AZ vs. CA:24 California Exhibits, Vol. XXIV; Miscellaneous

page 77

PROBLEMS OF IMPERIAL. VALLEY AITD VICINITY. 77 IMPERIAL VALLEY INVESTIGATIONS-PRELIMINARY ESTIMATE. Surveys, reports, and estimates.-Surveys for the Imperial Valley extensions were made under the field direction of Engineer XH. J. Gault during the period of August to December, 1920, covering a gross area of approximately 600,000 acres,' exclusive of the Imperial irrigation district and the Salton Sea. The total line run was 292 miles of transit and 400 miles of levels, at a field cost of about $21 per mile for the total. The survey was very preliminary in character, consisting of an angle transit line followed by levels taken usually at 100-foot stations. The profiles generally did not follow very closely the selected grade lines, so they are not of much value for estimating yardage. No topography was taken, though at each-transit point the approximate slope of the ground was recorded. From these data and from inspection of the ground, appropriate percentages were selected to be added to the economic cut for estimating the yardages of excavation. The locations and profiles of the several canal lines surveyed are shown on the attached^ drawings. Two preliminary reports and estimates of the proposed extension project were prepared by Mr. Gault under dates of November 9 and November 16, 1920. The surveys were not completed till later (about Dec. 1) and Mr. Gault was then assigned to other work before completing his report. A soil reconnaissance was also made during the same period and covering the same area, under the field direction of Mr. A. T. Strahorn, United States Department of Agriculture, assisted by Mr. S. W. Cosby, of the University of California, and a preliminary soil report was prepared under date of November 12,1920. A more complete soil report covering this area has since been compiled by Mr. Strahorn, a summary oi which appears on pages 95 to 9,8 of this violume. Under date of November 27, 1920, Mr. A. P. Davis, Director, United States Reclamation Service, transmitted to the Secretary of the Interior a report on "Problems of Imperial Valley and vicinity,^ in which is briefly outlined, the plan of the proposed Imperial Valley extension system, including a summary of Mr. Gault's preliminary estimate. Detail surveys were made in 1918-19 under the field direction of Engineer Porter J. Preston, of an All-American canal extending from Laguna Dam to the west main canal of the Imperial irrigation district, for the irrigation of the Imperial irrigation district lands and also the proposed Imperial Valley extensions. A report and estimate was prepared by Mr. Preston under date of June 17, 1919; which report has been published as Part Two of the Ail-American Canal Board report of July 22, 1919, by Messrs. Mead, Schlecht, and Grunsky. Irrigation plan.-The plan of the Imperial Valley project is briefly as follows: To raise the crest of the Laguna Dam 2 feet an,d to enlarge the sluiceway and reconstruct the headworks and to enlarge the Ymna project main canal to the siphon drop sufficient to carry the Imperial Valley water. To construct a canal from this point on a grade contour to the Mexican boundary at Pilot Knob, and thence west on, the American side to the west main canal of the Imperial irrigation district. Outlets will be provided at points where this (the All-