The concept of the Southern Expressway was introduced by the Road Development Authority (RDA) and the Ministry of Highways in the late 1980’s as a part of the network of new highways proposed to cater to the increase in transport demand of the country. The University of Moratuwa undertook the Environmental Impact Assessment (EIA) study for a new Southern Highway at the request of the RDA, in 1996, and the EIA report was submitted in early 1997. This is the first volume of this proposed study that was conducted by a team of consultants whose team leader is an EIA specialist with an environmental/civil background.