METHODOLOGY FOR IMPACT ASSESSMENT ON HERITAGE ASSETS The determination of impacts on heritage assets follows the standard procedures applied to all Environmental Impact Assessment. This entails the identification of the receptor an assessment of the receptor s importance the identification of the magnitude of impact the identification of the significance of the impact IDENTIFICATION OF THE RECEPTOR Heritage assets comprise designated and non-designated assets. Baseline studies to establish the presence heritage assets are undertaken following the methodologies outlined in the main text. ASSESSMENT OF THE RECEPTOR S IMPORTANCE Significance lies in the value of a heritage asset to this and future generations because of its heritage interest, which may be archaeological, architectural, artistic or historic (DCLG 2010, 14). Archaeological interest includes an interest in carrying out an expert investigation at some point in the future into the evidence a heritage asset may hold of past human activity (ibid, 13) and may apply to standing buildings or structures as well as buried remains. Known and potential heritage assets within the site and its vicinity have been identified from national and local designations, HER data and expert opinion. The determination of the significance of these assets is based on statutory designation and/or professional judgement against four values (EH 2008): Evidential value: the potential of the physical remains to yield evidence of past human activity. This might take into account date; rarity; state of preservation; diversity/complexity; contribution to published priorities; supporting documentation; collective value and comparative potential. Aesthetic value: this derives from the ways in which people draw sensory and intellectual stimulation from the heritage asset, taking into account what other people have said or written; Historical value: the ways in which past people, events and aspects of life can be connected through heritage asset to the present, such a connection often being illustrative or associative; Communal value: this derives from the meanings of a heritage asset for the people who know about it, or for whom it figures in their collective experience or memory; communal values are closely bound up with historical, particularly associative, and aesthetic values, along with and educational, social or economic values. Designated Heritage Assets In respect of designated heritage assets the PPS5 practice guide states that their importance or significance is based on these components as follows:
Table 1: of designated heritage assets Heritage Asset Archaeological Historic Special Architectural/artistic Listed Buildings Scheduled Monuments National National National Parks and Gardens Battlefields Conservation Areas Wrecks Non-designated Heritage Assets Non designated heritage assets also qualify of interest in one or more of these categories (archaeological, historic and or architectural/artistic). However they will not be classified as of national or special (national or importance. It should be noted, however, that research undertaken as part of the assessment presented in the main text of this report may indicate that a heritage asset, whilst not currently designated may warrant designation. Importance/Significance The Design Manual for Roads and Bridges (Volume II, Section 3, Part 2) (2007) concurs with the above classifications for the importance/significance of designated heritage assets. However, it also provides guidance on how non-designated heritage assets can be classified, see table 1 below. Where heritage designations fall within two categories of importance/significance, however, or where heritage assets are not designated the following documents/guidelines are used in conjunction with the table below to identify their importance/significance: Conservation Principles: Policies and Guidance (English Heritage 2008) Scheduling criteria Criteria for Listing and Regional Archaeological Research Frameworks
Table 2: Establishing the importance/significance of the heritage asset Importance/ Significance Heritage Asset Archaeological Remains Historic Buildings Historic Landscapes Very High (international)* High (National)* Medium (Regional)* Low (Local)* World Heritage Sites Other sites of acknowledged international importance Sites that can contribute significantly to acknowledged international research objectives Scheduled Ancient Monuments Undesignated sites of schedulable quality and importance Sites that can contribute significantly to acknowledged international research objectives undesignated assets that contribute to regional research objectives undesignated assets of local importance Assets compromised by poor preservation and/or poor World Heritage Sites Other buildings of recognized international importance Scheduled Ancient Monuments with standing remains Grade I and all Grade II* Listed Buildings (Scotland Category A) Other listed buildings that can be shown to have exceptional qualities in their fabric or historical associations not adequately reflected in their listing grade Conservation Areas containing very important buildings Undesignated structures of clear national importance Grade II Listed Buildings (Scotland Category B) Historic (unlisted) buildings that can be shown to have exceptional qualities in their fabric or historical associations Conservation Areas containing buildings that contribute significantly to its historic character Historic townscape or built up areas with important historic integrity in their buildings, or built settings (e.g. including street furniture and other structures) Locally listed buildings (Scotland Category C) Historic (unlisted) buildings of modest quality in their fabric World Heritage Sites Historic landscapes of international value, whether designated or not Extremely well preserved historic landscapes with exceptional coherence, time depth, or other critical factor(s) Designated historic landscapes of outstanding interest Undesignated landscapes of outstanding interest Undesignated landscapes of high quality and importance, and of demonstrable national value Well preserved historic landscapes, exhibiting considerable coherence, time depth or other critical factor(s) Designated special historic landscapes Undesignated historic landscapes that would justify special historic landscape designation, landscapes of regional value Averagely well preserved historic landscapes with reasonable coherence, time depth or other critical factor(s) Robust undesignated historic landscapes Historic landscapes with importance to local
Negligible* Unknown* survival of contextual associations Assets of limited value, but with potential to contribute to local research objectives Assets with very little or no surviving archaeological interest The importance of the resource has not been ascertained or historical association Historic townscape or built up areas of limited historic integrity in their buildings, or built settings (e.g. including street furniture and other structures) Buildings of no architectural or historical note Buildings with some hidden (i.e. inaccessible) potential for historic significance Adapted from the Design Manual for Roads and Bridges, Volume II, Section 3, Part 2 (2007) interest groups Historic landscapes whose value is limited by poor preservation and/or poor survival of contextual associations Landscapes with little or no significant historic interest - IDENTIFICATION OF THE MAGNITUDE OF IMPACT Heritage assets are susceptible to numerous forms of development and non development impacts both during the construction process and as a consequence of the operational life of the proposed development. These can be either direct (physical) impacts or indirect (non-physical) impacts. Some but not all of potential impacts are listed below: Direct impacts Direct impacts on heritage assets can include one or more of the following. Note this is not an exhaustive list. Excavations for demolition, drainage, foundations, borrow pits and decontamination Ground investigations (trial pits and boreholes) Topsoil removal Piling Removal of trees and vegetation Compaction Landscape planting and fencing Earth mounding Demolition of buildings Repairs to and alteration of buildings Indirect Impacts Indirect impacts on heritage assets are those that: Alter the setting of statutorily designated heritage assets Contaminate buried remains Dry out or waterlog buried remains Disturb buildings or buried remains through vibration Cause damage to structures through pollution The magnitude of an impact is the amount of physical alteration or removal which can be expected. The magnitude of impacts through development upon heritage features as stated by the Design Manual for Roads and Bridges (Volume II, Section 3, Part 2) (2007) can be categorized as follows:
Major Moderate Minor Negligible No Change These are presented in Table 3 below. The magnitude of impact is measured from the condition that would prevail in a do nothing scenario and it is assessed without regard to the importance of the receptor (DMRB 2007). The worst magnitude of impact would be complete physical removal of the receptor. In some instances it is possible to discuss percentage loss when establishing the magnitude of impact. However complex receptors will require a much more sophisticated approach (DMRB 2007). Currently there are no generally recognized guidelines for the assessment of setting impacts. However, the following points, quoted by Historic Scotland in official correspondence, are considered by Wardell Armstrong to be relevant UK wide when establishing the magnitude of a setting impact: The relative weight which statute and policy attach to the asset in question Importance of topographic location for understanding the function of the site and the choice of its location Relevance of current or past land use Group setting and relationship to, and inter-visibility with, other sites in the landscape Scale and extent both of the site and of the development Views both to and from the site, including cases where the development and the site may not be inter-visible but are both caught in important views Distance between the site and the development Presence of intervening buildings/vegetation/topography between the site and the development Table 3: Establishing the magnitude of impact Magnitude of Impact Major Description of impact Archaeological Remains Historic Building Historic Landscapes Change to most or all key archaeological materials, such that the resource is totally altered Comprehensive changes to setting Change to key historic building elements, such that the resource is totally altered Comprehensive changes to setting Total change to historic Changes to most or all key historic landscape elements, parcels or components Extreme visual effects Gross change to noise or change to sound quality Fundamental changes to use or access Moderate Changes to many key Changes to many key historic Moderate change to historic
archaeological materials, such that the resource is clearly modified Considerable changes to setting that affect the character of an asset Minor Changes to key archaeological materials, such that the asset is slightly altered Slight changes to setting Negligible Very minor changes to archaeological materials, or setting building elements, such that the resource is significantly modified Changes to the setting of an historic building, such that it is significantly modified Change to key historic building elements, such that the asset is slightly different Change to the setting of an historic building, such that it is noticeably changed Slight changes to historic buildings elements or setting that hardly affect it Changes to many key historic landscape elements, parcels or components Visual change to many key aspects of the historic landscape Noticeable differences in noise or sound quality Considerable changes to use or access Limited change to historic Changes to few key historic landscape elements, parcels or components Slight visual changes to few key aspects of the historic landscape Limited changes to noise levels or sound quality Slight changes to use or access Very small change to historic Very minor changes to key historic landscape elements, parcels or components Virtually unchanged visual effects Very slight changes to noise levels or sound quality Very slight changes to use or access No change No Change No change to fabric or setting No changes to elements, parcels or components No visual or audible changes No changes in use or access Design Manual for Roads and Bridges, Volume II, Section 3, Part 2 (2007)
IDENTIFICATION OF THE SIGNIFICANCE OF IMPACT The significance of an impact is devised by cross referencing the importance of the receptor with the magnitude of the impact, see Table 4. Table 4: Establishing the significance of negative impact Importance of receptor Magnitude of Very High High Medium Low Negligible impact No change Neutral Neutral Neutral Neutral Neutral Negligible Slight Slight Neutral/ Neutral/Slight Neutral Slight Minor Moderate/Large Moderate/ Slight Neutral/Slight Neutral/Slight Slight Moderate Large/ Moderate/ Moderate Slight Neutral/Slight Very Large Large Major Very Large Large/ Moderate/L Slight/ Slight Very Large arge Moderate Design Manual for Roads and Bridges, Volume II, Section 3, Part 2 (2007)