Mitigation and Enhancement Measures

Overview

The SEA aims to prevent, reduce or offset any significant adverse effects as far as possible before mitigation measures are proposed. In addition to preventing or minimising adverse effects, mitigation measures have also been provided for SEA topics where many uncertain effects were predicted in the assessment.

Undertaking the SEA process alongside the A96 Corridor Review throughout the project helps ensure that modifications can be made at the strategic level, for example via alternatives and identifying issues which can be addressed through other relevant Plans, Programmes and Strategies.

Where location-specific mitigation requirements are identified, these are described with appropriate recommendations for future implementation at a project level, as transport interventions are constructed.

In addition to mitigation measures, recommendations for A96 corridor enhancement opportunities have been provided wherever possible.

The mitigation measures and enhancement opportunities consider:

the environmental baseline data provided in Appendix C (Environmental Baseline)
the environmental requirements emerging from the PPS review, provided in Appendix B (Plans, Programmes and Strategies Review)
the SEA objectives provided in Section 6.3
feedback received from the consultation on the SEA Scoping Report, described in Section 5.4, including local context and feasibility
key issues and opportunities identified during the continuing development of the A96 Corridor Review, the EqIA and other Impact Assessments
feedback from the SEA Consultation Authorities and other key stakeholders.

Sections 8.2 to 8.9 provide general strategic mitigation and enhancement recommendations for each of the SEA topics. However, these recommendations will be finalised in the Final Environmental Report, to ensure any location-specific circumstances and other strategic opportunities are considered. The topics of Climatic Factors and Material Assets have been combined due to the synergies between the two topics in relation to sustainability and GHG emissions reduction.

Climatic Factors and Material Assets

Early Planning to Avoid or Reduce Greenhouse Gas Emissions

Planning to avoid or reduce GHG emissions at this strategic planning stage is essential for improving the carbon outcomes of the transport proposals being considered as part of the A96 Corridor Review. This applies to the packages of transport proposals as well as Full Dualling.

The opportunities associated with early planning for carbon reduction include the following:

Challenge the root cause of the need for a new transport asset – explore alternative (no build) solutions to deliver objectives.
Hold carbon opportunities workshops from the earliest planning stage onwards.
Identify strategic carbon reduction opportunities across Scotland as part of the A96 Corridor Review.
Close collaboration with local authority planners to ensure travel demand and trip lengths are reduced.
Reduce the need to travel through supporting more digital technologies to allow more people to access services such as health care appointments, shopping or to work from home. Support for high speed broadband and good mobile phone network coverage will be required in order to reduce the need to travel.
Consider the potential for wider use of behavioural change and other policy solutions and funding instead of providing new infrastructure, for example, the commitment to reduce car kilometres by 20% by 2030.
Re-use and refurbish transport assets, extending their life rather than replacing them.
Support modal shift to active travel and public transport.
Future-proof transport infrastructure to allow the introduction or wider roll-out of emerging zero or low-carbon technologies.
Plan for the wider usage of zero-emission vehicles and low emission vehicles.
Consider how to link transport infrastructure with active travel networks, to make active travel as easy and safe as possible.
Select ‘soft’ rather than ‘hard’ engineering solutions where possible, for example, nature-based solutions.
The design of the project should seek to minimise material usage and the need for earthworks.
Identify the key emission sources associated with each intervention, and how they can be reduced.
Avoid disturbance of vegetation and soils, particularly those with high carbon value for example, peat and carbon-rich soils, wetlands and ancient woodland.

Opportunities for offsetting should be considered where appropriate to contribute towards the national legislative target of achieving net zero emissions by 2045.

Choice of Materials

Although the choice of construction materials is not necessarily a consideration at the strategic planning stage, the decision to construct is often taken at the strategic planning stage. Early planning could potentially avoid the need to use materials with a high embedded carbon content at the construction stage. Each material that could potentially be used in the construction of a new transport asset or in the maintenance of an existing asset has an embodied carbon content associated with it.

The relative impact of each stage will depend upon the material choice. Recycled material will often have a lower carbon footprint as less energy and transport may be required. Heavier weight products may have more impact in transport and more highly processed materials may have most emissions within the manufacturing process.

To minimise emissions from the implementation of packages or Full Dualling, designers should take cognisance of the latest best practice, which is evolving due to advancements in material science, manufacturing and construction processes. This best practice should include identifying low-carbon materials and durable materials that require less maintenance, repair or replacement, in order for the operational emissions of transport assets to be minimised.

From a qualitative perspective, emissions from the implementation of packages or Full Dualling would depend on location, scale, primary materials and construction methods. For instance, interventions requiring significant volumes of concrete and steel such as bridges, junctions and viaducts, would have a high embodied carbon content due to the carbon intensity of the manufacture of the materials used in their construction.

Carbon life cycle assessment should be employed to reflect embodied carbon from demolition, materials, transport and maintenance, as well as the operational carbon associated with heat and power. Carbon life cycle models should calculate the whole life carbon for 2030 and 2045 carbon reduction target dates, in line with legislative requirements.

The delivery of one of the A96 Corridor Review packages or Full Dualling should include provisions for sustainable procurement that accounts for the carbon footprint of materials and products (including country of origin, transport requirements, production process). Consideration should be given to assessing the carbon benefit of prolonged lifespan arising from adequate maintenance. Sustainable procurement provisions should include circular economy principles that prioritise the re-use of materials in construction, use low-carbon construction materials and design principles that allow for materials to be re-used or recycled upon decommissioning. Consideration should also be given to the location of suppliers, to minimise transportation distances, subject to any procurement limitations.

Opportunities to utilise previously developed land to implement one of the A96 Corridor Review packages or Full Dualling should be explored. This may help reduce the requirements for raw materials and reduce the need to encroach on agricultural land or land with biodiversity, heritage, drainage, amenity or landscape value.

Construction Methods

In addition to embedded carbon considerations, construction activities also need to be considered and planned for. Any construction that requires significant earthwork movements will have a high energy demand from earth moving equipment and tipper trucks moving earth around/off/to the site. The source of power supply is a significant factor when assessing emissions from construction – whether the machine is powered by diesel generators or can be plugged into the electricity grid.

Operational maintenance and refurbishment emissions also need to be considered for an asset throughout its operational life. For example, a road will require periodic re-surfacing or a bridge could require the replacement of cables. These emissions tend to be assessed based on assumptions made on the design life of materials to determine how many times they will be replaced during the lifespan. The final consideration for materials is end-of-life emissions, which captures dismantling and disposal. PAS 2080 ( Construction Leadership Council (2019) Guidance Document for PAS 2080 ) provides useful guidance on how to manage carbon emissions throughout the life of an infrastructure project.

Carbon Sequestration Opportunities

The delivery of one of the A96 Corridor Review packages or Full Dualling being considered as part of the A96 Corridor Review should consider how to protect carbon-rich soils, wetlands and other natural resources that are important for carbon sequestration. The Plan should also require the identification of opportunities to create habitats and plant trees (for example, alongside linear transport infrastructure) that will also have carbon sequestration benefits.

Climate Adaptation Opportunities

The potential impacts of climate change on existing and proposed infrastructure need to be planned for and considered in the delivery of one of the A96 Corridor Review packages or Full Dualling being considered as part of the A96 Corridor Review, where possible. Transport infrastructure will need to be future-proofed for projected changes to:

flood risk from all sources
changes to temperature (variations and extremes)
increased risk of landslips, bridge scouring and erosion
increased windspeeds, high intensity rainfall and storminess.

Asset management plans for existing transport infrastructure may therefore need to be revised to respond to the latest climate impact projections. Larger gullies and increased use of SuDS may also be required. Sufficient space may need to be allowed for additional SuDS and permeable surfacing that can accommodate projected trends in rainfall and surface water flooding.

Consideration should also be given to how climate change could affect the spread of invasive species and tree diseases and could therefore have implications for vegetation management and access arrangements associated with the strategic transport network.

The third climate change risk assessment (CCRA3, SNIFFER, 2021) report recommends that more adaptation is particularly needed in relation to the increased risks to transport from high and low temperatures, high winds and lightning. The CCRA also calls for more action to ensure that projected increases in heavy rainfall are factored into long-term renewal programmes, especially for the rail network. Additional adaptation actions include:

improved numerical tools for infrastructure asset owners to predict failures
improved instrumentation and monitoring systems to detect pre-failure slope behaviour linked to decision support systems
more detailed characterisation of engineered soil assets
continued use of slope inspection programs
greater use of soft engineering techniques, such as vegetation management to reinforce vulnerable slopes
enhanced maintenance of drainage systems for roads and railways and increasing drainage capacity in new road infrastructure.

Air Quality

Further environmental assessment will be required to assess air quality impacts for sensitive human and designated ecological habitats across the A96 corridor, and possibly beyond, depending on the extent of any road traffic re-routing, to ensure air quality constraints and opportunities are identified.

There are however opportunities being considered as part of the A96 Corridor Review to promote and facilitate sustainable travel and assist in reducing transport-related air pollution along the corridor. In particular, the SEA recommends where practical:

A suite of active travel recommendations are taken forward and implemented in order to maximise potential modal shift from private vehicles to more sustainable methods of transport and include traffic-free paths wherever feasible, to encourage active travel.
Implement bus priority measures to focus on delivering faster and more reliable journey times and improvements to public transport facilities at bus and railway stations to encourage modal shift.
Improved access to travel opportunities to encourage modal shift in areas with low bus network connectivity or where fixed route services may not be suitable or viable through investment in Demand Responsive Transport (DRT)
Distinct improvements to three areas of railway between Aberdeen and Inverness to enable a more frequent passenger service and the provision of freight facilities to enable intermodal freight to operate.
Improved parking facilities at railway stations to encourage modal shift for medium and long distance travel along the corridor.
Provision of alternative refuelling infrastructure and facilities for electric vehicles along the A96 corridor and local road network to encourage sustainable transport modes.

Population and Human Health

Several of the proposed transport packages and Full Dualling in the A96 Corridor Review are expected to positively impact Population and Human Health, as detailed in the assessment summary of Chapter 7 (Assessment Findings). As well as these benefits, there are strategic opportunities to further enhance the positive effects. In order to fully utilise these benefits and opportunities, the SEA recommends:

A suite of active travel recommendations are taken forward and implemented in order to maximise the potential modal shift from private vehicles to walking, wheeling and cycling.
Seek opportunities for transport infrastructure to reduce community severance and increase accessibility for all.
Any new transport infrastructure, or enhancements to existing infrastructure, should maximise accessibility for those with limited mobility.
Any new transport infrastructure, or enhancements to existing infrastructure, should consider crime and security in the location and design of any schemes.
Plan to reduce the impact of the road network on local communities – for example through the use of low-noise materials, noise barriers and natural buffers – which could also help to improve biodiversity and air quality.
Any new electric charging infrastructure should be accessible to all.
Provision of high-quality, attractive, dense and safe networks for people to walk, wheel and cycle to places of work, essential services, community facilities and spaces and public transport hubs should be considered. These should be provided within communities and link with other communities. Road space reallocation for active travel should be considered to help increase uptake and improve safety.
The provision of real-time information on weather conditions or other disruptions affecting the transport network in public places could potentially improve safety on the network. Any innovations, such as transport apps, may need to be made available in different languages.
New projects within the A96 corridor should aim to improve safety through project design, and also be subject to ongoing safety monitoring. Targeted safety campaigns may also be required, for example campaigns aimed at motorcyclists.
Introduce or extend traffic calming measures.
Install sensors and communication technology to reduce traffic idling and improve flow.
Seek opportunities to implement active travel measures in, or close to areas with concentrations of poor health, low levels of physical activity, areas of deprivation or areas where the air quality is poor. Consideration could be given to loaning bicycles or equipment to those who cannot afford to buy or run them.
The development of one of the transport packages or Full Dualling should prioritise the provision of high-quality green or blue infrastructure (natural spaces, including waterways) or improve accessibility to existing green and blue infrastructure. This is likely to lead to significant benefits for mental and physical health, as well as sense of place and local pride.
A communications strategy should be implemented to keep local communities informed of the progress of any A96 transport infrastructure construction and to provide channels for enquires/inputs/complaints. This may include a community liaison officer being appointed to facilitate regular meetings with local communities.

Water Environment

The development of one of the transport packages or Full Dualling will provide opportunities to reduce flood risk and increase the installation of SuDS which will help maintain or improve water quality and prevent flooding. In general terms, avoiding watercourses and areas designated for the protection of aquifers would be prudent. Consideration will also need to be given to potential disturbance to sites with historic contamination due to previous land uses, as groundworks could potentially release pollutants into soil and water. The implementation of climate adaptation measures (see Section 8.2) and nature-based solutions, as described in Section 8.6, will also help maintain or improve water quality through the protection of soil and reduction of erosion. Opportunities to enhance the amenity, accessibility and biodiversity value of SuDS should also be pursued.

Appropriate pollution control for all polluting activities is required during construction to prevent the deterioration of the status of water bodies. Considering SEPA guidelines, pre and post construction water quality monitoring may be required where deemed necessary. Similarly, hydrogeology and geotechnical surveys may be necessary to determine groundwater levels within the vicinity of any transport proposals. Specific measures may be required to prevent or limit the input of pollutants to groundwater.

The design of any transport proposals being considered as part of any of the transport packages or Full Dualling should be undertaken in line with best practice and relevant guidance, considering the requirements of The Water Environment (Controlled Activities) (Scotland) Regulations 2011 (as amended) (CAR) and in consultation with SEPA.

Site-specific flood risk assessments should be undertaken in accordance with the Design Manual for Roads and Bridges (DMRB), SEPA and other relevant guidance, as more localised detail becomes available at each design stage. Across all design stages, watercourse crossings should seek to cause no increase in flood risk to sensitive receptors and should improve upon the present situation. Additionally, new infrastructure within the functional floodplain should be avoided or limited, and adequate compensatory flood storage provided where appropriate.

Biodiversity

The following mitigation measures will be required for any one of the transport packages or Full Dualling in relation to biodiversity.

Further environmental assessment will need to be undertaken to ensure site-level biodiversity constraints and opportunities are identified and thereby allow any negative effects on biodiversity to be avoided or minimised. This includes consideration of designated and undesignated biodiversity. This environmental assessment will need to prioritise delivering nature-based solutions with multiple benefits and achieving positive effects for biodiversity, such as the Scottish Government’s agreement to protect at least 30% of Scotland’s land and seas by 2030 (also known as the ‘30 by 30’ commitment) and to highly protect 10% ( NatureScot (2022) 30 by 30 explained: Background on 30x30 to help inform the co-design of Scotland's 30x30 framework. ) .

Where new transport infrastructure is proposed, particularly linear infrastructure, opportunities to provide green or blue infrastructure for biodiversity benefits and climate resilience should be explored – for example to provide new wildlife corridors between biodiversity sites. Careful design will be required to ensure any new wildlife corridors support connectivity without facilitating the spread of invasive non-native species. This green or blue infrastructure is also likely to provide benefits for other SEA topics – for example, tree planting can provide shading and cooling and potentially intercept airborne particulate matter. A number of potential opportunities are described below:

Opportunities to enhance habitats with a high carbon sink value and amenity or accessibility value should be explored.
Opportunities to restore ecosystems and ensure their future protection should be explored.
If any planting can be done alongside transport infrastructure, native species should be prioritised.
New transport projects should also look to deliver positive effects for biodiversity by integrating nature into new or retro-fitted infrastructure projects.
Where new transport infrastructure is proposed, this should seek to reduce overall land-take and avoid sites designated for their biological interest, particularly sites of international and national importance.
Flood risk management and changing ecosystems must be factored into future development to ensure nature-based adaptation.
The project should seek to ensure permeability for wildlife. This could include, where appropriate, the provision of mammal crossings.
The loss of woodland and other notable habitats should be replaced through tailored planting mitigation to ensure the ecological connections between these habitats are maintained or improved.
Further engagement with NatureScot will be required in relation to the development of any new infrastructure, improvements to existing infrastructure or provision of green and blue infrastructure. This will allow any biodiversity opportunities to be maximised.

As discussed in Section 1.5, an HRA is being prepared. Further appraisal of the potential for the transport packages or Full Dualling to result in adverse effects on the integrity of 11 designated European sites is required as part of the next stage of the HRA process of the A96 Corridor Review – the Appropriate Assessment (AA). The AA will include detailed mitigation measures to protect European Sites.

Geology and Soils

The following mitigation measures will be required in relation to Geology and Soils:

Further environmental assessment will need to be undertaken to ensure site-level development avoids any adverse effects on nationally important carbon-rich soils, deep peat and priority peatland under Class 1 (areas likely to be of high conservation value) and Class 2 (areas of potentially high conservation value and restoration potential), areas important for carbon sequestration and sites designated for their geological interest, such as Geological Conservation Review (GCR) sites.
Further environmental assessment will also help identify opportunities to protect and/or enhance the health and biodiversity of soils, and their role in helping control biochemical processes for nutrient cycles, GHG emissions, pollution amongst other ecosystem services.
Where new transport infrastructure is required, prioritise the development of vacant and derelict land to avoid or minimise loss of undisturbed soils. Where soils or peat are unavoidably disturbed, mitigation should be considered which reduces organic matter loss, contamination, erosion risk, compaction/structural degradation and soil biodiversity is maintained.

Cultural Heritage

The role that the historic environment plays in existing transport infrastructure needs to be recognised in the planning of any of the transport packages or Full Dualling.

The following mitigation measures will be required in relation to cultural heritage:

Further environmental assessment will need to be undertaken to ensure site-level heritage constraints and opportunities are identified. This includes consideration of designated and undesignated heritage assets. For rail infrastructure, the environmental assessment will also need to consider the potential impacts associated with access work, electrification and issues for historic bridges and other heritage assets relating to gauge clearance work. Consultation with HES is likely to be required for site-specific work at heritage assets on the transport network, such as railway stations and road bridges.
At the project level, the location and design of transport proposals developed for any one of the transport packages or Full Dualling should avoid direct effects on cultural heritage resources or their setting, where feasible. Opportunities to improve the existing setting of cultural heritage resources should also be considered and discussed with Historic Environment Scotland.
At the project level, opportunities should be sought to maintain, restore and repurpose historic assets to support sustainable placemaking (in line with the NPF4). This includes adherence to circular economy principles – for example, some historic assets could potentially be restored or deconstructed and re-used or repurposed rather than demolished and disposed of. This will align with the HES Climate Action Plan 2020-2025 ( Historic Environment Scotland (2020) Climate Action Plan 2020 - 2025. ) and help meet Scotland’s Zero Waste targets of 70% recycling by 2025 and no more than 5% to landfill by 2025. An emphasis on maintenance, repair and re-use would also align the Sustainable Investment Hierarchy in the Infrastructure Investment Plan ( Scottish Government (2021) A National Mission with Local Impact: Infrastructure Investment Plan for Scotland 2021-22 to 2025-26. ) and the Skills Investment Plan.
Consider how to maintain or improve existing historic infrastructure, such as the canal network, former railway lines and military roads, to allow it to continue playing a key role in the active travel network. This may require re-use, repair and maintenance, in consultation with HES.
Consider how to maintain or improve active travel access to cultural heritage resources.
Further engagement with HES will be required in relation to the development of any new infrastructure or improvements to existing infrastructure.

Landscape and Visual Amenity

The following mitigation measures will be required for the transport one of the transport packages or Full Dualling in relation to Landscape and Visual Amenity:

Embed landscape mitigation into design, including careful route selection and alignments, input into the design of structures and form and extent of earthworks, woodland planting and cutting slopes, with suitable cognisance of the surrounding landscape, and avoiding or reducing the loss of existing natural landscapes.
Opportunities to improve the public realm and enhance sense of place and sense of journey should be considered.
Opportunities to maximise landscape benefits should be explored, for example through focusing development on vacant and derelict land.
In built-up areas it is important to avoid effects on designated areas such as Conservation Areas, or direct effects on buildings/structures listed for their architectural significance or their setting.
Transport infrastructure development proposals should be designed to a high quality so that the scale and nature of the development contributes positively to the character and sense of place of the area. Any new signage and infrastructure for pedestrians, cyclists and wheelers should be designed to be sympathetic to local distinctiveness but also be clear and informative.
Minimise the loss of existing vegetation wherever practicable and in particular retain mature trees and woodland and ancient woodland. Where loss of existing vegetation is unavoidable, seek to provide replacement planting which corresponds to, or exceeds, the natural capital value of the landscape elements and ecosystem services lost as a result of the intervention in keeping with landscape character.
Ensure the design of SuDS features considers opportunities for multi-functionality and delivers amenity and biodiversity benefits as well as attenuation and treatment. Mitigate adverse landscape and visual effects by integrating with surrounding topography, using natural characteristics in design and planting with native aquatic and terrestrial species suitable to local context to provide wildlife habitat and visual interest in keeping with landscape character.
Take account of local species composition, forest and woodland strategies, landscape character, climate change adaptation and biosecurity threats when developing planting proposals.
Develop planting and landscape proposals that integrate with the surrounding landscape and secure positive effects for biodiversity and landscape character. Prioritise native and local species in planting proposals.
Maintain and, where feasible, enhance ecological, landscape, active travel and recreational connectivity and minimise fragmentation.
Consider and contribute towards local and strategic biodiversity priorities through planting proposals.
Secure adequate land to allow integrated solutions. This may include allowance for grading-out embankments and cuttings to smoothly transition into surrounding landforms, or to later return land to agriculture and minimise the final scheme footprints.
Retain existing features and re-use site-won materials – for example, approximately balancing cut and fill, storing soils appropriately for re-use and translocating some plants and habitats.
Design for low maintenance and management of soft estate.
Preserve vistas/focal points from key viewpoints and maintain or enhance the evolving narrative of any existing scenic routes (walking, wheeling, cycling, hiking or driving), and ensure long-term management of these facilities to maintain views.
Avoid or minimise light pollution to reduce any negative landscape, visual and biodiversity effects.
Consult with NatureScot and local councils about potential landscape constraints and opportunities associated with specific interventions.

Further Environmental Assessment

As discussed in the sections above, further environmental assessment will be required at the project level. Individual transport proposals that arise from the A96 Corridor Review should be subject to the usual consideration through the relevant consenting process, supplemented where appropriate by Environmental Impact Assessment (EIA), Habitats Regulations Appraisal (HRA), and via site controls and Environmental Management Plans. This environmental assessment will therefore enable the clear identification of constraints, opportunities and ecosystem services at the site/project level, which in turn will allow the development of targeted and detailed mitigation, enhancement and monitoring measures.

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