Photo by ENR/Tom Sawyer The City Hall renovation in New York City includes a fuel cell near the building that will be generating most of the its daily load of electricity. Tricky tunneling work paved the way for the box, which has also attracted controversy. Photo by Tom Sawyer/ENR A trench helps bring in upgraded ConEd electrical feeds before it turns about 30 for a 200-ft run to City Hall, which was part of construction management firm Hill International's plan to build new power lines while working around the archaeological hotspots in lower Manhattan. Related Links: Fuel Cells Finding Their
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.