National Character Area Profile: 33. Bowland Fringe and Pendle Hill Source: Natural England

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National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

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1 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Introduction National Character Areas map

As part of Natural England’s responsibilities as set out in the Natural Environment 1 2 3 White Paper , Biodiversity 2020 and the European Landscape Convention , we North are revising profiles for England’s 159 National Character Areas (NCAs). These are East areas that share similar landscape characteristics, and which follow natural lines in the landscape rather than administrative boundaries, making them a good Yorkshire decision-making framework for the natural environment. & The North Humber NCA profiles are guidance documents which can help communities to inform their West decision-making about the places that they live in and care for. The information they contain will support the planning of conservation initiatives at a landscape East scale, inform the delivery of Nature Improvement Areas and encourage broader Midlands partnership working through Local Nature Partnerships. The profiles will also help West Midlands to inform choices about how land is managed and can change. East of England Each profile includes a description of the natural and cultural features that shape our landscapes, how the landscape has changed over time, the current key London drivers for ongoing change, and a broad analysis of each area’s characteristics and ecosystem services. Statements of Environmental Opportunity (SEOs) are South East suggested, which draw on this integrated information. The SEOs offer guidance South West on the critical issues, which could help to achieve sustainable growth and a more secure environmental future.

NCA profiles are working documents which draw on current evidence and knowledge. We will aim to refresh and update them periodically as new 1 The Natural Choice: Securing the Value of Nature, Defra information becomes available to us. (2011; URL: www.official-documents.gov.uk/document/cm80/8082/8082.pdf) 2 Biodiversity 2020: A Strategy for England’s Wildlife and Ecosystem Services, Defra We would like to hear how useful the NCA profiles are to you. You can contact the (2011; URL: www.defra.gov.uk/publications/files/pb13583-biodiversity-strategy-2020-111111.pdf) NCA team by emailing [email protected] 3 European Landscape Convention, Council of Europe (2000; URL: http://conventions.coe.int/Treaty/en/Treaties/Html/176.htm)

2 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Summary Statements of Environmental Opportunity

The Bowland Fringe and Pendle Hill National Character Area (NCA) is a  SEO 1: Protect and enhance the distinctive landscape character of the transitional landscape that wraps around the dramatic upland core of Bowland Fringe and Pendle Hill NCA for its sense of place, historical and the Bowland Fells, underpinned by Carboniferous geology. Over half of cultural heritage, tranquillity, accessibility and recreational opportunities. this NCA, along with the Bowland Fells, makes up the Forest of Bowland Area of Outstanding Natural Beauty. This is a diverse landscape of herb-  SEO 2: Safeguard, manage and enhance the area’s important habitats, rich hay meadows – several of which are nationally and internationally including blanket bog, wet heath, waterbodies and woodland, to provide designated – lush pastures, broadleaved woodland, parkland and benefits for climate change, flood regulation, soil quality and erosion, and waterbodies (including rivers and streams supporting nationally and water quality. internationally protected species). The numerous river valleys and associated woodlands are a major component of the area. To the west,  SEO 3: Manage and enhance the landscape character and biodiversity of this NCA includes part of the Bowland Fells Special Protection Area (SPA), the farmed environment, with its mosaic of pastures and meadows, and designated for its important populations of hen harrier, merlin and lesser strong field patterns defined by drystone walls and hedgerows, to improve black-backed gull. The influence of human habitation and activity, and ecological networks and strengthen landscape character. the area’s long farming history, contribute significantly to its character. In contrast to the predominantly rural feel of the area, this NCA includes  SEO 4: Retain riparian and wetland habitats, and ensure that they are well several relatively urban areas including Clitheroe, Bentham and Longridge. managed and well connected to the high density of waterbodies. Enhance the network to further increase biodiversity, improve its ability to buffer The NCA faces the challenge of managing substantial pressures to pollution, increase flood mitigation and improve water quality. accommodate urban expansion around the major centres of population and recreational destinations, while maintaining and protecting its valuable cultural and biodiversity assets. This, however, also offers increased opportunities, such as through the use of the Pennine Bridleway, to encourage visitors to engage with and enjoy the local environment. A priority for the area is the protection of its rich and distinct landscapes, including the substantial extent of semi- natural woodland, tree-fringed rivers, species-rich hay meadows, and irregular field patterns defined by well-maintained hedgerows and hedgerow trees. To protect the rural quality of the open countryside, it is essential to control and manage the development of the urban fringe and farmsteads to ensure the use of appropriate materials and styles. Click map to enlarge; click again to reduce.

3 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Description4

Physical and functional links to other National The Bowland Fells form a dramatic backdrop to many views within this NCA, and Character Areas the moorland outliers of Beacon Fell, Longridge Fell and Pendle Hill afford long- distance views across the Lancashire plains and valleys towards the Irish Sea. The Bowland Fringe and Pendle Hill National Character Area (NCA) forms a transitional landscape between the dramatic upland core of the Bowland Fells and the flat Lancashire and Amounderness Plain NCA to the west, the Yorkshire Dales NCA to the east and the Lancashire Valleys NCA to the south-east. It lies mainly in Lancashire, but has its eastern edge in the Craven District in North Yorkshire. Over half of this NCA lies within the Forest of Bowland Area of Outstanding Natural Beauty (AONB), which also encompasses the Bowland Fells NCA.

Transport links are concentrated around the lower land, at the fringes of the area, and encircle the Bowland Fells. The M6 and west coast mainline railway line are major north–south links that enclose the area to the west.

The River Lune, in the north of the NCA, has its source in the uplands of the Cumbria High Fells and Howgill Fells, and enters the sea at Morecambe Bay. Its tributaries, the Hindburn, Wenning, Greta and Leck Beck, drain the northern slopes of the Bowland Fells and the south-western part of the Yorkshire Dales. The River Wyre, in the west of the NCA, and its tributaries the Calder and Brock, drain the western and south-western slopes of the Bowland Fells, along with the Conder. The Clear Beck hay meadow southern and eastern parts of the NCA contain the River Ribble (which has its source in the Yorkshire Dales), and its tributaries the River Hodder and Tosside Beck, which drain the southern and eastern slopes of the Bowland Fells. 4 A more detailed description of landscape character is provided in the Forest of Bowland AONB Landscape Character Assessment (2009)

4 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Key characteristics

■ This is an undulating, rolling landscape, with local variation created by ■ There are species-rich hay meadows, including several that are numerous river valleys and by the moorland outliers of Beacon Fell, nationally and internationally designated. Longridge Fell and Pendle Hill. ■ Rough grazing, rushy pasture and traditionally managed meadows ■ The Bowland Fells provide a dramatic backdrop to the north, with at higher elevations are of national importance for breeding extensive views across the river valleys and Lancashire plain below. waders such as redshank, lapwing, curlew and snipe. These are also ■ On the northern edge of the area, drumlins are characteristic, while on important habitats for breeding skylark. the south, strong mounded outcrops or ‘reef knolls’ of limestone form ■ There are numerous rivers of importance for many protected distinct landscape features in the Ribble and Hodder valleys. species, including bullheads, salmon, trout, eels, otters, kingfishers ■ Semi-natural woodland, much of which is ancient, occurs in the main and dippers. There are also many brooks and small reservoirs. valley bottoms, side valleys and ridges, and is dominated by oak, ash ■ There are many archaeological sites, particularly on the moorland and alder. fringes and in valleys where agriculture has been less intensive. ■ Small- to medium-sized fields are defined by hedgerows with mature ■ A network of winding, hedge-lined lanes connect small, often hedgerow trees. Drystone walls are also common in some areas. Metal linear, villages, hamlets and scattered farmsteads, mostly in local railings around estate boundaries and highway corners and junctions stone. Traditional stone barns are commonplace on higher ground, are characteristic of the southern and western edges of the NCA. and are of stone with slate or stone flag roofs. ■ Land use is mainly permanent, improved pasture for livestock and dairy ■ Isolated country houses set in formal parkland are typical of the farming. area, and may be enclosed by belts of woodland and estate fencing. ■ To the west, this NCA includes part of the Bowland Fells Special ■ The relatively urban areas of Clitheroe, Bentham and Longridge Protection Area (SPA), designated for its important populations of hen provide a contrast to the rural feel of the area. harrier, merlin and lesser black-backed gull.

5 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Bowland Fringe and Pendle Hill today This is a diverse landscape of undulating pasture, broadleaved woodland, parkland and waterbodies, including oxbow lakes, reservoirs, disused gravel pits and field ponds. Fields are small to medium-sized, and are enclosed by Bowland Fringe and Pendle Hill is a transitional landscape which wraps hedgerows with large mature hedgerow trees. Improved pastureland defined around the dramatic upland core of the Bowland Fells. It extends from the by well-maintained hedgerows is characteristic of the agricultural land in the Lune Valley in the north, around the slopes of the Bowland massif, before fringes, which supports both dairy and livestock farming. Over half of this merging imperceptibly eastwards into the landscape of the Ribble Valley. The NCA is within the Forest of Bowland AONB. eastern boundary links with the Yorkshire Dales, while the Lancashire Valleys lie to the south. To the south of Bowland, the moorland outliers of Pendle Hill, Beacon Fell and Longridge Fell, found on Carboniferous Limestone knoll reefs, enclose the Ribble Valley and reinforce its affinity with the Forest of Bowland. The combination of topography, tree cover and field enclosure creates a sense of intimacy which contrasts with the vast expanse of the coastal plain and the exposed moorland heights of the Bowland Fells. Similarly, the herb- rich limestone knoll reefs located around Clitheroe and Chatburn are distinctive and provide unusual relief in a pastoral landscape, as well as a rocky promontory on which Clitheroe Castle is situated.

To the north of Bowland is the Lune Valley, which separates the Fringe from Morecambe Bay. It has a pastoral character, with a meandering river and fields enclosed by hedgerows containing mature hedgerow trees. Deciduous woodland, including some areas of ancient woodland, is concentrated on valley sides, and is most prominent in the Roeburn, Wenning, Greta and Hindburn valleys.

While lying just beyond the boundary of the NCA, the major conurbations of Lancaster to the west, Preston to the south-east and Settle to the east, all exert an influence over the area, through visits for recreational activities, tourism and commerce. Lune Valley view, the Bowland Fells can be seen in the background

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Small to medium-sized hay meadows and permanent pasture fields are dominated by oak, ash and birch, with extensive amounts of wych elm and defined by stone walls immediately adjacent to the Bowland Fells, but wild gean, especially along the Ribble, with alder and willow beside the these become hedgerows within valley bottoms and in areas around Brock, Wyre and Calder. The woodlands on the northernmost side of the settlements. Mature oak, ash and alder trees are common components of Fells are particularly important for their rich assemblage of mosses and hedgerows. Pignut, yellow rattle, great burnet, oxeye daisy and lady’s mantle lichens. Pied and spotted flycatchers, redstart, tree pipit, tawny owl, great can all be found in the species-rich hay meadows. At higher elevations the spotted woodpecker and sparrow hawk are all characteristic bird species improved pastures give way to areas of rough grazing and field patterns associated with these woodlands. become more regular, with stone walls predominating. Here, wet rushy pastures are of particular importance for breeding waders such as lapwing, The settlement pattern is of small stone villages, hamlets and farmsteads. snipe, curlew, redshank and oystercatchers. The isolated country houses set in formal parkland, such as Browsholme and Quernmore, are a typical feature of the landscape. These managed Numerous rivers and watercourses provide habitats for salmon, brown and estates are enclosed by belts of woodland and estate fencing, and typically sea trout, eels, lampray and bullheads, as well as birds such as kingfishers, consist of open grassland with ponds and lakes, scattered trees of oak, ash, dippers, grey wagtail, common sandpiper and oystercatchers. Otters are sycamore and lime, enclosed by blocks of secondary woodland. Farms tend also present along rivers and streams throughout the area. The rivers make to be larger than those in the Bowland Fells, with better-quality land a significant contribution to the area, as does the Lancaster Canal, which supporting large dairy herds. Farms generally consist of a core of farm supports an interesting array of locally rare aquatic plants such as flowering buildings and some conspicuous modern outbuildings. rush, greater spearwort, white water lily and various pond weeds. A number of reservoirs and disused gravel pits along the Wyre Valley are also important The road network is typified by a complex system of narrow lanes, with few as habitat for breeding great crested grebe and wintering wildfowl, while the high direct routes between settlements. The railway, canal and M6 form the major density of field ponds between Preston and Garstang provide an important north–south links in Lancashire, and are confined to a narrow corridor that habitat for aquatic plants, freshwater invertebrates and amphibians. defines the western boundary. The Pennine Bridleway crosses the eastern corner of this NCA. Extensive areas of predominantly ancient, semi-natural woodland are concentrated on the ridges, slopes and valley sides of the many rivers present This is an intimate, tamed landscape in contrast to the wild, exposed throughout the area. There are areas of ancient woodland along the Hodder moorland of the Bowland Fells. The combination of well-maintained between Whitewell and Hurst Green, as well as along the Brock and Calder, hedgerows and hedgerow trees, areas of parkland and well-grazed pasture, and between Dolphinholme and Abbeystead. Woodlands here are gives this area a managed character.

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The landscape through time

This is a transitional zone between the coastal plain, with its unconsolidated glacial meltwater. One such complex, in the Ribble and Hodder valleys at glacial deposits, and the high fells of Bowland, formed by the strong Stonyhurst and Hurst Green, imparts a special quality of small wooded knolls sandstone of the Millstone Grit. The transition from plain to fell landscape to the local landscape. To the east of Gisburn, a tract of drumlins forms a is rapid, and reflects the existence of a substantial boundary fault separating characteristic landscape. the soft Permo-Triassic rocks from the harder Carboniferous rocks. The transition is softened by the presence of thicker glacial deposits around the edge of the upland area, and by the valley features where Bowland’s upland streams flow out of the hills onto the plain.

In the south, where the Brock Valley crosses the area, the coarse-grained sandstones of the Millstone Grit of Bowland give way to the softer calcareous mudstones, with limestone beds, of the Carboniferous Limestone. This accounts for the less dramatic change between the Fringe and Fells landscapes. Surface drift features also become more important as the Fringe merges imperceptibly south-eastwards into the landscape of the Ribble Valley. The Ribble and Hodder drain the southern flanks of the Bowland Fells. Within the valleys, strong mounded outcrops or ‘reef knolls’ form distinctive landscape features that give the area its special character.

The Lune Valley area is gently sloping and undulating, and is contained by steep scarp slopes with the river as the central feature. The Lune’s many tributaries commonly arise from deep erosion scars, or cloughs, cut into the steep scarp slopes of the surrounding moorland upland. The solid rocks are overlain by a complex of glacial deposits, mainly comprising thick tills but also with extensive areas of hummocky sand and gravel deposited from

Little Bowland Knoll Reefs, Tunstall

8 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

The Lune Valley has been used as a communication route since the Roman The 19th-century (and earlier) settlement pattern, still largely unaltered, tends period – and even earlier. It formed a principal route for the Anglian invasion towards nucleated villages in the river valleys to the north and south-east of Lancashire from the east from 570 AD, and for Norse settlers from the Isle of of the Bowland Fells, and more heavily dispersed patterns of isolated Man, Scotland and Northern Ireland from the early 10th century. The lush farmsteads and small farming hamlets across the west and south-west. pasture and arable land in the Lune Valley has long supported prosperous Vaccaries (cattle stock farms), founded in the 12th and 13th centuries, had farms – from the medieval period and earlier – and this is reflected in the a large impact on the settlement pattern, especially in the Lune Valley, number of large farms and country estates that are scattered along the valley developing into farmsteads as they were let out by landowners from the 14th sides. The Ribble Valley formed an important Roman communication route to century. The settlement pattern of small villages with isolated houses and York, and some evidence of Roman roads can still be found. farms dotted around the winding country lanes dates from the medieval period. Population increases in the 12th and 13th centuries expanded the pattern of settlement through the assarting of former woodland, to produce a small-scale and intimate landscape of scattered farms linked by winding roads and irregular fields, still very evident in the Lune and Ribble valleys. From the 15th century, many small farms were created from vaccaries, and large areas of the adjacent hunting lands of ancient Forest Law were being sold or leased for grazing. Hunting status was, however, retained through the creation of private deer parks within the country estates of the nobility, which have left traces in the boundary and woodland patterns of the area – notably around Pendle Hill and along the upper reaches of the Hodder.

The field pattern around settlements and on valley bottoms is generally irregular, and small to medium in scale, which indicates medieval to 17th-century enclosure from woodland and moor, and also from medieval strip fields. Areas of common land at higher elevations have a more regular field pattern, following late 18th- and 19th-century Parliamentary enclosure. A particular feature of this area is the number of large country houses and halls set in parkland, such as Ellel Grange, Waddow Hall, Bolton Park and Leagram Hall, as well as country Large country houses and halls set in parkland, such as Leagram Hall, are a particular estates, such as Abbeystead, which have developed from the medieval period. feature of the area

9 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

In addition to these country houses and halls, there is a distinctive architectural legacy of stone-built farmsteads, houses and settlements, mostly dating from rebuilding in the 18th and 19th centuries.

Isolated stone villages tend to be nestled into the escarpments and are commonly characterised by distinctive becks, greens and mills – each with its own unique charm. Many of the smaller villages and hamlets are linear in character and commonly take the form of terraced stone cottages along the main road. Farmsteads tend to consist of a core of vernacular stone buildings, many dating from the 17th century, with either stone-flagged or slate roofs. On higher ground, traditional stone field barns are commonplace.

The textile industry developed from the 15th century, and farmsteads and settlements retain significant evidence of loom shops, with large windows dating from the 17th century. Industry is also represented by some small mill settlements in the Calder Vale, Oakenclough, Dolphinholme and Galgate (terraced cottages associated with mills), and by lead-mining remains and derelict lime kilns along the Ribble Valley. Settlement expansion dating from the 19th and 20thcenturies is generally restricted to the south and south-east (Clitheroe and Longridge). Modern development around village fringes gives a suburban character, with a mix of building materials and styles.

Barn at Overhouses, Ingleborough can be seen in the background in the adjaceent Yorkshire Dales NCA

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Ecosystem services Regulating services (water purification, air quality maintenance and climate regulation) The Bowland Fringe and Pendle Hill NCA provides a wide range of benefits to ■ Regulating climate change: In this NCA, soil carbon levels are generally society. Each is derived from the attributes and processes (both natural and low (between 0 per cent and 5 per cent), reflecting the mineral soils that cultural features) within the area. These benefits are known collectively as cover 72 per cent of the area. Small areas of higher soil carbon adjoin ‘ecosystem services’. The predominant services are summarised below. Further the peaty upland area of the Bowland Fells. These soils store significant information on ecosystem services provided in the Bowland Fringe and Pendle volumes of carbon dioxide and other greenhouse gases. Degraded peat Hill NCA is contained in the ‘Analysis’ section of this document. bogs release stored carbon dioxide and other greenhouse gases into the atmosphere and through water run-off. Sustainable management Provisioning services (food, fibre and water supply) of blanket bog and other moorland habitats provides an opportunity ■ Food provision: The Bowland Fringe and Pendle Hill area is important for to safeguard existing stores of greenhouse gases while sequestering rearing livestock. Many traditional farming practices are still employed increased volumes from the atmosphere. Soil carbon levels will also be here, providing a food resource from the sustainable rearing of sheep high under areas of woodland, and carbon storage and sequestering is and cattle. Locally sourced food also plays an increasingly important role provided by the woodland itself. in supporting tourism in the area, and in the process helps to encourage Bowland’s green economy. ■ Regulating soil erosion: Almost a third of this NCA has a high risk of soil erosion. The slowly permeable, wet, very acid upland soils with a peaty ■ Timber provision: Some 7 per cent of the area is woodland, and a surface often found on the moorland plateau tops are at risk of gullying quarter of this is coniferous plantation. Several large blocks of conifer or hagging (and of losing particulate organic matter) where the surface plantation are present, mainly in the south and north-west, some of vegetation is damaged, highly modified or lost. Drainage of these soils which are managed for productive timber. There are opportunities for may also result in increased oxidation of carbon and soil wastage. Erosion local woodland products, including wood fuel, from both the conifer and is equally prevalent on the very acid, loamy upland soils with a wet peaty broadleaved under-managed woodlands. surface often found on steep slopes, where a combination of rapid run-off and easily damaged peat layers results in soil erosion. The freely-draining, ■ Water availability: Principal surface water resources within the NCA are slightly acid, loamy soils and the lighter-textured (less clayey) variants of the catchments of the rivers Lune, Wyre and Ribble. Abstraction is mainly freely-draining, lime-rich, loamy soils can erode easily on steep slopes – for public water supply, industry, aquaculture, energy generation and especially where vegetation is removed, soil is compacted or organic matter topping up the Lancaster Canal. levels are low after continuous cultivation. There is also potential for wind erosion on some coarse-textured, cultivated variants of the former soil type.

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■ Regulating soil quality: Over 70 per cent of this NCA may be subject to Cultural services (inspiration, education and wellbeing) soil quality issues. The slowly permeable, seasonally wet, acid loamy and ■ Sense of place/inspiration: This NCA forms part of the Forest of Bowland clayey soils may suffer compaction and/or capping, as they are easily AONB, designated in 1964 because the landscape was thought to be damaged when wet. In turn, this may lead to increasingly poor water of national importance and worthy of protection. A sense of place is infiltration and diffuse pollution as a result of surface water run-off. provided by the undulating, rolling landscape that skirts the edge of the Conversely, the slowly permeable, wet, very acid upland soils with a peaty Bowland Fells, forming a dramatic backdrop. There are sharp variations surface are at risk of a loss of organic matter through drought induced by in the local landscape resulting from the river valleys and numerous a changing climate and soil erosion. small hills. There are also strong contrasts between the area’s traditional farmsteads and settlements (which include evidence of textile working), ■ Regulating water quality: Ecological river water quality is moderate or a small number of industrial settlements, and country houses usually poor in much of the River Lune catchment, although the rivers Wenning set within extensive, semi-natural woodland and well-maintained and Greta have good water quality. Langthwaite Reservoir is of moderate formal parkland. The landscape is intensively managed and largely of ecological quality. The River Conder is of moderate quality, as is the permanent, improved pasture for dairy and livestock farming, with small River Calder, while the remainder of the Wyre is of good quality. The to medium-sized herb-rich hay meadows defined by well-maintained River Ribble downstream of Gisburn, including several of its tributaries, hedgerows with mature hedgerow trees, and rough grazing at higher are of moderate quality, and most of the remainder of the Ribble levels. Woodland forms a significant landscape element within the area. catchment within this NCA has good water quality. The chemical status of groundwater is poor in the north and west of the NCA, but good in both ■ Sense of history: The enclosed landscape – with its legacy of farmsteads, the south and east. medieval to post-medieval irregular fields, and regular enclosures from moorland of the 19th century – is testament to settlement and land use ■ Regulating water flow (flooding): This NCA envelops the higher land mass from the medieval period onwards. Apart from the extensive evidence of that forms the Bowland Fells, and contains the middle part of the rivers medieval settlement and land use, a much earlier development from the that drain that upland area, with its steep topography and narrow flood pre-Roman period is evident in the many archaeological sites – particularly plains. This, combined with waterlogged moorland soils and high rainfall, on the moorland fringes and in valleys, where agriculture has been less produces watercourses that respond rapidly to rainfall, increasing fluvial intensive, as well as in corridors like the Ribble and Lune valleys, which flood risk. were important routes from the Roman period onwards (small motte- and-bailey castles being found in the latter). A small number of industrial terraced settlements are characteristic of the Calder Vale, while lead-mining remains and derelict lime kilns are found in the Ribble Valley.

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■ Tranquillity: This NCA is important for the tranquillity it provides: 76 per cent ■ Recreation: This is supported by the Pennine Bridleway (19 km of which of the area was classified as ‘undisturbed’ by the Campaign to Protect Rural lies in this NCA). There are 1,537 km of rights of way, with a density of England in 2007, although this is a significant decrease from the figure of 2 km per km². Open access land covers 6.4 per cent of the NCA (4,728 92 per cent recorded in the 1960s. The lowest areas of tranquillity lie along ha). Cycling continues to be popular, with increasing opportunities for the major road corridors such as the M6, A65 and A59, as well as around the off-roading along bridleways. Road cycling is also popular, especially towns of Clitheroe and Longridge. A sense of tranquillity is likely to be most on the designated ‘quiet lanes’ around Chipping and Downham, and as associated with the wooded river valleys, as well as with the parklands, part of the more challenging Tour of Pendle race. There are opportunities picturesque villages and hamlets on undulating lowland farmland, and for horseriding along the network of greenways and bridleways. Other with some small-scale and intimate landscapes in the Lune and Ribble popular activities include birdwatching, fishing, gliding and shooting. In valleys. These areas help to deliver health and wellbeing benefits to all of addition, there is a developing network of tramper trails that are suitable their visitors: the natural environment provides areas of relative tranquillity for people using off-road mobility scooters and pushchairs. The ability to and sensory experience for meditation and relaxation, which in turn has a access green spaces has been demonstrated to encourage contact with calming and restorative effect and helps to improve mental wellbeing. nature and participation in physical activity – both of which encourage the adoption of other healthy lifestyle choices such as social engagement and consumption of healthy foods.

■ Biodiversity: Biodiversity Action Plan (BAP) priority habitats cover 6,000 ha (8 per cent) of the NCA and include 1,700 ha of upland heathland and smaller areas of a variety of woodland, grassland and riverine priority habitats. The NCA contains two Special Areas of Conservation (SAC) and one Special Protection Area (SPA), and 2,300 ha (3 per cent of the NCA) are nationally designated as a Site of Special Scientific Interest (SSSI).

■ Geodiversity: There are currently six nationally designated geological sites within the NCA. These consist mainly of river sections and exposures, along with one of the best examples of knoll reefs in northern England, making up the Clitheroe Knoll Reefs SSSI. The 25 Local Geological Sites include examples of river channels and sections, glacial and fluvio-glacial View across Clitheroe landforms, disused quarries and ancient coal workings.

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Statements of Environmental Opportunity

SEO 1: Protect and enhance the distinctive landscape character of the Bowland Fringe and Pendle Hill NCA for its sense of place, historical and cultural heritage, tranquillity, accessibility and recreational opportunities.

For example, by: ■ Encouraging the conservation and restoration of the managed ■ Promoting enjoyment, awareness and understanding of the NCA, landscapes of isolated country houses – in particular the woodland belts particularly around less well-known sites and features, to relieve pressure and estate fencing. on busier destinations (especially Beacon Fell, Brockbottom, Jeffrey ■ Conserving and managing traditional stone farm buildings and artefacts, Hill and Kemple End), in order to maintain existing levels of tranquillity, ensuring the use of local styles and materials in order to maintain the remoteness and landscape character. historic and rural character of the countryside and built environment of ■ Sympathetically managing recreational sites to enhance visitors’ rural settlements. experience and their enjoyment of contact with the natural environment, ■ Conserving significant archaeological sites as part of the evidence for the while managing erosion and traffic, to benefit landscape and wildlife. area’s development from the medieval period and earlier. ■ Using the Pennine Bridleway and the network of paths to gain access to, ■ Managing development (especially around the fringes of the NCA), in reveal and interpret the area’s rich history. order to maintain the rural character of the landscape, tranquillity and sense of remoteness. Protecting the area from development on ridgelines and hilltops, to maintain the predominantly open character of the landscape.

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SEO 2: Safeguard, manage and enhance the area’s important habitats, including blanket bog, wet heath, waterbodies and woodland, to provide benefits for climate change, flood regulation, soil quality and erosion, and water quality.

For example, by: ■ Ensuring that all areas of blanket bog are under good environmental ■ Protecting, restoring and managing the semi-natural woodland. Much management. Ensuring good vegetative cover and reducing high rates of this is ancient, occuring in the main valley bottoms, side valleys and of run-off by restoring the hydrology and ecology of peat habitats. Re- ridges, and is dominated by oak, ash and alder. vegetate bare peat. ■ Restructuring conifer plantations to increase broadleaved component ■ Managing the moorland fringe in order to maintain the mosaic of and to soften edges. landscape features of the rolling upland farmland, including hay ■ Exploring opportunities to plant new native woodlands appropriate to meadows and grasslands used by breeding waders. the area’s character. Ensuring that woodland expansion avoids peat, and ■ Encouraging sustainable grazing regimes to avoid poaching of soils and avoids impacting on other sites of biodiversity or historic value. to aid water infiltration. ■ Exploring opportunities to get existing woodland into management for local woodland products and wood fuel supply.

SEO 3: Manage and enhance the landscape character and biodiversity of the farmed environment with its mosaic of pastures and meadows, and strong field patterns defined by drystone walls and hedgerows, to improve ecological networks and strengthen landscape character.

For example, by: ■ Conserving and restoring semi-natural and species-rich hay meadows, ■ Managing nutrients on farmsteads and improved pastures, targeting particularly in the flood plain and farmed landscapes, to counter the applications to maximise uptake and minimise run-off. effects of intensification. ■ Conserving and restoring the field boundaries defined by hedgerows, ■ Managing pastures in ways that build up organic matter and avoid drystone walls, boundary trees and metal estate railings, in order to compaction. reduce the enlargement of fields, replacement with stock fencing and ■ Avoiding carrying out mechanised activities (such as trafficking) that will lack of management. cause compaction of soils, especially in wet conditions. ■ Addressing the restoration and management of the characteristic field ponds north of Preston.

15 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

SEO 4: Retain riparian and wetland habitats, and ensure that they are well managed and well connected to the high density of waterbodies. Enhance the network to further increase biodiversity, improve its ability to buffer pollution, increase flood mitigation and improve water quality.

For example, by: ■ Conserving and managing the numerous watercourses and bodies, ■ Seeking opportunities that will allow rivers to follow their natural course including the rivers Ribble, Hodder, Calder, Wyre and Lune, as well as a and re-engage with their flood plain. number of reservoirs and field ponds north of Preston. ■ Encouraging the management and restoration of riparian woodland ■ Restoring and managing field ponds and wetlands throughout the valley for protection against river bank erosion and for their value as habitat flood plain and undulating lowland farmland. Using quarry restoration as corridors. an opportunity for wetland and other habitat creation. ■ Protecting water quality through the use of extensive grazing and ■ Managing blanket bog and rushy upland pasture, and conserving it from permanent grassland creation adjacent to watercourses to reduce run-off. degradation, which results in increased run-off to streams and rivers, ■ Managing nutrients on farmsteads and improved pastures, targeting river bank erosion and deterioration in downstream water quality. applications to maximise uptake and minimise run-off.

Additional opportunities

1. Protect the strong relationship between landscape and the underlying geology, the land use it supports and its significance to the cultural identity of the area.

For example, by: ■ Maintaining key views of landform and geological features, and using ■ Keeping important geological exposures – such as quarry faces, semi-natural land cover to enhance and support biodiversity (but not cuttings, outcrops and stream sections – visible and, where appropriate, obscuring landform features). accessible.

16 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Supporting document 1: Key facts and data Area of Bowland Fringe and Pendle Hill National Character Area (NCA): 74,090 ha 1. Landscape and nature conservation designations 1.1 Designated nature conservation sites The NCA includes the following statutory nature conservation designations: Some 52 per cent of the NCA (38,175 ha) falls within the Forest of Bowland Area of Area % of Outstanding Natural Beauty (AONB). The Forest of Bowland AONB Management Tier Designation Name (ha) NCA Plan provides a policy framework and identifies a 5-year programme of actions (April 2009 - March 2014) to help guide the work of the AONB partnership International n/a n/a 0 0 organisations towards achieving the purpose of this plan; to conserve and European Special Protection Bowland Fells SPA 1,453 2 enhance the natural and cultural beauty of the Forest of Bowland landscape. The Area (SPA) management plan can be downloaded at: Special Area of Calf Hill and Crag 41 <1 Conservation (SAC) Woods SAC; North http://www.forestofbowland.com/cons_managementplan Pennine Dales Meadows SAC Less than 1 per cent of the NCA (181 ha) falls within the Yorkshire Dales National National National Nature n/a 0 0 Park. Please see NCA 21 Yorkshire Dales for further details. Reserve (NNR) Source: Natural England (2011) Site of Special A total of 28 sites 2,267 3 Scientific Interest wholly or partly (SSSI) within the NCA Source: Natural England (2011)

Please Note: (i) Designated areas may overlap (ii) all figures are cut to Mean High Water Line, designations that span coastal areas/views below this line will not be included.

Within the NCA a total of 2,267 ha is under European or national designation.

The Bowland Fells SPA and Bowland Fells SSSI comprise the same area, and 9 per cent of this falls within the NCA.

17 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

The North Pennine Dales Meadows SAC comprises 3 SSSI meadows one of ■ Details of SSSI condition can be searched at: which (Langcliff Cross Meadow SSSI) is wholly within the NCA, Part of Bell http://www.sssi.naturalengland.org.uk/Special/sssi/reportIndex.cfm Sykes Meadows SSSI is also within the NCA.

Calf Hill & Crag Woods SSSI and SAC comprise the same area and all but the 2. Landform, geology and soils southern tip of Calf Hill Wood is within the NCA. 2.1 Elevation There are 347 Local sites in Bowland Fringe and Pendle Hill NCA covering The NCA is a transitional landscape which wraps around the upland core of the 5,139 ha, which comprises 7 per cent of the NCA. Bowland Fells. Elevation ranges within this NCA from 9 m above sea level to 577 m. . Source: Natural England (2011) Source: Natural England 2010

■ Details of individual Sites of Special Scientific Interest can be searched at: 2.2 Landform and process http://www.sssi.naturalengland.org.uk/Special/sssi/search.cfm This is an undulating and rolling landscape with local variation created by ■ Details of Local Nature Reserves (LNR) can be searched at: numerous river valleys and by the moorland outliers of Beacon Fell (266 m), http://www.lnr.naturalengland.org.uk/Special/lnr/lnr_search.asp Longridge Fell (350 m) and Pendle Hill (577 m) on the south side of the area. ■ Maps showing locations of Statutory sites can be found at: Source: Bowland Fringe and Pendle Hill Countryside Character Area description http://magic.defra.gov.uk/website/magic/ – select ‘Rural Designations Statutory’ 2.3 Bedrock geology The transition from plain to fell landscape is rapid and reflects the existence of 1.1.1 Condition of designated sites a substantial boundary fault which separates the soft Permo-Triassic rocks from the harder Carboniferous rocks. In the south where the Brock Valley crosses the Percentage of NCA area, the coarse-grained sandstones of the Millstone Grit of Bowland give way SSSI Condition Category Area (ha) SSSI Resource to the softer calcareous mudstones, with limestone beds of the Carboniferous Unfavourable declining 15 <1 Limestone. The broad Ribble and Hodder Valleys broadly pick out the less resistant mudstones and limestones from the Millstone Grit rocks which Favourable 591 26 form the fells. Within the valleys, strong moundy outcrops of reef knolls form Unfavourable no change 358 16 distinctive landscape features, which give the area its special character. Unfavourable recovering 1,298 57 Source: Bowland Fringe & Pendle Hill Countryside Character Area description Source: Natural England (March 2011)

18 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

2.4 Superficial deposits 2.6 Soils and Agricultural Land Classification The rapid transition from plain to fell landscape is softened by the presence Poorer quality soils (Grade 4) occur in the higher areas around the Bowland Fells of thicker glacial deposits around the edge of the upland area. The mouths of fringe and on the east side of the NCA. The better quality (Grade 3) soils occur the valleys are commonly filled by broad, flat alluvial fans. Ribbons of alluvial around the north south-west and south. There are 8 main soilscape types in this sand, gravel and silt follow the courses of these streams. The solid rocks area: Slowly permeable seasonally wet acid loamy and clayey soils, covering 57 per are overlain by a complex of glacial deposits comprising mainly thick tills cent of the NCA. Slowly permeable wet very acid upland soils with a peaty surface but with extensive areas of moundy sand and gravel deposited from glacial (15 per cent); Slowly permeable seasonally wet slightly acid but base-rich loamy meltwater. Distinctive drumlins form a characteristic landscape within the and clayey soils (6 per cent); Very acid loamy upland soils with a wet peaty surface river valleys to the north and east. (6 per cent); Freely draining slightly acid loamy soils (5 per cent); Freely draining Source: Bowland Fringe & Pendle Hill Countryside Character Area description floodplain soils (3 per cent); Loamy and clayey floodplain soils with naturally high groundwater (3 per cent) and Freely draining lime-rich loamy soils (1 per cent). 2.5 Designated geological sites Source: Natural England 2010

Tier Designation Number The main grades of agricultural land in the NCA are broken down as follows (as a proportion of total land area): National Geological Site of Special Scientific Interest (SSSI) 6 National Mixed Interest SSSIs 0 Grade Area (ha) % of NCA Local Local Geological Sites 25 Grade 1 0 0 Grade 2 39 <1 Source: Natural England (2011) Grade 3 27,540 37 *Local sites are non statutory designations Grade 4 36,019 49 ■ Details of individual Sites of Special Scientific Interest can be searched at: Grade 5 9,773 13 http://www.sssi.naturalengland.org.uk/Special/sssi/search.cfm Non-agricultural 342 <1 Urban 378 <1 Source: Natural England (2010)

Maps showing locations of Statutory sites can be found at: http://magic.defra.gov.uk/website/magic/ – select ‘Landscape’ (shows ALC classification and 27 types of soils).

19 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

3. Key water bodies and catchments The northern part of the NCA contains the River Lune and its tributaries the River Hindburn (which drains the northern slopes of the Bowland Fells NCA), the River Wenning (which drains northern slopes of the Bowland Fells NCA and south- 3.1 Major rivers/canals west parts of the Yorkshire Dales NCA), and the River Greta and Leck Beck (which The following major rivers/canals (by length) have been identified in this NCA. drain the south-west parts of the Yorkshire Dales NCA).

■ Great Stour 9 km The River Lune itself has its source further north in the uplands of the Cumbria ■ Little Stour 10 km High Fells and Howgill Fells NCAs. ■ River Ribble 40 km ■ River Wenning 21 km The western part of the NCA contains rivers which drain the western and south ■ River Hodder 20 km west slopes of the Bowland Fells - the River Wyre and its tributaries the rivers ■ River Lune 15 km Calder and Brock as well as the River Conder which flows directly to the Irish Sea. ■ River Wyre 13 km ■ River Brock 11 km The southern and eastern parts of the NCA contain the River Ribble, which has its ■ River Greta 11 km source in the Yorkshire Dales NCA, and its tributaries the River Hodder and Tosside ■ River Hindburn 11 km Beck which drain the southern and eastern slopes of the Bowland Fells NCA. ■ Tosside Beck 11 km ■ River Conder 9 km 3.2 Water quality ■ River Calder 7 km The total area of Nitrate Vulnerable Zone is 43,541 ha, 59 per cent of the NCA. Leck Beck 3 km ■ Source: Natural England (2010) ■ Sabden Brook <1 km Source: Natural England (2010) 3.3 Water Framework Directive Maps are available from the Environment Agency showing current and projected Please Note: other significant rivers (by volume) may also occur. These are not listed where the length within the NCA is short. future status of water bodies at:

Some 13 rivers flow through the NCA totalling 173 km. The NCA surrounds the http://maps.environment-agency.gov.uk/wiyby/wiybyController?ep=maptopic Bowland Fells and contains the middle part of rivers that drain the upland area s&lang=_e with its steep topography and narrow floodplains.

20 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

4. Trees and woodlands Area and proportion of different woodland types in the NCA (over 2 ha): Woodland type Area (ha) % of NCA 4.1 Total woodland cover Broadleaved 3,174 4 The NCA contains 5,060 ha of woodland (7 per cent of the total area), of which 1,165 ha is ancient woodland. Coniferous 1,222 2 Source: Forestry Commission (2011) and Natural England (2010) Mixed 411 1 Other 253 <1 4.2 Distribution and size of woodland and trees in the landscape Source: Forestry Commission (2011) Extensive areas of predominantly ancient semi-natural woodland are concentrated on the ridges, slopes and valley sides of the many rivers present throughout Area and proportion of Ancient Woodland and Planted Ancient Woodland within the area. Woodlands here are dominated by oak, ash and birch with extensive the NCA: amounts of wych elm and wild gean, especially along the Ribble with alder and willow beside the Brock, Wyre and Calder. Areas of semi-natural woodland are commonly associated with managed estates and parkland. Several large blocks of Type Area (ha) % of NCA conifer plantation are present, mainly in the south and north-west. Ancient semi-natural woodland 903 1 Source: Source Bowland Fringe & Pendle Hill Countryside Character Area description Planted Ancient Woodland (PAWS) 262 <1 Source: Natural England (2004) 4.3 Woodland types A statistical breakdown of the area and type of woodland found across the NCA is detailed below. 5. Boundary features and patterns

5.1 Boundary features Medium to small-scale fields are defined by hedgerows with mature hedgerow trees, growth of which is particularly vigorous in the north. Dry stone walls are also common in some areas. Metal railings around estate boundaries are characteristic of the southern and western edges of the NCA. Source: Bowland Fringe & Pendle Hill Countryside Character Area description; Countryside Quality Counts (2003)

21 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

5.2 Field patterns 6.2 Farm size Principally an area of intricate small-medium scale fields reflecting a long process There is a fairly even distribution in farm size with, in 2009, 184 (17 per cent) <5 of piecemeal colonisation and assortment. Ancient (pre 1600) enclosure has ha, 207 (19 per cent), 5 to 20 ha, 234 (22 per cent) 20 to 50 ha, 246 (23 per cent) 50 widespread survival, but is particularly concentrated to the south. Post medieval to 100 ha and 216 (20 per cent) >100 ha. Between 2000 and 2009 the number of (1600-1850) enclosure patterns, similarly irregular, are the dominant field pattern commercial holdings decreased overall by 7 per cent from 1,172 to 1,087. This in the area. Much of the higher common land and the lower fellsides especially to decrease was across all size bands with the exception of the smallest (<5 ha) and the west of the Bowland fells remained unenclosed until taken into large rectilinear largest (>100 ha) holdings both of which showed a slight increase. (Note: these grazing enclosures under Parliamentary Acts in the 18th and 19th centuries. figures do not include the access that many farms have to common grazing on the Source: English Heritage Historic Profiles; Countryside Character Area description; moors). Countryside Quality Counts (2003) Source: Agricultural Census, DEFRA (2010)

6. Agriculture 6.3 Farm ownership 2009: Total farm area = 66,610 ha; owned land = 36,723 ha 2000: Total farm area = 65,786 ha; owned land = 39,016 ha. The following data has been taken from the Agricultural Census linked to this NCA. In 2009 55 per cent of the total farmed area was owner occupied. Between 2000 and 2009 there has been an increase in the total farmed area of 824 ha (1 per 6.1 Farm type cent) although there has been a slight decrease in the number of holders from The NCA is characteristically a livestock grazing area. In 2009 there were 400 1,860 to 1,657. commercial livestock grazing holdings in the LFA (37 per cent) and 159 in the Source: Agricultural Census, DEFRA (2010) lowlands (15 per cent). There were also 254 dairy holdings (23 per cent), 22 specialist poultry holdings (2 per cent), 10 horticultural holdings (1 per cent) 6.4 Land use and 7 specialist pig holdings (<1 per cent). Survey data from 2000 to 2009 shows The predominant land use in this NCA is grass and uncropped land mainly for a 29 per cent increase in the number of grazing farms in the LFA whilst grazing sheep and some cattle and pig rearing. farms in the lowlands have decreased by 7 per cent and dairy farms have Source: Agricultural Census, DEFRA (2010) decreased by 41 per cent. Source: Agricultural Census, DEFRA (2010)

22 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

6.5 Livestock numbers give way to areas of rough grazing and field patterns become more regular, Sheep are the most numerous livestock type in this landscape (a total of 295,900 in with stone walls predominating. Here, wet rushy pastures are of particular 2009 in comparison to 81,300 cattle and 4,200 pigs). Between 2000 and 2009 sheep importance for breeding waders such as lapwing, snipe, curlew, redshank numbers decreased by 90,600 (23 per cent), cattle numbers decreased by 12,300 (13 and oystercatcher. Extensive areas of predominantly ancient semi-natural per cent) and pig numbers decreased by 4,900 (54 per cent). woodland are concentrated on the ridges, slopes and valley sides of the many Source: Agricultural Census, DEFRA (2010) rivers present throughout the area. Woodlands here are dominated by oak, ash and birch with extensive amounts of wych elm and wild gean, especially 6.6 Farm labour along the Ribble, with alder and willow beside the Brock, Wyre and Calder. The In 2009 the majority of holdings are run by Principal Farmers (1,657) with only woodlands on the northernmost side of the Fells are particularly important 18 salaried managers being employed. Between 2000 and 2009 the number of for their rich assemblage of mosses and lichens. Pied and spotted flycatchers, salaried managers remained static at 18, full time workers decreased slightly redstart, tree pipit, tawny owl, great spotted woodpecker and sparrow hawk from 228 to 225, part time workers increased from 218 to 255 and casual / are all characteristic bird species associated with these woodlands. gang workers decreased from 218 to 104. Source: Agricultural Census, DEFRA (2010) Numerous rivers and watercourses provide habitats for salmon, brown and sea trout, as well as birds such as kingfisher, dipper, grey wagtail, common Please Note: (i) Some of the Census data is estimated by Defra so will not be accurate for every holding (ii) Data refers to Commercial Holdings only (iii) Data includes land outside of the NCA sandpiper and oystercatcher. Otters are also present along rivers on the belonging to holdings whose centre point is within the NCA listed. northern side of the Fells. The rivers make a significant contribution to the area together with the Lancaster Canal which supports an interesting array of locally rare aquatic plants such as flowering rush, greater spearwort, white water lily 7. Key habitats and species and various pond weeds.

7.1 Habitat distribution/coverage A number of reservoirs and disused gravel pits along the Wyre valley are also Small to medium sized hay meadows and permanent pasture fields are important as habitat for breeding great crested grebe and wintering wildfowl, defined by stone walls immediately adjacent to the Bowland Fells, which whilst the high density of field ponds between Preston and Garstang become hedgerows within valley bottoms and areas around settlements. provide an important habitat for aquatic plants, freshwater invertebrates Mature oak, ash and alder trees are common components of hedgerows. The and amphibians. Formal parkland surrounding modest country houses species rich hay meadows with pignut, yellow rattle, great burnet, ox-eye adds to the intensely managed character of the area. Typically consisting of daisy and lady’s mantle provide a splash of colour during the summer and open grassland with ponds and lakes, scattered trees of oak, ash, sycamore attract large numbers of butterflies. At higher elevations the improved pastures and lime, enclosed by blocks of secondary woodland, the parklands are

23 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

particularly important for their dead wood invertebrates, mosses and lichens. 7.3 Key species and assemblages of species Several heronries are also present. ■ Maps showing locations of UK BAP priority habitats are available at: Source: Bowland Fringe & Pendle Hill Countryside Agency Summary Statements; http://magic.defra.gov.uk/website/magic/ Forest of Bowland Natural Area Profile

■ Maps showing locations of S41 species are available at: 7.2 Biodiversity Action Plan (BAP) priority habitats http://data.nbn.org.uk/ The NCA contains the following areas of mapped priority habitats (as mapped by National Inventories). Footnotes denote local/expert interpretation. This will be used to inform future national inventory updates. 8. Settlement and development patterns Habitat Area (ha) % of NCA Broadleaved mixed & yew woodland 1,791 2 8.1 Settlement pattern (Broad Habitat) The settlement pattern is of small villages with isolated houses and farms Upland heathland 1,747 2 dotted around the winding country lanes. Many of the smaller villages and hamlets are linear in character and commonly take the form of terraced stone Coastal & floodplain grazing marsh 1,278 2 cottages along the main road. Blanket bog 973 1 Source: Countryside Character Area description; Countryside Quality Counts (2003 Lowland meadows 363 <1

Purple moor-grass & rush Pasture 351 <1 8.2 Main settlements Lowland calcareous grassland 132 <1 There are many villages dating from the 16th to 18th century, together with Upland hay meadow 129 <1 hamlets, farmsteads and also country houses and halls set in parkland. The largest settlements within the NCA are: Clitheroe, Longridge, Bentham, Whalley, Fens 103 <1 Caton, Grimsargh and Goosnargh. There are also many small villages and hamlets Upland calcareous grassland 92 <1 with populations of <1,000. The total estimated population for this NCA (derived Lowland raised bog 82 <1 from ONS 2001 census data) is: 55,281. Source: Countryside Character Area description; Lowland heathland 32 <1 Countryside Quality Counts (2003), Natural England (2012) Lowland dry acid grassland 22 <1 Source: Natural England (2011)

24 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

8.3 Local vernacular and building materials 9.2 Designated historic assets Isolated stone villages tend to be nestled into the escarpments and are This NCA has the following historic designations: commonly characterised by distinctive becks, greens and mills each with its own unique charm. On higher ground traditional stone barns are commonplace. The ■ 3 Registered Parks and Gardens covering 95 ha predominant building materials are stone and roofs are made of slate or, less ■  0 Registered Battlefield/s covering 0 ha commonly, stone flags. There has been some, limited, expansion of villages but ■ 39 Scheduled Monuments this has been done sympathetically using local materials. ■ 1274 Listed Buildings Source: Countryside Character Area description; Countryside Quality Counts (2003 Source: Natural England (2010)

9. Key historic sites and features ■ More information is available at the following address: http://www.english-heritage.org.uk/caring/heritage-at-risk/ 9.1 Origin of historic features The history of the landscape is evident in the long history of piecemeal http://www.english-heritage.org.uk/professional/protection/process/ colonisation reflected in the intricate small-medium scale fields with national-heritage-list-for-england/ widespread post medieval and ancient fields, particularly around Preston, and larger rectilinear Parliamentary enclosures. There are many archaeological sites particularly on the moorland fringes and in valleys where agriculture has been 10. Recreation and access less intensive as well as corridors such as the Ribble and Lune valleys which were important routes since the Roman period, the latter with small motte and 10.1 Public access bailey castles. A small number of industrial terraced settlements, for example Oakenclough, Dolphinholme and Galgate, are characteristic of the Calder Vale ■ 6 per cent of the NCA 4,728 ha is classified as being publically accessible. while lead mining remains and derelict lime kilns are found in the Ribble Valley. ■ There are 1,537 km of public rights of way at a density of 2 km per km2. Aspects of history likely to be most evident to the general public include, ■  There is 1 national trail within NCA. 19 km of the Pennine Bridleway falls Stonyhurst College, Gledstone Hall, Clitheroe Castle, large country houses set in within this NCA. their own parkland, such as Abbeysted, Ellel Grange, Waddow Hall, Bolton Park Sources: Natural England (2010) and Leagram Hall and smaller landscape features such as stone bridges. Source: Countryside Quality Counts Draft Historic Profile, Countryside Character Area description

25 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

The table below shows the breakdown of land which is publically accessible 11. Experiential qualities in perpetuity: 11.1 Tranquillity Access designation Area (ha) % of NCA Based on the CPRE map of Tranquillity (2006) the lowest scores are around the National Trust (Accessible all year) 0 0 main settlements and road routes. Common Land 1,371 2 A breakdown of tranquillity values for this NCA are detailed in the table below: Country Parks 110 <1

CROW Access Land (Section 4 and 16) 4,728 6 Category of tranquillity Score CROW Section 15 540 1 Highest value within NCA 127 Village Greens 7 <1 Lowest value within NCA -78 Doorstep Greens 0 0 Mean value within NCA 11 Forestry Commission Walkers 100 <1 Sources: CPRE (2006) Welcome Grants Local Nature Reserves (LNRs) 18 <1 ■ More information is available at the following address: http://www.cpre.org.uk/what-we-do/countryside/tranquil-places/in- Millennium Greens 0 0 depth/item/1688-how-we-mapped-tranquillity Accessible National Nature Reserves (NNRs) 0 0

Agri-environment Scheme Access 3 <1 11.2 Intrusion The 2007 Intrusion Map (CPRE) shows the extent to which rural landscapes Woods for People 197 <1 are ‘intruded on’ from urban development, noise (primarily traffic noise), and Sources: Natural England (2011) other sources of visual and auditory intrusion. This shows that large areas of Please Note: Common Land refers to land included in the 1965 commons register; the NCA are considered ‘disturbed’ with major transport corridors and urban CROW = Countryside and Rights of Way Act 2000; OC and RCL = Open Country and Registered development occurring throughout the NCA. A breakdown of intrusion values Common Land. for this NCA are detailed in the table below.

26 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

1960s 1990s 2007 % change Category of intrusion (%) (%) (%) (1960s-2007) Disturbed 8 21 23 15 Undisturbed 92 79 76 -16 Urban <1 <1 <1 <1 Sources: CPRE (2007)

Notable trends from the 1960s to 2007 are an increase in intrusion particularly along the M6 corridor and around Longridge, Clitheroe and the A59.

■ More information is available at the following address: http://www.cpre.org.uk/what-we-do/countryside/tranquil-places

27 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

12. Data sources

■ British Geological Survey (2006) ■ Sites of Special Scientific Interest, Natural England (data accessed in March 2011) ■  Natural Area Profiles, Natural England (published by English Nature 1993-1998 ) ■ Detailed River Network, Environment Agency (2008) ■ Countryside Character Descriptions, Natural England (regional volumes ■ Source protection zones, Environment Agency (2005) published by Countryside Commission/Countryside Agency 1998/1999) ■ Registered Common Land GIS data, Natural England (2004) ■  Joint Character Area GIS boundaries, Natural England (data created 2001) ■ Open Country GIS data, Natural England (2004) ■ National Parks and AONBs GIS boundaries, Natural England (2006) ■ Public Rights of Way Density, Defra (2011) ■ Heritage Coast Boundaries, Natural England (2006) ■ National Trails, Natural England (2006) ■ Agricultural Census June Survey, Defra (2000,2009) ■ National Tranquillity Mapping data, CPRE (2007) ■ National Forest Inventory, Forestry Commission (2011) ■ Intrusion map data, CPRE (2007) ■ Countryside Quality Counts Draft Historic Profiles, English Heritage (2004)* ■ Registered Battlefields, English Heritage (2005) ■  Ancient Woodland Inventory, Natural England (2003) ■ Record of Scheduled Monuments, English Heritage (2006) ■ BAP Priority Habitats GIS data, Natural England (March 2011) ■ Registered Parks and Gardens, English Heritage (2006) ■ Special Areas of Conservation data, Natural England (data accessed in March ■ World Heritage Sites, English Heritage (2006) 2011) ■ Incorporates Historic Landscape Characterisation and work for preliminary ■ Special Protection Areas data, Natural England (data accessed in March 2011) Historic Farmstead Character Statements (English Heritage/Countryside ■  Ramsar sites data, Natural England (data accessed in March 2011) Agency 2006)

Please note all figures contained within the report have been rounded to the nearest unit. For this reason proportion figures will not (in all) cases add up to 100%. The convention <1 has been used to denote values less than a whole unit.

28 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Supporting document 2: Landscape change

Recent changes

Trees and woodlands Boundary features ■ Riverside woods have declined due to excessive grazing and lack of ■ The areas important and distinctive stock of field boundaries, although management, with smaller, semi-natural woodlands being particularly still largely intact is in decline. Surveys by the Forest of Bowland AONB vulnerable to grazing by stock and deer. In addition heavy grazing and drainage (2007) indicate that more than 50 per cent of field boundaries are in of upland areas has led to increased erosion of riverbanks and riverside trees. need of restoration; these are mainly within the Bowland Fringe and are predominantly hedgerows although extensive wall restoration is needed too, ■ Many prominent, mature flood plain, parkland and hedgerow trees are over especially on higher ground. Artefacts such as gateposts, sheepfolds, stone mature or in decline. There is little evidence of regeneration in hedgerows or troughs and parish boundary markers are also at risk. of replacement planting. ■ The most frequent Environmental Stewardship agreements for linear features ■ About 23 per cent of the woodland is Ancient Woodland (1,165ha), of this as at March 2011 were for hedgerows (557,190 m) and stone walls (513,692 m). almost a quarter of the ancient woodland is plantation on ancient woodland sites (262 ha) The proportion of these sites covered by a Woodland Grant ■ The estimated boundary length for the NCA is about 6,019 km. Total length of Scheme agreement increased from 1999 to 2003 from 8 per cent to 16 per cent. Environmental Stewardship agreements for linear features as at March 2011 is equivalent to about 21.2 per cent of this total.

29 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Agriculture Semi-natural habitat ■ The primary land use within the NCA is grass and uncropped land (96 per ■ ■ Semi-natural meadow habitats have been lost due to farm amalgamation and cent) and there was a 1 per cent decrease in the total farmed area between agricultural intensification, particularly in the flood plain and lowland farmland 2000 and 2009. landscape, which are dominated by dairying. Herb-rich flood plain meadows and hay meadows are at particular risk from agricultural improvement. ■ Between 2000 and 2009 there was a 10 per cent decrease in the number of all livestock production farm types with an associated significant decrease ■ Moorland fringe landscapes are vulnerable to change due to declining in livestock numbers. There was however a slight increase in all arable, agricultural income. Farm decline and abandonment may adversely affect horticulture, mixed and other farm types. There was a 41 per cent decrease the characteristic diverse mosaic of small pastures, meadows and scrub in the number of dairy holdings and an apparent shift from lowland to LFA woodlands. livestock grazing. ■ Changes include decline of moorland / bog habitats in the moorland fringes Settlement and development and loss of field ponds / wetlands elsewhere. ■ Some older farm buildings have fallen into disrepair and conspicuous modern farm buildings have affected the settings of unspoilt traditional Historic features farmsteads. ■ In 2003 about 71 per cent of historic farm buildings remained unconverted. About 95 per cent were intact structurally. ■ Tourism and recreation are an important part of the local economy, and the increased pressures associated with the expansion of facilities at key sites, ■ In 1918 about 2 per cent of the NCA was historic parkland. In terms of its share such as Beacon Fell, Brockbottom, Jeffrey Hill and Kemple End requires of the resource the NCA was ranked 75. By 1995 it is estimated that 24 per sensitive management to ensure attendant noise, erosion and traffic are cent of the 1918 area had been lost. In 2003 about 4 per cent of the remaining controlled whilst encouraging access to and enjoyment of the natural parkland was covered by a Historic Parkland Grant, and 9 per cent was environment. included in an agri-environmental scheme.

■ The incremental effective of many small-scale new developments has resulted in dilution of traditional vernacular styles.

30 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Rivers ■ ■ The NCA does not overlay any major aquifers.

■ Principal surface water resources within the NCA are the catchments of the rivers Lune, Wyre and Ribble. The tributaries of the River Lune within the NCA have ‘no water available’. Actual abstractions (as opposed to licensed abstractions) in the Lune CAMS area as a whole are mainly for public water supply (particularly the Lancaster area), industry, aquaculture and energy generation. The Lancaster area is supplied from Langthwaite reservoir, which is filled from the River Lune intake at Caton. The River Lune can support flows in the River Wyre via pipeline transfers.

■ The River Wyre and its tributaries within the NCA are classified as ‘over abstracted’, ‘over licensed’ or ‘no water available’. Water abstraction within the Wyre CAMS area is dominated by public water supply but is also used for industry, agriculture, fish farming and topping up the Lancaster Canal.

■ The River Ribble catchment within the NCA generally has ‘water available’ although its tributary the River Hodder is ‘over licensed’ River Lune Minerals ■ There are a number of sand and gravel extraction sites within the NCA, mainly confined to the valley bottoms to the south. There are also clay pits and the most prominent of these is at Claughton Brickworks where aerial ropeways extend from Claughton Moor across the A683 to the brickworks.

31 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Drivers of change

Climate change ■ Evidence from UK Climate Impacts Programme (UKCP09) shows that over ■ Prolonged periods of drought are likely to have an adverse effect on peatland the coming century the climate in NW England is expected, on average habitats, making them more prone to soil erosion and wildfire events. to become warmer and wetter in winter and hotter and drier in summer. Under the medium emissions scenario by 2080: mean winter temperatures ■ Potential for more favourable conditions for crops and other farming will increase by 2.6°C, mean summer temperatures will increase by 3.7°C, practices not presently possible within this area. winter precipitation will increase by 16 per cent, summer precipitation will decrease by 22 per cent and there will be an increase frequency of extreme ■ Potential change to cropping patterns and types of crops in response to events (floods/droughts). climate change altering the character of the landscape.

■ Hotter, drier summers may lead to reduced groundwater and surface drying ■ Threat to trees from changing pests and diseases and extreme weather events. out of peat bog habitats, which can release carbon into the atmosphere. ■ There may be increased pressures for renewable energy development and ■ Small fragmented patches of habitat and poor-quality habitat are vulnerable a growing demand for bio-energy crops. to loss of biodiversity due to changes in rainfall and temperature.

■ Periods of heavy rain may lead to an increased risk and frequency of flooding in lowland areas and river valleys and may also result in increased soil erosion and pollution of water courses downstream. There is also a potential increased risk of landslides during times of increased rainfall.

32 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

benefits of increasing opportunities for visitors to reconnect with nature. Other key drivers

■ ■ Possible abandonment of hill farming in the face of economic pressures is ■ Changing agricultural policy and farm subsidies creates uncertainty and likely to affect species mix and character of upland grassland and moorland. pressures on livestock farming. Increasing emphasis on food security and bio-energy crops. ■ Lack of management of semi-natural clough woodland and lack of restoration of plantation on ancient woodland sites may reduce wildlife ■ Pressure for new development and building conversion in an open exposed value. In addition potential changes to wood product markets may influence landscape can be visually intrusive. Sympathetic design of new buildings woodland management. in keeping with landscape character with appropriate siting and screening should be sought. ■ Agricultural specialisation, intensification and farm amalgamation may result in a loss of semi-natural habitat and cultural features. ■ Increasing pressure for commercial-scale renewable energy infrastructure such as windfarms ■ Heavy fertiliser use and diffuse pollution may lead to loss of biodiversity both on and off agricultural land as well as affecting water quality. ■ The exploitation of mineral deposits has the potential to affect the landscape character of the area and will require sensitive development. ■ There is an opportunity to increase tree and woodland cover to provide multiple benefits including reconnecting fragmented habitats increasing ■ There is substantial pressure for urban expansion close to Preston / resilience and improving water quality. Longridge, as well as some development pressure on the southern margins of the NCA and within the larger historic villages. ■ Pressure on key destinations needs to be sensitively managed to avoid erosion and potential damage to archaeological sites, loss of habitats, tranquillity and diminished visitor experience, whilst balancing the positive

33 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Supporting document 3: Analysis supporting Statements of Environmental Opportunity

The following analysis shows the projected impact of Statement of Environmental Opportunity on ecosystem service provision:

Ecosystem Service

Statement of Environmental Opportunity Food provision Timber provision Biomass provision Water availability Genetic diversity Climate regulation erosion soil Regulating Regulating soil quality Regulating water quality Regulating water flow Pollination Pest regulation coastal erosion Regulating Sense of place/inspiration Sense of history Tranquility Recreation Biodiversity Geodiversity

SEO 1: Protect and enhance the distinctive landscape character of the Bowland Fringe and Pendle Hill NCA for its sense of place, historical and cultural heritage, tranquillity, accessibility and *** *** *** *** ** *** ** ** ** *** *** *** ** ** *** ** ** recreational opportunities.

SEO 2: Safeguard, manage and enhance the area’s important habitats, including blanket bog, wet heath, waterbodies and woodland, to provide benefits for climate change, flood ** ** *** ** ** * ** *** ** ** *** *** ** *** ** ** * regulation, soil quality and erosion, and water quality.

Note: Arrows shown in the table above indicate anticipated impact on service delivery: = Increase = Slight Increase = No change = Slight Decrease = Decrease. Asterisks denote confidence in projection (*low **medium***high) ° symbol denotes where insufficient information on the likely impact is available.

Dark plum = National Importance; Mid plum = Regional Importance; Light plum = Local Importance

34 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Ecosystem Service

Statement of Environmental Opportunity Food provision Timber provision Biomass provision Water availability Genetic diversity Climate regulation erosion soil Regulating Regulating soil quality Regulating water quality Regulating water flow Pollination Pest regulation coastal erosion Regulating Sense of place/inspiration Sense of history Tranquility Recreation Biodiversity Geodiversity

SEO 3: Manage and enhance the landscape character and biodiversity of the farmed environment, with its mosaic of pastures and meadows, and strong field patterns defined by ** ** ** ** ** ** ** ** ** ** ** *** ** *** ** ** ** drystone walls and hedgerows, to improve ecological networks and strengthen landscape character.

SEO 4: Retain riparian and wetland habitats, and ensure that they are well managed and well connected to the high density of waterbodies. Enhance the network to further increase *** ** ** *** ** ** *** * ** *** * ** ** ** ** *** * biodiversity, improve its ability to buffer pollution, increase flood mitigation and improve water quality.

Note: Arrows shown in the table above indicate anticipated impact on service delivery: = Increase = Slight Increase = No change = Slight Decrease = Decrease. Asterisks denote confidence in projection (*low **medium***high) ° symbol denotes where insufficient information on the likely impact is available.

Dark plum = National Importance; Mid plum = Regional Importance; Light plum = Local Importance

35 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Landscape attributes

Landscape attribute Justification for selection

Undulating, rolling landscape with local variation  The combination of topography, tree cover and field enclosure creates a sense of intimacy in contrast to the created by numerous river valleys and by the expanse of the coastal plain and exposed moorland heights. moorland outliers of Beacon Fell, Longridge Fell and  13 rivers flow through the NCA totalling 172 km. Pendle Hill.  Elevation ranges from 9.23 m to 549.66 m.

The Bowland Fells provide a dramatic backdrop to the  The NCA is a transitional landscape which wraps around the upland core of the Bowland Fells. north with extensive views across the river valleys and  The transition from plain to fell landscape is rapid and reflects the existence of a substantial geological Lancashire plain below. boundary fault which separates the soft Permo-Triassic rocks from the harder Carboniferous rocks.

Drumlins on the northern edge of the area.  Glacial drift deposits have given rise to a repetitive pattern of rounded hills or drumlins which creates a distinctive rolling landform characteristic of the northern edge of the NCA associated with the rivers Lune and Ribble.

Strong mounded outcrops or ‘reef knolls’ of limestone  The Clitheroe Knoll Reefs SSSI comprises a road cutting and four small hills between the villages of Worston form distinct landscape features in the Ribble and and Downham near the market town of Clitheroe. The hills are important examples of an early Carboniferous Hodder valleys. “knoll reefs” complex. In conjunction with other well exposed sites in the Clitheroe area, the complex shows one of the best examples of such reefs in Northern England.

Ancient semi-natural woodland dominated by oak, ash  Calf Hill and Cragg Woods SSSI/SAC occupies the north and south-facing slopes of a steep-sided valley and alder. above the River Conder, a tributary of the River Lune. The woods support one of the most extensive stands of upland oak-birch woodland in Lancashire, as well as large stands of valley alder woodland with wet birch woodland.

Isolated country houses set in formal parkland.  Large country houses set in their own parkland include Abbeystead House, Ellel Grange, Waddow Hall, Bolton Park and Leagram Hall.

36 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Landscape attribute Justification for selection

Distinctive boundary features including drystone  The intricate small-medium scale fields reflect a long process of piecemeal colonisation and assartment. walls, metal railings and hedgerows.  557,190 m of hedgerow under Environmental Stewardship as at March 2011.  513,692 m of dry-stone wall under Environmental Stewardship as at March 2011.  Metal railings around estate boundaries are characteristic of the southern and western edges of the NCA.  Medium to small-scale fields are defined by hedgerows with mature hedgerow trees.

Land use is mainly permanent, improved pasture for  Most of the NCA (86 per cent) is medium grade (3 or 4) agricultural land. livestock and dairy farming.  In 2009, 52 per cent of the commercial farm holdings were livestock and 23 per cent dairy.

Lush hay meadows and some rough grazing at higher  North Pennine Dales Meadows SAC encompasses the range of variation exhibited by Mountain hay elevations. meadows in the UK and contains the major part of the remaining UK resource of this habitat.  Wet rushy pastures of particular importance for breeding waders.

Numerous rivers, ox-bow lakes, reservoirs and field  13 key rivers flow through the NCA totalling 172 km. ponds.  There is a high density of characteristic field ponds north of Preston.

A network of winding hedge-lined lanes connect  Isolated stone villages tend to be nestled into the escarpments and are commonly characterised by small, often linear, villages, hamlets and scattered distinctive becks, greens and mills each with their own unique charm. farmsteads, mostly built in local stone. Traditional stone barns are commonplace on higher ground and are of stone with slate or stone flag roofs.

37 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Landscape opportunities

■ Protect the distinctive rolling landform from development on ridgelines ■ Species-rich hay meadows form valuable landscape and ecological areas. and hilltops to maintain the predominantly open character of the landscape, by minimising vertical elements and built development. ■ The restoration and management of the characteristic field ponds north of Preston should be addressed. ■ Protect views to and from the area from large-scale developments that may erode the open and undeveloped character of the area. ■ Control built development to maintain vernacular styles and materials and the character of the build environment locally. ■ Promote and protect the geological heritage of the area. ■ There are opportunities for the appropriate management of recreational ■ The conservation and management of riparian woodland, semi-natural and sites so visitor pressures are minimised, and benefits and visitor ancient woodland, hedgerows, hedgerow trees and avenues should be experiences enhanced. considered.

■ Maintain the areas highly distinctive stock of field boundaries and associated features, respecting differences in local style.

38 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Ecosystem service analysis

The following section shows the analysis used to determine key ecosystem service opportunities within the area. These opportunities have been combined with the analysis of landscape opportunities to create Statements of Environmental Opportunity.

Please note that the following analysis is based upon available data and current understanding of ecosystem services. It does not represent a comprehensive local assessment. Quality and quantity of data for each service is variable locally and many of the services listed are not yet fully researched or understood. Therefore the analysis and opportunities may change upon publication of further evidence and better understanding of the inter-relationship between services at a local level.

Principle Assets/ services offered attributes: main by opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Food Sustainable This is an important area Regional Livestock production systems Work with the local farming community Food provision provision sheep and cattle for rearing livestock. Soils prevail over a large area of the to achieve appropriate grazing regimes to grazing are relatively poor and this NCA and have strong associations produce food and other multiple benefits. Biodiversity combined with the high with the area’s cultural services. rainfall rate means there is In many locations well-managed Encourage the development and Climate regulation little opportunity for arable livestock production systems have promotion of supply chains and markets crops. 62 per cent of the land the potential to increase the overall for high-quality local produce. Regulating soil is Agricultural Grade 4 or 5 food provision of the NCA whilst erosion and 37 per cent is Grade 3. benefiting many of the other key ecosystem services that the area Sense of place supports. Inappropriate stocking regimes, with insufficient stock Sense of history management, may have significant detrimental effects on many key environmental services including biodiversity, soil erosion, water quality and climate regulation.

39 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Assets/ Principle services attributes: offered by main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Timber Existing 7 per cent of the NCA is Regional Much of the broadleaved woodland is on There is scope for some woodland Timber provision provision woodland under woodland cover. ridge, slopes and valley sides. With much of creation on some slopes, but this and forestry Areas of semi-natural the land used for livestock rearing there are needs to avoid peat areas, and to Regulating water estates woodland are commonly limited places for woodland creation. avoid impacting on other sites of flow associated with managed biodiversity or historic value. estates and parkland. Climate regulation Extensive areas of ancient There is scope to restructure semi-natural woodland are conifer plantations in the Biodiversity concentrated on the ridges, moorland outliers and rolling slopes and valley sides of upland farmland in order to the rivers. Several large increase their broadleaved blocks of conifer plantation component and soften their edges. are present, mainly in the south and north-west, some There are opportunities for of which are managed for woodland management and productive timber. restoration of ancient woodland.

40 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Assets/ Principle services attributes: offered by main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Biomass Existing The existing woodland cover Local Supply chains and markets for local wood There is an opportunity to Biomass energy energy woodland and (7 per cent of the NCA) offers fuel are currently limited. Development increase production of biomass forestry estates moderate potential for the of these is required to maximise the as a bi-product of commercial Biodiversity provision of biomass, both potential for woodfuel as a by-product of timber production and through through bringing unmanaged commercial forestry. introducing management in woodland under management currently unmanaged woodlands. and as a bi-product of commercial Sensitive management of existing timber production. unmanaged broadleaved woodland also offers potential for wood fuel.

Biomass production in the area is currently low; however the area has a medium to high potential yield for short rotation coppice. Increased provision of SRC for fuel has the potential to increase climate regulation, but must ensure not to have a negative impact on provision of other ecosystem services for example food supply, biodiversity, sense of place. For information on the potential landscape impacts of biomass plantings within the NCA, refer to the tables on the Natural England website at: http:// www.naturalengland.org.uk/ourwork/ farming/funding/ecs/sitings/areas/ default.aspx

41 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Assets/ Principle services attributes: offered by main opportunities contributors Main Service to service State beneficiary Analysis Opportunities

Water Reservoirs The NCA does not overlay any major Regional High rainfall combined with the Opportunities to block Water availability availability aquifers although the Carboniferous impervious rock of the Bowland Fells moorland grips to increase Rivers and Limestone forms minor (Secondary A) makes the area important for providing holding capacity of the Regulating water streams aquifers in this area. Principal surface clean drinking water as well as supplying moorland habitats over the quality water resources within the NCA are industry, aquaculture, energy generation medium to long term. Blanket bog the catchments of the rivers Lune, and topping up the Lancaster Canal. Biodiversity Wyre and Ribble. The tributaries of Land management practices are key Ensure that moorland High level of the River Lune within the NCA have to improving rates of infiltration and habitats, especially blanket Climate regulation precipitation ‘no water available’. The River Wyre storing surface water. For example bog are well vegetated and and its tributaries within the NCA are United Utilities’ Sustainable Catchment under good environmental Regulating soil classified as ‘over abstracted’, ‘over Management Programme (SCaMP) management, increasing the erosion licensed’ or ‘no water available’. The applies an integrated approach to capacity of habitats to retain River Ribble catchment within the catchment management across all of water. Regulating water NCA generally has ‘water available’ their water catchment land. flow although its tributary the River Hodder is ‘over licensed’.

Genetic Rare sheep and The Lonk sheep is a hardy hill National Rare breeds in this area provide meat, Encourage the promotion and Genetic diversity diversity cattle breeds breed native to Lancashire and well high quality local produce and hardy development of supply chains established in Bowland. breeding ewes to lowland areas. and markets for high quality Food provision local produce Sense of place

Sense of history

42 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Principle services offered by Assets/attributes: main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Climate regulation Soils including upland In this NCA soil carbon National On free draining, slightly acidic Ensure that all areas of Climate regulation peaty soils and organic levels are generally soils measures could be taken to blanket bog are under good soils low (0-5 per cent), improve carbon sequestration by environmental management Regulating water reflecting the mineral increasing organic matter input and which improves the habitat’s quality Existing woodland and soils covering 72 per by reducing the frequency/extent ability to actively sequester CO2 other vegetation cent of its area. Small of cultivation, although cropping is from the atmosphere, whilst Water availability areas of higher soil limited in its extent. retaining significant volumes in carbon adjoining the storage of greenhouse gases. Biodiversity peaty upland area of It is important to ensure that the the Bowland Fells, are existing woodlands are actively Prioritise the restoration of bare Regulating soil associated with the managed to enhance both and eroded peatland habitats. quality NCA’s slowly permeable biodiversity and their ability to store wet very acid upland and sequester carbon. The area of Encourage sustainable grazing Regulating soil soils with a peaty woodland cover could be expanded regimes on permanent pasture erosion surface (15 per cent of where appropriate. with a low input of artificial NCA) and the very acid fertilizer. loamy upland soils with a wet peaty surface (6 Ensure existing woodlands are per cent of NCA). under good management.

It will also be important Create new native woodland to conserve the carbon where this sits well alongside within the loamy and landscape, biodiversity and clayey flood plain soils historic environment interests. with naturally high groundwater (1 per cent Expand and restore wetland of NCA). Carbon storage habitats. will also be provided by the NCA’s woodland (7 per cent of its area).

43 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Principle services Assets/attributes: offered by main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Regulating Slowly permeable The majority (69 per cent) of the soils Regional Measures will be Take steps to restore bare or eroded Regulating soil soil erosion wet very acid covering this NCA are not highly susceptible beneficial that retain peat. erosion upland soils with to erosion. water in situ; ensure good a peaty surface vegetative cover and avoid Manage moorland to ensure good Regulating water Very acid loamy The slowly permeable wet very acid upland over-grazing/ trampling or vegetative cover and reduce high quality upland soils with a soils with a peaty surface (15 per cent) damage by mechanised rates of run-off by restoring the wet peaty surface often found on the moorland plateau tops activities or burning. hydrology and ecology of peatland Regulating soil Freely draining are at risk of gullying/ hagging (and loss of habitats. quality slightly acid loamy particulate organic matter) where surface soils Freely draining vegetation is damaged or lost. Unsustainable Seek opportunities to establish Regulating water lime-rich loamy burning practices, overgrazing and drainage permanent grassland and flow soils of these soils (for example through gripping) woodland along watercourses. may also result in increased oxidation of Biodiversity carbon and soil wastage. Manage pastures in ways that build up organic matter and avoid Climate regulation Erosion is equally prevalent on the very acid compaction, for example by loamy upland soils with a wet peaty surface (6 reducing grazing pressures. per cent) often found on steep slopes, where a combination of rapid runoff and easily Increase cover of native broadleaved damaged peat layers results in soil erosion. woodland and trees targeting areas with high risk of soil erosion. The freely draining slightly acid loamy soils (5 per cent) and the lighter textured (less clayey) variants of freely draining lime-rich loamy soils (1 per cent) can erode easily on steep slopes, especially where vegetation is removed, soil is compacted or where organic matter levels are low after continuous cultivation. There is also the potential for wind erosion on some coarse textured, cultivated variants of the former soil type.

44 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Principle services Assets/attributes: offered by main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Regulating Slowly permeable The slowly permeable seasonally Local For loamy and clayey soils, Manage moorland habitats to Regulating soil soil quality seasonally wet acid wet acid loamy and clayey soils (57 management measures that increase safeguard the carbon-rich soils quality loamy and clayey per cent of the NCA) may suffer organic matter levels can help and encourage peat-forming soils compaction and/ or capping as reduce these problems. plants. Regulating water they are easily damaged when quality Slowly permeable wet. In turn this may lead to For wet and peaty soils measures Ensure that the management wet very acid upland increasingly poor water infiltration should be encouraged that retain of the pastures and meadows Climate regulation soils with a peaty and diffuse pollution as a result of water in situ and potentially raise on the moorland fringes will surface surface water run-off. water levels ; ensure good vegetative encourage the build up of Regulating water cover and avoid over grazing/ organic matter, through for flow Conversely, the slowly permeable trampling or damage by mechanised instance extensive grazing wet very acid upland soils with activities regimes, which will also reduce Regulating soil a peaty surface (15 per cent) are the level of poaching by erosion at risk of loss of organic matter livestock. through climate change and soil Water availability erosion. Avoid carrying out mechanised activities such as trafficking that Biodiversity will cause compaction of soils, especially in wet conditions.

45 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Assets/ Principle services attributes: offered by main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Regulating The many Ecological river water quality is Regional Steep agricultural land can be Re-vegetate bare peat and improve Regulating water water streams and moderate or poor in much of the associated with high rates of run- the management of degraded quality quality rivers River Lune catchment although the off into adjacent water courses peatland habitats, managing existing rivers Wenning and Greta have good especially after heavy rainfall, moorland vegetation to enhance its Regulating soil Moorland, water quality. when this can be associated biological condition, reducing the erosion rough grazing with high rates of soil erosion, degree of water coloration within and woodland Langthwaite Reservoir is of moderate high turbidity and increased associated water courses. Regulating water ecological quality. The River Conder sediment load impacting on areas flow is of moderate quality as is the River downstream. Seek opportunities to establish Calder (a tributary of the Rive Wyre) Degradation of peat soils can be permanent grassland (non intensive) Biodiversity whilst the remainder of the Wyre associated with increased water scrub and woodland along water is of good quality. The River Ribble coloration which water supply courses. Climate regulation downstream of its confluence with companies have to treat before Tosside Beck and the beck itself are the water enters the supply. Ensure appropriate grazing levels for Regulating soil of moderate quality, the remainder of United Utilities’ Sustainable a well vegetated sward. quality the Ribble catchment within the NCA Catchment Management having good ecological quality. Programme (SCaMP addressed Manage nutrients in farmsteads and Biodiversity many of these issues by applying on improved pastures. The chemical status of groundwater is an integrated approach to Water availability poor in the north and west of the NCA catchment management across all Increase area of native broadleaved but good in the south and east. of their water catchment land. woodland and scrub, targeted at areas of high soil erosion.

46 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Assets/ Principle services attributes: offered by main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Regulating Many rivers This NCA surrounds the Bowland Fells Regional Flood hazard in the Lune Slow down run-off from the Regulating water water flow and streams NCA and contains the middle part of rivers catchment within this NCA exist moorlands by blocking grips and flow that drain that upland area with its steep along the rivers Wenning in increasing the storage capacity topography and narrow flood plains which Wennington, Wray, Hornby and of soils by raising water table Regulating soil combine with waterlogged moorland soils Caton. Downstream flood risk levels. erosion and high rainfall to produce watercourses exists in Halton and Lancaster that respond rapidly to rainfall, increasing on the lower Lune as well as low Seek opportunities to expand Regulating water fluvial flood risk. lying agricultural land. areas of wetland habitats quality including blanket bog on the The river Lune in the north of the NCA has River flooding from the Wyre has moors and reedbeds, wet Water availability its source in the uplands of the Cumbria historically been a concern in pastures and woodland along High Fells and Howgill Fells and enters the Garstang, St Michaels-on-Wyre the valley bottoms. Biodiversity sea at Morecambe Bay, its tributaries the and Great Eccleston. Floodrisk Hindburn, Wenning, Greta and Leck Beck also exists at Galgate on the River Seek opportunities which allow Regulating soil drain the northern slopes of the Bowland Conder. rivers to follow natural courses quality Fells and the south west part of the and re-engage with their flood Yorkshire Dales. The river Wyre in the west Flood risk on the River Ribble plains. Climate regulation of the NCA and its tributaries the Calder is concentrated downstream in and Brock drain the western and south Preston and Ribchester. Ensure fell habitats and wetlands western slopes of the Bowland Fells along support a well vegetated sward with the Conder. The southern and eastern Improving the management and to enhance infiltration and parts of the NCA contain the River Ribble, control of flood waters in this NCA evapotranspiration and slow which has its source in the Yorkshire Dales will benefit the settlements further flows through increased surface and its tributaries the River Hodder and downstream in other NCAs. roughness. Tosside Beck, which drain the southern and eastern slopes of the Bowland Fells NCA. Continued on next page...

47 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Assets/ Principle services attributes: offered by main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Regulating ... continued from previous page water flow Opportunities exist to address moorland and upland pasture management and there is some scope for creating opportunities for rivers to re-engage with their flood plains or creating wetlands adjacent to watercourses. An example of such a project is Long Preston Deeps which has been used as a demonstration site to encourage more land owners to undertake restoration works on their land, reconnecting the river to the flood plain.

Restoration of moorland habitat further upstream in the Bowland Fells NCA, where many of the rivers arise, is also key to addressing flood risk in this NCA and further downstream.

Pollination Semi-natural Bowland Fringe has a diverse landscape Local Of value largely to biodiversity Seek opportunities to expand Pollination habitats including herb-rich hay meadows and rather than food production in areas of species-rich grassland lush pastures, broad-leaved woodlands, this NCA. Ensure habitats are in on the moorland fringes and Biodiversity parkland and water bodies which provides good condition and look for ways within valleys; also road verge good habitat for pollinating insects and to expand them. management and small sites other invertebrates. However with limited within villages. crops and orchards requiring pollination, this service is of limited importance for food production in this NCA.

48 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Principle services offered by Assets/attributes: main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

A sense Undulating rolling The area has a strong and distinctive National A sense of place is provided by the There is an opportunity Sense of place of place/ landscape landscape character and over half undulating, rolling landscape which to maintain a sense of inspiration (38,175 ha) of the NCA falls within the skirts the edge of the Bowland place, valued by local Recreation Many river valleys Forest of Bowland AONB. Fells forming a dramatic backdrop. people and visitors, There are sharp variations in the by conserving the Sense of history Moorland outliers, reef local landscape resulting from the patchwork and variety knolls, drumlins river valleys and numerous small of landscape features Biodiversity hills/moorland such as Pendle Hill, which give the NCA Picturesque villages Longridge and Beacon Fell to the its distinctive sense of Tranquillity south. place. Attractive country houses Food provision with well maintained Strong outcrops or ‘reef knolls’ Also see opportunities formal parkland and limestone beds form distinct for: landscape features within the Ribble and Hodder valleys, whilst   Sense of history to the north, drumlins characterise   Recreation the area.   Tranquillity   Food provision Picturesque villages and a small   Biodiversity number of industrial settlements   Geodiversity sit alongside attractive country houses often set within extensive semi-natural woodland and well maintained formal parkland. Such houses have well-defined estate boundaries, enclosed by either belts of woodland or metal estate fencing; the latter is a particular characteristic to the south and west with dry-stone walls elsewhere.

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49 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Principle services offered by Assets/attributes: main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

A sense ... continued from previous page of place/ inspiration The landscape is intensively managed and largely of permanent improved pasture for dairy and livestock farming with herb- rich, small to medium sized hay meadows defined by well maintained hedgerows with mature hedgerow trees, and rough grazing at higher levels.

Woodland forms a significant landscape element within the area; semi-natural woodland much of which is ancient is evident in valley bottoms, side valleys and ridges while hedgerow trees, tree-lined avenues and riverside trees and blocks of coniferous woodland give the NCA a well-wooded appearance. Other prominent landscape features include ox-bow lakes, reservoirs, disused gravel pits and field ponds north of Preston.

50 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Principle services offered by Assets/attributes: main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Sense of Archaeological sites The history of the landscape is evident in Regional The area is well known There are opportunities to Sense of history history the long history of piecemeal colonisation for its many layers of protect, manage and interpret Small villages, hamlets reflected in the intricate small-medium visible history, resulting the many layers of historic Sense of place and isolated farmsteads scale fields with widespread post in a range of structures evidence. built in characteristic medieval and ancient fields, particularly and features. The main Recreation local stone around Preston, and larger rectilinear emphasis will be on There are opportunities to Parliamentary enclosures. protecting features, ensure that the restoration Network of winding but also on interpreting of vernacular buildings is hedge-lined country There are many archaeological sites them for a wider public carried out using local styles lanes particularly on the moorland fringes and audience. and appropriate materials, in valleys where agriculture has been and that land management A few industrial terraced less intensive as well as corridors such as practices and developments settlements the Ribble and Lune valleys which were such as tracks do not damage important routes since the Roman period, archaeological evidence or Large country houses set the latter with small motte and bailey historic features. in their own parkland castles. There are opportunities to use Settlements consist of small villages, the Pennine Bridleway and the hamlets and scattered isolated farmsteads public rights of way network built in characteristic local stone. These to gain access to, reveal are well integrated into the landscape and interpret the area’s rich and connected by a network of winding history. hedge-lined country lanes with traditional stone barns with stone flag or slate roofs on higher ground. A small number of industrial terraced settlements - Oakenclough, Dolphinholme and Galgate – are characteristic of the Calder Vale while lead mining remains and derelict lime kilns are found in the Ribble Valley.

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51 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Principle services offered by Assets/attributes: main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Sense of ... continued from previous page history Aspects of history likely to be most evident to the general public include Stoneyhurst College, Gledstone Hall, Clitheroe Castle, large country houses set in their own parkland, such as Abbeystead, Ellel Grange, Waddow Hall, Bolton Park and Leagram Hall, and smaller landscape features such as stone bridges.

There are also sites that survive as isolated reminders of the medieval heritage of the Forest of Bowland, for example the Cistercian monastery at Sawley.

Tranquillity Wooded river valleys Tranquillity and intrusion levels have National A sense of tranquillity There are opportunities to Sense of declined; undisturbed areas have is likely to be most retain the sense of remoteness tranquillity Parklands decreased from 92 per cent in the 1960s associated with the and tranquillity by protecting to 76 per cent in 2007. The lowest areas wooded river valleys as the areas from inappropriate Sense of place Picturesque villages and of tranquillity lie along the major road well as the parklands, development. hamlets corridors such as the M6, A65 and A59 picturesque villages and Biodiversity as well as around the towns of Clitheroe hamlets on undulating Opportunities exist to and Longridge. lowland farmland and promote the calming and Recreation some small-scale and restorative effect that contact intimate landscapes in the with tranquil and sensory Lune and Ribble valleys. environments have on visitors’ health and wellbeing.

52 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Principle services Assets/attributes: offered by main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Recreation Pennine Bridleway Recreation is supported by the Pennine Regional There is scope to improve There are opportunities to Recreation Bridleway (19 km lies in this NCA). There the provision of a range of improve access by ensuring A network of rights are 1,537 km of rights of way with a recreational opportunities that paths are maintained Sense of history of way density of 2 km per km². Open access and to provide interpretation and well signposted, and land covers 6.4 per cent of the NCA of the many elements of the that some surfaced paths are Regulating soil Open access land (4,728ha). landscape. provided for use by all levels erosion Locally accessible of ability and interest at key greenspace in Cycling is popular with increasing Local greenspace provides a locations. Regulating soil addition to the open opportunities for off-road cycling venue for local communities quality countryside includes along bridleways. Road cycling is also to engage in recreational and There are opportunities to 1 country park and 2 a popular pursuit, especially on the outdoor education activities provide interpretation of Regulating water Local Nature Reserves officially designated ‘quiet lanes’ around close to where they live, the landscape and its many quality Chipping and Downham, and on the allowing them to enjoy contact features, especially historic more challenging Tour of Pendle Race. with the natural environment, ones, enabling visitors to Biodiversity and to play an active role in its understand and enjoy its There are opportunities for horse-riding future management. character. along the network of greenways and bridleways. Local greenspace provides opportunities for recreation Other popular activities include: bird and outdoor education close watching, fishing, gliding and shooting. to where people live, allowing In addition there is a developing local communities to enjoy network of tramper trails that are their environment, take action suitable for people using off-road to improve it, and to benefit mobility scooters and pushchairs. from the health and social rewards it affords them. In addition to the open countryside, several areas of accessible greenspace exist within the NCA, with 2 LNRs providing venues for recreational and educational activities close to the conurbation of Clitheroe, with Beacon Fell Country Park offering a larger facility nearby.

53 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Principle services Assets/attributes: offered by main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Biodiversity 1 SPA BAP priority habitats cover National/ Improving the biological condition Improve the area of designated Biodiversity 6,000 ha (8 per cent) of the international of the biodiversity resource is habitat in favourable biological 2 SACs NCA and include 1,700 ha of likely to involve land management condition. Sense of place upland heathland as well as activities that will improve other 2,267 ha designated smaller areas of a variety of services. This will be achieved Manage semi-natural woodlands, Regulating soil as SSSI other lowland woodland and principally through increase in particularly the area’s distinctive erosion grassland priority habitats. coverage of semi-natural habitat, clough and riverside woodlands. 347 local wildlife sites restoration of natural hydrological Regulating water The NCA contains 2 SACs, systems and sustainable grazing Renew the areas stock of mature flood quality Important habitats 1 SPA and 2,300 ha are regimes. These in turn have the plain, parkland and hedgerow trees. include herb-rich nationally designated as SSSI, potential to help increase regulating Climate regulation hay meadows and covering 3 per cent of the services such as regulation of water Conserve and restore semi-natural pastures, broadleaved NCA. quality and soil erosion, whilst also meadows. Regulating soil woodland, parkland contributing to sense of place. quality and waterbodies Maintain and where necessary restore blanket bog, wet heath and Regulating water other upland habitats where they are flow adversely affected by overgrazing, drainage, erosion. Or unsustainable Water availability burning practices. Pollination Maintain connectivity between habitats by protecting land in between pockets of habitat from intensification and maintaining the ability of species to move through the landscape.

54 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Principle services Assets/attributes: offered by main opportunities contributors Service to service State Main beneficiary Analysis Opportunities

Geodiversity 6 geological SSSIs There are currently 6 nationally National Designated sites provide Safeguard and maintain exposures in Geodiversity designated geological sites within important and accessible man-made quarries and cuttings. 25 Local Geological the NCA. These consist mainly sections allowing the Sense of place Sites of river sections and exposures interpretation, understanding Promote the geological heritage of along with the Clitheroe Knoll and continued research into the area. Sense of history Reefs SSSI, one of the best the geodiversity of the area. examples of knoll reefs in Exposure of these areas also Avoid afforestation where it could northern England. makes a positive contribution obscure landscape features of to sense of place and sense of particular conservation interest. 25 Local Geological Sites include history. examples of: river channels & sections, glacial and fluvioglacial landforms, disused quarries, ancient coal workings.

55 National Character 33. Bowland Fringe and Pendle Hill Area profile: Supporting documents

Photo credits Front cover: Looking west towards Langdon Beck, Winter © Natural England/Charlie Hedley Page 4: © Natural England/Jon Hickling Page 6: © Natural England/Rebecca Jackson-Pitt Page 8: © Natural England/Jon Hickling Page 9: © Natural England/Jon Hickling Page 10: © Natural England/Jon Hickling Page 13: © Charlie Hedley Page 31: © Natural England/Rebecca Jackson-Pitt

Natural England is here to secure a healthy natural environment for people to enjoy, where wildlife is protected and England’s traditional landscapes are safeguarded for future generations.

Catalogue Code: NE372

Should an alternative format of this publication be required, please contact our enquiries line for more information: 0845 600 3078 or email [email protected]

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This note/report/publication is published by Natural England under the Open Government Licence for public sector information. You are encouraged to use, and reuse, information subject to certain conditions. For details of the licence visit www.naturalengland.org.uk/copyright Natural England images are only available for non commercial purposes. If any other information such as maps or data cannot be used commercially this will be made clear within the note/report/publication. © Natural England 2012

56

National Character Area Profile: 35. Lancashire Valleys Key Facts and Data Source: Natural England

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NCA 35: Lancashire Valleys

Key Facts & Data

This document provides a correspond to national data. If summary of environmental data you have any questions about collected for the NCA. It is the Key Facts and Data, please intended to help guide anyone contact: making decisions that may [email protected] affect the local environment. .uk. Your feedback will help The information contained here shape the content of the full is collated from the best NCA profiles, which will be available national datasets. It is published from September recognised local information 2012 onwards. may provide additional detail and that this will not always

www.naturalengland.org.uk Map of Lancashire Valleys Total Area: 55,423 ha

The above map is provided from the Countryside Character Area description pending completion of NCA maps. It is recognised that the content of this map may now be out of date in some cases and is included for general reference only. New maps will include updated content and be provided within the full NCA profiles, due to be completed by 2013 1. Landscape and Nature Conservation Designations 5% of the NCA (2,700 ha) falls within the Forest of Bowland Area of Outstanding Natural Beauty AONB. The Forest of Bowland AONB Management Plan provides a policy framework and identifies a 5-year programme of actions (April 2009 - March 2014) to help guide the work of the AONB partnership organisations towards achieving the purpose of this plan - to conserve and enhance the natural and cultural beauty of the Forest of Bowland landscape.

The management plan can be downloaded at:

„ http://www.forestofbowland.com/cons_managementplan

Source: Natural England (2011)

1.1 Designated nature conservation sites The NCA includes the following statutory nature conservation designations:

Tier Designation Designated Area in Proportion Site(s) NCA of NCA International n/a n/a 0 ha 0% European Special n/a 0 ha 0% Protection Area (SPA) Special Area of n/a 0 ha 0% Conservation (SAC) National National Nature n/a 0 ha 0% Reserve (NNR) National Site of Special A total of 6 75 ha <1% Scientific sites wholly or Interest (SSSI) partly within the NCA Source: Natural England (2011)

Please Note: (i) Designated areas may overlap (ii) all figures are cut to Mean High Water Line, designations that span coastal areas/views below this line will not be included.

There are 275 Local sites in the Lancashire Valleys covering 3,228 ha which is 6 % of the NCA.

Source: Natural England (2011)

„ Details of individual Sites of Special Scientific Interest can be searched at: http://www.sssi.naturalengland.org.uk/Special/sssi/search.cfm „ Details of Local Nature Reserves (LNR) can be searched http://www.lnr.naturalengland.org.uk/Special/lnr/lnr_search.asp „ Maps showing locations of Statutory sites can be found at http://magic.defra.gov.uk/website/magic/ -select ‘Rural Designations Statutory’

1.1.1 Condition of designated sites

SSSI Condition Category Area in NCA Percentage of NCA SSSI Resource Unfavourable declining 0 ha 0% Favourable 71 ha 95% Unfavourable no change 0 ha 0% Unfavourable recovering 4 ha 5% Source: Natural England (March 2011)

„ Details of SSSI condition can be searched at: http://www.sssi.naturalengland.org.uk/Special/sssi/reportIndex.cf m 2. Landform, Geology & Soils

2.1 Elevation Elevation ranges within this NCA from 5 m above sea level to 486 m.

Source:Natural England 2010

2.2 Landform & Process The Lancashire Valleys are concentrated in a broad trough which runs north-eastwards from Chorley to Skipton, thus lying between the higher land of the Yorkshire Dales to the north, the Southern Pennines to the east and south, and the Forest of Bowland on the north and west sides. Pendle Hill, the outlier of Millstone Grit, forms part of the northern boundary of the area.

Source: Lancashire Valleys Countryside Character Area description

2.3 Bedrock Geology The Lancashire Valleys, with the key towns of Blackburn, Accrington and Burnley, occupy a broad trough underlain by Coal Measures. A millstone grit ridge lies between the Ribble and Calder catchments, this includes the Mellor Ridge and part of Pendle Hill. The main river, which is the Calder, cuts out of the trough through a gorge at Whalley and joins the river Ribble at the edge of the area to the north west of the town. The Millstone Grit outcrop of Pendle Hill, with its clear glaciated whaleback form, lies on the northern boundary of area.

Source: Lancashire Valleys Countryside Character Area description

2.4 Superficial Deposits The bottom of the trough containing Blackburn, Accrington and Burnley is covered in glacial deposits, mostly till. In the Feniscowles / Pleasington area west of Blackburn there are extensive sand deposits. The undulating lowland farmland and floodplain west of Blackburn is underlain by heavy boulder clays.

Source: Lancashire Valleys Countryside Character Area description

2.5 Designated Geological Sites

Designation Number of Sites

Geological Site of Special Scientific Interest 3 (SSSI) Mixed Interest SSSIs 0

There are 16 Local Geological Sites within the NCA

Source: Natural England (2011)

„ Details of individual Sites of Special Scientific Interest can be searched at http://www.sssi.naturalengland.org.uk/Special/sssi/search.cfm

2.6 Soils and Agricultural Land Classification

46% of the NCA is Grade 4 agricultural land. Poorer quality soils (Grade 5) occur in the higher areas to the east of Pendle Hill and around Foulridge, Kelbrook, Earby and Elslack, and better quality soils (Grade 3) occur along the Calder Valley and in the west of the NCA around the Ribble, Darwen and Yarrow rivers. There are 9 main soilscape types in this area: Slowly permeable seasonally wet acid loamy and clayey soils, covering 45% of the NCA; Slowly permeable seasonally wet slightly acid but base-rich loamy and clayey soils (14%); Slightly acid loamy and clayey soils with impeded drainage (10%); Slowly permeable wet very acid upland soils with a peaty surface (8%); Freely draining slightly acid loamy soils (8%); Freely draining slightly acid sandy soils (5%); Loamy and clayey floodplain soils with naturally high groundwater (3%); Very acid loamy upland soils with a wet peaty surface (3%); and Freely draining floodplain soils (2%).

Source:Natural England 2010

The main grades of agricultural land in the NCA are broken down as follows (as a proportion of total land area):

Agricultural Land Area in NCA Proportion of Classification NCA Grade 1 0 ha 0% Grade 2 55 ha <1% Grade 3 19,058 ha 34% Grade 4 25,290 ha 46% Grade 5 2,841 ha 5% Non-agricultural 0 ha 0% Urban 8,179 ha 15% Source: Natural England (2010) 3. Key Water Bodies & Catchments 3.1 Major Rivers/Canals The following major rivers/canals (by length) have been identified in this NCA.

River Name Length in NCA

River Calder 24 km River Ribble 23 km River Darwen 18 km Sabden Brook 10 km River Aire 9 km River Yarrow 9 km Source: Natural England (2010)

Please Note: other significant rivers (by volume) may also occur. These are not listed where the length within the NCA is short.

In addition the Leeds-Liverpool Canal runs through the NCA (78 km)

6 rivers flow through the NCA totalling 93.09 km along with the Leeds- Liverpool Canal (78 km).

The NCA contains part of the middle section of the River Ribble, which has its source in the Yorkshire Dales NCA, as well as the Ribble’s confluence with the River Hodder which drains the southern slopes of the Bowland Fells NCA. Tributaries of the Ribble within the NCA include the River Calder (and its tributary Sabden Brook) and the River Darwen. The River Yarrow rises on Rivington Moor in the Southern Pennines NCA and flows through the southern part of this NCA before joining the River Douglas in the Lancashire and Amounderness Plain NCA.

3.2 Water Quality The total area of Nitrate Vulnerable Zone is 35,791 ha (65%) of the NCA.

Source: Natural England (2010)

3.3 Protected Areas „ to be completed in consultation with the Environment Agency (full document only). 3.4 Water Framework Directive „ to be completed in consultation with the Environment Agency (full document only).

4. Trees and Woodlands 4.1 Total Woodland Cover The NCA contains 2,868 ha of woodland (5% of the total area), of which 894 ha is ancient woodland.

Source: Natural England (2010)

4.2 Distribution and size of woodland and trees in the landscape Small, often ancient, woodlands of oak, alder and sycamore extend along narrow, steep-sided cloughs on the valley sides, for example at Priestly Clough and Spurn Clough and in the Darwen valley. There are several small areas of conifer plantation the largest being at Standrise Plantation associated with Elslack reservoir. There are occasional fragments of former woodland along field boundaries particularly in the Ribble valley floodplain.

Source: Lancashire Valleys Countryside Character Area description

4.3 Woodland Types A statistical breakdown of the area and type of woodland found across the NCA is detailed below.

Area and proportion of different woodland types in the NCA (over 2 ha)

Woodland Type Area in NCA Proportion of NCA Broadleaved 1,900 ha 3%

Coniferous 269 ha <1%

Mixed 447 ha 1% Shrub / young trees 226 ha <1% Felled/land for prepared 25 ha <1% planting Source: Natural England (2010)

Area and proportion of Ancient Woodland and Planted Ancient Woodland within the NCA

Woodland Type Area in NCA Proportion of NCA Ancient semi-natural woodland 787 ha 1% Ancient re-planted woodland 107 ha <1% (PAWS) Source: Natural England (2004) 5. Boundary Features & Patterns 5.1 Boundary Features Boundaries are formed by hedges with few hedgerow trees, and by stone walls and post and wire fences at higher elevations. Boundaries are generally degraded around urban areas.

Source: Lancashire Valleys Countryside Character Area description; Countryside Quality Counts (2003)

5.2 Field Patterns The Ribble valley floodplain to the south and west is dominated by irregular, hedge bounded pasture fields dating from before 1600. These appear to have been created mainly through processes of assartment, leaving occasional fragments of former woodland along boundaries. To the north and east the dominant field forms are more planned and rectilinear reflecting episodes of moorland enclosure along the fringes of the Forest of Trawden and Pendle in the period 1600-1850. There are rare fragments of former strip-field agriculture alongside northern villages (Fowlridge, Kelbrook, Earby).

Source:English Heritage Historic Profiles; Countryside Character Area description; Countryside Quality Counts (2003) 6. Agriculture The following data has been taken from the Agricultural Census linked to this NCA.

6.1 Farm Type The predominant farm type in this NCA is livestock grazing. In 2009 there were 295 commercial livestock grazing holdings in the LFA (35%) and 121 in the lowlands (14%). There were also 131 dairy holdings (15%), 20 specialist poultry holdings (2%), 18 mixed holdings (2%), 12 horticultural holdings (1%), 11 specialist pig holdings (1%) and 6 cereals holdings (1%).Survey data from 2000 to 2009 shows 31% increase in the number of grazing farms in the LFA whilst grazing farms in the lowlands have decreased by 28%. Of the other holding types specialist pig holdings show an increase and all other types show a decrease in numbers.

Source: Agricultural Census, DEFRA (2010)

6.2 Farm Size Farm size distribution shows a slight skew towards the smaller size bands with most holdings (35%) being 5 – 20 ha. However, holdings over 50 ha account for 67% of the farmed area. Between 2000 and 2009 the number of commercial holdings decreased overall by 9% from 938 to 850. This decrease was across all size bands with the exception of farms over 100 ha which showed a 10% increase from 62 to 68 holdings.(Note: these figures do not include the access that many farmers have to common grazing on the moors).

Source: Agricultural Census, DEFRA (2010)

6.3 Farm Ownership 2009: Total farm area = 31,902 ha; owned land = 19,241 ha 2000: Total farm area = 31,735 ha; owned land = 20,669 ha. In 2009 60% of the total farm area was owner occupied. Between 2000 and 2009 there has been a slight increase in the total farmed area of 167 ha (1%) although there has been a slight decrease in the number of holders from 1,285 to 1,147.

Source: Agricultural Census, DEFRA (2010)

6.4 Land Use The main land use in this NCA is grass and uncropped land (96%), mainly for sheep and cattle rearing.

Source: Agricultural Census, DEFRA (2010)

6.5 Livestock Numbers Sheep are the most numerous livestock type in this landscape (a total of 118,100 in 2009 in comparison with 37,200 cattle and 2,900 pigs). Between 2000 and 2009 sheep numbers decreased by 19,100 (14%), cattle numbers decreased by 9,900 (21%) and pig numbers decreased by 3,200 (53%).

Source: Agricultural Census, DEFRA (2010)

6.6 Farm Labour In 2009 the majority of holdings are run by Principal Farmers (1,147 or 73%) with only 29 Salaried Managers (2%) being employed. Between 2000 and 2009 the total farm labour decreased by 9% from 1,735 to 1,573. The number of Principal farmers decreased from 1,285 to 1,147, Salaried Managers decreased from 32 to 29, FT workers decreased from 166 to 165, PT workers increased from 148 to 166 while Casual / Gang Workers decreased from 104 to 66.

Source: Agricultural Census, DEFRA (2010)

Please Note: (i) Some of the Census data is estimated by Defra so will not be accurate for every holding (ii) Data refers to Commercial Holdings only (iii) Data includes land outside of the NCA belonging to holdings whose centre point is within the NCA listed.

7. Key Habitats and Species

7.1 Habitat distribution / coverage The River Calder and its tributaries dominate this NCA. Canals, once the main transport routes for industry, are also a feature of the area. These waterways support valuable plant communities as well as populations of birds. The goosander, coot, grebes and warblers are all common here. Rare great crested newts and otters can also be found.

Fragmented agricultural land is dominated by pasture. Wet grasslands are common on the floodplains, and provide habitat for valuable populations of butterflies and birds. Snipe, curlew, redshank and lapwing are all common sights here. Species rich hay meadows are becoming less common with the application of modern agricultural techniques. The field boundaries are marked by hedgerows with few trees, while stone walls and fencing are characteristic on the higher ground.

Numerous large country houses with associated parkland are largely situated on the south facing valley sides away from major urban areas. Small woodlands occur throughout the farmland particularly on the sides of steep river valleys and cloughs. Wood anemone, herb Paris and small leaved lime can all be found here. Wet woodlands dominated by alder occur on the floodplains and river banks.

Source: Lancashire Valleys Countryside Agency Summary Statements; Lancashire Plains & Valleys Natural Area Profile

7.2 Biodiversity Action Plan (BAP) Priority habitats The NCA contains the following areas of mapped priority habitats (as mapped by National Inventories). Footnotes denote local/expert interpretation. This will be used to inform future national inventory updates.

UK BAP Priority Habitat Area in NCA Proportion of NCA Broadleaved mixed & yew 1,910 ha 3% woodland (Broad habitat) Upland heathland 615 ha 1% Coastal & floodplain grazing 552 ha 1% marsh Lowland meadows 381 ha 1% Lowland dry acid grassland 91 ha <1% Purple moor grass & rush 79 ha <1% pasture Upland calcareous grassland 71 ha <1% Blanket bog 53 ha <1% Lowland heathland 38 ha <1% Upland hay meadows 13 ha <1% Lowland calcareous grassland 11 ha <1% Source: Natural England (2011)

Maps showing locations of UK BAP Priority Habitats are available at „ http://magic.defra.gov.uk/website/magic/ select ‘Habitat Inventories’ 7.3 Key species and assemblages of species „ These are listed in Annex 1 (full document only) „ Maps showing locations of S41 species are available at http://data.nbn.org.uk/ 8. Settlement and Development Patterns 8.1 Settlement pattern Settlement within the Lancashire Valleys is extensive. There is a high proportion of built up land which includes the towns of Blackburn, Darwen, Accrington, Burnley, Nelson and Colne. There is substantial new industry in the area as well as many artefacts of the area’s industrial heritage. Scattered settlements on valley sides are comprised of older stone buildings, often of the Longhouse type, and isolated blocks of stone terraced houses perched at precarious angles on the steep slopes. There are also several large country houses along the Calder valley.

Source: Lancashire Valleys Countryside Character Area description; Countryside Quality Counts (2003)

8.2 Main Settlements The largest settlements within the NCA include: Blackburn; Burnley; Accrington; Chorley; Nelson; Colne; Skipton; Padiham; Oswaldtwistle; Great Harwood. There are also many towns, villages and hamlets with populations <10,000. The total estimated population for this NCA (derived from ONS 2001 census data) is: 671,807.

Source: Lancashire Valleys Countryside Character Area description; Countryside Quality Counts (2003)

8.3 Local vernacular & building materials Buildings are predominantly constructed from stone and are generally in good repair. The area’s many Victorian buildings and terraces are well- integrated into the landscape. There is a strong industrial heritage associated with the textile industry, and redundant mill buildings, mill lodges and ponds are common. Numerous large country houses with associated parklands occur, particularly on the northern valley sides away from major urban areas.

Source: Lancashire Valleys Countryside Character Area description; Countryside Quality Counts (2003) 9. Key Historic Sites & Features 9.1 Origin of historic features The history of the landscape is evident in its strong industrial heritage linked to the textile industry, with converted or redundant mill buildings, mill lodges and ponds, and the associated towns of Blackburn, Accrington and Burnley which expanded rapidly as a result of the industrial revolution. Some towns form part of earlier rural villages, retaining early buildings alongside stone terraces to accommodate textile workers. Evidence of older buildings, usually of sandstone grit, is also present in the scattered settlements on the valley sides. The historic character is also dominated by access and movement along the valleys, and is reflected in a Roman road and forts at Burwen Castle near Elslack and at Ribchester, and more recently by the Leeds- Liverpool Canal. Aspects of history likely to be particularly evident to the general public include the area’s country houses and associated parklands, located particularly on the northern valley sides. These include Read Park, Huntroyde Demesne and Gawthorpe, and Dunkenhalgh and Townley Halls, built as a result of the wealth from the textile industry.

Source: Countryside Quality Counts Draft Historic Profile, Countryside Character Area description 9.2 Designated Historic Assets

This NCA has the following historic designations:

„ 11 Registered Parks and Gardens covering 502 ha „ 0 Registered Battlefield/s covering 0 ha „ 34 Scheduled Monuments „ 1,323 Listed Buildings Source: Natural England (2010)

„ More information is available at the following address: http://www.english-heritage.org.uk/caring/heritage-at-risk/ „ http://www.english- heritage.org.uk/professional/protection/process/national-heritage- list-for-england/

10. Recreation and Access 10.1 Public Access 3% of the NCA 1,733 ha is classified as being publically accessible.This tends to be in the higher areas to the east of Pendle Hill and around Foulridge, Kelbrook, Earby and Elslack.

The table below shows the breakdown of land which is publically accessible in perpetuity:

Access Designation Area in NCA Proportion of NCA National Trust (Accessible all 0 ha 0% year) Common Land 313 ha 1% Country Parks 642 ha 1% CROW Access Land (Section 1,733 ha 3% 4 and 16) CROW Section 15 142 ha <1% Village Greens <1 ha <1%

Doorstep Greens 1 ha <1%

Forestry Commission Walkers 167 ha <1% Welcome Grants Local Nature Reserves (LNR) 80 ha <1% Millennium Greens 3 ha <1% Accessible National Nature 0 ha 0% Reserves (NNR) Agri-environment Scheme 8 ha <1% Access Woods for People 689 ha 1% Sources: Natural England (2011)

Please Note: Common Land refers to land included in the 1965 commons register; CROW = Countryside and Rights of Way Act 2000; OC and RCL = Open Country and Registered Common Land.

10.2 Rights of Way

There are 1,589 km of Public Rights of Way at a density of 2.9 km per km2. There are 2 National Trails within the NCA. 15 km of the Pennine Bridleway and 13 km of the Pennine Way fall within this NCA

Sources: Natural England (2010)

11. Experiential Qualities 11.1 Tranquillity Based on the CPRE map of Tranquillity (2006) lowest scores are along the M65 corridor, particularly around Blackburn, Accrington and Burnley.

A breakdown of tranquillity values for this NCA are detailed in the table below: Tranquillity Tranquillity Score

Highest Value within NCA 48 Lowest Value within NCA 91 Mean Value within NCA 16 Sources: CPRE (2006)

„ More information is available at the following address: http://www.cpre.org.uk/what-we-do/countryside/tranquil- places/in-depth/item/1688-how-we-mapped-tranquillity 11.2 Intrusion

The 2007 Intrusion Map (CPRE) shows the extent to which rural landscapes are ‘intruded on’ from urban development, noise (primarily traffic noise), and other sources of visual and auditory intrusion. This shows that the majority of the NCA is categorised as disturbed. The largest remaining undisturbed areas include pockets to the south of Longridge Fell and Pendle Hill, land to the south of Skipton and very small areas to the west of Blackburn. A breakdown of intrusion values for this NCA are detailed in the table below.

Intrusion 1960s 1990s 2007 Percentage Category change (1960s- 2007) Disturbed 52% 64% 67% 15% Undisturbed 38% 26% 16% -21% Urban 10% 10% 17% 7% Sources: CPRE (2007)

Notable trends from the 1960s to 2007 are a general increase in intrusion outwards from the urban centres

„ More information is available at the following address: http://www.cpre.org.uk/resources/countryside/tranquil-places

12 Data Sources

„ Lancashire Plains and Valleys Natural Area Profile, Natural England (English Nature 1997) „ Lancashire Valleys Countryside Character Description, Natural England (Countryside Commission/Countryside Agency 1998/1999) „ Countryside Quality Counts, Natural England (Countryside Agency 2003) „ Agricultural Census June Survey 20002009, Defra (2010) „ Intrusion Map, CPRE (2007) „ Tranquillity Map, CPRE (2006) „ Draft Historic Profiles, English Heritage (2004)* „ For further information on Natural England data sources please see the Key facts and data interpretation note

Please note all figures contained within the report have been rounded to the nearest unit. For this reason proportion figures will not (in all) cases add up to 100%. The convention <1 has been used to denote values less than a whole unit. Photo Credits

Front Cover: View across Roeburn Valley (c) Natural England (Countryside Agency)

V1.0

Photography and Photomontage in Landscape and Visual Impact Assessment – Advice Note 01/11 Source: Landscape Institute

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Photography and photomontage in landscape and visual impact assessment

Landscape Institute Advice Note 01/11 Contents

1.0 Purpose and background

2.0 Current guidance

3.0 Principles of photography and photomontage 3.1 Objectives 3.2 Criteria for photomontages 3.3 Viewpoint selection 3.4 Field of view

4.0 Photography 4.1 Cameras 4.2 Lenses 4.3 Setting up and recording data

5.0 Printing and viewing images 5.1 Producing the photomontage 5.2 Producing photomontages

6.0 Summary

References

Technical appendix: Digital photography

Advice 01/11 Landscape Institute Photography and photomontage Page 1 in landscape and visual impact assessment 1.0 2.0 Purpose and Current guidance background

The purpose of this Advice Note is — This Advice Note supersedes LI to provide advice to the landscape Advice Note 01/09. The LI’s guidance professional on photography and on photography and photomontage photomontage methods in landscape in landscape and visual impact and visual impact assessment. It does assessment in Appendix 9 of not consider the use of photography or Guidelines for Landscape and Visual photomontage for other purposes, such Impact Assessment 2nd ed (2002) as promoting or exhibiting a scheme. remains relevant.

Photographs and photomontages often — Scottish Natural Heritage’s Visual form an important part of planning representation of windfarms: good applications and Environmental practice guidance states that the Statements, in which the preparation and guidance may also be applicable to presentation of reliable visual information other forms of development or within is integral to the assessment of landscape other locations (SNH 2006, para 15). and visual impacts. Photographs and The LI endorses this guidance and photomontages are technical documents strongly advises members to follow in this context, and should be produced this where applicable in preference to and used in a technically appropriate any other guidance or methodology. manner. — When regulatory authorities It is essential to recognise that: specify their own photographic — Two-dimensional photographic and photomontage requirements, images and photomontages alone the landscape professional should cannot capture or reflect the complexity carefully consider whether they are underlying the visual experience, justified, or whether they would and should therefore be considered under- or over-represent likely an approximation of the three- effects, in the professional’s opinion. dimensional visual experiences that Consideration may then be given an observer would receive in the field; to adding images to the impact assessment, or omitting them, and — As part of a technical process, explaining the reasons for doing so. impact assessment and considered judgements using photographs and/or photomontages can only be reached by way of a visit to the location from which the photographs were taken.

This Advice Note was prepared by members of the Landscape Institute (LI) Technical Committee, in consultation with LI members and technical experts experienced in photography, photomontage and landscape and visual impact assessment. It will be reviewed and updated as necessary to reflect the rapid pace of change in digital photography and related technologies.

Advice 01/11 Landscape Institute Photography and photomontage Page 2 in landscape and visual impact assessment 3.0 Principles of photography and photomontage

3.1 Objectives 3.2 Criteria for photomontages 3.4 Field of view The overall aim of photography and Photomontages use photographs of an The most appropriate combination photomontage is to represent the actual scene modified by the insertion of lens, camera format and final landscape context under consideration of an accurate representation of the presentation of image should be and the proposed development, both as visible changes brought about by the deployed to represent the relevant accurately as is practical. proposed development. They are subject landscape. This is likely to include both to the same inherent limitations as the site of the proposed scheme and its The objective of photography for visual photographs, for example only showing context, so that a scheme’s appearance and landscape impact assessment the scene as it would appear under the and its place within its environment can is to produce printed images of a size same conditions that prevailed when be recognised and understood. The and resolution sufficient to match the the original photograph was captured. proposal under consideration and its perspective and, as far as possible, the A properly constructed photomontage relevant landscape context will determine detail in the same view in the field (SNH can serve as a useful means of indicating the horizontal field of view required for 2006, para C12-21) and which can also the potential visual effect of a future photography and photomontage from serve as an accurate aide-memoire once development, however. any given viewpoint. This will in turn the observer has left the field. determine whether a single-frame image The LI recommends that for landscape will suffice or whether a panorama will be The objective of a photomontage is and visual impact assessment purposes required. to simulate the likely visual changes a photomontage should: that would result from a proposed While a standard lens giving a horizontal development, and to produce printed — be reproduced at a size and level of field of view of about 40 degrees may images of a size and resolution sufficient geometric accuracy to permit impact be suitable for some purposes, a single- to match the perspective in the same view assessment, which must include frame photograph based on this field of in the field. inspection at the location where the view is unlikely to convey the breadth of photograph was taken; visual information required to represent — be based on a replicable, transparent a proposed development and relevant and structured process, so that the context. If the required field of view is accuracy of the representation can be only slightly greater than 40 degrees, a verified, and trust established; wide-angle lens or wide-angle setting — use techniques, with appropriate on a zoom lens may be appropriate. explanation, that in the opinion of the Where it is much greater than 40 degrees, landscape professional best represent a panoramic image produced by the the scheme under consideration and careful ‘stitching’ together of single- its proposed environment accurately frame images, or the use of a suitable true as possible; panoramic camera, can provide a more — be easily understood, and usable by informative representation of the effect members of the public and those with of a development in the landscape (SNH a non-technical background; 2006, Technical Appendix B). — be based on a good quality photographic image taken in The horizontal field of view is usually representative weather conditions more relevant to representations of rural and peri-urban landscapes. The vertical 3.3 Viewpoint selection field of view may be more important in The landscape professional should urban landscapes, however, in which select a set of photographic viewpoints case it may be necessary to use a wide- which are considered representative angle lens or wide-angle setting on a of the range of likely effects, viewing zoom lens. The camera may be used in experiences and viewers, ensuring that portrait orientation for panoramic as well none are under- or over-represented. as single-frame images. Viewpoints should be agreed with the regulatory authority or authorities where possible, and with other parties as considered necessary.

Advice 01/11 Landscape Institute Photography and photomontage Page 3 in landscape and visual impact assessment 4.0 Photography

4.1 Cameras 4.2 Lenses 4.3 Setting up and recording data A good quality camera and lens The use of 35mm film and a 50mm focal Wherever possible, cameras should be are essential to the production of length standard lens as a reference tripod mounted and levelled in horizontal photographs and photomontages for standard, while still valid, is now and vertical axes. Where it has been landscape and visual impact assessment somewhat outdated. That combination necessary to raise or lower the horizon work. Many good quality digital cameras of lens and film gives a horizontal field of line by cropping, this should be stated. are suitable, but it is essential to consider view of a little under 40 degrees. the whole process from field procedure It is recommended that the following to post-processing to printing in order Use of a fixed focal length lens ensures data is recorded: to choose equipment which will give that the image parameters of every — Camera, lens focal length and results of the accuracy required. photograph are the same, simplifies the horizontal field of view construction of panoramas, and ensures — Date, time, weather, lighting A camera with a fairly high resolution compatibility of photography for all conditions and direction of view will be required to produce sufficiently viewpoints. Fixed focal length lenses are — The viewpoint’s height above ground good-quality images to be reproduced at often either unavailable or prohibitively level and OS grid coordinates the size required: a 12 megapixel sensor expensive for many digital cameras is usually sufficient. This resolution however. outperforms 35mm colour print film in terms of both image resolution and It is usually impossible to set a zoom lens graininess. The lens used must be of a to a specific focal length, apart from the sufficiently high optical quality to take longest and shortest ends of its focal advantage of the sensor’s resolution. length range. The zoom setting and focal length are recorded in the image Change in all aspects of photography metadata (EXIF data) stored with each and photomontage have taken place image, however. The horizontal field of over the last ten years. 35mm colour view for a given zoom lens setting can film and the associated cameras and be calculated from the focal length and lenses have been almost completely the camera’s sensor size (see Technical supplanted by digital cameras; digital Appendix for details). Theoretically image processing is now a fundamental zoom lenses are always of inferior optical element of photography, both within quality to fixed focal length lenses, the firmware of the camera and as a but the difference is not significant in subsequent operation on a computer, modern lens design. and printing has become wholly digital, using a wide variety of devices offering When a wide-angle lens or zoom lens different qualities of output. Future at a wide-angle setting is used, a higher changes will undoubtedly further camera resolution may be required change the parameters for landscape in order to obtain the same resolution photography. in the finished image than would be needed for a ‘standard’ setting and an approximately 40 degree field of view (see Technical Appendix for details).

Use of a telephoto lens, or enlargement of part of a larger image, either single- frame or panoramic, may be necessary to show detail that is too small to be displayed at the correct viewing distance for the image as a whole. The purpose of the additional image should be explained when this is done.

Advice 01/11 Landscape Institute Photography and photomontage Page 4 in landscape and visual impact assessment 5.0 Preparing and viewing images

5.1 Producing photomontages 5.2 Viewing distance provided from the same viewpoint. A digital photomontage consists of a Given that the objectives of photography The ‘before’ photograph and the ‘after’ base photograph composited digitally and photomontage are to produce photomontage should be presented on with a computer-rendered image of printed images of a size and resolution the same page and/or at the same scale the proposal under consideration. This sufficient for use in assessment work in to allow comparison if practicable. compositing process will typically the field, the exact dimensions of these include digitally manipulating the images will depend on the characteristics masking of the proposed development of the view under consideration. by foreground features and may also involve digitally removing existing All photographs, whether printed or features such as trees. The compositing digitally displayed, have a unique, necessarily demands a level of digital correct viewing distance - that is, the manipulation and visual skill and distance at which the perspective in judgement on the part of the person the photograph correctly reconstructs carrying it out. the perspective seen from the point at which the photograph was taken (SNH It is critical that the scale of the proposal 2006, para A18-25). The correct viewing and its location within the scene depicted distance should be stated for all printed in the photograph are accurately or digitally displayed photographs and represented. In order to achieve this, it photomontages, together with the size is necessary to match the perspective at which they should be printed. All parameters of the photograph photographs and photomontages used accurately, to record viewpoint location in a document should have the same and camera settings, and to use viewing distance whenever possible. rendering software correctly (SNH 2006, para 209ff). The viewing distance for hand-held photographs and photomontages Explanatory text should be provided should be between 300mm and 500mm to describe the procedure used to fit (SNH 2006, para 126). The viewing the rendered image to the underlying distance and the horizontal field of view photographic view. The accuracy together determine the overall printed of a photomontage may usefully be image size. illustrated by means of a wireline image incorporating sufficient topographic or Photographs and photomontages other features to allow a comparison to should be printed or published digitally be made between the wireline and the at an appropriate scale for comfortable photograph. viewing at the correct distance, noting the limitations of the printing process It should be borne in mind when particularly with regards to colour preparing images that inkjet printing, and resolution. Guidance should be laser printing and digital press provided on viewing the image in order technologies all have different colour to best represent how the proposal rendition and resolution issues. A would appear if constructed, such as minimum resolution of 300 pixels per the required viewing distance between inch will generally be required for high- the eye and the printed image, and an quality printing (see Technical Appendix). indication of whether the image is a The image size and resolution together single-frame or panorama. Panoramic determine the number of pixels required images should be curved so that to be captured by the camera. peripheral parts of the image are viewed at the same intended viewing distance, or viewed by panning across a flat image with the eye remaining at the recommended viewing distance (SNH 2006, para B20). It is important to indicate the correct viewing distance for single-frame or panoramic images to allow consistent comparison between different image formats

Advice 01/11 Landscape Institute Photography and photomontage Page 5 in landscape and visual impact assessment 6.0 References Summary

The selection of an appropriate Landscape Institute and IEMA combination of camera, lens and printing (2002) Guidelines for landscape and technology requires informed technical visual impact assessment (2nd ed). decision-making. Other aspects of London: Spon. photography and photomontage such as choice of view, post-processing, and Scottish Natural Heritage (2006) Visual presentation of the final images are a representation of windfarms: good matter of professional judgement. practice guidance. Inverness: Scottish Natural Heritage. SNH report no. FO3 AA A suitable digital camera for 308/2 environmental impact assessment work will need to have a fairly high resolution sensor, good quality lenses, and manual focus and exposure settings. Most digital SLRs and some non-SLRs are likely to be suitable. The quality of the printing process is critical in producing finished images which successfully reproduce the digital data captured by the camera. As much care and consideration should be applied to the selection of a print process as to the selection of a camera.

Landscape Institute Technical Committee February 2011

Advice 01/11 Landscape Institute Photography and photomontage Page 6 in landscape and visual impact assessment Technical appendix: Digital photography

This appendix provides technical background At greater viewing distances, larger pixels may multiplication is a good enough estimate, especially information on digital photography relevant to be used and still be too small for the eye to resolve as it is guaranteed to be an overestimate. landscape and visual impact assessment work, individually. For 400mm viewing distance, the If the lens used has a horizontal field of view of as little detailed advice is available on this subject. minimum resolution is 225 PPI and for 500mm 39.6 degrees equivalent to a 50mm lens on a 35mm This appendix should be read in conjunction with viewing distance, it is 180 PPI. camera (Table A1), then for 300mm viewing distance the Technical Appendices in the SNH guidance Note that pixels per inch, PPI, is not the same printing, the required image width in the camera is Visual representation of windfarms: good practice as the dots per inch, DPI, usually used to describe 61.8 x 39.6 = 2448 pixels rounding up to the nearest guidance, referenced below by the relevant printer resolution. Each pixel in a photographic pixel, which is about equivalent to a 4.5 megapixel paragraph number in brackets. image consists of 256 levels of brightness in each image. For 500mm viewing distance, the required of red, green and blue, giving 16,777,216 possible image width is 103.1 x 39.6 = 4083 pixels, equivalent Focal length and field of view different colours and this is what is displayed on a to about 12.5 megapixels. As with any camera, a digital camera’s horizontal monitor. Most printers can only lay down dots of If it is necessar y to use a wide-angle lens or wide- field of view is determined by the focal length of the pure primary colours of ink or toner, depending on angle zoom setting, rather higher numbers will lens and the size of the sensor (A26-28). The formula technology. Many printers can deliver variable ink result. If the lens has a field of view of 65.5 degrees given in (A27) provides a method of calculating the drop sizes and many have more than the minimum equivalent to a 28mm lens on a 50mm camera (Table field of view. of four primary colours of ink available, but each A1), then for 300mm viewing distance, the required The sensor size will usually be stated in the printed dot is still limited to far fewer colours than image width will be 61.8 x 65.5 = 4048 pixels, documentation supplied with a digital camera, but the number required to reproduce the contents of equivalent to about 12.3 megapixels. For 500mm may not be specified in millimetres. For example, a pixel. The technical solution to this is to lay down viewing distance, this becomes 103.1 x 65.5 = 6754 the commonly used 23.7 x 15.7mm size may be many very small dots to represent each image pixel. pixels, equivalent to about 34.2 megapixels. expressed as 1.8″ or as APS-C. It may require some For this reason, the printer resolution required to For most purposes, a 12 megapixel camera will online research to discover the actual dimensions. deliver a 300 PPI image may be as high as 2400 DPI produce images with detail at the limit of the print For a fixed focal length lens, the focal length depending on the printer technology used. technology used to reproduce them. If however, it will usually be marked somewhere on the lens It may in practice be difficult to achieve 300 PPI is necessary to print material for 500mm viewing barrel. A zoom lens will generally have the range of printing, which may lead to a decision either to distance based on original photographs taken focal lengths marked on it. To determine the focal accept a lower print quality or to use a viewing with a very wide-angle lens, then either a very high length used for an image taken using a zoom lens, distance greater than 300mm. specification camera will be needed or a slightly it is necessary to refer to the EXIF metadata stored It is important to understand the limitations of lower image quality may have to be accepted. with the image. Lens focal length is one of the fields the print process chosen, whether the printing is For comparison, it should be borne in mind that of information usually stored in the EXIF data. being done in-house or by an external print bureau. 35mm film has a resolving power about equivalent This value needs to be known to at least one and It will probably be necessary to print some test to a 9 megapixel digital sensor; a 12 megapixel preferably two decimal places in order to calculate images to check the print quality. camera will potentially capture far more detail the field of view accurately. Different cameras store than was ever possible with film. Also note that this information to dif ferent degrees of numerical Calculating the required camera resolution while 300 PPI print resolution is essential at 300mm precision. Software also varies in the number of Having decided the image resolution required to viewing distance, 225 PPI will produce the same decimal places it shows for the focal length value. print images at the sizes recommended in the 2006 ef fect at 400mm viewing distance and 180 PPI at Some models of digital camera have been found SNH Good Practice Guidance, it is possible to to 500mm, although it will look a little ‘blocky’ on the to store inaccurate information in the EXIF data. It arrive at the minimum camera resolution needed to page until held at the correct distance. is prudent to take advice on this before purchasing achieve that. a camera. Printed image size is defined by horizontal Choice of lenses field of view and correct viewing distance (D2). It As noted in the SNH guidance, the main issue in the 35mm equivalent focal length therefore follows that the horizontal scale of an choice of lens focal length is the balance between The focal length of lenses on digital cameras is image, which may be expressed in millimetres detail captured and field of view (D7); there is no sometimes expressed in terms of the ‘35mm per degree of field of view, is determined solely by single best focal length that works best under all equivalent focal length’. This value is what the focal the correct viewing distance. For example, a 360 circumstances. length of a lens on a 35mm film camera would degree panorama with a correct viewing distance of Irrespective of the focal length of a lens, its be with the same horizontal field of view as the 300mm is 1885mm wide; see (B22-29) for formulae. optical quality is of paramount importance. Many camera and lens combination under discussion. The image scale will therefore be 5.24mm per digital cameras offer very high resolutions in For example a lens with a focal length of 32.9mm degree. For a panorama with a viewing distance of terms of megapixels. However, it is the case with on camera with a sensor 23.7mm wide would have 500mm, the scale is 8.73mm per degree. some cameras, particularly cheaper ones, that a horizontal field of view of about 39.6 degrees, A panoramic image has a constant horizontal the resolving power of the supplied lens does not the same as a 50mm lens on a 35mm film camera. scale, so the millimetres per degree calculated justify the installed sensor resolution. The fact is that A 32.9mm focal length lens in this context might above, will be correct across the whole width of digital sensors and memory chips are quite cheap therefore be described as a 50mm equivalent lens. the image. A single-frame image, however, has a components whereas good lenses are relatively The 35mm equivalent focal length is one of scale increasing radially from the centre. The values expensive. the fields of information stored in the EXIF data of calculated above will therefore only be correct at There is no simple way of judging the quality of a a digital image but unfortunately not all cameras the centre of a single-frame image and will increase camera lens; however, an informed choice can often store this information and those that do round it to towards the sides of the frame; see (A11-13) and be made based on in-depth independent technical the nearest millimetre of focal length, which is not (B17-18). reviews many are available on-line and a study of suf ficiently precise for field of view calculations. At 300 PPI print resolution, these calculated sample images. scales correspond to 61.8 pixels per degree for Print resolution 300mm viewing distance and 103.1 pixels per Given that the objective is to produce a printed degree for 500mm viewing distance. image, the required print resolution is the starting These resolutions are therefore the minimum point for calculating the required camera resolution. angular resolution that it is desirable to capture in This appendix therefore addresses these issues in the original digital image in the camera for eventual the order that they should be considered. use at 300mm and 500mm viewing distances. The limit of acuity ability to resolve detail of It is not mathematically correct simply to the human eye is about 1 minute of arc (C1). At a multiply the pixels per degree resolution by the field viewing distance of 300mm, this equates to a spatial of view of the lens to obtain the required number of dimension of 1/291 inch. A good target resolution pixels across the image. The true value will always for printing is therefore 300 pixels per inch PPI giving be less than a simple multiplication. However, as a pixel size of 1/300 inch for images to be viewed at this calculation is simply a way of checking that 300mm viewing distance. enough image detail is being captured, a simple

Advice 01/11 Landscape Institute Photography and photomontage Page 7 in landscape and visual impact assessment Technical appendix: Digital photography

Camera settings Autofocus: Many passive autofocus systems are Image format: All digital cameras offer a range of Most digital cameras come with a plethora sensitive to the presence of foreground objects formats in which the image will be stored on of automatic settings designed to make the and can result in the focus being at less than the camera’s memory card. Typically these will photographer’s task easier. Some of these should be infinity. More seriously, the focus can be slightly be JPEG at a variety of quality settings, camera disabled or treated with caution while undertaking dif ferent in successive frames of a panoramas, ‘raw’ and on some cameras, but increasingly photography for landscape and visual impact potentially precluding a clean splice. Autofocus supported Adobe DNG digital negative format. assessment. should be switched off and the lens manually Raw and DNG both serve the same function focussed on infinity (E8-9). Note also, that as of storing the contents of the sensor unaltered focussing involves physically shif ting the lens hence ‘raw’ together with a series of parameters back and forth along its axis, focussing other recording the camera’s current settings. Thus than on infinity will change the principal distance post processing stages, such as white balance of that image (A21-22). and sharpening are recorded as parameters but not actually applied to the image. Raw and DNG Digital zoom: Many inexpensive digital cameras provide the user with the maximum possible of fer both ‘optical zoom’ and ‘digital zoom’. opportunity to get the best quality out of the ‘Optical zoom’, as the name implies, uses the image. Their disadvantage is that the image sizes optics of a zoom lens to enlarge the image will be 2-6 times as large as JPEG equivalents, projected onto the sensor. ‘Digital zoom’ is a requiring more storage space on memory simple enlargement of the digital image and cards and computers and also requiring more adds no information. ‘Digital zoom’ should never time and effort to post-process. Unless there be used in photography for landscape and visual is a compelling reason to use raw or DNG, the impact assessment. highest-quality JPEG format usually provides sufficient image quality. Some cameras provide Automatic exposure: Automatic exposure greatly the option of automatically storing both raw speeds opportunistic photography, but rarely and JPEG, which allows the choice of format results in optimum results for landscape and to be made on an image by image basis but of visual impact assessment work. Manually course requires even more storage space than setting an aperture of about f/5.6 or f/8 will raw alone. usually yield the sharpest possible photographs (E11). The ISO setting for the sensor should generally be set to 400 or less to limit image noise. Some cameras have a special panoramic setting which enables the shutter speed, aperture and ISO setting of the first frame to be maintained for successive frames. If that facility is available, then it may be possible to use an aperture-priority automatic mode, otherwise it is safer to meter a typical frame in the panorama and then set the exposure manually (E10).

Automatic white balance: Many digital cameras have a facility to automatically compensate for ambient colour temperature, so that, for example, photographs taken under indoor lighting do not appear yellow compared with those taken in daylight. This facility can have unforeseen consequences when taking panoramas. For example, the presence of a red telephone box in the foreground of one frame may result in a cyan cast on the colour in that frame only. White balance should be set manually to daylight.

Image sharpening: Many digital cameras have a facility to sharpen the photographic image in the camera. This option should be switched of f. Compositing a photomontage is much more difficult to do satisfactorily if the base image has already been sharpened, par ticularly if it is over- sharpened. Any image sharpening required for printing can be done in a more controlled manner in image processing sof tware.

Advice 01/11 Landscape Institute Photography and photomontage Page 8 in landscape and visual impact assessment Landscape Institute Inspiring great places

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Visual Representation of Windfarms – Good Practice Guidance 29th March 2006 Source: Prepared by Horner & Maclennan and Envision for Scottish Natural Heritage, The Scottish Renewables Forum and the Scottish Society of Directors of Planning

k:\projects\ua005852-mitton road appeal site, whalley\f-reports\title - scottish.docx Page 1

Visual Representation of Windfarms

Good Practice Guidance

29 March 2006

Prepared for Scottish Natural Heritage, The Scottish Renewables Forum and the Scottish Society of Directors of Planning

by

horner + maclennan & Envision 1 Dochfour Business Centre 21 Lansdowne Crescent Dochgarroch Edinburgh Inverness EH12 5EH IV3 8GY T: 0131 535 1144 T: 01463 861460 F: 0131 535 1145 F: 01463 861452 E: [email protected] E: [email protected]

SNH COMMISSIONED REPORT

Summary

VISUAL REPRESENTATION OF WINDFARMS GOOD PRACTICE GUIDANCE Report No: FO3 AA 308/2 Contractor: horner + maclennan and Envision

BACKGROUND This guidance is derived from research reported within the publication Visual Assessment of Windfarms: Best Practice, by the University of Newcastle (2002). The sections of this original work concerning visibility maps, viewpoints and visualisations have been updated and refined through a review of current VIA practice, current illustrative methods, consultation with stakeholders and reference to other guidance documents.

The production and use of visual representations forms just one part of the Visual Impact Assessment (VIA) of proposed windfarm developments and, in turn, this forms just one part of the wider Landscape and Visual Impact Assessment within an Environmental Impact Assessment. Yet within the visual analysis process itself, there is a wide range of different tools and techniques that can be used. This Good Practice Guidance advises on the different purposes, uses and limitations of these and sets down some minimum technical requirements.

MAIN FINDINGS

• Visibility maps and visualisations are tools for VIA. They help the landscape architect or experienced specialist assessor to identify and assess potential significant visual impacts, and help the wider audience of an Environmental Statement to understand the nature of these visual impacts through illustration.

• Various software is available to produce visibility maps and visualisations of windfarms. These possess different strengths and weaknesses. In this respect, minimum standards can be defined; however there is no ‘one size fits all’ solution.

• The choice of visibility mapping and visualisations forming part of a VIA should be based on why they are being produced, how they are to be used, and what information they can provide. This decision should occur in an informed and methodical manner, in consultation with the determining authority and consultees. This process, including the technical specification of visualisations, should also be clearly documented within the ES.

• Different people read visibility maps and visualisations in different ways. This is partly based on their experience and understanding of landscapes and the typical visual impacts of windfarms, and partly from their experience and understanding of how visualisations compare to how a development actually looks once built.

• New method of visibility mapping and visualisations will continue to develop, as will other approaches not included within the scope of this study, such as the use of computer animation and the representation of cumulative impacts. Consequently, it is envisaged that the content of this Good Practice Guidance will require future updating.

For further information on this project contact: Frances Thin, SNH Inverness. [email protected] For further information on the SNH Research & Technical Support Programme contact: snh.org.uk/research

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ACKNOWLEDGEMENTS

The production of this publication has been directed by the following Steering Group:

Rob Forrest Scottish Renewables Forum Jason Ormiston Scottish Renewables Forum Ted Leeming Natural Power Consultants Julie McAndrew Scottish Natural Heritage Frazer McNaughton Scottish Natural Heritage Jenny Simmonds Scottish Natural Heritage Nigel Buchan Scottish Natural Heritage Kay Hawkins E4environment Ltd Phil Marsh spatial data analyst John Rennilson Scottish Society of Directors of Planning

In addition, many planners, landscape consultants and windfarm developers participated in the development of this project through contribution to a series of workshops held in September 2004.

Natural Power and Green Power are acknowledged for giving permission to use some of their photography and ES material, and to base hypothetical visualisations on some of their windfarm site data.

This publication builds upon the original findings of the SNH research report - 'Visual Assessment of Windfarms: Best Practice', produced by the University of Newcastle in 2002. It was initially led and developed by John Benson of the University of Newcastle, until John's sudden and extremely sad death in March 2004.

John Benson was a well-respected researcher and consultant at the forefront of this work. He had the ability to see all sides of an issue with great clarity, fair-mindedness and understanding and was a great mentor to all that worked with him. It is hoped that the fruition of this work does his reputation justice. The draft report was developed by John and his colleagues at the University of Newcastle, Karen Scott and Maggie Roe; and then, from December 2004, this work was completed by horner + maclennan and Envision.

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CONTENTS page 1 Introduction 9 Aims and Objectives. What, who and how to use the Good Practice Guidance.

2 Zone of Theoretical Visibility 23 Data, preparation and presentation

3 Viewpoints 53 Selection and use of viewpoints and the recording of information

4 Visualisations 69 Which to use and when. Photography, wirelines, photomontages, other techniques, and their presentation

5 Conclusions 143

Appendices i Bibliography ii Glossary iii Acronyms and abbreviations

Technical appendices A Camera perspective B Panoramic photography C Human vision D Choice of focal length E Taking good photographs F Earth curvature and refraction of light

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List of figures

1 The aims of the Good Practice Guidance

2 Structure of the report

3 Existing guidance relevant to the LVIA of windfarms

4 Comparison of Digital Terrain Models

5 Comparison of ZTV grid size

6 The effects of earth curvature upon a ZTV

7 Process of determining ZTV extent

8a+b Measuring the extent of a ZTV

9a+b Presentation of ZTV information

10a+b Comparison of ZTV base map reproduction

11 Overlap of A3 sheets to illustrate ZTV coverage

12a,b+c Comparison of ZTV base map colouring

13a+b Single and multiple colour overlay on ZTV

14 Colour blindness

15 The effect of colour choice on ZTV clarity for colour blind people

16 Positioning of distracting/ screening features within a photograph

17 Photograph of view pre-development, as predicted by a photomontage, and at present after windfarm construction

18 The relationship between image size, viewing distance and the ‘real life view’

19 Comparison of single frame and panorama

20 Image size is directly proportional to focal length

21 Photographs of same subject taken with alternative lens length

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22a Photograph of existing windfarm using 28mm focal lens

22b Photograph of existing windfarm using 50mm focal lens

22c Photograph of existing windfarm using 135mm focal lens

23 Variable direction of wind turbines

24 Various levels of image sharpening

25 The effect of colour balancing an image

26 Panorama and planar perspectives

27 The effect of earth curvature on wireline composition

28a+b Comparison of wireline DTM representation and colour

29a+b Representation of land use change (in addition to wind turbines) using photomontage

30 Superimposition of wireline upon photograph

31 Coloured rendering to illustrate forestry works

32 Diagrammatic sketch of a landscape

33 Free-hand sketch of a landscape

34 The triple arrangement of visualisations

35 Use of a comfortable viewing distance

36 A visualisation mounted on a board on site

37 Process of choosing visualisations for each individual viewpoint

38 Diagrammatic comparison of visualisation layouts

39 Triple visualisation combination at A3 (not recommended). Photograph, wireline and photomontage

40 Triple visualisation combination at A1. Photograph, wireline and photomontage

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41a+b Minimum requirement (not recommended) combination of photograph and wireline

42a Recommended image height, although unadvised separation of photograph and wireline. Photograph of existing view (1of 3)

42b Recommended image height, although unadvised separation of photograph and wireline. Wireline (2of 3)

42c Recommended image height. Photomontage (3 of 3)

43a Minimum requirement (image size and viewing distance) combination of photograph, wireline and photomontage presenting horizontal field of view of 110° on A2 width image (1 of 2)

43b Minimum requirement (image size and viewing distance) combination of photograph, wireline and photomontage presenting horizontal field of view of 110° on A2 width image (2 of 2)

44a Recommended image size and viewing distance combination of photograph, wireline and photomontage presenting horizontal field of view of 94° on A1 paper (1 of 2)

44b Recommended image size and viewing distance combination of photograph, wireline and photomontage presenting horizontal field of view of 94° on A1 paper (2 of 2)

45 Binding of oversize sheets within a report

46a Presentation of visualisation on high gloss paper

46b Presentation of visualisation on coated paper

46c Presentation of visualisation on standard copy paper

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List of tables

1 Uses and limitations of ZTVs 2 Recommended distance of ZTV 3 Size of ZTV at various scales and to fit standard paper sizes 4 Information on ZTV production to be provided 5 Good Practice Guidance Summary: Zone of Theoretical Visibility 6 Uses and limitations of viewpoints 7 Views and viewers to be represented through choice of viewpoints 8 Viewpoint information to be recorded 9 Good Practice Guidance Summary: Viewpoints 10 Uses and limitations of visualisations 11 Best weather and lighting for photographing turbines 12 Information to be recorded at each photograph location 13 Use of visualisations within VIA 14 Size of paper required to accommodate specific horizontal field of view, image size and viewing distance. 15 Comparison of advantages and disadvantages for different visualisation combinations 16 Information to accompany visualisations 17 Good Practice Guidance Summary: Visualisations A1 Focal lengths and fields of view F1 Height corrections for earth curvature and refraction

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1 Introduction

1 ‘Pictures speak louder than words’. Images are an incredibly powerful medium in conveying information – both positive and negative, and in capturing our imagination. The visual assessment of windfarms, however, involves much, much more than just looking at pictures. It requires detailed site assessment of a visual resource while also considering data on the potential effects of a development.

2 While images are very powerful and useful in communicating information, they can never tell the whole story. They can never replicate the experience of seeing a windfarm in the landscape, whether they are photographs, maps, sketches or computer generated visualisations, and prepared to the highest specification and skill possible. Similarly, however, assessment in the field will be considerably limited without the benefits of technical data such as visibility maps and visualisations that demonstrate the technical aspects of a proposed development.

3 Visual analysis forms just one part of a Visual Impact Assessment (VIA), the process by which the potential significant effects of a proposed development on the visual resource are methodically assessed. In turn, VIA forms just one part of a Landscape and Visual Impact Assessment (LVIA) and the wider process of Environmental Impact Assessment (EIA). All of these processes are directed by specific guidelines and/or legislation, some of which are listed in figure 3 and Appendix i.

4 Detailed information on the process of LVIA, together with a recommended methodology, are provided within the 'Guidelines for Landscape and Visual Impact Assessment' (GLVIA), produced by The Landscape Institute and Institute of Environmental Management and Assessment (2002).

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5 The purpose of an EIA is to identify and assess the potential significant effects of a proposed development. Its findings are presented within an Environmental Statement (ES). An applicant will usually appoint specialists to conduct the different studies that make up this report; for VIA, it is usual to appoint landscape architects.

6 A combination of illustrative techniques are used during the VIA process. The most commonly used include computer generated visibility mapping, wirelines and photomontages, together with hand drawn diagrams and sketches. These can show where a proposed development may be seen from and how it may appear in terms of its basic characteristics such as size, pattern and shape.

7 It is important to stress that visualisations, whether they are hand drawn sketches, photographs or photomontages, will never appear ‘true to life’. Rather, they are merely tools to inform an assessment of impacts; and, like any tool, their application requires careful use. Interpretation of visualisations always needs to take account of information specific to the proposal and site, such as variable lighting, movement of components, seasonal differences and movement of the viewer through the landscape. Thus visualisations in themselves can never provide the answers – they can only inform the assessment process by which judgements will be made.

How this Good Practice Guidance has been developed

8 This guidance has been prepared by independent consultants acting on the behalf of Scottish Natural Heritage (SNH), the Scottish Society of Directors of Planning (SSDP) and the Scottish Renewables Forum (SRF). It is derived mainly from research reported within the publication 'Visual Assessment of Windfarms: Best Practice’ by the University of

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Newcastle (2002). This original work has been updated and refined through reference to a range of material and sources, including:

• a review of current VIA practice represented by a range of windfarm ESs; • a review of current illustrative methods representing a range of interests, experience and expertise; • advice from participants at three workshops involving the key stakeholders of windfarm developers, consultants and planning officers (the latter also describing key concerns raised by the public); and • existing guidance (see ‘Other sources of information’ section).

9 This work was begun by the University of Newcastle in 2003, led by John Benson, and later completed by horner + maclennan and Envision.

Aims and Objectives of the Good Practice Guidance

10 This Good Practice Guidance focuses upon only the Visual Impact Assessment (VIA) element of Landscape and Visual Impact Assessment (LVIA). This process usually requires visibility maps and visualisations that are then used differently by different people for different purposes. Some visualisations will directly inform judgements made within the VIA (and thus guide the scale, location and design of the windfarm), while others will be used for general illustrative purposes. Their common aim, however, is to help inform judgements on the potentially significant effects of a proposed windfarm on the landscape and visual resource.

11 The accuracy of these illustrations is often questioned. Sometimes this is due to unfamiliarity and thus a misunderstanding regarding their specific purpose, and the limitations of visibility maps and visualisations to depict what can actually be seen by the naked eye.

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The University of Newcastle (2002) highlighted that photomontages “..can imply a degree of realism that may not be robust, and can seduce even a critical viewer into investing more faith in that realism that may be warranted”. Sometimes, their accuracy is questioned simply because there remains considerable variation between how illustrations are presented within ESs, and these different methods have various strengths and weaknesses.

12 The methods used to produce visibility maps and visualisations have developed significantly since the first windfarms were planned in the UK at the beginning of the 1990s. This has been aided by continued effort on the behalf of many consultants, developers, researchers and consultees to try to find more effective ways of representing the effects of windfarms in the landscape. There has also been a progressive change in the availability, cost and capability of computers, software and digital data used to produce computer-generated images. This situation continues to change as new techniques develop.

13 For these reasons, Scottish Natural Heritage in conjunction with Planning Authorities (represented by the Scottish Society of Directors of Planning) and the Scottish Renewables Forum has produced this Good Practice Guidance.

Figure 1: The aims of the Good Practice Guidance

• To advise on the purposes and uses of different visibility maps and visualisations of windfarms, ensuring that their relevant strengths and limitations are better recognised and understood; • To advise on the various methods of producing visibility maps and visualisations; • To promote and encourage good practice in the production of computer generated visibility maps and visualisations; • To ensure that the approaches, methods and techniques used in the production of visualisation tools and illustrations are technically sound and robust and hence carry credibility; and • To enable the Good Practice Guidance to be easily updated as new methods and techniques become established.

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What the Good Practice Guidance is not

14 The Good Practice Guidance is designed to summarise and explain what is feasible, available and reasonable in terms of current good practice in the production of illustrations. However:

• It is not an exhaustive guide to all possible techniques, nor does it prescribe a single method or brand of software; • It is not intended to be highly prescriptive, nor suggest that there is a 'one size fits all' solution; • It does not remove the need for consultation, good judgement and the adaptation of tools and techniques for different developments and different locations; and, most importantly, • It is not intended to inhibit or stifle innovation in the development and use of new approaches, tools and techniques. 15 This guidance specifically applies to onshore windfarms within Scotland; however some of the principles established through this guidance may be relevant to other development types or within other locations. Additional guidance may be developed in the future that builds upon this work, exploring and/or incorporating additional aspects of windfarms, such as cumulative assessment or offshore developments.

16 The production and use of visibility maps and visualisations are but one aspect of a complex interplay of factors considered within the VIA process (and thereby also the EIA process). Hence, it is neither feasible nor appropriate to define a single approach, as agreement requires consultation and site-specific judgements. Rather, this guidance seeks to identify the key factors that need to be considered when making decisions about what is the most appropriate approach for a particular project (as later summarised within figure 35).

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17 In addition to computer generated (or computer assisted) visualisations, landscape and architectural design has for centuries been aided by the illustration of proposed change by hand drawn sketches and diagrams. Given that the creation and use of these images is long established, this Good Practice Guidance will not consider these methods in any detail, although they are mentioned in paragraphs 223-228.

18 Methods of visualisation using computer animation and video montage were not included within the scope of this study. This was because:

• These were not assessed within the original study by the University of Newcastle (2002); • They rarely form an essential part of the ES, but tend to be a supplementary tool; and • There has so far been insufficient methodical assessment of how these compare against individual built schemes within Scotland.

19 Finally, it should be stressed that the quality of a LVIA depends on much more than just good practice visibility maps and visualisations. These are just tools to inform the assessment process and, even if of a high quality, will not diminish the requirement for a thorough and professional LVIA. Equally, however, it is important to stress that it is extremely difficult to carry out a high quality LVIA without visibility maps and visualisations that meet good practice standards.

Who should use the Good Practice Guidance?

20 This Good Practice Guidance is intended for all those with an interest in the VIA of windfarms. • For developers, the guidance offers an overview of what is technically available, feasible and reasonable in terms of producing visibility maps and visualisations so that they can be better informed when instructing their consultants and

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commissioning ESs, as well as discussing proposals with determining authorities and consultees. • For landscape architects and other specialist consultants, the guidance advises on the technical specifications for a range of visibility maps and visualisations commonly used in VIA practice and advises on their strengths and weaknesses. • For consultees, the guidance presents recommended standards in terms of the quality and type of visibility maps and visualisations that can be used to inform EIA, and advises on how these should be interpreted and used. • For officers from planning authorities/ determining authorities, the guidance also presents recommended standards as described above for consultees. It will also inform scoping opinions and assist planning officers and decision-makers in their interpretation and use of visibility maps and visualisations as presented within Environmental Statements. • This document is not targeted at the general public, given its specialist nature and technical content. However, for those members of the public particularly interested in this subject, the guidance should aid their understanding of what visibility maps and visualisations can and cannot do, and how this information should be interpreted when included within a VIA or ES.

How to use the Good Practice Guidance

21 The guidance is presented in different sections so that it can be used as a reference tool. Not all of the information contained within the guidelines will be relevant in all circumstances.

22 The main body of this guidance is divided into a series of sections which broadly relate to the stages of a VIA process as shown in the diagram below. It is intended that the loose-leaf format will allow flexibility of use

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and future updating of the guidance as new techniques are developed and experience grows.

23 The core of the Good Practice Guidance lies in chapters 2, 3 and 4 where the technical recommendations for different tools and techniques are explained as well as their uses and limitations. Where recommendations are based on complex and/ or detailed technical factors, these are further explained in the technical appendices.

Figure 2: Structure of the report Windfarm proposal

C CHAPTER 2 Identify from where the proposal may be seen O Zone of Theoretical Visibility using visibility mapping resulting in the production of a R Zone of Theoretical Visibility (ZTV) E

G CHAPTER 3 Select key places from which the Viewpoints proposal may be seen - the viewpoints U I D A CHAPTER 4 Develop visualisations N Visualisations fit for purpose - photographs, wirelines, photomontages, video montage and virtual reality C E

Application of tools using the tools to assess the magnitude and significance of visual impacts

Glossary of key terms

24 A glossary is included within Appendix ii. However there are a number of key terms used throughout this document that need to be explained at an early stage as follows:

Digital Terrain Model (DTM). This term refers to the way in which a computer represents a piece of topography in 3-dimensions as a digital model. The

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terms Digital Elevation Model, Digital Ground Model and Digital Height Model are also used and are synonymous.

Landscape and Visual Impact Assessment (LVIA). This is the professional and methodical process by which assessment of the impacts of a proposed development on the landscape and visual resource is undertaken. It comprises two separate and distinct parts - Landscape Impact Assessment and Visual Impact Assessment.

Landscape Impact Assessment. This is the process by which assessment is undertaken of the impacts of a proposed development on the landscape, its character and quality. GLVIA (2002) states that "Landscape effects derive from changes in the physical landscape, which may give rise to changes in its character and how it is experienced".

Panorama. An image covering a horizontal field of view wider than a single frame. Panoramic photographs may be produced using a special panoramic camera or put together from several photographic frames. Wirelines and photomontages may also be produced as panoramas. See Appendix B.

Photomontage. A visualisation which superimposes an image of a proposed development upon a photograph or series of photographs. For windfarms, photomontages are conventionally used to illustrate proposed wind turbines within their setting. However tracks and other ancillary structures may also be shown. Photomontages are now mainly generated using computer software.

Significant. This term is used to describe the nature of a change. VIA, LVIA and EIA aim to identify and assess significant effects. For each project, levels of significance will be categorised and defined in relation to the particular nature of the resource and the proposed development.

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‘Telephoto Photomontage’. A type of photomontage (see above) based on a photograph taken using a telephoto lens (over 50mm when using a 35mm camera).

Visual Impact Assessment. This is the professional and methodical process which is used to assess the impacts of a proposed development on the visual appearance of a landscape and its visual amenity. GLVIA (2002) states that "visual effects relate to the changes that arise in the composition of available views as a result of changes to the landscape, to people's responses to the changes, and to the overall effects with respect to visual amenity".

Visualisation. Computer simulation, photomontage or other technique to illustrate the appearance of a development. This term is used within this Good Practice Guidance to include photographs, but not Zone of Theoretical Visibility (ZTV) maps.

Wirelines. These are also known as wireframes and computer generated line drawings. These are line diagrams that are based on DTM data and illustrate the three-dimensional shape of the landscape in combination with additional elements. For windfarm projects, wirelines usually show just wind turbines. However, some software also allows the representation of additional elements such as access tracks and masts.

Zone of Theoretical Visibility (ZTV). Also known as a Zone of Visual Influence (ZVI), Visual Envelope Map (VEM) and Viewshed. This represents the area over which a development can theoretically be seen, based on a DTM. The ZTV usually presents a ‘bare ground’ scenario - that is, a landscape without screening structures or vegetation. This information is usually presented upon a map base.

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Visual Impact Assessment (VIA)

25 Visibility maps and visualisations are only tools. Within VIA, they are produced to aid the identification and assessment of significant visual effects.

26 General guidance on assessing significance of effects is contained within the Guidelines for Landscape and Visual Impact Assessment (Landscape Institute & Institute of Environmental Management & Assessment, 2002). Consequently, this document does not include guidance on this topic. Rather, this report focuses on the choice, production and use of visibility maps and visualisations.

Cumulative Landscape and Visual Impact Assessment (CLVIA)

27 As the number of proposed windfarms increases in Scotland, the issue of potential cumulative impacts becomes ever more important. This Good Practice Guidance will not, however, provide specific guidance on cumulative visibility maps and visualisations. This is for two main reasons:

• It is believed that Good Practice Guidance on the visual representation of individual windfarms should be established and adopted before venturing into the more complex arena of cumulative issues; and • when this study was first commissioned, there was little existing research on the effectiveness of CLVIAs and the respective cumulative impacts of windfarms.

It is hoped, however, that guidance on the cumulative visual representation of windfarms will be produced in the near future. In the meantime, it is recommended that reference be made to the relevant documents listed within the following section and Appendix i.

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Other sources of information

28 This Good Practice Guidance should be read in combination with existing guidance for LVIA, VIA, EIA and CLVIA. Existing guidance particularly relevant to the LVIA of windfarms in Scotland is included within the following figure 3:

Figure 3: Existing guidance relevant to the LVIA of windfarms

• Landscape Institute & Institute of Environmental Management & Assessment (LI-IEMA). 2002. Guidelines for Landscape and Visual Impact Assessment. 2nd Edition. Spon Press, London. • Scottish Executive. 1999. Planning Advice Note 58. Environmental Impact Assessment. • Scottish Executive. 2002. Planning Advice Note 45. Renewable Energy Technologies. • Scottish Executive. 2000. National Planning Policy Guidance 6. Renewable Energy Technologies. • Scottish Natural Heritage. 2001. Guidelines on the Environmental Impacts of Windfarms and Small Scale Hydroelectric schemes. SNH:Redgorton, Perth. • Scottish Natural Heritage. 2003. Policy on Wildness in Scotland’s Countryside (Policy Statement No 02/03). Available at www.snh.gov.uk. • Scottish Natural Heritage. 2005. Cumulative Effect of Windfarms. Version 2 revised 13.04.05. Guidance. Available at www.snh.gov.uk. • Scottish Natural Heritage. 2005. Environmental Assessment Handbook, 4th edition. Available at www.snh.gov.uk. • University of Newcastle. 2002. Visual Assessment of Windfarms: Best Practice. SNH: Redgorton, Perth.

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29 In addition, a number of landscape capacity studies for windfarms have been produced covering different parts of Scotland. For details, refer to www.snh.gov.uk.

30 The Landscape Institute produced Advice Note 01/04 in June 2004 on the ‘Use of Photography and Photomontage in Landscape and Visual Assessment’. Further details on the issues raised by this note are included in the Technical Appendices A-E.

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2 Zone of Theoretical Visibility

31 The term ‘Zone of Theoretical Visibility’ (ZTV) is used to describe the area over which a development can theoretically be seen, and is based on a Digital Terrain Model (DTM) and overlaid on a map base. This is also known as a Zone of Visual Influence (ZVI), Visual Envelope Map (VEM) and Viewshed. However the term ZTV is preferred for its emphasis of two key factors that are often misunderstood:

• visibility maps represent where a development may be seen theoretically – that is, it may not actually be visible in reality, for example due to localised screening which is not represented by the DTM; and • the maps indicate potential visibility only - that is, the areas within which there may be a line of sight. They do not convey the nature or magnitude of visual impacts, for example whether visibility will result in positive or negative effects and whether these will be significant or not.

32 This section of the report highlights the following key issues with regard to ZTVs:

• ZTV data ZTV • ZTV calculation preparation • Viewer height • Extent of ZTV

• Base map • Colour overlays Presentation of • Visibility bands ZTV • Recording ZTV information information • ZTV development for a project • ZTV production

Good Practice Guidance Summary

23 33 ZTVs are calculated by computer, using any one of a number of available software packages and based upon a DTM that represents topography. The resulting ZTV is usually produced as an overlay upon a base map, representing theoretical visibility within a defined study area.

34 Production of ZTVs is usually one of the first steps of VIA, helping to inform the selection of the study area in which impacts will be considered in more detail. ZTVs provide the following information:

• where visibility of a windfarm is most likely to occur; • how much of the windfarm is likely to be visible (within bands of various numbers of turbines); • how much of the wind turbines is likely to be visible if separate ZTVs are produced showing visibility up to blade tip height, and visibility up to the hub or nacelle; and • the extent and pattern of visibility.

In combination with a site visit, possibly with initial wireline diagrams, this information enables the landscape architect or experienced specialist assessor to identify a provisional list of viewpoints, and allows the determining authority and consultees to judge how representative these are and whether they include particularly sensitive vantage points.

24 35 Importantly, ZTVs indicate areas from where a windfarm may be seen within the study area, but they cannot show how it will look, nor indicate the nature or magnitude of visual impacts.

Table 1: Uses and limitations of ZTVs (numbers in brackets refer to paragraph numbers in text)

USES OF ZTVs LIMITATIONS

• A ZTV gives a good indication of the broad y A ZTV is only as accurate as the data on which it areas from where a windfarm might be seen is based (49-51). (31, 34). y A ZTV cannot indicate the potential visual • A ZTV predicts theoretical visibility (31). impacts of a development, nor show the likely significance of impacts. It shows potential • A ZTV is a useful tool as long as its theoretical visibility only (31, 33). limitations are acknowledged. y It is not easy to test the accuracy of a ZTV in the field, although some verification will occur • The ZTV can be used to identify viewpoints during the assessment of viewpoints. from where there may be significant visual

impacts, enabling an assessment to consider y A ZTV, if prepared to good practice guidelines, these with the aid of visualisations (34). will be adequate as a tool for VIA; however is

will never be entirely ‘perfect’ for a number of • A ZTV is a useful tool for comparing the technical reasons. Most importantly, in order to relative visibility patterns of different handle large areas of terrain the DTM data is windfarms or different wind turbine layouts based on information which does not allow (84-85). detail to be distinguished below a certain level.

There are also differences in the way that the

software package ‘interpolates’ between heights in the calculations made (44-45).

25 ZTV preparation

ZTV data

36 A ZTV is produced using a computer-based software package. Several of these are commercially available, for example, most windfarm design packages and many Geographical Information System (GIS) packages have this facility. However, operation of even the most user-friendly package requires a high level of expertise and understanding of all the specific features and assumptions applied by the software.

37 ZTV production begins with a Digital Terrain Model (DTM) that represents the ground surface as a mesh of points. This may form a regular grid of squares when seen on plan, known as a Square Grid DTM, or an irregular network of triangles, known as a TIN (Triangulated Irregular Network).

38 A Square Grid DTM is fundamentally incapable of Square grid DTM representing terrain features smaller than the cell size, such as a small knoll or outcrop. Such features are either lost between grid points or represented by one point only. A TIN can, in principle, represent finer detail than a Square Grid DTM as it can represent all the detail shown by contours. However, in practice, a Square Grid DTM with a suitably chosen cell size will represent almost as much detail and may interpolate TIN better between contours on less steeply sloped land.

39 Both formats are acceptable. The choice between them is most likely to depend on the software being used and from where the data is sourced. It is common practice for a Square Grid DTM to be chosen if OS data is to be used, while a TIN is used when based on independent and/or detailed survey data, enabling high and low points to be better represented.

40 The Ordnance Survey (OS) supply data in two formats - gridded, which has already been interpolated into a

26 Figure 4: Comparison digital terrain models

Wireline drawing of OS Panorama DTM at the supplied 50m grid size

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Wireline drawing of OS Profile DTM of the same area at the supplied 10m grid size. As would be expected, far more terrain detail is apparent in this DTM. Also, because the source is 1:10,000 contours rather than 1:50,000, the shapes of quite large landscape features are better represented. Square Grid DTM, and as contours, which is the usual starting point for constructing a TIN.

41 The OS Square Grid DTM product, ‘Landform Profile’, uses a 10m cell size and is interpolated from the contours shown on OS 1:10,000 and 1:25,000 scale mapping. An earlier product, ‘Landform Panorama’, once temporarily withdrawn, but now re-launched, uses a 50m cell size and is derived from 1:50,000 scale mapping.

42 The 10m Landform Profile DTM provides a more precise representation of topography than the 50m Landform Panorama DTM, as illustrated within figure 4, although, not surprisingly, it is more expensive. Landform Panorama DTM is less precise not only because of the larger cell size, but also because the shape and detail of the 1:50,000 scale contours used as the source data are themselves more simplified than the 1:10,000 scale contours. If Landform Panorama DTM is used, it is important that the resolution at which it is provided is used and the grid is not down-sampled, as shown in figure 5.

43 OS Landform Panorama DTM is considered an acceptable product, especially if the landform is simple. However the recommended preference is for OS Landform Profile, especially if the terrain is very rugged.

44 Although considered adequate for the purposes of VIA (given that ZTVs are just a tool for assessment), the accuracy of most DTMs is limited and they do not include accurate representation of minor topographic features or areas of recent topography change, such as open cast coalfields, spoil heaps and mineral workings. Known significant discrepancies between the DTM and the actual landform should be noted in the ES text. If survey information on recent topographic change is available, together with the necessary software to amend the DTM, it may be

28 Figure 5: Comparison of ZTV grid size

ZTV of windfarm based on OS Landform Panorama data at the supplied 50m grid size

ZTV of windfarm based on OS Landform Panorama data with the grid size downsampled to 250m. Some small areas of theoretical visibility are not shown at all, while others are over-represented. (Scale 1:250,000) useful to include it. However, any changes to the DTM should also be noted in the text.

45 The OS provides accuracy figures for each of its data products (expressed statistically as root-mean-square error in metres). Where the DTM is obtained from another source, the expected accuracy can also usually be obtained from the data supplier. These accuracy figures should be stated within the ES. However, non- experts may find it difficult to extrapolate from this a judgement of precision. Therefore it is preferable if these figures are accompanied within the ES by a general statement from the landscape architect or experienced specialist assessor that confirms that the levels of accuracy fall within acceptable limits.

46 An alternative to the OS DTM products is NextMap which offers a grid with a cell size of 5m. This is a Digital Surface Model (DSM) derived from airborne radar data. As its name implies, the grid is a model of the upper surface of the land, including vegetation, buildings and other ground cover. As such, it can provide a good basis for calculating visibility including the effects of such features. A parallel product is also available from the same source which is a DTM with a cell size of 5m or 10m. However, as this is derived from the DSM with ground heights estimated from the height to the top of ground cover, its accuracy is not entirely reliable, except in very open areas.

47 ZTV production also requires data on the locations and heights of the proposed wind turbines. For the purposes of ZTV calculation, it is sufficient to represent each proposed turbine as a single point in space, located directly above the centre of the proposed base of the turbine. The height specified is usually that at either hub/nacelle height or at a blade tip pointing straight up, but can be at any other point on the turbine depending on the ZTV analysis required.

48 It is recommended that separate ZTV calculations are run for the overall height (to blade tip) and for the

30 height of the turbine to its hub (representing the nacelle that houses the generator on top of the tower). This is a useful comparison that helps to identify areas where turbine blades may be visible, but not the tower or nacelle. For a single proposed turbine, it can also be useful to run ZTVs with other targets, such as 1m above the ground and at the base of the rotor sweep which, in combination, provide an indication of where almost all the turbine or just the rotor sweep may be visible.

ZTV calculation

49 In principle, all ZTV software packages are similar, but variations in the detailed routines (algorithms) used for each mean that slight variation in results may be produced by different packages using the same data. Most differences stem from different choices in the shape of the ground surface that the software assumes to exist between the grid points in the DTM and tend to result in insignificant discrepancies. Some software packages offer both a standard and 'fast' option for ZTV calculation. 'Fast' implies the use of mathematically approximate methods in order to speed up the computation, which tends to result in greater errors. It is recommended that this is only used to obtain a quick, provisional result which will be later superseded by a more comprehensive calculation. It is also important, that users of ZTV software ensure that they are clear about the technical limitations inherent in their chosen package.

50 Visibility is affected by earth curvature and the refraction (bending) of light through the atmosphere, particularly at greater distances, as shown on figure 6. Therefore this effect should be included in the ZTV calculation as its absence will tend to overestimate visibility. Appendix F treats this issue in more detail and includes a table of the vertical difference introduced by earth curvature and refraction with distance. At 10km, the vertical difference is enough to

31 Figure 6: The effects of earth curvature upon a ZTV

a: ZTV of windfarm including effects of earth curvature and atmospheric refraction

b: ZTV of windfarm without earth curvature or refraction

c: Above images superimposed. The yellow areas 32indicate areas from which the windfarm would not be theoretically visible but which are shown as visible on the ZTV map without earth curvature or refraction. The areas principally affected are naturally those with more distant views. Depending on the shape of intervening topography, these areas can be quite large. (Scale 1:250,000) hide a single storey house and it increases more rapidly thereafter.

51 These limitations, inherent in the data and in the method of calculation should always be acknowledged and, if possible, quantified. Note that these limitations may either over or under-represent visibility. As a general rule, ZTVs should be generated to err on the side of caution, over-representing visibility. There are no defined thresholds for this allowance; rather, judgements will need to be made based on professional expertise in this field.

52 A ZTV usually represents visibility as if the ground surface was bare; that is, it takes no account of the screening effects of intervening elements such as trees, hedgerows or buildings, or small scale landform or ground surface features. The ZTV also does not take into account the effects of weather and atmospheric conditions in reducing visual range. In this way, the ZTV can be said to represent a ‘worst case scenario’; that is, where the windfarm could potentially be seen given no intervening obstructions and favourable weather conditions (while accepting that the DTM data can sometimes understate visibility at the very local level). To understand how this might be affected by typical visibility conditions within a particular area, Met Office data on visibility conditions can be obtained.

53 Some software does allow the use of more sophisticated datasets, enabling some screening effects to be taken into account. Examples are the application of data which applies different ‘thickness’ to various land uses such as forestry and urban areas, and the use of digital surface data obtained from laser-based aerial surveys which represent the tops of vegetation and buildings. At present, for most projects, this data does not make a considerable difference to the pattern of visibility, while tending to be very expensive; therefore, its use should be limited to specific projects where the benefits will be notable.

33 Care needs to be taken when assessing this kind of information, as its accuracy is limited by data availability and the constant change in landscape conditions. The results will also be closely tied to the specifications used, for example the height of trees; as a consequence, these should be noted within the ES.

54 In some situations, it might be useful to map other characteristics such as the number of wind turbines seen against the skyline or what proportion of the horizontal field of view is likely to be occupied by the visible part of a windfarm, known as the ‘horizontal array angle’. This information is particularly useful for considering the impact of a very large windfarm or several windfarms where they would be seen together within panoramic views. However, for most windfarms, the width of view can usually be more simply judged by considering the distance to the development in combination with wireline diagrams from specific viewpoints.

55 Any analyses that calculate characteristics other than simple visibility over base ground should be produced in addition to bare ground visibility, not as an alternative to it. Although these currently have various limitations as described above, improvement and development of this kind of data is likely to occur in the future.

Viewer height

56 As the ZTV calculates the number of wind turbines visible at each of a number of points just above the ground, a measure of viewing height is required. Often this is set at 1.5–2 metres. The rationale for this height is usually given as relating to viewer height and/or camera height to maximise correlation between the ZTV and visualisations. However, although viewer height is an important element of the ZTV calculation, the error inherent in the DTM is of about the same magnitude (1.5 metre RMS error for Landform Profile, 2.5 metre RMS error for Landform

34 Panorama). Consequently, it is recommended that the viewer height adopted should try to both avoid errors arising from DTM and inaccuracy close to a viewpoint, for example due to local undulations, as well as taking into account the typical height of a viewer. To satisfy these criteria, it is recommended that a standard viewing height of 2 metres is used.

Extent of ZTV

57 As previously discussed, a ZTV map illustrates locations within a study area from where a development is potentially visible. However, just because a development can be seen, it does not automatically follow that this will result in significant visual impacts. This creates a circular process of decision-making. That is: the distance of a ZTV should extend far enough to include all those areas within which significant visual impacts of a windfarm are likely to occur; yet the significance of these visual impacts will not actually be established until the VIA has been completed; and the VIA process needs to be informed by the ZTV. As part of this cycle of assessment, the recommendations given within Table 2 below act as a starting point. However, the actual extent required may need to be adjusted inwards or outwards according to the specific characteristics of a landscape and/or proposed development. It is advised that determination of the extent of the ZTV should be discussed and agreed with the determining authority and consultees.

35 Figure 7: Process of determining ZTV extent

ZTV Should extend far enough to include all areas within which there is potential for significant visual impacts to occur

LVIA informed by Significance of ZTV visual impacts judged through LVIA

Table 2: recommended distance of ZTV Height of turbines including Recommended ZTV distance from rotors (m) nearest turbine or outer circle of windfarm (km)

up to 50 15 51-70 20 71-85 25 86-100 30 101-130* 35*

These figures are based on recommendations within ‘Visual Assessment of Windfarms: Best Practice’ (University of Newcastle, 2002). * This category was recommended by the late John Benson, based on experience and extrapolation of evidence presented within the publication cited above.

36 58 The extent of a ZTV is typically defined as a distance from the outer turbines of a windfarm. This can be to the nearest turbine or as incorporated within a specific shape, as shown below. The most suitable option will usually depend on the layout of the windfarm.

Figure 8a and 8b Measuring the extent of a ZTV

Outer limit of map base Minimum radius of ZTV Turbine

Page edge

Outer radius of windfarm, formed by smallest circle including all turbines

Outer limit of map base Minimum limit of ZTV

Turbine

Page edge

Outer limit of windfarm, formed by smallest shape including all turbines

59 If a windfarm is very small and concentrated in layout, typically 5 wind turbines or less, it may be reasonable to measure the extent of the ZTV from the centre of the site. However this should always be agreed with the determining authority and consultees.

37 60 ZTV information is often shown as stopping at the outer radius of the ZTV and not the edge of the map base, unlike other information usually presented within a LVIA such as landscape character and landscape designations. This cut-off can appear slightly irrational upon a rectangular base map, seeming to imply that visibility ceases at a defined distance (although it is acknowledged that, when considering cumulative visibility from multiple developments, limiting data to this boundary may improve clarity of the separate ZTVs). Consequently, it is recommended that a ZTV overlay for an individual windfarm should extend to the border of the map that includes the recommended ZTV distance.

Figure 9a and 9b Presentation of ZTV information

Current convention

Radius of ZTV and limit of data

Base map extent

Recommendation

Extent of data

Radius of ZTV

38 61 Table 2 provides recommended distances for ZTV data. These are based on turbine height. However this is just one factor which affects potential visibility and, as discussed previously, the ZTV distance may need to be adjusted up or down depending on the specific environmental conditions and landscape context in addition to the nature and scale of the proposed development.

62 The recommendations within Table 2 are based upon the total height of a turbine to blade tip. However it is important to understand that visibility of turbine blades and turbine towers differs. At close distances, turbine blades often seem more noticeable than the towers due to their movement; while at far distances, the turbine towers are usually more prominent because of their greater mass, and may actually be the only element visible at very great distances. This creates a slightly odd situation; that is, the categorisation of visibility to blade tip at far distances, while turbine blades might not actually be visible at these distances. However, the reality is that the categories of turbine height used in Table 2 act only as a ‘yard stick’, and similarly defined categories based on tower or hub height would likely provide the same recommendations. The only notable discrepancy might be if a wind turbine was unusual in its proportions, for example having a high hub with a smaller than usual rotor diameter. However the difference of visibility that would occur in these circumstances at far distances is unlikely to be significant; and, even if it were predicted as being significant, the difference could be accommodated by adjusting the ZTV as discussed in paragraph 61above, as part of the usual process of confirming ZTV extent for a specific scheme.

63 For turbines between 53 and 85 metres total height, the University of Newcastle (2002) reported that it was not possible to identify the taper of a turbine tower or identify nacelle detail at distances over 10km. They

39 also reported that blade movement could be detected up to15km in clear conditions, or where there was a strong contrast between the rotors and the sky, but that a casual observer may find blade movement unnoticeable beyond 10km. These observations highlight that visibility of the different aspects of wind turbines will vary. However most new wind turbines are of heights much greater than those on which these observations are based and, unfortunately, it was not within the scope of this study to carry out site assessment of more recently built, taller wind turbines on which additional guidance could be based.

64 Some practitioners have suggested that, as it usually becomes difficult to see turbines clearly when over 30km away, extending a study area further than this is unlikely to ever be necessary. Although there is obviously some validity to this argument, it is nevertheless the case that some exceptional visibility conditions occur at times in Scotland. Combined with the fact that some key vantage points in Scotland, such as the tops of mountains or hills, are of very high sensitivity in terms of scenic value, some windfarms could clearly be seen at certain times from very sensitive locations at great distances away. This means it is feasible that, in exceptional circumstances, visibility of a windfarm or windfarms could result in significant effects beyond 30km. This highlights the importance of determining ZTV extent in agreement with the determining authority and consultees for a specific project.

65 It has been suggested that the ZTV radius should also depend on the number of wind turbines in a development. In purely technical terms, visibility extent is not actually dependent on the number of turbines, as a single 100m turbine would technically be as visible as 100 x 100m turbines from a set distance. However a larger windfarm would obviously be more noticeable, particularly as the eye tends to be attracted to groups or patterns when it might otherwise miss a

40 single element. So although the guidance included in Table 2 above would be applicable for most windfarms and should be used as the ‘starting point’ for ZTV production, it may be acceptable to adopt a reduced study area for a smaller development and it may be advisable to explore a wider area for a larger windfarm. This should be agreed in consultation with the determining authority and consultees.

Presentation of ZTV information

Base map

66 A ZTV should be superimposed on a clearly legible base map at a recognised standard scale, such as the Ordnance Survey (OS) 1:50,000. For an ES in A3 format (420 x 297mm), showing a ZTV extending from a site up to a 30km radius, a scale of 1:250,000 will be required to fit a single page. At this scale, the ZTV can only provide an overview and thus another more detailed ZTV is required for use as a working tool for VIA, consultation and design. This should be provided on a 1:50,000 OS base (copied at either 1:50,000 or 1:100,000) to be able to illustrate sufficient detail, as shown in figure 10a and b. However a ZTV at this scale obviously results in a much larger map as detailed within Table 3. Conventionally, this is presented as either a single fold-out plan or as separate A3 sections (with minimum 1km overlaps).

67 Single maps are usually clearer as they show the whole study area on one sheet, but they may be more difficult to handle and require folding and insertion within a wallet in the ES. Separate A3 maps will divide the study area, and possibly the site, into sections, so a supplementary and overlapping site-centred map may also be required. Although, a high number of sheets may be required to cover an entire study area in this way, as shown in figure 11, not all of the study area may require detailed coverage if the ZTV overview identifies that large areas within the study area would

41 Figure 11: Overlap of A3 sheets to illustrate ZTV coverage

Key

study area A3 page

1: 100 000

15 km radius 20 km radius25 km radius 30 km radius 35 km radius

1: 50 000

15 km radius 20 km radius 25 km radius

30 km radius 35 km radius

minimum 1km overlap

42 have no visibility of the proposed development at all. Conversely, for particularly sensitive areas, it may be useful to produce large-scale enlargements (representing the information used by the assessor when zooming in on the ZTV on a computer screen) in order to examine small areas of theoretical visibility.

Table 3: Size of ZTV at various scales and to fit standard paper sizes

ZTV extent Size of single map Number of A3 separate (from single sheets* point) 1:100,000 1:50,000 1:100,000 1:50,000

Image size Paper size Image Paper size size 15km 300x300 A2 600x600 A0 2 6

20km 400x400 A2 800x800 A0 2 6

25km 500x500 A2 1000x1000 - 4 12

30km 600x600 A0 1200x1200 - 6 15

35km 700x700 A0 1400x1400 - 6 24

68 For a ZTV to be clear and legible when overlain with colour shading, the base map needs to be in greyscale. This is to prevent confusion of overlays, for example a yellow overlay upon blue coloured lochs will appear as green, and this could be confused with woodland (figure 12). To maximise legibility, it is also important that the base map is of a high quality resolution and not too light or dark.

69 Each individual wind turbine should be clearly marked upon the ZTV, usually shown as a small circle or ‘dot’, depending on the base map against which it has to be distinguished. Although it is recommended that the ES includes a map that shows individual turbine numbers and their grid coordinates, and that the ZTV should include reference to this map, it is best not to include this information on the ZTV itself in order to keep this map as clear as possible.

70 It is recommended that viewpoint locations (numbered) also be shown on the ZTV, although it is important to

43 label these carefully to avoid obscuring vital ZTV information. This requirement is discussed further in paragraph 114.

71 For ease of legibility it is recommended that the ZTV show concentric rings to indicate different distances from the proposed development, for example 10, 20 and 30 km. However, the areas encircled by these rings should not be shaded or coloured as this may imply a direct relationship between distance and relative visibility or visual impact that would be misleading. To maintain legibility, the number of rings should also be limited.

72 Where ZTVs need to show potential visibility of different components of the wind turbines, this should be clearly explained as follows:

• a ZTV ‘to blade tip’ shows potential visibility of any part of a wind turbine up to its highest point (but not all of the wind turbine would necessarily be seen); • a ZTV ‘to hub’ or ‘to nacelle’ shows potential visibility of any part of a wind turbine up to the height of its hub or nacelle (but not all of the wind turbine tower would necessarily be seen); and • Comparison between ZTVs to blade tip and nacelle/hub allows identification of those areas from which the turbine towers might not be visible, but the blades (or part of these) would.

Colour Overlays.

73 Areas of potential visibility should be illustrated by a colour overlay. This should be slightly transparent so that the detail of the underlying map can be seen. Transparency within most software is expressed as a percentage – the amount of colour dots to clear space per unit area. The level of overlay transparency chosen should ensure that the detail upon the base map remains clearly discernible and no single colour appears more prominent than another.

44 74 If a range of colours is to be used, the shades and tones should be chosen carefully. Darker colours tend to read as portraying greater visibility than lighter colours whilst several colours of similar tone tend to convey information of equal importance. Using different shades of only one colour should generally be avoided as the distinctions between bandings usually appear merged and this can also imply a gradation of impacts represented by the decreasing shades that is misleading (figure 13a).

75 Legibility of a ZTV map tends to decrease with greater numbers of colours. For this reason, 7 colours should typically be the maximum used on any one map. It is recommended that these are bright and strongly contrasting as is illustrated within the scheme shown in figure 13b.

76 When selecting the colour palette to be used on a ZTV, it is important to consider how the colours would be seen by different viewers. One of the most important considerations is how the same colour will be represented differently according to the specification of

different computer screens and/or printers. It is Figure 14: Colour blindness recommended that practitioners always print out draft There are various web-based copies to check that any discrepancy between these tools which help map makers to still produces a clearly legible map, and then print out devise a palette of colours which are readable for the the final copies on the same printer. majority of the population and have colour charts which 77 When choosing a colour palette, it is also important to compare normal vision with various types of colour consider colour blindness. It is estimated that around blindness. 7-8% of males and 0.4-1% of females in Britain have ZTV maps should be checked some form of colour blindness. To them, legibility of for colour blindness legibility for maps depends on the type of colour blindness they instance by running them through a web based tool like have, the shade and brightness of the colour, and on Vischeck (www.vischeck.com) the contrast and combinations of colours used. This This allows any image to be shown as it would appear for requires careful consideration and is not just a simple people with the three main issue of avoiding the juxtaposition of red and green. types of colour blindness. It can be downloaded or used online. 78 While it would be useful to specify a standard range of colours consistently legible to colour blind people, it is impossible to develop this without also standardising

45 computer screens and colour printer reproduction. Thus, as an alternative, it is recommended that individual maps shown within each ES are checked for colour blind legibility using a quick clarification tool, for example as described within figure 14.

Figure 15: The effect of colour choice on ZTV clarity for colour blind people

The map on the left shows a possible colouring of a ZTV in five bands. The version on the right has been processed to simulate the effect of red/green colour blindness on these colours. (Carried out using the Photoshop filter distributed by Vischeck.com.) The blue and violet bands are difficult to distinguish, as are the orange and green bands. This map would not be easily readable by a person with red/green colour blindness.

Visibility bands

79 The theoretical visibility of different numbers of wind turbines (within a single development, or different windfarms within a cumulative ZTV) is usually distinguished upon a ZTV as different coloured bands. It is important to highlight that these bands differentiate between the visibility of different numbers of wind turbines as a tool for assessment. They are in no way intended to imply that greater numbers of turbines will necessarily result in higher levels of visual impact. These bands are particularly useful for

46 identifying potential viewpoints where the visibility of the windfarm varies considerably within an area.

80 The number of visibility bands should be high enough for each band to represent just a small range of turbine numbers, whilst low enough to avoid the need for too many colours which can appear confusing. For example, with 30 turbines, it is better to have 6 bands each covering 5 turbines (1-5, 6-10, etc) rather than 3 bands of 10 turbines which would provide limited resolution, or 10 bands of 3 turbines which would appear confusing. As mentioned in paragraph 75, it is recommended that no more than 7 colour bands should be used upon a ZTV.

81 Where equal banding is impossible (for example 11 turbines), then the widest band size chosen should apply to the lower end of the scale – for example 1-3, 4-5, 6-7, 8-9, 10-11, as greatest resolution is then retained where visibility is furthest.

82 For a small windfarm, an alternative to different coloured bands representing the visibility of turbine numbers, is to produce numerous ZTVs that each represent visibility of an individual turbine or individual group of wind turbines. This is a very useful tool for designing turbine position where a variable landform strongly affects visibility. The downside is the need to overlay or compare numerous ZTV maps. For anyone with access to a software package such as Photoshop, a high number of ZTVs can be better managed as transparent layers upon the same base. The various layers, representing visibility of different wind turbines or groups, can then be turned on and off to illustrate various visibility scenarios. However, production of maps in this format will inevitably need to occur only as a supplement to paper copies within an ES to ensure accessibility of this information for all.

47 Recording ZTV information

83 It is vital within an ES to include information on all the key assumptions made in ZTV production, and to summarise these within the VIA. This should include the following information:

Table 4: Information on ZTV production to be provided

1 The DTM data from which the ZTV has been calculated, including original cell size and whether this has been sampled down. 2 Confirmation that it is based on a bare ground survey, or provision of information on the specifications of additional land use data if this has been incorporated. 3 The viewer height used for the ZTV.

4 Confirmation that earth curvature and light refraction has been included. 5 The extent of the ZTV overlay as a minimum distance from the development, in addition to the frequency of any distance rings shown. 6 The numbers of wind turbines represented for each colour band. 7 The ‘target height’ used for the turbine and whether this is to hub or blade tip. 8 Confirmation that the ZTV software does not use mathematically approximate methods (see para 49).

ZTV development for a project

84 ZTV maps are very useful as a tool for comparing alternative turbine layouts, turbine numbers and turbine heights as a scheme develops. This also means that it is important to consider how they will be used throughout the entire VIA and EIA process, as well as how they are presented in the ES. This is because, as the design of a windfarm develops, the ZTV specification may need to change. For example, it may seem sensible to have 6 separate bands of 11 turbines for a 66 turbine windfarm and 6 separate bands of 9 turbines for a 54 turbine windfarm. But if a particular windfarm is reduced in size from 66 to 54 wind turbines it is important to keep the original bands

48 (that is 1-11, 12-22, 23-33, 34-44, 45-55, 56-66) even though there would not be any visibility shown for the highest band. Otherwise, it is impossible to directly compare the relative visibility of the original proposal and the revised windfarm. Sometimes there may be reasons why this practice is difficult, for example if amendment to a scheme would result in either too few or too many bands. In these situations, a judgement needs to be made regarding the most appropriate banding. If this involves amendment of the original range, it is useful to include an additional ZTV showing this range within the ES appendices.

85 Similarly, if an extension to an existing windfarm is proposed, it is recommended that the original range of bands is retained and supplemented by additional bands of the same interval to represent the additional turbines. For example, if the original ZTV bands were for 1-5, 6-10, 11-15 and 16-20 turbines, the proposed extension should have a ZTV that shows additional bands 21-25 and 26-30 turbines etc.

ZTV production

86 Where a ZTV map forms part of an ES, it should be accessible by all members of the public and thus should be produced on paper. However, as discussed in paragraph 82, in some cases it will be useful for the developer to provide the determining authority and consultees with a digital version in addition to the paper map. This also allows them to enlarge the ZTV on screen or focus in on particular areas of concern, making for a more flexible product. Production of this additional information will require agreement by the developer.

87 It has been suggested that ZTV information could also be made publicly accessible on developers' websites. However there are issues of map licensing and file sizes that are difficult to overcome, in addition to the difficulty in ensuring high quality resolution on a website, and the alternatives such as multiscale

49 mapping (for example streetmap.co.uk and getamap.co.uk) require very specialised (and expensive) hosting arrangements. A potential disadvantage of this to the developer is also that they have reduced control over the use and quality of any printed outputs.

50 Table 5: GOOD PRACTICE GUIDANCE SUMMARY

ZONE OF THEORETICAL VISIBILITY

Paragraphs Minimum requirements Preferred requirements in report ZTV data 41-45 OS 50m Panorama data if simple OS 10m Profile data. landform, OS 10m Profile data if rugged terrain. 44-45 Describe inherent limitations of data and methods of calculation.

52-53 Use bare ground data. In specific circumstances, datasets may be useful where there are likely to be significant screening effects, for example by vegetation or buildings, produced in addition to the bare ground ZTV;

Obtain data on visibility conditions in the area to help interpretation of visibility data. 48 ZTVs should be produced for both In specific sensitive situations, ZTV total height of turbines to blade tip should also show proportion of 54-55 and hub/nacelle height. turbines visible and/or numbers upon the skyline. 72 50 Earth curvature should be included in ZTV calculation.

50 The refraction of light should be included in ZTV calculation.

56 ZTV based on viewer height of 1.5 – Viewer height of 2.0m 2.0m.

57 ZTV extent to comply with Table 2 Aid legibility by showing concentric subject to consultation and circles upon ZTV map at defined 61-65 agreement with determining distances such as 10, 20 and 30km, authority and consultees. whilst avoiding confusion of lines. 71 58 Distances on which the ZTV is based should be measured from the nearest turbine or the smallest circle containing all the turbines of the site unless otherwise agreed with the determining authority and consultees. 59 For developments of 5 turbines or less, the ZTV can be calculated from the centre of the site. 60 ZTV overlay should extend to the edge of the map base containing the study area.

51 Presentation 82,86 Present ZTV maps in paper form. Production of ZTV maps in paper and of ZTV digital form, with varying visibility bands distinguished as separate layers upon a base map that can be interrogated using imaging editing software or GIS. 66 Overview ZTV map at 1:250,000 based on 1:250,000 OS map

66-67 Detailed ZTV map(s) at 1:100,000, Detailed ZTV map(s) at 1:50,000, based on a 1:50,000 OS map. based on a 1:50,000 OS map. Where these are provided as separate sheets there should be an Detailed ZTV mapping covering overlap of at least 1km between specific areas at a more detailed scale neighbouring maps (numbered and where there are particularly sensitive keyed). There may also need to be visibility issues. an overlapping site-centred map. 68 The base map should be very clear and printed in 'greyscale'.

69 Each individual turbine should be clearly marked upon the ZTV. Reference should be made to a plan contained within the ES which shows the individual turbine numbers and grid coordinates. 73 Colour overlays upon the ZTV map representing visibility should be partially transparent and allow clear visibility to the underlying base map. 75 For legibility, a maximum of 7 colours/ shades should be shown overlaid upon a ZTV map.

74-76 Colours for overlays should be bright and strongly contrasting. Their choice should take into account typical variation in computer screen and printer reproduction, and consider legibility for colour blind persons. 75 If visibility bands are used, there If varying visibility is distinguished, it is should be a maximum of 7 bands useful to also produce this information 79-82 and, if equal banding is not possible, digitally, arranged as separate layers the widest range should apply to the upon a base map in imaging editing lower end of the scale. software or GIS. 83 Information on the data and assumptions that have been used during the ZTV production as in Table 4. This information should be included within the VIA (or referenced appendices). 84-85 Maintain the format of the ZTV map Include ZTVs representing design throughout the VIA process if development within appendices of VIA. possible, so that comparisons can be made as the scheme develops. 69 The location of viewpoints (numbered) should be shown on the ZTV.

52 3 Viewpoints

88 The term viewpoint is used within Visual Impact Assessment (VIA) to define a place from where a view is gained and represents specific conditions or viewers (visual receptors). During the VIA process for a proposed windfarm, a number of viewpoints are chosen in order to assess:

• the existing visual resource; • the sensitivity of this resource to windfarm development; • the proposed design (incorporating mitigation measures to minimise any adverse impacts); and • the predicted appearance of the final proposed development.

This section of the Good Practice Guidance will address the selection of viewpoints and the information that should be provided for them.

89 It is important to stress that viewpoint assessment forms just one part of VIA. Because of the ‘powerful’ nature of viewpoint images and the widespread recognition of some of the locations from where these are taken, there is often over-emphasis of their role. But VIA also includes assessment of the following:

• the extent and pattern of visibility throughout the study area (thus considering those areas from where a windfarm will not be seen, as well as those areas from where it may); • views of the proposed windfarm from areas of potential visibility other than the selected viewpoints; and • sequential views.

90 The viewpoints used for VIA must be carefully selected to be representative of the range of views and viewer types that will experience the proposed development. They should also form part of the “description of aspects of the environment likely to be significantly

53 affected by the development” (PAN58 , paragraph 65).

91 In addition to representative viewpoints, specific viewpoints may also be chosen for their importance as key viewpoints within the landscape. Examples are local visitor attractions, settlements, routes valued for their scenic amenity, or places with cultural landscape associations. These will be supplementary to the range of representative viewpoints and will usually be identified through consultation with the planning authority and SNH, although they may be confirmed also by local people and special interest groups at public meetings and/or exhibitions.

92 The following issues regarding viewpoints are considered within this section of the Good Practice Guidance:

• Number of viewpoints Selection of viewpoints • Viewpoint siting

Use of viewpoints

Recording viewpoint

information

Good Practice Guidance

summary

54 Table 6: Uses and limitations of viewpoints (numbers in brackets refer to paragraphs in text)

USES OF VIEWPOINTS LIMITATIONS

• Carefully chosen viewpoints enable representation • Whilst the choice of viewpoints is very important, it must of a diverse number of views within a study area. be remembered that VIA should also be based on other aspects. An over-heavy emphasis on viewpoint selection • Carefully chosen viewpoints enable representation and assessment may create the erroneous assumption of a diverse number of viewers who experience the that this is the only aspect of VIA (89). landscape in different ways (90,98, Table 7). • There may be a tendency to focus on the particular • Viewpoints enable consultees to assess specific characteristics of specific viewpoints, rather than views from important viewpoints for example considering these as being just broadly representative of tourist attractions, mountain tops and settlements a wider area. Consequently, it is usually inappropriate to (91, 101). make design modifications to change the visual effects of the proposed windfarm from a single viewpoint. This is • By considering a range of views at different because this may have negative 'knock-on' effects a small viewpoints, the designer can consider how the distance away or from other viewpoints. Rather, a more windfarm image varies in appearance, informing holistic approach should be adopted that considers the design development (100). overall windfarm image from separate viewpoints in relation to the design objectives. • Views from numerous viewpoints can be assessed to determine sequential effects that occur as one • A point, and thus viewpoint, is by its very nature static moves through the landscape. whilst views tend to be experienced on the move as well as when stationary. • By assessing viewpoints in combination with ZTV maps, it is possible to consider the potential • Some viewpoints may be difficult to access and require pattern of visibility for a windfarm in 3 dimensions. lengthy walks to reach them. As a result, some people might not be able to assess the viewpoint on site. They will therefore need to rely on the landscape architect or experienced specialist assessor’s assessment and visualisations to indicate predicted visual effects.

• On account of the limitations of DTM data, several provisionally identified viewpoints may need to be visited before finding a location that is suitable to be a VIA viewpoint.

• Information on the exact location and conditions of individual viewpoints is required to be able to create accurate visualisations (111-112).

• Some requested viewpoints might be judged inappropriate due to unacceptable health and safety risks (99).

55 Selection of viewpoints

93 Viewpoints are initially selected as being those places from where a proposed development is likely to be visible and would result in significant effects on the view and the people who see it (receptors). This is informed by the ZTV and other maps, fieldwork observations, and information on other relevant issues such as access, landscape character and popular vantage points. This data enables a provisional list of viewpoints to be developed that can be later refined through further assessment, consideration of provisional wireline diagrams and discussions with the determining authority and consultees such as SNH. Interested members of the public may also advise on sensitive local vantage points at public meetings and/ or exhibitions held by the applicant.

94 It is important to stress that, even though a ZTV is very useful in focusing upon those areas with potential visibility of a proposed development, the ZTV is only one source of information used to inform the selection of viewpoints. Over-reliance on a ZTV to highlight viewpoints can result in over-concentration on open locations with the greatest visibility of a site, often far from the proposed development. This may be at the expense of potential viewpoints where visibility is less extensive, but from where views of the site are more typical.

95 Nevertheless, during early consultations regarding the provisional list of viewpoints, it is useful if the determining authority and consultees are provided with a copy of the ZTV. In certain circumstances, a selection of provisional wireline diagrams may also be helpful to give an impression of possible impacts from viewpoints. It is important to highlight, however, that the LVIA information that will accompany the visualisations within the final ES, and thus inform their interpretation, will not usually be available at this early

56 stage. Consequently, a degree of caution should be exercised when circulating wirelines during this period.

96 During the initial stages of VIA, viewpoint wirelines are used to inform the design development of the proposed windfarm. Some of these viewpoints will be described and assessed within the main ES report; however others may ultimately be omitted, for example because they show very similar results to another viewpoint. Nevertheless, details regarding these original viewpoints should be included within the ES appendices if they have informed the design process. Likewise, during the VIA process, it may be found that some of the originally identified viewpoints will not actually have a view of the windfarm due to local screening or changes to the windfarm design. These should also be documented within the ES.

97 The issues discussed above regarding the selection of viewpoints highlight that a flexible approach needs to be adopted. This also reflects the iterative nature of VIA and the way in which parties will gradually become more familiar with a site and proposed development. Consequently, the developer must be aware that additional or alternative viewpoints may need to be considered throughout the VIA process if more information is required by either the landscape architect or experienced specialist assessor, or the determining authority and consultees.

98 The range of issues that influence the selection of viewpoints is listed in Table 7 below. The aim is to choose a representative range of viewpoints from where there is likely to be significant effects.

57 Table 7: Views and viewers to be represented through choice of viewpoints

View • Various landscape character types (separate and type combinations of type)

• Areas of high landscape or scenic value - both designated and non designated, for example National Scenic Areas, Areas of Great Landscape Value, Gardens and Designed Landscapes, Search Areas for Wild Land, tourist routes, local amenity spaces

• Visual composition, for example focused or panoramic

views, simple or complex landscape pattern

• Various distances from the proposed development

• Various aspects (views to the north will result in a very

different effect to those facing south)

• Various elevations

• Various extent of windfarm visible, including places where all the wind turbines will be visible as well as places where partial views of turbines occur

• Sequential along specific routes

Viewer • Various activities, for example those at home, work, type travelling in various modes or carrying out recreation

• Various mode of movement, for example those moving

through the landscape or stationary

99 The assessment of viewpoints should not involve unacceptable risks to health and safety – either to the LVIA assessor or to others who may wish to later analyse the viewpoint assessment on site, such as staff from the determining authority and consultees, or the general public. Examples of these situations could include viewpoints from motorways, railway lines, scree slopes or cliffs.

100 Viewpoints within the local area immediately surrounding the windfarm are particularly useful to understand and develop the windfarm layout and design.

101 In addition to representative viewpoints, specific viewpoints may also be important as key viewpoints

58 within the landscape, for example local visitor attractions, scenic routes, or places with cultural landscape value.

102 In identifying viewpoints, it is important to consider whether a cumulative Landscape and Visual Impact Assessment (CLVIA) is also required as part of the ES. If it is, the choice of all viewpoints should be informed by the cumulative ZTV as well as the individual ZTV. Although it is possible to add supplementary viewpoints as part of a cumulative VIA, it is preferable to use the same viewpoints for both the individual and cumulative VIA to enable direct comparisons to be made. Likewise, it is also useful to choose viewpoints already used for other windfarm LVIAs in the surrounding area. The use of these may allow direct comparisons and also assist the determining authority, consultees and the general public who are already familiar with these viewpoints. It is hoped that further guidance on CLVIA may be provided in the future.

103 As the VIA progresses, it is useful to consider how the appearance of the windfarm from the separate viewpoints would be best illustrated within the ES. Further information on the choice of visualisations is included within the section of chapter 4 on ‘Presentation of Visualisations’, paragraphs 242 to 265.

104 The reasons for selection or omission of viewpoints recommended by consultees, should be clearly justified and documented within the ES.

Number of viewpoints

105 The number of viewpoints for separate projects will vary greatly depending on how many are required to represent likely significant effects from the range of views and viewers of a development as listed in Table 7. As mentioned previously, the initial list of provisional viewpoints, will be high. This is necessary to enable identification of the required viewpoints

59 during the early stages of the VIA, and to ensure no key viewpoints have been omitted. This process will involve the production of numerous wirelines too, as one will need to be produced for each viewpoint and for every layout and design option.

106 After reducing the number of viewpoints down to only those that are required to represent potential significant effects on views and viewers, it is common for there to be around 10- 25 viewpoints within a VIA in Scotland. However, this number will vary depending on the specific circumstances of a proposal. It is important to highlight that over- provision of viewpoints can be as unhelpful as under- provision. This is because an excessive number of viewpoints, for example including those that do not have significant impacts, may distract attention from the smaller number of viewpoints where impacts are significant. Additionally, a high number of viewpoints will also require more time to be assessed by the determining authority and consultees and result in a more expensive ES (in time, computing effort and graphic production) – both for the developer and people that wish to purchase the report. As a consequence, an appropriate balance must be struck through the VIA consultation process in terms of providing sufficient, but not excessive, numbers of viewpoints.

Viewpoint siting

107 Following agreement on the general location of viewpoints through consultation, the selection of the precise viewpoint site should be considered carefully. If, on visiting a potential viewpoint, it is apparent that there will be no view of the proposed development, for example due to localised screening, this location should be amended or withdrawn.

60 Figure 16: Deliberate positioning of distracting or screening features within a photograph

a: b:

c: d:

e: f:

These photographs were all taken within 50m of each other and all show essentially the same distant view of an existing windfarm, with only the foreground detail differing. a shows the view seen adjacent to a house. b is from the public road immediately outside the house. c, d, e are successively more open views from the same road. f is from the road verge adjacent to the tree visible in the middle of a.

If the purpose of the viewpoint is to illustrate the view61 from one specified important view, one window in a house perhaps, then it should include whatever foreground obstruction happens to be in the view, as in a above. Otherwise, if a viewpoint is to represent potential views from a locality, then it should be as unobstructed as possible, as in f above. 108 The siting of viewpoints needs to balance two key factors:

• the likely significance of impacts; and • how typical or representative the view is.

For example, in choosing a viewpoint along a stretch of main road, the magnitude of impacts may be greater along one section, but the likelihood of focusing on the view, that is its sensitivity, greater in another, for example at a lay-by. In all cases, judgement needs to balance these factors and this decision-making process must be documented. Most importantly, the location chosen must avoid the view of the windfarm being misrepresented by the inclusion of atypical local features, such as a single tree in the foreground, as illustrated in figure 16. Where this has mistakenly occurred, the viewpoint location should be revised and the photographs retaken. Conversely, it is also unacceptable to wander too far from the most prominent viewpoint in order to avoid typical foreground objects, for example moving into a neighbouring field when the view is intended to be from a road, in order to avoid the inclusion of the roadside fence or hedgerow.

Use of viewpoints

109 Viewpoints are used within VIA as sample locations from where to assess the existing visual resource, the design and siting of the proposed development, and potential visual impacts. Further information on their use is included within the Guidelines for Landscape and Visual Impact Assessment produced by the Landscape Institute and Institute of Environmental Management and Assessment (2002).

110 Viewpoints are primarily used for carrying out VIA. However, it is usually considered expedient to record elements of the landscape assessment at the same time, especially in relation to the landscape experience, as there is often significant overlap

62 between landscape and visual impacts. Where this takes place, however, it is very important to distinguish clearly between the information used for the VIA and that recorded for the Landscape Impact Assessment (LIA) to avoid confusion between the two.

Recording viewpoint information

111 It is important to record the field conditions in which a viewpoint is assessed, including information as listed in Table 8 below.

Table 8: Viewpoint information to be recorded no Viewpoint Specification required 1 Precise location 12 figure OS grid reference, measured in the field, ideally using GPS or a large-scale map. 2 Viewpoint altitude and Viewing Viewpoint altitude in metres height above Ordnance Datum (m AOD) (May be better interpolated from map or DTM than relying on GPS height). Viewing height in metres. 3 Nature of view Horizontal field of view (in degrees). Conditions of assessment 4 Date of assessment 5 Time of assessment 6 Weather conditions and visual range

112 This information is essential to allow others to visit precisely the same viewpoint and make on-site checks or assessment. It also helps others to understand the conditions under which professional judgements have been made.

113 As part of VIA, viewpoint assessment will involve recording baseline conditions 360˚around the viewpoint. However, most attention will be paid to the main focus of the view and its setting, the direction of the proposed windfarm, and any other existing and proposed developments.

63 114 All viewpoints should be numbered and their location shown upon separate maps as follows:

i The ZTV overview map(s) based upon a greyscale 1:50,000 OS base. The viewpoints should be marked using discrete symbols and numbering to avoid obscuring or confusing the ZTV information.

ii The detailed ZTV map(s) based upon a greyscale 1:50,000 OS base. The viewpoints should be marked using discrete symbols and numbering to avoid obscuring or confusing the ZTV information.

iii A detailed map extract on each viewpoint visualisation sheet which indicates the location and direction of the view on a 1:50,000 or 1:25,000 OS base map (although not necessarily the proposed windfarm), potentially reduced to another ‘standard’ scale, to enable those assessing the view on site to locate themselves in relation to local landscape features.

115 Viewpoint numbering needs to be clear. It is recommended that the original viewpoint numbers are retained right up until the point at which all the viewpoints are finalised and agreed and the VIA has been completed, to keep track of which viewpoints have been added or withdrawn during the VIA process. At this point they can be re-numbered in a continuous and more logical manner. Where material developed during the early stages of the VIA process information is included within the ES and its appendices, to show the development of the VIA, this should show both the original and new numbering so these can be easily cross-referenced.

116 To ease legibility, viewpoint numbering should follow a clear system. Some people number viewpoints in order of distance from a development, which is useful

64 when considering the effect of distance on impacts, while others number a windfarm in relation to how it tends to be experienced, such as from key routes, leading to isolated vantage points, which is useful when considering sequential impacts. Alternatively, numbering in a set direction, such as clockwise, may be the most appropriate method in terms of being clearly objective and transparent. Of these options, all are acceptable as long as the system chosen is clear and described within the VIA.

65 Table 9: GOOD PRACTICE GUIDANCE SUMMARY

VIEWPOINTS

Paragraph Minimum requirements Preferred requirements in report

Selection of 90 Choice of preliminary viewpoints to be viewpoints based on likely significant effects and 93 the ZTV, landscape character and landscape experience. The justification for these viewpoints (in terms of what they represent or illustrate) should be stated.

93 Assess each preliminary viewpoint against ZTV and wirelines.

93, 95 Consult on viewpoint choice with Wireline diagrams may also be determining authority and consultees. provided for each preliminary 97, 103 Requests for comments should be viewpoint to inform the consultation accompanied by a list of the proposed process. viewpoints, justification for their inclusion/removal and a ZTV (also cumulative ZTV if relevant).

96, 103 Include information on all preliminary viewpoints, whether they are subsequently abandoned or not. Information on those that have been dropped should be included within an appendix to the final LVIA/ ES report.

97 Adopt an iterative approach to viewpoint selection. Further/ alternative viewpoints may need to be assessed later in the VIA process if particular sensitivities become apparent.

98 Select viewpoints to represent different view types and viewer types as listed in 101 Table 7. Specific viewpoints that are important viewpoints of the landscape, for example designated sites and visitor attractions, and from which impacts are likely to be significant, should also be included.

102 Consider whether a Cumulative LVIA will If other LVIAs have been carried out be necessary. If so, viewpoint selection in the study area, it may be useful to should also be informed by the use some of the same viewpoint Cumulative ZTV. Cumulative locations. assessment should occur at every viewpoint that cumulative visibility occurs.

66

Selection of 105 The number of viewpoints should be viewpoints based on the number needed to (continued) 106 represent likely significant visual effects within the range of views and viewer types listed in Table 7.

107 Determine viewpoint siting and orientation to represent typical views that 108 are likely to result in significant visual effect within an area and reflect the key existing foci. Very localised screening/ distracting elements should be avoided if these are atypical of the area.

Use of 109 Consult GLVIA for use of viewpoints viewpoints

110 Distinguish between aspects of VIA and LIA at viewpoints

Recording 111-114 Number all viewpoints. Record viewpoint information on each viewpoint and the information conditions of assessment as listed in Table 8.

114 Viewpoint locations should be shown on the ZTV maps.

114 For each viewpoint, a plan showing its detailed location and direction upon the visualisation figures. This should be at 1:50,000 or 1:25,000, based on OS base maps of these scales

115-116 Viewpoints should be numbered in a logical order

67 68 4 Visualisations

117 Visualisations are illustrations that aim to represent an observer's view of a proposed development (figure 17). At the moment, visualisations of windfarms most commonly comprise photographs, computer generated wireline diagrams and photomontages. However the range and use of different visualisations will change over time.

118 Visualisations are very powerful in communicating information – ‘Pictures speak louder than words’. This means that people often jump to the visualisations within an ES to gain an impression of a scheme, in a way that they rarely adopt for other specialist information. However, it is important to stress that visualisations in fact represent just one source of data that informs a VIA.

119 A considerable amount of debate on visualisations in the past has revolved around making them ‘true to life’. However, it must be stressed that this is impossible. Visualisations, whether they are hand drawn sketches, photographs or photomontages can never exactly match what is experienced in the field. Thus, in contrast, this guidance concentrates on how visualisations should be produced to be most effective as a tool to inform the assessment of impacts. Ideally this assessment would always occur on site, where the visualisations can be compared to the ‘real life’ view. However, it is acknowledged this is not always possible. It is important to stress that, whatever the circumstances, interpretation of visualisations will always need to take account of information specific to the proposal and site, but which cannot be shown on a single 2-dimensional image, such as variable lighting, movement of turbine blades, seasonal differences and movement of the viewer through a landscape. Therefore visualisations in themselves can never provide the answers, only inform the assessment process by which judgements are made.

69 120 The production of computer generated wireline diagrams to inform viewpoint assessment by landscape architects and experienced specialist assessors on site has generally involved little dispute, and independent assessors have found in the past that the judgement of impacts based upon these has been largely accurate (University of Newcastle, 2002). However the presentation of photomontages to illustrate visual impacts to a wider audience within ESs has often been a contentious issue. Partly, this has been because the method, format and quality of these visualisations has varied considerably between ESs as different methodologies have been explored and adopted, but also because the decision-making process behind their choice has not always been clear.

121 It is important to highlight that this Good Practice Guidance tackles this issue from first principles – that of what, why, how and for whom visualisations are produced. Thus, while it builds upon the findings of the report ‘Visual Assessment of Windfarms: Best Practice’, by the University of Newcastle (2002) (see Introduction and paragraphs 8-9), this guidance is not based on adopting certain methods simply out of convention.

122 This section of the Good Practice Guidance considers the selection, creation, use and presentation of visualisations and will highlight the following key issues:

70 Key issues affecting visualisations

• Objectives • Field of view • Choice of camera • Choice of film Photography • Choice of lens • Time of day, direction of sun and weather • Information to record at each photo location

• Scanning Photographic post- • Panorama construction processing • Turbine Image • Image enhancement

• Use of wirelines • Data Wirelines • Geometrical properties • Drawing style

• The use of photomontages • Rendering of photomontages • Accuracy of match to photography Photomontage • Accuracy of lighting • Associated infrastructure and land use change

• Wirelines superimposed on photographs Other visualisation • Coloured 3D rendering techniques • Hand drawn illustrations • Animation

Choice of visualisation

• Presentation for different audiences and uses • Combinations of visualisations Presentation of • Viewing distance visualisations • Information to provide • Paper and printing • Exhibition display

Good Practice

Guidance summary

71 Key issues affecting visualisations

123 Photographs are important visualisations, not only in their own right, but also as a component of other visualisations such as photomontages. Photography is discussed in some detail in this section and also within the Technical Appendices. To understand how photographs represent what we see, it is important to first highlight that the eye is not directly sensitive to the outlines of objects or details in a scene. Instead it relies upon a degree of contrast to make those edges, and therefore the objects they define, visible. Thus there is always a trade-off between detail and contrast. This effect is replicated in photography, where visual representation on screen or the printed page is affected by the resolution of the image (to ensure that sufficient detail is captured) and contrast in the image (to ensure that the detail is visible). A key limitation of photographs in replicating the visual experience is that it is generally impossible to reproduce the full contrast range visible in a scene to the human eye. This means that while, on a bright day outdoors, we may experience a brightness ratio of 1000:1 between the brightest and darkest shades, a good quality computer monitor is only likely to achieve a ratio of about 100:1 and a printed image is only likely to manage 10:1.

124 Having chosen a specific camera, the key factors that determine the size of a visualisation are the selected field of view and viewing distance. These factors should be determined on the basis of being able to clearly represent the key characteristics of a view while the visualisation can be viewed comfortably. The resulting image also requires to be large enough to show sufficient detail.

125 It is important that visualisations are viewed at the correct ‘viewing distance’ – that is the distance between the eye and the image that directly relates to the visualisation calculations and image size, as shown in figure 18. In the field, the correct viewing distance

72 is easy to establish, as a viewer can adjust the position of a hand-held visualisation until it appears to correspond with the scene beyond. Very simply, if the photograph is held too close to the eye, the elements in the scene will appear too big; if it is held too far away, the elements will appear too small; and there is only one distance at which the photograph will match the real scene (the correct viewing distance). Unfortunately however, this direct correlation between the printed visualisation and real view is not possible if the viewer is not in the field at the viewpoint location; it is in these circumstances that use of the correct viewing distance is crucial if the visualisation is to be viewed and assessed correctly. The geometrical principle of correct viewing distance is explained in more detail within Appendix A.

Figure 18: The relationship between image size, viewing distance and the ‘real-life’ view

increased viewing distance

Using a standard paper size, a projected wind farm image will be smaller at a shorter viewing distance, and larger at a further viewing distance. However if held at the correct viewing distance they will be seen as being the same size. This represents a direct mathematical relationship between the eye and the image of the subject (the landscape).

A key issue is whether this viewing distance is comfortable for the viewer and if this is likely to be used correctly.

126 Not only must the viewing distance be correct, but it must also be set at a comfortable distance. For material printed in an ES and intended to be hand held, this should be between 300mm and 500mm, although a distance between 400mm and 500mm is recommended as a “comfortable viewing distance for

73 larger images at either A4 or A3 [and presumably larger] held at arm’s length “ (University of Newcastle, 2002). It also allows easier comparison with the real- life view on site as shown in figure 35.

127 Field of view is discussed in further detail within the section of this chapter on photography, paragraphs 135-144, and within appendices A and D. Although it would be convenient to be able to recommend a standard field of view to be used for all visualisations, analysis on site and of existing ESs suggests that no such standard can be established. Rather, the recommended horizontal and vertical field of view will vary, depending on what is required to illustrate the key characteristics of the visual resource and the key components of the proposed development. In some cases, the recommended horizontal field of view may conveniently fit the dimensions of a single photographic frame. More commonly, however, this requires a panorama photograph (discussed further in paragraphs 172-175 and Appendix B). In most cases, the recommended vertical field of view will conveniently fit within a single frame height (horizontal or vertical orientation); however, in exceptional circumstances, multiple vertical images could also be required in this dimension.

128 In the past, people sometimes doubted the technical accuracy of photos and photomontages as they didn’t seem to compare well to the scale of landscape features when directly compared on site. As discussed within the sections on image size (paragraphs 129 and 248) and viewing distance (paragraphs 125-126 and 255-256), while the visualisations were mathematically correct, they were often produced in a format that could not be used comfortably, and thus tended to be used incorrectly. People sometimes assumed that this deficiency would be corrected by taking photographs with a telephoto lens or equivalent. However, as discussed within the section on choice of lens (paragraphs 150-158) and

74 illustrated in figure 21, it is important to realise that a longer lens length does not necessarily result in a larger or clearer image; rather, the key factors directly influencing this are image size in direct relation to viewing distance and field of view (assuming good quality resolution and contrast).

129 The image height and width will relate to the viewing distance and vertical and horizontal field of view chosen. However, if a short viewing distance and a small vertical field of view is selected, the resulting image may not be large enough to show sufficient detail. To avoid this situation, the University of Newcastle (2002) stated that “an image height of approximately 20 cm is therefore to be preferred”. However, following the University of Newcastle’s own recommendations in terms of a minimum viewing distance of 300mm and the use of a 50mm equivalent camera lens, the maximum vertical height of an image generated from a horizontal format photograph (landscape format) would be 140 mm. Once cylindrical projection (discussed in Appendix B) is applied this is further reduced to 135mm at the edges and may be further reduced if the image was cropped in scanning. Thus, while an image height of approximately 200mm is recommended, an image height over 130mm is considered acceptable.

130 Visualisations are complementary to ZTVs and vice versa and neither can be interpreted satisfactorily without the other. While a ZTV shows where a proposed windfarm will or will not theoretically be seen (subject to surface screening) and the number of wind turbines (or parts of turbines) likely to be seen from any location, it cannot indicate what the windfarm will look like. A visualisation, on the other hand, simulates the appearance of the windfarm from a particular location, but gives no indication of whether this is characteristic of views over a wider area or peculiar to a specific site. Used carefully together,

75 a ZTV and a set of visualisations can provide information on all of these aspects.

131 The choice of visualisations for a specific viewpoint will depend on a number of factors described within the sections on choice and presentation of visualisations, paragraphs 232 to 265.

Table 10: Uses and limitations of visualisations (numbers in brackets refer to paragraphs within main text)

USES OF VISUALISATIONS LIMITATIONS

• Visualisations give an impression of the • Visualisations provide a tool for assessment, an appearance of a proposed windfarm (117). image that can be compared with an actual view in the field; they should never be considered as a • Applied carefully in the field, a visualisation can substitute to visiting a viewpoint in the field (204). be used as a tool to help assess the likely visual impact at that point. • Neither photographs nor visualisations can convey a view as seen in reality by the human eye. It is • Visualisations can aid development of the very difficult to represent contrast upon the printed windfarm layout and design (188). page. (119, 134, Appendix C).

• Presented carefully, visualisations can help • Visualisations are only as accurate as the data used illustrate to a ‘lay’ audience the location and to construct them (189-191). nature of a proposed windfarm (and may be the basis on which this audience will assess a project). • Visualisations can only represent the view from a single location and the ZTV and site visits must be • Wirelines provide objective data, while used to determine whether or not it is typical of a photomontages present an illustration of visual wider area. impacts that incorporates artistic interpretation. (186, 236-237). • Visualisations are inherently limited in the field of view and detail they can represent.

• Visualisations with very wide panoramic fields of view can be difficult for some people to use and interpret, while visualisations with narrow fields of view may appear to present insufficient context (Table 15 and 135-144).

• Visualisations should be used in combination with other VIA tools, including a ZTV (130).

• Visualisations presented upon paper cannot convey the effect of turbine blade movement (119).

76 Photography

Objectives

132 Photography has two main roles in EIA. One is as a simple record and aide-mémoire of site visits and on- site assessment work. The other, on which this guidance focuses, is in producing visual material for inclusion in an ES.

133 Photography for presentation in conjunction with wirelines or other visualisations, or as the basis for photomontage, requires high quality specification. This is because the perspective geometry of the resulting photographic image is necessary in order to use a computer program to generate an image with exactly matching perspective. This in turn implies considerable care in the selection and use of appropriate photographic equipment and supplies.

134 Representing landscape conditions through photography (and thus photomontages) has its limitations and, while some of these effects can be ameliorated and/or compensated for by using presentation techniques discussed in the following section, other effects are less easy to counteract. One of the most significant difficulties of photographing windfarms, in contrast to other types of development, is that they often appear on the skyline where there is little contrast between the light-coloured turbines and a light-coloured sky. In these circumstances, while the human eye can distinguish, in bright outdoor light, a contrast range of around1000:1 or more (the brightness ratio of the lightest to darkest elements in the scene), a picture of the same view taken with a camera and shown on a computer screen will have a ratio of only about 100:1. This range of contrast is reduced to as low as 10:1 when printed on paper.

77 Field of view

135 The term ‘field of view’ is used to describe the height and width of a view as represented by an image. These constitute the horizontal field of view and vertical field of view and are expressed as angles in degrees. (The terms 'angle of view', 'included angle' and 'view cone angle' are equivalent but can be ambiguous in some contexts.)

136 There have been suggestions that the horizontal field of view shown in visualisations could be linked to the physical limits naturally seen by a human eye. However it is difficult to derive definite parameters in this way, as a human has an extreme horizontal field of view of about 200°, yet only the 6-10° that falls on the central part of the retinas of the eyes will be in focus at any one time. Thus a viewer moves their eyes and head around to see a view over a wide area. Further information on this subject is included in Appendix C.

137 As viewers typically direct their attention over different widths of view, the size of photograph required to represent a view will vary for different projects and viewpoints, depending on the key characteristics of a view that need to be included within the image (defined by the landscape architect or experienced specialist assessor on site), and the extent of the proposed windfarm which needs to be included.

138 Occasionally this information can all be incorporated within a small field of view, as discussed below, that may conveniently fit within one single photographic frame (representing 39 degrees using a 50 mm lens on a 35mm camera). More commonly for open landscapes in the UK, however, a series of frames will be required that are joined together to form a panorama image. Panorama construction is discussed in further detail in paragraphs 172-175 and Appendix B.

78 139 Although a viewer will move their eyes and head around a field of view, a central point can be identified, based on the key focus or foci of the view (existing and proposed) and where the eye typically ‘rests’. This should also be determined by the landscape architect or experienced specialist assessor on site while carrying out the VIA so that the visualisations can be centred on this.

140 To ensure that the photographs taken for each viewpoint (which may be taken by someone other than the landscape architect or experienced specialist assessor) are able to accommodate the required horizontal field of view, it is recommended that a panorama is taken from each viewpoint that includes the entire width of open view. This may be 360° for some viewpoints. For certain viewpoints, especially where there is a high vertical dimension to the view, as in mountain areas or close to vertical features (including proposed or existing turbines), it will also be advisable to prepare a panorama comprising of vertical ‘portrait’ frames.

141 For the narrow horizontal field of view contained within a single frame, the differences in geometry between single frame and panorama are not marked (see Appendix B for more details). Nevertheless, photographs should be clearly identified as either single frame or panorama if a mix of the two types is used. Figure 19 shows the comparison between a panorama and a single frame view of the same scene. The panorama includes context missing from the single frame view. The single frame is slightly wider than the equivalent central portion of the panorama. This is because the image scale increases with horizontal distance from the centre of the image in the case of a single frame, whereas it is constant in the case of a panorama.

142 In the section on visualisations (7.5) within ‘The Visual Assessment of Windfarms: Best Practice’ (2002), the

79 University of Newcastle recommends that “a full image size of A4 or even A3 for a single frame picture, giving an image height of approximately 20cm, is required to give a realistic impression of reality”. During the early stages of developing this Good Practice Guidance document, John Benson of the University of Newcastle explained that this recommendation derived from the need to promote larger sized visualisations to enable sufficient detail, clarity and longer viewing distances than conventionally used at that time, rather than promoting a particular field of view that would limit visualisations to single photographic frame dimensions or paper sizes. He acknowledged that this push to produce taller images and longer viewing distances, and the assumption that these would be limited to A3 page sizes, meant that the implications of accommodating the required horizontal field of view was not sufficiently considered at the time. Indeed, in 2002, few developers had submitted panorama images at the recommended viewing distances and image height, although a few had produced what they termed as ‘enlarged photomontages’ that happened to include just a single photographic frame and fitted an A3 page.

143 It has been suggested by some that familiarity with the traditional proportions of a single frame photograph (3:2) or television screen (4:3) means that these proportions of image might be preferred by the general public instead of a panoramic image. However, there is ever-increasing use of ‘unconventional’ formats in communication, eg ‘wide- screen’ computers and televisions, and common use of image software such as photo stitching to produce panorama photographs at home. So familiarity presents fairly weak grounds on which to base field of view criteria. By contrast, defining the field of view in terms of the specific characteristics of the visual resource and development proposal provides criteria that can be continuously applied in a transparent and methodical manner.

80 144 The field of view is one of two factors that determine how large a visualisation image will be when presented on paper (Table 14 and 15); the other being the viewing distance. It is likely that there will always be pressure to keep viewing distances low to limit paper size on wide panoramas, and to use longer viewing distances for larger images in order to take advantage of the greater levels of detail possible. These issues are discussed further in the section on Presentation of Visualisations, paragraphs 242 – 265.

Choice of camera

146 To take photographs for visualisations, the choice of camera and lens represents the first of a series of judgements that must be made in terms of choosing the most appropriate photographic equipment and processes. All these will determine the quality of the final images in the printed ES. This is discussed further in Appendix B. The geometry of the image must be known and be able to be matched on a computer and the detail captured must be sufficient to produce a reasonable image quality as finally printed.

147 In general, a high quality camera is required to produce satisfactory results for ES purposes because the lenses need to be of high quality both in terms of resolving power (the ability to capture detail) and in freedom from distortion. For film cameras, the minimum standard should be a good-quality 35 mm SLR, with manually adjusted focus and exposure settings, and with a range of good-quality fixed focal length lenses. For digital cameras, the ideal is again a SLR with a range of good-quality fixed focal length lenses. The use of compact zoom digital cameras is not recommended due to the distortion these create.

147 The construction of panoramic photos requires accurately levelled photographs. To achieve these, a tripod is absolutely essential, as is a spirit level, to set the camera accurately so that it is not tipped up or down, or to either side. Special tripod heads for

81 panoramic work are available. These have a built-in spirit level, levelling screws and an indexing mechanism to allow the direction of view to be set in fixed increments. These are quite expensive but can speed up photographic work and simplify subsequent panorama construction.

148 Panoramic cameras are available, which can shoot a panorama onto a long length of 35mm film or a whole roll of 120mm roll film. While appealing at first sight, these are generally less practical than the use of a sequence of frames taken on an ordinary film or digital camera and subsequently spliced together. Panoramic cameras are discussed further in Appendix B.

Choice of film

149 Choice of camera film is important for non-digital work. The grain and resolving power of the film will affect the quality of the finished images and the detail represented in them. Very fast film (ISO 400 and above) should be avoided, except when it is vital that photography has to be done in very poor lighting conditions, as these films tend to have a coarser grain structure than slower films and poorer resolution in low-contrast parts of the image. Rather, a good quality ISO100 film (or ISO 200 on days with poorer light) from a reputable manufacturer is recommended. Good quality amateur film is generally satisfactory and does not have the requirement for refrigerated storage that many professional films have. Very slow film (below ISO 100) can prove difficult to use on-site and, although its very fine grain structure can produce superb results, exposure times need to be quite long on all but the brightest of days, which sometimes results in blurring of grass and leaves in the wind. Colour print film is a better choice than slide film as a source for scanning, because it retains more detail in shadows than is often the case with transparencies.

82 Choice of lens

150 The camera lens forms an image of the scene in front of the camera on film or on a digital sensor. The longer the focal length of the lens, the larger will be the scale of the image. For good quality lenses, substantially free of distortion, the perspective is exactly the same. This issue is discussed further in Appendix D.

151 As a longer focal length lens projects a larger scale image of the scene on to the film or sensor, any Figure 20 element in the scene will, therefore, cover more film grains or pixels and will be captured in more detail than would be the case with a shorter focal length lens. However, because the scale of the image is larger, but the film frame size or sensor size remains the same, it is also true that a smaller field of view

(and thus context of a view) is captured. There is Image size is directly proportional therefore inevitably a trade-off between the field of to focal length. view and the resolution of detail as shown in figure 21. The use of a longer lens does not mean that an image, or elements within the image, will necessarily appear larger. Rather, this is a function of the field of view and viewing distance applied as discussed in paragraphs 124 and 125.

152 With 35mm film, a 50mm focal length lens has been found to be a good compromise (Landscape Institute & Institute of Environmental Management & Assessment, 2002). It does not present the very finest detail visible to the human eye, but nevertheless captures much of it and is sufficient for most purposes (see Appendix C). A longer focal length lens will capture more detail, but only at the expense of reducing the vertical field of view and therefore loss of foreground and sky. A shorter length lens would result in the converse – a larger field of view, but with reduced detail.

153 To increase the amount of foreground and sky visible, photographs may be taken in ‘portrait’ format. This is

83 particularly useful where there is a strong vertical component to a view, for example where there are steep mountains, or where wind turbines would appear very close to the viewer.

154 Appendix D includes a table that lists the various field of view dimensions that result from taking photographs with lens of varying focal length.

155 There are very specific circumstances where a telephoto lens may be useful to illustrate a windfarm; for example where this would appear in the far distance and against the sky. In these situations, it is difficult for a photograph to adequately show the presence of turbines against the sky, due to the difficulties of the photo picking up the contrasts of shade between the sky and the turbines as discussed previously in paragraph 134. In these circumstances, some compensation for the restricted range of shades may be possible with the provision of additional detail as provided by a photograph taken with a telephoto lens. However it is important to realise that the viewing distance for this telephoto view when printed will be much further than for the more conventional photographs based on the use of a 50mm lens (or equivalent) and thus may be difficult to view easily. In addition, a telephoto view will usually omit contextual information and thus should only be provided in addition to a 50mm lens (or equivalent) view for the same viewpoint.

156 The following photographs (figures 22a-22c) of the existing Dun Law windfarm show a comparison of effect using alternative lens lengths for an image of the same size but requiring varying viewing distance.

157 1If using a telephoto lens to take pictures, it is important that this is of a fixed length. For, while zoom lenses are convenient for general photographic use in allowing the view to be framed up in the camera, rather than by subsequent cropping, they are always an optical compromise. Their resolving power

84 is never as good as their equivalent fixed focal length lens and some geometrical distortion is almost always introduced into the image. The latter usually varies with focal length setting (see Appendix D). Also, other than setting a zoom lens at its upper or lower focal length limit, it is impossible to set it precisely to a given focal length, resulting in variations in focal length between viewpoints and difficulties in matching computer generated images.

158 Most digital cameras have a sensor area smaller than a 35mm film frame (although this is likely to change in time). So, although the image size will be the same for any given focal length, the digital camera has a smaller field of view. The only sensible solution to this problem is to use a shorter focal length lens, often a 28 mm lens, in order to achieve the required coverage. Even with a very good lens, this will introduce a small amount of barrel distortion (see Appendix B), which may be acceptable or can be corrected with appropriate image processing software. The use of a compact zoom digital camera is not recommended.

Time of day, direction of sun and weather

159 Key environmental factors affecting the quality of a photograph are the angle of the sun, the direction of the sun and the level of humidity (creating haze, cloud or rain). If a photograph is taken in fine conditions, the most important issue tends to be the direction of the sun, although low light can emphasise the vertical element of the landscape. Conventional wisdom states that the sun should be behind the photographer for the best lighting in a scene. In practice however, having the sun directly behind the camera can make some landform shapes less apparent and side lighting often gives the best impression of the topography. Looking directly into the sun, especially in the winter when it is low in the sky, is to be avoided, unless sunset views need to be illustrated.

85 160 Whilst it is appropriate to consider a range of weather conditions in the VIA, the viewpoint photographs should be taken in weather, visibility and lighting conditions that would allow operational wind turbines to be captured on a photograph (which requires greater light intensity, clarity and contrast than when viewed with the naked eye). This is more likely to be achieved by maximising the contrast between the turbines and their background. This requires taking account the effect of lighting, background and turbine colour as shown in Table 11 below. Table 11 indicates how the optimal lighting will also vary with turbine distance. The actual distance will depend on the brightness of the light, the focal length of the lens used and the resolution of the film and printing technology.

161 It is rarely possible to achieve the desired photographic contrast in grey and overcast conditions, unless the turbines would be back-lit or in shadow. Land with heavy snow cover gives a background similar to brightly lit clouds and can present similar problems in achieving the required contrast.

Table 11 - Best weather and lighting for photographing turbines

Turbines Background Weather Ideal lighting

land Bright sunshine Front or side lit

Blue sky, bright sunshine Front or side lit Near/ middle distance

sky Cloudy, bright Back lit or in shadow

Dark storm clouds, bright sun Front or side lit

land Bright sunshine Front lit

Blue sky, with clouds Back lit or in shadow Distant sky Cloudy, bright Back lit or in shadow

Dark storm clouds, bright sun Front lit

Source: Kay Hawkins, E4environment Ltd and Phil Marsh

86 162 Realistically, it is not always possible to arrange for the photography from each viewpoint to be taken under ideal conditions when there is a tight project timescale. However, photographic expeditions should be planned (by reference to weather forecasts, web cams and local information) as far as is practical to coincide with good conditions, with visits to viewpoints to the east of the site in the morning, and to the west in the afternoon.

163 With wide panoramas, a variation of light across the image is inevitable. The critical issue is to ensure good lighting of both the proposed development site, and the key characteristics and features within the surrounding landscape that are most likely to be affected by the proposed windfarm. Where a panorama is to be produced from a series of frames spliced together, it is important to choose an exposure setting (shutter speed and aperture) that is appropriate for the most important part of the scene and to apply that exposure setting to all frames within the panorama.

164 Whatever the weather and light conditions, the minimum requirement is for photographs to clearly show the proposed windfarm site and its context and, if they are to be used as the basis for photomontage, they should be able to have wind turbines clearly illustrated upon them.

Information to record at each photo location

165 To assist with the construction of visualisations back in the office or studio, the photographer should keep a record of important information about the viewpoint location, equipment used etc, as listed in Table 12. This information is best recorded in a photo log for each photo point. The records of information within this log may be made by separate assessors and photographers on different days and, as a consequence, should be sufficiently comprehensive for both parties to understand the conditions under which

87 all visits occurred. Some of this information needs to be included on the final visualisation (see Table 16). Some photographers find it helpful to record the shutter speed and aperture settings used and, in the case of a digital camera, the ISO setting used (although this is usually all recorded in the EXIF data associated with each frame).

166 It can also be useful to take a photograph recording the position of the tripod location in relation to local features such as a cairn or signpost. This can be helpful both during the production of the visualisations and in the event that the location has to be re-visited.

Table 12 - Information to be recorded at each photograph location (in addition to viewpoint information listed in table 8)

• Camera type (SLR, digital)

• Lens focal length (for example 50mm)

• Film speed (for example 100 ASA)

• Frame numbers as read off the camera (although these may need to be calibrated with the negative numbers which may be different)

• Spacing between the frames (for example 30 degrees for 50mm shots)

• Compass bearings to distinctive elements in the view that will assist with the scaling and placement of the turbines (plus sketch of the view with these elements marked if appropriate).

Source: Kay Hawkins, E4environment Ltd

167 For compass bearings, it is more accurate to use a sighting compass, as bearings to within 0.5 degrees can be measured. However, sighting compasses do not have the variation adjustment (to compensate for the difference between grid and magnetic north). There is less risk of mistakes if the bearings are recorded in the photo log and recalculated back in the office to allow for the appropriate number of degrees deviation. Significant deviations in the compass bearings will be caused by nearby metal objects

88 (including passing vehicles) and, if this is a possibility, it should be noted.

Scanning

168 Assuming that all photographic preparation work will be carried out digitally for ES work, the next step in the process is to import the images into a computer system. With a digital camera, this is very straightforward and is done directly, with no risk of image degradation. However, with a film camera, a scanning stage is required. Scanning should be carried out using negatives rather than prints, as they retain a greater range of contrast than can be represented on photographic paper.

169 It is possible for an experienced professional to adequately scan from negatives on a relatively inexpensive flatbed scanner. Some of these will come with a range of settings for different film stocks while others will require some experimentation to obtain the best results. A true optical scan resolution of 2400 ppi (points per inch) is adequate for most purposes, giving a 3400 x 2267 pixel image from each 35 mm frame.

170 It is, however, difficult to keep the film as scrupulously dust-free as is desirable when scanning, and it is extremely laborious work. Both of these factors make it an attractive proposition to have the film scanned professionally. Many photographic processors offer this service and will provide a CD-ROM and a set of prints as a packaged service, which should ensure a good standard of cleanliness. However the quality of the scanning varies considerably. In particular, detail is often lacking in very light or dark areas of the image, so that features obvious on prints are hard to pick out on the scans. It is worth having test scans done before committing valuable photography to any of these services. Also, some cropping can occur and it can be difficult to ascertain precisely how much, which makes the calculation of, and scaling to, a chosen viewing distance difficult to achieve.

89 171 Although digital photography and scanning from 35mm negatives both produce digital photographic images, they are different. In the case of a digital camera, the sensor is accurately centred on the axis of the camera lens, so that the optical centre of the photographic image falls exactly in the centre of the digital image area. With scans from film, no matter how accurately it is done, there is always some residual misalignment, which is compensated for by slightly cropping the image. Because of this, the optical centre of the photographic image is not certain to accurately fall in the middle of the digital image, which means that some image processing operations cannot be reliably applied to them.

Panorama construction

172 Photographic frames are projected onto a plane surface to correspond to the plane of the film or sensor on which the image was first captured. A panorama involves the projection of frames onto part of a cylinder (see Appendix B for a discussion of these issues). It is possible to take a series of frames and to find the overlap point between each adjacent pair and then to splice them together. In this case, however, the frames correspond to a series of facets rather than a smooth cylinder. In consequence, straight lines, such as kerbs or rooflines, which run from frame to frame, appear to kink sharply at the panel joins. It is possible to improve this by using many very narrow panels, but cumbersome to do so.

173 A number of software packages are available to take a series of separate frames and combine them into a single panorama (software to do this often comes on the CD accompanying a new digital camera). Most of these programs attempt to do the whole operation automatically by trying to find matching elements in adjacent frames where they overlap. They also remap the image mathematically so that it forms a smooth cylindrical panorama and blend out any mismatches

90 in colour between frames. Unfortunately, even with the best software, the ability to carry out the image matching operation is not entirely reliable. Some programs allow the user to manually over-ride the splicing; others do not and will produce images unacceptable for professional use in an ES. There is always some residual mismatch at the joins between adjacent frames and the usual solution is for the overlap area to be blurred, to hide the artefacts created by the slight mismatch. Naturally, this also destroys valuable detail. As a consequence, the finished panoramas are never as geometrically accurate as ones which are created carefully using manual tools and therefore should not be used as the base image for photomontages.

174 Tools are available as plug-ins to image processing software which facilitate the creation of panoramas manually. Each frame should ideally first be corrected for any barrel distortion in the image (this step can only be done satisfactorily with an image from a digital camera as it must be applied symmetrically with respect to the optical centre of the photographic image). A remapping operation is then required to convert the planar geometry of the photographic frame to a cylindrical image. Once overlapped and spliced, the geometry will match consistently across adjacent frames without the kinks apparent without correction. Finally, the colours of each frame can be adjusted to achieve a uniform colour balance across the entire panorama.

175 In theory, as long as the component images used to construct a panorama cover the scene with no gaps, it would be possible to splice them together. In practice, some overlap is required. There are two main reasons for this:

• Some minimum overlap is necessary to see the same detail on two adjacent frames in order to align them accurately; and

91 • it is often useful to have some scope to choose which of a pair of adjacent frames is used as the source for a particular part of the image, for example to compensate for the effects of changing lighting or moving cloud shadows, to remove the effects of vegetation moving in wind or to remove moving vehicles.

Too much overlap, on the other hand, will increase the work involved in splicing panoramas. In general the overlap should be somewhere between one quarter and one half of the width of an individual frame.

Turbine image

176 The turbines shown on a visualisation should represent reasonably faithfully the shape of the intended turbines for a project. Ideally, they should be based upon detailed line drawings of the actual turbines proposed; but they should at least have the correct hub height and rotor diameter. This will allow the proportions of the turbines to be understood from the visualisation as well as confirm actual visibility. Some practitioners prefer to depict all turbines with the rotors set to have one blade pointing straight up, whereas others prefer these set at random angles, helping to simulate more realistically the fact that the turbine blades will be moving. The disadvantage of setting blades at random angles is the risk of ‘losing’ turbines behind the landform because the blade angle happens not to put a tip high enough in its arc to be seen. On the other hand, having all the blades at the same angle can produce a very ‘regimented’ effect that appears less realistic. Consequently it is recommended that, for all ‘working’ copies of wireline diagrams, turbines are always shown with one blade positioned straight upwards, while photomontages, as illustrations, can show turbines at random positions. However, even accepting the more illustrative quality of photomontages, it should be ensured that all the wind turbines that could potentially be seen from a

92 viewpoint are shown within the image, even if their highest blades are on the diagonal.

177 Turbines can be shown in three different ways:

• Every turbine individually facing the viewpoint; • Every turbine facing the same direction, but this varying between viewpoints so that the ones in the centre always face forwards towards the viewpoint; and • Every turbine facing the direction of the prevailing wind at each viewpoint.

178 Some software can only show the turbines facing the viewpoint as it uses a 2-dimensional representation of the turbine, but most offer a choice. It is often stated that a wind turbine is most visible when seen ‘face on’, and therefore this should be represented as the ‘worst case scenario’. However, when ‘face on’, the wind turbine image can actually appear more simple and comprehensible than when it is seen at an oblique

Figure 23: Variable direction of wind turbines

Turbines all facing into the wind, as would be seen from the viewpoint

View to North

View to View to North West South West Viewpoint

Wind from South

93 angle, so the latter can actually result in similar levels of impact. The key issue to highlight here, once again, is that visualisations are tools, and that they can only represent the likely effect of a development at a particular time. Thus, the most important objective should be to present an honest representation that informs the viewer’s prediction of how the turbine rotors would appear in different conditions.

179 To meet this objective, the first option for turbine direction listed in paragraph 177 above is not recommended; this is because this image would in reality rarely occur over a wide horizontal field of view and would thus appear improbable. Both the second and third options are acceptable. The presentation of turbines facing the prevailing wind will tend to create the most realistic image throughout an ES. If all the wind turbines face the same way, but in an alternative direction, this is equally accurate. However the choice of direction may be questioned where there are numerous windfarm developments visible over a wide field of view and the choice of direction seems to favour illustration of one windfarm more than another.

Image enhancement

180 Enhancement of images is an inherent part of photographic production. Photo processing involves judgements - there is no process by which a ‘pure’ photo can be produced without the application of human decision-making, from exposure timing to the specification of the camera, and whether this is applied manually or automatically.

181 Although enhancement, for example to maximise clarity, has traditionally occurred within the photographic darkroom, this practice has often raised concern with regards to producing digital photographs and photomontages. This may be because it is difficult to quantify the level of enhancement in a way that is easy to understand, raising the suspicion that an image has been ‘doctored’, and is consequently

94 Figure 24: Various levels of image sharpening

Digital photograph contrast enhanced and colour balanced

Sharpened for printing

95

Grossly over-sharpened Figure 25: The effect of colour balancing an image

Digital photograph as taken

Blue cast removed by colour balancing

96

Contrast and brightness enhanced misleading. In reality there is no way to avoid a photograph being ‘doctored’ as this is an integral part of photograph and photomontage production. The only way to ensure that this is to acceptable standards, is to require the use of extreme care by a suitably experienced professional. The extent of enhancement must also be limited to that which would conventionally occur in a darkroom to improve the clarity of an image, not change its essential character. For example, it is important that any enhancement, such as sharpening elements within a view, is carefully balanced throughout an image, not just the wind turbines; otherwise other features may seem less prominent in comparison.

182 Sharpening an image slightly can also help fine detail visible in the field, be visible on printing. This operation works by identifying areas of high contrast in the image, which correspond to the detail we see, and locally further increasing the contrast so that the detail becomes more apparent. However this operation must be applied carefully as over-sharpened images can result in a hard dark line that appears at the skyline and a corresponding light edge to the sky above it, while miniscule details can appear unrealistically prominent and fussy (see figure 24).

183 It is also helpful to sometimes adjust the brightness and contrast of an image so that, for example, no detail is unnecessarily lost in deep shadow, while also ensuring that the sky does not bleach out to white or pale grey as the shadows are lightened. Colour balance across the whole image sometimes needs adjustment, even if the photography was taken in good conditions, to remove unwanted colour casts (see figure 25). These operations are available in photographic image processing software and are techniques similar to those used within a conventional darkroom. They do not change the content of the image.

97 184 Conversely, if changes are made to sky colour alone, which is sometimes done to ensure that turbines are visible, the content of the image is effectively changed. This approach should therefore only be employed if there is no other practical alternative and targeted enhancement is clearly noted adjacent to the affected images. In these circumstances, it may be advisable to ensure that the original photographs are available, if required, to demonstrate the degree and nature of the enhancement that has taken place. However, as discussed in paragraphs 180-181above, it must be understood that even the original photographs will have been enhanced to some extent through standard photo processing.

Wirelines

Use of wirelines

185 Wirelines are computer generated line drawings, based on a digital terrain model (DTM), that indicate the three-dimensional shape of the landscape in combination with additional elements. They are a valuable tool in the windfarm VIA process as they allow the assessor to compare the position and scale of the turbines within the wireline to the existing view of a landscape.

186 Wirelines are particularly useful to the landscape architect or experienced specialist assessor as they strictly portray objective data. This means that, by comparing wirelines with a view on site, the assessor can make clear and transparent judgements on the likely visual impacts in a variety of environmental conditions, safe in the knowledge that the wirelines have not been subject to manipulation that cannot be quantified. They can also reveal what would be visible if an existing screening element, for example vegetation or a building, is removed.

187 It is important to highlight that wirelines are not intended to portray a ‘true to life’ visualisation of a

98 proposed windfarm. Rather, their use in VIA relies on interpretation that is based on experience of the visual impacts of windfarms and how these typically compare to the representation of a windfarm within wireline diagrams.

188 Wireline diagrams are extremely valuable in the windfarm design process, as they are relatively quick and easy to produce, so that many sets will usually be generated as a windfarm layout evolves. The benefit of these wirelines is that, not only do they clearly convey the overall windfarm image that results from the layout and siting, but they also show how this is affected by the position of individual wind turbines, that can be easily identified and re-positioned in an attempt to improve the effect. The assessor will usually identify individual turbines using computer software. However, for the benefit of the ES reader, it is essential to include some wirelines within the appendices that have individual wind turbines numbered. This aids understanding of the design process, as documented with reference to individual turbine numbers, and also enables further mitigation measures in relation to individual turbines to be discussed more easily. A limitation, however, is that individual numbers for wind turbines may change during the design process, as wind turbines are added and removed. Consequently, when comparing recent wirelines to those produced in the early days of a project, some number correlation may be required.

Data

189 The accuracy of a wireline depends on the accuracy of the data used to create it. In general, this data will be the same as that used for calculation of the ZTVs, commonly the OS Landform Panorama or Landform Profile DTM products. See paragraphs 41-44 for a fuller discussion of these issues.

190 It is important that, for each project, sufficient DTM data is used to enable the full landform background to

99 the turbines to be seen and thus easily matched to a view on site or photographs of the existing landscape. For some views, DTM data may need to extend further than the LVIA study area because the distant horizon extends beyond this limit.

191 The quality of Landform Panorama varies widely across the country, largely reflecting the variable quality of the contours on the OS 1:50,000 scale First Series mapping which was used as a source in the late 1980s. Some narrow ridges and peaks are in particular not well represented and can produce wireline diagrams that do not closely resemble the scenes they are supposed to depict. In these cases, it is worth using the Landform Profile DTM, which is usually a better representation of the landform even if downsampled to 50 m simply for use as a ‘patch’ to repair the Landform Panorama DTM. In a few situations, the Landform Profile DTM may be found to give a poor representation of small but important local landform features. Some of the data, such as NextMap, now available using radar or laser based aerial survey techniques may be appropriate in this situation for critical viewpoints.

Geometrical properties

192 As is the case with photographs and photomontages, most wirelines used in windfarm ES work are Figure 26a: Planar perspective panoramas. Some software packages can produce true cylindrical panoramas directly; others will produce panoramas, but approximate them as a series of planar panels, generally with an option to specify how many panels are used. Provided that the individual panel width is kept to 20° or less, an acceptable match to a photographic panorama is usually achievable.

193 Some software cannot produce panoramas at all, only simple planar perspectives. The horizontal field of view can generally be specified (sometimes indirectly as an equivalent notional focal length) and will often

Figure 26b: Panoramic perspective allow very wide angles to be used. It is however very

100 Figure 27: The effect of earth curvature on wireline composition

Wireline image of DTM including effects of earth curvature and atmospheric refraction

This hill should actually be over the horizon and not visible

Wireline without earth curvature or refraction

Above images superimposed. The version with no101 curvature is shown in red. Note that distant hills are wrongly placed on the image and also some geographical features are shown which in reality are over the horizon. The image without earth curvature would be impossible to superimpose satisfactorily on a photograph. important to bear in mind that a planar perspective is not the same as a panorama (there is more detail on this topic in Appendix B). Panoramas can always be approximated with software like this by generating a series of panels that approximate to the required perspective, and then splicing them together in the way that would be done with photographs.

194 Software packages designed for depicting areas of terrain usually include the effect of earth curvature, whereas general-purpose CAD packages most often do not. As pointed out in paragraph 50, the effect of earth curvature increases rapidly with distance from the viewpoint and has a profound effect on the resulting view (figure 27). Wirelines constructed without earth curvature will at best be a poor match to photographs, and at worst will be seriously misleading, as they show features in the distance which in reality would be hidden below the horizon (see Appendix F).

Drawing style

195 Wirelines consist of little more than simple line- drawings of the DTM and the windfarm. However, there are a range of graphic styles used to depict these which can affect the clarity and legibility of the finished image. A number of options are acceptable; however it is important that the same format is used within a single ES.

196 The DTM is most commonly drawn as a mesh seen in perspective. While this is a faithful depiction of the landform as represented by the DTM, it can often result in the more distant parts of the scene becoming unreadable as the grid lines get closer together, eventually merging into solid colour. An alternative, offered by some packages, is to draw only the outline of the topographic features in the scene, approximating to the lines one might draw as a sketch of the scene (figures 28a and 28b). While this approach results in a less cluttered image and one

102 similar to that which might be hand drawn by a landscape architect or experienced specialist assessor, it can sometimes make the shape of some features harder to understand in three dimensions. A few packages offer a further option of drawing the outlines and also putting in the mesh in a different colour or lighter shade. While the options available within separate software packages may limit choice, it is worthwhile trying alternatives to see which works best for a particular project.

197 Colour is useful to highlight the wind turbines in contrast to the landform lines or mesh, especially in distant views where the effect of merging lines noted above often occurs and where some turbines may only just be visible against the landform. It is sometimes argued that this unnecessarily draws attention to the windfarm but, as the purpose of the diagram is to depict the geometrical relationship between the windfarm and landform, this is not a compelling argument. There are a number of options, such as those listed below and shown in figures 28a and28b.

• Green turbines on a black DTM; • Red turbines on a black DTM; • Black turbines on a grey DTM; • Blue turbines on a grey DTM; and • Grey turbines on a green DTM.

198 Using the same colour and/or shade for the turbines and DTM grid is not recommended due to the lack of distinction between them, as already discussed. However, all the other options listed above, and potentially others too, are acceptable with the caveat that care must be taken to ensure that the type of colouring does not produce an illusion that the turbines are closer than the landform on which they are sited.

199 Varying colours of turbines can be used to distinguish separate windfarms within a view or existing turbines from proposed wind turbines planned as an extension.

103 200 Turbines can also be numbered, as mentioned in paragraph 188, so that the individual turbines visible can be directly referred to a layout plan also showing turbines numbered. Unless the windfarm is a very small development, however, this information will usually take up a large amount of space upon the wireline image and, similar to any other labelling, may reduce clarity and distract from the wireline image itself. Consequently, it is generally preferable to label duplicate wirelines within an appendix (just a selection of key viewpoints may suffice). This labelling may need to be done manually, depending on the software used.

201 Features other than wind turbines, can also be modelled into the wireline, depending on the software being used. In this way, existing landscape features can be shown, such as pylons or distinctive buildings, which will help direct comparison with the photograph of the existing view (as long as these do not obscure the wind turbines). In addition, other elements of the windfarm development can be shown, such as the route of access tracks. Inclusion of reference objects, such as field boundaries can help the process of matching the perspective and the photograph during photomontage preparation (although these will usually not be desired in the final wireline used in the ES).

104 Photomontage

The use of photomontages

202 The basic concept of photomontage is simple; it combines a photograph of an existing view with a computer-rendered image of a proposed development. In this way, photomontages are used to illustrate the likely view of a proposed development as would be seen within a photograph (not as it would appear to the human eye in the field). However, it is important to stress that, although the scale, siting and geometry of photomontages are based on technical data, the other qualities of the image are open to judgements, albeit professionally informed, similar to a hand-drawn illustration. In addition, as already discussed in the section on photography in paragraph 134, photomontages are subject to the same limitations as photographs for representing existing windfarms; that is, that it is difficult to replicate their visibility to the human eye in the field because a printed image cannot replicate the same range of contrast. This is of particular importance when trying to see light-coloured structures at a distance against a background of similar colour and brightness.

203 Photomontages are not generally required by the landscape architect or experienced specialist assessor to carry out VIA. Instead, they will normally use wirelines while carrying out site assessment, to ensure their judgements are based on objective data, as described in paragraph 186 (although, in addition, they will usually consider all information available). However photomontages can help illustrate the visual impacts that have been assessed within the VIA to an audience that is less familiar with windfarm developments, the particular landscape in question and/or how windfarms typically appear in a landscape in comparison to their representation by wireline diagrams.

105 204 Although photomontages are based on a photo of the existing landscape, it is important to stress that they should never be considered as a substitute to visiting a viewpoint in the field. This is because they are only a tool for assessment. They provide a 2-dimensional image that can be compared with an actual view of the landscape to provide information, such as the scale of a proposed development, but they cannot convey other qualities of the landscape experience that can only be appreciated in the field.

205 Given the limitations of depicting turbines in photos or photomontages of the landscape (as discussed in paragraph 134), their production will usually be of most value for views within 15km of a windfarm site for turbines up to 130 metres high to blade tip. However this will depend on the specific windfarm design and environmental conditions and, consequently, this parameter should usually be discussed and agreed with the determining authority and consultees.

Rendering of photomontages

206 In order to address the difficulty of representing windfarms clearly within photos, it is common practice to exaggerate the prominence of the turbines to ensure that they stand out in the finished photomontage, as discussed previously in the section on photography image enhancement (paragraphs 180-184). When done poorly, this results in a level of visibility unwarranted by the conditions seen in the photograph. However, where done sensitively, this can improve the clarity of an image, comparable to the conventional processing of photographs within a darkroom. Consequently, as for the section of this guidance on photography, is recommended that the rendering of photomontages is acceptable if carried out extremely carefully by a suitably experienced professional. As a guide, the degree of enhancement should be limited to that which would conventionally occur in a

106 darkroom to improve the clarity of an image, without changing the essential character of the image. The nature of the enhancement should also be noted within the ES.

207 Where a project involves an extension to an existing windfarm, it has sometimes been the case that existing turbines have been ‘painted out’ in the photo of existing conditions and re-montaged back so that the images of both existing and proposed turbines match. This effectively changes the record of baseline conditions. Consequently, once again, this practice is not recommended if it can be avoided; however it is acceptable under exceptional circumstances, where carried out with extreme care by an experienced professional and noted within the ES.

208 Most importantly, enhancement and rendering cannot compensate for photographs that have been taken in poor light or weather conditions, for example the blue colouring of white skies because of cloud conditions at the time of the assessment. In these circumstances, the photos should ideally be retaken. Neither should enhancement be used as a way of making turbines appear visible within a photomontage for a viewpoint that is actually so far from the proposed development that existing turbines would not be visible within a photograph. In these circumstances, it would be better to represent the likely visibility of the development using wirelines.

Accuracy of match to photography

209 In order to create a photomontage, the geometry of the overlain rendered image of the windfarm must exactly match that of the base photography. That is, the viewpoint location, height and direction of the view must be identical, as must the horizontal field of view, and both the panoramic photograph and the rendered image must be true cylindrical panoramas.

107 210 The most reliable method of obtaining this accurate match is to generate a wireline image that matches the photograph. If the wireline can be accurately overlaid onto the photograph, then the fit is good. However, where there are few landform features, this process may require the matching of specific structures identified and mapped on site.

211 A GPS position, taken when the photography was carried out, is almost always sufficient for windfarm applications (viewpoint location errors usually manifest as a mismatch in the horizontal position of elements in the photograph and wireline and are always more apparent in closer objects or landscape elements). If it is impossible to obtain a simultaneous match on both near and distant landform features, then the viewpoint position is incorrect and will need to be either re- measured on site or worked out through iteration, depending on the magnitude of the discrepancy and the presence of identifiable objects in the scene.

212 Matching of photographs and wirelines can usually be satisfactorily achieved through knowing the exact location of the viewpoint and windfarm and then adjusting the direction of view to align distinctive features shown within these images. In certain landscapes, where there are few distinctive topographic features, it is necessary to use man-made features such as masts, pylons or buildings in addition. Even when features of these types are clearly visible in photographs, it is often difficult to identify them on the map. If it is anticipated that use will have to be made of built features, then it is worth noting these while taking the photographs and taking compass bearings towards them with a good quality sighting compass. Once identified, these features can be added to the computer model used to create the wirelines and then be treated as alignment aids like topographic features.

213 Note that it is not sufficient to take a compass bearing of the camera's direction of view and then to assume

108 that this will be sufficient to set the correct direction for a matching wireline.

214 Adjustments should be made until a satisfactory match between topographic features in the wireline and the photograph are achieved across the whole width of the panorama to ensure that there are no errors of scale. If this cannot be achieved, then the fields of view do not exactly match and the parameters must be adjusted further. It is often the case that a small rotation needs to be applied to the panorama to compensate for residual errors in levelling the camera.

215 Once a satisfactory match has been achieved, it is then possible to use the parameters for the wireline as perspective parameters for rendering the turbines for photomontage. Many packages combine wireline and rendering and some also include the facility to overlay the wireline on the photograph while adjusting parameters. However, the best quality is usually obtained using a separate computer program designed for high-quality rendering. Note that most rendering programs do not include the effect of earth curvature, so it may well be necessary to make vertical adjustments to the turbine positions accordingly before rendering.

216 The rendered windfarm should be overlaid on the photograph using a matched wireline for reference, to ensure that the position is correct.

Accuracy of lighting

217 The lighting model used to render windfarm images for photomontages should be a reasonably faithful match to the lighting visible in the base photograph. Consequently it is recommended that the date and time that the photographs were taken should be recorded by the photographer/assessor to enable an exact sun direction to be calculated although, in practice, so long as the direction of light is correct to

109 within about 10 degrees, a convincing match can be obtained.

218 The effect of light and shade on wind turbines is an important aspect of their visual character and should be represented well. There may be a conflict between achieving realistic lighting and ensuring that the windfarm is clearly visible on the completed photomontage, and thus it will usually be a matter of professional judgement to achieve a satisfactory compromise based on an understanding of lighting conditions and experience of windfarm visibility.

Associated infrastructure and land use change

219 Windfarm proposals include elements other than wind turbines, typically including tracks, borrow pits, cabling and a substation. Additionally, a windfarm development may be both directly and indirectly responsible for vegetation and land use change. If these elements are likely to result in significant impacts, either individually and/ or collectively, they should be included in photomontages if possible, as shown in figure 29.

220 Some of these elements may be difficult to model well, particularly changes in vegetation. In these circumstances, it may be necessary to render them directly onto the photomontage, guided by a wireline or other computer generated image to ensure that the positioning, perspective and scale of these elements is correctly represented.

110 Figure 29: Representation of land use change (in addition to wind turbines) using photomontage

a: Photograph of existing conditions

b: Photomontage showing proposed land use change in association with windfarm

111 Other visualisation techniques

Wirelines superimposed on photographs

221 One difficulty of comparing separate wirelines and photographs, is that it is often difficult to interpret the exact spatial relationship between elements in the two images. One alternative is to present the wireline superimposed upon the photograph as shown in figure 30. This is almost a hybrid between a wireline and a photomontage. It has the advantage that the time consuming rendering stage of photomontage construction is avoided; however, in order to achieve a satisfactory superimposition of wireline on photograph, it is still necessary to achieve a quality of perspective match equal to that required for photomontage.

Coloured 3D rendering

222 Wireline diagrams are not suitable for depicting all the works that may be associated with a windfarm, both individually and collectively, for example forestry works, access tracks and borrow pits. One solution, short of a full photomontage, is to use a coloured computer rendering of the scene. This can represent the additional features required, whilst retaining much of the abstract simplicity of a wireline diagram. These techniques are not widely used and different rendering packages offer different facilities, so it is difficult to make firm recommendations on this practice at this stage.

Figure31: Coloured rendering showing proposed forestry works associated with a windfarm

112 Hand drawn illustrations

223 Drawings and paintings have been used for centuries to illustrate proposed landscape or architectural change. However, it is the production of these using computers that has resulted in radical changes to the way images are conventionally presented, with an associated demand for these to be based on technical data for which accuracy can be measured.

224 There are instances, however, when hand drawn illustrations remain an invaluable tool to the process of visual analysis and the illustration of impacts within an ES. This is mainly because they can offer the following:

• a clarity of image, by omitting some of the distracting details that might be prominent within a photograph but which are actually overlooked on site; • they can incorporate an element of interpretation by highlighting prominent focal features; and, finally, • their limitations are obvious – they are clearly not trying to replicate an exact view as it would be seen by the human eye.

225 However, for these same reasons, hand drawn illustrations also have disadvantages, chiefly that their quality is closely linked to the nature and abilities of the illustrator and they may be distrusted for incorporating 'artistic licence'. Hand drawn sketches are commonly included within ESs in two different formats as discussed below.

Diagrammatic sketches and annotated visualisations

226 Diagrammatic sketches allow the key visual elements of the visual composition to be drawn out and highlighted. This may be in relation to the landscape Figure32: Diagrammatic or the windfarm development, highlighting the main sketch of a visual characteristics and principles of design. The landscape

113 advantage of using this medium is that important points can be stressed without these being clouded by insignificant details. In addition, these diagrams are clearly not attempting to replicate an actual view.

227 It is useful to include within an ES visualisations that are annotated to show the position of key elements of the windfarm proposal, such as access tracks and borrow pits, in addition to the turbines. It is also useful to include turbine numbering on some of the visualisations so that individual machines can be easily identified and cross referenced.

Free-hand sketches

228 Free-hand sketches may be based on just observation, or made in combination with a computer generated image. They can highlight the key visual elements or components of a view, similar to other hand drawn illustrations but, even better, they can also convey some of the elements of landscape experience, such as Figure33: Free-hand exposure, landform shape and colour. These can be sketch of a used in combination with photographs within an ES, landscape but should not be used as a substitute for these.

Animation

229 Wind turbines are intrinsically dynamic objects, with large moving parts and variable orientation, so static images are in many ways an unsatisfying medium of illustration. Computer animation, videomontage and virtual reality techniques are being used to some extent to address this issue.

230 To date, most animation and videomontage has been used principally as a means of conveying a general impression of a development to the determining authority and the public, rather than as a tool for carrying out VIA or as part of an ES. However considerable scope exists for their use in the future as various techniques are developed and presented, and then tested against windfarms once these have been

114 built (similar to the scrutiny applied in the past to wirelines and photomontages). At present, the application of these techniques require specialist contractors.

231 Guidance on the various methods of animation is not within the scope of this study. However, it is hoped that supplementary information on this subject may be provided at a later date as the practice develops further.

115 Choice of visualisation

232 This section considers which, how, why and by whom photographs, wirelines and photomontages should be used.

233 To record the baseline conditions of a view, a photograph is required to be presented within the ES. In addition, a wireline diagram is required to indicate the position, scale and shape of proposed wind turbines. Photomontages can also be useful, to provide an impression of visual impacts and help people to interpret the judgements of the landscape architect or experienced specialist assessor, especially if they have less familiarity and/or experience of the particular landscape in question and how windfarms appear in different conditions. However photomontages can only illustrate how a windfarm would appear in a photograph of a development, not how it would appear in reality as discussed in paragraph 119.

234 The choice of viewpoints to be illustrated using photomontages in addition to wireline diagrams may be impossible to determine until after the initial stages of VIA, although many practitioners observe that it is predictably difficult to produce clear photographs, and thus photomontages, of windfarms from distances over 15km. It is recommended that the local planning authority and SNH are consulted regarding the final choice of visualisations for each viewpoint wherever possible.

Photo of existing view 235 In the past, there was often some dissatisfaction with

Wireline diagram the convention of presenting visualisations from separate viewpoints as a triple arrangement Photomontage comprising a photograph of the existing view and corresponding wireline diagram and photomontage as shown in figure 34 opposite. This was no fault of the Figure34: The triple arrangement visualisation arrangement per se, but because it is not of possible to present the triple visualisation at A3 paper visualisations

116 size while satisfying recommended image height and viewing distance criteria (paragraphs 126 and 129). This resulted in three key problems:

• the image was not clear because it was too small to represent the required amount of detail (discussed further in Appendix D); • the image was held at the correct viewing distance, but this was too close to be viewed comfortably; or • more commonly, the image was naturally held by the viewer at a comfortable distance, but this was not at the defined viewing distance so that the geometry of the image was incorrect and thus the image scale (and the elements seen within it) was viewed incorrectly.

Nevertheless, the triple format is a useful arrangement and should still be considered as one method for visualisation presentation when using sheets over A3 size, as described within Table 15 and shown in figures 38 and 40.

236 It is important to highlight that the production of different visualisations involves varying levels of data interpretation. Wirelines are based purely on objective data and thus, if only these are used to carry out visual analysis on site, there is a very clear, simple and direct relationship between the data and judgements made. In contrast, the production of photomontages incorporates a much more complex process of judgements in order to construct and render these, similar to any artistic illustration. In this way, although the scale siting and geometry of photomontages can be technically measured, the other qualities of the image will vary in relation to the skill and experience of the illustrator.

237 The difference between photomontages and wirelines in terms of the nature of information they convey and how this informs judgements, was considered by the University of Newcastle (2002). They state “wireframes [wirelines] tended to cause less under (or

117 over) estimation of visibility and visual effect, compared to photomontages….”.

238 Photomontages are discussed in more detail within the separate section on these within paragraphs 202-220. The proportion of viewpoints illustrated using photomontages within an ES will vary, depending on the specific characteristics of the proposed development and the landscape and visual resource; however ESs within Scotland commonly include photomontages for around one third of the viewpoints illustrated.

239 In certain circumstances, ‘regular’ photomontages (which are based upon a 50mm lens or equivalent) may be supplemented by a telephoto photomontage. This is where the photograph of the existing view is taken using a telephoto lens (as described in paragraph 155). Normally this would provide no benefit over a photo taken with a standard 50mm lens (or digital equivalent) and enlarged to a sufficient image size and comfortable viewing size, as shown by figure 21. However, in specific circumstances, the additional detail shown in a telephoto photograph can help compensate for the lack of shade differentiation able to be illustrated upon the printed page (refer to paragraph 134). These circumstances tend to occur where a windfarm would be seen in the very far distance against the sky. In these instances, the benefits may compensate for the disadvantage that this creates in terms of having to view an image at a very long viewing distance (figure 22c) and that this distance will vary from other visualisations produced for the same viewpoint.

240 It is important to stress that visualisations should never be used as a substitute to visiting a viewpoint. They remain only a tool for assessment - that is as an image that can be compared with an actual view of the landscape while other elements of the landscape experience can also be appreciated that are unable to

118 Figure 35: Use of a comfortable viewing distance

At a comfortable viewing distance (400 - 500mm) the viewer can alternate their view between the existing landscape and the visualisation, easing direct comparison and thus judgements on the proposed effect.

At a short viewing distance (300mm or less) the viewer can only either see the visualisation in front of them, or the existing view - not both. Thus direct comparison is less easy.

be incorporated within a two dimensional picture. To allow this use, it is recommended that visualisations should either be available to be taken out on site by the individual or, alternatively, are mounted upon boards out on site, as illustrated in figure 36. Because of a risk of vandalism or theft, the latter arrangement

may be possible during organised visits only. Figure 36: Visualisation mounted on a board on site in order to 241 Table 13 sets out the various applications of provide a direct comparison with present conditions. visualisations by different users, while figure 37 (Image courtesy Stuart Young indicates the process by which different visualisations Consulting) may be chosen.

119

Figure 37: Process of choosing visualisations for each individual viewpoint (subject also to consultation and agreement with the Planning Authority and SNH).

What is the purpose of the visualisation?

To inform the professional process of VIA only To illustrate predicted visual impacts to a wide audience

Are there likely to be significant visual impacts?

No Yes

Photomontage*

Is it possible to clearly illustrate Telephoto impacts within a photomontage photomontage (for example is the development may be provided close enough to the viewpoint)? in addition to ‘regular’ photomontage.

No Yes

What is the typical field of view that is able to show the key characteristics of the visual resource? Wireline and photograph of existing view 39 degrees or Over 39 degrees 29 degrees or over under (based on (based on using (based on using using eg 50mm eg 50mm lens or eg 70mm lens or equivalent) equivalent)

Single frame Panoramic photomontage* photomontage* 120 *plus photograph of existing view and wireline Table 13: Use of visualisations within VIA

User Process Visualisation* Use Basis of judgement Judgement

Landscape LVIA as part Wireline On site Professional Judgements of Architect or of EIA comparison knowledge and visual impact Experienced with visual experience of Visual magnitude and Specialist resource Impact Assessment significance of effect Assessor (VIA), windfarms, to be reported in ES and how wireline visualisations compare with built windfarms Photomontage On site Professional For general comparison knowledge and information only, with visual experience of VIA, not usually basis of resource windfarms, and how professional photomontage judgement visualisations compare with built windfarms Officer from Assessment Wireline On site Knowledge and Confirmation of Planning of ES comparison experience of the judgements made in Authority or with visual landscape, LVIA part of ES Consultee resource windfarms, and how wireline visualisations compare with built windfarms Photomontage On site Knowledge and Supplementary comparison experience of the information to help with visual landscape, illustrate the likely resource windfarms, and how visual impacts of the photomontage windfarm in its visualisations landscape setting in compare with built addition to windfarms associated developments and/ or land use change Determining Assessment Wireline On site Advice from Assess planning authority of ES comparison planning officers. officers’ report with visual Variable experience regarding resource or, of of the landscape and confirmation of lesser value, in windfarms. judgements made in comparison LVIA part of ES with photo of existing visual resource Photomontage On site Advice from Supplementary comparison planning officers. general information with visual Variable knowledge to help illustrate the resource or, of and experience of likely visual impacts lesser value, in the landscape and of the windfarm in comparison windfarms. its landscape setting with photo of in addition to existing visual associated resource developments and/ or land use change

121 Member of Understanding Wireline Access to ES Variable General indication the public of ES and only likely to background of the likely general visual occur in public knowledge on the visibility, scale and effect of building, thus landscape and form of the wind proposed comparison visual impacts of turbines. development with photo of windfarms. existing visual resource Photomontage Access to ES Variable Supplementary only likely in background information to help public knowledge on the illustrate the likely building, thus landscape and appearance of the in comparison visual impacts of windfarm. with photo of windfarms. existing visual resource. * Telephoto photomontages may also be produced and used in specific circumstances as supplementary information as described in paragraph 239.

122 Presentation of visualisations

Presentation for different audiences and uses

242 There are numerous different ways to present visualisations within windfarm ESs. The most appropriate format will depend on a number of factors as follows:

• How and by whom the information will be used; • Where the information will be used; • What is required to be illustrated by the visualisation; and • How the information will be distributed.

243 The landscape architect or experienced specialist assessor will use visualisations as a tool for VIA, both interpreting the images and basing their assessment on a high level of experience and knowledge of VIA and windfarms, as well as a clear understanding of how visualisations differ from views seen with the naked eye. Planners will use visualisations similarly, although they tend to use photomontages (rather than wirelines) more than the assessor. They may also study the visualisations to verify the landscape architect or experienced specialist assessors’ findings. The general public will more commonly use photomontages as an illustration of the predicted image of a windfarm and expect minimal interpretation to be required.

244 If the visualisations are to be used in the field, there is generally less need to explain and stress the differences between these images and real life views, although the importance of minimising page size and page ‘fold-outs’ will be greater. If the visualisations are to be viewed only in an office, home or other building, it will be more important to emphasise how the visualisations should be used and their limitations in relation to real life views, whilst the size of images may be more flexible. For public meetings or displays, visualisations will usually need to be larger; but the

123 limitations of viewing remote from the real view also apply.

245 The specification of the visualisation will affect how it can be presented, particularly what size of paper is required to illustrate the required horizontal field of view, viewing distance and desired image height. Figures on the size of paper required to accommodate these variables are included in Table 14. There is no perfect solution, as the choice of paper size inevitably involves trade-offs between clarity, ease and cost of reproduction, and practicality of use. All formats have advantages and disadvantages, some of which are described in Table 15.

246 The developer is required to send paper copies of the ES to the determining authority and consultees. However they may charge for some or all parts of the ES if requested by other parties or individuals. As a consequence, for the sake of maximising accessibility, it is in everyone’s interests to minimise the potential costs of reproduction. To enable greater numbers of people to study visualisations on site, it may be possible to produce a select number of these within the ES Non Technical Summary (NTS) or as a separate appendix (either free or for a small cost). The disadvantage of producing an extract of this sort, however, is that the visualisations may be misused or misunderstood due to the lack of accompanying information that is found within the main ES.

247 Options may exist for purchasing an ES digitally on CD or for the report to be available via the developer’s website, which would incur minimal financial cost. However some domestic or office PCs may struggle to handle the volume of data involved in the photographic images used. In addition, as many of the visualisations represent a wide field of view that would ordinarily be printed at a size larger than most computer screens, the viewer will either need to view these images at a shorter distance than specified or,

124 alternatively, zoom in on only one part of the image at a time – both of which are unsatisfactory practices.

248 The size of paper required to illustrate visualisations will depend on 4 key factors: the field of view represented by the photograph (paragraph 127); the viewing distance of the paper (see paragraphs 125- 126 and 255-256 and Appendix A); the required image size to be clear (showing sufficient detail) (paragraph 129); and how many images are required to fit on each sheet. As mentioned in paragraph 129, an image height over 130mm is acceptable, while an image height of approximately 200mm high is recommended. The following table shows some examples of how these factors influence paper size.

Table 14: Size of paper required to accommodate specific field of view, image size and viewing distance (using 50mm camera lens).

Viewing distance of 500mm, with Viewing distance of 400mm, with image height of 200mm image height of 200mm

Width of Width of Field of Standard Field of Standard paper paper view paper view paper required required (deg) size (deg) size (mm) (mm)

30 262 A4 30 209 A4 40 349 A3 40 279 A3 50 436 A2 50 349 A3 60 524 A2 60 419 A2 70 611 A1 70 489 A2 80 698 A1 80 559 A2 90 785 A1 90 628 A1 100 873 A0 100 698 A1 110 960 A0 110 768 A1 120 1047 A0 120 838 A0 130 1134 A0 130 908 A0 140 1222 > A0 140 977 A0 150 1309 > A0 150 1047 A0 160 1396 > A0 160 1117 A0 170 1484 > A0 170 1187 > A0

180 1571 > A0 180 1257 > A0

125 Combinations of visualisations

249 When presenting visualisations in an ES or at an exhibition, it is usual to present combinations of visualisations together, most commonly photograph and wireline, or photograph, wireline and photomontage. This allows the user of the ES to refer to a photograph of the existing conditions and then make a direct comparison between this and the wireline and photomontage.

250 In the past, it has been common practice to present all three of these images together, one above the other on a single A3 sheet. However, as discussed previously in paragraph 235, this layout is only possible if the fields of view shown, the viewing distances, or both, are severely limited beyond recommended standards.

251 A number of alternative options exist for producing combinations of visualisations within an ES. Some of these are described below, illustrated diagrammatically within figure 38, and shown as examples of presentations in figures 39-44. However it is important to stress that these options represent just a few of the many possible scenarios available and each of these has advantages and disadvantages. There is no perfect solution, as implied within Table 15. Rather, the relative pros and cons of all options need to be weighed up for each VIA while considering the following guidance.

• For every viewpoint A photo of the existing view and corresponding wireline diagram is required. The viewing distance should be over 300mm, with a recommendation of between 400-500mm. The field of view of the photograph should be determined by the landscape architect or experienced specialist assessor based on the key characteristics of the visual resource and the extent of view required to illustrate this in relation to the windfarm (see paragraphs 135-138).

126 If the recommended image height of 200mm is used (University of Newcastle, 2002) for the photograph of the existing view (taken with a 50mm focal length lens or equivalent and printed with the minimum acceptable viewing distance of 300mm), this combination can only be accommodated upon an A3 height sheet if the wireline is severely cropped both top and bottom (figure 39). This may be acceptable, where there is only little variation of landform represented within the lower and upper parts of the image, and thus little wireline information is required to be able to directly compare this to the photograph. However, for viewpoints where this is not the case, either the height of the image size needs to be less, the page larger, or the photograph and wireline need to be shown on separate pages. Neither of these options is ideal, as detailed in table 15. Consequently, a decision needs to be made that is based on balancing the relative advantages and disadvantages for each viewpoint.

• For viewpoints where there is likely to be significant visual impacts and where illustration is possible using photomontage A photomontage, if required, may either be presented together with the photograph and wireline, as a triple arrangement, as discussed in paragraph 235 and shown in figure 40, or upon a separate page from the photograph and/or wireline. The advantages of the former is that direct comparison between all the visualisations are possible; the advantages of the latter is that presentation on a separate page emphasises the different quality of information that the photomontage presents while maximising its legibility. Whichever format used, the image height, horizontal field of view and viewing distance should match the photograph of the existing view and meet the minimum standards stated.

127 • For viewpoints where there is likely to be significant visual impacts, but where it is not possible to adequately illustrate the windfarm due to its far distance and because it is seen against the sky. In these circumstances, the viewpoint should usually be illustrated using a photograph of the baseline conditions in addition to a wireline diagram. However, in exceptional circumstances, as discussed in paragraph 239, for example a designated site of international importance, a photomontage based on a photograph taken with a telephoto lens may be useful. However it is important to highlight that this photomontage should only be produced in addition to the ‘regular’ photomontage (based on a 50mm lens) and upon a separate sheet. It should never be produced in isolation as it will not show the full context of the view in relation to the windfarm and key characteristics of the visual resource. Additionally, the use of these photomontages should only be provided with caution, as they will usually require a very long viewing distance that means that the montage needs to be wall mounted or held by another person, and this viewing distance will obviously differ from the other photomontages within the ES, which is not recommended.

• For viewpoints where there are very wide or panoramic views As previously discussed, the width of view of the photograph, and thus the standard photomontage, should be based on a judgement of what is necessary to illustrate the key characteristics of the visual resource comprising the ‘essential’ setting to the proposed development (paragraph 127). However, in certain circumstances, for example where a viewpoint enjoys a panoramic view up to 360°, such as from a mountain top, it may be useful to also include an additional ‘context’ photograph of the wider panorama. Not because this is required to illustrate the essential setting of

128 the proposed windfarm, but just for background information. This context photograph should be presented together with the standard photograph, with an outline showing which part of it corresponds to the extent of the standard photograph. Given that the context photograph is for background information only, it does not need to meet recommendations for image size or viewing distance (this should be noted on the visualisation).

129 Table 15: Comparison of advantages and disadvantages for different visualisation combinations Option Paper horizontal Approximate No of sheets Advantages Disadvantages no size field of height of image required to view (mm) show fig no based on photograph, 50mm wireline and lens/ photomontage viewing distance 1 A1 117° Photo = 200 1 Triple arrangement Large paper size is Wireline = 140 allows direct unwieldy. VD = Photomontage comparison Requires vertical 400mm = 200 between existing and horizontal photograph, fold-out within A4/ wireline and A3 ES document. photomontage. Clarity of recommended image size and viewing distance. Large paper size may be simpler to present at exhibition. 1a A2 82° Photo = 140 1 Triple arrangement Large paper size is Wireline = 100 allows direct unwieldy. 40 VD = Photomontage comparison Requires vertical 400mm = 140 between existing and horizontal photograph, fold-out within A4/ wireline and A3 ES document. photomontage. Image height Large paper size shorter than may be simpler to recommended size present at for best exhibition. representation.

2 A3 57° Photo = 200 3 Clarity of Can only Wireline recommended accommodate 42a, b, VD = 200 image size and narrow horizontal c =400mm viewing distance. field of view that will only be acceptable from a limited number of viewpoints. Comparison of existing photograph and wireline more difficult on separate sheets 3 A3 76° Photo=150 2 Size of sheet easy to Image height Wireline accommodate shorter than 41a, b VD =100 within ES report. recommended size =300mm for best representation. Viewing distance shorter than recommended. Need to crop wireline.

130 Option Paper horizontal Approximate No of sheets Advantages Disadvantages no size field of height of image required to view (mm) show fig no based on photograph, 50mm wireline and lens/ photomontage viewing distance

4 A3 110° Photo = 150 2 Allows wider Image height height Wireline = 100 horizontal field of acceptable, but 43a, b A2 VD view than on A3. shorter than width =300mm recommended size for best representation. Viewing distance shorter than recommended. Fold-outs are more difficult to manage within ES document.

5 A3 94° Photo = 200 3/4 Image height meets Comparison of height Wireline = 200 recommendations existing 44a, b A2 VD and allows wider photograph and width =500mm horizontal field of wireline more view. If difficult on supplementary separate sheets. telephoto Fold-outs are photomontage more difficult to shown, may manage within ES improve visibility of document. very distant If supplementary windfarm seen telephoto against the sky photomontage included, this will need to be viewed at viewing distance that varies from other visualisations and is usually longer than can be hand held.

6 A3 57° Photo = 200 3 Image height meets Supplementary height Wireline = 200 recommendations. ‘context’ A3 and VD Context photo Limited horizontal panorama A2 =400mm = 70mm field of view. photograph will width Supplementary be limited in panorama height if included photograph can upon same page show wider context as standard of site. photomontage. If A3 width, narrow horizontal field of view.

131 Option Paper horizontal Approximate No of sheets Advantages Disadvantages no size field of height of image required to view (mm) show fig no based on photograph, 50mm wireline and lens/ photomontage viewing distance

7 A2 57° Photo = 200 2 Photo and wireline A2 size page portrait Wireline = 200 can be shown on a difficult to include VD single page and within ES and use =400mm thus directly on site. Either as compared easily. loose map within bound wallet, or bound sheet that has to be folded up and out. Photomontage sheet either on different sized paper or inefficiently occupying small proportion of A2 sheet.

132 252 To allow easy comparison between visualisations on separate pages, it is recommended that these are included within a loose leaf format so they can be taken out and observed side-by-side as necessary. This arrangement also facilitates the temporary removal of certain graphics for use in the field. However, with this flexibility comes the risk that parts of the ES, and particularly the visualisations, may be extracted, and either not returned or, alternatively, inserted back incorrectly. This is a difficult issue to resolve although, as discussed in paragraph 246, it may be ameliorated if some key visualisations for each scheme are available (either free or at a small cost) within a separate document or within the ES Non Technical Summary. Figure 45 – Binding of oversize sheets within report’ 253 Where visualisations are not required to represent a

very narrow horizontal field of view, a sheet wider than Recommended – sheet with fold A3 will be required. These can either be bound within outs the document with fold-outs to the side, or alternatively, included as loose folded sheets within a bound wallet. Double-sized A3 sheets or an extended A3 sheet (A3 height +A2 or A1 width) are sometimes binding bound into a document so that the image extends over

both facing pages; however these face the problem of the binder obstructing or distracting attention to/from part of the image, even if using a minimal sized velo Not recommended – two sheets binder, and are thus not recommended. Nevertheless, bound in middle if binding is carried out in this way, it is advised that the visualisation is positioned so that the proposed development does not lie within the spine area.

254 Usually, it will be appropriate to present the photograph, wireline and photomontage such that the proposed wind turbines are centralised in the horizontal field of view. However, at certain viewpoints, it may be appropriate to centre the view on an alternative feature, or part way between two or more foci. These additional foci may or may not be windfarms. In these circumstances, it is important that the proposed windfarm does not appear at the far

133 edge of the image. This is because sufficient context/ horizontal field of view needs to be provided for each of the foci.

255 As previously highlighted, it is important that visualisations are viewed at the correct ‘viewing distance’ – that is the distance between the eye and the image that directly relates to the visualisation calculations and image size. This is discussed further within paragraphs 125-126 and 255-256 and Appendices A and C. This distance should always be stated next to a visualisation. In addition, the visualisation should be large enough to show sufficient field of view and detail as described further in paragraphs 129 and 248.

256 To accommodate the horizontal and vertical field of view required at the recommended viewing distance, there will usually be a requirement to use pages larger than A3, either as pull-outs or folded within a wallet. It is important that the viewing distance should be the same for all visualisations in an ES (unless there is a very good reason for doing otherwise, which should be stated and clearly justified). This avoids the need to search out the specification for viewing distance on every image and to repeatedly adjust the position of the document. Experience has shown that, where different viewing distances are used, rather than the viewer altering the distance at which they view each visualisation, there is a tendency to either just adopt the first viewing distance marked and assume this to be standard or, alternatively, adopt a single ‘average’ viewing distance for convenience. Either action is unsatisfactory as it results in some of the visualisations being viewed incorrectly.

Information to provide

257 Information provided on the specification of a visualisation should be sufficient for the reader of either an ES or a display board to understand the basis of the visualisation, but not so much as to be

134 overwhelming. Some of this information should be shown upon the visualisation sheet itself, while the remainder can be put within the VIA or appendices. The information provided should include that within the following Table 16.

Table 16: Information to accompany visualisations 1 Overall ‘health warning’ summarising how the photomontage should be used and its limitations, and referring to further detail on this issue elsewhere in the ES 2 Information on viewpoint location, altitude and horizontal field of view, as listed within Table 8. 3 Direction of centre of photograph as a bearing 4 Correct viewing distance

5 Whether the image is panoramic or planar perspective and/ or cylindrically projected. 6 Distance to nearest visible turbine in kilometres

7 Cross reference to assessment of viewpoint within VIA and relevant technical appendices. Cross reference to information on photography, listed within Table 12, within VIA and/ or relevant technical appendices.

8 Position of view horizon where there has been unequal cropping between the top and bottom of the image ( for example because the key view from a mountain top is downwards)

258 Additional information on the production of the visualisations is important (for example the camera specification and date and time of photograph). However this is not required to interpret the visualisation, and thus can be provided elsewhere within the VIA text or in a clearly referenced appendix.

Paper and printing

259 There is an extremely wide variety of different printers and paper types available with which to print visualisations. To obtain the best results in relation to the size and type of visualisation, it is recommended that advice is sought from specialist providers.

135 However a number of very general guidelines can be provided within this Good Practice Guidance.

260 If using an inkjet printer, in order to produce a higher contrast finish (where ink sits on the surface rather than soaking in), a high gloss paper is recommended as shown within figure 46a. Very glossy paper, similar in appearance to photographic paper will tend to provide the best image resolution. However this is very expensive and tends to be heavy and thick; so, while it is useful for exhibitions, it can add undesirable weight and bulk to an ES document. As a compromise, coated paper is an acceptable alternative (figure 46b), having lower absorption rates than standard copy paper (figure 46c), while possessing some of the shine and impenetrable surface of high gloss paper, and while being less expensive and heavy.

261 If using a colour laser printer, a smooth white copier paper is usually recommended. This should be of at least 90gm weight.

262 The quality of a printed visualisation will depend significantly on the printing process and set-up. Colour inkjet printers tend to show more detail than other machines because of their higher colour range and resolution. However, it is generally difficult to produce large numbers of pages in this way; so, for mass printing, either colour laser printing or professional printing may be advisable.

263 Printing multiple copies of sheets larger than A3 can be expensive and, if folding is required, may result in a bulky ES report. However, these difficulties must usually be accepted if recommendations for viewing distance, field of view and presentation are to be met; indeed, they are already commonplace for most windfarm ES submissions in Scotland.

136 Exhibition display

264 Exhibitions provide an opportunity to present larger visualisations. There is a definite advantage in printing at large sizes to include as much detail as possible, particularly photographs and photomontages. The viewing distances should always be stated, as for ES visualisations and as noted within Table 16. These may be larger than the 500mm maximum appropriate for hand-held material. The use of a footplate or cordon in front of exhibition boards can direct viewers to the correct viewing distance.

265 Cylindrical panoramas should either be presented on a curved surface, or presented in a way that allows sideways movement from one side of the image to the other at a constant viewing distance (see Appendix B).

137 Table 17: GOOD PRACTICE GUIDANCE SUMMARY

VISUALISATION

Paragraph Minimum requirements Preferred requirements in report General 119 The limitations of visualisations should Assessment of visualisations 134 be understood before making any should be carried out on site assessment based upon them. where direct comparison can be Assessment of visualisations off site made to the real life view. should include consideration of the description of viewpoint characteristics within the ES that cannot be represented by a 2-dimensional image.

Key issues 124 The size of visualisation should be affecting determined by the most appropriate visualisations vertical and horizontal field of view and the recommended viewing distance (while being large enough to show sufficient detail).

126 A viewing distance of 300mm – A viewing distance of 400 – 500mm. 500mm.

127 The horizontal and vertical field of view 143 for each visualisation should be determined by the landscape architect or experienced specialist assessor.

129 An image height of over 130mm for An image height of approximately 142 hand-held material. 200mm for hand-held material.

130 Viewpoint visualisations should be assessed together with other aspects of VIA, including visibility as shown by ZTVs.

Photography 146 SLR camera for 35mm film or digital SLR

135-138 Field of view, vertically and horizontally, A panorama should be taken to should be determined by the landscape extend the entire width of open architect or experienced specialist view (excluding towards the sun if assessor, in addition to the central point this is at a low angle) of the photo.

147 Levelled photographs, using tripod and Panoramic tripod head spirit level

149 Fine-grained 35mm film (ISO 200 or Film ISO 100 or less less)

138 Paragraph Minimum requirements Preferred requirements in report Photography 152-153 50mm fixed focal length lens for 35mm Telephoto lens in very specific (continued) 157-158 film. Lens giving similar field of view for circumstances in addition to digital. 50mm. Do not use zoom lens. Take vertical (portrait) format panorama where a tall vertical field of view is to be represented.

159-161 Ensure good contrast within Take photographs in strong side Table 11 photograph. Direction and intensity of light conditions to emphasise 164 light should be sufficient to capture topography. existing/ proposed wind turbines on photographs. Not directly into sun. Reveal site and surrounding key characteristics of landscape and visual resource.

165-167 Record information on specification and conditions of photographs as listed in Table 12.

163 For panorama, manually set exposure setting to ensure good lighting over the entire panorama, but particularly the site and key characteristics of the area. Post 168-169 Scan negatives to a minimum of Use a bureau service offering photographic 2400ppi, taking care to achieve clean Photo CD scans processing image

174-175 Splice frames manually to build up Use software to re-map frames to panorama for photomontages cylindrical perspective and correct for lens defects

173 Use automatic splicing software only for photos to be used as background information and never for photomontages

175 Provide overlap of frames by between ¼ and ½ frame width.

176 Illustration of turbines should be based It is recommended that Illustration upon correct hub height, rotor diameter of turbines should be based on and general shape detailed ‘engineering’ drawing.

177-179 Wind turbines should be shown all Wind turbines shown facing the facing a specific compass bearing, not direction of the prevailing wind all towards the viewpoint.

139 Paragraph Minimum requirements Preferred requirements in report Post 180-184 Image enhancement, such as photographic sharpening and colour balance should processing be avoided if possible. However, if (continued) required to improve clarity, this should only be carried by experienced practitioner and with care. Only methods that could be done in a conventional darkroom should be adopted. These should be applied over the whole image, rather than selectively to emphasise only some features that will change the image content.

Wirelines 189-191 Use OS Panorama DTM as basis for Use OS Profile DTM as basis for wirelines wirelines

190 Ensure sufficient data is included to extend to the distant horizon (which may be outwith the study area)

194 Include earth curvature correction in wirelines

192-193 True panoramas or planar perspectives Ensure that wirelines are true with a panel width of less than 20° panoramas

176 Ensure that all proposed turbines are Include associated elements such 197-200 revealed in wirelines as proposed tracks, buildings and overhead electricity lines.

197 Use contrasting colour and/or shade for Use DTM landform lines, possibly 196 turbines and DTM mesh with lighter coloured broad DTM mesh too, to avoid colour/shading mass seen at far distances. 188 Wirelines with labelled turbine numbers 200 should be included within the ES.

Photomontage 205 Produce photomontages where significant impacts can clearly be illustrated

206 Do not excessively exaggerate the visibility of the windfarm, limiting rendering to that which looks realistic and could be done in a conventional darkroom.

140 Paragraph Minimum requirements Preferred requirements in report Photomontage 210 Use a wireline to ensure accurate (continued) perspective match with photographs

212 Provide 12 figure grid reference to Provide compass bearings to ensure good match of photo and prominent features in the view. photomontage.

217 Ensure that lighting of montage matches lighting of photograph. This should be based upon date and time photo was taken.

176 Illustrate all wind turbines within Show variable rotor position within 219 photomontage. photomontage. Include additional elements in photomontage, such as forestry works, roads and borrow pits

Other 221-231 Consider use of techniques other than visualisation simple photos, wirelines and techniques photomontages where appropriate.

Choice of 233 Wirelines are required for each Provide photomontages where visualisation type viewpoint in addition to a matching impacts are likely to be significant photograph of the existing view. and a windfarm could be clearly seen within a photograph

236-237 Wirelines should be used where visualisations require to be based on objective data only

Presentation 246-247 Provide paper copies of all visualisations Provide digital copies of visibility within the ES maps and visualisations in addition to paper copies, or provide extracts that can be obtained/ purchased separately (free of charge or at minimal cost).

129 Images should be at least 130mm high. Images approx 200mm high are recommended.

If more than one image is shown upon a page, this should be separated by an area or strip of blank space to maximise legibility.

249 A photograph of the existing view Wirelines should ideally be 250 should be followed directly by the presented next to the 251 wireline. The wireline should then be corresponding photograph upon followed by the corresponding a single page whilst also meeting photomontage(s) if being produced. the recommended image height and viewing distance.

141 Paragraph Minimum requirements Preferred requirements in report Presentation 249 A photograph of the existing view Wirelines should ideally be (continued) 250 should be followed directly by the presented next to the 251 wireline. The wireline should then be corresponding photograph upon followed by the corresponding a single page whilst also meeting photomontage(s) if being produced. the recommended image height and viewing distance.

124 The page size should be determined by 255 the most appropriate field of view 256 together with the required viewing distance.

252 Allow visualisations to be obtained Include visualisations within ES in separate from the main ES for direct loose leaf format so that comparison side-by-side and to be visualisations can be extracted viewed in the field. and compared side-by-side.

125-126, Always note correct viewing distance on A viewing distance of 400- 255-256 a visualisation. Use a viewing distance 500mm is strongly recommended. of 300-500mm for material intended to be hand held. The viewing distance should be the same for each visualisation within an ES.

257 Include all information in Table 16, including location, direction of view, viewing distance and distance to nearest visible turbine on page

241 Consider carefully the different options Consult with the Planning 251 for presenting visualisations for different Authority and SNH regarding Table 13 viewpoints. options

260 Use coated paper for printing. Use high gloss paper for specific presentations where weight and mass are not a limiting factor.

240 Use large display boards for exhibitions. Consider use of curved display 264-265 The correct viewing distance should be boards for visualisations at very obviously marked upon the exhibitions. ground. Consider mounting some visualisations on display boards on site at the viewpoint locations for direct comparison with the ‘real life’ view.

142 5 Conclusions

266 Visual analysis of windfarms is just one part of the wider study of Visual Impact Assessment. In turn, VIA forms just one part of the wider Landscape and Visual Impact Assessment within an Environmental Impact Assessment. Yet within the visual analysis process itself, there is a wide range of different tools and techniques that can be used.

267 While this Good Practice Guidance can advise on the different purposes, uses and limitations of these processes and set down some minimum technical requirements, it cannot prescribe a single recommended method as there is no ‘one size fits all’ solution.

268 When selecting the most appropriate type of ZTV mapping and visualisations, it is important to remember why they are being produced, how they can be used and what they can offer. Essentially ZTVs and visualisations are only tools. Behind all their planning, specification and production is the desire for them to aid the assessment of significant visual effects; however they can never reflect the whole story nor, indeed, provide the whole answer.

269 ZTVs and visualisations will be read in different ways by different people, based on their experience and understanding of visual impacts, windfarms, and how these are typically represented by visualisations. As a consequence, there is no single format nor method of production that will satisfy every person’s requirements. The Environmental Statement should instead focus on including information used by the landscape architect or experienced specialist assessor in carrying out the VIA, and providing sufficient information to aid other people’s understanding of the likely impacts of a windfarm in the landscape and how the judgements within the VIA were made.

143 270 It is imperative that the selection and use of ZTVs and visualisations as part of a VIA process is carried out in an informed, methodical manner and for this process and its findings to be documented in a transparent way. The integrity and credibility of VIA and EIA depends on a detailed and explicit declaration of the basis upon which all aspects of the assessment have been made. For VIA, this includes the technical specification of visibility maps and visualisations.

271 General guidance on assessing significance of impacts is contained within the Guidelines for Landscape and Visual Impact Assessment (Landscape Institute & Institute of Environmental Management & Assessment, 2002).

272 This Good Practice Guidance provides a starting point for understanding the various methods of visual representation of windfarms, while appreciating that these methods will continue to change and evolve, as people find new and better methods and tools. Thus this report reflects a current understanding of some of the key issues relevant to the visual representation of windfarms, but it is envisaged that this will require future updating.

273 A particular issue that calls for further guidance in terms of visual analysis is the cumulative landscape and visual impacts of windfarms. Whilst the basic principles of VIA for multiple developments are similar to those for individual developments, accumulation makes prediction and assessment during VIA even more complex, and presents new challenges in terms of illustration and presentation. Additional information usually required for cumulative VIA (CVIA) includes cumulative ZTVs and cumulative visualisations.

274 Offshore wind energy development also requires separate guidance in relation to visual representations. While the basic principles of VIA, and the tools used to carry out this process, are the same as for onshore

144 developments, there are some distinct differences, particularly in relation to visibility over the sea, the horizontal emphasis of views, turbine lighting, and the provision of distinct visual references.

275 Animation and video montage are other methods of visualisation, outwith the scope of this study, for which guidance would be beneficial.

145

146 Appendix i

Bibliography

ETSU. 2000. Cumulative Effects of Wind Turbines, A Guide to Assessing Effects of Wind Energy Developments. ETSU W/14/00538/Rep

Gregory, R. L. 1990. Eye and brain. 4th edition. Weidenfeld and Nicolson, London.

Hawkins, K. & Marsh, P. 2001. The Camera Never Lies… Paper presented to the BWEA 23 Conference, Brighton, October 2001.

Landscape Institute & Institute of Environmental Management & Assessment (LI-IEMA). 2002. Guidelines for Landscape and Visual Impact Assessment. 2nd edition. Spon Press, London.

Pirenne, M. H. 1967. Vision and the eye. 2nd edition. Chapman and Hall, London.

Pirenne, M. H. 1970. Optics, painting and photography. Cambridge University Press, Cambridge.

Ray, S. F. 2002. Applied photographic optics. Third Edition. Focal Press, Oxford.

Richters, J. P. and Richters, I, A. 1939. The literary works of Leonardo De Vinci. Oxford University Press, London.

Scottish Executive Development Department. 1999. Planning Advice Note 58. Environmental Impact Assessment.

Scottish Executive. 2000. National Planning Policy Guidance 6. Renewable Energy Technologies.

Scottish Executive. 2002. Planning Advice Note 45. Renewable Energy Technologies

147 Scottish Natural Heritage. 2001. Guidelines on the Environmental Impacts of Windfarms and Small Scale Hydroelectric Schemes. SNH: Redgorton, Perth.

Scottish Natural Heritage. 2003. SNH Policy on Wildness in Scotland’s Countryside. SNH Policy Statement No 02/03.

Scottish Natural Heritage. 2005. Cumulative Effect of Windfarms. Version 2 revised 13.04.05. Guidance. Available at www.snh.gov.uk.

Scottish Natural Heritage. 2005. Environmental Assessment Handbook, 4th edition. Available at www.snh.gov.uk.

Taylor, B. 1719 (reprinted in facsimile Andersan, K. 1992. Brook Taylor’s work on linear perspective. Spriner-Verlag, New York).

Turnbull Jeffrey Partnership. 1995. Photography and Presentation of Photographs for Environmental Assessment Work: Background Information. Unpublished.

Walters, N.V & Bromham, J. 1970. Principles of perspective. Architectural Press, London.

148 List of Environmental Statements assessed

These ESs were chosen by the Steering Group to represent a wide range of visualisation methodologies and quality and should not be taken as representing either best or worst practice.

Airtricity. 2002. Ardrossan Windfarm Environmental Statement.

Airtricity. 2002. Ardrossan Windfarm Non Technical Summary.

Airtricity. 2002. Ardrossan Windfarm Planning Statement.

Airtricity. 2002. Proposed windfarm at Ardrossan. Supplementary paper on Knock Jargon Fort assessment of landscape setting. Prepared for Airtricity by Land Use Consultants.

Airtricity. 2003. Dalswinton Windfarm Environmental Statement.

Community Windpower Ltd. 2003. Proposed Wardlaw Wood Wind Farm, Dalry. Supplementary Landscape and Visual Impact Assessment.

FARRWAG. 2003. Farr Windfarm further comments and revised alternative layout.

National Wind Power. 2002. Farr Wind Farm. Environmental Statement Volume 4. Technical Appendices.

National Wind Power. 2002. Farr Wind Farm. Environmental Statement Volume 3. Volume of Figures.

Natural Power. 2001. Planning Application for the proposed wind farm extension at Windy Standard, Dumfries & Galloway. Environmental Statement. Volume 1 of 2.

149 Natural Power. 2001. Planning Application for the proposed wind farm extension at Windy Standard, Dumfries & Galloway. Environmental Statement. Volume 2 of 2.

Natural Power. 2003. Planning application for the proposed wind farm at Mid Hill, Aberdeenshire. Environmental Statement.

Scottish and Southern Energy. 2003. Gordonbush Windfarm Environmental Statement. Prepared for SSE Generation Ltd by Land Use Consultants.

Scottish Power. Undated. Whitelee Windfarm Environmental Statement.

Scottish Power. Undated. Whitelee Windfarm Environmental Statement. Figures.

Scottish Power. Undated. Whitelee Windfarm Environmental Statement. Technical Appendices.

150 Appendix ii

Glossary

Definitions are provided below for terms as used in this document (these may differ within other publications).

Reference should be made to the glossary contained within the Guidelines for Landscape and Visual Impact Assessment (2002). Some of the terms are repeated here however (marked by an asterisk), due to their particular relevance to the visual representation of windfarms.

Assessment (landscape). An umbrella term for description, classification and analysis of landscape.*

Cumulative effects. The summation of effects that result from changes caused by a development in conjunction with other past, present or reasonably foreseeable actions.*

Element. A component part of the landscape or visual composition.

Environmental Impact Assessment. The evaluation of significant effects on the environment of particular development proposals.

Horizontal array angle. This term is used to describe the horizontal field of view occupied by the visible part of a windfarm.

Landscape. Human perception of the land conditioned by knowledge and identity with a place.*

Landscape character. The distinct and recognisable pattern of elements that occurs consistently in a particular type of landscape, and how this is perceived by people. It reflects particular combinations of geology, landform, soils, vegetation, land use and human settlement. It creates the particular sense of place of different areas of the landscape.*

151 Landscape effect. This derives from changes in the physical landscape, which may give rise to changes in its character and how this is experienced. *

Landscape feature. A prominent eye-catching element, for example, wooded hilltop or church spire.*

Landscape resource. The combination of elements that contribute to landscape context, character and value.*

Magnitude. A combination of the scale, extent and duration of any impact.*

Mitigation. Measures, including any process, activity or design to avoid, reduce, remedy or compensate for adverse landscape and visual impacts of a development project.*

Panorama. An image, covering a horizontal field of view wider than a single frame. Panoramic photographs may be produced using a special panoramic camera or put together from several photographic frames. Wirelines and photomontages may also be panoramas. See Appendix B.

Photomontage. A visualisation based on the superimposition of an image onto a photograph for the purpose of creating a realistic representation of proposed or potential changes to a view. These are now mainly generated using computer software.

Receptor. This term is used in landscape and visual impact assessments to mean an element or assemblage of elements that will be directly or indirectly affected by the proposed development*.

Sensitivity (landscape or visual). The extent to which a landscape or visual composition can accommodate of a particular type and scale without adverse effects on its character or value.

152 Scoping. The process of identifying the likely significant effects of a development on the environment which are then to be the subject of assessment.

Telephoto Photomontage. A type of photomontage (see above) based on a photograph taken using a telephoto lens (over 50mm).

35mm camera. This is a Single Lens Reflex (SLR) camera that uses a 35mm film gauge with a negative size of 36 x 24mm.

Visual Amenity. The value of a particular area or view in terms of what is seen.*

Visual effect. This results from changes in the composition of available views as a result of changes to the landscape, to people’s responses to the changes, and to the overall effects with respect to visual amenity. *

Visualisation. Computer simulation, photomontage or other technique to illustrate the appearance of a development. *

Windfarm. Also known as a ‘wind farm’. A development of wind turbines for the purposes of generating energy.

Wirelines. Also know as ‘wireframes’ or ‘computer generated line drawings’. These are computer generated line drawings, based on digital terrain models (DTM), that illustrate the three-dimensional shape of the landscape in combination with additional elements.

Zone of Theoretical Visibility (ZTV). Also known as a Zone of Visual Influence (ZVI), Visual Envelope Map (VEM) and Viewshed. This represents the area over which a development can theoretically be seen, based * As defined by the Landscape on digital terrain data. This information is usually Institute and Institute of presented on a map base. Environmental Management and Assessment (2002)

153 Zone of Visual Influence (ZVI). See Zone of Theoretical Visibility (ZTV) above.

154 Appendix iii

Acronyms and abbreviations

APS Advanced Photographic System

CAD Computer Aided Design

CD Compact disc

CIA Cumulative Impact Assessment

CLVIA Cumulative Landscape and Visual Impact Assessment

cm Centimetre

DSM Digital Surface Model

DTM Digital Terrain Model

DPI Dots per inch

EIA Environmental Impact Assessment

ES Environmental Statement

EXIF Exchangeable image file

GIS Geographical Information System

GPS Global Positioning System

GLVIA Guidelines for Landscape and Visual Impact Assessment

ISO International Standards Organisation (set film speed ratings)

LIA Landscape Impact Assessment

LVIA Landscape and Visual Impact Assessment

m Metre

mm Millimetre

NGR National Grid Reference

NTS Non Technical Summary

OS Ordnance Survey

PC Personal Computer

PPI Pixels per inch

155 RMS Root mean square

SLR Single lens reflex

SNH Scottish Natural Heritage

SRF Scottish Renewables Forum

SSDP Scottish Society of Directors of Planning

TIN Triangulated Irregular Network

VEM Visual Envelope Map

VIA Visual Impact Assessment

ZTV Zone of Theoretical Visibility

ZVI Zone of Visual Influence

2D Two dimensional 3D Three dimensional

156 Technical Appendices

A Camera Perspective Linear Perspective The pinhole camera Practical cameras Wide angle geometry Image distortion Correct viewing distance

B Panoramic Photography Types of panoramic camera Pseudo-panoramic systems Fixed lens panoramic cameras Rotating lens panoramic cameras Spliced panoramas Geometrical implications

C Human Vision Acuity Detail and contrast Field of view Comfortable viewing distance

D Choice of Focal Length Size of image Resolution Field of view and detail

E Taking Good Photographs Camera Film Tripod Levelling Focus Aperture and exposure Recording photographic details

F Earth Curvature and Refraction of Light

157 158 Technical Appendix A

Camera Perspective

Linear Perspective

A1 Leonardo da Vinci wrote, "Perspective is nothing else than seeing a place or objects behind a pane of glass, quite transparent, on which on which the objects which lie behind the glass are to be drawn. These can be traced in pyramids to the point in the eye, and these pyramids are intersected by the glass plane" (Richter and Richter 1939). This description is known as Figure A1: Leonardo’s window as 'Leonardo's window' and is illustrated neatly (if illustrated in Taylor’s ‘New quaintly) by a plate from New Principles of Linear Principles of Linear Perspective’. Perspective by the English mathematician Brook Taylor (Taylor 1719).

A2 In Taylor's diagram, the top corners of a cube, ABCD, are shown projected onto the picture plane as points abcd. Each point on the object is projected onto a corresponding point on the image by a straight line passing through the observer's eye (we have to assume that the other eye is closed for this purpose).

A3 Straight lines in the object are necessarily represented by straight lines in the image. Consider, for example, the line AB. It forms a plane triangle with the observer's eye point O. The intersection of a plane triangle with a plane (in this case the picture plane FGHI) can only be a straight line, so it follows that the projected line ab must also be straight. This property is a characteristic of perspective with a single eye point and a planar picture surface.

A4 The geometry described by Taylor is that found in any textbook on 'measured perspective', the construction of accurate perspective views using drawing instruments (Walters and Bromham 1970). It is also the geometry found in the perspective projections provided by computer graphics software.

159 The Pinhole Camera

A5 The principle of the pinhole camera was known to Leonardo (in the form of the 'camera obscura') and described by him (Richter and Richter 1939). Instead of the rays of light passing through a transparent picture plane to a single eye point, they pass through a single point, the pinhole, to project an image onto the picture plane. As in the case of Leonardo's window, the straight lines followed by the rays of light ensure that straight lines in the object project as straight lines in the image.

A6 A pinhole camera may be constructed quite simply from an empty tin can with a small hole punched in one end and a piece of tracing paper used as a screen. This is in essence the camera obscura used by Figure A2: A simple pinhole some artists in the 17th and 18th centuries as a means camera made from an old tin can. of quickly establishing the perspective of a scene, drawing directly onto paper stretched over the back of the device. The longer the distance between the pinhole and the screen, the larger will be the projected image.

A7 A working photographic pinhole camera may be constructed by replacing the lens of a single-lens reflex camera with a pinhole in the form of a small hole drilled in thin sheet metal and supported on an Figure A3: A pinhole camera improvised by replacing the lens adapted camera body cap. The disadvantage of a of a digital SLR with a modified body cap. pinhole over a lens becomes immediately obvious

Figure A4: Photograph taken with the pinhole ‘lens’ Figure A5: Photograph taken with 50mm lens on the on a digital SLR as shown in Figure A3. same digital SLR.

160 when it is put to use; the pinhole admits very little light, resulting in very long exposure times (up to a 10 seconds) to form an image. The pinhole size determines the sharpness of the image: too large and the image is blurred because each point on the image is illuminated by light from more than a single point in the scene; too small and the diffraction of the light as it passes through the pinhole blurs the image. Even the optimum pinhole diameter of about 0.2mm produces results far inferior to a lens.

Practical Cameras

A8 As mentioned above, the camera obscura was used as a perspective aid by some artists. With just a pinhole, the image would be too faint to use comfortably, particularly if working out of doors, so a lens was used. A good lens behaves in the same way as the pinhole in that the light appears to travel in a straight line from object to image, passing through a point at the centre of the lens. In reality, the light passes through all parts of the lens but is bent by the glass in such a way that light from any given point on the object viewed arrives at a corresponding single point Figure A6: Digital SLR fitted with 50mm focal length lens. on the image, no matter which part of the lens it passes through on the way. As the light can pass through the whole area of the lens, the resulting image is much brighter than with a pinhole.

A9 The earliest photographic cameras constructed by William Fox Talbot in the 1830s were direct adaptations of the camera obscura with chemically sensitised paper in place of the screen for drawing (Arnold 1977).

A10 All modern cameras follow Fox Talbot's basic model of a lightproof box with light passing through a lens and being focussed onto a sensitised surface, either film or an electronic sensor in modern cameras. The quality of the resulting image is largely dependent on the quality and precision of the lens used.

161 Wide angle geometry

A11 Although Leonardo's window must necessarily produce a true perspective as the image exactly overlaps the object, very wide fields of view can nevertheless produce results which are surprising at first glance.

A12 This example was taken with a very wide-angle lens, giving a horizontal field of view of 84° Elements in the scene towards the corners of the frame seem to be elongated and stretched away from the centre of the photograph. However, referring to Brook Taylor's illustration of Leonardo's window, these elements would be seen by the statuesque viewer at a very oblique angle and the foreshortening introduced by this oblique angle exactly compensates for the Figure A7: Photograph taken with equivalent of a 20mm lens on a elongation in the image. (See the section below on 35mm camera, showing viewing distance.) perspective and scale effects of extreme wide angle A13 This elongation of elements in very wide angle images is often referred to as 'distortion'. However it is incorrect to do so as it is simply a consequence of the geometry of linear perspective.

Image Distortion

A14 'Distortion' has a very specific meaning with reference to the properties of camera lenses. There are five classes of monochromatic lens defects (that is, ones that do not affect the colour in an image). Of those, the only one that affects the geometry of the resulting image is 'distortion'. (The others, spherical aberration, Figure A8: Barrel distortion astigmatism, coma and field curvature only affect image sharpness.) Distortion is the phenomenon of straight lines on the objects in a scene being represented by curved lines in the image. If these curves bend outwards from the centre of the image, the lens (and the image) is said to exhibit 'barrel distortion'. If the curves bend inwards, the condition is Figure A9: Pincushion distortion termed 'pincushion distortion'.

162 A15 The best quality fixed focal length lenses are substantially free of distortion. However, wide angle lenses are difficult to make distortion-free and even very good quality examples sometimes have a small amount of barrel distortion.

A16 Zoom lenses are well known to suffer from quite substantial distortion. This is a consequence of the compromises involved in designing a lens which will offer a range of focal lengths and still have a reasonably wide maximum aperture. Typically, a zoom lens will exhibit barrel distortion at the shortest focal length it provides and pincushion distortion at the longest focal length. There may be a point in between where there is effectively no distortion or there may be a combination of pincushion (in the centre of the image field) and barrel (at the edges). Generally, the distortion effects are more pronounced the greater the range of focal lengths provided and are more pronounced on lenses with greater maximum apertures.

A17 With a fixed focal length lens on a digital camera it is possible to calibrate any distortion and remove it by using suitable software.

Correct Viewing Distance

A18 Given a photograph printed on a transparent plastic sheet, it would be possible to go to the location where the camera was set up, to hold the photograph up and to look through it at the actual scene. Clearly, if the photograph is held too close to the eye, the elements in the image will appear too big. If it is held too far away, the elements will appear too small. There will be only one distance at which the photograph will exactly match the real scene. This is usually termed the 'correct Figure A10: Image and scene viewing distance'. Books on geometrical perspective coincide only when viewed from casting tend to use the term 'perspective distance' for the correct viewing distance. the same physical dimension. Brook Taylor used the term 'principal distance' (Taylor 1719) and that term is still used in camera optics.

163 A19 In a pinhole camera, all the light passing through the pinhole really does pass through a single point (or very nearly so, given that the pinhole has a finite size). In a simple (single thickness of glass) thin lens (like a magnifying glass) this is also true. Although the light passes through the whole of the lens, the image formation may be understood as if it converged from the object to the centre of the lens, termed the 'nodal point', and radiated from that point to form an image.

A20 In a camera lens, there are generally four or more separate lens elements, typically bonded together in two groups, with the iris of the lens between them. Generally the point at which light from the image appears to converge, the 'front nodal point', is distinct from the point from which it appears to diverge, the 'rear nodal point'. These points are usually almost coincident in a 50mm focal length standard lens for a 35mm camera.

Figure A11: Optical properties of A21 The principal distance is defined as the distance from a camera and lens. the film plane to the rear nodal point of the lens. Also by definition, when the lens is focussed on infinity, this is also the focal length of the lens. A pinhole camera does not have a focal length as it has no lens, but it does have a principal distance.

A22 Because most landscape photography is done with the lens focussed on infinity, the distinction between focal length and principal distance is sometimes not expressed precisely.

A23 Although a camera projects its image rather than looking through it as Leonardo's window illustration does, the geometry is exactly the same, except that the image is inverted by the light rays crossing over in the lens's nodal points. Leonardo conceptualised the object as being contained by a pyramid with its apex at the observer's eye. Similarly the whole field of view of the camera will be described by a pyramid whose apex is the lens's rear nodal point and whose base is the area of exposed film.

164 A24 As the principal distance is the focal length of the lens (assuming it is focussed at infinity), this is therefore also the correct viewing distance for the image if no enlargement is applied to it. Given a 50mm focal length lens and 35mm film, this would give a 36 x 24mm image to be viewed only 50mm from the eye. Some enlargement is therefore necessary. A simple scaling of all the dimensions involved will preserve all the angles of the pyramid which contains the field of view, so for example, the whole image area scaled up to 350 x 240mm would have a correct viewing distance of 500mm.

A25 In other words, if a photograph is taken with a 50mm lens on a 35mm camera and the whole image is printed on a transparent medium to a size of 360 x 240mm, then standing at the point from which the photograph was taken, it will be possible to hold that print at a distance of 500mm from the eye and see the photographic image exactly line up with the real scene, Similarly, a 180 x 120mm print will line up with the scene at 250mm, but will be too close to focus comfortably for most people, and a 720 x 480mm print will line up at 1000mm, but will be further away than the length of one's arms.

Horizontal Field of View

A26 The horizontal field of view for any camera lens is defined by the focal length of the lens and the width of the image formed (the width of the negative for film cameras or the width of the sensor for digital cameras).

A27 The formula for horizontal field of view is as follows:

 w  A = arctan2    2 f  Figure A12: Calculating the horizontal field of view. where

A is the horizontal field of view in degrees

165 W is the width of the image in millimetres (36mm for 35mm film)

f is the lens focal length in millimetres

arctan is a standard mathematical function (the inverse of the tangent function) and must return degrees in this case.

A28 Examples of horizontal fields of view for a variety of focal lengths in conjunction with 35mm film (with a negative size of 36 x 24mm) are shown in Table 14. Both 'round number' focal lengths and commonly- available focal lengths are shown in Table 18. (Diagonal fields of view are included for completeness as some lens manufacturers quote this as the field of view of their lenses, but the figure is of little practical use.)

166 Table A1: Focal lengths and fields of view Focal length Horizontal Vertical field Diagonal (mm) field of view of view field of view (degrees) (degrees) (degrees)

20 84.0 61.9 94.5 30 61.9 43.6 71.6 40 48.5 33.4 56.8 50 39.6 27.0 46.8 60 33.4 22.6 39.7 70 28.8 19.5 34.3 80 25.4 17.1 30.3 90 22.6 15.2 27.0 100 20.4 13.7 24.4 150 13.7 9.1 16.4 200 10.3 6.9 12.3 250 8.2 5.5 9.9 300 6.9 4.6 8.2

14 104.3 81.2 114.2 18 90.0 67.4 100.5 20 84.0 61.9 94.5 24 73.7 53.1 84.1 28 65.5 46.4 75.4 35 54.4 37.8 63.4 50 39.6 27.0 46.8 85 23.9 16.1 28.6 100 20.4 13.7 24.4 135 15.2 10.2 18.2

167 168 Technical Appendix B

Panoramic Photography

Types of Panoramic Camera

B1 A panoramic camera is one designed to take photographs with a very wide horizontal field of view and an image very wide in relation to its height in comparison with conventional photography. There are two main types of panoramic camera: fixed lens and rotating lens. In addition there are several other photographic systems which are styled in one way or another as 'panoramic' but which can be at best only described as 'pseudo-panoramic'.

Pseudo-Panoramic Systems:

B2 APS (Advanced Photographic System) cameras mostly offer 'panoramic' as one of three settings. All this does is to tag the image to be cropped to a 'letterbox' format. The horizontal field of view is not increased; rather the vertical field of view is restricted. There is no good reason ever to use this setting.

B3 Anamorphic adapters are available to fit to the front of ordinary lenses for 35mm single lens reflex cameras. These work in the same way as the lenses used in some types of widescreen cinematography, squeezing a wide letterbox format into an ordinary 35mm frame. Most squeeze the image by a factor of 1.5 or 2, converting the 3:2 aspect ratio of 35mm to 4.5:2 or 6:2 with a correspondingly increased horizontal field of view (Ray 2002). There is inevitably some image degradation and distortion with these adapters and better results are probably achieved with a very high quality extreme wide-angle lens or by splicing several frames together.

Fixed Lens Panoramic Cameras

B4 There are several makes of fixed-lens panoramic camera. Most are medium format (120 or 220 roll

169 film) but a few are 35mm format. These cameras are really just ordinary cameras with very wide-angle lenses and letterbox aspect ratios. The maximum horizontal field of view offered is about 80° and the perspective is the conventional linear perspective discussed in Appendix A. Consequently, the scale of the image is not constant, with the extreme sides of the Figure B1: Geometry of fixed lens image being significantly enlarged compared to the panoramic camera. This is no different from the geometry of a centre and with a noticeable stretching of shapes conventional camera, except for towards the edges. (There is a corresponding increase extreme field of view and aspect ratio. in scale towards the top and bottom of the image but this is far less noticeable as the vertical field of view is so much less than the horizontal.) Unless the image content is explained carefully, photography made using this type of camera can be misleading.

B5 As was explained in the case of wide-angle single- frame images, as described in Appendix A, if a panorama of this type is viewed from the correct distance, the oblique line of sight to the edges of the

Figure B2: Fuji fixed lens image exactly counterbalance the stretching towards panoramic camera. the edges of the image so that the image looks correct. However, viewed at other distances, the scale variation is very much apparent.

Rotating Lens Panoramic Cameras

B6 Rotating (or swing) lens panoramic cameras are also available. As the name suggests, during exposure, the lens rotates horizontally to pan across the width of the image, which can be up to 150 degrees in some makes. While this is happening, the film is wound past a narrow slit which acts as the shutter. (These cameras are commonly encountered when they are used to take school photographs.)

B7 The result is a very wide photograph with a cylindrical rather than planar projection. That is, the perspective will only be theoretically correct if the photograph is displayed on the inside of a cylinder and viewed from Figure B3: Geometry of rotating lens panoramic camera showing its centre. The correct viewing distance will be the effective cylindrical image surface. radius of the cylinder and will also be the principal

170 distance (or focal length) multiplied by the enlargement ratio of print size to negative size.

B8 The medium format versions of these cameras can produce excellent results. However, owing to the non- standard aspect ratio, it can be difficult to get the resulting negatives printed or scanned. Figure B4: Widelux medium format rotating lens panoramic camera. B9 35mm format rotating lens panoramic cameras are lighter and more portable than their medium format counterparts but can produce disappointing results. The focal length of lens is generally quite short (26mm is common) so the size of image detail is slightly smaller than that captured by a 28mm wide-angle lens on a conventional camera. Also, the finite width of the shutter slit results in a slightly less sharp image than would be obtained with the same focal length lens on a conventional camera. The non-standard aspect ratio makes scanning and printing difficult, as in the case of the medium format cameras. Rotating Figure B5: Noblex 35mm rotating lens panoramic camera. lens panoramic cameras do not in general offer the option to use lenses of different focal lengths as the speed of rotation and speed of film transport are intimately related to focal length.

Spliced Panoramas

B10 Given that panoramic cameras are expensive and cumbersome as well as introducing the technical difficulties in handling the finished photographs which were described above, most practitioners choose to use conventional photography and to assemble panoramas by splicing together sequences of individual frames.

B11 Before the advent of inexpensive scanners and PCs capable of handling large images efficiently, the usual way to assemble a panorama was manually, by physically joining together prints of the individual frames. Anyone undertaking this would rapidly become familiar with the fact that image scale increases towards the edges of the print. There was a

171 considerable knack to finding the point in two adjacent frames where the scale matched and then to make a neat, clean (and irreversible) cut in the print. While it was possible to match the geometry of the images quite accurately this way, differences in brightness and contrast would often show up and repairs to moving clouds or changing lighting conditions were out of the question.

B12 A panorama spliced together out of conventional planar photographs is not strictly a true panorama as it does not form a smooth cylinder. Instead, if each frame were to be set up at the correct viewing distance Figure B6: Panorama spliced and orientation to the observer, it would form a together out of separate frames without transformation to polygon on plan. With sufficient frames, this is not a cylindrical projection

Figure B7: Two adjacent frames overlapped in image editing software ready to splice them together

Figure B8: The splice point has been found and the frames joined together

172 problem in practice and differs only slightly from a true panorama.

B13 With suitable computer image editing software, it is possible to assemble panoramas out of individual frames (either scanned or from a digital camera). The greatest control is obtained by applying a method analogous to the manual method, that is to find corresponding points on adjacent frames where the scale matches and then to crop them at that point. Contrast, brightness and colour balance can be matched quite accurately by eye.

B14 Unless a geometrical transformation is applied to each frame, a panorama assembled digitally will still be a succession of planar panels. Linear elements running across the image, such as overhead wires or kerb lines will kink slightly across each panel boundary. Straight lines in the scene will, however, still project as straight lines.

B15 It is possible to use specialised computer software to transform the geometry of each frame so that it acquires a cylindrical rather than planar perspective. The lens properties need to be known accurately in order to do this. Once transformed, the need to find a point on adjacent frames where the scale matches is obviated; the scale will match correctly everywhere in the region of overlap.

Figure B9: Photograph taken with 50mm lens Figure B10: Photograph transformed to cylindrical projection using software

173 Figure B11: Two adjacent frames transformed and overlapped in image editing software ready to splice them

Figure B12: The splice point can be anywhere in the overlap as the horizontal image scale is constant across both images B16 A wide variety of low-cost panorama-splicing software is available, often bundled free with digital cameras. Most produce superficially convincing panoramas with minimal effort. Left to themselves, they apply a planar- to-cylindrical transformation to each frame, find matching image detail in adjacent frames, colour balance them and then splice them together. The results are not always perfect or even usable. Automatic detection of matching detail is technically difficult to achieve in landscape photographs, where all detail is small and often confusingly similar. If software allows the user to override its choice of splice points, then reasonable control may be applied to the creation of the panorama, if not, then the results will probably not be usable. Most automated panorama

174 software cannot achieve a perfect match across the whole of the area of overlap between frames and disguises this by applying a blurry transition between them. In many cases, this can be obtrusive and visually distracting and may well obscure important areas of detail. The results of an automated splice should be checked carefully and critically. While judicious use of this type of software can produce visually acceptable results, it generally cannot produce the degree of geometrical accuracy needed for the base image for a photomontage.

Geometrical Implications

B17 Planar photographs (conventional single-frame photographs) have a correct viewing distance defined in terms of 'Leonardo's Window' as described in Appendix A. A panorama, on the other hand, is a cylindrical projection rather than a planar one. The equivalent of Leonardo's Window would be a glass cylinder with the eye-point in the centre. A panorama could be constructed in the manner that Leonardo imagined by drawing directly on the cylinder so that Figure B13: A planar image can the lines exactly coincided with the lines scene in the be superimposed on the scene it outside scene. Similarly a panoramic photograph can represents when viewed from the correct viewing distance. be superimposed upon the scene by wrapping it around this cylinder. The superimposition will clearly only work correctly if the cylinder is of the correct diameter. The geometry is similar to planar perspectives in that the correct viewing distance is the principal distance of the lens (often the same as focal length) multiplied by the enlargement factor applied to the print. The correct viewing distance is always the same as the radius of the cylinder.

B18 As in the case of a planar perspective, any straight line Figure B14: A cylindrical segment in the scene will form a plane triangle with panorama can be superimposed on the scene when viewed from the viewer's eye position forming the third vertex. The the centre of curvature of a curved projection of that line segment on the perspective surface whose radius is the correct viewing distance. surface will be defined by the intersection of the triangle with the cylinder described above. With the

175 exception of perfectly vertical or horizontal triangles, the resulting intersection line will always be a curve. A vertical triangle corresponds to a vertical line in the scene and a horizontal triangle to a horizontal line at the same level as the viewer's eye.

Viewing a Panorama

B19 The ideal method of viewing a panorama would be with the image presented as part of a cylinder of the correct radius and then viewed from the centre of that cylinder. Also, ideally, the image should be large enough that viewing comfortably with both eyes is a possibility. This is practical in an exhibition situation, where it would be possible to erect a curved display board several metres wide and to mark a point on the floor for a viewer to stand. Straight lines in the scene, which become curves if the image is laid out flat, look correctly straight when viewed in this way.

B20 Clearly there are many situations where it will be impractical to present a panorama on a curved surface, particularly when a number of panoramas are bound into a document. With care, it is possible to obtain a near-correct view of a cylindrical panorama laid out flat. In the case of a panorama laid flat, the eye point (which would be a single point if the panorama was presented as part of a cylinder), becomes spread out along an imaginary line parallel to the surface of the image and separated from it by the correct viewing distance for the panorama. So long as the gaze is kept perpendicular to the surface of the Figure B15: A panorama can be image, a view from any point along that line will be a viewed from the correct viewing distance even if displayed flat. The good approximation to a correct view. Moving from view must always be one end of this line to the other is geometrically perpendicular to the plane of th image and never oblique. equivalent to standing at the middle of the cylinder and turning one's head to left or right. The reason that this approach works is that the eye is capable of seeing only a small part of a scene in detail (generally taken to be about 6-10° - see Appendix C) and there

176 is not a great deal of difference between a flat and a curved image over that angle.

B21 With a flat panorama, there is always the temptation to stand back so that the whole width of the image may be seen easily. This misrepresents the image in two distinct ways: firstly, viewing from a distance greater than the correct viewing distance will make the image appear too small; secondly, the view obtained will compress the panorama into a narrower field of view than that obtained in reality at the viewpoint location, thus presenting a view that cannot in reality be experienced.

Figure B16: Planar panorama with a horizontal field of view of 106°. This is the type of image produced by a fixed-lens panoramic camera and is equivalent to an extreme wide-angle single frame. The increase in image scale towards the sides of the image are very apparent.

Figure B17: Cylindrical panorama with a horizontal field of view of 106°. This is the type of image produced by a rotating lens panoramic camera or by splicing together single frames from a conventional panorama. The horizontal scale is the same across the whole width of the image. The viewing distances for both panoramas are the same, so the scales are equal in the centre of the planar panorama.

177 Calculating the correct viewing distance

B22 The correct viewing distance is the distance at which the perspective in a photograph (or photomontage) correctly reconstructs the perspective seen from the location from which the photograph was taken. It also follows that, as seen from the correct viewing distance, the photographic image will occupy the same horizontal angle as the horizontal field of view it represents. This is true of both single-frame and panoramic photographs.

B23 The single-frame case is simpler geometrically. Seen from above, the photograph is merely a straight line of length w. We can construct an isosceles triangle with the apex representing the viewpoint and the height of the triangle, d, representing the viewing distance. At the correct viewing distance the apex angle, A, of the triangle must correspond to the horizontal field of view of the photograph. The correct viewing distance is then given by:

d = w    A  2 tan   2    (single frame only)

where:

d is the correct viewing distance in mm w is the image width in mm A is the horizontal field of view in degrees tan is the trigonometric tangent function

B24` If the horizontal field of view and the required viewing distance is known, then the formula rearranges thus to give the image width:

 A  w = 2d tan   2  (single frame only)

B25 Finally, if the image width and viewing distance are known, the formula can also be arranged to give the

178 horizontal field of view. (This version of the formula is useful to determine the horizontal field of view that can be accommodated on a fixed page size.):

 w  A = 2arctan   2d  (single frame only)

B26 In the case of a panorama, the image is assumed to be wrapped around the inside surface of a cylinder whose radius is the correct viewing distance. The horizontal field of view must by definition therefore correspond to the arc of the cylinder subtended by the image.

B27 Given the width of the image and the horizontal field of view, the correct viewing distance is given by:

180w d = πA (panorama only)

where:

d is the correct viewing distance in mm w is the image width in mm A is the horizontal field of view in degrees π has its usual geometrical meaning

B28 Given the viewing distance and the horizontal field of view, the image width is given by:

πAd w = 180 (panorama only)

B29 Lastly, if the image width and viewing distance are known, this formula can also be arranged to give the horizontal field of view:

180w A = πd (panorama only)

179 180 Technical Appendix C

Human Vision

Acuity

C1 Acuity is the ability of the eye to resolve detail. Acuity varies greatly with the brightness of a scene (which corresponds with our everyday experience that fine print is hard to read in dim light). Under bright conditions, the human eye is just able to resolve a pattern of black and white stripes with each stripe covering an angle of 1 minute of arc (1/60 of a degree) (Gregory 1990). The primary reason for this is Structure of the human eye the spacing of the light sensors at the centre of the showing the form of the lens system and the position of its eye's retina rather than limitations of the lens system or nodal points (from Helmholtz diffraction at the pupil, both of which would in Handbuch der Physiologishen Optik 1896). principle allow finer detail to be resolved. (Pirenne 1967).

C2 This figure for acuity does not mean that it is impossible to see objects which are narrower than 1 minute. On the contrary, narrow objects such as overhead wires seen against the sky often subtend narrower angles. The issue is that it is impossible to resolve detail finer than that. Consider, for example, a black-and-white photograph rendered as a halftone for reproduction in a book. The different shades of grey are represented by a pattern of different sizes of black dots on white. At normal viewing distances, the individual dots are not individually resolvable. However, they are not invisible. Each receptor in the eye will receive an image made up of a mixture of several dots and the intervening white paper. The resulting sensation will be indistinguishable from the equivalent shade of grey obtained by mixing the black and white together. The result is that the eye sees shades of grey.

181 Detail and Contrast

C3 Although we speak of seeing an object, our eyes do not see objects directly. Instead, we detect variations in colour and brightness in a scene and from those infer the boundaries of objects which we then recognise as such. In order for this to take place, there must be sufficient contrast to make those edges, and therefore the objects they define, visible. Contrast may be in colour or in brightness, with contrast in brightness being the more important of the two for vision.

C4 There is a trade-off between detail and contrast. Low contrast limits our ability to resolve detail (Pirenne 1967).

Field of View

C5 The human field of view is hard to define meaningfully. The extremes to left and right are controlled by the optical properties of the lens system of the eyes, which together give a horizontal field of view of about 100° either side of centre. The limits upwards and downwards are defined by an individual's skull configuration, but 60° upwards (limited by eyebrows) and 75° downwards (limited by cheeks) are a good average (Pirenne 1967).

C6 Within that very large overall visual field, only a very small central area will be seen in detail. This is the part of the image which falls on the fovea of the eye and is about 6-10° across (Pirenne 1967).

C7 These figures are based on the naïve assumption that a viewer keeps the head motionless and the eyes fixed on a point. In practice, the eyes automatically turn to place the image of any object we look at on the fovea (the 'fixation reflex') (Pirenne 1970). The horizontal field of view naturally turns as the eyes turn. Turning the eyes far from their central position is uncomfortable, so we tend to turn our heads and if necessary our whole bodies to take in a wide view.

182 C8 Various figures in to 45-60° range are often quoted as being representative of the human field of view with regard to illustration or photography. It is certainly true that the majority of photographs, paintings and drawing fall into this range, but there is no physiological justification for that figure.

C9 While it is true that we can only see part of the full 360° around us at any one time and only a small fraction of that clearly at any one time, we move our eyes, heads and bodies as necessary and the overall field of view of which we are aware largely depends on what there is to see.

Comfortable Viewing Distance

C10 The distance at which we can comfortably focus our eyes is largely determined by age. The ability to change focus is known as 'accommodation' and diminishes with time as the lens in the eye stiffens with age. Very young children can focus as close as 70mm, by age 25 the median is about 100mm and over age 50 it is about 500mm (Gregory 1990). Although the loss of accommodation is a lifelong phenomenon, most people have no need to think about using reading spectacles to compensate until middle age.

C11 John Benson's recommendation of a viewing distance of 300-500mm (Benson 2002) therefore represents a compromise. Some older people will probably need to wear reading spectacles to achieve this.

Reproducing the Visual Experience

C12 There are two issues to be considered in reproducing the visual experience either on a screen or on a printed page. One is the resolution of the image to ensure that sufficient detail is captured. The other is the contrast in the image as presented, to ensure that the detail is visible.

C13 Given the known resolution of the average human eye (1 minute of arc) it is in principle possible to specify a

183 specification for image capture and reproduction which would match that.

C14 The calculations are fairly complicated and involve knowing the resolving power of the lens used, the resolving power of the film, resolution (and other parameters) of the scanner and finally the resolution of the printer used (more complicated than a simple dots- per-inch value).

C15 With a film camera, it is theoretically just possible to capture sufficient detail on 35mm film, provided that the lens and film used are of very good quality, the film processing is to the best professional standards and the scanning is carefully carried out at high resolution. However, even the best film can capture only a limited range of contrast, so that the contrast seen in even a good photograph is necessarily very compressed. This naturally limits the detail that can actually be seen in the image.

C16 The resolving power of a digital camera's sensor is determined by the size of the sensor and the number of pixels it contains. Most digital SLRs have a sensor resolving power which exceeds the resolving power of the camera lens, so provided that a high enough resolution is selected, it should be possible to capture sufficient image data. Just as with film, digital camera sensors are limited in the range of contrast they can capture, therefore similarly imposing limits on the detail that can be seen.

C17 (Note that the subsequent operations applied to an image, including transforming to a cylindrical A Snellen chart for assessing visual acuity (one of several test objects projection and colour correction or balancing will all designed by Hermann Snellen). have a small detrimental effect on the detail in the Printed at the correct size and viewed from a distance of 6m, the image.) bars and gaps in the letters in the line DEFPOTEC all subtend 1 min of C18 The required resolution in a finished print is easily arc. Being able to read that line at that distance is the definition of obtained by current photo quality inkjet printers. 20/20 vision (6/6 in metres) and is regarded as average. Many people can read the next line but few the one below that.

184 C19 Reproducing the full contrast range visible in a scene is, in general, impossible. On a bright day outdoors, we may experience a brightness ratio of 1,000:1 between the brightest highlights and the darkest shadows. A very good quality computer monitor has a far more limited range available. The lightest colour displayable is the monitor's maximum white and the darkest is the colour seen when the monitor is switched off, usually a dark grey. The brightness ratio is about 100:1 at best. On a printed image, the range is far less, rarely better than 10:1. Acceptable images can only be produced in these media by making compromises: in order to achieve a good tonal range in the middle of the scale, detail in shadows is lost to black and detail in bright areas may bleach out to white. In practice the eye is extraordinarily tolerant of the degree of contrast compression it will accept as 'realistic' in images of outdoor scenes.

C20 It is possible to trade detail and resolution off against one another, so that if the print resolution is higher than strictly necessary then the contrast between adjacent pixels is likely also to be slightly higher and this will allow the eye to pick out more detail. (Consider the image of a wind turbine at a long distance from the viewpoint. A lower resolution image will have pixels which contain parts of both turbine and background and which are therefore of an intermediate colour and possibly hard to pick out. A higher resolution will allow more pixels to be all turbine or all background and therefore easier to distinguish. Even though the eye may well average

very fine detail together, the fact that the detail is there Snellen chart photographed from makes a difference to the legibility of the image.) 6m with a 50mm lens on a Fuji Finepix S2 digital SLR. The camera Figures 18a, 18b and 18c illustrate this point. has resolved more detail than the photographer could see (he could C21 It is just possible to capture the spatial resolution seen read LEFODPCT). The camera would still not capture the fine detail by the eye using 35mm photography (or equivalent visible in a typical outdoor scene, digital photography) provided great care is taken with owing to inability to reproduce the required contrast range. (This is a the choice of equipment and the procedures used. huge enlargement of a small part However, the detail we see in a scene is a function not of an image, but this does add detail not captured by the camera.)

185 only of the resolution of our eyes but also the very high contrast present in an outdoor scene. No printing or display technology can come close to these levels of contrast, therefore, it is not generally possible to reproduce the levels of detail that would be easily perceptible in a scene.

186 Technical Appendix D

Choice of Focal Length

Size of Image

D1 The main difference that different focal lengths of lens make is to change the size of the image on the film (or sensor). Changing from a 50mm focal length lens to a 100mm lens will exactly double the linear scale of the image. (Other changes in focal length will change the scale proportional to the ratio of focal lengths.) Good lenses should be substantially free of distortions and other defects, so there will not be any other differences in the images: the image taken with the 100mm lens will be the same as the centre portion of that taken with the 50mm lens but enlarged to fill the whole frame. Perspective is uniquely determined by the viewpoint position, and direction of view, so is not influenced by focal length (Ray 2002).

D2 Note that the printed size of an image is independent of the focal length. If an image is defined in terms of its horizontal field of view and its correct viewing distance, then those parameters uniquely define the printed size. The only difference between using the 50mm lens and the 100mm lens from the previous paragraph is that the base image taken with the 50mm lens will have to be enlarged more than would be the case with the 100mm lens.

Resolution

D3 The resolving power of most good-quality fixed focal length lenses is about the same (about 80-100 lines/ mm at optimum aperture. The resolving power of the film or sensor is naturally unchanged irrespective of the lens used (Ray 2002).

D4 However, as the image on the film is larger with a longer focal length, it follows that the level of detail captured is also greater. (Same lines/mm, but each

187 Figure D1: Focal length does not alter perspective

Photograph taken with 28mm lens on digital SLR Photograph taken with 50mm lens on digital SLR

Photograph taken with 135mm lens on digital All three images can be superimposed accurately SLR and differ only in scale, not in perspective.

188 millimetre represents a smaller part of the scene in more detail.) Particularly if very large prints are required, a longer focal length lens might be advantageous in order to improve the level of detail.

Field of View and Detail

D5 The larger image scale of a longer focal length lens is accompanied by a correspondingly smaller field of view. For the overall horizontal field of view in a panorama, this is not a problem; it simply means that for a given field of view there will be more individual frames to be processed and spliced together.

D6 For vertical field of view, it is more problematic as that dimension is inherited from the vertical field of view of a single frame. The consequence can be an undesirable loss of foreground and tops of tall objects in the scene. By setting the camera up in portrait orientation, the vertical field of view can be increased somewhat, at the expense of a slightly more fiddly procedure to do so.

D7 In many cases, however, there will be a choice between detail in the photographs and the field of view obtained and both may be undesirable compromises.

189 190 Technical Appendix E

Taking Good Photographs

E1 This appendix is not intended to be a general manual of photography; there are plenty of good books available on that subject. Rather, it sets out briefly the main issues relating to photography aimed at constructing panoramas suitable for photomontages and ES work.

Camera

E2 A good quality camera is essential. For photography onto film, a 35mm (or medium format) SLR should be used. For digital photography, a digital SLR should be used, ideally one that is based on a 35mm SLR design.

E3 Lenses should be good quality as well; cheap lenses are likely to produce less sharp images. Very fast lenses (f/1.4 or faster) are useful for taking photographs in poor light, but often have poorer Figure E1: Good quality digital SLR camera optical characteristics than slower lenses (f/2 or slower). In particular they sometimes have noticeable barrel distortion.

Film

E4 Very fast film should be avoided as it generally has a coarser grain structure and lower resolving power than slower films. ISO100 colour print film is generally the best choice. Kodak, Fuji and Agfa all produce reliable film at this speed. Avoid budget film or 'own-brand' film, which is generally less satisfactory in image quality and less consistent in performance.

E5 Digital cameras will produce a lot of data when operating at the required resolution, so memory cards of at least 512MB and probably 1GB are likely to be required.

191 Tripod

E6 A stable tripod is essential. As a minimum, a head with independent tilt adjustments for both pitch and roll should be used. (Ball-head tripods cannot be levelled satisfactorily.) Ideally a panoramic head should be used, allowing a single adjustment to be made for an Figure E2: Setting up the tripod. entire panorama. The photographer’s height tends to dictate the camra’s height above ground level under most Levelling circumstances. E7 In order to obtain photographs which will splice together satisfactorily to make a panorama, it is essential that they be levelled accurately. A simple, cheap spirit level will do this quite satisfactorily and, with care, can produce images levelled to an accuracy of about 0.2°. A tripod head with a built-in sprit level and adjusting screws is better. Panorama heads Figure E3:Camera on a always have spirit levels built in. panoramic tripod head. This particular design of head can accept the camera in either Focus landscape or portrait mode. The camera is positioned so that the E8 The camera lens should always be focussed on infinity front nodal point of the lens (the camera’s ‘eye position’) is directly both for consistency and to ensure that the focal length above the axis of rotation of the and principal distance are equal. panoramic head. E9 On auto-focus lenses, the focussing should be set to manual or locked on infinity.

Aperture and Exposure

E10 If at all possible, exposure should be metered once for a complete panorama and then used for all frames either by using a manual setting or by locking the exposure.

E11 For greatest depth of field in the images, aperture Figure E4: Placing a spirit level should be set to the minimum available on the lens against the filter-ring of the (typically f/16 or f/22). If it is necessary to obtain camera lens allows the camera to be levelled accurately. This works slightly more resolution, it may help to use a slightly both for landscape and portrait orientations of the camera. wider aperture: f/5.6 or f/8 are often the optimum settings.

192 E12 Shutter speed should be selected to obtain the correct exposure consistent with the aperture selected. If there are existing wind turbines in the view, the shutter speed will affect the degree of blurring seen in the photograph due to the movement of the blades.

Recording Photographic Details

E13 As a minimum, the following details should be recorded at each viewpoint used as a photo location:

• Position as an OS National Grid Reference. A hand-held GPS receiver is generally sufficient for this purpose. However, take note of the EPE (Estimated Position Error) figure, which is a measure of accuracy, when taking the reading. An EPE of 8m or more may indicate that there was a poor configuration of satellites, possibly because part of the sky is hidden by buildings or landform. If this happens, the EPE may improve by waiting a few minutes or alternatively it may be necessary to change the location. EGNOS and other supplementary technologies may usefully improve the accuracy of GPS.

• Camera lens focal length. This is obvious but important if more than one lens is being used. (On a digital camera, the EXIF data may record this for you.)

• Frame numbers. With film cameras, frame numbers are useful to identify which frames belong to which locations when the film comes back from processing and scanning.

• Camera altitude above OS datum. The GPS altitude should be noted as a check, but in general a more accurate altitude will be obtained by reference to the OS 1:10,000 or 1:25,000 map and estimating from the contours with reference to the features actually visible on site. This will also generally be more accurate than relying on a height interpolated

193

Landscape Character Assessment Guidance for England and Scotland – Topic Paper 6: Techniques and Criteria for judging Capacity and Sensitivity Source: The Countryside Agency

k:\projects\ua005852-mitton road appeal site, whalley\f-reports\title - lca topic 6.docx Page 1

Landscape Character Assessment Guidance for England and Scotland

TOPIC PAPER 6: Techniques and Criteria for Judging Capacity and Sensitivity

An exploration of current thinking about landscape sensitivity and landscape capacity, to stimulate debate and encourage the development of common approaches. Topic paper 6 Techniques and criteria for judging capacity and sensitivity

1. INTRODUCTION 1.1 The Countryside Agency has recently published a report [1] that looks forward to the way that the country- side might evolve up to the year 2020. It makes it clear that change in English rural landscapes is inevitable in the next 20 years, as a result of a variety of social and economic forces, including food production, housing needs, trans- port issues, and energy requirements. At the same time the Agency published the results of a public opinion survey suggesting that 91% of English people want to keep the countryside exactly as it is today. Clearly the two are not compatible and hard decisions are inevitably required about how the many different demands that society makes on the land can be accommodated while also retaining the aspects of the environment that we place such high value on. Although there have been no exactly parallel studies of future landscapes in Scotland and of attitudes to them, the recent report on change in Scotland's rural environment [2] shows that similar issues also arise there. Indeed Scotland has been at the forefront of efforts to consider the capacity of Scotland's landscapes to accommodate change of various types.

1.2 In both England and Scotland, Landscape Character Assessment is being widely employed as a tool to help guide decisions about the allocation and management of land for different types of development. It is being used particu- larly to contribute to sensitivity or capacity studies dealing with the ability of the landscape to accommodate new housing, wind turbines and other forms of renewable energy, and new woodlands and forests, as well as locally signifi- cant types of development such as, for example, aquaculture schemes in Scotland. Work of this type inevitably involves consideration of the sensitivity of different types and areas of landscape and of their capacity to accommo- date change and development of particular types. If carried out effectively, Landscape Character Assessment can, in these circumstances, make an important contribution to finding solutions that allow essential development to take place while at the same time helping to maintain the diverse character and valued qualities of the countryside. Making decisions based on sensitivity and capacity is a difficult and challenging area of work and also one that is developing rapidly as more and more studies of this type are carried out. The terms themselves are difficult to define accurately in a way that would be widely accepted.

1.3 This Topic Paper provides an overview of current thinking about landscape sensitivity and landscape capacity in terms of both the concepts involved and the practical techniques that are being used. It is not intended to provide a definitive method for assessing sensitivity and capacity but rather to help those involved in such work by setting out some of the key principles, clarifying some of the issues, helping with definitions of key terms and providing examples of the approaches that are currently being used. In this way the intention is to encourage greater transparency in the thinking applied to these issues and to promote consistency and rigour in such work. The content of the paper is based on a workshop involving a small group of practitioners involved in work of this type and review of a small selection of recent studies. It was not the intention, and nor were the resources available, to carry out a compre- hensive review of published reports or work in progress in this area, or a wide ranging consultation exercise.

2. WHAT EXISTING GUIDANCE DOCUMENTS SAY ABOUT SENSITIVITY AND CAPACITY 2.1 The topic of landscape sensitivity and capacity proved one of the most difficult to deal with in the main Landscape Character Assessment (LCA) guidance. This was due to both the new and rapidly developing nature of much of this work and also to the great variation in the approaches being applied and the terminology being used. In addition there were some concerns about the need for compatibility with the definitions of sensitivity being devel- oped in the separate 'Guidelines for Landscape and Visual Impact Assessment' [3] which was due to be published at the same time. As a result the published version of the LCA guidance omitted specific reference to landscape sensi- tivity and instead contained only a few short paragraphs on the topic of landscape capacity on the basis that the issues would be dealt with more fully in a later Topic Paper. For convenience, the current wording of the LCA guidance is summarised in Box 1.

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Box 1: What the existing guidance says about capacity "Landscape capacity refers to the degree to which a particular landscape character type or area is able to accommodate change without significant effects on its character, or overall change of landscape character type. Capacity is likely to vary according to the type and nature of change being proposed"

"Many Landscape Character Assessments will be used to help in decisions about the ability of an area to accom- modate change, either as a result of new development or some other form of land use change, such as the introduction of new features, or major change in land cover such as new woodland planting. In these circum- stances judgement must be based on an understanding of the ability of the landscape to accommodate change without significant effects on its character. Criteria for what constitutes significant change need to be identified in planning policies or landscape strategies, and will usually be informed by potential effects on character and/or particular features and elements"

Carys Swanwick and Land Use Consultants. Landscape Character Assessment Guidance. Countryside Agency and Scottish Natural Heritage. 2002.

2.2 The published Guidelines on Landscape and Visual Impact Assessment [3] tackle the subject of sensitivity at some length, but do not deal specifically with the topic of landscape capacity. It is, however, clear that there is much common ground between the thinking that is emerging on landscape sensitivity and capacity in Landscape Character Assessment work and the approach that is taken in Britain to Landscape and Visual Impact Assessment. It is there- fore particularly important to understand the links between the two and to try, as far as possible, to achieve consistency in the approaches used and particularly in the terms and definitions used. On the other hand it must also be recognised that LCA and LVIA are not the same processes and there must also be clarity about the differ- ences between them.

3. CONCEPTS OF SENSITIVITY AND CAPACITY 3.1 The terms sensitivity and capacity are often used more or less interchangeably. Others treat them as opposites, in the sense that low sensitivity is taken to mean high capacity and vice versa. Indeed the earlier versions of the Landscape Character Assessment guidance used the term sensitivity in the definition given above but this was changed to capacity in the published version to avoid confusion with the guidance on landscape and visual impact assessment. However, as experience of the issues involved has developed, it has become clearer that the two are not the same and are not necessarily directly related. A clearer distinction therefore needs to be drawn between them. Definitions vary among those actively engaged in this work and opinions vary about the acceptability and utility of different definitions. The box below contains just two examples of current ideas of sensitivity, in the words of the authors.

Box 2 : Examples of definitions of landscape sensitivity in current use

"Landscape sensitivity... relates to the stability of character, the degree to which that character is robust enough to continue and to be able to recuperate from loss or damage. A landscape with a character of high sensitivity is one that, once lost, would be difficult to restore; a character that, if valued, must be afforded particular care and consideration in order for it to survive."

The model for analysing landscape character sensitivity is based on the following assumptions: i) Within each landscape type certain attributes may play a more significant role than others in defining the character of that landscape. ii) Within each landscape type, certain attributes may be more vulnerable to change than others. iii) Within each landscape type, the degree to which different attributes are replaceable, or may be restored, may vary.

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iv) The condition of the landscape - the degree to which the described character of a particular landscape type is actually present 'on the ground' - will vary within a given area of that landscape type.

By being able to appreciate and assess the significance, vulnerability and replaceability of different attributes, the relative stability or resilience of the various attributes within given landscape types can be assessed. Then, taking into account condition, or representation of character, the sensitivity of a particular area of landscape can be determined.

Chris Bray. Worcestershire County Council. Unpublished paper on a County Wide Assessment of Landscape Sensitivity. 2003.

Landscape sensitivity... is a property of a thing that can be described and assessed. It signifies something about the behaviour of a system subjected to pressures or stimuli. One system, when stimulated might be robust and insensitive to the pressure, whilst another may be easily perturbed. The system might also be thought of in a dynamic way - the pressure could send the system off into a new state or the system might be resilient and bounce back rapidly and be relatively insensitive to disturbance. Sensitivity is related here to landscape charac- ter and how vulnerable this is to change. In this project change relates to wind energy development and any findings on landscape sensitivity are restricted to this (landscapes may have different sensitivities to other forms of change or development). Landscapes which are highly sensitive are at risk of having their key characteristics fundamentally altered by development, leading to a change to a different landscape character i.e. one with a different set of key characteristics. Sensitivity is assessed by considering the physical characteristics and the perceptual characteristics of landscapes in the light of particular forms of development.

John Benson et al. University of Newcastle. Landscape Capacity Study for Wind Energy Development in the Western Isles. Report commissioned by Scottish Natural Heritage for the Western Isles Alternative Renewable Energy Project. 2003

3.2 These two examples highlight one of the main debates about landscape sensitivity, namely whether it is realistic to consider landscapes to be inherently sensitive or whether they can only be sensitive to a specific external pressure. This paper argues that both are valid and useful in different circumstances. Looking at the way that the word sensitivity is used in other contexts, for example in describing the character of people, it is common and seems quite acceptable to describe someone as 'a sensitive person', without necessarily specifying what they are sensitive to. Landscape can quite reasonably be treated in the same way.

3.3 There is a greater degree of agreement about definitions of capacity with broad acceptance that it is concerned with the amount of change or pressure that can be accommodated. There is therefore a quantitative dimension to it and it needs to reflect the idea of the limits to acceptable change. The main debate here is about whether aspects of landscape value should or should not be incorporated into considerations of capacity. In general there appears to be some acceptance that it should, although some argue that this is a retrograde step and could lead to an over reliance on existing designations, which is widely recognised as an overly simplistic approach. There is also some disagree- ment about where visual aspects should be considered, whether as a component of landscape sensitivity, or wholly as a contributor to landscape capacity, or both.

3.4 In this paper an attempt has been made to weigh up the different arguments and as a result it is suggested that three terms can usefully be adopted as shown below. Further details of the definition and use of these terms are in the later sections of this paper. i) Overall landscape sensitivity:This term should be used to refer primarily to the inherent sensitivity of the landscape itself, irrespective of the type of change that may be under consideration. It is likely to be most relevant in work at the strategic level, for example in preparation of regional and sub-regional spatial strategies.

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Relating it to the definitions used in Landscape and Visual Impact Assessment, landscape sensitivity can be defined as embracing a combination of:

• the sensitivity of the landscape resource (in terms of both its character as a whole and the individual elements contributing to character); • the visual sensitivity of the landscape, assessed in terms of a combination of factors such as views, visibility, the number and nature of people perceiving the landscape and the scope to mitigate visual impact. ii) Landscape sensitivity to a specific type of change:This term should be used where it is necessary to assess the sensitivity of the landscape to a particular type of change or development. It should be defined in terms of the interactions between the landscape itself, the way that it is perceived and the particular nature of the type of change or development in question. iii) Landscape capacity:This term should be used to describe the ability of a landscape to accommodate different amounts of change or development of a specific type. This should reflect:

• the inherent sensitivity of the landscape itself, but more specifically its sensitivity to the particular type of development in question, as in (i) and (ii). This means that capacity will reflect both the sensitivity of the landscape resource and its visual sensitivity; • the value attached to the landscape or to specific elements in it.

The meanings of these terms and the types of factors that need to be considered in each case are summarised in Figure 1 (a) and (b).

Landscape Character Sensitivity

Based on judgements about sensitivity of: Natural Factors Vegetations types Visual Sensitivity Tree cover type/pattern Extent and pattern of semi-natural habitat General visibility Cultural Factors Land form influences Overall Land use Tree and woodland cover Settlement pattern Landscape =+Field boundaries Population Sensitivity Enclosure pattern Numbers and types of Time depth residents Landscape Quality/Condition Numbers and types of Intactness visitors Representation of typical Character State of repair of individual elements Mitigation Potential Used in strategic Aesthetic Factors Scope for mitigating Scale potential visual impacts applications and Enclosure does not deal Diversity Texture with particular Pattern types of change or Colour development. Form/Line Balance Figure 1(a): Summary of Movement factors to consider in judging overall landscape sensitivity

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Landscape Character Visual Landscape Sensitivity Sensitivity Value

Landscape Based on judgements Based on nature of Designations Capacity to = about sensitivity of change and inter- + National accommodate aspects most likely to + action with visual Local be affected e.g. aspects of landscape specific type of e.g. Other Criteria change Natural Factors General visibility indicating value Extent and pattern of Land form influences Tranquillity semi-natural habitat Tree and woodland Remoteness cover Wildness Cultural Factors Scenic Beauty Need to specify key Land use Population Cultural Associations aspects of the specific Enclosure pattern Numbers and types of Conservation residents interests change or development Landscape Numbers and types of Consensus on value that are likely to have an Quality/Condition visitors impact on the landscape. Representation of typ- ical Character Mitigation Potential Scope for mitigating e.g. For turbines: Aesthetic Factors potential visual Tall structures Scale impacts Moving structures Enclosure Clusters from 1-3 to 10-50 Pattern Form/Line Access roads and Movement Figure 1(b): Summary of factors to consider low level structures Potential intervisibility in judging landscape capacity for a particular type of change.

3.5 The implication of this is that capacity studies must be specific to a particular type of change or development. At a strategic level, for example in work relating to regional and sub-regional spatial strategies, this means that it might be appropriate to produce a single map of general landscape sensitivity. Maps of landscape capacity, however, need to be specific so that, for example, a map showing an assessment of wind turbine capacity could be produced but would almost certainly be different from a map showing capacity for housing development or for new woodland and forestry planting. Some capacity studies are very specific in their purpose, seeking for example to assess capacity to accommodate a 1000 home settlement at a particular density of development.

4. JUDGING OVERALL LANDSCAPE SENSITIVITY 4.1 In making judgements about the overall landscape sensitivity of different landscape types or areas, without refer- ence to any specific change or type of development (for example in work relating to regional and sub-regional spatial strategies), careful consideration needs to be given to two aspects:

• Judging the sensitivity of the landscape as a whole, in terms of its overall character, its quality and condition, the aesthetic aspects of its character, and also the sensitivity of individual elements contributing to the landscape. This can be usefully referred to as landscape character sensitivity; • Judging the visual sensitivity of the landscape, in terms of its general visibility and the potential scope to mitigate the visual effects of any change that might take place. Visibility will be a function particularly of the landform of a particular type of landscape and of the presence of potentially screening land cover, especially trees and woodland. It will also be a reflection of the numbers of people who are likely to perceive the landscape and any changes that occur in it, whether they are residents or visitors.

Landscape character sensitivity 4.2 Judging landscape character sensitivity requires professional judgement about the degree to which the landscape in question is robust, in that it is able to accommodate change without adverse impacts on character. This means

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making decisions about whether or not significant characteristic elements of the landscape will be liable to loss through disturbance, whether or not they could easily be restored, and whether important aesthetic aspects of character will be liable to change. Equally, consideration must be given to the addition of new elements, which may also have a significant influence on character. These decisions need clear and consistent thought about three factors:

• the individual elements that contribute to character, their significance and their vulnerability to change; • the overall quality and condition of the landscape in terms of its intactness, representation of typical character and condition or state of repair of individual elements contributing to character; • the aesthetic aspects of landscape character, noting that in Scotland these are usually referred to as the 'landscape experience' or the 'scenic qualities' of the landscape. As indicated in the LCA Guidance, aesthetic factors/scenic qualities can still be "recorded in a rational, rigorous and standardised, if not wholly objective way". They include for example the scale, level of enclosure, diversity, colour, form, line, pattern and texture of the landscape. All of these aesthetic dimensions of landscape character may have significance for judgements about sensitivity. They are also distinct from the perceptual aspects of landscape character, which are much more subjective and where responses to them will be more personal and coloured by the experience and the preferences of the individual. These are also important dimensions of character and influence the ability of landscapes to accommodate change but they are best dealt with as part of the consideration of value to be incorporated in the final step of assessing capacity, as discussed in Section 7.

4.3 Different methods have been used to judge landscape character sensitivity in recent work. Each has its merits and it is not the role of this topic paper to advocate one approach or another. There is also much common ground between them and they are not therefore alternatives but rather different explorations of a similar approach. A common feature of these approaches in England is the analysis of landscape character in terms of firstly the natural and ecological, and secondly the cultural attributes of the landscape. Landscape sensitivity is in these cases equated broadly with ideas of ecological and cultural sensitivity and deliberately does not embrace either aesthetic aspects of character or visual sensitivity. Three recent examples illustrating this approach are summarised in Boxes 3 and 4.

4.4 There are few if any examples of studies of overall landscape sensitivity that incorporate assessment of the aesthetic dimensions of landscape character, although it would be technically possible to do this. Such considerations are more likely to be found in studies of sensitivity to particular forms of change or development and are discussed in Section 5.

Box 3: An approach based on ecological and cultural sensitivity

The Countryside Agency's work on traffic impacts on the landscape required a desk based rather than a field assessment using Staffordshire as the test area. The main concern was with the impact of the road network on landscape character. The Countryside Agency's National Landscape Character Types, and the Land Description Units (LDUs) on which they are based, both derived from the National Landscape Typology, were used as reporting units. The attribute maps from the national typology also provided much of the source data for the analysis. In this work landscape sensitivity is defined as the degree to which the character of the landscape is likely to be adversely affected or changed by traffic levels and network use. It is considered to consist of a combination of ecological sensitivity and cultural sensitivity where:

• ecological sensitivity is based on identification of areas where there are ecologically significant habitats likely to be at risk, reflecting combinations of agricultural potential, related to ground type, together with agricultural use and woodland pattern; • cultural sensitivity is based on identification of areas where culturally significant elements of the landscape will be at risk, reflecting a combination of settlement pattern, land cover and the origins of the landscape in terms of whether it is 'planned' or 'organic'.

These two aspects of sensitivity are mapped using GIS and combined into an overall sensitivity matrix. Data on

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the road hierarchy and road 'windy-ness' was then combined with the sensitivity classes to give an overall assessment. This desk study proves successful in highlighting areas of concern that could then be examined in more detail if required.

Babtie Group and Mark Diacono. Assessing Traffic Impacts on the Countryside. Unpublished Report to the Countryside Agency. 2003.

Box 4 :Approaches based on vulnerability, tolerance and resilience to change

Work carried out recently for structure plan purposes by Herefordshire and Worcestershire County Councils working in partnership, focuses on landscape character sensitivity rather than visual sensitivity. The work is at the detailed level of Land Description Units (the constituent parts or building blocks of Landscape Character Types and Areas). These studies also focus on individual landscape indicators and attributes - meaning the factors that contribute to character, grouped together under the headings of ground vegetation, land use, field boundaries, tree cover character, tree cover pattern, enclosure pattern, settlement pattern, spatial character and additional characteristic features, such as parkland or rivers.

These studies use a combination of several different aspects of the character of the landscape to reach an assessment of overall sensitivity, based on analysis of these attributes. The definitions of the component parts can be summarised as follows:

Vulnerability: This is a measure of the significance of the attributes that define character, in relation to the likelihood of their loss or demise. This combines assessment of the significance of an attribute with assessment of its functionality and of the likelihood of future change based on apparent trends.

Tolerance: This can be defined as the degree to which change is likely to cause irreparable damage to the essential components that contribute to landscape character. It is a measure of the impacts on character of the loss of attributes, reflecting the timescale needed for their contribution to character to be restored. This combines assessment of the replaceability of individual attributes with their overall significance in the landscape and also takes account of the potential for future change based on apparent trends.

Resilience: This combines tolerance with vulnerability to change. It is a measure of the endurance of landscape character, representing the likelihood of change in relation to the degree to which the landscape is able to tolerate that change.

Sensitivity: Relates to the resilience of a particular area of landscape to its condition.

Each of these aspects of sensitivity is assessed from a combination of desk and fieldwork. The assessments of each factor are then progressively combined in pairs using matrices, until the final assessment of individual areas emerges. In general three point numerical scores are used to combine the various aspects in pairs.

The published Herefordshire work focuses on landscape resilience , which is mapped for landscape types and forms the key summary map in the published Supplementary Planning Guidance document, leaving a final assess- ment of sensitivity to a more detailed stage based on individual land cover parcels, which is the fine grain at which condition has been assessed in this work. The Worcestershire work is not yet published but will take a similar approach once the County survey of condition has been completed.

Worcestershire County Council. Unpublished paper on a County Wide Assessment of Landscape Sensitivity. 2003. Herefordshire Council. Landscape Character Assessment. Supplementary Planning Guidance. 2002.

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Visual sensitivity 4.5 In a comprehensive study of landscape sensitivity account would ideally also be taken of the visual sensitivity of the landscape. This requires careful thinking about the way that people see the landscape. This depends on:

• the probability of change in the landscape being highly visible, based particularly on the nature of the landform and the extent of tree cover both of which have a major bearing on visibility; • the numbers of people likely to perceive any changes and their reasons for being in the landscape, for example as residents, as residents staying in the area, as travellers passing through, as visitors engaged in recreation or as people working there; • the likelihood that change could be mitigated, without the mitigation measures in themselves having an adverse effect (for example, planting trees to screen development in an open, upland landscape could have as great an effect as the development itself).

4.6 In practice visual sensitivity can be difficult to judge without reference to a specific form of change or develop- ment and that is no doubt why there are few examples of strategic assessments that incorporate this dimension. Herefordshire and Worcestershire initially intended to incorporate such considerations into their strategic work but abandoned the attempt on the basis that it was more realistically considered for specific proposed developments or change. Work by Staffordshire County Council does, however, provide a working example of an approach that combines judgements about landscape character sensitivity (as outlined above) with consideration of the issue of visual sensitivity. It is summarised in Box 5.

Box 5: Staffordshire County - An approach that combines landscape character sensitivity and visual sensitivity Work carried out by Staffordshire County Council, published as Supplementary Planning Guidance to the Staffordshire and Stoke on Trent Structure Plan , approaches landscape sensitivity by working at the Land Description Unit level and addressing the three aspects of landscape character listed below. In this work the first stage in addressing landscape sensitivity is to consider the quality (as defined in the LCA guidance, meaning condition and expression of typical character in specific areas) of individual areas of landscape in relation to their character. This is achieved by asking a series of questions about the three aspects of character:

• Visual aspects, dealing with the spatial distribution, pattern and condition of landscape elements. The questions cover: the presence of characteristic features for the landscape type; the absence of incongruous features for the type; and the visual and functional condition of the elements contributing to character of that particular type. • Cultural aspects, which are determined by the history of human activity and are reflected in the patterns of settlement, land use, field enclosure and communications. The questions cover: demonstration of a clear and consistent pattern of landscape elements resulting from a particular course of historical development contributing to character; and the extent to which the area exhibits chronological continuity or 'time depth' in the landscape. • Ecological aspects, relating to the pattern and extent of survival of the typical semi-natural vegetation and related fauna. The questions cover the presence and frequency of semi-natural vegetation character- istic of the landscape type; and the degree of fragmentation and the pattern of the semi-natural habitats.

The Staffordshire approach notes the strong relationship between the quality and sensitivity of the landscape in that one of the effects of disturbance can be the removal of characteristic landscape features. In dealing with the potential impacts of change on landscape character it asks how likely it is that significant features or charac- teristics of the landscape that contribute to its quality will be lost through disturbance. It also asks whether perception of landscape quality will be adversely affected.

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Landscape sensitivity Potential for mitigation Potential for mitigation of of effects on landscape visual effects character

General Tranquillity Landscape landscape condition visibility

Visibility as Visibility as Strength of visual controlled by controlled by expression of character landcover landform

The Staffordshire example is one of the few cases where landscape character sensitivity and visual sensitivity have been combined in an integrated approach. In terms of visual impact this work asks two questions:

• How likely is it that the effects of a given amount of disturbance will be visible? • What is the potential for negating or minimising adverse visual impacts of disturbance through mitigation and compensation measures?

The idea of general visibility is used and is defined in terms of the likelihood that a given feature, randomly located, will be visible from a given viewpoint, also randomly located. It was determined in this case by theoreti- cal and field based analysis of landform and tree and woodland cover and the way that they interact.

All these different factors, relating to both landscape character sensitivity and visual sensitivity are then combined by judging each on a 5 level scale and combining them sequentially, in map form, through the use of GIS, to produce a final map of landscape sensitivity.

Staffordshire County Council 1999. Planning for Landscape Change. Supplementary Planning Guidance to the Stoke on Trent and Staffordshire Structure Plan. 1996-2011

5. JUDGING LANDSCAPE SENSITIVITY TO A SPECIFIC TYPE OF CHANGE 5.1 In many studies judgements must be made about the ability of the landscape to accommodate particular types of change or development. This is where sensitivity and capacity are most often used interchangeably but it is suggested that, in line with the definitions set out above, sensitivity is the most appropriate word to use. When judging how sensitive a landscape is to some specified type of change it is essential to think in an integrated way about:

• The exact form and nature of the change that is proposed to take place; • The particular aspects of the landscape likely to be affected by the change, including aspects of both landscape character sensitivity and visual sensitivity, as described in Section 4.

5.2 Understanding the nature of the agent of change is like specifying or describing the development project in an Environmental Impact Assessment, except that it is a generic rather than a project-specific form of change. The focus must be on identifying key aspects of the change that are likely to affect the landscape.

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5.3 Defining the particular aspects of the character of the landscape that are likely to be affected by a particular type of change (landscape character sensitivity) means careful analysis of the potential interactions. These might include: impacts upon particular aspects of landscape character including landform, land cover, enclosure and settle- ment pattern; and impacts on aesthetic aspects such as the scale, pattern, movement and complexity of the landscape. In Scotland, for example, the wide range of capacity studies that have been carried out , although varying in their approach, usually incorporate consideration of the key physical, natural and cultural characteristics of the landscape, but also take into account the aesthetic/scenic dimensions of the landscape in judgements about the ability of different landscapes to accommodate change. So, for example, the Stirling Landscape Character Assessment, which includes consideration of a locational strategy for new development, includes criteria related to the 'landscape experience'. It considers that scale, openness, diversity, form and or line, and pattern are the most relevant aspects for this task (see Box 6 in Section 7 for fuller examples).

5.4 Similarly the visual sensitivity of the landscape with respect to the specific type of change or development needs to be assessed. This means that the potential visibility of the development must be considered, together with the number of people of different types who are likely to see it and the scope to modify visual impacts by various appro- priate forms of mitigation measures.

5.5 An overall assessment of sensitivity to the specific form of change or development requires that the four sets of considerations summarised above should be brought together so that the sensitivity of individual types or areas of landscape to that particular form of development can be judged and mapped. They are:

• impacts upon particular aspects of landscape character including landform, land cover, enclosure and settlement pattern; • impacts on aesthetic aspects such as the scale, pattern, movement and complexity of the landscape; • potential visibility of the development and the number of people of different types who are likely to see it; • scope to modify visual impacts by various appropriate forms of mitigation measures.

In most cases, this is likely to be a precursor to further judgements about capacity. Studies specifically of sensitivity to a particular type of development, without proceeding to an assessment of capacity, are not likely to be common.

5.6 The outcome of a study of landscape sensitivity to a specific type of change or development would usually be a map of different categories of sensitivity, usually with either three (for example low, medium and high) or five (for example very low, low, medium, high, very high) categories of sensitivity. Such a map provides an overview of areas where there is relatively low sensitivity to the particular type of change or development but does not indicate whether and to what extent such change or development would be acceptable in these areas. This requires consid- eration of other factors and is best tackled through a landscape capacity study.

BOX 5: South West Region Renewable Energy Strategy - an example of using landscape sensitivity to forms of renewable energy development to inform draft targets This is a consultant's study, carried out by Land Use Consultants for the Government Office for the South West. It focussed on providing information on the sensitivity of different landscape character areas to wind turbines but also assessed whether a similar approach could be used for biomass crops. Key features of this work, which is still in progress, are:

• It is a strategic study of landscape sensitivity to a specific type of change/development. The Countryside Character Area framework is adopted as suited to the needs of regional scale work, though there has also been subsequent discussion of the scope to use the new National Landscape Typology to provide a more refined level of assessment. • A range of attributes contributing to landscape character are identified as likely to indicate suitability to accommodate wind turbines. Scale and form of the landscape, landscape pattern, settlement pattern and

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transport network relate to the elements and attributes giving character to the landscape; skylines and inter-visibility relate to the visual sensitivity of the landscape; sense of enclosure, sense of tranquillity and remoteness relate to perceptual aspects and value; while sensitive/rare landscape features relates to aspects of landscape value. These distinctions are not referred to in the study where all are referred to simply as 'landscape attributes'. • A shorter list of attributes is considered to indicate suitability of a landscape to accommodate biomass crops. They are: landscape pattern, land cover/land use, sense of enclosure and settlement pattern/ transport network. • Using these attributes, a series of sensitivity classes are defined in relation to both wind turbines and biomass crops. In each case a five level verbal scale of sensitivity is used - low, moderate/low, moderate, moderate/high and high. • For each level of sensitivity the influence of the landscape attributes in relation to that type of develop ment is summarised. For example, landscapes judged to be of low sensitivity to wind turbines are "likely to have strong landform, a strong sense of enclosure that reduces visual sensitivity, to be already affected by man made features, to have reduced tranquillity, little inter-visibility with adjacent landscapes and a low density of sensitive landscape features. Similarly, for biomass crops, areas of high sensitivity are defined as those where monocultures of biomass crops would prejudice landscape pattern, where transport infra structure is dominated by narrow rural lanes (or is absent), and where buildings are uncharacteristic of the landscape (e.g. moorland). The scale of possible wind turbine development is considered, predominantly in relation to landform scale, though it is acknowledged that at more detailed levels of assessment other factors such as landscape pattern and enclosure will also be relevant.

Overall the assessment of landscape sensitivity is considered to provide just one 'layer' of information relevant to the process of regional target setting. The study is clearly based on professional judgement within a clear and reasonably transparent framework. There is no explicit scoring or use of matrices but rather a common sense approach to combining the nature of the landscape with the nature of the development to derive sensitivity classes.

Land Use Consultants. South West Renewable Energy Strategy: Using Landscape Sensitivity to set Draft Targets for Wind Energy. Unpublished report to the Government Office for the South West. 2003.

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6. JUDGING LANDSCAPE CAPACITY 6.1 Turning a sensitivity study into an assessment of capacity to accommodate a particular type of change means taking a further step. The assessment of the sensitivity of different types or areas of landscape to the type of change in question must be combined with an assessment of the more subjective, experiential or perceptual aspects of the landscape and of the value attached to the landscape. There are, perhaps inevitably, some reservations amongst practitioners about the incorporation of value in work on landscape sensitivity and capacity because this is seen as the return to the now largely discredited thinking about landscape evaluation. It cannot be denied, however, that society does value certain landscapes for a variety of different reasons and this has, in some way, to be reflected in decision making about capacity to accept change.

6.2 As the Landscape Character Assessment guidance indicates (Paragraph 9.5), value may be formally recognised through the application of some form of national landscape designation. Where this is the case the implications of the designation need to be taken into account. This means, in particular, understanding what aspects of the landscape led to its designation and how these might be affected by the proposed change. The consultation draft of Planning Policy Statement 7, which is due to replace Planning Policy Guidance Note 7, requires that Local Planning Authorities no longer refer to local landscape designations in Development Plans. Local landscape designations are proposed to be replaced by criteria-based policies, underpinned by robust Landscape Character Assessments.

6.3 The absence of designation does not mean that landscapes are not valued by different communities of interest. This means that in such cases other indicators of value will need to be considered to help in thinking about capacity. Judgements about value in such cases may be based on two main approaches. One is to address value by means of the Quality of Life Assessment approach, seeking to address the question of 'What Matters and Why?' (see Topic Paper 2 - 'Links to Other Sustainability Tools'). In this approach value will be judged in an integrated way, with considerations of landscape and sense of place set alongside other matters such as biodiversity, historic and cultural aspects, access and broader social, economic and environmental benefits.

6.4 Alternatively judgements can be made in terms of the relative value attached to different landscapes by a range of different communities of interest. This can be based on the range of criteria set out in the Landscape Character Assessment guidance (Paragraphs 7.8 and 7.22). These include landscape quality and condition; perceptual aspects such as scenic beauty, tranquillity, rurality, remoteness or wildness; special cultural associations; the presence and influ- ence of other conservation interests. There may also be a long established consensus about the importance of particular areas. Weighing up all these factors may allow the relative value of particular landscapes to be assessed as an input to judgements about capacity.

6.5 Reaching conclusions about capacity means making a judgement about the amount of change of a particular type that can be accommodated without having unacceptable adverse effects on the character of the landscape, or the way that it is perceived, and without compromising the values attached to it. This step must clearly recognise that a valued landscape, whether nationally designated or not, does not automatically, and by definition, have high sensitivity. Similarly and as already argued in Section 3, landscapes with high sensitivity do not automatically have no, or low capacity to accommodate change, and landscapes of low sensitivity do not automatically have high capacity to accept change. Capacity is all a question of the interaction between the sensitivity of the landscape, the type and amount of change, and the way that the landscape is valued.

6.6 It is entirely possible for a valued landscape to be relatively insensitive to the particular type of development in question because of both the characteristics of the landscape itself and the nature of the development. It may also be the case that the reasons why value is attached to the landscape are not compromised by the particular form of change. Such a landscape may therefore have some capacity to accommodate change, especially if the appropriate, and hopefully standard, steps are taken in terms of siting, layout and design of the change or development in question. For example, a capacity study may show that a certain specified amount of appropriately located and well-designed housing may be quite acceptable even in a highly valued and moderately sensitive landscape. This is why capacity is such a complex issue and why most capacity studies need to be accompanied by guidelines about the ways in which certain types of change or development can best be accommodated without unacceptable adverse effects.

12 Topic paper 6 Techniques and criteria for judging capacity and sensitivity

6.7 Clearly at this stage of making judgements about capacity there can be considerable benefit in involving a wide range of stakeholders in the discussions since there is likely to be a strong political dimension to such judgements. On the other hand clear and transparent arguments are vital if decisions are to be well founded and this is where well constructed professional judgements about both sensitivity and capacity are extremely important.

6.8 In Scotland a wide range of capacity studies have been carried out to look at the ability of different areas to accept development of different types. They have covered housing and built development in general, as well as wind turbines and aquaculture. The detailed approach taken varies as the studies have been carried out by different individuals or consultancies working to different briefs for different clients. Box 6 contains a summary of the approach taken in a recent example.

BOX 6 : Stirling Landscape Capacity Assessment for Housing and Small-scale Industrial, Retail and Business Development

Carried out by David Tyldesley Associates for Scottish Natural Heritage and Stirling Council in 1999, this study seeks to ensure that development around Stirling is directed towards those landscapes which can best accom- modate it. The work developed an approach pioneered at St Andrews in 1996 and also ran in parallel with a settlement capacity evaluation in the neighbouring area of Clackmannanshire. The Stirling study assessed 15 specific locations of settlements and their settings and three larger general areas of search. The purpose of the study was to define: settlements and areas of high landscape sensitivity judged to have little capacity to accom- modate growth; settlements and areas judged to be able to accommodate minor growth and settlements or areas judged to be suitable for major settlement expansion or new settlement. The work assumed that the buildings in question would be well-designed and would use traditional building techniques and materials. It also assumed that it would include a strong framework of structural landscape treatment including ground modelling where appropriate and tree planting of appropriate scale, area, design and species composition to ensure that the development achieves a good fit in the landscape. This study embraces both sensitivity and capacity, as defined in this Topic Paper, although they are not separately considered. The assessment is clearly made with respect to particular specified forms of development. The assessment is based on five criteria which are applied to the landscape types previously identified in a Landscape Character Assessment. The five criteria address aspects of Landscape Character Sensitivity,Visual Sensitivity and Landscape Value, as discussed in this topic paper. The criteria are derived from the key characteristics and features of the landscape character types and can be grouped as follows in relation to the structure of this Topic paper:

Related to Landscape Character Sensitivity

Effects on the Landscape Resource: examines the effects of development on the key physical features and characteristics and judges whether that development of the kind described could be accommodated and whether the character of the landscape would be sustained, enhanced or diminished. Only the important characteristics relevant to the type of development are assessed.

Effects on the landscape experience: assesses the potential effects of development on aspects of landscape experience relating to scale, openness, diversity, form and/or line and pattern and makes an overall assessment of whether these aspects would be affected positively or negatively.

Related to Visual Sensitivity

Visual effects: considers possible visual effects of the forms of development on: views and approaches to the settlements from the principal approach roads; possible effects on strategically significant outward views from the settlements; potential effects on distinctive skylines; and potential effects on visually conspicuous locations such as open, flat ground or open, high or rising ground.

13 Topic paper 6 Techniques and criteria for judging capacity and sensitivity

Mitigation: considers whether the development would require long-term mitigation to reduce the effects of the development. It also considers how feasible any desirable mitigation would be and whether the mitigation itself would be appropriate.

Related to Landscape Value

Other Important Effects: considers whether the development would affect the integrity of an important designed landscape or its setting and whether the development would affect the amenity of other important cultural or historical elements or features of the landscape, including their settings.

The criteria under these five categories are applied systematically to each settlement and area of search in terms of the different landscape character types that occur. Professional judgments are made and for each crite- ria a three point graphical scale is used to express the findings. An overview is taken of the judgments for each of the criteria for each landscape type, and an overview assessment is made of the whole. The three point scale applied to each criteria covers: no impact or positive enhancement; neutral or average effect; and significant negative effect or diminishing of landscape character. An overall judgment is then made based on the profile of the area/settlements and relevant landscape type based on a table of judgments under each criteria.

David Tyldesley Associates. Stirling Landscape Character Assessment. Report for Scottish Natural Heritage and Stirling Council. 1999

7. RECORDING AND PRESENTING INFORMATION 7.1 Approaches to judging sensitivity and capacity can be made at different levels of detail. Much depends on the time and resources available and on the problem to be addressed. For example, capacity studies for housing may need a finer grain of assessment because of the particular nature of the development. Where time and resources are limited quick assessments are needed and it is likely that overall judgements will need to be made about the whole of a landscape type or area without necessarily making individual assessments of the constituent aspects of sensitivity or capacity. Consultants working to tight timescales and with limited budgets often carry out short sharp studies of this type. In such cases it is rarely possible to assess each of the relevant factors individually in great detail and the emphasis is often on overall judgement of sensitivity. It is nevertheless still extremely important that the thinking that underpins these judgements is clear and consistent, that records of the field judgements are kept in a consistent form and that the decisions reached can be explained easily to an audience of non-experts.

7.2 Local authorities carrying out such work in house are likely to work in a different way and may sometimes have longer periods of time for desk study, survey and analysis. Permanent staff can be more fully involved in such studies and have a greater opportunity to become familiar with and to understand their landscapes and to develop real ownership of the work. In these cases it may be possible to take a much more detailed and transparent step-by-step approach to assembling the judgements that ultimately leads to an overall assessment of landscape sensitivity or capacity. The Staffordshire,Worcestershire and Herefordshire studies, for example, provide demonstrations of what can be achieved by officers working on assessing their own areas, often over a reasonably long period of time.

7.3 Whoever carries them out, all assessments of sensitivity and capacity inevitably rely primarily on professional judgements, although wherever practically possible they should also include input from stakeholders. The temptation to suggest objectivity in such professional judgements, by resorting to quantitative methods of recording them is generally to be avoided. Nevertheless dealing with such a wide range of factors, as outlined in the paragraphs above, does usually require some sort of codification of the judgements that are made at each stage as well as a way of combining layers of judgements together to arrive at a final conclusion.

7.4 The first step is to decide on the factors or criteria that are to be used in making the judgement and to prepare a clear summary of what they are and what they mean. The second step is to design record sheets that

14 Topic paper 6 Techniques and criteria for judging capacity and sensitivity

allow the different judgements that need to be made to be recorded clearly, whether they are to be based on desk study or field survey. The time and resources available will influence the level of detail of this record sheet and the level of detail required of the work. Ideally separate records should be made of each component aspect of the final judgement. So for example in the case of a comprehensive capacity study for a particular type of change or develop- ment, a record should be made of the judgements made about: i) the Landscape Character Sensitivity of each landscape type or area to that type of change, which will reflect the sensitivity of individual aspects of landscape character including landform, land cover, enclosure form and pattern, tree cover, settlement form and pattern, and other characteristic elements, and the aesthetic aspects of landscape character, including for example, its scale, complexity, and diversity; ii) the Visual Sensitivity to that type of change, which will reflect, for each landscape type or area; general visibility, influenced by landform and tree and woodland cover, the presence and size of populations of different types, and potential for mitigation of visual impacts, without the mitigation in itself causing unacceptable effects. iii) the Value attached to each landscape, which will reflect:

• national designations based on landscape value; • other judgements about value based either on a 'Quality of Life Assessment', or on consideration of a range of appropriate criteria relating to landscape value.

7.5 These different aspects need to be judged on a simple verbal scale, either of three points - high, medium or low, or of five points - for example very high, high, medium/average, low and very low, or equivalents. A three point scale is much easier to use but a five point scale allows greater differentiation between areas. These scales can easily be translated into shades or colours for graphic display and are well suited to use as layers within a GIS of the type now widely employed in landscape character work.

7.6 The question remains of how layers of information can then be combined to arrive at a final assessment of either sensitivity or capacity, depending on which is required. There are three possible methods: firstly the construc- tion of an overall profile combined into an overall assessment of sensitivity and capacity; secondly the cumulative assessment of sensitivity and capacity by sequential combination of judgements; and thirdly a scoring approach. They are briefly outlined below.

An overall profile 7.7 In the first approach individual assessments are made of the constituent aspects of sensitivity or capacity using a three or five point verbal scale, as outlined above. The amount of detailed assessment that goes into the judgements of each of these factors will depend on the time and resources available and the overall approach taken. These assessments are arranged in a table or matrix to provide a profile of that particular landscape type or area. An overview is then taken of the distribution of the assessments of each aspect and this is used to make an informed judgement about the overall assessment of sensitivity or capacity. Figure 2 gives a hypothetical example:

Figure 2: Building up the overall profile

Landscape Landscape Sensitivity of Sensitivity of Visual LANDSCAPE Value of LANDSCAPE Character Individual Aesthetic Type/Area Sensitivity SENSITIVITY Landscape CAPACITY Sensitivity Elements Aspects Type 1 High Medium Medium High HIGH Low MEDIUM Type 2 Low Medium Low Low LOW Low HIGH Type 3 High High High Medium HIGH High LOW etc

15 Topic paper 6 Techniques and criteria for judging capacity and sensitivity

Cumulative assessment 7.8 In the second approach individual assessments are similarly made but in this case the more detailed lower-level assessments are combined in pairs sequentially until an overall assessment is reached. The number of layers combined in this way depends upon the level of detailed information collected in the survey. This must of course be done for each landscape type or area being assessed. Based on the framework and definitions set out in this paper some simplified and purely illustrative possible combinations (and there are of course others) might be:

• Sensitivity of ecological components + Sensitivity of cultural components = Landscape character sensitivity • General visibility (related to land form and land cover) + Level and significance of populations = Visual sensitivity • Landscape character sensitivity + Visual sensitivity = Overall landscape sensitivity • Presence of designations + Overall assessment of value against criteria = Landscape value • Overall landscape sensitivity + Landscape value = Landscape capacity

7.9 The difficulties with this approach are that it may be somewhat cumbersome and time consuming to apply, especially for large areas, and that decisions must be made about how the individual assessments are to be combined. So, for example, while two HIGHS clearly give a HIGH in the matrix, what about a HIGH and a MEDIUM? Is the highest level used in which case the answer is also HIGH, or is a judgement made on the combinations? There is no single answer but again the emphasis must be on transparency. Figure 3 illustrates this process for two hypothetical combinations. Both could also be shown with a five point scale, as discussed above, to give a more refined assess- ment.

Figure 3(a): Combining HIGH HIGH HIGH Landscape Character High Sensitivity and Visual Sensitivity to give overall MEDIUM MEDIUM HIGH Landscape Sensitivity Medium

Low LOW MEDIUM HIGH Landscape Character Sensitivity Landscape Low Medium High

Visual Sensitivity

Figure 3(b): Combining MEDIUMLOW LOW Landscape Sensitivity High and Landscape Value to give Capacity MEDIUM MEDIUM LOW Medium Landscape Sensitivity Landscape

Low HIGH MEDIUM MEDIUM

Low Medium High

Landscape Value

16 Topic paper 6 Techniques and criteria for judging capacity and sensitivity

Scoring 7.10 In this type of approach the word scales must be combined in a consistent way with appropriate rules applied as to how the combined layers are further classified. This may require that they are converted into numerical equiva- lents for ease of manipulation. Shown graphically, these 'scores' will take the form of different colours or shades, which is generally preferable to presenting the numerical figures themselves. There are certainly examples of work that do take a scoring approach to the layers of information in the assessment, although they may not appear in the final published material.

7.11 While scoring overcomes the difficulty of how individual assessments of each aspect are combined (for example by multiplication within matrices and by adding different matrices) and makes the process transparent, it does lead to a greater emphasis on quantitative aspects of such work. If overemphasised as an end in itself rather than as a means to an end, numerical representation may run the risk of generating adverse reactions because it suggests something other than professional judgement and can suggest a spurious scientific rigour in the process. It was, after all, the overly quantitative nature of landscape evaluation in the 1970s that led to a move away from that approach.

The role of Geographic Information Systems 7.12 Today most sensitivity and capacity studies, whichever approach they take, are likely to rely on Geographic Information Systems (GIS) to manipulate the layers of information. This brings several advantages and notably:

• Consistency of approach, in that appropriate matrices or algorithms can be defined once and then applied consistently throughout a study; • Transparency, in that it is easy to interrogate the base datasets used and also to visualise and communicate intermediate stages of the process if required; • Efficiency and effectiveness in the handling of data, allowing explorations of the information and alternative approaches to combining it which would simply not be achievable in a manual paper based exercise.

8. CURRENT PRACTICE AND ISSUES IN ASSESSING SENSITIVITY AND CAPACITY 8.1 There is a wide range of work, either in progress or completed, which tackles the issues of landscape sensitivity and capacity. Most of it is quite complex and difficult to summarise meaningfully in a short paper like this and there are few if any examples as yet which demonstrate all the principles set out here. Where possible examples have been included in the boxes in the text to illustrate particular aspects of such work, including examples of overall landscape sensitivity studies carried out by local authorities, studies to assess sensitivity to particular types of change or development and capacity studies aimed, for example, at exploring wind turbines or housing, among other types of development. It is hoped that more examples may be available in future and may be included on the Countryside Character Network website (www.ccnetwork.org.uk).

Transparency and Presentation 8.2 It is clear from examination of the strategic studies of overall landscape sensitivity, such as those conducted by Herefordshire,Worcestershire and Staffordshire, that they are enormously detailed and very transparent in describing the approach to analysis and judgements. It is also apparent that they are very detailed and demanding of time and resources, and also quite complex because of the desire to explain each step in the process. However, even experi- enced practitioners who have not been involved in this work may struggle to understand fully the terminology used, the subtleties of the definitions and the judgements that are made at every level of the assessment, as well as the way that the different factors are combined. They may also disagree with some of those definitions - replaceability, for example, is in itself a very complex term open to different interpretations, especially when used in relation to ecolog- ical habitats. A lay audience could well be completely baffled by the complexity of the whole process. So although the arguments are logical, consistent and fully explained this can in itself open up potentially important areas of misunderstanding or debate.

8.3 On the other hand some of the consultants' studies of sensitivity and capacity are often short on transparency and rely on professional judgements, the basis of which is often not clear. It could be argued that there has to be a trade-off between complete transparency in the methods used and the accessibility of the findings to a non-specialist

17 Topic paper 6 Techniques and criteria for judging capacity and sensitivity

audience. Reasoning must always be documented as clearly as possible and the reader of any document should be able to see where and how decisions have been made. Different content and presentation techniques may be needed to tailor the findings of studies for particular audiences. Officers of Worcestershire County Council, for example, intend ultimately to produce the findings of their overall sensitivity analysis in a more accessible form for a wider audience. The complexities in the full explanation of the method are considered necessary to provide the essential degree of transparency and justification but it is recognised that this is only likely to be suited to a specialist audience.

Continuing debates and questions 8.4 Whatever the approach adopted there are likely to be continuing debates on several questions. The main ones that require further exploration as experience grows are: a) Is it reasonable to make assessments of overall landscape sensitivity without considering sensitivity to a specific type of change? In what circumstances will this approach work? b) To what extent should considerations of 'value', as discussed in Section 6 of this paper, be taken into account in landscape capacity studies? This paper argues that they should be, provided that these considerations are clearly thought through and appropriately incorporated in the judgements that are made. Simply relying on designa tions is to be avoided as this is an oversimplification of complex issues but the issue remains of whether there is agreement about the way that value can be defined. At present it seems that this approach to defining capac ity, by combining sensitivity and aspects of value, is reasonably well accepted in Scotland, particularly in recent wind farm capacity studies, but less so in England. c) How can transparency about the approach to making judgements be achieved without the explanations becoming unnecessarily complex and inaccessible? d) To what extent is quantification of assessments of sensitivity or capacity either necessary or desirable, as discussed in Paragraph 7.11? Both quantification and consideration of value suffer from the spectre of the 1970s approaches to landscape evaluation which hangs over them. This needs to be recognised when deciding on and presenting an appropriate approach, in order to avoid unnecessary arguments about its suitability.

Future developments 8.6 This Topic Paper is not intended to be a definitive statement about issues of landscape sensitivity and capacity. Nor is it the intention to recommend or promote a single method. This is a rapidly developing field in which practi- tioners are actively exploring different approaches in different circumstances. The Topic Paper may be amended in future as experience accumulates and the strengths and weaknesses of different approaches become more apparent as they are applied in practice. In the meantime comments on the content of the Topic Paper are invited to assist in this evolutionary process. The discussion forum on the Countryside Character Network website should be used for this purpose if you want to share your views with the wider practitioner community. Alternatively you can send your views by post to the coordinators of the network. Web site address and network contact details are provided in the 'Further Information' section.

18 Topic paper 6 Techniques and criteria for judging capacity and sensitivity

ACKNOWLEDGEMENTS This paper has been written by Carys Swanwick on behalf of the Countryside Agency and Scottish Natural Heritage. Thanks are due to: those who attended the initial workshop and provided further comments, that is Steve Potter of Staffordshire County Council, Chris Bray of Worcestershire County Council, Pat Shears of the Landscape Partnership and Mark Diacono of Diacono Associates; those who provided information for case studies or who commented on earlier drafts, that is John Benson of the Landscape Research Group at the University of Newcastle, Jane Patton of Herefordshire County Council, Rebecca Knight of Land Use Consultants, David Tyldesley of David Tyldesley Associates and Jonathan Porter of Countryscape; and members of the sponsoring agencies for the Landscape Character Assessment Guidance for their comments and input, namely Andy Wharton,Alison Rood and Rick Minter for the Countryside Agency and Richard Ferguson, Nigel Buchan and Caroline Read for Scottish Natural Heritage. The Countryside Agency would like to thank Countryscape for co-ordinating the preparation of this topic paper.

REFERENCES AND FURTHER INFORMATION [1] Countryside Agency (2003) The State of The Countryside 2020. CA 138. Countryside Agency. Cheltenham.

[2] Scottish Natural Heritage (2001) Natural Heritage Trends - Scotland 2001. Scottish Natural Heritage. Battleby, Perth.

[3] Landscape Institute and Institute of Environmental Management and Assessment (2002) Guidelines for Landscape and Visual Impact Assessment. Spon Press, London.

USEFUL WEBSITES Countryside Character Network www.ccnetwork.org.uk

Landscape Character Assessment Guidance (available on line) www.countryside.gov.uk/LivingLandscapes/countryside_character or www.snh.org.uk/strategy/LCA

The full Landscape Character Assessment: Guidance for England and Scotland and related topic papers can be viewed and downloaded from www.countryside.gov.uk/LivingLandscapes/countryside_character and www.snh.org.uk/strategy/LCA

Free copies of the guidance are also available from:

Countryside Agency Publications Scottish Natural Heritage Tel: 0870 1206466 Tel: 0131 446 2400 Fax: 0870 1206467 Fax: 0131 446 2405 Email: [email protected] Email: [email protected]

The map extract used within this publication is reproduced from Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationary Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Countryside Agency, GD272434, 2002.

19 from the DTM. The height of the camera above ground level should also be recorded, but will often be a constant determined by the photographer's height and the need to be able to see through the camera viewfinder.

• Approximate direction of the centre of the panorama as a bearing in degrees. Also, in some situations, particularly on flat or otherwise featureless terrain, it is useful to take accurate bearings to identifiable objects in the scene using a suitable sighting compass. It is sometimes worthwhile also noting the approximate angular separation of frames in a panorama, although it is often convenient to do this by eye, judging the overlap through the viewfinder, or to rely on the indexing on a panoramic tripod.

• Date and time of photography. In conjunction with the position, this will allow the direction of the light to be calculated for photomontage. Also, on a digital camera, there are no frame numbers to note down, so the date and time may well be invaluable in identifying which photographs belong to which locations by referring to the creation time of each image file. (Of course, this will only work if you have set the date and time correctly on the camera.)

• Wind direction is sometimes also useful if there are existing wind turbines in the photograph and it is desired to match their orientation in a photomontage.

E14 Note that other details to do with observation conditions should also be noted, as listed in Tables 8 and 12.

194 Technical Appendix F

Earth Curvature and Refraction of Light

F1 OS co-ordinates are not fully 3-dimensional. The northing and easting define a point on a plane corresponding to the OS transverse Mercator map projection and the altitude above OS datum is measured above an equipotential surface passing through the OS datum point at Newlyn. In reality, the earth is of course round, so a correction has to be made in order to position geographical features correctly in three dimensions for ZTV calculation and for visualisation.

F2 If it wasn't for the presence of the Earth's atmosphere, a simple allowance for curvature would be sufficient. The formula for this can be worked out quite easily from Pythagoras' theorem.

F3 Consider an observer at a point A looking towards point B at a distance c. The difference h between the vertical position of B measured along a true horizontal and along the surface of the earth is the height correction required. Points A and B and the centre of the earth (or radius r) form a right-angled triangle. Applying Pythagoras:

+=+ hrrc )( 222 Figure F1: Calculating the height 2 ++=+ hrhrrc 2222 correction due to earth curvature 2 += hrhc 22 += )(2 hhr += )(2 hhrc

h is very small in comparison with r, so the formula can be approximated with:

= 2rhc

195 Rearranging for h, we get:

2 = crh 2 = crh 2 c 2 h = 2r r, c and h must all be in the same units, either metres or kilometres.

F4 Note that although the local vertical at B is very different from the local vertical at A in the diagram, in reality these points are very close together compared to the size of the earth and assuming that the height h correction is vertical does not introduce significant errors. (The horizontal correction increases with the square of distance, as in the same way that the vertical correction does, but at 45km from the viewpoint, it is still only about 1m.).

F5 In practice, rays of light representing sightlines over long distances are also curved downwards as a result of refraction of light through the atmosphere, allowing one to see slightly beyond the expected horizon. (The atmosphere reduces the vertical correction due to curvature alone by about 15%.) The standard formula used in surveying work is modified from the one Figure F2: Calculating the height derived above as follows: correction due to earth curvature and refraction through the atmosphere 2 − kc )21( h = 2r

Where:

h is the height correction in metres c is the distance to the object in metres k is the refraction coefficient r is the radius of the Earth in metres

F6 The parameter k is not constant but varies with temperature and barometric pressure (and therefore also with altitude). For precise geodetic surveying work

196 both these quantities would have to be measured at both ends of a line of sight. Visualisation and visibility analysis do not require such precision, therefore a representative value may be used. 0.075 is a reasonable average for inland upland observations, but very slightly different values may be found quoted in surveying or navigation textbooks. (k is a numerical coefficient and therefore has no units.)

F7 Taking k = 0.075 and r = 6,367,000m, the following example values are obtained:

Table 19: Height corrections for earth curvature and refraction Distance c Vertical correction for Earth curvature and atmospheric refraction h

5 km 1.7m 10 km 6.7m 15 km 15.0m 20 km 26.7m 25 km 41.7m 30 km 60.1m 35 km 81.8 m 40 km 106.8 m 45 km 135.2 m 50 km 166.9 m 55 km 201.9 m 60 km 240.3 m

197 198