92 WATER SUPPLY. 



are safe-guarded. Every one here is in favor of forest preservation or 

 the mountains. In the matter of the water absorbing power of our tor- 

 rent cones and washes, we can gain an idea of what such porous chan- 

 nels must do by taking the absorbative power of large rivers generally. 



The Po, a great river of northern Italy, at its junction with the 

 Ticino, has sometimes delivered 19,500 cubic yards per second. This is 

 near its outlet from the mountains or in its upper course. At Ponte 

 Lagoscuro, near Ferrara, pretty well down its course, the measure- 

 ment has never exceeded 6,730 yards. 



The Mississippi, below the mouth of the Ohio, has had a delivery 

 of 52,000 cubic yards per second. This discharge at Baton Rouge, in 

 spite of many important tributaries, was only 46,760 cubic yards. 

 Marsh, who is my authority for this, states that the Rhone and other 

 large rivers, are affected in the same way by absorption of water in 

 their course. 



Southern California everywhere shows how near it is to the line 

 of torrent destructive action. Every stream here has a more or less 

 torrential character. Every mountain canyon has its torrent cone now 

 with the beds of boulders, gravel and sand extending valleywards. 

 There is no true perennial stream from mountain to sea in this sec- 

 tion. 



One has only to take the government contour maps and observe 

 the rise of grade at every canyon outlet due to the deposits of detritus 

 by the streams' torrential action to see the importance of the torrent 

 question. In fact, you do not have to leave Los Angeles City to note 

 this character of action. The river bed has been raising itself and now 

 flows on a sort of ridge between artificial dykes. A great deal of the 

 elegant Southwestern section of the city is lower than the bottom of 

 the river bed. In some places the river bed is over twenty feet above 

 the level of the street grades. 



A torrential stream, like the combination of the Tejunga and San 

 Fernando torrents, that flows out through Los Angeles, is a dangerous 

 thing. A lot of old rotten wooden dykes do not make it safe. In 

 1889 the river broke out of its channel and did a great deal of damage 

 about Nadeau and on the Laguna. It flowed out that time to the East. 

 If it took a break to the west, people would commence to take an 

 interest in forestry in the city of Los Angeles. 



Every year the water-holding power of the water-sheds, the off- 

 flow of which must go through Los Angeles, is diminishing. The city 

 people have an idea that the Southern forests interest the irrigators 



