BOULDER CANYON PROJECT — NELSON 435 



deficiency bill, making $10,660,000 available for commencing construc- 

 tion of a clam at Boulder or Black Canyon. A board of consulting 

 engineers reviewed the attributes of the two sites and agreed with the 

 engineers of the Bureau of Reclamation that the location in Black 

 Canyon should be adopted. The principal reasons for placing the 

 dam there were that geologic conditions were better, the depth to bed- 

 rock was less, and a dam of smaller dimensions would provide the 

 same reservoir capacity. Furthermore, the distance to power markets 

 was not so great, and transportation facilities to the project could be 

 provided at less cost. 



Fundamentally, the problem presented to the engineer in order to 

 gain control of the Colorado was the placing of a high barrier across 

 the stream which would create a storage basin of sufficient magnitude 

 to stop the river floods, store the spring run-off for all-year utilization, 

 and provide a huge silt pocket. This latter feature was required to 

 be of a type that would not interfere with the production of power or 

 destroy the efficiency of the reservoir. The power plant was also 

 required to be constructed of a capacity adequate to pay all costs of 

 construction from the sales of electrical energy produced by the 

 generators. 



After much study, it was determined that these requirements 

 could be most successfully and efficiently fulfilled by building the 

 dam to store 30,500,000 acre-feet of water and erecting a power- 

 house immediately downstream of 1,835,000-horsepower capacity. 

 Protection of the dam and powerhouse from reservoir overflow would 

 be provided by two spillways, whose outlets would be through tun- 

 nels around the dam, and normal regulation of the reservoir and 

 the furnishing of water to the powerhouse turbines would be secured 

 by four penstock and outlet systems. Each of these latter systems 

 would consist of an intake tower equipped with two gates and lo- 

 cated in the reservoir immediately upstream from the dam, and a 

 system of steel pipes in tunnels leading from the tower base to the 

 power plant or past the powerhouse to needle valves in outlet works. 



Building a dam in Black Canyon offered so many obstacles that 

 many claimed the project was not feasible, and that, in fact, its con- 

 struction could not be accomplished. A few of their arguments were 

 that the geologic conditions at the canyon were not right for so large 

 a dam ; transportation across deserts and down 800 feet into the can- 

 yon was too difficult for the moving of millions of tons of materials 

 that must be placed in construction; the site was in the middle of 

 the desert where men could not work in summer, owing to the ex- 

 treme heat; no contracting company would risk bidding on so large 

 a job where building conditions were so difficult; the river could not 

 be controlled while the dam was being built ; a dam of the size pro- 



36923—36 29 



