OCR Text |
Show 290 REPORT OF THE CHIEF OF ENGINEERS. DIVERSION OF THE COLORADO R1VEK. By Department letter of May C, 1875, in addition to the regularly organized work of the season, a special preliminary examination as to tlie feasibility of diverting the waters of the Colorado River of the West for purposes of irrigation was authorized, and, as stated in my last annual report, Lieutenant Berglaud was intrusted with the charge of a separate party for this purpose. . Both a summer and a winter trip were made. In submitting his report, Lieutenant Bergland, after describing the organization of the party, the routes followed, and discussing the question of the diversion of the river, decides, as the result of his first trip, that it cannot be successfully done at any point between the foot of the lower Grand Canon and the head of the Colorado Valley, an approximate distance of 320 miles, because of the outlying ridges with high passes, through some of which the river has cut its way ; and as a result from his second trip, he concludes that no such diversion can be successfully made at any point along the present channel of the river within the territory of the United States. As shown in ury~ report to the Chief of Engineers of April 27, 1875, in pursuance of a communication of Mr. E. F. Beale to the President, under date of March 20,1875, no diversion of the river on a large scale could practically be made between the junction of the Green and Grand rivers and the poiut of its emergence from the Grand Canon, uear which Lieutenant Bergland began his survey. He has examined the general course of the river for a distance of 32G miles, and caused sections to be made near the mouth of the Virgin and Camp Mohave. Observations were made at Liverpool Lauding and about Fort Yuina, with profiles from Fort Ynma westward to the depressed area near Indian Wells, and from Algodones to the westward, in vicinity of the bed of New River, so called. The volume of water measured at Stone's Ferry, near the mouth of the Virgin, was found to be, in August, 1875, approximately 18,410 cubic feet per second, or sufficient in a mount to irrigate 3,082,000 acres, assuming one cubic foot per second for each 200 acres. At Camp Mohave in September the flowage was 8,i>80 cubic feet per second, or sufficient at the assumed rate for the irrigation of an area of 1,730,000 acres. At Fort Yuma in March, 1870, the volume of water was found to be 7,058 cubic feet per second, sufficient for the irrigation of 1,531,000 acres. The estimate of the volume of water necessary for the irrigation of a single acre for one crop, (one two-hundredth part of a cubic loot per second, used 200 days,) is taken from the reportof the commissioners, Messrs. Alexander, Mendell, and Davidson, upon the irrigation of the Sau Joaquin and Tulare Valleys of California. By assuming the increased area of the cross-sections of the river at high water as shown by the section made at Stone's Ferry, the velocity of discharge remaining the same as that noted as the mean velocity at that point in August, the increase of the volume of discharge would be 31,439 cubic feet per second, making the total volume of discharge nearly 49,849 cubic feet per second, or a little less than three times the volume observed in the middle part of the heated season. Could this amount be utilized upon ordinarily compact soil, which, however, is partially impracticable, approximately 10,100,-<M)0 acres of laud could, by its instrumentality, be brought under cultivation. The increase of discharge upon the assumption of a mean velocity ;tt high water, the same as that observed in September at Camp Mohave, would give 34,274 cubic feet at that point; because of the large area of bottom-lands overflowed at high stages, the velocity would be increased but slightly. |