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

page 167

PROBLEMS OF IMPERIAL VALLEY AND VICINITY. 167 Transportation, Denver & Rio Grande Railroad (standard-gage line, connecting with narrow gage at Durango). Farmington, nearest station, is at the northern edge of the project and 50 miles from the outer portions. ; . , Irrigation plan.-Diversion is anticipated on the San Juan River about 10 mnes below the mouth of Pine River. The main canal will traverse steep, rocky hillsides for 35 miles and then emerge in the Chaco Canyon drainage area, which is a vast basin of mesa land with prominent drainage channels and eroded slopes. This area contracts at the Carrizo Mountains, on the Arizona State line, which :forms the logical end of the project. The main canal to this point would be about 300 miles long. As an alternative the project might be developed only to include lands-east of Chaco Canyon, the irrigable area then being possibly 125,000 acres and length of main canal 135 miles. The main canal with either development would cross much very difficult country, and the first 35 miles would be especially difficult. No instrumental surveys have been made for canal lines, and the rough reconnaissance observations made by, Various -engineers agree on the costly construction and on not more than 50 per cent of lands covered being irrigable. , • .,- ! . ,, Duty pf water.-With long main canals and a long dry growing •season, a diversion of 3.5 acre-feet per acre is anticipated. Consumptive use of 2 acre-feet is estimated, making a return flow of ,1.5 acre-feetper acre. , > Water supply.-Discharge records are available as follows; Recorded stream flow. Year. Period. Discbarge. Station. 1908 1909 1910 1911 June 6 to Dec. 31.......'.. January to November___ January to December..... January 15 to September. Acre-feet. 1,080,000 1,150,000 11,170,000 1,810,000 Turley. ,Do. Bloomneld. 1 Partially estimated. From 1913 to 1917, inclusive, discharge was measured at Farming-ton. Deducting the Animas River discharge from Farmington record gives an average of 1,400,000, which is comparable to the Bloomfield station, both including erratic unknown run-off from Largo Canyon. The average annual run-off at the diversion site is estimated at 1,400,000 acre-feet, or jast equal to the demand for 400,000 acres after deducting for consumptive use, of additional areas on the headwaters to the extent of 26,000 acres at the rate of 1 acre-foot per acre on the Navajo and Piedra rivers and 50,000 acres at 1.25 acre-feet -per acre on the Pine River. No account need be taken of present or future acreage below the point of diversion, as return flow from this project willfully supply them. If 1914 be taken as an average year, storage requirementts for proj-*ects of 125,000 acres and 400,000 acres would be as follows':