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3. ASSESSMENT OF CUMULATIVE EFFECTS
3.1 The Environmental Assessment (Scotland) Act 2005 requires Responsible Authorities to provide details of possible cumulative and synergistic effects arising from their plan or programme. Based on the detailed assessment findings, the following sections set out possible cumulative and synergistic effects arising for each of the SEA topic areas. The table below also brings together the findings in a summarised format.
3.2 The assessment of cumulative environmental effects took, as a starting point, a worst case scenario that will not arise in practice: inclusion of all of the Candidate Projects as National Developments within NPF2. If this was the case, it would be necessary to assume that all of the schemes would be taken forward within a relatively short timescale, given the development priority that national development status would confer upon them. Although this is not strictly a 'reasonable' scenario, it allows the NPF Team and consultees to gain a clear view of the potential for significant cumulative effects. However, it is extremely unlikely that the Scottish Government will designate all of the projects listed here as National Developments. Therefore, actual cumulative effects can be expected to be much less significant than the analysis here might suggest. The assessment has therefore aimed to highlight the potential for different combinations on Candidate National Developments to result in different environmental effects.
Cumulative effects on biodiversity
3.3 As the summary table shows, most of the Candidate National Developments could have adverse effects on biodiversity. Whilst many negative effects are likely to be mitigated at the project level through appropriate design, siting and construction, some projects nevertheless have the potential to generate significant adverse effects on habitats and species.
3.4 The assessment shows that in many cases significant effects could arise from the scale and locations of the projects, or the likelihood that they would involve land-take or disturbance. In particular, several projects are predicted to have potential effects on the Firth of Forth and its constituent designated sites, including the Forth Replacement Crossing, Grangemouth and Rosyth ports, new baseload power generation and Coastal Protection Measures. These projects may collectively have effects including disturbance of protected bird species and alterations to intertidal habitats which together could reach an unacceptable level. As a result, careful consideration would be required if they were all taken forward under the NPF, either as National Developments or as important parts of the overall spatial strategy for the East of Scotland. Appropriate Assessment is likely to be required for all of these projects.
3.5 In addition, several Candidate National Developments could have repercussions for coastal and marine habitats and species, including: port developments at Grangemouth, Rosyth, Hunterston, Loch Ryan and Dundee. The proposals for energy-based developments including transmission and carbon sequestration could also directly or indirectly affect coastal and marine biodiversity. There are specific issues arising from the Grid Reinforcements projects and in particular the development of a Sub-sea supergrid and the cable proposed from Carradale to Hunterston, as well as connections to the Western Isles. Some purely terrestrial projects could have repercussions for this part of the environment, as a result of their proximity to protected coastal habitats, including the Nigg Complex, Peterhead Port, the five potential clean coal and carbon sequestration projects, the East Coast Rail Line, the Energetica Corridor, Ardeer and the A96 growth corridor. In addition, the proposal for an upgraded oil transfer facility at Sullom Voe increases the level of risk for the marine environment in this location.
3.6 These potential cumulative effects on marine and coastal areas should be considered alongside the recently published Scottish Government Consultation Paper on the Marine Bill. It should, however, also be noted that many of the effects of these developments are not necessarily expected to be significant, as they often temporarily and primarily arise during the construction or installation period. There is likely to be considerable scope for project-level mitigation to ensure that cumulative effects on marine and coastal biodiversity are not significant at the national scale.
3.7 A smaller number of developments could have particular repercussions for freshwater habitats and species, including Edinburgh, Glasgow and Aberdeen Airports, the A7 and A68 improvements, the Waverley Line extension, A90 improvements, Grid Reinforcements, High Speed Rail Links and the Lomond Canal, although many of the specific effects of several of these projects remain uncertain at this stage. Issues arising more generally for the water environment are discussed below.
3.8 Beyond these broad findings, it is not possible at this scale to determine whether any of the combined effects of the developments could have particularly significant implications for any other specific habitat or species. However, it should be noted that many of the protected sites which have been identified as being potentially affected by a range of Candidate Developments are considered important for breeding or migratory bird species. Potential 'in combination' effects of the NPF and other policies on networks of designated sites that support the same types of species are being explored in more detail in the Appropriate Assessment for the NPF. However, it appears unlikely that the cumulative effects of the developments would have significant implications for any single habitat or species, which cannot be addressed in further work at the project level, and in particular by the deployment of effective mitigation measures.
Cumulative effects on population and human health
3.9 No significant adverse effects on population and human health can be predicted with any degree of certainty from the assessment of the Candidate National Developments. However, the assessment suggests that there may be positive and negative effects on several communities. These communities may be defined on the basis of shared interests or sensitivities ('communities of interest') or as a result of their spatial characteristics. Whilst effects are expected to be limited when considered from a national perspective, the following issues have emerged from the review of possible cumulative effects:
- Further consideration of communities adjacent to the proposed airport enhancements will be required, to ensure that short-term construction and long-term operational effects, including changes to air quality, noise and other nuisances, do not have cumulatively unacceptable effects on quality of life.
- There is also potential for some of the larger scale projects to have cumulative effects on some communities, including people living in some rural areas where levels of development, noise and disturbance are currently relatively low.
- Several road improvement projects could generate adverse effects on health, although these vary in type, scale and location and consequently no particularly significant cumulative effects on people suffering from any specific health or social disadvantage are currently expected.
- Some cumulative effects on health may be experienced by some geographically-related communities, including the combined impacts of the Hunterston development, Prestwick Airport Expansion and the Energetics Cluster on communities on the Ayrshire coast. However, all of these projects may also result in improved quality of life. Further consideration of health and quality of life effects in this location may therefore be beneficial, if several of the projects are taken forward.
3.10 Overall, it is not expected that the Candidate National Developments would have adverse repercussions for communities who are particularly vulnerable, including those at risk of social or health deprivation, or those living in peripheral rural areas. Furthermore, no significant cumulative effects are expected for urban or urban fringe communities at this stage, given the spatial distribution of the proposed developments. This will be reviewed as the composition of the suite of National Developments is finalised.
Cumulative effects on climatic factors
3.11 The analysis highlights a number of projects where significant adverse effects on climatic factors are expected. Before exploring this, it is important to recognise that determining the significance of global atmosphere related effects is currently very challenging. Specifically, any increase to Scottish greenhouse gas emissions may appear to be insignificant when viewed in relation to scale and complexity of the international challenge of climate change. However, the Scottish Government recognises that it is important that our national contribution to this global agenda is taken seriously, to ensure that emerging commitments including those proposed for the Scottish Climate Change Bill, can be met.
3.12 If several of the potentially most negative projects for this aspect of the environment were taken forward in the NPF, there is potential for significant cumulative effects to arise at a national scale. Given the level of priority currently attached to climate change mitigation, these cumulative effects could also be of international significance. The Discussion Draft NPF included proposals to enhance Edinburgh and Glasgow airports. If further airport-related developments were to secure National Development status in the proposed NPF, the effects on climatic factors could become cumulatively more significant. Although the way of handling emissions from aviation within a national target for reducing greenhouse gases has yet to be decided, the significance of these effects is high.
3.13 Further climatic issues are likely to be affected by the cumulative influence of the proposals for expanding facilities for shipping. Whilst this appears to be a relatively sustainable option for freight transport, these developments could nevertheless contribute to an overall increase in transport miles, with the shipping sector being a key source of transport borne emissions globally. As a result, these developments have the potential to generate cumulatively significant effects in relation to climate change mitigation targets. As with aviation, the contribution of international transport emissions to domestic targets requires careful interpretation.
3.14 The combined effects of the various proposals for road network improvements could also contribute to emissions from the transport sector, although the scale of this will depend on the balance which is ultimately struck between road and public transport based improvements.
3.15 Proposals for up to five clean coal power stations at Hunterston, Peterhead, Longannet, Cockenzie and Torness in the long term, could cumulatively generate significant emissions, although these could be significantly reduced if proposed carbon sequestration measures are implemented alongside clean coal technology. However, the performance of the energy sector in relation to climate change could be significantly improved if the NPF's potential contribution to renewable energy generation is fully realised.
3.16 It is also useful to note that several of the developments have the potential to generate significant positive effects in relation to climate change, and that if they are all taken forward, the NPF as a whole could be viewed as making a significant cumulatively positive contribution to climate change mitigation. If several or all of the proposals for rail improvements were taken forward and combined with active travel proposals (i.e. Long Distance Trails, Green Network), there is equally the potential for the NPF to make a significant positive contribution to the climate change agenda.
3.17 These potential cumulative effects are being taken into account as part of the process of reviewing the NPF and finalising the suite of National Developments.
Cumulative effects on air quality
3.18 Some of the developments have the potential to generate significant adverse effects on localised air quality, including those located to the west of Edinburgh (Edinburgh Airport and associated developments and the Forth Replacement Crossing). When taken together, these may give rise to negative cumulative effects of some significance, bearing in mind the existence of an Air Quality Management Area ( AQMA) on one of the city's western arterial routes. Some of the road improvements could also generate air quality issues and these have the potential to be cumulatively significant at a national level, if the finalised suite of development were to focus strongly on these proposals.
3.19 However, some of the other projects have the potential, directly or indirectly, to lead to improvements in air quality, and these could equally have significant positive cumulative effects over the long term and in relation to some receptors. For example, the Edinburgh Tram, combined with Electrification of the Glasgow to Edinburgh Railway and the Haymarket Project, could cumulatively lead to a significant improvement in air quality in the centre of Edinburgh where an AQMA has already declared.
3.20 Air quality improvement and decline can have synergistic effects on other environmental receptors, including cultural heritage, water and soil. These have been noted for each of the developments, where clear synergies are identifiable at this level.
Cumulative effects on water
3.21 It is expected that a number of the Candidate National Developments could generate significant negative effects on the water environment, but it is also likely that these will vary in type and location. Developments with potentially significant adverse effects in their own right include Edinburgh Airport (as a result of local flooding issues), High Speed Rail Links to London (due largely to the scale of the project), the Borders Rail Link Extension and the Far North Rail Line (as a result of the sensitivity of their receiving environments), Sullom Voe Oil Transfer Facility (due to heightened risk to an offshore water body), and the Sub-sea Super-grid and Onshore Grid Reinforcements, with each of the latter potentially generating cumulative effects in their own right.
3.22 Taking into account other developments and the likely content of the NPF as a whole, there may be significant cumulative effects arising for the water environment in some areas. This includes the South of Scotland as a result of the combination of proposed road improvements and the Borders Rail Link, which could together affect the River Tweed. As with biodiversity, the potential cumulative effects of the various proposals focusing on the Firth of Forth is also a concern that requires further consideration at a strategic level. Again this is being taken into account within the process of finalising the proposed suite of National Developments.
3.23 Several other developments could directly or indirectly impact on Scotland's firths, including the Nigg Complex (potentially affecting the Cromarty Firth), development of the A96 corridor (having indirect repercussions for the Moray Firth), enhancement of the Far North Railway Line (affecting the Dornoch Firth), and the Glasgow Strategic Drainage Plan, Lomond Canal and the two projects at Hunterston (affecting the Firth of Clyde). As collectively Scotland's firths are of nationally significant environmental and heritage value, the proposed suite of developments should avoid focusing too high a level of pressure on these areas. However, it is currently expected that many of these potentially adverse effects can be mitigated at the project level, including through the application of appropriate regulatory regimes.
3.24 Beyond this, as effects appear to be broadly distributed across the range of water environment issues and given their dispersed geographic locations, no significant negative cumulative effects are expected at this stage. Potential for synergistic effects on soil and biodiversity have been identified in relation to relevant project proposals.
Cumulative effects on soil
3.25 There are relatively few Candidate National Developments which appear likely to generate significant adverse effects on soils. However, the Forth Replacement Crossing is of concern as a result of the likely land take of the development, High Speed Rail Links to London may have significant effects as a result of the scale of the development and the Far North Rail Line and Outer Hebrides National Energy Zone could have significant adverse effects due to the particular sensitivity of the soil environment within which they would be developed. In addition, negative effects are expected to arise from the proposed airport extensions, as a result of the likely extent of landtake and hardstanding required and the level soil sealing that could therefore take place, combined with their predominantly greenfield locations.
3.26 Significant cumulative effects on soil may arise where several of the developments result in substantial losses of prime quality agricultural land. This was raised as a concern in relation to the Forth Replacement Crossing, A90 Improvements, High Speed Rail Links and the Energetica Project, reflecting the relative sensitivity of parts of the east coast in this respect. However, there remains considerable uncertainty as to the type and significance of effects of many of the other developments. As a result, these broad findings should form a starting point for a further review the final suite of developments to ensure that they do not generate a disproportionately high negative cumulative effects on prime quality land. The wider NPF document provides some safeguards against this, through measures such as the prioritisation of brownfield land.
3.27 Soil sealing can have synergistic impacts when considered alongside effects on the water environment, including flooding. Given that several of the developments to the west of Edinburgh could result in significant levels of soil sealing, synergistic effects on current and future flood risk should be noted. This has been referred to where appropriate in relation to the individual project assessments.
3.28 Many of the developments could generate minor or significant positive effects on soil, and cumulatively these effects may be significant at a national scale, depending on the final choice of projects for inclusion in the NPF. In particular, several of the energy projects aim to achieve the shared aims of sustainable energy generation and brownfield reclamation. There could be geographically cumulative significant positive effects on the concentration of derelict and vacant land in the West of Scotland, if the Glasgow Strategic Drainage Plan, Commonwealth Games Facilities, Central Scotland Green Network, Ardeer Energetics Cluster, and Hunterston proposals were to be designated as National Developments in the NPF.
Cumulative effects on cultural heritage
3.29 Several developments could have significant adverse effects on the historic environment. These includes the Forth Replacement Crossing, given the scale of the development and the sensitivity of the environment within which it is set, and the Road Improvements between Glasgow and Fort William, also due to the particular value of the historic environment through which the route passes. High Speed Rail Links to London and Grid Reinforcements could also generate significant negative cultural heritage effects, although these remain largely unknown at this stage and are mainly a result of the possible scale of the projects and their potential for landscape-scale impacts on the historic environment. The extension of the Borders Rail Link, East Coast Rail Line Improvements and Far North Rail Line could also generate potentially significant adverse effects on cultural heritage, although it is not expected that these would be exacerbated by linkages to other projects.
3.30 Some relatively minor effects on the historic environment could become more significant when the potential for cumulative effects is taken into account. This includes the combination of projects within Edinburgh (Edinburgh Tram and the Haymarket Development), which could lead to significant change within a particularly sensitive historic environment. More broadly, there is potential for cumulative effects on certain aspects of cultural heritage, if several of the projects were implemented. This includes effects on industrial and railway heritage, which could be affected by a number of different projects.
3.31 Furthermore, as noted previously (see biodiversity and water issues above) the location of several developments on or close to the coast, within the marine environment and on Scotland's firths raises particular potential for cumulatively significant adverse effects on cultural heritage resources in these areas. Shipping-related developments could add to these effects, with possibly more direct impacts in the form of land take or infrastructure installation and construction. As much of our offshore heritage remains unknown and is not formally designated for protection, it is relatively vulnerable to change. These cumulative effects are being taken into account in identifying the final suite of National Developments.
3.32 These cumulative effects may be significant at a national scale, but it is expected that appropriate project-level mitigation should ensure that the final suite of National Developments is unlikely to lead to an unacceptable level of change to the historic environment in any part of the country, or in relation to any particular type of heritage.
Cumulative effects on landscape
3.33 Effects of the developments on landscape are assessed to be generally mixed, although significant negative effects are expected from several proposals. This includes the Forth Replacement Crossing and Edinburgh Airport where effects arise as a result of a combination of their potential land take, their visibility and the relatively sensitive nature of the landscape within which they are set. Several other transport improvements are also identified as having potentially significant adverse effects on landscape, including the A9 Improvements, Highland Line Upgrade and Borders Rail Link. This is a product of the scale of developments proposed, the sensitivity of their recipient landscapes and the particular repercussions which large-scale transport infrastructure can have for environments that have already been heavily influenced by this type of development, or where such an intervention would result in major change to a currently undeveloped area. In addition, potentially significant effects are predicted from the Road Improvements around Dundee as a result of the sensitivity of the urban fringe location and its role in defining the urban-rural interface, and the Outer Hebrides National Energy Zone, due to the relatively undeveloped and high landscape value of the location, and its likely sensitivity to either primary or secondary effects.
3.34 Cumulative effects may therefore be expected for some specific types of landscape, most notably those which are already heavily altered by linear infrastructure. Care is needed within such areas to avoid cumulative effects resulting in an unacceptable level of change that breaches landscape capacity. The urban fringe location of several developments also raises potentially cumulative landscape effects which could together generate significant changes to the setting of towns and cities, and these may be more cumulatively significant when the broader content of the NPF is taken to into account. This includes cumulative effects arising from growth in the A96 corridor influencing Inverness and development to the West of Edinburgh. In addition, the cumulative pressures on the landscape value of Scotland's firths should also be taken into account.
3.35 However, positive planning, mitigation and opportunities for enhancement at the project level could generate substantial cumulative improvements in some degraded landscapes, particularly when the potential benefits of Green and Habitat Networks are also taken into account. These positive effects are of particular relevance to the Central Belt.
Further geographic analysis of multivariate cumulative effects
3.36 Given that the NPF is essentially a spatial strategy, it is useful to reflect on how the findings relating to each of the environmental topics may interact in any given location. This helps to identify any further geographically concentrated impacts that may be significant and cut across the individual topic areas discussed above.
3.37 Most of these geographic concentrations of effects have already been noted. However, to reiterate, the analysis suggests that there may be particular issues arising from cumulative effects on the following areas:
- Cumulative effects on Scotland's Firths relating to biodiversity, water and landscape. As noted in the SEA of the Discussion Draft, the proposals raise particular challenges for the sustainable management of the Firth of Forth.
- Positive cumulative effects on urban fringe and degraded landscapes in Central Scotland, mainly as a result of the overarching improvements that would arise from the Central Scotland Green Network, which could also mitigate and positively enhance the effects of other developments within the area.
- Cumulative adverse effects on West Edinburgh as a result of the airport enhancement and the Forth Replacement Crossing. Key cumulative effects relating specifically to this area may include a decline in air quality, transport congestion in the long term, increased risk of flooding and significant landscape change.
- Cumulative effects on the Ayrshire Coast, when biodiversity, landscape and coastal management issues from the developments at Hunterston and Ardeer are brought together and considered in light of the vulnerability of this area to the impacts of climate change in the long term.
- Cumulative effects on the East Coast, arising from impacts of several transport and energy developments on high quality agricultural land, potentially also affecting cultural heritage and landscape.
- Cumulative effects on the centre of Edinburgh, with some positive effects, such as improved air quality, being accompanied by potentially negative impacts on the historic environment given the high quality of the townscape and its sensitivity to change.
3.38 All of these sensitivities are being taken into account as an integral part of the process of finalising the content of the proposed NPF and selecting the final proposed list of National Developments.
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