198 



THE AUEIFEROUS GKAVELS OF THE SIERRA NEVADA. 



per day. # Of the reservoirs of this company the most important is French 

 Lake, which was originally a mountain lake of great depth, and which has been 

 increased in size by means of a granite dam, sixty-eight and a half feet high 

 and 250 long, giving a reservoir of 337.32 acres' surface with a capacity of 



661,000,000 cubic feet. The Faucherie reservoir is also a natural lake, raised 

 by a dam to an area of ninety acres and of 58,800,000 cubic feet.f 



Besides the French and Faucherie reservoirs there is another extensive 

 one in the Weaver Lakes, having a capacity of over 100,000,000 cubic feet. 

 Practically, the supply of these reservoirs, if full at the commencement of 

 the season, is counted on as sufficient for five months' run. 



The Milton ditch extends from high up on the Middle Yuba to French 

 Corral, and has a capacity of 2,500 or 3,000 inches. The reservoir of this 

 company, called the Rudyard or English reservoir, is formed by means of 

 three dams, of which the central one is said to be 114 feet high.t It is built 

 of timber crib-work, filled with stone ; and of its character and appearance 

 some idea may be obtained from the accompanying plate, copied from a 

 photograph by Watkins (Plate II). The reservoir is said to hold 535,000,000 



cubic feet of water. 



The North Bloomfield Company has also a complete system of ditches, and 

 a large storage reservoir, called the Bowman reservoir, of which the dam, 

 originally sixty-five feet high, and in 1875 and 1876 raised to eighty-five feet, 

 is intended to be eventually one hundred feet in height, and to hold back 

 about 1,000,000,000 cubic feet of water. 



The actual delivery of water through all the ditches in the divide between 

 the Middle and South Yuba rivers, by the three companies — the Eureka 

 Lake, the Milton, and the North Bloomfield — does not exceed (according to 

 Mr. Hague) 3,000,000 inches annually; while the total possible delivery 

 might be 4,000,000 inches, or, say, 13,500 inches a day for 300 working 

 days in the year.|| At a rough estimate, this amount of water would be 

 sufficient to wash about 100,000 cubic yards of gravel per day. 



* This is about equal to the average discharge of the Ohio Eiver in a minute and a half. 



t The total catchment area of the French and Faucherie reservoirs is, according to the Surveys of Mr. 

 Hamilton Smith, 8,432 acres. The average rain-fall (including snow converted into water) is about sev- 

 enty-eight inches; and of this it is estimated that about three quarters runs into the reservoirs, so that 

 these are supplied with sufficient water to fill them. 



% The height of this darn is given as 131 feet " from the deepest portion of its foundation to its sum- 

 mit," by Mr. Bowie. 



§ This magnificent work is fully described, with a section, in Mr. Bowie's article. 



|| The cost to the Eureka Lake Company of their water may be stated at from i\ to 5f cents per inch, 





