THE BOULDER CANYON PROJECT 



By Wkslett R. Nelson 

 Associate Engineer, Boulder Canyon Project 



[With 10 plates] 



From the year 1537, when the caravels of Francisco de UUoa, a 

 lieutenant of Cortez, attempted passage up the Colorado River from 

 the Gulf of California only to be turned back by the river's bore, an 

 unending battle has been waged to bring the Colorado under man's 

 control. 



Born in the melting snows of the Rockies of Colorado and Wyo- 

 ming, and receiving sustenance from tributaries in southwestern 

 States, the river has cut its way for millions of years through all the 

 obstacles raised in its path to the sea. The mile-deep chasm of Grand 

 Canyon, the sheer cuts through mountain ranges at Boulder and Black 

 Canyons, and the delta thrown entirely across the Gulf of California, 

 forming the Imperial Valley, attest the great power of this erosive 

 agent. 



For most of its 1,700-mile journey, the Colorado flows through 

 lands that are incapable of producing crops, owing to insufficient 

 rainfall in the growing season. Summer rains in the lowlands are in 

 the nature of cloudbursts, and in many cases are a detriment rather 

 than an aid, owing to the wearing away of the land. The river's 

 flow is very erratic and difficult to forecast. Heavy rains may cause 

 floods in any month of the year, but high water of 100,000 or 200,000 

 cubic feet per second flow usually occurs in the spring and early sum- 

 mer, and the river is at its low state of 3,000 to 4,000 cubic feet per 

 second from September to February. 



At first the river's conquest was considered in terms of navigation. 

 History reports that Hernando de Alarcon in 1540 conquered the 

 swift running waters at the mouth of the river, where the struggle 

 between Gulf tide and river current defeated de Ulloa, and ascended 

 the river a hundred miles upstream to the present location of Yuma, 

 Ariz. In later years, frontiersmen in search of good hunting, gold, 

 and homes sought to travel downstream on its waters and thus avoid 

 the hazardous and laborious journey overland through cold moun- 

 tain ranges, hot arid desert, or unfriendly Indian country. A few 



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