83 



water to drain out by gravity from the first thousand feet of the 

 tunnel. A hydro-electric power plant operated by this water 

 was installed in the valley below. The water encountered, in- 

 stead of reaching a maximum of about ten or twelve million 

 gallons per day as was expected, far exceeded this estimate, and 

 as the bore progressed the amount of water increased until large 

 syphons had to be installed to keep the water from driving out 

 the workers. On June 26, 1914, when the north side bore had 

 reached a point about 1700 feet from the surface the water had 

 increased to about forty million gallons per day and the work 

 on the north side had to be stopped on this account. 



Early in November, 1914, the flow began to decrease and this 

 decrease fias continued more or less gradually until on Novem- 

 ber 20, 1915, it reached about eight million gallons daily, which 

 is but two million gallons per day in excess of the former low 

 water flow from the Waiahole springs. This flow measured 

 about the same until January 26, 1916, when the last measure- 

 ment was made. 



In the south end of the tunnel little water was encountered 

 until about March, 1915, when the heading was about ten thou- 

 sand feet in from the portal ; the maximum discharge of about 

 fifteen million gallons was encountered about July 20th, and 

 after that date the flow gradually decreased to about four mil- 

 lion gallons daily about December 11. 



From present indications it is evident that little inflow within 

 the main tunnel is to be expected in addition to the flow of from 

 six to eight million gallons daily, which formerly appeared as the 

 Waiahole springs. 



Principal Features of Project. 



Main Tunnel — Length, 14,567 feet; elevation above sea level, 

 north portal about 750 feet and south portal about 725 feet ; 

 gradient 0.2 per cent, or two in one thousand. Cross section, 

 bottom width 7.0 feet ; maximum depth of water 5.0 feet ; water 

 surface width 8.0 feet. Total depth 7.S feet. Maximum capaci- 

 ty 125 million gallons daily. 



North Side Tunnels — Total length 24,621 feet. Gradient and 

 cross section the same as main tunnel. 



South Side Tunnels, Ditches and Structures — Tunnels have 

 gradient of 1.3 in 1000 and the same cross section as main tunnel. 

 Length 19,211 feet. Open ditches, length 18,580 feet. Liverted 

 syphons, total length, 72-inch and 78-inch diameters, about 4000 

 feet. 



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The work was started in January, 1913, and the water will 

 be turned into the tunnel about May 1, 1916. 



The total cost of the project is said to be about $2,300,000. 



