140 Adventures in Scenery 



streams flow back to the valley floor. Porous deposits take up 

 the waters that flow upon them. Many streams on alluvial 

 slopes spread out and sink into the porous soil. Thus irrigation 

 waters are made possible through artesian or pump wells. Irri- 

 gation ditches carry water by gravity from the mountain 

 streams. Lands that are normally arid are rendered productive 

 where water can be supplied, either by gravity canals from 

 streams or from wells either artesian or pumped. 



