238 GUIDEBOOK OF THE WESTERN UNITED STATES 
up the Colorado as late as 1895. The Southern Pacific Railroad 
reached Yuma from the west on September 29, 1877, and established 
its station on the east bank, south of the mouth of the Gila, where 
there had been a few houses since the time of the Gadsden Purchase, 
in 1854. That place remained the terminus until April 28, 1879, 
when the tracks were completed to Maricopa. In 1880 connection 
with the East was effected. Now Yuma is entirely on the Arizona 
side. 
Yuma and its environs have been greatly benefited by the comple- 
tion of the Yuma irrigation project of the United States Bureau of 
Reclamation. The water is diverted from the Colorado River at 
Laguna Dam, 10 miles northeast of Yuma on the California side, 
begun in 1902, one of the first results of the reclamation act. The 
dam is 4,780 feet long and raises the stream about 10 feet, creating 
a long, narrow lake that provides water for 100,000 acres of irrigable 
land lying partly in Arizona and partly in California. Part of the 
region is the alluvial flat along the river, including the Yuma Indian 
Reservation of 8,000 acres on the California side, and part is on the 
level ‘‘mesa” or terrace extending south from Yuma, onto which the 
water is raised by pumps operated by cheap electric power produced 
near by. 
The mesa division comprises 45,000 acres lying about 80 feet above 
the valley, of which approximately 15 per cent is now being developed, 
with 1,400 acres under cultivation and 934 acres producing in 1930. 
The soil is very sandy, but its deficiency in organic matter is easily 
remedied by the use of fertilizer. The climate is frostless and well 
adapted to citrus and other semitropical fruits, which in 1930 yielded 
a return of $156,265, or nearly $167 an acre. (See pl. 34, B.) About 
two-thirds of the product was grapefruit, of which about 60,000 trees 
were bearing in 1930. It costs from $8,000 to $10,000 to develop a 
10-acre unit. The yield of citrus fruits averages about $50 an acre 
after 4 years, $163 after 6 years, and $350 after 8 years. The 
value of all crops of the Yuma lowlands and mesa in 1928 was 
$5,105,132, or $113 an acre. The total cost of construction of the 
Yuma project has been more than $12,000,000, but this is being 
repaid to the Government by the owners of the land. It amounts to 
$55 to $90 an acre. (U.S. Bureau of Reclamation.) 
An interesting engineering feature of this project is the siphon by 
which part of the water is carried under the Colorado River, an ex- 
pedient necessitated by the difficulty of carrying a canal across the 
Gila River, which empties just above Yuma. The water is brought 
from the Laguna Dam by a canal along the west side of the river; 
__ the siphon is 1,000 feet long and 14 feet in diameter and passes 50 
feet below the bed of the river. The inlet may be seen just north 
of the railr aad bridge. The Colorado River carries a large amount 
