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- " .- 00 -' ~ =- __ :r.' "'" ~_,...;, . ~:::;;;_ ~"";'''''''=\i!~ i~~~-~'~4~,:.~; -~~i~f~~~~~~~~~ ,',. 0/., -~~0~-=-:'~ ~,.\ ,- ,;, -'-OW".- '~~~-- _. '" - I ... :;\r..;t..... ~ ~ -, ..., _..~. _ ~:;:r~. ~ f- ~~~ :~ Solil!lcn! Pncific Railroad lra('k~ ill fhe ImflNial Valley )1'('((' Im.llttyl 011/ during /l1e 1905-06jlood, From there, it drained off through Hardy's Colorado channel and eventually reached the gulf. This was a stroke of good luck because the Colorado could have flowed from Volcano Lake to New River and on into the Imperial Valley again. The fight with the river went on. Levees were built and more money was spent. In 1910, a levee at the cost of $1,000,000 was built along thc west side of the river to put the Colorado in its old channel and keep it there. That levee failed. Other levees were also built, but the continual deposit of sediment at critical places made higher and higher embankments necessary. The costs of combating sediment and floods soon mounted to over $500,000 a year, yet the threat was not stopped. For the Imperial Irrigation Project, it was a continuous, harassing fight, come high or low water. Without greater con- trol over the Colorado, the situation would become intolerable. The Imperial Valley was not the only area along the lower Colorado that suf- fered from the vagaries of the river and its tributaries. The lowlands of the Yuma Valley, where the growing city of Yuma and the Bureau of Reclamation's Yuma Project were located, also felt the punishing effects of both Colorado and Gila River lloods. In 1893, a levee less than a mile long was built along Yuma's eastern boundary at a cost of $10,000 to protect the town from Gila River rampages. Between 1905 and 1908, the Federal Government built a levee south from Yuma to the Mexican border, and from 1909 to 1912, spent $240,000 for levees to safeguard the Yuma Project. Yet, when 200,000 cubic feet of water per second 0.5 million gallons) came down the Gila in January 1916, the levees were breached, water stood 4 feet deep in the streets of Yuma, and project lands were inundated. A Bold Decision Faced with the constant cycles of flood and drought, the people of the Southwest appealed to the Federal Government for help. Reclamation engineers clearly saw the solution to the problem - harness the untamed river and control its flow. This would protect the low-lying valleys against floods and assure a stable year- round water supply. But this would not be an easy task. Uncontrolled and unregulated, the Col- orado had limited value. The yearly flood~drought cycle made large irrigation or power developments uncertain and un- profitable, and the heavy load of silt car- fled by the river made it unsuitable as a municipal water supply. Also, without regulation, the amount of land under cultivation could not be expanded. With the river dammed and under con- trol, the danger of recurring floods and droughts would end. And many potential damsites existed along the river. The Colorado River drainage area is roughly divided into an upper and a lower basin which are about equal in area. This natural geographical division was used to simplify negotiations over the river's water. The "upper basin," it was agreed, should include the drainage area above Lees Ferry, a point one mile downstream from the mOllth of the Paria River in northern Arizona. The "lower basin" would include all the drainage area below Lees Ferry. In their search for a location to build a dam that could protect the lower river from flooding and store enough water to minimize droughts, Reclamation and Geological Survey engineers investigated 70 sites throughout the Colorado River Basin. Upper basin sites considered the most suitable were: the Flaming Gorge site on the Green River in northern Utah, with 4,000,000 acre-feet in potential reservoir capacity; the Juniper site on the Yampa River in Colorado, with 1,500,000 acre- feet; and the Dewey site on the Colorado in eastem Utah, with 2,370,000 acre-feet. From the standpoint of major lower river regulation, these sites left much to be desired. First, none of them offered sufficient storage capacity for adequate river regulation. Second, they were all too far from the pJaces where regulation was most needed - hundreds of miles separated them from the irrigable fields of Arizona and California. And third, there were too many tributaries below these sites capable of causing destructive floods. Two excellent sites were found in the lower basin - Boulder Canyon and Black Canyon. Each site offered potential reser- voir capacity of over 30,000,000 acre- feet. However, each site also posed un- precedented engineering problems. 13