WATER 



193 



at the canyon mouths automatically record the stream flow while reservoirs 

 catch the eroded material; recording gages strategically placed measure the 

 rainfall intensity; and, distributed over the watersheds, more than 100 

 standard gages serve to secure for each storm the most accurate measure of 

 precipitation ever attempted in a mountain area." 



Established in 1931, and set up to run as a 50-year experiment, this forest 

 already has evidence to indicate that burned mountainsides can send down 

 20 times as much floodwater and 1,000 times as much silt and rubble as 

 unburned mountainsides, properly covered. Ordinarily, research foresters 

 do not like to announce tentative findings; they prefer to wait and verify. But 

 the evidence at hand is plain, the situation is crucial, and every year brings 

 further verification. 



Fire, Then Flood; it happens again and again, and the demolition of 

 recreational and all other living values is evident. In the same part of 

 California, repeated fires over a number of years had a devastating effect on 

 the soil-binding cover in the Tujunga Canyon. A flood burst down this 

 canyon on March 2, 1938, and wiped out summer homes, built on both pri- 

 vate land there and on national forest land under special permit, by the 

 score. This demolition was especially distressing as many of these mountain 

 cabins, put up in flush times as week-end places, were being occupied full 

 time by families down on their luck. The water wiped them out. It wiped 

 out roads, camp sites, resorts. It bit off steel bridges as a man might bite a 

 doughnut. Recreation has been, in large part, forced out of this and other 

 accessible "front canyons" now, because of the debris and because, with 

 cover returning but slowly, there may be a recurrence of smashing floods. 



