature of the construction site layoutat this location would require minor highway layout changes and a minorchange to traffic operation on Embankment, resulting in a moderateadverse effect on road network operation and delay.


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9.13.3 There are a small number of river services that operate from Putney Pierduring peak hours and access to the pier is likely to remain unchangedduring the construction period although a minor adverse effect on servicesmay be expected as a result of the proposed works.

9.13.4 Effects on pedestrian amenity and safety are expected to be moderateadverse and minor adverse for cyclist amenity and safety.

9.13.5 The existing slipway is pictured in Figure 9.11. During the operationalphase there would be very occasional vehicle trips to and from the site formaintenance activities but these would have a negligible effect on thesurrounding transport networks.

9.13.6 The project is being designed to limit the effects on the transport networksas far as possible. At this location, mitigation measures during theconstruction phase are likely to be required and would take the form of asafety audit of the site access and the provision of a traffic marshal tomanage potential conflicts between construction vehicles and pedestrians.It is also proposed to provide a traffic marshal during the operationalphase to manage access when large maintenance vehicles are required toaccess the site through the Lower Richmond Road / Embankmentjunction.

Figure 9.11 Existing slipway at Putney Bridge

9.14 Water resources - ground water

9.14.1 The proposed shaft would pass through the upper aquifer and into theunderlying non aquifer (London Clay). The shaft does not penetrate theprincipal aquifer beneath (Chalk). Associated interception infrastructurewould sit in the upper aquifer founded into the London Clay. The mainreceptor is the upper aquifer and is defined as being of medium value.

9.14.2 Construction and operational effects on the upper aquifer would be limitedto physical obstruction to groundwater flow and this is anticipated to be

negligible due to the inclusion of design measures to reduce groundwatereffects.


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9.14.3 No soil or groundwater contamination has been identified on site to datebut should any be encountered, this would be dealt with using a risk basedapproach and appropriate remediation ahead of construction. The effecton groundwater quality is considered to be negligible at this stage.

9.14.4 Groundwater monitoring of water levels and water quality carried out forthe baseline would continue during construction.

9.15 Water resources surface water

9.15.1 The site is located in the River Thames foreshore within the ThamesUpper waterbody, as classified under the Thames River BasinManagement Plan. There is also the possibility for effects on thedownstream Thames Middle waterbody, which has also been consideredin the assessment. The Thames Upper and Middle waterbodies arecurrently classified under the Water Framework Directive as being atmoderate potential status, with a status objective of good potential by

2027. There are a number of nationally and locally designated water-dependent conservation sites within 2 kilometres of the proposed site.

9.15.2 There is the potential for effects on surface water resources from theproposed construction works through surface water runoff and exposure ofthe drainage system to contaminants. After taking into account themeasures incorporated into the design and Code of Construction Practice,such effects are expected to be manageable and not significant. Nomitigation would therefore be required.

9.15.3 There is also potential for the loss in river bed from the construction tochange the river flows, which could lead to scour at the flood defences.

The effects would be largely temporary during construction as somenatural foreshore restoration would occur after temporary constructionstructures are removed. Some additional mitigation may be required forthe effects of the permanent works within the foreshore. Any mitigationrequired will be identified in the Environmental Statement.

9.15.4 Once operational, the scheme would reduce the number of dischargesfrom the Putney Bridge combined sewer overflow (Figure 9.12) to apredicted level of one spill per year once the tunnel is in place.

9.15.5 This reduction would be a beneficial effect on water quality. The number ofrisk days for river users being exposed to pathogens would be reduced by

up to 104 days of risk of exposure. In addition, the tonnage of sewagederived litter can be expected to be reduced by approximately 17 tonnesto less than half a tonne per year.


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Figure 9.12 Putney Bridge combined seweroverflow outlet

9.16 Flood risk

9.16.1 The site may be at risk of surface water flooding due to runoff generated

from the land to the south. The presence of structures within theforeshore could impact flow within the River Thames and the worksrequired to construct the tunnel could affect the local flood defences;further studies are being completed to assess potential impacts.

9.16.2 Flood defences would be constructed during the construction andoperational phases to provide the equivalent level of flood protection asthat provided by the current flood defences, while maintaining the existingdefences to the south of the Embankment. The finished ground level ofthe site would also be above the design flood level; therefore the risk ofthe operational site flooding from tidal events is negligible.

9.16.3 The effects of changes in scour and deposition would be reduced throughgood practice design of the temporary and permanent structures.

9.17 Further information

9.17.1 Further information regarding preliminary assessment findings for PutneyBridge Foreshore can be found in Volume 10 of the PreliminaryEnvironmental Information Report.


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Section 10: Dormay Street


10 Dormay Street

10.1 Introduction

10.1.1 This section of the non-technical summary presents the preliminary

environmental assessment for the Thames Tunnel project at DormayStreet (Figure 10.1).

10.1.2 At this site it is proposed that the existing Frogmore Storm Relief BellLane Creek combined sewer overflow would be connected to theproposed Frogmore connection tunnel. This tunnel would run north fromthe site to the main Thames Tunnel at Carnwath Road Riverside andsouth to King Georges Park, to connect a further combined seweroverflow into the Thames Tunnel. Currently, the existing combined seweroverflow at Dormay Street discharges approximately 26 times a year atapproximately 17,300m3 each year.

10.1.3 In the following section a description of the existing site is given. This isfollowed by a description of the development proposed at this site.

10.1.4 The environmental topics which have been assessed for this site are listedin the Assessment section (10.4). Preliminary assessment findings arethen presented topic by topic.

10.2 Site context

10.2.1 The site is shown as site number 5 on Figure 28.1.

10.2.2 The site is located within the London Borough of Wandsworth (Figure10.1).

Figure 10.1 Dormay Street site location


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10.2.3 The site, which is made up of hardstanding and industrial buildings, islocated within part of the Frogmore Industrial Complex and CausewayIsland, with the two parts of the site separated by Bell Lane Creek. Thewestern part of the site forms part of a council vehicle storage depot, andthe eastern part of the site is currently occupied by a demolition and civil

engineering contractor. Approximately half a hectare is required for thetemporary construction works as well. This is indicated by the red lineshown on Figure 10.2. The area of land required for the permanent workswould be substantially smaller than that required for construction.

10.2.4 The site is bounded by railway lines and a vehicle storage area to thenorth, the Causeway to the east and a London Borough of Wandsworthmaintenance depot to the west. Access to the site is from Dormay Street.Access to Causeway Island for light vehicles would be via the Causeway.By road, the site is close to Putney Bridge Road, Armoury Way and OldYork Road. There are no Public Rights of Way within the site.

Figure 10.2 Aerial photograph of Dormay Street*

*Note: The red line boundary is approximate in this image


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10.3 Proposed development

10.3.1 The proposal is to intercept the existing combined sewer overflow. Withthe Thames Tunnel in place, instead of untreated sewage discharging atcurrent volumes directly into Bell Lane Creek and then the River Thames,

flows would be diverted into the proposed Thames Tunnel. For a typicalyear, this would reduce flows from this combined sewer overflow to anaverage of 500m3 per year in one overflow event.

10.3.2 In order for this interception to be achieved, construction works at this sitewould take approximately three years.

10.3.3 The construction works would encompass two areas separated by BellLane Creek. The northern area on Causeway Island would be used as atemporary working and storage area, with all permanent structures built inthe southern area. It is likely that a temporary bridge would be built toenable access between the two sites, as the existing crossing is limited in

width and has a weight limit. Construction of the bridge would potentiallyrequire some in-river works. Alternatively a crane might be used. The sitewould be accessed from Dormay Street. To maintain the integrity of theexisting flood defences, located along the southern sites river boundary,river wall strengthening works would be carried out which may also involveworking in the river.

10.3.4 Through an interception chamber, flows from the existing Frogmore StormRelief Bell Lane Creek combined sewer overflow would be diverteddown a shaft with an internal diameter of approximately 12m andapproximate depth of 24m. The shaft would be constructed on the line of

the proposed Frogmore connection tunnel. This tunnel would be 2.6m indiameter, and would run approximately 0.5km south to King GeorgesPark, and 0.6km north to Carnwath Road Riverside, where it would join upwith the main tunnel. The Frogmore connection tunnel would be boredfrom Dormay Street in both directions.

10.3.5 Most of the construction works would take place from 8am to 6pm,Monday to Friday. Limited works may be required beyond these hours,and boring and lining the connection tunnel would require a limited periodof 24 hour working.

10.3.6 In order to manage and mitigate the effects on the environment during

construction, a Code of Construction Practice has been drafted. This setsout measures to be adhered to during the process of construction works.

10.3.7 Figure 10.3 shows an indicative plan of the construction works.


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Figure 10.3 Indicative plan of construction works for Dormay Street

10.3.8 Once the works at this site have been built, a number of permanentfeatures would remain (Figure 10.4). There would be an area ofhardstanding to enable access into the shaft, tunnel and other ancillarystructures for inspection and maintenance purposes. Access for plannedmaintenance purposes would be required every three to six months. Onceevery ten years more substantial maintenance work would be required.

10.3.9 The shaft would be finished to approximately existing ground level, withcovers to allow access and inspection. There would also be covers toenable access to other below ground structures, such as the interceptionchamber.

10.3.10 Above ground structures would include a ventilation structureapproximately 4m high, combined with a kiosk to control equipmentlocated in the below ground chambers, which would be approximately2.5m high. Most of the time the tunnel at Dormay Street is sealed toprevent the release of air. From time to time when the tunnel is filling up,air may be expelled via filters and out through the ventilation column.

10.3.11 Following completion of construction, the council depot would be enlargedto include the Thames Tunnel site to the south of Bell Lane Creek. Thepermanent works would therefore be located inside the enlarged councildepot but Thames Water would retain a right of access for operations and

maintenance purposes.


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Figure 10.4 Dormay Street indicative plan of built development

10.4 Assessment

10.4.1 Based on the existing site and the works proposed, the followingenvironmental topics have been included in the scope of this preliminaryenvironmental assessment:

a. Air quality and odour

b. Ecology aquatic and terrestrial

c. Historic environment

d. Land quality

e. Noise and vibration

f. Socio-economics

g. Townscape and visual

h. Transport

i. Water resources (ground and surface)

j. Flood risk

10.4.2 In the following sections, information about the preliminary assessment ofeach of these topics is presented.


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10.4.3 As part of the assessment process, consideration has been given toknown major developments that may change future environmentalconditions. At this site the main change in land use would arise fromdemolition of buildings on the civil engineering contractors site in 2012 bythe London Borough of Wandsworth (some of which fall within the Thames

Tunnel site) in order to expand the Councils depot into this area. Theassessment assumes that ahead of Thames Tunnel construction theCouncil would temporarily vacate the part of the depot within the ThamesTunnel construction site. It also assumes the Council would resume useof this area for vehicle storage after Thames Tunnel construction iscomplete.

10.4.4 Further information on the topic specific methodology for conducting theassessment is given in section 4 of this non-technical summary.

10.5 Air quality and odour

10.5.1 The Dormay Street site is located within the London Borough ofWandsworth Air Quality Management Area. Local monitoring dataindicates that there are currently exceedences of the air quality standardfor nitrogen dioxide in the vicinity of the site. The nearest people who maybe sensitive to the development are occupiers of nearby residentialdwellings (between Dormay Street and Frogmore and on FrogmoreStreet), and the adjacent commercial and industrial premises.

10.5.2 Based on this preliminary assessment, the overall effect on local air qualityfrom construction road traffic and construction plant is likely to be minoradverse at the residential properties and negligible at the commercial andindustrial premises. In terms of construction dust, this is likely to have aminor adverse effect at the commercial buildings within 10m of the siteand a negligible effect at the residential and industrial premises, takingaccount of the dust control measures in the Code of Construction Practice.

10.5.3 Preliminary assessment findings indicate that the effect of odour from airreleased from the ventilation column, which may occur periodically whenthe tunnel is filling, is likely to be negligible.

10.5.4 Based on this preliminary assessment, it is considered that furthermeasures are not required.

10.6 Ecology aquatic

10.6.1 The sewage outfall that would be intercepted by the development currentlydischarges into Bell Lane Creek, which is part of the designated RiverThames and Tidal Tributaries Site of Metropolitan Importance (Figure10.5). The Creek is a muddy channel, with an intertidal area exposed atlow tide. The channel is underlain by pebbles, silt, cobbles and shingle.The banks are artificial, made of vertical concrete, steel sheet piles andbrick and they support a limited amount of green algae. There are severalsmall areas of marginal reedbed close to the creek mouth. There is nomarginal vegetation in the vicinity of the outfall. The site has some valuefor fish species, and supports only pollution-tolerant invertebrates.


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10.6.2 Construction effects would be managed in accordance with a Code ofConstruction Practice. With the Code in place and based on assessmentfindings at this stage, landtake, disturbance and compaction of habitatsfrom construction of the temporary bridge, would result in minor adverseeffects. Pollution of habitats due to spillages would be negligible. Effects

on fish would be minor adverse. Effects on invertebrates and mammalswould be negligible.

10.6.3 It is anticipated that during operation, the reduction in fish mortality thatwould result from improved oxygenation of the water is considered amoderate beneficial effect. In the longer term of operation there would bea moderate beneficial effect through increased distribution of rare and/orpollution sensitive fish species. Effects on invertebrates would be minorbeneficial and negligible on mammals.

10.6.4 Construction effects would be managed in accordance with the Code ofConstruction Practice. No further mitigation during construction is

considered possible at this site at this stage. No mitigation is requiredduring operation because no adverse effects are anticipated.

Figure 10.5 The aquatic ecology survey site on Bell Lane Creek, looking southtowards the site.


10.7.1 Bell Lane Creek, which is part of the designated River Thames and Tidal

Tributaries Site of Metropolitan Importance, runs through the site. The sitemainly comprises buildings, hardstanding and foreshore habitat, smallareas of short perennial vegetation, scattered trees and dense scrub.There is a small area of potential reptile habitat. The site is likely to be ofvalue to bats, breeding birds, black redstart, wintering birds andinvertebrates. It is also likely to have some botanical interest. Surveys forthese species are ongoing and the results will be reported in theEnvironmental Statement. Japanese knotweed, an invasive plant, is alsopresent on site and this will be removed prior to construction whererequired. There are three designated sites within 500m of the site.


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10.7.2 Based on preliminary assessment findings, during construction no adverseeffects are anticipated on designated sites due to their distance from thesite and the relatively localised nature of the proposed works (aquaticecology effects are considered in section 10.6). Site clearance wouldresult in the loss of several mature trees and shrubs which would be an

adverse effect of local significance. Habitat loss and disturbance effectson notable species will be assessed and reported in the EnvironmentalStatement. Effects on reptiles are likely to be negligible. Effects on bats,black redstart, breeding birds, wintering birds, invertebrates and anyspecies of botanical interest will be assessed and reported in theEnvironmental Statement.

10.7.3 Operational activity would be limited to occasional maintenance works,which are unlikely to have significant effects on terrestrial ecology.

10.7.4 In addition to measures in the Code of Construction Practice, measures toaddress adverse effects during construction are likely to include

reinstatement and replacement of trees and planting. Further measures,such as disturbance minimisation, will be formulated subject to surveyresults if required.


10.8.1 The site contains no nationally designated heritage assets. The grade IIlisted early 18th-century Wentworth House lies approximately 40m to thesouth of the site. There is little above ground heritage interest within thesite, although a 19th century barge bed and boundary wall are present.

10.8.2 The site lies within a locally designated Archaeological Priority Area and

the main potential in terms of buried heritage is for palaeoenvironmentalremains e.g. organic remains such as pollens or plant fossils within theWandle floodplain alluvium, which would be of low or medium heritageasset significance. There is also potential for evidence of prehistoricactivity (of low to high heritage asset significance depending on the natureand condition of any finds), and post-medieval 18th19th century footingsof industrial buildings (of low heritage asset significance). There is also amoderate potential for later medieval waterfront features of low or mediumheritage asset significance.

10.8.3 Piling for the temporary bridge could remove parts of the 19th centurybarge bed, constituting a moderate adverse effect. Construction workswould entail deep excavations which would entirely remove any buriedassets within the excavation footprint if any such assets were present. Ifsuch assets were present, this would comprise a high magnitude of impactand would give rise to a minor adverse effect on palaeoenvironmentalremains and post-medieval remains, a minor to major adverse effect onprehistoric remains, and a minor or moderate adverse effect on latermedieval remains.

10.8.4 Effects on the barge bed could be mitigated by moving the bridge awayfrom the structure. However, if this is not possible, archaeologicalexcavation and recording to form preservation by record would be

undertaken. The desk-based study of the site suggests that no buriedheritage assets of very high significance are anticipated that might merit a


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mitigation strategy of permanent preservation in situ. The adverse effectscould be successfully mitigated by a suitable programme of archaeologicalinvestigation before and/or during construction, drawing on a range oftechniques. This would include subsequent dissemination of the resultsand so achieve preservation by record.

10.8.5 Effects on the setting of heritage assets in the surrounding area arisingfrom the presence of visible above ground operational structures, will beassessed and presented in the Environmental Statement. Any mitigationrequirements for operational effects will also be presented.

10.9 Land quality

10.9.1 Historical and environmental data indicates that there is potential forhistorical contamination sources at the site. The site has been used as adepot and for electricity works. Causeway Island may have below groundmaterial linked with the filling in of part of Bell Lane Creek. Historical data

also shows that the local area was heavily industrialised from the late 19thcentury onwards, with surrounding uses including a sizable gas works, tarworks and wharves. However, previous ground investigations haverecorded no significant contamination of the soils on site. Although somecontamination of groundwater in the northern part of the site has beenidentified. Desk based surveys have identified a low to medium risk fromunexploded ordnance.

10.9.2 Based on preliminary assessment findings, there could be a slight adverseeffect on construction workers due to the potential for exposure tocontaminated soils or other materials, although any exposure risk wouldbe short-term limited to the construction period. There would be anegligible effect on the built environment as it is considered unlikely thatcontaminants contained in subsurface materials would affect buriedstructures.

10.9.3 During operation there would be a negligible effect on future users of thesite and on built structures within the site.

10.9.4 Based on preliminary assessment findings to date, it is unlikely thatmitigation during the construction or operational phases would berequired.


10.10.1 The site is subject to road traffic and rail noise (Figure 10.6). The nearestlocations to the site which are sensitive to noise and vibration areresidential dwellings to the south of the site along the A3 and ArmouryWay and between Dormay Street and Frogmore.

10.10.2 Information relating to the project wide assessment of predictedgroundborne noise and vibration impacts arising from the operation oftunnel boring machine and the temporary construction railway serving thetunnel boring machine during construction of the Frogmore ConnectionTunnel is contained in section 5.5.


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10.10.3 Based on this preliminary assessment, no significant effects from vibrationduring construction are predicted. Significant noise effects arising fromconstruction activities are predicted at residential properties on ArmouryWay and London Court.

10.10.4 During construction, the contractor would be required to follow bestpractice (as described in the Code of Construction Practice) at all times toreduce noise and vibration effects on the local community for examplethrough suitable siting of equipment on site.

10.10.5 Further measures to address significant noise and vibration effects duringconstruction may include localised screens and enclosures to reducenoise from particularly noisy, static operations.

10.10.6 The next stage of the assessment will profile the variation in constructionnoise levels across the programme of work with the aim of refiningmitigation design and seeking to reduce the significant effects ofconstruction noise and vibration. Further details of mitigation measureswill be provided in the Environmental Statement including the significanceof residual effects once mitigation has been taken into account.

10.10.7 No significant effects from noise or vibration during the operation of thesite are predicted.

Figure 10.6 Railway line located to the north of the site.


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10.11.1 The site is currently occupied by a civil engineering contractor, whichwould vacate the site in early 2012, and a Council depot. The WandleTrail and a national cycle route pass adjacent to the site along a private

road. These are moderately well used for walking and cycling. Industrialand storage uses immediately surround the site.

10.11.2 During construction, there would be minor adverse effects arising from theloss of employment land. There would also be minor effects on amenityon users of the Wandle Trail and the national cycle route. The temporaryreduction in the area of the Council depot would have a negligible effect.

10.11.3 Once operational, there would be a negligible effect on the availability ofemployment land resulting from the presence of operational structures onthe site.



10.12.1 The site comprises two industrial buildings, a storage shelter and river wallwhich are generally in poor condition. The surrounding townscape is a mixof industrial, commercial and residential properties.

10.12.2 Based on preliminary assessment findings, the demolition of buildings,presence of cranes, construction traffic and intensity of constructionactivity would have moderate adverse effects on the character of the siteand the Dormay Street industrial character area. There would be minoradverse effects on Wandsworth Town Conservation Area and FrogmoreResidential Area. Once operational, preliminary assessment findingsindicate there would be a minor beneficial townscape effect on the site andDormay Street Industrial Area due to the removal of existing buildings,provision of new hardstanding areas and the provision of a well-designedventilation structure.

10.12.3 In terms of visual amenity preliminary assessment findings indicate thatduring construction, due to the visibility of cranes and site hoardings, there

would be moderate adverse effects on viewpoints on The Causeway, BellLane Creek and Dormay Street. There would be minor adverse effects onviewpoints on Fairfield Street and Armoury Way due to the visibility ofcranes. Once operational, there would be moderate beneficial visualeffects on the viewpoint at Bell Lane Creek and minor beneficial effects onthe viewpoints at the Causeway and Dormay Street due to the removal ofexisting buildings and the provision of a well-designed ventilationstructure.

10.12.4 Mitigation measures during the construction phase are being incorporatedinto the proposals, for example, through use of capped and directional

lighting when required. There would be no significant adverse effectsduring operation and therefore no further mitigation is proposed.


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10.13 Transport

10.13.1 The site has very good public transport accessibility, being located in closeproximity to a number of high frequency bus stops and within 800m ofWandsworth Town Rail Station and the Wandsworth Riverside Quarterpier.

10.13.2 Construction vehicle access is proposed via the A3 and Upper RichmondRoad (A205), Armoury Way and then Dormay Street. During construction,the number of heavy goods vehicle movements would be moderate to high(at peak times). The presence of construction activity would result in aminor to moderate adverse effect on road network operation and delayand a moderate effect on pedestrian and cyclist amenity. A negligibleeffect is expected on public transport and river passenger services.

10.13.3 During the operational phase there would be very occasional vehicle tripsto and from the site for maintenance activities, which would have a

negligible effect on the surrounding transport networks.10.13.4 The project is being designed to limit effects on the transport networks as

far as possible. At this location, mitigation measures during constructionwould involve the provision of safe crossing points for pedestrians andcyclists where needed. Mitigation is not required for the operationalphase.

10.14 Water resources groundwater

10.14.1 The shaft would pass through the upper aquifer, which is of medium value,and into the underlying London Clay (which is not an aquifer). The shaftwould not penetrate the lower chalk aquifer beneath. Associatedinterception infrastructure would be located in the upper aquifer.

10.14.2 Construction and operational effects on the upper aquifer would be limitedto physical obstruction to groundwater flows. This effect is anticipated tobe negligible due to the inclusion of design measures to reducegroundwater effects.

10.14.3 No soil or groundwater contamination has been identified on site to datebut should any be encountered, the risks would be assessed andappropriate remediation undertaken. The effect on groundwater quality isconsidered to be negligible.

10.14.4 Groundwater monitoring of water levels and water quality would beundertaken during construction and operation.


10.15.1 The site spans Bell Lane Creek, which forms the tidal section of the RiverWandle. It joins the River Thames approximately 250m north of the site.

10.15.2 The River Thames in the vicinity of the site is classed as being ofmoderate status, with a status objective of good by 2027. The RiverWandle (including the Bell Lane Creek) is classed as being of poorstatus, with a status objective of good by 2027. There are a number of

nationally and locally designated water-dependent conservation siteswithin 2km of the site.


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10.15.3 Construction effects would be managed via the Code of ConstructionPractice. With the Code in place effects on surface water resources fromsurface water runoff and potential contamination of the drainage systemare not expected to be significant.

10.15.4 The presence of the temporary bridge in the river channel could lead tochanges in flows and hence scour of flood defences. This effect would belimited to the construction phase, as following removal of the bridgestructure river flows would return to normal and some natural foreshorerestoration would occur. Any mitigation that is required will be identified inthe Environmental Statement.

10.15.5 No mitigation would be required during construction in terms of waterquality. Measures may be required to address scour of flood defences. Ifrequired, these will be assessed and reported in the EnvironmentalStatement.

10.15.6 Once operational, the scheme would reduce the number of dischargesfrom the Frogmore Storm Relief Bell Lane combined sewer overflow to apredicted level of one spill a year. This reduction would have a beneficialeffect on water quality. The number of risk days for river users beingexposed to pathogens would be reduced by up to 104 days per year. Inaddition, the tonnage of sewage derived litter could be expected to bereduced from 4 tonnes to less than a tenth of a tonne per year.

10.16 Flood risk

10.16.1 The southern section of the site is located on the banks of Bell LaneCreek, a tidal inlet of the River Thames, and is within the high probability

flood zone. However, it is protected from tidal flooding by the ThamesBarrier and local flood defences (Figure 10.7). The northern section of thesite, on Causeway Island, is also located within the high probability floodzone but no formal flood defences are present here.

10.16.2 The site may also be at risk of localised surface water flooding due torunoff generated by impermeable surfaces in and around the site.Excavations required to construct the Frogmore connection tunnelbeneath the site have the potential to cause settlement, which could affectthe flood defences along the edge of Bell Lane Creek. Further studies areunderway to assess these potential effects.

10.16.3 The current level of protection afforded by the defences would bemaintained on the site during construction and operation. It may benecessary to stabilise and strengthen existing defences in some places;this will be confirmed following further defence condition surveys.


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Figure 10.7 Current river walls present on the banks of Bell LaneCreek

10.17 Further information

10.17.1 Further information regarding preliminary assessment findings for DormayStreet can be found in Volume 11 of the Preliminary EnvironmentalInformation Report.


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Section 11: King Georges Park


11 King Georges Park

11.1 Introduction

11.1.1 This section of the non-technical summary presents the preliminary

environmental assessment for the Thames Tunnel project at KingGeorges Park.

11.1.2 At this site it is proposed that the existing Frogmore Storm ReliefBuckhold Road Sewer would be linked to the proposed Thames Tunnelvia a shaft and a connection tunnel (the proposed Frogmore connectiontunnel). Currently the existing combined sewer overflow dischargesapproximately 19 times a year. The total volume of this discharge is85,600m3 each year.


11.1.4 The environmental topics which have been assessed for this site are listedin the Assessment section (11.4). Preliminary assessment findings arethen presented topic by topic.

11.2 Site context

11.2.1 The site is shown as site number 6 on Figure 28.1.

11.2.2 The site is located within the London Borough of Wandsworth (Figure11.1).

Figure 11.1 King Georges Park site location


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11.2.3 The site is located at the northern end of King Georges Park, adjacent tothe park entrance from Buckhold Road. Approximately 0.2ha is requiredfor the temporary construction works. This is indicated by the red lineshown on Figure 11.2. The area of land required for the permanent workswould be substantially smaller than that required for construction.

11.2.4 The site is bounded by residential and commercial properties to the north,east and west, and by the main area of the park to the south. The site isaccessible from various pedestrian park entrances, but there is currentlyno public vehicular access to the park. The park is crossed by a numberof footpaths, although there are no statutory public rights of way.

Figure 11.2 Aerial photograph of King Georges Park*



11.3.1 The proposal is to intercept the existing combined sewer overflow. Withthe Thames Tunnel in place, instead of untreated sewage discharging at

current volumes directly into the River Wandle and then the River Thames,flows would be diverted into the proposed Thames Tunnel. For a typicalyear, this would reduce flows from the combined sewer overflow to anaverage of approximately 1,500m3 /year.

11.3.2 In order for this interception to be achieved, construction works at this sitewould take approximately two and a half years. A temporary constructionaccess would be created off Neville Gill Close, this would require loweringof the existing curb and removal of the iron railing fence.

11.3.3 Trees located within the footprint of the site would be removed and thosebordering the site would be pruned back, and the topsoil would be stored

for reinstatement when works are complete. During construction, treesadjacent to the site would be protected.


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11.3.4 Through an interception chamber, flows from the existing Frogmore StormRelief Buckhold Road combined sewer overflow would be diverted downa shaft with an internal diameter of approximately 9m and approximately20m deep. The shaft would be constructed on the line of the proposedFrogmore Connection Tunnel, which would run approximately 1.1km from

King Georges Park to Carnwath Road, via Dormay Street, and would be2.6 metres in diameter. At Carnwath Road it would join up with the maintunnel.

11.3.5 Most of the construction works would take place from 8am to 6pm,Monday to Friday. Limited works may be required beyond these hours.

11.3.6 In order to manage and mitigation the effects on the environment duringconstruction, a Code of Construction Practice has been drafted. This setsout measures to be adhered to during the process of constructionworks.Figure 11.3 shows an indicative plan of the construction works.

Figure 11.3 Indicative plan of construction works for King Georges Park

11.3.7 Once the works at this site have been built, a number of permanent workswould remain (Figure 11.4). There would be an area of hardstandingaround the infrastructure to enable access into the shaft, tunnel and otherancillary structures for inspection and maintenance purposes. This wouldusually be publicly accessible except during maintenance when it wouldbe fenced off. Access for planned maintenance would be required everythree to six months. Once every ten years more substantial maintenance

work would be required.


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11.3.8 There would be a new gated access for maintenance vehicles of NevilleGill Close.

11.3.9 The shaft would be finished level with the surrounding hardstanding whichwould be approximately 1 metre above existing ground level, because theexisting sewer is shallow at this location so requires infrastructure to beraised above it. This level would also ensure the infrastructure isprotected from the risk of flooding and enables direct vehicle access fromNeville Gill Close which is elevated above the park level. There would becovers on top of the shaft to allow access and inspection. The other belowground structures would also have covers to enable access andinspection.

11.3.10 Above ground structures would include a ventilation column approximately6m high to let air out of the interception chamber during times of flows.There would also be a separate ventilation column approximately fourmetres high linked to the shaft. Most of the time, air would be drawn into

the shaft and tunnel via the 4 metre ventilation column and throughlouvres (housed in a separate above ground ventilation structureapproximately 2.5 metres high), to ensure that the air within the maintunnel is continuously circulated. From time to time when the tunnel isfilling up, air may be expelled via below ground filters and out through theventilation system. There would also be a separate kiosk, approximately2.5 metres high, to house electrical and control equipment.

Figure 11.4 King Georges Park indicative plan of built development


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11.4 Assessment


a. Air quality and odourb. Ecology aquatic and terrestrial


d. Land quality


f. Socio-economics


h. Transport

i. Water resources (ground and surface)

j. Flood risk


11.4.3 As part of the assessment process, consideration has been given toknown major developments that may change future environmentalconditions. At King Georges Park consideration has been given to theBusiness Village, a mixed use development in Broomhill Road and theCockpen House development of several buildings with residential and

commercial space.



11.5.1 The King Georges Park site is located within the London Borough ofWandsworth Air Quality Management Area. Local monitoring dataindicates that there are currently exceedences of air quality standards inthe vicinity of the site. The nearest people who may be sensitive to thedevelopment are occupiers of nearby residential dwellings (on Buckhold

Road) and commercial and office premises including Southside shoppingcentre and the new Business Village, as well as users of a nearby daycentre, nursery, clinic, West Hill Centre (adult college) and Army CadetForce building, and visitors to the childrens zoo in the park.

11.5.2 Based on this preliminary assessment, it is considered that the overalleffect on local air quality from construction road traffic and constructionplant is likely to be minor adverse at the residential properties, day centre,nursery, clinic, adult college and Army Cadet Force building and negligibleat the commercial/office premises and park/zoo. In terms of constructiondust, this is likely to have a minor adverse effect on the Army Cadet Force

building, clinic, nursery and day centre and a negligible effect elsewhere,


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taking account of the dust control measures in the Code of ConstructionPractice.

11.5.3 Preliminary assessment findings indicate that the effect of odour from airreleased from the ventilation column, which may happen from time to timewhen the tunnel is filling, is likely to be negligible.

11.5.4 Based on this assessment, it is considered that mitigation measures arenot required.

11.6 Ecology aquatic

11.6.1 The sewage outfall that would be intercepted currently discharges into asection of the River Wandle which is covered beneath the Southsideshopping centre. The non-tidal River Wandle is designated as a Site ofBorough Importance. The downstream Wandle is part of the River Thamesand Tidal Tributaries Site of Metropolitan Importance.

11.6.2 There would be no in-river works associated with this site. No furtherconsideration of the impacts associated with construction has thereforebeen undertaken for aquatic ecology. Effects on the ornamental lake areconsidered in the terrestrial ecology assessment.

11.6.3 During operation, reduction in nutrient levels entering the river would havea moderate beneficial effect on habitats. The reduction in fish mortalitythat would result from improved oxygenation of the water is alsoconsidered a moderate beneficial effect. There would also be a moderatebeneficial effect through increased distribution of rare and/or pollutionsensitive fish species. All effects on invertebrates would be minorbeneficial by year six. Effects on mammals would be negligible.

11.6.4 No mitigation is required at this site because no adverse effects areanticipated.


11.7.1 The site is within King Georges Park Site of Importance for NatureConservation. The site comprises hardstanding, amenity grassland,scattered trees and introduced shrub. These habitats continue into thewider park and include a large ornamental lake. The site is of value tocommon nesting birds, common amphibians, hedgehogs andinvertebrates. It is also of potential value to roosting and foraging bats.

Surveys for the latter species are ongoing and will be reported in theEnvironmental Statement.

11.7.2 Based on preliminary assessment findings, the majority of effects onterrestrial ecology would be of site level adverse significance. The loss oftrees would have a local adverse effect. Disturbance to breeding birds islikely to be negligible. The effects on bats will be assessed and reported inthe Environmental Statement.

11.7.3 It is anticipated that operational activity would be limited to occasionalmaintenance works, which are considered unlikely to have significanteffects on terrestrial ecology.


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11.7.4 In addition to measures in the Code of Construction Practice, whichincludes protection of trees, measures to address adverse effects duringconstruction may include reinstatement and replacement of trees andplanting. Further measures for bats will be developed subject to surveyresults as required and will be assessed and reported in the

Environmental Statement.


11.8.1 The site is located within King Georges Park, which was established inthe 1920s, and is of medium heritage asset significance. The site containsno nationally designated heritage assets. Down Lodge, a Grade II listedbuilding, constructed in the mid to late 18th century, lies around 160m tothe southwest.

11.8.2 The site lies within an Archaeological Priority Area and the main potentialin terms of buried heritage is for palaeoenvironmental remains (eg organic

remains such as pollens or plant fossils) of low or medium heritage assetsignificance, and post-medieval drainage ditches of low or negligibleheritage asset significance. The potential for earlier (prehistoric, Romanand medieval) remains is considered to be low, as the site lay outside theknown areas of settlement in these periods (Figure 11.5).

11.8.3 Construction works would entail removal of the railings at the northern endof the park which would give rise to a minor adverse effect. Deepexcavations would entirely remove any buried heritage assets within thefootprint of each excavation. If any buried assets were present, this wouldcomprise a high magnitude of impact and lead to a minor or moderateadverse effect on palaeoenvironmental remains, and a minor adverseeffect on post-medieval ditch remains.

11.8.4 To mitigate the effect on the park railings, a basic visual record of therailings and park would be made prior to the start of construction. Thedesk-based study of the site suggests that no buried heritage assets ofvery high significance are anticipated that might merit a mitigation strategyof permanent preservation in situ. The adverse effects could besuccessfully mitigated by a suitable programme of archaeologicalinvestigation before and/or during construction, drawing on a range oftechniques. This would include subsequent dissemination of the resultsand so achieve preservation by record.

11.8.5 Effects from the operation of the Thames Tunnel infrastructure on thehistoric setting of heritage assets in the surrounding area will be assessedand presented in the Environmental Statement. Any mitigationrequirements will also be presented.


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Figure 11.5 Rocques map of 1746

11.9 Land quality

11.9.1 A search of historical and environmental data indicates that the site hasnot been subject to significant previous contaminative uses. Historicalmapping indicates that the site has remained undeveloped since the late

19th century. No potential contaminative sources were identified at or inthe immediate vicinity of the site during a walkover survey. Although someminor commercial and light industrial buildings are located on the oppositeside of Buckhold Road. Previous ground investigations have recorded nosignificant soil contamination. Low levels of groundwater contaminationlevels have been recorded. Desk based surveys have identified a mediumto high risk from unexploded ordnance.

11.9.2 Based on preliminary assessment findings, there could be a slight adverseeffect on construction workers due to the potential for exposure tocontaminated soils or other materials, although any exposure risk wouldbe short-term limited to the construction period. There would be anegligible effect built structures, such as existing sewerage infrastructureat the site, as it is considered unlikely that contaminants contained insubsurface materials would affect buried structures.

11.9.3 During operation there would be a negligible effect on future users and thebuilt environment.

11.9.4 Based on the information reviewed to date no mitigation is anticipatedduring construction or operation.


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11.10.1 A noise survey has been carried out around the site (Figure 11.6). Thesite is dominated by road traffic noise. The nearest locations to the sitewhich are sensitive to noise and vibration are residential dwellings at

Albon House.11.10.2 Based on this preliminary assessment, significant noise effects arising

from construction activities are not predicted. Significant vibration effectsarising from construction are however predicted at residential properties atParkview Court. No significant effects as a result of the operation of thesite are predicted.

11.10.3 During construction activities, the contractor would be required to followbest practice (as described in the Code of Construction Practice) at alltimes to reduce noise and vibration effects upon the local community forexample through suitable siting of equipment on site.

11.10.4 In order to address the significant effect from vibration, further measuresmay be required which could include careful selection of equipment andprogramming of particular activities to minimise potential disturbance.

11.10.5 The next stage of the assessment will profile the variation in constructionnoise levels across the programme of work with the aim of refiningmitigation design and seeking to reduce the significant effects ofconstruction noise and vibration. Further details of mitigation measureswill be provided in the Environmental Statement including the significanceof residual effects once mitigation has been taken into account.

Figure 11.6 Recording background noise along Buckhold Road,

outside King Georges Park


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11.11.1 The site comprises an area of green open space, forming part of a largerpark. Within the park to the south of the site are a Childrens Centre andplayground, and ornamental lake. Residential dwellings and other uses,

including the Penfold Day Centre, Southside shopping centre andbusiness units surround the rest of the site (Figure 11.7). The open spaceis moderately well used for informal recreation.

Figure 11.7 Penfold Centre

11.11.2 During construction, there would be moderate adverse effects on the

amenity of users of the Childrens Centre and the amenity of users of KingGeorges Park open space. There would be minor adverse effects on theamenity of nearby residents and on users of King Georges Park openspace as a result of temporary loss of use of an area of open space. Theamenity impacts on users of the Penfold Day Centre would be negligible.Once operational, there would be a negligible effect resulting from the lossof open space associated with the permanent operational structures.


11.11.4 For the operational phase no socio-economic effects requiring mitigationare predicted at this stage of the assessment.


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11.12.1 The site is located in the northern tip of King Georges Park, adjacent toBuckhold Road and Neville Gill Close. It comprises open grassland andmature trees. The condition of the townscape is generally good.

11.12.2 Based on preliminary assessment findings, during construction theclearance of vegetation, presence of site hoardings and intensity ofconstruction activity would have major adverse effects on the character ofthe site and the King Georges Park character area. There would bemoderate adverse effects on King Georges Sports Ground andWandsworth Town Residential Area due to vegetation clearance and thepresence of cranes, site hoardings and the intensity of constructionactivity. Once operational, preliminary assessment findings indicate thatthere would be minor to moderate beneficial townscape effects on the siteand King Georges Park due to the creation of a new high quality publicrealm. The level of significance is dependent on the design and will be

refined for the Environmental Statement.

Figure 11.8 View north from the lakeside footpath close to the tenniscourts

11.12.3 In terms of visual amenity, during construction there would be majoradverse visual effects on five viewpoints, including Buckhold Road, andviews from within King Georges Park. There would be moderate adverseeffects on views from Fosters Walk, Wandsworth High Street and NevilleGill Close due to the visibility of tree clearance, cranes and constructionactivity. There would be minor adverse visual effects on six viewpointsincluding viewpoints on Buckhold Road, Merton Road and Broomhill Roaddue to the visibility of tree clearance and cranes. Once operational, therewould be minor to moderate beneficial visual effects on three viewpointsincluding the Chinese bridge, lakeside footpath close to the tennis courts


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and lakeside footpath close to the play area due to the creation of a newhigh quality public realm. There would be negligible to minor beneficialeffects on views from Neville Gill Close due to visibility of the new highquality public realm and minor adverse visual effects on the viewpoint onBuckhold Road due to the loss of trees within the park. The level of

significance is dependent on the design and will be refined for theEnvironmental Statement.

11.12.4 Mitigation measures during the construction phase are being incorporatedinto the proposals, for example, protection of trees. In terms of operation,a process of iterative design and assessment is being employed to reduceadverse effects which will continue until the scheme design is finalised.This will be reported in the Environmental Statement.

11.13 Transport

11.13.1 The King Georges Park site has good public transport accessibility being

located within close proximity of bus stops serving Putney, ClaphamJunction, Vauxhall and Wimbledon. The site is on the west side of NevilleGill Close and construction vehicle access is proposed via WandsworthHigh Street (A3), Buckhold Road (A218) and Neville Gill Close.

11.13.2 During construction, the number of heavy goods vehicle movements wouldbe comparatively low. Construction traffic and the site layout areconsidered likely to result in a minor adverse effect on road networkoperation and delay. Effects on pedestrian and cyclist amenity and safetyare expected to be minor adverse and negligible, respectively. Anegligible effect is expected on public transport and river passengerservices. During the operational phase there would be very occasionalvehicle trips to and from the site for maintenance activities and thesewould have a negligible effect on the surrounding transport networks.

11.13.3 The project is being designed to limit the effects on transport networks asfar as possible. At this location, mitigation measures during theconstruction phase are likely to include provision of safe crossing pointsfor pedestrians across the site access. Mitigation is not required for theoperational phase.

11.14 Water resources - ground water

11.14.1 The proposed shaft would pass through the upper aquifer, which is of

medium value, and into the underlying London Clay (which is not anaquifer). The shaft does not penetrate the lower chalk aquifer beneath.Associated interception infrastructure would be located in the upperaquifer.

11.14.2 Construction and operational effects on the upper aquifer would be limitedto physical obstruction to groundwater flow and this is anticipated to benegligible.

11.14.3 No soil or groundwater contamination has been identified on site to datebut should any be encountered, the risks would be assessed andappropriate remediation undertaken. The effect on groundwater quality ispredicted to be negligible.


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11.14.4 Monitoring of groundwater levels and quality would be undertaken duringconstruction.


11.15.1 The site is located 200 metres to the east of the River Wandle and one

kilometre south of the River Thames. In addition to these twowatercourses, there is a lake located within King Georges Park; this isassumed to be an artificial lake, which is manually filled and not linked tothe Wandle or its tributaries (Figure 11.9).

11.15.2 The section of the River Thames closest to the site, and a stretchdownstream which could also be affected, are classified as being ofmoderate quality status, with a status objective of good by 2027. TheRiver Wandle is classed as being of poor status, with an overall statusobjective of good by 2027. There are a number of nationally and locallydesignated water-dependent conservation sites within 2 kilometres of the

site.11.15.3 Construction effects would be managed via the Code of Construction

Practice. With the Code in place effects on surface water resources fromsurface water runoff and potential contamination of the drainage systemare not expected to be significant. No mitigation would therefore berequired.

11.15.4 Once operational, the scheme would reduce the number of dischargesfrom the Frogmore Storm Relief Buckhold Road combined seweroverflow to a predicted level of one spill per year. This reduction wouldhave a beneficial effect on water quality. The number of risk days for river

users being exposed to pathogens would be reduced by up to 80 days peryear. In addition, the tonnage of sewage derived litter could be expected tobe reduced from approximately 22 tonnes to less than one tonne per year.

Figure 11.9 View of lake in King Georges Park


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11.16 Flood risk

11.16.1 The main source of flood risk to the site is from the tidal River Thames andthe River Wandle. The site is located within the high probability floodzone, although it is protected from tidal flooding by defences which runalong the banks of the Thames.

11.16.2 During extreme fluvial flood events, the River Wandle could burst its banksand flood the park area. The development could therefore potentiallyreduce the volume of flood storage within the Park. As far as possible thedesign is being configured to ensure there would be no increase in floodrisk throughout the surrounding area due to the development. Furtherstudies are underway to assess potential effects on flooding.

11.16.3 The hard standing areas surrounding the shaft could potentially increasesurface water runoff from the site, and appropriate mitigation measureswill be developed to manage surface water in line with current policy

requirements.11.17 Further information

11.17.1 Further information regarding preliminary assessment findings for KingGeorges Park can be found in Volume 12 of the PreliminaryEnvironmental Information Report.


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Section 12: Carnwath Road Riverside


12 Carnwath Road Riverside

12.1 Introduction

12.1.1 This section of the non-technical summary presents the preliminaryenvironmental assessment for the Thames Tunnel project at the CarnwathRoad Riverside site (Figure 12.1).

12.1.2 The site at Carnwath Road Riverside has a number of key functions forthe Thames Tunnel. Firstly, it would be used to drive the tunnel boringmachine westwards to build the main tunnel which terminates at ActonStorm Tanks. Secondly, the tunnel boring machine which would be drivenwestwards from Kirtling Street would then be removed at the CarnwathRoad Riverside site. Thirdly, the tunnel boring machine used to constructthe connection tunnel from Dormay Street would also be received at theCarnwath Road Riverside site. Fourthly, throughout the length of theproposed Thames Tunnel there would be a secondary lining. The

secondary lining between Carnwath Road Riverside and Acton StormTanks would be carried out simultaneously from both ends of this stretchof main tunnel. Finally, this site would include ventilation facilities. It isnoted that there is no combined sewer overflow at this site.


12.1.4 The environmental topics which have been assessed for this site are listedin the Assessment section (0). Preliminary assessment findings are thenpresented topic by topic.

12.2 Site context12.2.1 The site position along the route of the Thames Tunnel is shown as site

number 7 on Figure 28.1.

12.2.2 The Carnwath Road Riverside site is located within the London Borough ofHammersmith and Fulham (Figure 12.1).


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Figure 12.1 Carnwath Road Riverside site location

12.2.3 The site includes Hurlingham Wharf, a safe-guarded wharf which is

currently vacant and has not been used as an operational wharf forthirteen years, as well as Whiffin Wharf to the west. Carnwath RoadIndustrial Estate is to the east and contains a number of two storeyindustrial, warehouse and retail units. During construction the site wouldextend into the River Thames forming the southern boundary of the site.Existing access is via Carnwath Road. The construction area extendsover approximately 3.5 hectares as indicated by the red line shown onFigure 12.2. The area of land required for the permanent works would besubstantially smaller than that required for construction.


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Figure 12.2 Aerial photograph of Carnwath Road Riverside*



12.3.1 A shaft measuring approximately 25 metres in diameter with a depth of

approximately 42 metres is proposed. The shaft has been sized tofacilitate access for launching and removing the tunnel boring machines aswell as providing access into the shaft and tunnel for maintenancepurposes.

12.3.2 The proposed development would include the construction of a 6.5 metreinternal diameter main tunnel from Carnwath Road Riverside to ActonStorm Tanks (site number 1 on Figure 28.1). This would be a continuous24 hour construction operation, with almost all of the excavated materialfrom the tunnelling transported away by barge.

12.3.3 The tunnel boring machine used to excavate the main tunnel driven

westwards from Kirtling Street (site number 11 on Figure 28.1) would beremoved at Carnwath Road Riverside. A further tunnel boring machineused to excavate a connection tunnel which would be driven northwardsfrom Dormay Street would also be removed at the Carnwath RoadRiverside site. There would be flows into this connection tunnel from thecombined sewer overflows at Dormay Street (site number 5 on Figure28.1) and King Georges Park (site number 6 on Figure 28.1) with theseflows then transferred into the main tunnel.


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12.3.4 It is assumed that there would be secondary lining proposed along thelength of the main tunnel. Carnwath Road is one of the sites from wheresecondary lining would be carried out. The purpose of secondary lining ofthe main tunnel is to increase durability, to enhance structural integrity, toreduce the possibility of leaks out of the tunnel and to also avoid leaks into

the tunnel from groundwater.12.3.5 Access into the site during construction would be from Carnwath Road as

well as from the river front for barging.

12.3.6 In order to manage and mitigation the effects on the environment duringconstruction, a Code of Construction Practice has been drafted. This setsout measures to be adhered to during construction.

12.3.7 Figure 12.3 shows an indicative plan of the construction works.

Figure 12.3 Indicative plan of construction works for Carnwath Road Riverside

12.3.8 Once the works at the site have been built, a number of permanentfeatures would remain (Figure 12.4). The shaft would be finished to matchthe existing ground level with covers on the shaft top. There would be anarea around the shaft covers provided to ensure ease of access into theshaft and tunnel for inspection and maintenance purposes. Access formaintenance purposes would be required every three to six months, andonce every ten years when more substantial maintenance works would be

required. Access to the site is proposed off Carnwath Road.


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12.3.9 Tunnel air would be circulated and filtered to avoid it becoming stale. Topromote circulation, air would be extracted out of the tunnel by fans atCarnwath Road Riverside where it would also be filtered. There would bea ventilation building at the site which would house the fans and filters.The building would be approximately 9.5 metres high. After filtering, the

air would be expelled to atmosphere via a separate 15 metre highventilation column located close by. From time to time, when the tunnel isfilling up, air would also be displaced, without help from fans, and expelledvia the same building and ventilation column. In addition, when the tunnelis emptying each site along the route of tunnel has an inlet through whichair can be drawn back into the tunnel. This would require filtering. Thesemeasures would ensure that air released via the ventilation column doesnot contain odour

12.3.10 A brown roof is proposed on the ventilation building. A brown roof isspecifically designed to promote local biodiversity through covering the

roofs of buildings with particular materials. This often comprises rubbleand gravels, which are low in nutrients and promote natural colonisation ofbrown field plant species, which are of particular value to insects andbirds.

Figure 12.4 Carnwath Road Riverside indicative plan of built development


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12.4 Assessment


a. Air quality and odour

b. Ecology aquatic and terrestrial


d. Land quality


f. Socio-economics


h. Transporti. Water resources (ground and surface)

j. Flood risk


12.4.3 As part of the assessment process, consideration has been given toknown major developments that may change future environmentalconditions. To the west of the site on Carnwath Road there is a planningapplication for 150 flats called Baltic Saw Mills. It has been assumed that

this scheme will be completed by 2016. There is also a planningpermission for the Fulham Wharf development, to the east ofHammersmith Bridge Road. This is for a supermarket and 463 dwellings.



12.5.1 The Carnwath Road Riverside site is located within the London Borough ofHammersmith and Fulham Air Quality Management Area. Localmonitoring data indicates that there are currently exceedences of the air

quality standards in the vicinity of the site. The nearest people who may besensitive to the development are occupiers of the nearby residentialdwellings (adjacent to the site and in Carnwath Road and Dymock Street),commercial/leisure premises (adjacent to the site and in the Piper Buildingnorth of the site) as well as pupils and staff

PEIR Non-Technical Summary Part2

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