Page 118

Metadata

Title
Page 118
Source
Colorado River problem
Is Part Of
http://digital.library.unlv.edu/u?/dig,8
Full text
DEBLER ON THE COLORADO RIVER PROBLEM 423 excess of any since 1902, with a maximum discharge for that year at Needles, estimated by Santa Fe railroad engineers on the ground, at 384,000 sec-ft. The maximum discharge at Laguna Dam since 1902 has been 186,000 sec-ft. Herman Stabler, M. Am. Soc. C. E., estimated the annual discharge for 1884 at 27,200,000 acre-ft. as compared with a discharge of 21,100,000 acre-ft. for 1920 on which Colonel Kelly's recommendation of 4,000,000 acre-ft. of storage is based. The difference of 6,100,000 acre-ft. between the discharges of these two years is largely water that would have to be stored if discharges at Yuma are to be maintained at 75,000 sec-ft. as recommended by Colonel Kelly. The required storage capacity to hold the 1884 flood to 75,000 sec-ft. would then be 10,000,000 acre-ft. compared with 4,000,000 acre-ft. recommended by Colonel Kelly and 8,000,000 acre-ft. proposed by the U. S. Bureau of Reclamation. The problem of flood control is not one of water alone; it contains an element of possibly even greater importance—silt control. It may be granted that power dams, if constructed on the Colorado River in the immediate future, will cause Colorado River waters to leave the canyon region practically desilted. The present topography of the stream bed and valleys below Boulder Canyon is a balance between the silt supply brought by the stream from upper sources and existing channel conditions. When the silt supply is cut off, this balance is disturbed, and the result is entirely beyond the ability of man to forecast with certainty. Will it be safe to turn a continuous stream of 75,000 sec-ft. of comparatively silt-free water into a channel that has adapted itself to heavily silted water? To provide for expected, but wholly uncertain, developments from this change in character of stream flow, liberal allowance must be made for controlling the stream flow to discharges materially less than those proposed by Colonel Kelly. The paper outlines a permissible development at Mohave Valley in case Congress should deem some provision for flood control and irrigation necessary, and places the cost of the power plant at $35 per h.p., wholly omitting the cost of transmission lines. Estimates for Boulder Canyon indicate a cost of $76 per h.p. for the power plant and pressure tunnels with a plant capacity of 200,000 h.p. With the lower head available at Mohave Valley, the cost at that point would be no less. Adding to this amount the estimated cost of $115 per h.p. for the dam gives a total cost of $191 per h.p. for a power plant nearly 300 miles from the Southern California market as compared with a similar cost for competitive California sites not only nearer the market, but located so that advantage may be taken of transmission lines already constructed and not fully loaded. To produce this power the normal flow of the Colorado River must be increased very materially. If, for this discussion, it is admitted that the increase in normal flow caused by the construction of Boulder Canyon Reservoir would be a menace to the fullest possible use of Colorado River waters by reason of an immediate impetus in Mexican irrigation, the Mohave Valley plan for all practical purposes is open to the same objection. The inability of power revenues at the Mohave Valley site to repay the construction cost is probably best indicated by the fact that this dam site is

Cite this Item

When linking to this object, please use the following URL:

http://digital.library.unlv.edu/u?/lv_water,1725

Tags

Comments

Subscribe to recent comments

There are no comments yet. Be the first to comment below!

Comment on this object