LANDSCAPE AND VISUAL IMPACT ASSESSMENT

WHY LANDSCAPE AND VISUAL IMPACT ASSESSMENT?

• Article 3 of the 1997 Directive states:“The environmental impact assessment shall

identify, describe and assess....the direct and indirect effects of a project on:

Human beings, fauna and floraSoil, water, air, climate and the landscapeMaterial assets and the cultural heritageThe interaction between the factors...”

ASSESSMENT OF EFFECTS

• It is current practice to assess tworelated effects:– On the landscape (landscape impact)– On people (visual impact)

ASSESSMENT OF EFFECTS• The aim is to

– Identify systematically the likely effects of thedevelopment

– Indicate measures to avoid, reduce, remedy orcompensate for those effects (mitigationmeasures)

– Estimate the magnitude of the effects– Assess the nature and significance of these

effects in a logical and well-reasoned fashion.

SOURCES OF EFFECTS• Changes in land use eg arising from mineral

extraction, afforestation, recreation or landdrainage.

• Development of buildings and structures suchas power stations, industrial estates, roadsand housing.

• Changes in land management such asintensification of agriculture.

• Changes in production processes and emissions such as those from chemicalplants.

NATURE OF EFFECTS

• Effects can be:– Negative (adverse) or positive(beneficial)– Direct or indirect, secondary or cumulative– Permanent or temporary (short, medium or

long-term)– Arise at different scales (local, regional or

national)

EXTENT OF EFFECTS• The geographical extent of the potential

effects has to be established.• This can be derived from the Zone of

Theoretical Visibility (ZTV) of a set radiusfrom the development – often 30-35km.

• The ZTV is derived from landform, so screening may occur. Additional screeningfrom trees and buildings is established fromsite visits.

The methodology includes the following tasks:

1. Establishment of the extent of the study area

2. Description of the setting and context of the development including land use and local development and landscape policies

3. Identification of the landscape resources likely to be affected occurring within the study area and their sensitivity

4. Identification of the visual resources likely to be affected occurring within the study area and their sensitivity

5. Assessment of the magnitude and significance of effect on the landscape resources during construction, during operation and during decommissioning of the development.

6. Assessment of the magnitude and significance of effect on the visual resources during construction, during operation and during decommissioning of the development.

7. Identification of mitigation measures to reduce any assessed effects

8. Cumulative impact assessment with other developments in the study area or overlapping with it.

LANDSCAPE EFFECTS

• Landscape impact assessmentsdescribes the nature and scale of thelikely impact on landscape resources:– Landscape character– Special or highly valued landscapes– Protected or designated landscapes

SENSITIVITY OF THE LANDSCAPE RESOURCE

The degree to which a landscape canaccommodate change will vary according to:– Existing land use– Pattern and scale of the landscape– Visual enclosure or openness– Scope for mitigation in character with the

landscape– Value placed on the landscape

SENSITIVITY OF THE LANDSCAPE RESOURCE

Sensitivity can be calculated according toa number of criteria and ranked as– high, – medium, – low or– negligible

sensitivity of the landscape resourcecriteria high medium low negligiblelandscape designations

landscape designated for its national landscape value

landscape designated for regional or county-wide landscape value

landscape designated for local value or valued locally as for example as an important open space

no designations present

landscape quality

distinctive landscape with strong sense of place and integrity

distinctive landscape with strong sense of place but with some detractors

landscape with relatively ordinary characteristics, some detractors

featureless, spoiled or mundane landscape with weak sense of place

cultural heritage interests

contains features or sites of national importance

contains sites of regional importance

contains some sites of local importance

few sites or features of importance

landscape characteristics such as pattern, scale, form, tranquillity, wildness

landscape with characteristics that are highly sensitive and highly affected by development

characteristics moderately sensitive to change from development

characteristics not greatly affected by development

characteristics relatively unaffected by development

Proportion of resource in ZTV

Large proportion affected; site lies in it

Moderate proportion affected

Small proportion affected

Very small proportion affected

Distance from the site

Close to the site; site lies in it

Within 15km Beyond 15km Beyond 15km

MAGNITUDE OF LANDSCAPE EFFECT

This depends on the scale of the developmentand its effect on factors such as wildness oron landscape character:– Large– Medium– Small– Negligible

Class Name DescriptionLarge Dominant very extensive, highly noticeable change,

affecting most key characteristics and dominating the experience of the landscapeintroduction of highly incongruous elements changes over a long period of time

Medium Conspicuous noticeable change to a significant proportion of the landscape, affecting some key characteristics and the experience of the landscapedevelopment with some uncharacteristic elements changes that will affect the landscape over the medium term

Small Apparent minor change, affecting some characteristics and the experience of the landscape to an extentintroduction of elements that are not uncharacteristicchanges that are of short duration

Negligible Inconspicuous little perceptible changeintroduction of elements that are not uncharacteristicchanges that are of very short duration

SIGNIFICANCE OF LANDSCAPE EFFECT

This can be adverse to different degrees:– Severe– Major– Moderate– Minor– Negligible

Significance DefinitionSevere adverse The proposed project would result in effects that:

are at complete variance with the landform, scale and pattern of the landscape;would permanently degrade, diminish or destroy the integrity of valued landscape features, elements and/or their setting; would cause a very high quality landscape to be permanently changed and its quality diminished.

Major adverse The proposed scheme would result in effects that:cannot be fully mitigated and may cumulatively amount to a severe adverse effect;are at a considerable variance to the landscape degrading the integrity of the landscape;will be substantially damaging to a high quality landscape.

Moderate adverse The proposed scheme would:be out of scale with the landscape or at odds with the local pattern and landform;will leave an adverse impact on a landscape of recognised quality;

Minor adverse The proposed scheme would:not quite fit into the landform and scale of the landscape;affect an area of recognised landscape character

Negligible The proposed scheme would:complement the scale, landform and pattern of the landscape; maintain existing landscape quality

landscape sensitivity

magnitude of change

high medium low negligible

large severe major moderate moderate/minor

medium major major/moderate moderate/minor minor

small moderate moderate/minor minor minor/negligible

negligible moderate/minor minor minor/negligible none

VISUAL EFFECTS• These are effects on viewers (visual

receptors) and are usually assessed for a number of viewpoints.

• Viewpoints need to be assessed forsensitivity

• Visualisations of the proposed developmentfrom the viewpoints are used for theassessment.

VISUAL EFFECTS• Viewpoints are selected from the places

within the ZTV that are typical locationsfor viewers to be present:– Roads– Houses– Viewpoints– Tourist and recreational facilities

VISUAL EFFECTS

• Photographs are taken from eachviewpoint (panoramic, 90 degreeviewcone, 50mm lens, good light, possibly winter and summer)

• GPS reading used to locate eachviewpoint accurately.

VISUAL EFFECTS• Each viewpoint is assessed for

sensitivity– Visibility– Numbers of viewers– Nature of the viewing experience

• This is assessed as high, medium orlow

VISUAL EFFECTS

• Assessment is made of the magnitudeof the visual effect and the significanceof the visual effect.

• Computer generated wireframes and/orphotomontages are used to simulate theappearance of the development.

MAGNITUDE OF VISUAL EFFECTS

• A scale of magnitude is used:– High– Medium– Small– Negligible

Magnitude Description Description – appearance in field of visionlarge dominant major change to the view, striking, sharp,

unmistakeable, easily seencreation/removal of dominant visual focushighly incongruous elements or pattern introducedhigh proportion of the view affectedlong term change

medium conspicuous noticeable change to the view, distinct, clearly visible, well definedcreation or removal of a visual focussome elements of the development fit underlying visual compositionsignificant proportion of the view affected view changed over the medium term

small apparent minor change to the view but still evidentlittle change to focus of the viewfits intrinsic visual compositionsmall proportion of the view affectedshort term change to the view

negligible inconspicuous no real change to perception of the viewweak, not legible, near limit of acuity of human eye

Tend to reduce apparent magnitude Tend to increase apparent magnitude

static movement

backgrounding skylining

cloudy sky clear sky

low visibility (colour) high visibility (colour)

absence of visual clues visual clues

mobile receptor static receptor

object not focal point object as focal point

complex scene simple scene

low contrast (form or colour) high contrast (form or colour)

screening lack of screening

high elevation of viewpoint low elevation

SIGNIFICANCE OF VISUAL EFFECTS

• A scale of significance is used:– Major adverse– Moderate adverse– Minor adverse– No change

Degree of impact

Description

Major adverse impact

Where the scheme would cause a significant deterioration in the existing view

Moderate adverse impact

Where the scheme would cause a noticeable deterioration in the existing view

Minor adverse impact

Where the scheme would cause a barely perceptible deterioration in the existing view

No change No discernable deterioration or improvement in the existing view

visual sensitivity

magnitude of change high medium low

large major major/moderate moderate

medium major/moderate moderate moderate/minor

small moderate moderate/minor minor

negligible moderate/minor minor minor/negligible

LANDSCAPE AND VISUAL IMPACT ASSESSMENTWHY LANDSCAPE AND VISUAL IMPACT ASSESSMENT?ASSESSMENT OF EFFECTSASSESSMENT OF EFFECTSSOURCES OF EFFECTSNATURE OF EFFECTSEXTENT OF EFFECTSLANDSCAPE EFFECTSSENSITIVITY OF THE LANDSCAPE RESOURCESENSITIVITY OF THE LANDSCAPE RESOURCEMAGNITUDE OF LANDSCAPE EFFECTSIGNIFICANCE OF LANDSCAPE EFFECTVISUAL EFFECTSVISUAL EFFECTSVISUAL EFFECTSVISUAL EFFECTSVISUAL EFFECTSMAGNITUDE OF VISUAL EFFECTSSIGNIFICANCE OF VISUAL EFFECTS