The substantial body of empirical research now available on wind farm visual impact (VI), from very credible and impartial teams, shows a consistent and essentially linear relationship between turbine height, distance and wind farm VI. For any degree of VI (such as the zone of visual influence, or threshold for visual dominance), if turbine height is doubled, the distance threshold for that degree of impact also typically doubles.
The research based distances for thresholds for key levels of VI are many times larger than thresholds proposed by the NSW Department of Planning and Environment in its draft VI Assessment Bulletin. The Department’s proposed thresholds are repudiated by the consistent research findings.
The research also identifies a number of other ways in which wind farm VI assessment practices accepted by NSW planning agencies are defective, in particular relating to the neglected importance of blade movement for VI, the fact that photomontages tend systematically to underestimate VI, and the assessment frameworks commonly used are too simplistic to describe real world experience.
The NSW Government has a responsibility to reassess its draft VI Assessment Bulletin explicitly in the context of the published research and produce proposals which it can intellectually justify in the context of that research – which at present it cannot do.
Image Source: The Land