Proposal for Northern Extension of Northolt Tunnel sift report
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- Bu səhifədəki naviqasiya:
- Location: Colne Valley Option name and description: Community Forum Request for Northolt Tunnel Extension
- Tunnel with Heathrow Spur Provision Tunnel without Heathrow Spur Provision Headings Appraisal criteria
- QUALITATIVE IMPACT ASSESSMENT and/or QUANTITIVE ASSESSMENT RATIN G
- Overall Rating
- 9 Environmental Appraisal Template
- (Northolt Tunnel to West Ruislip/ Viaduct across the Colne Valley/ Chiltern tunnel east of M25 between jnc 16 and 17) Option B
- Option C As per option B but with no passive provision for a connection to Heathrow
- QUALITATIVE IMPACT DESCRIPTION and/or QUANTITIVE ASSESSMENT RATI NG
`Code 1 -
Accepted Uncontrolled when printed INTERNAL INFORMATION Northern Extension of Northolt Tunnel SIFT Report
C222-ATK-DS-REP-020-000034 Revision – P06
Page 43
Uncontrolled when printed INTERNAL INFORMATION
HS2 Operation Feasibility - Passengers Assess Passenger Dispersal covering road (right of way), rail and public transport
N/A 0 N/A 0 N/A
0 Demand
Likely Relative Passenger Numbers Likely Journey Times Likely Demand N/A
0 Slightly increased journey times due to tunnelled alignment and Heathrow spur turnouts. - Slightly increased journey times due to tunnelled alignment. - Costs
Estimated whole life cycle costs to give relative assessment N/A 0
likely to be significantly higher cost. --- Excavated material management, operation and maintenance, all likely to be significantly higher cost.
Estimated initial capital costs to give relative assessment (The capital costs include construction, land and compensation costs) N/A
0 Excavated material management, operation and maintenance, all likely to be significantly higher cost. Procurement of TBMs will incur a high cost. Cost estimate: additional £215.0 million. --- Excavated material management, operation and maintenance, all likely to be significantly higher cost. Procurement of TBMs will incur a high cost. Cost estimate: additional £185.1million. --- Environment Input from ENVIRONMENTAL APPRAISAL MATRIX See separate environmental assessment 0 See separate environmental assessment. +++
See separate environmental assessment +++
Safety Assess the relative safety during construction, Safety risks associated with viaduct – working at height and over water. 0 Safety risks associated with bored tunnels - working in confined space - Safety risks associated with bored tunnels - working in confined space - Assess the relative safety during Operations, maintenance and decommissioning , and Emergency access
Safety risks associated with bored tunnels- operation and maintenance in confined space
Safety risks associated with bored tunnels- operation and maintenance in confined space
Commitments Previous explicit or implicit public assurances or commitments to third parties
N/A 0 Possibility of increased programme duration - this would impact on commitment to open HS2 in 2026. However avoids the need for utilities diversions and relocation of businesses during construction (HOAC) 0
commitment to open HS2 in 2026. However avoids the need for utilities diversions and relocation of businesses during construction (HOAC) 0
Development Does the option provide opportunities for development in particular for over station development N/A 0
0 N/A
0
Overall Rating 0
--- Overall Rating --- Preferred Option: Option A Reason: Cost, programme implications, construction safety, major traffic movements for the removal of tunnel excavated material.
`Code 1 -
Accepted Uncontrolled when printed INTERNAL INFORMATION Northern Extension of Northolt Tunnel SIFT Report
C222-ATK-DS-REP-020-000034 Revision – P06
Page 44
Uncontrolled when printed INTERNAL INFORMATION
Key Sustainability Issue Topic STAGE: Constructio n or Operation EDA Considered (incl. Topic and Ref no.) Comment QUALITATIVE IMPACT DESCRIPTION and/or QUANTITIVE ASSESSMENT RATI NG QUALITATIVE IMPACT DESCRIPTION and/or QUANTITIVE ASSESSMENT RATI NG QUALITATIVE IMPACT DESCRIPTION and/or QUANTITIVE ASSESSMENT RATI NG Greenhouse gas emissions and climate change Climate adaptability Const
N/A Not assessed N/A Not assessed N/A Op
Not assessed N/A Not assessed N/A Not assessed N/A Greenhouse gas emissions Const
N/A Not assessed N/A Not assessed N/A Op
Not assessed N/A Not assessed N/A Not assessed N/A Energy use Const
Not assessed N/A Not assessed N/A Not assessed N/A Op
Not assessed N/A Not assessed N/A Not assessed N/A Natural and cultural resource protection and environmental enhancement Landscape/ townscape Const LV3 and LV6 The viaduct and associated embankments, cuttings and tunnel portals are not within any listed landscape areas; however the intricate mosaic of water features and woodland blocks of the Colne Valley gives the area a distinctive landscape characteristic and make up the bulk of the Colne Valley Regional Park.
There are a large number of residential, recreational and commercial receptors that may suffer visual impact due to the viaduct construction, these include (but are not limited to) residents of Denham, Denham Green and South Harefield. Recreational users of the Colne Valley lakes, local footpaths, the River Colne and Grand Union Canal with associated marina. Users and employees of the Hillingdon Outdoor Activity Centre, local golf courses, Denham Aerodrome, Denham Grove (De Vere Hotel) and rail/road users.
1.1.1
There are two ancient woodlands (Ranston Covert and Battlesford Wood) which will be directly impacted by the o
construction over the base case as the majority of this option would be in tunnel.
Construction of the additional three vent shafts would have a local impact on the landscape and visual character of these areas.
The 700m long ‘gap’ structure, located close to the Chiltern tunnel south portal and cutting of the base case, would have a broadly similar direct impacts, although considerably more excavated material would be handled at this location as a consequence of the extension of the Chiltern tunnel.
There may be localised adverse visual impacts caused by the T3 vent shaft during construction.
1.1.2 There would be reduced adverse impact from there not being a requirement for construction activity relating to the National Grid pylon diversion. +++ As Option B. With the lack of the Heathrow Spur there may be reduced impact from a lessor quantity of excavated material being stockpiled within the main compound.
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