1906 



FORESTRY AND IRRIGATION 



319 



water to be submerged in tbe water of 

 the well. A well of this sort is shown 

 in Fig. 2. 



In order to sink a dug well the 

 proper distance below the water level 

 it is necessary to construct a wooden, 

 brick, or concrete crib that will sink 

 as the material is removed from its in- 

 terior. The crib of the well shown in 

 Fig. 2 is made of wood, and is made 

 larger at the lower than at the upper 

 end to facilitate sinking. 



Another method of recovering a 

 large quantity of water is to sink a 

 battery of wells and connect them by 

 suction pipe to the pump. This method 

 is adapted to secure a larger supply 

 than the method just mentioned. Three 

 or four, or more wells can be arranged 

 in a straight line, 20 to 30 feet apart, 

 and connected to a pump placed near 

 the center of the row of wells. In the 

 diagram (Fig. 3) will be found an 

 arrangement suitable for a battery of 

 eight to twelve wells. These wells 

 are arranged in pairs, close together, 

 each pair of wells being 40 to 60 

 feet from the next pair on the same 

 suction line. The object of placing 

 the wells close together in pairs is 

 for the purpose of removing a large 

 amount of the fine sand from the wa- 

 ter-bearing gravel. This can be done 

 in gravels like those found in the 

 Western valleys by pumping vigor- 

 ously from one of the pair of wells, 

 and at the same time running clear 

 water into the neighboring well. By 

 this means it should be possible to 

 clear out all the fine material between 

 the two wells. If the water-bearing 

 gravels are of the kind usually found 

 in the river valleys of the Western 

 prairies, a pumping plant can be con- 

 structed sufficiently large to supply 

 from 2,500 to 3,500 gallons of water 

 per minute without lowering the wa- 

 ter more than 10 feet. Pumping plants 

 of greater capacity than this will 

 usually not be profitable. A large 

 number of moderate sized plants is 

 more desirable than a few large ones. 



KIND OF PUMP. 



Probably the most satisfactory 

 pump for use in irrigation is the cen- 



trifugal pump. However, there are 

 many kinds of small centrifugal 

 pumps. It does not pay to purchase 

 any but the very best machinery for 

 the pumping of water, as poorly de- 

 signed machinery soon proves too ex- 

 pensive. The various kinds of pumps 

 differ greatly in this respect. The cen- 

 trifugal pump used by the irrigator 

 should be of the enclosed runner type, 

 provided with self-oiling bearings of 

 the oil ring type. There are several 

 excellent makes of centrifugal pumps 

 on the market, and any of them will do 

 good work if the size and design of 

 the pump fit the conditions under 

 which it must work. The maker of 

 the pump should have full information 

 of all the conditions under which the 

 pump is to be installed. These condi- 

 tions should include the distance that 

 the pump must discharge the water 

 above its outlet ; also the amount of 

 suction or the distance the water must 

 be lifted below the pump inlet. The 

 following points are important to those 

 about to install pumping plants : 



1. The efficiency of the centrifugal 

 pump under actual working conditions 

 is higher for the large size pumps 

 than for the small size. Pumps hav- 

 ing less than 3 inches diameter dis- 

 charge pipe will show a low efficiency. 



2. A centrifugal pump will work 

 better and be more efficient if the suc- 

 tion pipe is as short as possible, rela- 

 tive to the length of the discharge 

 pipe. On this account the pump should 

 be placed as near the level of the water 

 as the securing of a good foundation 

 will permit. 



3. If the pump is to be driven by 

 means of a belt, it should be provided 

 with a large pulley. The pulley usually 

 supplied with the pumps is so small 

 that a great amount of slipping takes 

 place between the belt and the pulley, 

 and the efficiency of the pump is 

 greatly decreased. Of course it is 

 necessary to secure the proper propor- 

 tion between the size of driving and 

 driven pulleys, but both should be 

 larger than are usually furnished with 

 pumps and engines. 



4. The suction pipe on the pump 

 and the discharge pipe should be large. 



