Here is another rare example of a slide that Horace captioned. Horace writes, “Coulee Dam during flood. 36 million gallons per minute.” This is surely the flood of 1948, May-June. The torrent damaged the dams underwater flip bucket at its base. The spillway was designed like a ski jump. Water falling down the face of the dam was turned up at the base, dispersing its energy in the process. In 1948, however, the water was too much for the bucket and also river banks downstream all the way to the Pacific. Near Portland, the flood wiped out the town of Vanport. The flood of ’48 indicated the need to work with Canada in flood control of the river upstream from Grand Coulee Dam. The Columbia River Treaty followed in 1960, and Canadian dams too.
