A NATIONAL PLAN FOR AMERICAN FORESTRY 301 



Fortunately the Federal Government had completed the dams in the Ohio 

 River before the great drought of 1930. These dams have maintained full pools 

 from Pittsburgh, Pa., to Cairo, 111., during the entire summer and fall. * * * 

 Many of the larger tributaries * * * have been improved by dams. The 

 water from the pools in these rivers has made it possible for life to exist and 

 business to progress in the Ohio Valley during the driest season of record. 



San Francisco and the immediate vicinity will shortly obtain part of 

 their public water supplies from the Hetch Hetchy Reservoir, 200 

 miles away, built at a cost of $126,500,000. In southern California 

 half the population of the State, concentrated in an area where less 

 than 1 percent of the water of the State is found, now obtains part 

 of its domestic water from the Owens River, 250 miles away, and 

 is preparing to go 200 miles to the Colorado River. Some of the 

 deep wells from which part of the water supply for this area is obtained 

 are being depleted or threatened with invasion by the salt waters of 

 the Pacific Ocean, just as the deep wells of the New Jersey coast 

 resorts are threatened by those of the Atlantic Ocean. The water 

 system by which southern California plans to solve its water problems, 

 primarily of domestic supplies, will cost $350,000,000. 



IRRIGATION 



Irrigating water is the lifeblood of certain communities, such as 

 southern California and the Salt River Valley in which is concen- 

 trated one fifth of the population of Arizona. It is a commodity of 

 enormous importance to 19 States west of the Mississippi River, as is 

 indicated in table 1. Irrigation has been the purpose for which the 

 Federal Government has constructed a number of large reservoirs, 

 such as Elephant Butte in New Mexico and the Arrowrock in Idaho. 



