IRRIGATION IN FIELD AND GARDEN. 



BY PROFESSOR E. J. WICKSON. 



(Reprinted from Farmers' Bulletin No. 138, issued by U. S. Dept. of Agriculture.) 

 TUNNELING FOR WATER. 



Tunneling to intercept water-bearing strata is frequently resorted 

 to. Such tunnels have been aptly called "horizontal wells." In Cali- 

 fornia thousands of them have been carried into hillsides to secure 

 water for irrigation and for domestic uses, both in town and country. 

 Outcropping of water-at the bases of slopes, or at the mouths of de- 

 pressions connecting hillsides, often suggests tunneling. The purpose 

 is to cross the strata inclining toward the tunnel, and any available 

 suggestion as to the dip of the strata in the hill, from seepage or 

 otherwise, is important. 



The writer knows of a case where several tunnels were run into a 

 hillside at different points and none of them yielded in satisfactory 

 amount, though carried several hundred feet into the side of the hill. 

 Afterwards it was noticed that the base of the other side of the hill 

 showed springs, while the side which had been tunneled showed none. 

 The owner on one side lost all his investment in tunneling, while the 

 owner on the other side secured all the water by merely opening 

 springs, because the strata on the hill inclined his way. Tunneling is, 

 therefore, not a sure way to get water, and some horizontal wells may 

 be as dry as some vertical wells. 



Again, there may be a quick rush of water into a tunnel which 

 will drive out the workmen and almost as quickly cease. In such a case 

 a sort of water- pocket or the upper part of a water stratum is pierced 

 and its supply soon drawn off. And yet many tunnels are very satis 1 

 factory and enduring in their flow. One of considerable length is 

 known to the writer, the mouth of which was walled up by the owner, 

 an iron pipe and valve being securely bedded in cement mortar, and 

 the tunnel made to constitute an underground reservoir as well as a 

 source of supply, the water being drawn off as desired for domestic 

 use and for garden irrigation. Drifting and timbering are involved in 

 this line of water development, but they are not easily understood, 

 and skilled workmen are necessary for such construction. 



FLOWING WELLS. 



Flowing wells are largely employed for irrigation in regions where 

 such a supply can be secured. Their cost and availability are quite 

 fully understood in those regions. It must be said, however, that 



