Aviation noise analysis for the Airports Commission to help with their recommendations where to put a new runway in the South East of England.
Background
No new full-length runway has been laid down in the South East of England since the 1940s. With demand growing for over fifty years, it became crucial to provide suitable infrastructure to keep the pace with an expanding aviation market. At the same time, the South East of England is a congested corner of a crowded island, and many factors had to be considered before any decision. In 2012 the independent Airports Commission was set up to assess a wide range of factors including noise, surface transport, employment, air quality, housing and local communities to make recommendations on the new runway. The Environmental Research and Consultancy Department (ERCD) of the United Kingdom Civil Aviation Authority (UK CAA) was contracted by the Airports Commission to calculate forecast noise exposure contours for the three shortlisted proposals (Gatwick Airport 2nd runway, Heathrow Airport north-west runway and Heathrow Airport extended northern runway) to meet long-term capacity demand in the South East of England.
Challenge
The Airports Commission provided an appraisal framework, which set out the requirements for the noise assessment. Along with a range of noise exposure contours, the framework requested modelling of supplementary noise metrics that were not usually calculated at that time. These were the number of noise events exceeding an outdoor maximum noise level (‘Number above’ contours)*.
To gain complete insight into possible implications of the new runway, the Airports Commission required calculations of the monetary cost of noise exposure impacts. This meant to quantify annoyance, sleep disturbance and acute health impacts of noise on people.
The team was tasked to provide noise modelling results for over 70 separate future scenarios, each with multiple metrics. These should include the areas, populations, number of households and noise sensitive amenities within the contours. The calculations had to be accurate as the miscalculations could affect the third runway decision and bring substantial social and economic impact.
Solution
The content of the analysis design had to be impartial, so the client’s specialist traffic forecasting consultancy provided traffic volume data, and the sponsor organisations provided the route design information for each proposal. The ERCD used their expertise to create data to model new, quieter aircraft designs to reflect future scenarios.
The team designed, and quality assured new computational processes to compute the supplementary metrics and developed a methodology that had not been used before to calculate the monetary cost of the impacts of noise exposure.
To ensure accuracy, ERCD established working practices and common modelling assumptions, including average temperature, atmospheric pressures and ground types. Rigorous quality assurance procedures were put in place.
Outcome
ERCD produced results for nearly 350 separate scenarios and noise metrics combinations, requiring over 1,800 different model runs. Monetised impact data were provided, which allowed consideration of economic, operational, social and environmental factors on an equitable basis. Newly developed methodology to quantify acute health impacts of aircraft noise was incorporated in the United Kingdom Department for Transport (UK DfT) WebTAG** assessment guidance. The aviation noise analysis by ERCD was published in 2015 and helped the Airports Commission decide on three proposals for the South East of England’s runway.
*https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/300223/airports-commission-appraisal-framework.pdf,p.59
** Web TAG is the Department for Transport’s suite of guidance on assessing the expected impacts of transport policy proposals and projects.
For more information on our Noise Management advisory services, please contact Sarah.Fox@caa.co.uk
Key Achievements
- Noise contour and numerical results provided for nearly 350 separate scenarios and noise metrics combinations
- New methodology developed and implemented to quantify annoyance, sleep disturbance and acute health impacts of noise
- Monetised noise impact data provided
- Monetisation of health impacts of aircraft noise became part of UK DfT Web TAG
- Aviation noise analysis published, helping with the decision on three proposals for the South East of England’s runway.
