318 



FORESTRY AND IRRIGATION 



July 



For small pumping plants a single 

 well of the depth indicated above 

 would probably be sufficient, but if 

 good water bearing gravels do not ex- 

 tend to the requisite depth, it would 

 be necessary to increase the number 

 of wells and connect several of them 

 to the pump. 



arrangement of the wells. Two dif- 

 ferent methods will be found avail- 

 able for this purpose. If the amount 

 of water required is not greatly in ex- 

 cess of that which can be supplied by 

 a single tubular well it is often found 

 practicable to construct a large dug 

 well, 6 to 10 feet in diameter, to a 



Fig. 1 Well strainers made of slotted galvanized iron. These strainers are 15 inches in 

 diameter, and ten feet long, provided with 3-16 by 1 1-4 inch hit and miss slots, 

 punched before the steel is galvanized. The strainers shown in the diagram were 

 made of No. 18 wire gage sheet steel. 



distance between WELLS. depth of 5 to io feet below the water 



If it is necessary to construct sev- level > inserting in the bottom of the 



eral wells in order to secure the dug well several feeders of perforated 



amount of water required for an irri- galvanized iron, as described above, 



gation plant, it becomes important to This method has the advantage of per- 



consider the best and most economical mitting the pump that is to recover the 



