Civil engineering is one of the most diverse engineering disciplines. Civil engineers are responsible for the planning, design, construction, and operation of the physical structures and facilities essential to the infrastructure of modern society: buildings, highways, water and waste treatment plants, tunnels, airports, harbors, and bridges. The civil engineer is also involved in research and development in a wide variety of physical and natural systems. These include the rebuilding of the nation s infrastructure and forecasting the impact of human activity on the environment with the use of mathematical models.