50 THE J/lIf/GA Tl OA r A G A'. 



afford thin lining and cannot spend anything on making the foundation 

 solid with concrete. And you cannot make the lining thick enough 

 as can be done with reservoirs for city supply. Asphaltum may be 

 laid against earth if on much of a slope but considerable care, that I 

 have no room to describe here, must be used. It is probable that 

 ordinary street surfacing washed with crude oil until leakage stopped 

 would be the most effective form for the money. 



The subject of procuring water is so large that I have to confine 

 myself to the reservoir branch of it in which I understand you are 

 mainly interested. The last two years have proved our underground 

 reservoirs the most valuable we have and thrown more light on 

 water th in the preceding twenty. It is not possible to make any 

 estimates of their capacity or yielding power as we can of reservoirs 

 above ground, but it is almost as essential to do so and we should 

 try to approximate it as nearly as possible. 



There is absolutely no ground for the belief that thore are any 

 large underground lakes or streams as many water experts are 

 claiming to locate, or that they come from the Rocky Mountains or 

 the Sierra Nevada or from any where but our own locraA watersheds. 

 It is comfortable and gratifying to our pride to think so but not wise. 

 Our danger is in thinking we have below ground an inexhaustible 

 supply and expanding our orchards and vineyards aud alfafla fields 

 too much on the strength of it. To fall back upon when the water 

 above ground falls from a dry season or two the underground water 

 has proved one of our greatest resources. Some of it will undoubt- 

 edly stand any draught that is likely to be made upon it because the 

 expense of pumping beyond the point of natural flow will be the 

 limit of our ability to drain it. But it is quite as certain that much 

 of it is in mere pockets of gravel filled from some distant source, 

 connected perhaps by a mere thread of gravel or even sand. Once 

 exhausted it may take two or more saasons to fill again. No one c;in 

 tell anything about it. 



\Vhether ihis water is found in vast beds of gravel hundreds of 

 feet deep as in San Bernardino Valley, or in so many acres of shallow 

 swamp or meadow land as in parts of Yucaipe, it is in every case a 

 reservoir. The dam is friction instead of masonry, but it is none the 

 less a reservoir and if the gate is kept open too Ipng or too wide the 

 result will be same. 



It is not at all necessary to run to the Rocky Mountains to 

 account for the stores of water we have found below. The grip of 

 gravel on water is like that of a sponge in most cases, while that of 

 sand is still tighter. The waste water of flood winters is great 

 enough to accourt for all the accumulation there is in the great 

 storage basins of gravel and sand, because we must not forget that 

 they have really just been tapped. In some cases, as in San Ber- 

 nardino Valley, the supply is to some extent kapt up during the. 



