THE IRRIGATION AGE. 



83 



to the Gulf of Lower California. The occupants of 

 the Imperial Valley now interested in irrigation, 

 have erected a levee along the north line of Volcano 

 Lake to prevent its water from entering the Imperial 

 basin through New river. 



It is evident, that as soon as the Colorado began 

 to flow into Volcano Lake, the decrease of velocity in 

 the Lake caused silt to settle rapidly, and this has con- 

 tinued from 1910 to the present time. This process, 

 if not interferred with, will eventually raise the level 

 of Volcano Lake, so that water cannot be confined in 

 it by means of levees. 



After this has occurred, the question as to where 

 the water will break out is one, on which opinions may 

 differ, but it may be conservatively stated, that it is 

 just as likely to break over into Imperial Valley as 

 in any other direction. 



When the Colorado began to flow through Bee 

 river in 1910, apprehension was justly felt by settlers 

 in Imperial Valley. The cause of this change of chan- 

 nel was the raising of the Colorado river bed, below 

 Bee river, through deposits of silt. This situation was 

 deemed very serious and too complex for the interests 

 of Imperial Valley to handle alone, and the government 

 of the United States interested itself to the extent of 

 approximately $1,000,000 appropriated for turning the 

 Colorado back into its own channel, by closing the 

 inlet of Bee river. This work was begun in the early 

 part of 1911, and continued throughout the greater 

 part of the year, without success. 



Much controversy has existed as to why the gov- 

 ernment and its engineers failed to successfully re- 

 divert the Colorado from Bee river into its own channel. 

 The various discussions of this have heretofore ig- 

 nored the main points involved. The attempt was 

 made to turn the water back by means of levees, and 

 this method was not open to criticism, but there are 

 two elements, which must have been overlooked. 



The first one of these was the fact that the channel 

 of the river below the break was heavily silted. The 

 writer, who was at that time consulting engineer for 

 the Mutual Water Companies in Imperial Valley, 

 controlled by the consumers of water, and not by the 

 receiver of the California Development Co., gave 

 careful consideration to and examined the channel 

 after the attempt to close the break had failed. 



Observations showed that the bed of the Colorado 

 river had been raised by silt, partly produced before 

 the break, by reason of the wide stream below that 

 point, partly during the period of changing into Bee 

 river, on account of the diminishing flow causing a 

 lower velocity in that part of the Colorado and partly 

 after the bed had become dry, causing vegetation to 

 spring up and the wind to carry sand and dust, which 

 lodged against the growth of vegetation. 



No measurements were taken to determine how 

 much to lower the Colorado river channel at this 

 point, before the levee across the upper end of Bee 

 river was begun. Neither was the levee located as 

 close to the inlet of Bee river, as would have been 

 possible, but was placed a considerable distance down 

 stream, which made it necessary to build higher, than 

 if it had been placed at the very outlet of the Colorado 

 river into Bee river. 



The failure to close the break does not demon- 

 strate rhat the attempt would not have been successful 

 had the matters here referred to been investigated, and 

 the work ordered accordingly. There is no doubt that 



the failure to close the break was due to the excessive 

 pressure, on account of the high level to which the 

 water had to be raised against the trestle and rock dam 

 across Bee river. Had the required height been only 

 a few feet less there is no doubt that the attempt would 

 have been a complete success. But there is a limit to 

 the pressure of silt which a pile trestle and rock dam 

 on Colorado river will stand, and the limit was but 

 slightly exceeded. 



If a large dredge had been operated in the main 

 channel of the Colorado river below the break both 

 before and during the installation of the pile and rock 

 dam in Bee river, the height to which the water must 

 be raised would have been diminished and the closure 

 would have been effected. 



Careful computations show that locating the dam 

 higher up Bee river, and doing the necessary dredging 

 at that time, would have decreased the height to which 

 the water would have to be raised, where the pile 

 trestle and rock dam was placed, by not less than four 

 feet, and possibly as much as five feet. There is no 

 doubt that the difference would have been sufficient 

 to keep the pressure on the rock fill within safe limits, 

 so that it would have been successful and permanent. 



Since 1911 no further attempt has been made to 

 restore the Colorado to its own channel and the whole 

 stream has ever since been flowing through the Bee 

 river into Volcano Lake. The increase of elevation 

 in Volcano Lake, from the silt settling within it, has 

 already caused trouble, and in the spring of 1914 the 

 Volcano Lake levee broke, sending a large volume 

 of water into Imperial Valley. This overflow only 

 affected a section of country in Mexico, as it entered 

 the channel of New river before reaching the United 

 States. 



Nevertheless, it caused considerable apprehension 

 on account of the volume of water in New River, 

 which threatened to undermine the irrigation flumes 

 and bridges across that stream. Immediate alarm was 

 caused by this break and all interested began to assist 

 in the repair of the Volcano Lake levee to prevent the 

 water from flowing north into Imperial Valley. This 

 work was successfully done, and the river is at present 

 kept under control in Volcano Lake, and flows 

 through Hardy's Colorado into the Gulf of Lower 

 California. 



The real problem being confronted, however, is 

 to give recognition to the fact that, unless something 

 of a permanent nature is undertaken, the area covered 

 by Volcano Lake will soon be raised so high that no 

 level will confine the water along the north and keep 

 it from entering Imperial Valley. While there is no 

 cause for immediate alarm, as it is still possible to 

 raise the levees higher by properly extending them, yet 

 it is better to take the matter up and provide a plan 

 to avoid any further catastrophe, than to wait until 

 something occurs to equal the overflow which occurred 

 from 1905 to 1907. 



Just what the details of such plans are to be it 

 is impossible to announce without a further study of 

 the situation, but enough is known to assert that it 

 will have to be both dredging and building of dikes. 



It is not even certain that at this time it will be 



best to have the river returned to its original channel 



below the inlet of Bee river. It has flowed for nearly 



five years through Bee river into Volcano Lake, during 



(Continued on page 91) 



