Neil Elliot, principal landscape planner, LUC, considers how to make cumulative assessment more effective.
It has been a long-standing requirement for a Landscape and Visual Impact Assessment (LVIA) supporting a planning application, for example for a large scale wind farm, to include a cumulative LVIA (CLVIA).
Smaller wind energy developments and other forms of development are required to consider cumulative effects too. Undertaking a CLVIA for a large wind farm typically involves the consideration of other wind farms that are operational, under construction, consented or undetermined within a large study area.
A starting point of 60km radius is typical but this is usually reduced to 30km. Increasingly, local planning authorities (LPAs) are asking for schemes at scoping stage, before a valid planning application is made, to also be included. In certain parts of the country, this can result in a very long list of wind farms which need to be considered.
When considering cumulative effects these are typically considered in terms of ‘additional effects’ or ‘total/ combined effects’:
- Additional effects consider the addition of the proposed development to cumulative baseline broken into two scenarios: a cumulative baseline which considers all operational, under construction and consented schemes, and a cumulative baseline which considers the same schemes, and applications that are yet to be determined. The different scenarios are developed to reflect the uncertainty that the undetermined schemes will be built.
- It is important to consider the cumulative context at the early site selection and design stage. If a wind farm is designed as a sensitive extension to an existing scheme, or appears as a distinctly separate wind farm in a landscape which has capacity to absorb a development of this type, it is usually possible to avoid triggering significant ‘additional’ cumulative effects.
However, we have reviewed a large number of CLVIA on behalf of LPAs, some of which are for poorly designed schemes, which quite often make the following argument when assessing additional effects: ‘there are a large number of wind farms here already, so the small incremental change the proposed development represents is unlikely to result in significant cumulative effects.’
An assessment of total and combined effects considers the total cumulative picture, including the proposed development, and can be broken down using similar scenarios. Increasingly, and given the large number of wind farms considered in a typical CLVIA, the findings of the total cumulative assessment often boil down to the following argument: ‘there are a large number of wind farms here (including the development) which is likely to result in significant total cumulative effects. However, the proposed development is not considered to be the wind farm which has tipped the balance into ‘total’ cumulative effects being considered significant.’
Ironically, significant additional and total cumulative effects tend not to be triggered in landscapes where there are large gaps between the proposed wind farm and other schemes. However, following this type of spatial planning through to its conclusion would likely increase the overall influence of wind farms across the landscape, whereas planning should aim to cluster wind farms into less sensitive areas.
While this presents a simplistic view, and each development always throws up its own peculiarities, these arguments or similar themes of them are often used in the findings of CLVIA. This begs the question of whether cumulative assessment still helping to guide new wind farms to the best sites and help the LPA in determining applications?
So where do we go next? Increasingly LPAs are turning to strategic cumulative spatial planning.
Strategic cumulative spatial planning
There is a growing understanding that spatial planning can be used as tool in managing cumulative landscape and visual impacts. For more than a decade, authorities have used information from landscape character assessments to define areas of search for wind farm developments. These assessments tend to be based on an analysis of the sensitivity of landscapes’ key characteristics to development, taking account of factors such as scale and visibility.
More recently, the approach has been developed to consider cumulative issues, with potential, for example, to explore the likely effects of different development scenarios. This is in turn prompting a recognition that cumulative impacts are not always something to be avoided, and that there can be benefits in concentrating development in landscapes with lower sensitivity, particularly where this helps protect more sensitive areas.
The next step is to work with wind energy developers to ensure that neighbouring schemes read coherently in the landscape with similar design strategies, and where possible turbine types. This may reflect the importance of strategic gaps between schemes or groups of schemes, and the way that people experience development, for example while travelling along a road.
In conclusion, to help cumulative assessment become a more helpful tool, we would suggest that:
- the scope of all CLVIAs should be more tightly defined, starting with such a large study area involves collating lots of information on cumulative schemes which are unlikely to ever influence the decision making process;
- more thought should be given to non-operational schemes included in the CLVIA through consultation with the LPA. Including all within a certain radius is not always helpful as some schemes have been in planning or consented for a long time and are unlikely to ever get built; and
- to meet renewable energy targets, certain landscapes will have to undergo significant change. In areas where strategic cumulative spatial planning has identified further scope for development, the need for complex cumulative assessments should be carefully considered. Strategic assessment of cumulative issues can help guide development to the best locations. In this way, cumulative effects can be minimised on sensitive landscapes, but accepted in other landscapes where negative effects are less likely.
