Website:
http://www.usbr.gov/dataweb/dams/mt00571.htm

Description:
Gibson Dam is a 199-foot tall concrete arch, and was the first dam in the world designed using the trial-load method of analysis. Gibson Dam is the primary feature of the Sun River Project which supplies water for irrigation of more than 90,000 acres of land along the Sun River. (http://www.usbr.gov/museumproperty/art/magafan2.html)