7.1.1 Chapter 7: Historic Environment of the PEIR considers the potential effects of the Project on heritage assets including historic buildings and areas, historic landscape character and buried archaeological remains. Such effects could result from a direct physical impact leading to a loss of, or damage to, the heritage asset or harm to the significance of the asset resulting from change within its setting.
7.1.2 Information about existing heritage assets has been acquired from a number of sources, including the Historic Environment Records for West Sussex and Surrey. Contact has also been made with organisations involved in previous archaeological investigations wherever possible, where data are not yet available from Historic Environment Records. Other data sources and baseline surveys have included: the National Heritage List for England; examination of historic maps; LiDAR assessment; aerial photograph assessment; and a detailed walkover survey.
7.1.3 The land within the Project site is predominantly occupied by the operational airport, within which very little remains of the preceding historic landscape. However, there are three designated heritage assets wholly within the Project site boundary (see Figure below). These comprise the Grade II* listed Charlwood Park Farmhouse in the north western part of the Project site, along with Edgeworth House and Wing House, both listed at Grade II, in the eastern part of the Project site.
7.1.5 Charlwood Park Farmhouse is located just outside the current airport perimeter fence and is a timber-framed house of 15th century date, with later additions and amendments. In the 19th century it was the home farm for the Charlwood Park estate; the main house and the park were located further to the east and have been lost to the expanding airport. Wing House and Edgeworth House are separately listed at Grade II but are conjoined and are located in an area of car parking and modern buildings associated with the operational use of the airport, including the adjacent Marriott Hotel of which the historic buildings now form a part. Edgeworth House may be slightly earlier in date (15th or early 16th century), with Wing House being mid-16th century.
7.1.6 One Conservation Area lies partially within the Project site. This is the Church Road Conservation Area on the south western edge of Horley. The eastern part of the Conservation Area comprises a number of historic buildings including the Grade I listed Church of St Bartholomew and the adjacent Grade II listed Ye Olde Six Bells public house.
7.1.7 Within 1 km of the Project site boundary there is a considerable number of designated heritage assets. These include two Scheduled Monuments: an area of former medieval settlement at Tinsley Green to the south east of the airport; and a medieval moated manor house site known as Thunderfield Castle to the north east.
7.1.8 With respect to the construction phase of the Project, good practice measures regarding noise and dust would be adopted and implemented through the Code of Construction Practice. Mitigation against potential impacts to buried archaeological remains would principally comprise avoidance through design or protection by placing material over the archaeological remains such that the impact of construction activities does not extend as far as the remains. The placement of materials may be permanent or may be temporary, with the materials being removed following completion of the construction activities.
7.1.9 A programme of further investigation of the archaeological potential of land within the Project site boundary is planned to take place ahead of the production of the Environmental Statement. The scope of these investigations will be agreed with the archaeological advisors to the relevant planning authority. The results of these investigations would be examined, and any opportunities for mitigation through avoidance or reduction of impact on buried archaeological remains would be identified and considered alongside other factors influencing the design process.
7.1.10 The majority of effects arising during the initial construction phase (2024-2029) would not be significant. Where proposed construction compounds/activities are located on previously developed land (ie the main contractor compound and the eastern part of the airfield satellite compound), archaeological remains are likely to have already been lost or badly damaged by earlier development, thereby limiting the potential for effects to arise.
7.1.11 In the proposed compound locations that are not previously developed, there is the potential for palaeochannels or buried archaeological remains to exist. A programme of archaeological investigation is planned to confirm the date, nature and extent of any archaeological remains, and the results will be reported in the Environmental Statement. The impact on buried archaeological remains as a result of the establishment of contractor compounds on land that has not been previously developed could result in a significance of effect up to major adverse. Appropriate mitigation measures would be incorporated to avoid or reduce damage to the buried archaeological remains. With these measures in place, the significance of effect would reduce to negligible to minor adverse. Where it is not possible to apply any mitigation measures, the effects would be offset by a programme of further archaeological investigation.
7.1.12 Some of the proposed flood compensation areas would involve the lowering of the ground levels. The significance of the effect on buried archaeological remains at Museum Field and land to the east would be up to major adverse and minor adverse (respectively), while an up to major adverse effect is predicted with regard to potential palaeochannels at Car Park X. The effect would be offset by a programme of further archaeological investigation.
7.1.13 The placement of spoil and subsequent construction of the decked car park at Pentagon Field could lead to impacts on buried archaeological remains resulting in a significance of effect up to major adverse. This effect would be offset through a programme of further archaeological investigation.
7.1.14 Environmental mitigation is proposed at parcels of land surrounding Museum Field where planting of trees and hedgerows would be undertaken. Where possible, a programme of archaeological investigation is planned to confirm the date, nature and extent of any archaeological remains, and the results would be reported in the Environmental Statement. The impact on buried archaeological remains as a result of the environmental mitigation could result in a significance of effect up to major adverse. Appropriate mitigation measures would be incorporated into the establishment of the environmental mitigation land surrounding Museum Field to avoid or reduce damage to the buried archaeological remains. With these measures in place, the significance of effect would be negligible to minor adverse. Where it is not possible to apply any mitigation measures, the effects would be offset by a programme of further archaeological investigation.
7.1.15 There may also be up to moderate adverse effects resulting from impacts on potential buried archaeological remains as a result of the construction of the replacement ‘Purple Parking’ at the western end of Crawter’s Field. These effects would be offset by a programme of archaeological investigation.
7.1.16 The relocation of Pond A and the diversion of the River Mole could impact on possible palaeochannels leading to an effect of up to moderate adverse significance. This effect would be offset by a programme of geoarchaeological investigation.
7.1.17 Effects on buried archaeology in other parts of the Project site would not be significant. No significant effects on the setting of heritage assets are likely.
7.1.18 During the period 2030-2032, there could be a major adverse effect on buried archaeological remains as a result of the establishment of the contractor compound at the Longbridge Roundabout. Appropriate mitigation measures would be incorporated into the construction works here to avoid or reduce damage to the buried archaeological remains. With these measures in place, the significance of effect would be minor adverse. Where it is not possible to apply any mitigation measures, the effects would be offset by a programme of further archaeological investigation.
7.1.19 Effects on buried archaeology in other parts of the Project site would not be significant. No significant effects on the setting of heritage assets are likely.
7.1.20 Later in the construction period (2033-2038), the construction of the flood storage area east of Gatwick Stream would lead to the complete loss or substantial damage of buried archaeological remains resulting from the reduction of ground levels. This would result in up to a major adverse effect which would be offset through a programme of further archaeological investigation.
7.1.21 Effects on buried archaeology in other parts of the Project site would not be significant. No significant effects on the setting of heritage assets are likely.
7.1.22 No significant effects on the historic environment would arise following completion of the construction works.
7.1.23 No significant cumulative effects on the historic environment have been identified in the assessment based on the information available to date.