146 



MULTIPLE PURPOSE RIVER DEVELOPMENT 



High Dam and 117,000 from the three dams), and from flood 

 control and navigation benefits on the Lower Snake and lower 

 reaches of the Columbia. These benefits, or their annual average 

 monetary equivalents, are detailed in Table 21. Total benefits of 

 $42.8 million annually available from development by means of the 

 High Dam would be approximately $12 million more than the 

 annual average available from development of the three-dam 

 alternative. 



The more efficient scheme of development is revealed by compar- 

 ing the added benefits and the added costs of the High Dam over 

 the three-dam alternative. The ratio of incremental benefits to 



TABLE 21. Average Annual Value of Project Services of Hells Canyon 



High Dam and Three Low Dams, Assuming Public Development 



Item High Dam Three Low Dams 



(kilowatts) (kilowatts) 



Prime power ": 



At site 647,000 585,000 



Downstream 314,000 117,000 



Total 961,000 702,000 



($ thousand) ($ thousand) 



Value of prime power at $41.58 per 

 kw.": 



At site 26,902 24.324 



Downstream 13,056 4,863 



Increment to system 39,958 29,187 



Value of flood control benefits "= 2,600 1,400 



Value of navigation benefits "^ 250 100 



Total average annual value of project 



services 42,808 30,687 



Increment of average annual benefits 



of High Dam over three low dams 12,121 



"FPC, Staff Brief, op. cit.. Appendix A, pp. 14, 17; Appendix B, p. 10. 

 Assumes depletion flows associated with 366,650 additional acres to be irrigated, 

 a critical period of thirty-two to thirty-four months, and operation of the 

 facilities under conditions of hydraulic integration. 



" Ibid., p. 14; FPC, Decision, op. cit., p. 47. 



" Exhibits, op. cit.. No. 372. 



