THE IRRIGATION AGE. 



175 



to pay at the rate of $25.00 per acre for the service, 

 or $2.50 per year for each acre of land owned, and the 

 cost of maintenance, which is not to exceed $2.00 per 

 acre. At the end of the ten years the entire plant is 

 to be turned over to the association without charge 

 and in perfect condition. No tract of land owned by 

 any one person exceeding 160 acres is to be admitted 

 to the service a restriction placed by the Government 

 to bar speculators. 



The system is to be supplied with water from 230 



Block on Main Street, Boise. 



wells, which will be divided into twenty-three groups. 

 Of each group nine wells are to be sunk to a depth of 

 sixty feet and one to a depth of 300 feet. The average 

 depth at which a strong underflow of water is found in 

 this vicinity is six and one-half feet, but by sinking 

 the wells to the depths proposed they will also serve 

 as reservoirs and thereby insure reliable service. The 

 area is underlaid with sand and gravel to a great depth, 

 and therefore the sinking of the wells will be no very 

 difficult task. 



Each of the twenty-three groups, comprising ten 

 wells, will be supplied with a pumping station, each 

 arranged so as to be operated independently, and eacli 

 discharging its water into a concrete-lined flume, or 



Residence of H. B.Eastman, Boise. 



surface conduit. There will be a central power station, 

 located about the middle of the line of pumping plants, 

 from which the power will be distributed electrically 

 and independently to operate each plant. The central 

 power station is proposed to develop 750 brake horse- 

 power from gas engines, which will use producer gas 

 lor fuel. The gas engines will be divided into three 

 units each of 250 horsepower, connected directly with 



175-kilowatt, compound wound, direct current gener- 

 ators of 550 volts and 225 r. p. m. At each pumping 

 plant there will be a 25-horsepower motor of ordinary 

 series, connected directly by vertical shafts to centri- 

 fugal pumps, both motors and pumps being provided 

 with automatic oilers. Concrete buildings will house 

 each of the pumping stations and the central power 

 plant. 



St. Alphonsus Hospital, Boise. 



The area to be irrigated, being uplands, or second 

 bottoms, is from thirty to fifty feet above the bed of 

 the Arkansas Eiver, which flows through the district, 

 and on this account it is necessary to carry the water, 

 or a portion of it, for considerable distance to get suffi- 

 cient fall. In fact, about half of the wells will be 

 located on the side of the river opposite the land to be 

 irrigated. A concrete conduit will carry the water from 

 the pumping plants to the ditches, and at the point 



St. Teresa's Academy, Boise. 



where it is to cross the river an inverted siphon of 800 

 feet in length will be constructed also of concrete so 

 as to carry the water beneath the river's bed. The 

 total length of the concrete conduit, from the farther- 

 most well to where it empties in the lead ditch will 

 be 2,400 feet, and the average fall for the distance is 

 two and one-half feet per mile. 



Careful tests of the wells owned in this vicinity by 



St. Luke's Hospital, Boise. 



individuals and of temporary pumping plants show that 

 there need be no fear but that the system will be amply 

 watered. The specific capacity of each square foot of 

 well strainer can be reliably estimated at 0.25 gallons 

 of water per minute. At this rate each well under a 

 ten-foot head sunk to a depth of sixty feet would yield 

 over 400 gallons per minute; or if under a fifteen-foot 

 head, as is proposed, there would be a yield from each 



