Civil engineers design, plan, and oversee construction projects. They create, improve, and protect the environment. They plan, design and oversee construction and maintenance of building structures and infrastructure, such as roads, railways, airports, bridges, harbors, dams, irrigation projects, power plants, and water and sewerage systems. They also design and build large structures that can withstand all weather conditions. Generally, civil engineers fall into two types: consulting engineers and contracting engineers. Consultants are responsible for the design work of projects and work predominantly in an office. Contracting engineers work on site, managing the construction. Civil engineers usually work for: construction companies, local authorities, government departments, rail companies, or utility companies. Their responsibilities include: investigating sites, using computer software to develop designs, making complex calculations, and liaising with clients and other professionals. They also are required to resolving design problems, managing budgets, scheduling purchases and deliveries, and ensuring the project runs smoothly.