«LONDONWEST MIDLANDS ENVIRONMENTAL STATEMENT Volume 2 | Community Forum Area report CFA7 | Colne Valley November 2013 ES 220.127.116.11 VOL LondonWest Midlands ...»
3.4.2 In addition, there is a need to avoid or reduce environmental impacts to soils during construction. It is an essential element of the construction process that the soil resources from the areas required temporarily and permanently are stripped and stored so that land required temporarily for construction purposes which is currently in agricultural use can be returned to that use, where agreed and to its pre-existing agricultural condition.
3.4.3 Subject to the adoption of good practice techniques in handling, storing and reinstating soils on land where agricultural or forestry uses are to be resumed, there will be no reduction in the long term capability which would downgrade the quality of disturbed land. Some land with heavier textured soils may require careful management during the aftercare period to ensure this outcome.
3.4.4 Compliance with the draft CoCP will avoid or reduce environmental impacts during construction. Of particular relevance to agriculture, forestry and soils are
the following measures (see Volume 5: Appendix CT-003-000):
the reinstatement of agricultural land which is used temporarily during
construction to agriculture, where this is the agreed end use (draft CoCP:
the provision of a method statement for stripping, handling, storing and replacing agricultural and woodland soils to reduce risks associated with soil degradation on areas of land to be returned to agriculture and woodland following construction, based on detailed soil survey work to be undertaken prior to construction. This will include any remediation measures necessary following the completion of works (draft CoCP, Section 6);
a requirement for contractors to pay due consideration to the impacts of extreme weather events and related conditions which may affect agriculture, forestry and soil resources during construction (draft CoCP, Section 5);
arrangements for the maintenance of farm and field accesses affected by construction (draft CoCP, Section 6);
the protection and maintenance of existing land drainage and livestock water supply systems, where reasonably practicable (draft CoCP, Sections 6 and 16);
the protection of agricultural land adjacent to the construction site, including the provision and maintenance of appropriate stock-proof fencing, where reasonably practicable (draft CoCP, Sections 6 and 9);
Structural disruption is disruption to the existing structure of farm holdings, principally from severance and the loss of key farm holdings.
which will be followed throughout the construction period. The poorly draining Wickham 4 and Essendon soils are more susceptible to compaction and smearing when moved in wet conditions or by inappropriate equipment and need particularly careful handling to avoid damage to soil structure. The better draining Marlow and Coombe 1 soils to the west of the study area will be more resilient to handling.
3.4.14 Compliance with the draft CoCP will ensure the magnitude of impact on soil is low and significance of effect is negligible.
Impacts on holdings 3.4.15 Land may be required from holdings both permanently and temporarily (i.e. the latter just during the construction period). In most cases the temporary and permanent land requirement will occur simultaneously at the start of the Proposed Scheme and it is the combined effect of both that will have the most impact on the holding. In due course some agricultural land will be restored and the impact on individual holdings will reduce, but the following assessment focuses on the combined effect during the construction phase. The residual permanent effects are discussed at the end of this section.
3.4.16 The effects of the Proposed Scheme on individual agricultural and related interests during the construction period are summarised in Table 7. This table shows the total area of land required on a particular holding in absolute terms and as a percentage of the total area farmed. It also shows the area of land that will be returned to the holding following the construction period. The scale of effect is based on the proportion of the holding required rather than the absolute area of land. The holding/reference name provides a unique identifier and relates to Map Series AG-01 (Volume 5, Agriculture, Forestry and Soils Map Book) and Appendix AG-0001-007, Volume 5.
3.4.17 The effects of severance during construction are judged on the ease and availability of access to severed land. For the most part these will be same during and post construction but occasionally they will differ between the two phases. The disruptive effects, principally of construction noise and dust, are assessed according to their effects on land uses and enterprises. Full details of the nature and significance of effects are set out, Volume 5: Appendix AG-001Where the area of land summed by ALC grade differs from the area of land summed by holding, the difference is because some holdings are affected in more than one CFA area and some holdings include non-agricultural land.
Where holdings are affected in more than one CFA the combined impact has been reported in the CFA report where the main holding is located.
CFA Report – Colne Valley/No 7 | Agriculture, forestry and soils Table 7 Summary of temporary effects on holdings during construction
3.4.18 Overall, it is considered that all three holdings will experience temporary major or moderate adverse effects during construction which are significant.
3.4.19 Park Lodge Farm will be particularly affected by the impact of sustainable placement of surplus excavated material which will affect some 24.5ha of the Farm in both this area and into CFA6. However, some of the land that will be affected is presently unavailable for agricultural production due to landfill contamination. This land should become re-available for agricultural production following appropriate restoration and subject to clarification from the Food Standards Agency will be a beneficial effect of the Proposed Scheme; however, this has not been assumed for this assessment.
3.4.20 No farm enterprises that are sensitive to noise or vibration emitted during the construction phase, for example intensive poultry houses, have been identified near to the Proposed Scheme.
Other mitigation measures 3.4.32 Mitigation in other topics that might provide benefits for soils and forestry is discussed in those Sections. Mitigation will incorporate climate change adaptation and resilience measures, as far as practicable.
CFA Report – Colne Valley/No 7 | Agriculture, forestry and soils 3.4.34 Three holdings have been identified that will experience significant permanent effects though all are likely to remain as agricultural businesses. The possible purchase of replacement land using compensation payments has the potential to reduce the effects on individual holdings so they are no longer significant.
Effects arising from operation 3.5 Avoidance and mitigation measures 3.5.1 No measures are required to mitigate operational effects of the Proposed Scheme on agriculture, forestry and soils.
Assessment of impacts and effects 3.5.2 Potential impacts arising from the operation of the Proposed Scheme will
noise emanating from moving trains and warning signals; and the propensity of operational land to harbour noxious weeds.
3.5.3 The potential for significant effects on sensitive livestock receptors from noise has been assessed. No likely significant effects have been identified.
3.5.4 The propensity of linear transport infrastructure to harbour and spread noxious weeds is not only a consequence of the management of the highway and railway land but also of the readiness of weed spread onto such land from adjoining land which could be exacerbated with the effects of climate change.
The presence of noxious weeds, ragwort in particular, will be controlled through the adoption of an appropriate management regime which identifies and remedies areas of weed growth which might threaten adjoining agricultural interests.
Summary of likely significant residual effects 3.5.5 No significant residual effects on agriculture, forestry and soils have been identified for the operation of the Proposed Scheme.
Scope, assumptions and limitations 4.2 4.2.1 The assessment scope, key assumptions and limitations for the air quality assessment are set out in Volume 1, the SMR (Appendix CT-001-000/1), the SMR Addendum (Appendix CT-001-000/2) and appendices presented, Volume 5 (AQ-001-007). This report follows the standard assessment methodology.
4.2.2 The study area for the air quality assessment has been determined on the basis of where impacts on air quality may occur from construction activities, from changes in the nature of traffic during construction and operation or where road alignments have changed.
4.2.3 The assessment of impacts arising from construction dust emissions has been undertaken using the methodology based on that produced by the Institute of Air Quality Management (IAQM)36. It is important to note that this methodology provides a means of assessing the scale and significance of effects that is partly dependent on the approximate number of receptors within close proximity to the dust generating activities. In doing so, it assigns a lower scale of effect to cases where the number of properties is small, e.g. fewer than 10 within 20m of dust generating activities. Thus, a single property very close to a construction site cannot experience a significant effect using this methodology. The assessment presented here reaches a conclusion that PM2.5 and PM10 describe two size fractions of airborne particles that can be inhaled and therefore are of concern for human health. The designations refer to particles of size less than 2.5 and 10 microns in diameter.
IAQM (2012) Guidance on the assessment of the impacts of construction on air quality and the determination of their significance
CFA Report – Colne Valley/No 7 | Air quality
incorporates this concept of significance being dependent on the number of people affected. However, in cases where fewer than 10 properties are within 20m of the construction activity, it will still be the case that mitigation in accordance with the CoCP will be applied.
4.2.4 The assessment of construction traffic impacts has used traffic data that is based on an estimate of the average daily flows in the peak month throughout the construction period (2017-2026). However, the assessment assumes 2017 vehicle emission rates and 2017 background pollutant concentrations. The reason for this is that both pollutant emissions from exhausts and background pollutant concentrations are expected to reduce year by year as a result of vehicle emission controls, and so the year 2017 represents the worst case for the assessment. Furthermore, it has been assumed that the changes in construction traffic will occur for the whole year. In many cases, this represents a conservative assumption, as the duration of the proposed construction works may be much shorter.
Environmental baseline 4.3 Existing baseline 4.3.1 The environmental baseline reported in this section represents the environmental conditions identified within the study area. The air quality in the vicinity of the Colne Valley where the Proposed Scheme related impacts may occur is primarily within air quality standards. However, elevated concentrations occur around the M25 motorway and to the south of the study area in the vicinity of Heathrow and the M4 motorway.
4.3.2 Estimates of background air quality have been obtained from Defra background maps37 for 2012. These data are estimated for 1km grid squares for NOx, NO2, PM10 and PM2.5. These reflect the presence of the M4 and M25 motorways, Heathrow airport and London conurbation, showing elevated concentrations around these areas. Elsewhere, average background pollutant concentrations are within relevant air quality standards. Further details regarding the air quality monitoring are shown, Volume 5: Appendix AQ-001-007.
4.3.3 LBH, South Bucks and Three Rivers Councils all conduct routine monitoring at several locations. However, this monitoring focuses on those areas adversely affected by the M4, M25 and Heathrow, or in urban locations that are away from the Proposed Scheme and which will not be affected by scheme related traffic. On this basis, the monitoring data are not relevant to this assessment and have not been considered.
4.3.4 AQMA have been declared by LBH, South Bucks and Three Rivers Councils, as a result of NO2 concentrations being in excess of the annual average air quality standard (40µg/m3) (see Map AQ-01-007 (Volume 5, Air Quality Map Book)). Whilst some of these are relatively close to the Proposed Scheme, they will not be directly affected by construction activities, traffic or by operational traffic.
4.3.5 Receptors in the area are primarily those residential properties close to construction activity and alongside roads where traffic flows will change as a consequence of Defra (2011) 2010 Based Background Maps for NOx, NO2, PM10 and PM2.5. Available online at: http://laqm.defra.gov.uk/maps/maps2010.html;
Accessed July 2013
CFA Report – Colne Valley/No 7 | Air quality
construction activity or realignment of roads. Notable receptors in close proximity to construction activity are residential properties at Dew’s Farm Cottages, The Tilehouse, Cedar Grange, Denham Grove (De Vere Hotel), Weybeards Cottages and properties on Sunnyhill Road, off Chalfont Lane.
4.3.6 The Mid Colne Valley SSSI ecological receptor is crossed by the route (see Map CT-10-011, Volume 2, CFA7 Map Book) and is sensitive to dust deposition and nitrogen deposition. Fray’s Meadow SSSI is next to the A40 and is potentially affected by the NOx emitted by the additional traffic movements on this road generated by construction.
Future baseline 4.3.7 The data used for the air quality assessment take account of predicted changes in traffic, which are derived from a combination of regional traffic growth factors and consideration of major locally consented schemes, as described in Traffic and Transport, Section 12. In this way, the assessment accounts for cumulative effects.
4.3.8 Appendix CT-004-000 identifies developments with planning permission or sites allocated in adopted development plans, on or close to the Proposed Scheme. These are termed ‘committed developments’ and will form part of the future baseline for the assessment of effects from the construction and operation of the Proposed Scheme.
4.3.9 The potential cumulative impact from committed developments on air quality acting in conjunction with the effects from the construction and operation of the Proposed Scheme have been considered as part of this assessment. This has been achieved by including changes in traffic predicted as a result of the committed developments within the traffic data used for the air quality assessments for construction and operation, in which the future air quality baselines are defined as the ‘without Proposed Scheme scenarios’ at each stage.
Construction (2017) 4.3.10 Future background pollutant concentrations have been sourced from Defra background maps for 2017 which predict NO2 and PM10 levels in 2017 to be lower than in the 2012 baseline.
Operation (2026) 4.3.11 Future background pollutant concentrations have been sourced from Defra background maps for 2026 which predict NO2 and PM10 levels in 2026 to be lower than in the 2012 baseline.