«LONDONWEST MIDLANDS ENVIRONMENTAL STATEMENT Volume 2 | Community Forum Area report CFA7 | Colne Valley November 2013 ES 188.8.131.52 VOL LondonWest Midlands ...»
Effects arising during construction 4.4 Avoidance and mitigation measures 4.4.1 Emissions to atmosphere will be controlled and managed during construction through the route-wide implementation of the CoCP, where appropriate. The draft CoCP includes a range of mitigation measures that are accepted by the IAQM as being suitable to reduce impacts to as low a level as reasonably practicable. It also makes provision for the preparation of Local Environmental Management Plans (LEMP) which will set out how the project will adapt and deliver the required environmental CFA Report – Colne Valley/No 7 | Air quality and community protection measures within each area through the implementation of specific measures required to control dust and other emissions from activities in the area.
4.4.2 The assessment has assumed that the general measures detailed in Section 7 of the
draft CoCP (Volume 5: Appendix CT-003-000) will be implemented. These include:
contractors being required to manage dust, air pollution, odour and exhaust emissions during construction works;
inspection and visual monitoring after consultation with the local authorities to assess the effectiveness of the measures taken to control dust and air pollutant emissions;
cleaning (including watering) of haul routes and designated vehicle waiting areas to suppress dust;
keeping material stockpiles away from sensitive receptors where reasonably practicable taking into account the prevailing wind direction relative to sensitive receptors;
using enclosures to contain dust emitted from construction activities; and undertaking soil spreading, seeding and planting of completed earthworks as soon as reasonably practicable following completion of earthworks.
Assessment of impacts and effects Temporary effects 4.4.3 Impacts from the construction of the Proposed Scheme could arise from dustgenerating activities and emissions from construction traffic. As such, the assessment of construction impacts has been undertaken for human receptors sensitive to dust and exposure to NO2 and PM10, as well as ecological receptors sensitive to dust and nitrogen deposition.
4.4.4 An assessment of construction traffic emissions has also been undertaken for two scenarios in the construction period, a without the Proposed Scheme scenario and a with the Proposed Scheme scenario.
4.4.5 In the Colne Valley area, there will be the potential for dust emission at demolition sites, construction sites and at the sustainable placement area. In particular, areas of construction activity will be located at the Chiltern tunnel south portal, the Colne Valley viaduct and where cuttings and embankments are required along the route.
The haul route used for the disposal of excavated material is also a potential source of dust.
4.4.6 Given the mitigation contained within the draft CoCP, including the use of LEMP to minimise the impacts at receptors close to the haul route, the assessment of impacts on all receptors arising from dust emissions has concluded that they will be negligible in magnitude and that the effect will not be significant. The basis for this conclusion can be found, Volume 5: Appendix AQ-001-007, which describes the magnitude of the emissions and their proximity to receptors.
CFA Report – Colne Valley/No 7 | Air quality
4.4.7 Construction activity could also affect local air quality through the additional traffic generated on local roads as a result of construction traffic routes and changes to traffic patterns arising from temporary road diversions.
4.4.8 Examination of the changes in traffic flows for 2017 along the affected roads has identified some roads that meet the criteria set out in Volume 1 of the SMR (Appendix CT-001-000/1) for an assessment. This assessment found that there will be substantial adverse impacts along Swakeleys Road, between Harvil Road and the A40, at a number of receptors assessed for NO2 (for more information see Volume 5, Appendix AQ-001-007). It identified that there will be negligible impacts at a number of receptors for PM10 and PM2.5. The moderate impacts are significant effects for receptors, although of limited spatial extent and population exposure.
4.4.9 The assessment has also found that increases in NOx concentrations in the Mid Colne Valley SSSI within 100m from the road would give rise to potentially significant effects. No significant effects from nitrogen were identified. The increase in NOx concentrations is relatively small, in comparison to the background, will be of limited duration and will affect a small part of the SSSI. This is not likely to be a significant effect on the integrity of the SSSI.
4.4.10 A potentially significant effect was also identified in respect of NOx concentrations on those parts of Fray’s Farm Meadows SSSI within 200m of the road, taking into account background concentrations of NOx and a potentially significant effect in respect of nutrient nitrogen deposition was predicted within 50m of the road. The increase in nitrogen deposition is potentially significant only for a very small fraction of the SSSI and will be of limited duration. It is highly unlikely to be a significant effect on the integrity of the SSSI. Only a small part of the SSSI at its southern extent is adjacent to the A40 in any event and most of its southern boundary is approximately 100m from the roadside. The increase in NOx concentrations are relatively small in comparison with background concentrations and affect only a small part of the SSSI.
It is highly unlikely that this impact could affect the integrity of the SSSI and is therefore not significant.
Permanent effects 4.4.11 There are no permanent effects anticipated to arise during construction of the Proposed Scheme.
Other mitigation measures 4.4.12 No other mitigation measures during construction are proposed in relation to air quality in this area.
Cumulative effects 4.4.13 The construction dust assessment has considered the potential cumulative air quality effects of the Proposed Scheme and other committed developments. The traffic data used for the assessment include the traffic changes expected from the committed developments and therefore their impacts have been included within the assessment.
CFA Report – Colne Valley/No 7 | Air quality
Summary of likely significant residual effects 4.4.14 The methods outlined within the draft CoCP to control and manage potential effects of construction dust are considered effective in this location and no significant residual effects are considered likely. Receptors on Swakeleys Road will experience substantial adverse effects for NO2 concentrations as a result of construction traffic movements.
4.4.15 Properties on Swakeleys Road between Harvil Road and the A40 are expected to experience temporary substantial adverse impacts related to NO2 concentrations during construction that will be significant.
Effects arising from operation 4.5 Avoidance and mitigation measures 4.5.1 No mitigation measures are proposed during operation in relation to air quality in the area.
Assessment of impacts and effects 4.5.2 Impacts from the operation of the Proposed Scheme will relate to changes in the volume, composition and distribution of road traffic. There are no direct atmospheric emissions from the operation of trains that will cause an impact on air quality and these have therefore not been assessed.
4.5.3 The assessment of operational traffic emissions has been undertaken for two scenarios in the operation year 2026, a without the Proposed Scheme scenario and a with the Proposed Scheme scenario. The traffic data include the additional traffic from any future committed developments.
4.5.4 Traffic data in the Colne Valley area have been screened to identify roads that require further assessment and to confirm the likely effect of the change in emissions from vehicles using those roads in 2026.
4.5.5 No roads met the criteria for further assessment outlined in the SMR (Appendix CT-001-000/1) and therefore, no significant effect associated with the scheme is predicted.
Other mitigation measures 4.5.6 No other mitigation measures are proposed in relation to air quality in this area during operation.
Cumulative effects 4.5.7 The traffic data used for the assessment include the traffic changes expected from the committed developments and therefore their impacts have been included within the assessment Summary of likely significant residual effects 4.5.8 No significant residual effects are anticipated for air quality in this area during operation of the Proposed Scheme.
Introduction5.1 5.1.1 This section reports the impacts and likely significant effects on local communities resulting from the construction and operation of the Proposed Scheme.
5.1.2 Key issues concerning the community assessment for this study area comprise:
impacts on users of HOAC;
loss of land within Colne Valley Regional Park;
temporary re-routing of the Colne Valley Trail, Hillingdon Trail and South Bucks Way where they will be intersected by the construction activity and the temporary closure of part of Old Shire Lane circular walk; and impacts on users of Denham Waterski Club.
5.1.3 Further details of the community assessments and write-ups of open space surveys
and recreational PRoW surveys undertaken within this area are contained, Volume 5:
5.1.4 Significantly affected community resources are shown on Maps CM-01-023 to CM-01-025 (Volume 5, Community Map Book).
5.1.5 The current assessment draws upon information gathered from local and regional resources including HOAC, Buckinghamshire County Council and Denham Waterski Club.
Scope, assumptions and limitations 5.2 5.2.1 The assessment scope, key assumptions and limitations for the community assessment are set out in Volume 1, the SMR (see Volume 5: Appendix CT-001-000/1) and the SMR Addendum (see Volume 5: Appendix CT-001-000/2). This report follows the standard assessment methodology.
5.2.2 Construction worker accommodation will be located at Colne Valley viaduct main compound and the Chiltern tunnel main compound. Construction worker impacts on community resources are considered at a route wide level in Appendix CM-002-000.
The assessment takes into account the number of workers, the type and location of accommodation, working hours, facilities provided on construction compounds, experience from other large projects (such as HS1) and the measures contained in the draft CoCP. On this basis it is concluded that there will be no significant effects associated with construction worker accommodation.
Environmental baseline 5.3 Existing baseline 5.3.1 Baseline data on community resources was collected up to 1km from the centre line of the Proposed Scheme and, additionally, up to 250m from the area of land required for construction.
CFA Report – Colne Valley/No7 | Community 5.3.2 The study area includes the area of land required both temporarily and permanently for the construction and operation of the Proposed Scheme together with a wider corridor within which receptors or resources could be affected by a combination of significant residual effects, such as noise, vibration, construction dust, poor air quality and visual intrusion. In addition, the study area has regard to the proposed routeing of construction traffic and takes account of catchment areas for community facilities which could be affected where crossed by the Proposed Scheme. This area includes land between Harvil Road and Moorhall Road, land around A412 Denham Way/North Orbital Road and land surrounding West Hyde and Maple Cross. The area is part of the suburban fringe of London and includes the settlements of South Harefield, Denham Green, West Hyde and Maple Cross and incorporates the Colne Valley Regional Park.
Harvil Road to Moorhall Road 5.3.3 The area between Harvil Road and Moorhall Road is dominated by the lakes of the Colne Valley and intervening woodland and fields. A small housing estate is located at the junction between Harvil Road and Moorhall Road at the southern edge of South Harefield. There are also several properties including Dew’s Farm and Dew’s Farm Cottages outside the village, which are located on the east bank of Harefield No.2 Lake in the Colne Valley. Community facilities located near South Harefield include HOAC, Uxbridge Golf Club and Bayhurst Wood Country Park.
A412 Denham Way/North Orbital Road 5.3.4 The A412 Denham Way/North Orbital Road passes through the villages of Denham Green and Denham Garden Village. The villages are located to the south-west of South Harefield on the western bank of the Broadwater Lake. Shops and services are located in the vicinity of Denham Way, where the A412 passes through the villages.
Other community facilities include village halls, public houses, St Mark’s Church and Hall on Green Tiles Lane, Tilehouse County School, Denham Medical Centre on Queen Mother’s Drive, Denham Green Dental Practice on Penn Drive and a post office off Denham Green Close. Denham Waterski Club is located on A412. A number of PRoW pass through the Colne Valley Regional Park including the Colne Valley Trail and Hillingdon Trail along the banks of the Grand Union Canal as well as Old Shire Lane Circular Walk and the South Bucks Way.
West Hyde and Maple Cross 5.3.5 West Hyde and Maple Cross are small settlements on the western banks of the lakes and north-west of Harefield. West Hyde is the smaller of the two settlements and is centred on Chalfont Lane and Old Uxbridge Road. There are some community facilities within West Hyde and Maple Cross. These are all located on Old Uxbridge Road and include St Thomas Church and its associated churchyard, the Royal Oak public house, allotments south of Chalfont Lane and the West Hyde and Maple Cross Youth Centre.
5.3.6 Maple Cross is situated between the M25 and A412 Denham Way/North Orbital Road.
Maple Cross has some community facilities including shops, Maple Cross Junior Mixed Infants (JMI) and Nursery School, public houses and playing fields.
CFA Report – Colne Valley/No7 | Community
Future baseline Construction (2017) 5.3.7 Volume 5: Appendix CT-004-025/1 provides details of the developments which are assumed to have been implemented by 2017. No committed developments have been identified in this area that will materially alter the baseline conditions in 2017 for the community.
Operation (2026) 5.3.8 The review of future baseline conditions has not identified any additional committed developments, within the study area, which will be completed by the year of operation.
Effects arising during construction 5.4 Avoidance and mitigation measures 5.4.1 The following measures have been incorporated into the scheme design as part of the design development process to avoid or minimise the adverse environmental impacts
the configuration of the Colne Valley viaduct laydown satellite compound will reduce impacts on Denham Waterski Club; and areas of sustainable placement in this area and CFA6 to avoid effects on Harvil Road, Swakeleys Road and the A40 Western Avenue.
5.4.2 The draft CoCP includes a range of provisions that will help mitigate community
effects associated with construction within this area, including:
appointment of community relations personnel (draft CoCP, Section 5);
community helpline to handle enquires from the public (draft CoCP, Section 5);
sensitive layout of construction sites to minimise nuisance (draft CoCP, Section 5);
where reasonably practicable, maintenance of PRoW for pedestrians, cyclists and equestrians around the perimeter of construction compounds and across entry and exit points (draft CoCP, Section 5);
a requirement for contractors to pay due consideration to the impacts of extreme weather events and related conditions which may affect community resources during construction (draft CoCP, Section 5);