The soil where the runway will be extended is contaminated with asbestos https://www.asbestoslawpartnership.co.uk/news/26/Asbestos-Locomotive-Works-Railways and heavy metals (including arsenic) from the adjacent land which has housed railway works for many years. A tunnel underneath the runway will be required to access the development site to the north east of the airport site https://www.southamptonairport.com/media/5988/sou-a-vision-for-sustainable-growth.pdf [page 36] . This will necessitate removal of water during construction and forever after. Unless the water is tankered away, it will be pumped into the river Itchen. The Itchen Valley Country Park is a Site of Special Scientific Interest and one of the few UK homes to this rare and protected species: http://www.hampshirebiodiversity.org.uk/pdf/PublishedPlans/SouthernDamselflyjjDTP.pdf .