Chapter 1 – Executive summary
Study context
In January 2023, South Oxfordshire and Vale of White Horse District Councils commissioned LUC to produce landscape evidence contributing to the Joint Local Plan that will guide development in the districts to 2041.
The first requirement of this landscape evidence is the production of a new dark skies / light impact assessment which will inform the other elements of the updated landscape evidence. This evidence will identify the darkest areas of the districts which need the strongest protection from light pollution. The evidence also supports an understanding of the levels of light pollution in other areas in the districts to prevent it from worsening.
What is the aim of this study?
This assessment was commissioned out of recognition of the importance of minimising light pollution to reduce the impact on the environment, people and landscapes in South Oxfordshire and Vale of White Horse Districts, and to preserve the dark skies quality of the districts.
This study involved the production of:
- A map showing dark skies and sky glow in South Oxfordshire and Vale of White Horse using satellite data.
- A set of key findings and statistics for the two local authorities and the National Landscapes (formerly known as Areas of Outstanding Natural Beauty or AONBs).
- An evidence-based framework of environmental lighting zones.
The GIS outputs from this study are hosted in an interactive map in the Results section of this digital report.
This report provides an overview of the relevant legislative and policy context. It details the method used to create the dark skies map and presents the headline figures and statistics extracted from the map. Finally, it describes the process of identifying Environmental Zones in the districts.
Future work will be undertaken to develop supporting guidance for the use of the dark skies mapping when considering lighting proposals.
Overview of key findings
The resultant dark skies and light pollution map is shown in the Results section of this digital report. Headline statistics include:
- 6% of South Oxfordshire and Vale of White Horse falls within the darkest sky category (<0.25 NanoWatts/cm2/sr).
- Only 0.3% of the study areas falls within the second brightest category (16-32 NanoWatts/cm2/sr), and none of the study area falls in the brightest (>32 NanoWatts/cm2/sr).
- Both districts have a similar profile across the brightness categories, with South Oxfordshire having a higher percentage of land falling within darker categories.
- The National Landscapes experience little sky glow with 91.7% of Chilterns and 90.1% of North Wessex Downs falling in the two darkest categories (<0.5 NanoWatts/cm2/sr).
Using the Institute of Lighting Professionals (ILP) framework for categorising Environmental Zones [See reference [i]], the two districts have been categorised into the following Environmental Zones based on the brightness data on the dark skies map:
- E1 (Natural dark zone);
- E2 (Rural low district brightness zone);
- E3 (Suburban medium district brightness zone); and
- E4 (Urban high district brightness zone).
Future work will produce guidance which shows how lighting development proposals could be considered in relation to their impacts on dark skies and identifies general principles that can be put in place to protect and enhance dark skies as well as reduce and mitigate light pollution.
[i] Institution of Lighting Professionals (2021) ‘GN01/21 Guidance Notes for the Reduction of Obtrusive Light’ – https://theilp.org.uk/publication/guidance-note-1-for-the-reduction-of-obtrusive-light-2021/