OCR Text |
Show in the character of the soil. From the sink, east to the Colorado, the entire tract has been formed by the deposit of river silt. This deposit is not of local origin, but has been brought down in past ages by the Colorado, from its sources in the mountains of Colorado, Utah, Wyoming, New Mexico and Arizona, and through its water passage of thousands of miles has been worked into an homogeneous mass, hence there can be but little change in its character. Within this body there is neither sand, gravel nor rock: It can be described as a finely pulverized river silt, containing from 10 to 20 per cent, of clay, and in the percentage of clay is the only change in its structure. It is sufficiently porous to admit of easy irrigation and cultivation, and yet contain sufficient clay to make it very retentive of moisture, and these are the two structural necessities required to make irrigation a success. It is impossible to state the depth of the sedimentary formation, as it extends to what formerly was the bottom of the Gulf, but from my observations the depth of soil to the clay sub-soil varies between 20 and 250 feet. Water Supply. With the exception of the Columbia, the Colorado River is the only stream in arid America that is capable of supplying with water all of the lands that are subject to irrigation from it. According to the United States geological survey, it drains an area of 242,000 square miles. Two-thirds of this area is an elevation of over 5,000 feet, where the precipitation is heavy and in the form of snow, which melts during the spring and summer months, giving the |
Source |
Original book: [State of Arizona, complainant v. State of California, Palo Verde Irrigation District, Coachella Valley County Water District, Metropolitan Water District of Southern California, City of Los Angeles, California, City of San Diego, California, and County of San Diego, California, defendants, United States of America, State of Nevada, State of New Mexico, State of Utah, interveners] : California exhibits. |