This site offers a bit more info about the sculpture:

“The Awakening” is a five part cast aluminum sculpture created by J. Seward Johnson, Jr. for the 1980 International Sculpture Exhibition and Conference.  Placed in conjunction with the National Park Service, the “giant” is situated on the grounds of Haines Point and the banks of the Potomac River.

It's a cool little quirk of Washington, but then, there are lots of those.