10 NATIONAL FOREST MANUAL. 



unit, 



any other miscellaneous structures used in connection with said unit 

 or any part thereof, and all lands the occupancy and use of which 

 are necessary or appropriate in the development of power in said 

 unit. 



" Project works " means the physical structures of a power project. 



" Construction of the project works " means the actual construc- 

 tion of dams, water conduits, power houses, transmission lines, or 

 some permanent structure necessary to the operation of the complete 

 power project, and does not include surveys or the building of roads 

 and trails, or the clearing of reservoir sites or other lands to be occu- 

 pied, or the performance of any work preliminary to the actual con- 

 struction of the permanent project works. 



" Operation period " means the period covered by final permit 

 subsequent to the actual beginning of operation. 



44 Survey-construction period " means the period covered by pre- 

 liminary and final permits prior to the operation period. 



44 Nominal stream flow " means the sum of (a) the flow determined 

 by averaging the values estimated for the natural mean flow for the 

 two-month (calendar) minimum-flow period in each successive five- 

 year period or major fraction thereof, and (b) the stream flow made 

 available from storage not by the project works. 



44 Load factor " means the ratio of average power output to maxi- 

 mum power output. 



44 Total capacity of the power site " means the continued product 

 of (1) the factor 0.08 ;* (2) the average effective head, in feet; (3) 

 the stream flow estimated to be available at the intake (in second-feet 

 and in amount not to exceed the maximum hydraulic capacity of the 

 project works considered as the sum of (a) the nominal stream flow 

 and (b) stream flow made available from storage by project works; 

 and (4) a factor not less than the average load factor of the power 

 system, representing the degree of practicable utilization of the 

 stream flow estimated to be available, and based on the extent of 

 fore-bay storage and the load factor of the power system. 



44 Rental capacity of the power site " means the capacity on which 

 the rental charges are based. Unless otherwise ordered by the Secre- 

 tary, it will be determined by making the following deductions from 

 the total capacity of the power site. 



(a) Whenever power projects include water- conduit sites not 

 wholly on National Forest lands a deduction will be made from that 

 part of the total capacity of the power site which is due to the use 

 of the nominal stream flow. This deduction will be, in per cent, the 

 sum of (1) the product of the proportion of the average effective 

 head obtained from the dam by the per cent of submerged lands 

 below the flow line fixed by the average effective head that are not 

 Rational Forest lands, and (2) the product of the proportion of the 

 average effective head obtained from the water conduit (from intake 

 to tail-race outlet) by the per cent of the length of said conduit which 

 is not located on National Forest lands. 



(b) Whenever power projects include reservoir sites not wholly 

 on National Forest lands a deduction will be made from that part 

 of the total capacity of the power site which is due to the use of 

 stream flow made available from storage by the project works. This 



1 The factor 0.08 represents the horsepower at 70 per cent efficiency of a second-foot 

 of water falling through a head of 1 foot. 



