Without exception, the construction and operation of civil engineering projects have resultant environmental impacts. However, in most cases the projects are essential to the economic and social development of the regions where they are located and for some, their sole purpose is to protect people and goods from natural hazards such as floods and landslides. In general, the media and environmentalists tend to enhance the negative impacts of the projects and very seldom make reference to their positive impacts. In this context, the need for high quality studies and designs is assuming increasing relevance for engineering projects, to ensure solutions with the least negative impacts are selected and subsequently constructed and operated by suitably qualified staff. The role of geotechnics in the optimization of civil engineering projects is therefore as important as is the efficient and early intervention of specialists, and their decisions, on the technical, economic, social, environmental and operational aspects of the works. To illustrate that it is often possible to optimize projects from an environmental point of view, several examples are presented in relation to construction materials, hydraulic developments, linear works (roads, railways, airways, and waterways), underground works, maritime works, bridges and viaducts, and natural and excavation slopes. In each case, emphasis is placed on the environmental concerns that require optimization of the design in order to minimise the negative impacts without diminishing the economic and social benefits of the works.
