03-Nov-2015

Chiltern Society Assessment of AP4

The easiest way to understand the amendments is to begin with the Non-Technical Summary This gives summaries by Community Forum Area (CFA) of

• Changes to the design and construction assumptions not requiring a change to the Bill
• Changes requiring a change to the Bill

We have provided details of these by CFA for CFA 7, 8, 9, 10. If you need further information, Volume 2 for each CFA provides more details
Here are the links to (some large pdf files - )

CFA 7

Report , Maps and Vol 5 TA

CFA 8

Report , Maps and Vol 5 TA;
Correction to A413-A404 junction assessment (from HS2)

CFA 9

Report , Maps and Vol 5 TA

CFA 10

Report , Maps and Vol 5 TA

Technical Appendices

These give further details to support the CFA reports, and can be found here

The Transport Assessment (Tr-001-000) was reissued on 2nd November 2015. See this page for alterations.

They cover the following topics

• Planning data
• Wider Effects report
• Addendum 4 to EIA Scope and Methodology report
• Air Quality
• Summary of carbon calculation outputs
• Community
• Cultural Heritage
• Ecology
• Electromagnetic interference
• Land Quality
• Landscape and visual assessment
• Sound, noise and vibration
• Transport assessment
• Transport assessment Annexes
• Waste materials
• Water resources
• Water resources – Annex A and Annex B
• Technical appendices off-route

Extracts of changes from Non-Technical Summary

CFA 7 - Colne Valley

Table 4 - Summary of changes to the design and construction assumptions NOT requiring a change to the Bill

• Reduction of 2.6ha of land take at Battlesford Wood / Ranston Covert for viaduct. The land is ancient woodland.
• Utility works at Denham Quarry and Dews Farm. Realigning overhead cables to different pylons – temporary.
• Utility works at Chalfont Lane. Realigning overhead cables to different pylons – temporary
• Construction use of M25 slip roads. Routing of HGVs in the Colne Valley revised. All HGVs using five Colne Valley construction sites will use temporary slip roads between junctions 16 and 17 on the M25. Access to viaduct jetty storage and viaduct storage satellite construction compounds accessed via A40, junction 17 of M25 and A412.

 

Table 24 - Summary of amendments requiring a change to the Bill within CFA 7

• Additional land for amended sustainable placement, and realignment of Footpath U50
• the removal from Bill limits of the permanent placement site in CFA7
• the modification of the permanent sustainable placement site located to the south of the HS2 route, between Breakspear Road and Harvil Road
• the addition of two temporary material stockpiles in CFA7
• diversion of Footpath U50

• Additional land required for temporary  haul road through Uxbridge Golf Course
• Removes construction traffic from A40 Western Avenue, Swakeleys Road and Harvil Road
• Additional Land required for access to Denham Water Ski Club
• 0.2ha of land required to move haul road closer to the viaduct so that crossing controls can be introduced. This will enable the club’s access road to remain open
• Alternative access road to the club to be provided during construction when the current access road cannot be used.

CFA 8 – The Chalfonts and Amersham

Table 25: Summary of amendments within CFA8 requiring a change to the Bill

• Provision for the monitoring and protection of Shardeloes Park (AP4-008-001). The Grade II listed buildings and walls of the kitchen gardens of Shardeloes Park have been identified as being in particularly poor condition. As a result, the Grade II listed buildings will be included in the Bill as authorised to be altered or extended for heritage or monitoring purposes. This will enable it to be monitored during construction.
• Extension to the Chiltern tunnel from Mantle’s Wood portal to South Heath green tunnel north portal and associated works (AP4-009-001). The Chiltern tunnel will be extended by 2.6km from Mantle's Wood, north-west of South Heath, to the location of the South Heath tunnel north portal in the original scheme. The amendment includes changes to the scheme design in CFAs 8, 9 and 10. The changes associated with the extension of the Chiltern tunnel in CFA8 are:
• additional cooling equipment at: Chalfont St Peter, Chalfont St Giles and Amersham ventilation shafts
•    a larger permanent surface area for the Chalfont St Giles ventilation shaft and auto-transformer feeder station to accommodate an express feeder auto-transformer station. 0.13ha of additional land is require during construction and operation which is outside of Bill limits.

Traffic & transport

• The SES reported a moderate adverse effect due to increases in vehicle numbers making it more difficult for pedestrians to cross the A413 Amersham Road, between Joiners Lane and Chalfont St Giles. As a result of the assessment of supplementary traffic data for junctions, it has been identified that this significant effect will not occur.
• The main ES reported a moderate adverse effect due to congestion and delay at the junction of A413/School Lane (Amersham Old Town)/Shardeloes. The SES reported that vehicle users would experience a major adverse effect at this junction, due to higher flows. As a result of the assessment of supplementary traffic data for junctions, it has been identified that this effect will reduce to minor adverse.
• As a result of the assessment of supplementary traffic data for junctions, it has been identified that congestion and delay to vehicle users will result in a new major adverse effect at the junction of A40 London Road/A355 London End.
• As a result of the assessment of supplementary traffic data for junctions, it has been identified that increases in construction traffic will make it more difficult for pedestrians to cross the A40 London Road, between London End and Pyebush Roundabout, resulting in a new major adverse effect.
• The main ES reported a moderate adverse effect on pedestrians as a result of increases in traffic making it more difficult to cross A404 Whielden Lane (between the A413 Amersham Bypass and Whielden Street). The SES reported that this significant effect would be avoided due to changes to the movement of excavated material. However, this was incorrect, as although the movement of excavated material was removed from parts of the A404, this section will continue to be used and the effect reported in the main ES will remain.

Water Resources and Flood Risk Assessment

Effects arising during construction

• The main ES reported that construction of the Chiltern tunnel, including tunnelling and piling/diaphragm wall construction, has the potential to result in a moderate adverse effect on groundwater quality. The main ES reported that until a strategy is agreed with the Environment Agency in consultation with Affinity Water, this effect could occur. Since submission of the main ES, the Environment Agency has updated the source protection zones for a number of public water supply abstractions in the Chilterns area. As a result of this new information it has been identified that the groundwater area is of higher value, resulting in a major adverse effect (as opposed to moderate reported in the main ES).

CFA 9 – Central Chilterns

Table 26: Summary of amendments within CFA9, requiring a change to the Bill

• AP4-009-001: The Chiltern tunnel will be extended by 2.6km from Mantle's Wood, north-west of South Heath, to the location of the South Heath tunnel north portal in the original scheme, with the same horizontal alignment as the original scheme in CFAs 8, 9 and 10;

The amendment includes changes to the scheme design in CFAs 8, 9 and 10. The changes associated with the extension of the Chiltern tunnel in CFA9 are:

• additional cooling equipment at  Little Missenden and Chesham Road vent shafts in CFA9;
• revised design of Little Missenden ventilation shaft and auto-transformer station;
• a new ventilation shaft located adjacent to Annie Bailey’s public house and restaurant with access from B485 Chesham Road (CFA9);
• environmental mitigation proposed in the SES3 scheme will no longer be required between Mantle’s Wood, and the new Chiltern tunnel north portal as the HS2 scheme will tunnel below the woodland (CFA9);
• a 200m porous portal at the new Chiltern tunnel north portal (CFA9);
• realignment of an overhead power line to the west of South Heath (CFA9) which includes the replacement of two pylons with one approximately 11m higher than the existing pylons;
• wider and deeper cutting northwards from the new north portal, compared to the SES3 scheme. The changes to the cutting will require the height of the overbridges to be increased (CFA9 and CFA10);
• the Chiltern tunnel north portal construction compound will be accessed via a haul road to the A413 Missenden Bypass, joining it at the link road (A4128) roundabout. The area will be restored to its former use following the construction works with a permanent access provided from Frith Hill to the new portal (CFA9);
• provision of noise fence barriers approximately 3m high and 1.4km long at the top of the cutting on the eastern side of the HS2 route, extending from the new portal to Leather Lane (CFA9). Integration of the noise fence barriers with landscape earthworks and landscape planting; and
• a midpoint auto-transformer feeder station located on the eastern side of the HS2 route north of Leather Lane with access from Leather Lane (CFA10).
• The amendment will result in an overall net reduction in the land required across CFAs 8, 9 and 10. In particular, the removal of approximately 9ha of ancient woodland from Mantle's Wood, Farthings Wood and Sibley’s Coppice in CFA9 is no longer required
• AP4-009-002: Realignment of diverted Footpath GMI/2 near South Heath
• To avoid Footpath GMI/2 running alongside the HS2 route, the footpath will be diverted to run along the outer edge of a proposed area of landscape planting instead of along the inner edge. This will visually screen the footpath from the HS2 route and reduce the footpath diversion by approximately 20m.

Agriculture, forestry and soils

• The main ES reported moderate adverse effects on Bury Farm due to land required both temporarily and permanently. As part of AP4-009-001, less land will be required temporarily and more land will be required permanently. However the level of significance will remain as reported in the main ES.
• The AP4 revised scheme, will affect fewer agricultural holdings than the original scheme and will remove eight significant adverse temporary effects and five significant adverse permanent effects. One additional agricultural barn demolition is required as part of the amendment at Mulberry Park Hill.

Cultural Heritage

• There will be a different significant effect on Briarwood and artefacts on land between Hedgemoor Wood and Cusden’s Farm, although the level of significance will remain as reported in the main ES. The different significant effects result from the construction activity at the new ventilation shaft at Chesham Road, rather than the construction works for the South Heath cutting, tunnel and associated landscaping associated with the original scheme.

Landscape & Visual
Construction of the extended Chiltern tunnel (AP4-009-001) will result in a new moderate adverse effect on views north-east from Bury Field House, due to the proximity to the satellite construction compound.
Sound, noise and vibration
The main ES reported noise effects in open areas at Hyde Lane, South Heath and Potter Row. However, as a result of the extension of the Chiltern tunnel (AP4- 009-001), this effect will be avoided. (Only to some extent ?? Ed. )

Traffic and transport

• A new major adverse effect will occur on vehicle users as a result of congestion and delay at A413/ Leather Lane.
• The main ES reported a major adverse effect on vehicle users as a result of congestion and delay at the junction of A413 London Road/A4128. This effect was removed by the SES. However, as a result of AP4-009- 001, this will give rise to a major adverse effect.
• The changes to traffic flows associated with AP4-009-001 will result in a new major adverse effect on pedestrians as a result of increases in construction traffic making it more difficult to cross the A413 London Road between B485 Frith Hill/Chesham Road and Rocky Lane.
• The SES reported a moderate adverse effect on pedestrians as a result of construction traffic making it more difficult to cross the B458 Frith Hill/Chesham Road, between King’s Lane and ventilation shaft S5 compound access. Increases in construction traffic associated with AP4-009- 001 will increase this effect to major adverse.
• Increased queues at B485/A413, B485/A4128 are not mentioned in this section
• 50% of spoil from Hunts Green is now routed via the new portal haul road, & North on the A413, increasing traffic on the A413 (but decreasing traffic on Rocky Lane). Ref Vol 5 TR-001-000 para 3.4.17

Water resources and flood risk

• The main ES reported major adverse effects on PWS abstractions TH011 and TH316. Amendment AP4-009-001, with an additional 1km of tunnel located below groundwater level, will give rise to a different significant effect. HS2 Ltd are working with Affinity Water to review the potential effects on water supply and to develop a management strategy. Until a management strategy is agreed this temporary significant effect will remain.
• The construction of the Chesham Road ventilation shaft (as part of AP4-009-001) has the potential to impact on groundwater quality resulting in a different moderate adverse effect on abstraction TH011.

CFA 10 – Dunsmore, Halton and Wendover

Table 5: Summary of changes to the design and construction assumptions not requiring a change to the Bill

• Utility works west of Wendover. Further information found on ground conditions, which will require deep piling for pylons

Table 27: Summary of amendments within CFA 10, requiring a change to the Bill

• Extension of Chiltern Tunnel from Mantles Wood to South Heath north portal AP4-009-001
• Relocation of a mid-point auto-transformer station approximately 150m north of Leather Lane. Land take will be at Hunt’s Green Farm. Permanent Access will be provided from Leather Lane
• Additional land required for the overbridge satellite compound at B4009 Nash Lee Road. AP4-010-001
• Relocate satellite construction compound north of B4009 from south of the road
• Proposed haul road to west of HS2 will relocate to avoid pond south of B4009
• A shorter diversion of Footpath ELL/25will be maintained during construction, reducing the temporary diversion from 650m to 440m
• 0.6ha of additional land outside of the existing limits of the Bill will be required

Agriculture, forestry and soils

• The move of the auto-transformer requires more land at Hunt’s Green Farm, increasing the impact from moderate adverse to major/moderate adverse

Landscape and visual assessment

• Relocation of auto-transformer site will impact views from King’s Lane near Potter Row
• Changes to compound site location at Nash Lee Road will have impact on different LCAs, but overall will be of a similar impact.

Traffic and transport

• Difficulty crossing King’s Lane between Rocky Lane and Bowood Lane. A haul road from Chiltern Tunnel north to Bowood Lane overbridge satellite construction compound will reduce traffic on King’s Lane
• Difficulty crossing Rocky Lane between A413 and Rocky Lane underbridge construction site. The Chiltern Tunnel extension will reduce the number of HGVs on Rocky Lane
• Chiltern Tunnel extension    major adverse effect on pedestrians crossing  A413 between B485 and Rocky Lane
• ES reported a major adverse effect on users at junction of A413 with Dunsmore Lane. With the Chiltern Tunnel extension this will remain.
•  ES reported a major adverse effect on users at junction of A413 with Bowood Lane. With the Chiltern Tunnel extension this will remain.

Off-Route Effects

Table 42: Summary of off-route amendments, requiring a change to the Bill

• Additional land required for ecological mitigation at Langley – AP4-000-001
• Approx 18ha of additional land. This is north of Grand Union Canal, approx. 380m North-west of Heathrow Express depot site. Land is outside the limits of the Bill
• Footpath WEX/13/2 will temporarily diverted or closed during creation of ecological area. 400m increased travel distance

Volume 3: Route-wide effects - Summary

Chilterns AONB

• Effects arising during construction – Claims that impact on Misbourne  Valley goes from major adverse to moderate adverse
• Effects arising during operation - Claims that impact on Misbourne  Valley goes from major adverse to moderate adverse.

Ecology

• AP4 will result in habitat loss or fragmentation from 3 SSSIs and 1 local nature reserve.
• Local Wildlife Sites – 3 LWS saved by Chiltern Tunnel extension. 3 other LWS impaced through additional land take.
• Ancient Woodland – Sites impacted reduced from 37 to 32 reducing the loss by 12.4 ha.

Waste and Material Resources

• Surplus excavated material – for off-site disposal increases to 12,573,420 Mt from 11,311,251 Mt.
• Non Hazardous Waste – increase of 22,108 Mt to 852,562 Mt
• Hazardous Waste – increase of 1,784 Mt to 539,193 Mt

Agriculture, forestry and soils

• Good quality land required for Heathrow Express Depot at Langley increased to 24ha

Cultural Heritage

• Ecological Provision at Langley will require part of Langley Park, first mapped in 1603

Traffic and transport

• Impact on Footpath WEX/13/2