1904 



FORESTRY AND IRRIGATION 



467 



SCENE IN SAME 



FOREST ONE WEEK LATFCR, SHOWING TOPPINGS 

 PERFECT FIRE TRAP. 



LEFT AFTER CUTTING: A 



has not been burned for about twenty- 

 five years. 



On the other hand, the San Antonio 

 River basin is contiguous, heading in 

 the San Antonio Mountains, running 

 south, thus receiving the precipitation 

 from the south, east, and west slopes. 

 In this area I found that perhaps one- 

 half of the entire area had been burned 

 within the past fifteen years, while the 

 balance of the area showed little signs 

 of fire. Notably in Bear Creek, with a 

 drainage area of about seven square 

 miles, the timber and chaparral growth 

 was remarkably fine and the humus 

 cover very good. There were no evi- 

 dences of a quick run-off in the way of 

 debris and scarred trees and but little 

 variation in the stream flow during the 

 entire summer. These two watersheds, 

 if they had been cared for the same 

 or, in other words, if the fires had been 

 kept out of each, there is no reason why 

 the minimum flow should not have been 

 exactly the same per area. The geo- 

 logical formation of one is identical with 

 that of the other, and in point of geo- 

 graphical position the San Gabriel would 



have the advantage, because it takes all 

 of the north and west drainage of Mt. 

 San Antonio, which has an elevation of 

 10,500 feet, on which the snow would 

 melt very slowly and the run-off would 

 be much more deliberate. 



Now, as -to the benefit of a stream 

 cover. A few years ago I was with 

 Mr. Joseph Lippincott and another en- 

 gineer in the country drained by the 

 San Gabriel, at which time we trav- 

 ersed all of its branches. They were 

 making scientific measurements, and I 

 was studying particularly the effect of 

 forest cover on run-off. Mr. Lippin- 

 cott, at my request, made measurements 

 of the water at the intersection of the 

 West Fork and at a point four miles 

 up the river. This portion of the river 

 and the seepage beds on either side were 

 well covered with willow, alder, and 

 other trees, so that the wind and sun 

 rarely reached the water. Their meas- 

 urements showed an increase of 38 

 miner's inches of water in the four 

 miles, showing the great advantage of 

 tree protection to the water flow. Above 

 this point there is a stretch of six miles, 



