2 Other Works

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As well as requiring sites to build and operate theinterception o combined sewer overows (CSOs), theirconnection tunnels and the main tunnel, there will be otherworks associated with the Thames Tunnel project. Theseinclude connections to the northern Low Level Number 1Sewer, other minor sewer modifcations and saety accesspoints. This Project Inormation Paper also covers thedierences in interception o the Charlton CSO that dependon the main tunnel route.

Other worksOtherwo

rks

Low Level Sewer connectionsWe have reduced the number o proposedconstruction sites by controlling some combinedsewer overfows (CSOs) without having to carry

out major engineering works on the CSO itsel.The Environment Agency identied 34 CSOsthat are considered unacceptable because othe requency o their discharges or the adverseenvironmental impact that they have on theRiver Thames. However, this does not mean thatwe need 34 dierent CSO sites across Londonbecause we will be able to substantially reducethe overfows rom some CSOs by carryingout works at other sites that we already need,or by making minor modications inside the

sewerage system.

The low level sewers are the backbone oLondons Victorian sewerage system, runningbroadly parallel to the River Thames and carryingsewage to either Beckton Sewage TreatmentWorks (north o the river) or Crossness SewageTreatment Works (south o the river).

We propose to make connections to the northernlow level sewer at three o our CSO sites ChelseaEmbankment Foreshore, Victoria EmbankmentForeshore and Blackriars Bridge Foreshore. We

already have to carry out work at these threesites to connect the local CSOs to our tunnel. Bymaking an additional connection to the low levelsewer at these three locations, it means thatwe do not have to construct major works suchas shats, interception chambers or connectingtunnels or the ollowing CSOs:

Church Street CSO

Queen Street CSO

Smith Street CSO

Western Pumping Station CSO

Kings Scholars Pond Storm Relief CSO

Grosvenor Ditch CSO

Northumberland CSO

Savoy Street CSO

Norfolk Street CSO

Essex Street CSO

Thames Tunnel


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Minor system modifcationsBy making minor modications to our seweragesystem, including changing how some o ourpumping stations operate or adjusting the heighto weirs that allow fows to divert rom one sewerto another, we can also control the fows rom theollowing CSOs without the need or interceptionworks:

Stamford Brook CSO

North West Storm Relief CSO Charlton Storm Relief CSO

Based on our current level o design, we anticipatethat minor modications will be needed at thelocations shown in the plans above. Further designand investigations are required to conrm thedetails, and we will be presenting our more detailedproposals in our second round o consultation beorethe submission o planning applications.

Modifcations (on plan above): (1) West Putney CSO at the existing weir between

the local sewer and the West Putney Storm RelieSewer along Upper Richmond Road.

(2) Jews Row CSO at the overow arrangement atthe connection between the Wandle Storm RelieSewer with the southern Low Level Number 1 Sewerat Birdhurst Road.

(3) Jews Row CSO at the overow arrangement at

the connection between the Wandle Storm RelieSewer with the southern Low Level Number 2 Sewerat Wandsworth Common West Side.

Map showing sites 1 to 3

Ordnance Survey Licence number 100019345. Crown Copyright 2009. All rights reserved.


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Map showing sites 4 and 5

Modifcations (on plan above): (4) Savoy Street CSO chamber

(5) Shad Thames Pumping Station regradingof the sewer between Druid Street and thepumping station.



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Map showing sites 6 to 8

Holloway CSO at the three existingoverfow weirs (see above),

(6) 162 Stroud Green Road,

(7) the junction of Stroud Green Roadand Tollington Park,

(8) and the junction of Mildway Road,King Henrys Walk and Crossway.



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Charlton Storm Relie CSO dierencesdepending on the main tunnel routeThe 13 CSOs listed above require no directinterception works to be carried out i the maintunnel route goes to Abbey Mills Pumping Stations.Twelve o these CSOs would also require no directinterception or both the main tunnel routes toBeckton Sewage Treatment Works, but CharltonStorm Relie CSO would be intercepted as the maintunnel would pass very close to the CSO, and a shat

on the line o the main tunnel would be required.

These are the sites that we considered or connectingthe Charlton Storm Relie CSO to the tunnel:

Site 1 Foreshore, near Thames Barrier

This site is in the oreshore at the outlet o the CSO inront o the Tarmac aggregate processing plant andan indoor go-karting centre.

Site 2 Tarmac aggregate plant, Herringham Road

This site is currently used as an aggregate processing

plant, making use o the jetty acilities and conveyorsover the Thames Path.

Had either the River Thames route or theRotherhithe route been the preerred main tunnelroute, then this site would have been the preerredCSO site to intercept Charlton Storm Relie CSO.

Site 3 Depot, junction Herringham Road and New

Lyndenburg Street

This site is currently occupied by a recycling businessand is used or storage o recycled materials such aspaper. It is not large enough as a site on its own, buthas been considered as a site in combination withSite 4.

Site 4 Recycling plant, New Lyndenburg Street

This site is currently occupied by a recycling businessand is used or storage and handling o recycledmaterials such as paper and plastic. It is not largeenough as a site on its own, but has been consideredas a site in combination with Site 3.

Site 5 Stone Foundry, access road o Woolwich Road

This site is currently occupied by a magnesium andaluminium casting actory.

Charlton Storm Relie showing preerred and shortlisted sites



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Saety access pointsAccess is required to the main tunnel and connectiontunnels periodically or inspection and maintenancepurposes, which is anticipated to take place onceevery ten years. Access into the tunnels will beprovided at the shats used to build the main tunneland at the CSO drop shats. I these access points aretoo ar apart or sae working then additional shatswill need to be provided, known as saety accesspoints.

The inrequent entries into the main tunnel orinspection and maintenance will be by specialisedvehicle and thereore access points can be atconsiderable distances apart. It is anticipated thatthe shats used to build the main tunnel and theCSO drop shats that are on the line o the maintunnel will provide sucient access points or themain tunnel. Thereore no saety access points areanticipated on the main tunnel or any o the threetunnel route options.

The entries into the smaller connection tunnels willbe on oot, and thereore shorter distances betweenaccess points are required or sae working. Access willbe provided via the CSO drop shats and main tunnelshats used to build the connection tunnels. However,it is anticipated that these will not provide sucientaccess points in all cases and saety access pointswill thereore be required in a ew situations wherethe distance between the shats on the connectiontunnels are too great.

The construction works or these ancillary saetyaccess points on connection tunnels will besignicantly less than or CSO sites and main tunnelshat sites as only the building o a shat will berequired. At this stage in the design, the locationsor the saety access points have not been identied,because they depend on the nal selection o sitesor CSO interception and main tunnel shats, andthereore these will be determined at a later stage.

For urther project inormation see our website:

www.thamestunnelconsultation.co.uk

or call us on 0845 366 2950

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2 Other Works