5 Scope of the Assessment and Significance of Effects 5.1 Scoping for the Stage 3 Assessment 5.2 Summary of Scope 5.3 Format for the Environmental Assessments 5.4 Forms of Impact 5.5 Impact Ratings and Significance of Residual Effects

5 Scope of the Assessment and Significance of Effects

5.0 Scope of the Assessment

5.0.1 The overall framework adopted for the assessment of the potentially significant impacts for the Proposed Scheme has been that detailed in Volume 11 of the DMRB.

5.0.2 The DMRB identifies three stages of environmental assessment as a scheme is planned and taken through to the specimen design for the Proposed Scheme.

5.0.3 Stage1 establishes key environmental constraints and opportunities as a basis for informing an engineering, environmental, operational and economic assessment and leading to the identification of initial alignment/corridor options. A Stage 1 assessment was undertaken for the project in 19994.

5.0.4 Stage 2 involves more detailed consideration of environmental interests and opportunities as part of an engineering, environmental, operational and economic evaluation of the options leading to a recommendation for a preferred scheme. A Stage 2 assessment was undertaken for the project in 20035, the environmental considerations of which are presented in Chapter 3.

5.0.5 Stage 3 involves the detailed assessment of the adopted preferred scheme. This enables appropriate design modifications to be made in light of the detailed assessment and subsequent detailed evaluation of the nature and significance of the environmental effects which it is predicted would be associated with the resultant Proposed Scheme. It is the findings of this detailed assessment that are reported in the project ES.

5.0.6 Throughout the three stages, a process of scoping ensures that potentially significant environmental impacts are addressed. These may be added to or omitted in light of emerging information or preliminary assessment findings as initial planning and design for the project proceeds.

5.0.7 Volume 11 of the DMRB provides guidance on the environmental interests under which a road scheme of the type proposed may result in specific impacts. These comprise:

  • Air Quality
  • Cultural Heritage
  • Disruption Due to Construction
  • Ecology and Nature Conservation
  • Landscape Effects
  • Land Use
  • Traffic Noise and Vibration
  • Pedestrians, Cyclists, Equestrians and Community Effects
  • Vehicle Travellers
  • Road Drainage and the Water Environment
  • Geology and Soils
  • Impact of Road Schemes on Policies and Plans

5.1 Scoping for the Stage 3 Assessment

5.1.1 The scoping for the Stage 3 assessment for the Proposed Scheme has been based on consideration of potential impacts under the broad environmental headings defined above. It has been further informed by the following tasks:

a review of the Stage 1 and stage 2 reports for the project to determine the initially identified environmental interests and constraints;

a review of development plan documentation and environmental policies and plans specific to the local and wider area;

consultation with statutory bodies and other environmental groups and interests with knowledge of the environment associated with the Proposed Scheme corridor and other relevant neighbouring areas; and

site appraisal to establish any recent changes in the status or composition of environmental components and interests.

5.1.2 The findings of the Stage 3 scoping are outlined below under the Volume 11 headings.

Air Quality/Traffic Noise and Vibration

5.1.3 The consideration of potential impacts resultant from changes in local air quality and noise levels relates to determining how traffic flows will vary in relation to the displacement of the A75 up to 66.5 m to the south. These factors relate to various threshold screening criteria contained within the DMRB that are used to scope the need for assessment.

Traffic Noise and Vibration

5.1.4 In the period following a change in traffic flow, namely the opening year of a scheme, people may benefit or disbenefit when the noise changes are as small as 1dB(A); equivalent to an increase in traffic flow of 25% or a decrease in traffic flow of at least 20%. In this regard, the B725 north of the A75 just meets the latter of these criteria in the Opening Year. From the Average Annual Weekday Traffic contained in Appendix C, analysis of the difference in traffic flows between the 2010 Do Nothing figure of 668 vehicles and the Do Something figure of 537 is a reduction of 131 vehicles or 20%.

5.1.5 Consideration of potential noise impacts within DMRB requires the application of the Calculation of Road Traffic Noise (CRTN) guidance. This guidance document however states that calculations of noise levels for roads with less than 1000 vehicles per day (taken over an 18 hour period) are unreliable. Consequently, as the predicted flows on the B725 peak at 680 vehicles (2025 Do Something scenario), there is not considered to be a robust technical justification for undertaking such calculations. In addition, given the proximity of the A75 and the relative contribution to noise levels from this dominant source at sensitive receptor locations, it is considered unlikely that the actual change in vehicle numbers over the relative percentage change, modelled as -131 vehicles, will give rise to an effective 1dB(A) change in noise levels. It is for these reasons that this issue has been scoped out.

Air Quality

5.1.6 The DMRB guidance does not expressly define screening criteria relating to air quality in favour of ‘identifying areas where it is likely that the air quality will be improved or will deteriorate as a result of a change to traffic flows and speed or as a result of congestion or queuing time’. However, criteria contained within the Department for Transport (DfT) Transport Analysis Guidance (TAG) and its Scottish equivalent ScotTAG, have been widely adopted by the practicing air quality community. These state that ‘due to the uncertainty in traffic forecasting and the size of traffic flow change needed to affect air quality, options which change traffic flows by less than 10% can usually be scoped out, unless the road is a motorway (due to the high traffic flows) or there are particular sensitivities (e.g. traffic congestion, change to the speed limit or the presence of an Air Quality Management Area)’.

5.1.7 Traffic flows on all roads considered in this assessment, with the exception of the B725 south of the A752 and the U81a north of the A75, are affected by the Proposed Scheme by less than 10% in the Opening Year (2010) (see Appendix C) . With the Proposed Scheme in place, the flows these roads are low (less than 350 and 150 vehicles per day respectively). Guidance provided in both the Government’s Local Air Quality Management Technical Guidance 2003 (LAQM.TG(03)) and the National Society for Clean Air (NSCA (2006) 6, states that ‘roads below 10,000 AADT normally have a minimal impact on local air quality’, and are also not required to be considered by Local Authorities when conducting air quality assessments as part of the LAQM Review and Assessment Process.  As total AADT flows on the two roads in question is significantly below this screening threshold, it is concluded that, despite receiving a change in flow of greater than 10%, the potential impact of such changes on the local air quality at sensitive receptors will be minimal and therefore considered not significant.  Air Quality has therefore been scoped-out as there will be an indiscernible change from the current situation once the scheme is operational.

5.1.8 Noise and air issues with regards to construction-related activity are considered further in Chapter 15; Disruption Due to Construction

Cultural Heritage

5.1.9 The Stage 1 and 2 assessments identified a number of known archaeological sites and features that contribute to the historic built environment in the vicinity of the Proposed Scheme. Braehill Fort and Enclosure, is located some 150 m to the north of the existing road. The north western corner of the Kinmount House Designed Landscape is located some 600 m east of the eastern end of the Proposed Scheme. There is also an Archaeological Consultation Zone centred on Carrutherstown. Taking these findings into account and in light of consultations with Historic Scotland, it was concluded that a further assessment should be undertaken during the Stage 3 assessment of the Proposed Scheme.

Ecology and Nature Conservation

5.1.10 The Stage 1 and 2 assessments confirmed that there are no designated nature conservation sites associated with the Proposed Scheme corridor. Consultation with Scottish Natural Heritage (SNH) and Dumfries and Galloway Council (D&GC) and preliminary site visits established that the scheme area is dominated by habitats of negligible ecological value with some areas of woodland of potentially local value. Preliminary studies during the selection of a preferred route established evidence of use of the area by otter and badger and indicated a potential for bat and water vole activity. Some local areas were also identified as being of potential interest for invertebrates. Potential breeding bird activity associated with woodland, scrub and hedgerows within the area was also recognised.

5.1.11 In light of these findings and taking into account consultations with SNH and D&GC, it was concluded that further assessment should be undertaken during the Stage 3 assessment of the Proposed Scheme.

Landscape Effects (including Visual Impacts)

5.1.12 The landscape associated with the Proposed Scheme corridor broadly comprises pastoral agricultural land and occasional arable fields, which have established a man-made and managed landscape.

5.1.13 The Proposed Scheme would involve the retention of much of the existing trunk road for use by local traffic and the establishment of a new alignment to the south of the existing section of trunk road and the grade separation and realignment of the existing U81a junction.

5.1.14 As a result it would serve to extend the influence of roads and their traffic within the local landscape between Carrutherstown and Upper Mains. It would also result in a change in the relationship for a small number of visual receptors associated with the corridor and the traffic which would be transferred from the existing alignment to the proposed more southerly alignment for the trunk road.

5.1.15 It was concluded that there would be the potential for significant impact on local landscape character and visual receptors and that a detailed assessment should be undertaken during the Stage 3 assessment of the Proposed Scheme.

Land Use

5.1.16 The retention of the existing road and introduction of a new road to the south would result in loss, and severance of, land for a number of agricultural holdings whilst the closure of most of the existing private junctions onto the trunk road would result in diversion of access for a number of properties and holdings.

5.1.17 It was concluded that there would be the potential for significant impact on existing holdings and that further assessment should be undertaken during the Stage 3 assessment of the Proposed Scheme.

Pedestrians, Cyclists, Equestrians and Community Effects

5.1.18 It was established during the Stage 1 and 2 assessments that there are no designated rights of way within the local area. It was, however recognised that the closure of existing access on to the proposed new section of trunk road and retention of the existing road for local use would impact on Non-Motorised Users (NMU) and access between local communities within the local area.

5.1.19 It was concluded that there would be the potential for significant impact on NMU and further assessment should be undertaken during the Stage 3 assessment of the Proposed Scheme.

Vehicle Travellers (View from the Road and Driver Stress)

5.1.20 The Proposed Scheme aims to provide safer overtaking opportunities for users along the A75 and to reduce conflicts between strategic and local traffic; an existing and significant contributor to driver stress.

5.1.21 The alignment offline would also result in a change in the view from the road where the balance between cutting and embankment, introduced as part of the Proposed Scheme, would modify the experience of the local landscape for users of the trunk road.

5.1.22 It was concluded that there would be the potential for significant impact on Vehicle Travellers and that further assessment should be undertaken during the Stage 3 assessment of the Proposed Scheme.

Road Drainage and the Water Environment

5.1.23 The Proposed Scheme requires the creation of four new culverts and increases the total surface run-off locally. It was concluded therefore that there would be a potential impact on surface water quality associated with the four local watercourses and that further assessment should be undertaken during the Stage 3 assessment.

Geology and Soils

5.1.24 The Stage 1 and 2 assessments did not discount the potential impact on geological interests or soils. However, as the detailed assessment progressed, it became evident that no such potential existed.

5.1.25 The site’s geology and soils are however an important data source in defining other environmental parameters such as the surface and groundwater quality and regime. A chapter that reports the baseline conditions has been accordingly reported in the ES.

Policies and Plans

5.1.26 The scoping concluded that an appraisal of the implications of the Proposed Scheme for policies and plans of relevance in the national, regional and local context should be undertaken.

Disruption Due to Construction

5.1.27 There would be the potential for temporary impacts associated with noise and dust generated during the anticipated 52-week construction period. There is also the likelihood of disruption to existing users of the trunk road and temporary local access restrictions to farmsteads and Carrutherstown as the tie-in sections of the new alignment are merged with the existing A75 to the west and east of the upgraded section of the trunk road7. There would also be the potential for pollution of watercourses as earth works progress and construction plant operates in close proximity to the existing watercourses.

5.1.28 It was concluded that whist many of these would be relatively short-term impacts, they would potentially constitute some of the more significant impacts associated with the Proposed Scheme and that further assessment should be undertaken during the Stage 3 assessment of the Proposed Scheme.

5.2 Summary of Scope

5.2.1 In summary, the scoping of potential issues concluded that the Stage 3 EIA should address the following environmental topics.

  • Cultural Heritage
  • Disruption Due to Construction
  • Ecology and Nature Conservation
  • Landscape Effects
  • Land Use
  • Pedestrians, Cyclists, Equestrians and Community Effects
  • Vehicle Travellers
  • Road Drainage and the Water Environment
  • Geology and Soils
  • Impact of Road Schemes on Policies and Plans

5.3 Format for the Environmental Assessments

5.3.1 A standardised format has been adopted for each of the chapters reporting the findings of the various assessments.

  • Introduction.
  • Scope of the Assessment – an outline of the key issues addressed during the assessment.
  • Statutory and Planning Context – a summary of the key statutes, regulations and policy documents of relevance to the environmental topic area and the potential issues identified.
  • Method of Assessment – a description of the baseline data sources, evaluation criteria and significance criteria adopted during the assessment.
  • Baseline Conditions – a description of the nature and status of the existing environment.
  • Predicted Impacts – a description and quantification of the predicted impacts based on the evaluation criteria defined in the method of assessment.
  • Mitigation – a description of the proposed mitigation measures with the objective of avoiding, reducing or compensating for the identified impacts.
  • Residual Effects – a description of the residual effects and their significance taking into account the proposed mitigation measures which have been incorporated as part of the Proposed Scheme.

5.4 Forms of Impact

5.4.1 Predicted impacts may be positive or negative, direct or indirect, short-term, medium-term, long-term or permanent.

5.4.2 An example of a positive impact would be the introduction of a system for intercepting pollutants in surface water run-off prior to discharge to a watercourse where no existing system is available. An example of a negative impact would be the loss of an archaeological asset or impacts on the local flora/fauna.

5.4.3 An example of a direct impact would be loss of woodland to accommodate the proposed alignment. An example of an indirect impact would be loss of sensitive aquatic habitat at distance downstream from the Proposed Scheme as a result of pollution associated with discharge of contaminated run-off.

5.4.4 An example of a short-term impact could be dust deposition associated with construction of the Proposed Scheme. Moderate-term impact could be represented by sedimentation of a local watercourse during construction that would take some months to recover. Long-term impacts could relate to the re-establishment of mature woodland as a key landscape component where a proposal requires the removal of such a resource. A permanent impact could be represented by the loss of a sensitive area of habitat which could not be replicated.

5.5 Impact Ratings and Significance of Residual Effects

Impact Ratings

5.5.1 The order of predicted impacts has been described in accordance with criteria that have been defined in the method of assessment for each environmental topic.

5.5.2 In some instances the criteria relate to quantitative thresholds prescribed by regulation or national targets (e.g. local water quality). In other instances they rely on the sensitivity of the affected receptor and the magnitude of the predicted impact and are represented by descriptive scales (e.g. – minor, moderate or substantial impact on local landscape character).

5.5.3 Where considered appropriate, a rating reflecting a point close to the upper or lower end of threshold in a descriptive scale is represented by a combined rating. For instance, a moderate/low rating for landscape character would indicate a moderate impact at the lower end of that threshold. Low/moderate would represent a low impact at the higher end of that threshold.

Determining the Significance of Residual Effects

5.5.4 The following factors have been considered during the determination of the significance of the predicted residual effects:

  • the relative importance of the environmental resource in question (i.e. national, regional, or local importance);
  • whether environmental quality will be impaired or enhanced in relation to standards and guidelines (i.e. noise, air, water quality);
  • whether the environmental impact will be direct (such as land-take) or indirect (such as polluted run-off entering watercourses);
  • the scale of the change (e.g. the area of land, number of people affected) and the degree of change from existing conditions;
  • the scale of change resulting from cumulative impacts;
  • whether the effect is permanent or temporary and, if the latter, its duration; and
  • the potential for effective mitigation.

5.5.5 For the purpose of this assessment, impacts that have been assessed as being either moderately negative or positive, or greater, are considered to be ‘significant’ in terms of the definitions held within the Environmental Impact Assessment (Scotland) Regulations 1999.