Planning Advice Note 1/2010: strategic environmental assessment of development plans

Provides advice on how the requirements of the Environmental Assessment (Scotland) Act 2005 can be met within the development planning process.



Key point: Use scoping more effectively to help focus the assessment. 5.1 Comprehensive scoping of the SEA forms the foundation for a focused assessment. A combination of careful consideration of the hierarchy within which the plan sits (tiering), good use of information and timely consultation can help to make better use of the scoping stage to inform the assessment as a whole. The SEA Tool Kit provides guidance on the content of scoping reports. The analysis within them does not need to be lengthy or exhaustive: a comprehensive scoping exercise need not necessarily generate a lengthy scoping report. As with environmental reports, it is important to focus on the most relevant issues.

5.2 A more proportionate and focused approach to scoping itself can be achieved in the following ways:

  • Key point: Focus on what this review of environmental objectives actually means for the assessment. Review of wider environmental objectives. Schedule 3(5) of the 2005 Act requires the environmental report to identify the environmental protection objectives which are relevant to the development plan, and explain the way those objectives and any environmental considerations have been taken into account during its preparation. Often, Responsible Authorities begin this part of the assessment at the scoping stage, and reviews can be exhaustive and lack focus. It is important that the purpose of the review remains clear throughout: apart from meeting the requirements of the 2005 Act, it ensures that the SEA and the plan it is assessing are properly set within the broader existing framework of environmental objectives. Therefore, reviews should be closely guided by the geographical extent of the plan and the topics it covers, and objectives should be excluded if there are no clear connections between them and the plan which is being assessed. There are opportunities to learn from and roll forward similar reviews which have been undertaken in other SEAs. It is acceptable to simply summarise or refer to this work in the scoping report and to cross-refer or extract key points, as opposed to fully duplicating them in each assessment.
  • Key point: SEA baseline information can be just as useful for the preparation of the plan. Environmental baseline: As with the wider review of environmental objectives, this is often commenced at scoping, but there is no requirement to include a detailed assessment within the scoping report itself. It is clear that many early SEAs were hindered by excessive data collection and descriptive baselines which did not inform the findings of the assessment in a meaningful way. Key point: Spatial analysis of the baseline (e.g. constraints mapping) can provide a clearer picture of the existing situation. Baseline information should only be gathered and referred to in SEA reports where it is really relevant. Some planning authorities have benefited from the preparation of area-wide state of the environment reports, which can be used in a range of different SEAs. Such information can be as valuable for the preparation of the development plan as it is for the SEA. It is important to ensure that in addition to generic information (that applies council-wide) the reports include information that is specific to the effects of the development plan in question. If there proved to be no plan-specific information, then this should be explained in the report. Baseline data can be presented in many different forms, but development plans can be well served by information which is organised and presented spatially, using GIS where possible. This information can be collected and used corporately.
  • Identification of environmental problems: This part of the SEA can help to focus the assessment on relevant aspects of the environment and potentially significant effects, and can also usefully inform the content of the development plan (particularly the monitoring statement and the main issues report).
  • Key point: Try to scope out effects which, regardless of the findings of the SEA, are clearly subject to existing mitigation mechanisms. Defining potential significant environmental effects and building in 'assumed mitigation'. Particularly in the SEA of development plans, there is a tendency to scope environmental topics in, rather than exclude them. Assumed mitigation refers to those factors that can reasonably be taken into account when potential effects are being identified at the scoping stage. For example, it may be assumed that certain activities affecting the water environment would be subject to approval via the Controlled Activities Regulations ( CAR). 6 Used with care, such mitigation could be taken into account at the scoping stage, to differentiate between generic effects from a typical development plan, and the really significant environmental effects that are expected within a specific geographic area. However, authorities must be confident that the mitigation is appropriate, robust and will be implemented as expected.


Key point: Make informal contact with the Consultation Authorities early in the process. 5.3 There is a statutory requirement to consult on the scope of the SEA with the three CAs: the Scottish Environment Protection Agency, Scottish Natural Heritage, and Historic Scotland. However, it is not necessary to wait until the scoping report is written before contacting them. The CAs are also key agencies 7 within the planning process, and there should therefore be significant opportunities for combining consultation on the SEA and the plan itself. It may be useful, for example, to retain SEA as a standing item on all development plan-related meetings with these agencies. Early engagement in SEA has been shown to have a number of advantages. Discussions can explore whether:

  • the key environmental issues are correctly identified;
  • there are significant gaps in the contextual or baseline analysis (including recent updates to environmental policy);
  • crucially, the methods proposed are appropriate and reflect the scale and level of detail within the plan; and
  • the proposed consultation is considered to be sufficiently early and effective.

5.4 Primary data collection, e.g. site survey work, is not normally required within SEA. There will usually be opportunities to draw on studies undertaken to inform the evidence base for the development plan (e.g. landscape character assessments). The CAs are an excellent source of advice on data availability and this should be sought early in the process.

5.5 Consultation on the scoping report should form one strand of the pre-main issues report involvement required of the key agencies by the Planning etc. (Scotland) Act 2006. The statutory five-week consultation period for the SEA scoping report should be built into the plan-making timescale, to avoid unnecessary delays.


Key point: Long environmental reports can undermine the transparency of the SEA process. 5.6 The excessive length of environmental reports is a common concern. This may have been exacerbated recently by growing concerns about achieving legal compliance in SEA.

5.7 To improve transparency and ensure that the SEA outputs better match the aspiration for concise development plans, the following measures are recommended:

  • Key point: Use techniques to ensure that the significant effects of the plan can be clearly identified from the environmental report. Focus only on reporting the significant environmental effects, whilst recognising that synergistic and cumulative effects can be generated from minor effects (see further advice on significant effects in paragraphs 5.12 to 5.17).
  • Use appendices to present more detailed work and the environmental report to focus on key results. Such appendices could be more accessible and of greater use to others if they can also be made available electronically.
  • Be selective about the use of matrices to present results. Used appropriately, matrices can help with consideration of synergistic and cumulative effects and can reassure the reader that the assessment has been systematic and comprehensive. However, they can also appear repetitive, be difficult to follow and lengthy. There are ways to streamline the presentation of information within matrices. For example, as mentioned previously, the assessment can be undertaken for a group of policies covering the same topic, thereby avoiding the production of a matrix for each individual policy or proposal. It is also possible to use matrices to undertake the assessment and to report the results using a narrative format.
  • Use of summaries and highlighting of key points throughout the report.

5.8 Proportionality in SEA reporting has a key role to play in making better use of resources (see Section 6).


5.9 It is for the planning authority to define the scope and level of detail to be included in the assessment, and this has to be discussed at the scoping stage. Any assumptions that underpin assessments should be made explicit in the environmental report. To undertake the assessment itself, the following methods are commonly applied:

  • The use of SEA objectives to assess the plan can help to articulate the direction in which the plan should be moving from an environmental perspective, but can be difficult to define and apply in a meaningful way. Qualitative judgements of the performance of the plan in relation to SEA objectives can be significantly strengthened by the application of baseline evidence to the findings.
  • A thematic approach can provide a reasonable impression of the environmental performance of a plan as a whole and be particularly helpful for considering strategic aims. However, it may be too "broad brushed" for Local Development Plans.
  • Research has demonstrated that there is significant untapped potential for map-based analysis in the SEA of development plans, for example the use of constraints mapping and overlay analysis. Such map-based analysis can be used in the assessment of sites in the main issues report or, alternatively, as part of the site selection process.
  • Planning authorities often use checklists for the assessment of sites from a planning perspective. These checklists routinely include planning, economic and social criteria. Some environmental criteria (e.g. proximity to nature conservation sites) are often included. Planning authorities may wish to consider widening the environmental criteria contained in these checklists to include all of those set out in Schedule 3(6) of the 2005 Act, thereby integrating SEA into the planning appraisal of sites (see paragraph 4.21).

5.10 Early consideration and discussion of the most appropriate approach for the plan in question at the scoping stage will benefit subsequent assessment.

5.11 Topics that those undertaking SEA have often struggled to interpret include: climatic factors, population and human health, and material assets. As a quick guide to these headings, the following issues are likely to be most relevant to development plan SEAs:

  • Climatic factors: greenhouse gas emissions and mitigation; effects of future climate change (e.g. habitats, landscape, flood risk); long-term adaptation to climate change impacts.
  • Population and human health: proximity to pollution, noise, vibration and environmental problems (e.g. derelict and contaminated land); outdoor access.
  • Material assets: existing land use (including recreation and access); environmental infrastructure such as flood defences, minerals (including sterilisation of resources and secondary effects arising from extraction and transport).


5.12 Identifying significant environmental effects is crucial. These are the effects of actual outcomes from the plan, as opposed to judgements on the alignment between the policies of the plan and the SEA objectives. SEA objectives should not be confused with those of the plan. They may overlap, but have different functions.

Key point: Define significance criteria early in the process and apply them consistently. 5.13 Whether or not an environmental effect is significant depends on a number of factors. It is a judgement to be made in each case. Schedule 2 of the 2005 Act identifies the key characteristics of plans, environmental effects and the area likely to be affected in determining significance. These include inter alia:

  • Probability of effects. Greater likelihood of effects is likely to increase significance.
  • Frequency, duration and reversibility. Will an effect occur only once? Will it be temporary or permanent?
  • Magnitude and spatial extent. How large an area is affected? Will the effect comprise loss or damage of a feature?
  • Sensitivity of the plan's environment. Does the area have environmental value (e.g. protected status)? Are there environmental issues identified by the environmental baseline, e.g. decline in quality or quantity of resources?

5.14 Significance will therefore depend on, amongst other things, the nature, scale and duration of the effect, whether the effect will be reversed (and if so, how quickly), how sensitive to change or recovery the environmental factors affected (e.g. wildlife or landscapes) may be and how important they are. Significance can also depend, in some cases, on the type of development or land use change that is proposed and its location. For example, the effect of a proposed use of land for a noisy recreation or sport would be more significant if located near to housing areas or a hospital, or in an area enjoyed for its tranquillity. If located next to a site of heavy industry, the increase in noise may not have a significant effect.

5.15 In practice, combining some or all of these criteria should help to identify the most significant environmental effects of the plan. In some circumstances large-scale effects may not necessarily be significant, whereas some small-scale effects could become a concern if they are impacting on a particularly sensitive environment. Equally, multiple minor negative effects may become much more significant when considered cumulatively within a certain area or in relation to a specific aspect of the environment.

5.16 Clear criteria or decision rules for characterising effects and assessing significance should be defined early in the process and consistently applied to the SEA findings. Planning authorities may wish to consult the CAs on the definition of significance criteria at the scoping stage.

5.17 Trying to capture the characterisation of effects in a matrix can become complicated and may be best achieved after the initial assessment has been undertaken.


Key point: Identification of cumulative effects can be challenging but may add particular value to the assessment of development plans. 5.18 Cumulative effects can be particularly important within a development plan SEA, given the breadth of issues that plans address and their emphasis on providing a spatial vision for an area.

5.19 The analysis of cumulative effects is often presented in the form of a summary matrix that brings together the results from the assessment of individual policies and proposals. Similar assessment findings from different parts of the plan on the same environmental topic can sometimes, but do not automatically, indicate the presence of a cumulative effect. For development plans, possible cumulative effects could be identified by:

  • Key point: Remember cumulative effects are different from multiple or large-scale effects. There are different ways of defining cumulative effects. considering how effects might work together in a single geographic area to establish, for example, whether the development strategy is placing too much pressure on the environment to the point that capacity may be breached; or
  • identifying whether specific environmental assets (e.g. areas of ancient woodland, specific habitats or certain species, specific soils or landscape character types) that are distributed across the plan area might be affected by different policies from within the plan; or
  • thinking beyond the confines of the plan to identify how it might add to effects from other plans or strategies (e.g. the local transport strategy, and local biodiversity action plan).

5.20 Time should be built into the SEA to allow for a good assessment of cumulative effects. It is essential to consider how significant negative cumulative effects might be avoided or mitigated.

5.21 Synergistic effects arise where two or more effects from multiple policies combine to create an effect that is greater than that which would arise from the single policy or proposal. An example within a development plan might include synergistic positive effects arising from a concerted approach within a plan for regeneration, or could arise as a result of the interrelationships between different environmental effects.


5.22 Schedule 3 of the 2005 Act requires authorities to identify appropriate mitigation measures to prevent, reduce or offset any negative effects from the plan. To ensure that these measures are robust and provide assurance that they will be taken forward, it is useful to define each action, explain the reasons for them, and identify responsible partners. Timescales for taking forward mitigation and expected outcomes should also be defined where possible, and measures should be linked with monitoring.


Email: Central Enquiries Unit

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