Looking upstream before the cofferdams were in; Nevada side on left. Note work boat on Arizona side, carrying dynamite batteries from above dam to dam site. Note on back: "All the blasting Wint observed used a generator, not batteries. Later the power was provided by permanent lines. - James J. Hester, son-in-law of W. A. "Wint" Davis, photog."

Starting to build the cofferdam. Bridge used to dump load after load of rock into the river.

Looking downstream at cofferdam and diversion tunnels.

Cofferdam (upper one), 1/4 - 1/2 mile upstream from Dam site. Dec. 25, 1932. Note on back: ""Electric Marion steam shovel on top of cofferdam. May have used shovel to lay down metal grating. - W. A. Davis.""

Aerial view of canyon basin just before 'drying up'. Workers are preparing to dry up bottom of canyon.

Aerial view of Colorado River drying up after cofferdam was built.

Working at Hoover (Boulder) Dam. The machinery shown include a water pump and power shovel. Note on back: "Not taken by W. A. Davis. That day the river came up and flooded tunnel on Arizona side. This shot shows pumpking the water out with a large sump pump. - James J. Hester, W. A. Davis' son-in-law, 1992."