It appears that 14 miles of 120-year-old sand-and-grass dike near Portage, Wis., has survived the flood-swollen Wisconsin River’s recent rise to a record-level 20.6-ft, or more than 3 ft above flood level. With the Wisconsin River&rsquos water level now dropping at about an inch an hour, the series of dikes, built by farmers in the 1890s and now maintained by the Wisconsin Dept. of Natural Resources, appears to be essentially intact, according to the DNR. “The river has dropped to 18.7 ft this morning, and is going down at about an inch per hour,” DNR spokesman Greg Matthews said Sept.
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.