5 Mitigation

5.1 General Principles of Mitigation

The SEA Act requires the ER to provide information regarding ‘measures envisaged to prevent, reduce and as fully as possible offset any significant adverse effects on the environment of implementing the plan or programme’. Section 7.3 of the draft ER outlines mitigation proposals and makes clear that mitigation is intended to be taken forward as an intervention progresses to further stages of the decision making process. It is a central component and consideration of the development of the interventions arising from STPR.

The draft ER established generic mitigation measures and identified likely residual effects after mitigation. The mitigation approach followed the hierarchy of avoidance, reduction and remedy in line with the EIA Handbook.

  • Avoidance aims to avoid any adverse impacts, including alternative or ‘do nothing’ options;
  • Reduction aims to reduce unavoidable adverse impacts of the project;
  • Remedy or Compensatory measures or compensation aim to offset or compensate for residual adverse effects which cannot be avoided or further reduced; and
  • Enhancement / Net Benefit / New Benefit is the enhancement of the natural heritage interest of a site or area because adverse effects are limited in scope and scale, and the programme includes improved management or new habitats or features, which are better than the prospective management, or the habitats or features present there now.

No consultation responses have been received to suggest altering the fundamental structure of this hierarchy. It is envisaged, therefore, that some form of environmental assessment will be undertaken at each stage of developing an STPR intervention. The majority of interventions will be subject to EIA at some stage. It is also likely that many interventions may have the potential to impact at a relatively local level, in addition to their wider impacts. Such interventions will be addressed at the project level.

As an intervention develops, each of the stages of assessment will consider the likely significant impacts and remaining uncertainties. These will be addressed further through appropriate mitigation and by following the mitigation hierarchy of avoidance, reduction, remedy and offsetting.

Depending on the actual form and location of works there could be some adverse impacts on local or regional biodiversity, geological and water resources and cultural heritage resources. These would however be minimised through sensitive siting and design in line with environmental legislative requirements (The Transport and Works (Scotland) Act, 2007 (Consents under Enactments) Regulations, 2007) and best practice according to the Design Manual for Roads and bridges (DMRB). Some interventions, such as proposals to reconfigure the national rail timetable, might be expected to have minimal environmental impact. Never the less, it is recognised that this cannot be assumed.

In addition, where relevant, a Code of Construction Practice (CoCP) will be produced as part of the EIA process. The provisions of the relevant CoCP will be included in the Contract for the construction of the interventions where such codes are assessed as being necessary. In these cases, the Contractor will be obliged to comply fully with the terms of the CoCP. It is not expected that all of the interventions ultimately delivered from STPR will require a CoCP, but the need to consider its appropriate use is recognised, particularly for infrastructure based interventions.

5.2 Mitigation Commitments

Following consultation on the ER and, based on comments received primarily from the Consultation Authorities, the proposed mitigation measures have been revised or clarified. This section describes the revised mitigation commitments for the STPR.

5.2.1 Biodiversity Mitigation Commitments

There are a number of mitigation measures, detailed below, which are envisaged to avoid or reduce adverse effects on the biodiversity topic.

  • During the development of interventions, areas of recognised biodiversity importance should, where practicable, be avoided and the location of new infrastructure should recognise the presence of any protected species and habitats. It should also be designed to avoid or limit the fragmentation of habitats, including non-designated habitats where appropriate.

It is also proposed that, due to restrictions placed on the form and siting of works by the requirements of the Habitats Directive, all potential adverse effects on European designated sites should be avoided. In exceptional cases where complete avoidance of impacts is not possible the provisions of Article 6(4) of the Directive may be explored which, in the absence of alternatives, allows consideration of imperative reasons of overriding public interest (IROPI). Where species or habitats are likely to be effected, a minimum of a Phase 1 habitat and species survey would be required. Where possible, land take from greenfield land should be avoided; all works should be undertaken in full accordance with DMRB. Particular note will be taken of the following;

  • The need to consider potential impact on local environments and designated habitats that might be associated with smaller schemes and localised proposals; and,
  • The consideration of potential impacts on biodiversity and habitat fragmentation in non designated areas during the design stage of interventions;
  • The Appropriate Assessment, set out in Appendix 8 of the draft ER, details specific mitigation measures for those interventions with a potential effect on Natura 2000 Sites. The mitigation measures are detailed on a site by site basis. The assessment indicates that, at a strategic level, it is possible to carry out the proposed interventions in such a way that there would be no adverse effects on the integrity of the designation, if the proposed mitigation is implemented.

If these interventions are carried forward to a more advanced stage, the design and development process will require and be driven by further refinement of the Appropriate Assessment. The general areas covered by the Appropriate Assessment Mitigation include: disturbance of species during construction and operation; pollution control and land take from habitats;

  • Landscape maintenance should be undertaken by means that conserve, and where possible enhance, the development of species and their habitats which are protected or of high nature conservation interest in or adjacent to interventions;
  • Land drainage characteristics necessary to support a diverse flora and fauna or particular species of interest already found on the site should be conserved;
  • Cumulative effects of interventions should be considered, particularly where they share a common or closely associated corridor. The potential in-combination impacts of the A9 upgrade and Highland Mainline upgrade may be seen as examples; and,
  • Habitats, including (without limitation) native woodland, woodland edge, wetlands, species rich grassland and heathland, rock and scree should be managed so as to conserve, and where possible enhance their nature conservation value. All underpasses and over structures should be designed and located so as to maximise the opportunity for wildlife crossing, so assisting in reducing fragmentation, whilst not impairing the function of the structure. The provision of vegetated margins should be considered and all opportunities should be taken for locating suitable structures as close as practicable to likely wildlife crossing points.

5.2.2 Population Mitigation Commitments

The mitigation measures detailed below, are envisaged to avoid or reduce adverse effects on the population:

  • Considering impacts which could result from temporary or permanent disruptions to walking, cycling, equestrian facilities or long distance routes, regional routes and local routes;
  • The assessment of transport projects, both infrastructure works and policy measures, should include consideration of the impacts on people’s ability to use outdoor access resources; and,
  • Establishing community liaison group(s), and liaising at appropriate points in the development and delivery period, in order to maintain good community relations, seek relevant contributions and ensure the local population are aware of issues and progress.

5.2.3 Noise Mitigation Commitments

A number of mitigation measures have been identified, which if implemented, would avoid or reduce adverse effects relating to the environmental topic of noise.

  • Noise reduction mitigation should include road surfaces which generate lower levels of traffic noise and / or noise barriers, where adjacent properties could be affected;
  • The routeing of construction traffic should be detailed in a transport management plan before construction begins to reduce effects on sensitive receptors; and,
  • As part of taking the Transportation Noise Action Plan forward, we will explore the links between STPR and Candidate Noise Management Areas (CNMA) to inform whether these should become Noise Management Areas (NMA). Thereafter we will consider how this impacts on the development for interventions.

5.2.4 Water Mitigation Commitments

A number of mitigation commitments have been identified which are detailed below. These will avoid or reduce adverse effects relating to the environmental topic of water;

  • All activities associated with interventions should be carried out in accordance with the Controlled Activities Regulations (CAR). The regulations relate both to construction and operational impacts. In order to ensure proportionate controls over activities, the Regulations provide for three levels of control: General Binding Rules (GBR), Registrations and Water Use Licences. If site-specific controls are required and, in particular, if constraints upon the activity are to be imposed then the activity should be authorised using a licence;
  • A detailed drainage design incorporating Sustainable Urban Drainage Systems (SUDS) should be considered to address flooding and potential drainage issues as a result of constructing and operating the intervention, where this is appropriate;
  • Water pollution control measures should be provided to ensure that pollutant concentrations in receiving waters remain within the limits for the appropriate water quality objective for the watercourse or where this is not available, for the current water quality classification; and,
  • For discharges to ground water, pollution control and containment measures should be designed and installed as necessary to ensure compliance of discharges with the Groundwater regulations.

5.2.5 Soils and Geology Mitigation Commitments

Mitigation measures have been identified which if implemented, would avoid or reduce adverse effects relating to the environmental topic of soils and geology:

  • The development of interventions should, wherever practicable, avoid crossing or adversely affecting geologically designated sites or valuable soil resources including geological SSSI’s and Regionally Important Geological Sites; and,
  • Consultation at the local level to avoid fragmentation of agricultural resources.

5.2.6 Cultural Heritage Mitigation Commitments

A number of mitigation commitments have been identified, which if implemented, would avoid or reduce adverse effects relating to the environmental topic of Cultural Heritage:

  • The development of interventions should consider the potential for these interventions to affect, either by crossing or affecting the setting of, internationally or nationally important cultural heritage features, including designated or proposed World Heritage Sites, archaeological sites, Scheduled Monuments or Listed Buildings;
  • Specific consideration of siting and design should be taken at locations where sensitive cultural heritage and features are present;
  • Interventions should be carried out in line with the Transport & Works (Scotland) Act, the guidance, due be launched during 2009/10, which replaces the Memorandum of Guidance on Listed Buildings and Conservation Areas (revised 1998) (the Memorandum) and Scottish Planning Policy 23: Planning and the Historic Environment (SPP 23), or its replacement consolidated Planning Policy Note; and,
  • The development of interventions will recognise the need for project assessments to consider mitigation for all significant cultural heritage impacts and for the ensuing proposals to set out who will be responsible for undertaking and managing mitigation works.

5.2.7 Material Assets Mitigation Commitments

The mitigation measure for material assets is detailed below, would reduce adverse effects.

  • Fully consider the use of secondary or recycled aggregates in the construction of interventions. There are no construction and demolition recycling targets detailed in the Scottish National Waste Strategy, however in England the Government (DEFRA) is considering a target to halve the amount of construction, demolition and excavation waste going to landfill by 2012, as a result of waste reduction, reuse and recycling.

5.2.8 Landscape Mitigation Commitments

A number of mitigation measures have been identified and are outlined below. It is proposed that these be implemented and so, contribute to avoiding or reducing adverse effects relating to the topic of Landscape:

  • The design of interventions should, in the first instance, consider potential landscape impacts at the earliest possible stage;
  • Project environmental appraisals should consider the impact on all landscapes, including not only those designated as National Scenic Areas or National Parks or designated through local landscape designations, but also all other landscapes. Design and mitigation of proposal likely to have significant effects on such areas should be aimed at if possible avoiding, and if not possible then minimising, adverse visual and landscape impacts;
  • All works should consider the surrounding landscape and carrying out appropriate planting, ground modelling and fencing. Structural treatments should be carried out so as to soften the appearance of any works, environmental barriers or engineering features of the intervention with regard to views from the surrounding landscape and the intervention itself;
  • Hard landscape and materials should be selected and maintained, where practicable to suit local character and retain visual amenity;
  • Visual screening should be used to reduce visual effects on the population;
  • Consideration will be given to how views from the road or railway will be promoted; and,
  • Impacts on Scotland’s areas of wild land will also be taken into account where appropriate.

5.2.9 Air Quality Mitigation Commitments

Air quality and climate change are important considerations in the design and development of any interventions arising from the STPR.

  • We will seek to reduce the carbon footprint of interventions as part of their design, procurement and implementation;
  • We will monitor air quality both during development and operation of an intervention; and,
  • We will seek opportunities to power electrified rail services from renewable power sources.