780Ci46: United States Geological Survey floating tank and 85-foot circular reservoir.
Title information from "Evaporation from Free Water Surfaces" by Carl Rohwer. See Plate 7A, which also notes that the "wave barrier is visible beneath the water surface at the center roof the reservoir." Two horses in corner of fence on right side of image. Image looking southwest, with the College Farm fields and mountains visible behind the 85-foot circular reservoir in the foreground.