U.S. Navy Petty Officer (Engineer's Aide) 3rd Class Irwin Tan, a surveyor with Naval Mobile Construction Battalion 133, takes notes while surveying the banks and water line of the Helmand River in southern Helmand province, Afghanistan, Feb. 11, 2013. Tan and Engineer's Aide 3rd Class Mark Monton, also a land surveyor, worked with engineers from Regional Support Command-Southwest, NATO Training Mission-Afghanistan, to plot the river's course and depth for the sites that might be used by the Afghan Border Police in the area. (U.S. Army photo by Bill Putnam/Released)