68 



WATER SUPPLY 



after filtering through the gravel and sand. The deep- 

 est of these galleries is 180 feet below the river. The 

 water is pumped from the galleries into storage res- 

 ervoirs. 



About twenty-five years ago it was' observed that 

 the Los Angeles River would not long be able to sup- 



all the storage reservoirs and basins is 38,124 million 

 gallons. From the basins within the city the water is 

 distributed to the consumer through 3,300 miles of 

 water mains. Many pumping stations are maintained 

 to supply adequate pressure to the many levels with- 

 in the city. 



CHART SHOWINODE ATM-RAT t ' B* ST. LOa 



"" PCH 



FOR [AULloiSEAaES 



:DATE5 



Sr/H 



WTAKE 



CHAIN OF HOCKS INTAKE 



| "-CHICASO DRAINAGE: CANAL OPENED 



: ----Ur 



Courtesy St. Louis Dipt, of Put/lie Utility 



FIG. 107. GRAPH SHOWING DECREASE OF DEATH RATE IN ST. LOUIS 



ply the demands of the rapidly growing city. After 

 careful surveys had been made, the high Sierra Ne- 

 vada mountain area was tapped by a 250-mile conduit 

 which was completed in 1913 at a cost of $24,500,000. 



From a point high up in the Owens Valley at the 

 foot of Mount Whitney, the highest point in the 

 United States, the waters of the Owens River are 

 diverted 1 by the aqueduct and carried over the foot- 

 hills of the Sierras, across the Mojave Desert and into 

 Los Angeles. This aqueduct passes through 142 sepa- 

 rate tunnels which total 53 miles in length. There are 

 also twelve miles of inverted steel siphon, twenty- 

 four miles of open, unlined conduit, thirty-nine miles 

 of open cement-lined conduit, and ninety-seven miles 

 of covered conduit. 



Water from the Los Angeles aqueduct empties 

 into twenty-eight storage reservoirs along its route 

 and more than a dozen storage basins within the 

 limits of the city. The combined storage capacity of 



Since the water for this great system is supplied 

 by melting snows and glaciers far away from the pos- 

 sibilities of pollution, 2 little has to be done to it to 

 make it ready for use. Some problems are created by 

 the growth of certain kinds of plant life in the reser- 

 voirs, but these are taken care of by adding copper sul- 

 phate to the water and covering the storage basins. 

 The water is aerated to provide oxygen after its long 

 journey from the mountains. Sterilization with chlo- 

 rine is also used to kill any bacteria which may have 

 got into the water. So high is the quality of Los An- 

 geles water that there has not been a single case of 

 water-borne disease in the city since 1902. 



The intake of the Los Angeles aqueduct is at an 

 elevation of 3,800 feet above sea level and it delivers 

 water 700 feet above sea level. Thus in its journey 

 from the mountains the water drops 3,100 feet. This 

 provides opportunity for water-power development 

 which has been taken advantage of by the city. Along 



1 Diverted, turned from the course. 



" Pollution, contamination; impurity; uncleanness. 



