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IV. NEGOTIATIONS CONCERNING THE POWER

CONTRACTS 29. Hydrology of Boulder Canyon Reservoir. 30. Value of Boulder Canyon power. 31. Notices to prospective applicants for power. 32. Summary of applications for power.

33. Tentative allocation. 33-A. Statement by Secretary Wilbur at close of power hearings,

November 13, 1929. 34. Agreement of March 20, 1930, among major California

applicants. 35. Agreement of April 7, 1930, among municipalities for alloca- .

tion of their share of power. 36. Letter from the Chairman of the Southern California Edison

Co.

471

[APPENDIX 29]

HYDROLOGY OF BOULDER

CANYON RESERVOIR

WITH REFERENCE ESPECIALLY TO THE HEIGHT OF THE DAM TO BE CONSTRUCTED

BY E. B. DEBLER

(OMITTING CHARTS AND APPENDIXES) 31

150912–33

473

HYDROLOGY OF THE BOULDER CANYON RESERVOIR WITH REFERENCE ESPECIALLY TO THE HEIGHT OF DAM TO BE ADOPTED

INTRODUCTION

The Boulder Canyon project act (45 Stat. 1057), approved December 21, 1928, was largely predicated on data developed prior to 1924. The board of engineers appointed in pursuance of S. J. Res. 164, approved May 29, 1928 (45 Stat. 1011), in its report of December 3, 1928, considered some data which became available subsequently but was unable in the limited time available to give detailed consideration to these matters.

The Boulder Canyon act prescribed a minimum reservoir capacity of 20,000,000 acre-feet. The plans covered by the report of the board of engineers contemplated a dam to raise the water level 550 feet, with an initial storage capacity of 26,000,000 acre-feet. Marked reductions in the cost of producing power in southern California resulting from improvements in the art of steam power production make it necessary to achieve the lowest obtainable cost of production to insure the financial success of the project. Unexpectedly large power demands make it desirable to produce the maximum power consistent with engineering feasibility and cost.

Studies made in connection with the 1924 report indicated a declining cost for power with increasing reservoir capacities up to fully 34,000,000 acre-feet.

The present report is based on all data available to date and is directed primarily to the consideration of high level dams with especial attention to schemes of reservoir operation intended to produce a maximum power output consistent with adequate flood protection and an assured irrigation supply.

A number of important features have been given consideration to a degree of detail not properly presentable in this summary. Descriptions thereof will be found appended in a series of exhibits.

BOULDER CANYON STREAM FLOW

Discharge records.

Yuma gage height records are available from 1878 to date but discharge measurements date only from 1902. Gaging stations were established on the main tributaries in the upper basin at various times in and after 1895. Desultory measurements were made at Bullshead, 1902-03; Hardyville, 1905-1907; and Topock, 1917-1922. Dependable records have been obtained at Lees Ferry beginning with 1922, and at Bright Angel and Topock beginning with 1923. Methods in use at Yuma in earlier years, while in keeping with methods in common use at the time, were not adequate to obtain accurate records in periods of high water. Most of these imperfections would tend to indicate discharges higher than actual; some would tend to produce the opposite result. The Colorado River board reported an opinion that Yuma discharges should be reduced 10 per cent.

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