Inquiry QuestionActivities Visual Evidence Photo 1: Elephant Butte Dam Under Construction, 1915 (National Archives and Records Administration; photographer identified as R. G.) Questions for Photo 1 1. Look carefully at Photo 1.  Find the two groups of tall triangular towers on either side of the river.  These were the anchors for three cable systems used to transport concrete and other construction materials and equipment across the river and down to the dam site.  Can you find items suspended from the cables?  Why do you think Reclamation used this kind of system?  How would they have moved materials down to the dam site if they hadn’t used the cable system? 2. See if you can find the two construction camps.  The lower camp was along the river at the left edge of the photo.  The upper camp was between the dam and Elephant Butte (the mountain in the background).  What kinds of buildings were located there (refer to Reading 3, if necessary)?  Note the “batch plant” used to make the concrete for the dam, visible near the end of the dam at the right side of the photo.  Why do you think Reclamation had to build camps like these? 3. The reservoir behind the dam is already filling with water, even though the dam is not yet complete.  Can you find the outlet where water is flowing out at the base of the dam?  Why do you think Reclamation engineers allowed that water to continue to flow down the river? 4. Elephant Butte Dam is a concrete gravity dam 301 feet high and 1,674 feet long.  According to the Fourteenth Annual Report, published in 1915, Elephant Butte was the “largest structure yet undertaken by the Reclamation Service.” 7  Does it look small in the photograph?  Sometimes the only way to get a sense of how big something really is is to compare it to something you know.  A football field is 360 feet long.  How many fields long and high is the dam?  The dam contains 618,785 cubic yards of concrete.  How big is a cubic yard?  Can you calculate how many cubic yards would fit into your classroom?  How many classrooms would you have to stack up to be as big as the dam?  7  Fourteenth Annual Report of the Reclamation Service, 1914-1915 (Washington, DC:  Government Printing Office, 1915), p. 10. Click for a larger version of Photo 1.