More than a mile long, the Grand Coulee Dam is the largest concrete structure in the U.S. In the fall of 2011, dam operators agreed to open the spillway just for American Experience. "It was very ...

Water started flowing over an emergency spillway at the ... Unexpected erosion chewed through the main spillway earlier this week, sending chunks of concrete flying and creating a 200-foot-long ...

The Mississippi River is approaching levels that could trigger a full operation for the first time in four years.