CHAPTER XIV. 89 



Second: The water from the tier of springs in the valley. This 

 ■water is also and exclusively derived from rainfall in the mountains. 



There are in our valley lands between the Sierra and the sea 

 at least two distinct water-bearing districts. One of these is repre- 

 sented by the tier of springs and artesian wells running across the 

 San Gabriel from the Santa Anita to the Marengo ranchos; a second 

 water-bearing strata comes to the surface at Los Angeles and El Monte 

 and a third in the low lands back of Ballona, Long Beach and Newport 

 Landing. 



The Santa Ana water-shed and its off-flow in that valley, has the 

 same general feature. The waters from our artesian water belt and 

 from such springs as those on the Santa Ana, San Gabriel and Los 

 Angeles rivers are derived from subterannean lakes in which seepage 

 water is upheld by strata impervious to water. Sometimes, this sub- 

 terranean water is under pressure and between double lines of im- 

 pervious strata, as in all of the artesian belts and sometimes it is not, 

 ■ns in most of the San Fernando and San Gabriel valleys. 



This water comes from the winter rainfall in the Sierra, which 

 coming out of the mountains into beds of boulders, gravel and long 

 sand wash, sinks down into the soil and by slow percolation and large 

 valley areas of storage, forms the reliable supply of our great second 

 tier springs. These again, with surplus winter flow, store the wide 

 lowland valleys with water available in summer. 



THE RAINFALLS ON THE VALLEYS INSUFFICIENT. 



The rainfall on the valleys themselves cannot furnish this water. 

 The rainfall is inadequate to do it. There Is a subterranean lake Ir 

 each of our large valleys. These are very generally tapped by wells. 

 We have generally learned what this water level is and can now cal- 

 culate just what the depth of a well must be at any point to strike 

 water. This is found by taking the known water level and calculating 

 the higher or lower land surface level above it, where the well is to be 

 dug. If we take these wells in the San Gabriel, above the line of 

 springs toward the mountains, we will find that they run from forty 

 to three hundred feet deep according to the land-level. 



In digging these wells, we find the surface moisture to vary In 

 depth with season and treatment of land. There is always dry soil at 

 all seasons between this surface moisture and the water level. It is 

 therefore clear that the rainfall on the valley and above this lake is 

 not the source of its supply. 



If you go out to the roaring mountain torrents flowing from the 



