«LONDONWEST MIDLANDS ENVIRONMENTAL STATEMENT Volume 2 | Community Forum Area report CFA7 | Colne Valley November 2013 ES 220.127.116.11 VOL LondonWest Midlands ...»
Assessment of impacts and effects 8.5.3 The Ickenham auto-transformer feeder station and the National Grid feeder station will be located at the eastern end of the study area close to the site currently used by HOAC and an auto-transformer station located at West Hyde. An auto-transformer station can, in principle, be a source of contamination through accidental discharge or leaks of coolant. However, the proposed auto-transformer stations, in common with other modern substations, will use secondary containment appropriate to the level of risk.
8.5.4 The operation of the trains may give rise to minor contamination through leakage of hydraulic or lubricating oils. However, such leakage or spillage is expected to be very small and unlikely to result in significant contamination.
8.5.5 It is unlikely that there will be any cumulative effects on land quality receptors due to the environmental controls that will be placed on operational procedures.
Other mitigation measures 8.5.6 No other land quality mitigation measures beyond those already outlined are considered necessary in the Colne Valley area.
8.5.7 There will be on-going monitoring requirements, as appropriate following remediation works carried out during construction. Such monitoring, including monitoring of groundwater quality or ground gas, could extend into the operational phase of the Proposed Scheme.
Summary of likely significant residual effects 8.5.8 No significant residual effects are anticipated associated with the operation of the Proposed Scheme.
9 Landscape and visual assessment
Introduction9.1 9.1.1 This section reports the assessment of the likely significant landscape and visual effects. It starts by summarising the baseline and future conditions found within and around the route of the Proposed Scheme and goes on to describe the significant effects that will arise during construction and operation on landscape character areas (LCA) and visual receptors.
9.1.2 In this section, the operational assessment refers not just to the running of the trains but also the presence of the new permanent infrastructure associated with the Proposed Scheme.
9.1.3 Principal landscape and visual issues in the area include:
temporary effects to LCA and visual receptors during construction arising from the presence of construction plant, construction compounds, demolition, temporary overhead power lines and pylon diversions, removal of existing vegetation, temporary access routes, earthworks and stockpiles and severance of agricultural land; and permanent landscape and visual effects during operation arising from the presence of new engineered landforms within the existing landscape. These will include a viaduct, embankments, Proposed Scheme in cutting, tunnel portal, highway infrastructure, noise fence barriers, overhead power line diversions, auto-transformer feeder stations, auto-transformer stations, a sustainable placement area and regular passing of high speed trains. The majority of permanent effects will reduce over time as planting established as part of the Proposed Scheme matures. This is with the exception of the diverted overhead power line, Colne Valley viaduct and associated passing high speed trains which will remain prominent in certain locations.
9.1.4 A separate but related assessment of effects on the setting of heritage assets is included in Section 6 Cultural Heritage. Further details on the landscape and visual assessment, including engagement, baseline information and assessment findings,
are presented, Volume 5: Appendix LV-001-007 which comprises the following:
Part 1 Engagement with technical stakeholders;
Part 2 Environmental baseline report;
Part 3 Assessment matrices; and Part 4 Schedule of non-significant effects.
9.1.5 The extent of the landscape and visual study area, the distribution of visual receptor viewpoints and the location of verifiable photomontages has been discussed with Three Rivers District Council, South Bucks District Council, Chiltern District Council, Natural England and LBH. Summer field surveys, including photographic studies of LCA and visual assessment of viewpoints, were undertaken from June to August 2012 CFA Report – Colne Valley/No7 | Landscape and visual assessment
Scope, assumption and limitations 9.2 9.2.1 The assessment scope, key assumptions and limitations for the landscape and visual assessment are set out in Volume 1, the SMR (Volume 5: Appendix CT-0001-000/1) and the SMR Addendum (Volume 5: Appendix CT-0001-000/2). This report follows the standard assessment methodology.
9.2.2 The study area has been informed by the construction and operational phase zones of theoretical visibility (ZTV), which are shown on Maps LV-07-024b to LV-07-027a and LV-08-024b to LV-08-027a (Volume 5, Landscape and Visual Assessment Map Book).
The ZTV has been produced in line with the methodology described in the SMR Addendum (Volume 5: Appendix CT-001-000/2) and is an indication of the theoretical visibility of the Proposed Scheme. In some locations, extensive vegetation cover will mean the actual visibility is substantially less than that shown in the ZTV. Tall construction plant (e.g. cranes and piling rigs) are excluded from the ZTV for the construction phase and overhead line equipment is excluded from the ZTV for the operational phase, but these are described and taken in to account in the assessment of effects on landscape character areas and visual receptors.
9.2.3 LCA and visual receptors within approximately 500m of the Proposed Scheme have been assessed. Long distance views of up to 1.5km have been considered at locations such as Mount Pleasant, west of Harefield and the nearby PRoW.
Limitations 9.2.4 During the baseline survey there were some areas which were inaccessible (such as private land, commercial premises and residential buildings). In several areas PRoW were also inaccessible due access being restricted by the owner/occupier. In these instances, professional judgement has been used to approximate the likely views from these locations.
Environmental baseline 9.3 Existing baseline Landscape baseline 9.3.1 The settlement pattern in the Colne Valley is relatively sparse, although the valley is more densely developed to the south. On the valley sides mixed farmland is a dominant feature within the landscape. The corridors of open space that follow the River Colne, Grand Union Canal and the lakes that these waterways support are dominant landscape features in the valley bottom. There is concentrated residential and industrial development around Uxbridge. The Chiltern Main Line spans the Colne Valley and has a distinctive influence upon settlements along its route; either forming a perimeter boundary to urban development or travelling directly through the settled area, forming a green corridor due to adjacent line-side vegetation. The M25 corridor is a major urban feature within the landscape to the west of the area. A number of conservation areas, registered parks and gardens and listed buildings are located within the area. The vegetation patterns within the area comprise woodland, scrub CFA Report – Colne Valley/No7 | Landscape and visual assessment and meadow within open space, trees and shrubs within river corridors, hedgerows including Old Shires Way ancient hedgerow and small woodlands.
9.3.2 The LCA have been determined with reference to the Buckinghamshire Landscape Character Assessment and Hertfordshire Landscape Character Assessment.
9.3.3 Descriptions of all LCA are provided, Volume 5: Appendix LV-001-007 Part 2. For the purposes of this assessment the study area has been sub-divided into ten discrete LCA, six of which are most likely to be affected. A summary of these LCA is provided below. The LCA are shown on Maps LV-02-024b to LV-02-027a (Volume 5, Landscape and Visual Assessment Map Book).
Harefield Farmland Valley Slopes LCA 9.3.4 Land use is predominantly agricultural, with regular shaped, small to medium sized fields of pasture and some pockets of arable farmland. There are some areas of woodland, including Newyears Green Covert and Copthall Covert and many of the fields are bordered by hedgerows and hedgerow trees. Buildings comprise a mix of isolated two storey detached farmhouses and associated working buildings, such as barns and sheds. The existing Chiltern Main Line overhead power lines and other infrastructure detract from the overall quality of the area. However, the presence of hedgerows and woodland blocks help to integrate some of these elements. Managed and maintained elements within the wider landscape include golf courses, Bayhurst and Ruislip Woods National Nature Reserves and Harefield Place registered park and garden. Overall the landscape is relatively well maintained resulting in a fair condition.
Extensive open space and widespread tree cover provides a sense of seclusion. Given the presence of the Chiltern Main Line embankment in the east of the LCA, tranquillity is considered to be medium. This LCA is located within green belt and is of regional value. Therefore, this area has a high sensitivity to change.
Colne River Valley LCA 9.3.5 The River Colne and the Grand Union Canal pass through the valley and are bordered by dense vegetation. The LCA also includes a series of lakes formed from past mineral extraction that are now predominantly used for leisure pursuits. The waterways and lakes are typically enclosed by vegetation and woodland areas creating a sense of isolation. The settlement pattern within the northern Colne Valley is relatively sparse, although there is a ribbon of villages along the Grand Union Canal. To the south the valley is more densely populated, with towns such as Uxbridge. The Chiltern Main line runs from east to west through a vegetated corridor across the valley basin to the south of the area. Due to the enclosed nature, low level of vehicular access and sense of isolation, the tranquillity has been assessed as medium. The various lakes that are used for a series of leisure pursuits are maintained to a fair condition.. This LCA is located within green belt and contains a number of conservation areas, namely South Harefield (Widewater Lock Conservation Area) and Denham Country Park LNR (Denham Lock Conservation Area). These factors contribute to make this a regionally valued LCA. Therefore, this area has a high sensitivity to change.
CFA Report – Colne Valley/No7 | Landscape and visual assessment
Colne Valley LCA 9.3.6 The shallow Colne Valley forms Buckinghamshire’s eastern boundary, Hertfordshire’s south western boundary and London’s western edge. The landscape is defined by small arable fields and woodland blocks as well as urban fringe. The River Colne, Grand Union Canal and several lakes are important components of local landscape character, forming the eastern edge of the LCA bordering the Colne River Valley LCA.
Managed and maintained elements within the wider agricultural landscape include Denham Place registered park and garden, ancient woodland and the Buckinghamshire Golf Course. There are also remnants of mineral extraction sites.
The Colne Valley LCA is overall assessed as being in fair condition.
9.3.7 The two main settlements within this LCA are Denham Green and Denham which take up a large proportion of the landscape. Woodland cover is found between the urban fringe of Denham Green and the Colne Valley water bodies, creating a sense of localised seclusion. The Buckingham Golf Course is located to the south of the Chiltern Main Line. Roads and railway lines fragment the landscape in places decreasing both audible and visual tranquillity. Due to these factors, the overall level of tranquillity is considered to be medium. The LCA is located within green belt and includes part of Denham Country Park LNR and Conservation Area. These factors contribute to make this a regionally valued landscape character. Therefore, this area has a high sensitivity to change.
Colne Valley Gravel Pits LCA 9.3.8 The area follows the floodplain of the River Colne from Rickmansworth in the northeast to West Hyde and Harefield in the south. Native hedgerows and trees are generally confined to local roads. Several tracks and PRoW span the floodplain along the edge of the lakes. There are isolated industrial buildings within the floodplain with isolated traditional brick farmsteads on the edge. Within the landscape there are recreational land uses for a wide range of activities and areas of pasture with grazing.
The landscape is relatively well maintained and so the condition of the LCA is assessed as being fair.
9.3.9 The area is dominated by water bodies created from flooded mineral workings, with recreational uses for a wide range of recreational activities. Tree cover forms linear belts which line lakesides, canals and local roads and combine to create a sense of enclosure. It is a relatively peaceful area, on the edge of extensive urbanisation. Due to these factors, the overall level of tranquillity is considered to be medium.
9.3.10 This LCA is located within green belt and includes key elements such as Colne Valley Regional Park resulting in a regionally valued LCA. Therefore, this area is considered to have a high sensitivity to change.
9.3.11 This LCA is located within green belt and includes key elements such as Colne Valley Regional Park resulting in a regionally valued LCA. Therefore, this area has a high sensitivity to change.
Maple Cross Slopes South LCA 9.3.12 The area is located to the west of the Colne Valley floodplain and comprises predominantly well maintained, large open arable fields with minimal hedgerows.
CFA Report – Colne Valley/No7 | Landscape and visual assessment There are woodland areas concentrated on the slopes of narrow dry valleys to the west with prominent urban development on the lower slopes and along the A412 Denham Way/North Orbital Road. The M25 is a dominant feature on the skyline to the west and this, together with the strong urban influences of transport infrastructure and built form, results in a landscape of fair condition and a low level of tranquillity.
The LCA is within green belt and as a result is considered to be of regional value.
Therefore, this area has a medium sensitivity to change.
Chalfont St Peter South LCA 9.3.13 The predominant land use to the south comprises distinct woodland groups, including some ancient woodland, a golf course and the Denham Aerodrome, all of which are situated on a plateau at the edge of the Colne Valley. The area is bordered to the south by the Chiltern Main Line railway embankment. In the north, the M25 traverses the landscape, intersecting a series of dry tributary valleys extending across from the Colne Valley. The M25 also forms the western boundary, close to the urban edge of Chalfont St Peter. The presence of the M25, as well as prominent overhead power line, reduces levels of both audible and visual tranquillity resulting in an overall medium level of tranquillity within the LCA. The varying agricultural landscape is relatively well maintained and is therefore of fair condition. There is also a good network of PRoW across the area. Chalfont St Peter South LCA is within green belt and is of regional value. Therefore, this area has a medium sensitivity to change.
Visual baseline 9.3.14 Descriptions of the identified representative viewpoints are provided, Volume 5:
Appendix LV-001-007 Part 2. A summary description of the distribution and types of receptors most likely to be affected is provided below. The viewpoints are shown on Maps LV-03-024b to LV-03-027a and Maps LV-04-024b to LV-04-027a (Volume 2, CFA7 Map Book). The viewpoints are numbered to identify their locations which are shown on Map Series LV-07 and LV-08 (Volume 5, Landscape and Visual Assessment Map Books). In each case, the middle number (xxx.x.xxx) identifies the type of receptor that is present in this area – 2: Residential, 3: Recreational, 4: Transport.
9.3.15 No protected views have been identified within the study area.
9.3.16 Residential receptors have a high sensitivity to change and are located around Maple Cross and along the perimeter of the settlements of South Harefield and Harefield.
Views are typically rural across the Colne Valley. Residential receptors around Maple Cross also have views of the M25.