Five tidal power schemes, the biggest able to generate 5% of U.K. electricity demand, have been shortlisted for the Severn Estuary, the long sea inlet that separates Wales and Cornwall in the southwest of England. The government's inclusion of a full, $30-billion barrage across the estuary has angered environmental groups. Slide Show DECC Fleming Lagoon's design, looping out from one shore, would not obstruct tidal flows as much as a barrage. Having eliminated five schemes, the Dept. of Energy and Climate Change will now consult on its shortlist till April, aiming to select its preferred option early next year. A
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.