1. Introduction: BackgroundHigh Speed ​​2 (HS2) is a proposed high-speed rail between London and the West Midlands. The project was launched in January 2009 by a company set up by the government to consider building a high-speed railway in the UK. This train will be able to travel up to 400 km/h by 2020. High-speed trains have been successfully introduced in countries such as Germany, France and Spain (hs2, 2011). Building the high-speed railway would reduce journey times from London to Birmingham to 49 minutes and from London to Manchester and Leeds to 80 minutes. According to the government, British Railways is struggling to cope with the huge increase in passenger numbers that British Railways has experienced in recent years (dft, 2011). High-speed railways need straight lines to maintain speed. According to the government, there are no viable high-speed rail lines between London and the West Midlands that do not, at some point, pass through the Chilterns. However, they claim the train will make full use of the tunnels through the Chilterns to minimize impacts (dft, 2011). However, as we will see in the next section, full use of the tunnels does not mean that it would not have environmental impacts on the Chilterns. There are several aspects to classify its environmental impact on the Chilterns: Biodiversity and ecosystem, noise pollution, carbon emissions and structural landscape (wendoverhs2, 2011). Ministers must make a decision to continue this project, which is currently very controversial.2. BoundaryThe objective of this assessment is to describe the nature of the proposed high-speed railway and its environmental impact on the C...... middle of document ......0111: About the Chilterns. Available: http://www.chilternsaonb.org/about-chilterns.html (Accessed: 28 November 2011).- The Chilterns, 20112: Chalk Streams. Available: http://www.chilternsaonb.org/about-chilterns/chalk-streams.html (Accessed: 28 November 2011).- The Chilterns, 20113: Chilterns AONB Environmental Impact Statement. Available: http://www.chilternsaonb.org/uploads/files/high_speed_2/statement-of-environmental-impact-on-the-chilterns-aonb.pdf- The Chiltern Society, 2011: Concerns arising from geology and The hydrology of the soil underlying high-speed roads (HS2) across the Chilterns. Available: http://www.chilternsociety.org.uk/hs2/paper02.php (Accessed: 1 December 2011). - Wendoverhs2, 2011: High Speed ​​Rail Briefing Number 1. Available: http://www.wendoverhs2.org/documents/WHS2_environment_090111.pdf (Accessed November 26 2011).