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Show 10 THE ALL-AiCERICAN <3AI*£L. country in California and now known as the Imperial Valley. This delta cone was built across the ancient Gulf of California and cut off the Salton Basin from a connection with the gulf. Its crest follows a line slightly convex to the south from a few miles below Pilot Knob to the base of the detrital slope of the Cocopah Mountains west or northwest of Volcano Lake. Volcano Lake, now practically obliterated by deposits of silt, was a fiat depression on top of the broad deltaic ridge, from which there were outlets carrying water at the river's periodic high stages both toward the south into the gulf region and toward the north into the New Hirer country. Under the conditions as modified by human agency, the river has, as noted above, broken from its bed in recent years, first in 1905 (and 1907), near the apex of the delta, and again in 1909, 20 miles farther south. The river was turned back into its proper channel after breaking from its course near the head of the delta. The change made in 1909 put the river on the course toward Volcano Lake, as it flows to-day. Fortunately the point at which this change occurred at the head of the Abejas or Bee River, is so far downstream that by means of levees the river could be and has been prevented from taking a course down the north slope of the delta cone into Imperial Valley. The river must be kept on a course to the south, with outfall into the Gulf of California, if disaster to the Imperial and Coachella Valleys is to be avoided The river on its original course was as far east at certain points below Arizona as it could go. Its course brought it hard up against the first, second, and third mesas in Sonora. The only change of alignment, in a large sense, above the lowest of these points which the river could make was through a breach of its right or west bank below the California boundary and, therefore, upon Mexican territorr The elevation above mean sea Jevei of the apex of the delta cone of Colorado River near Yuma is about 125 feet. At the south boundary line of Arizona, being near the point where the river abandoned its original bed in 1909, the genera) elevation of the river bank land is about 88 feet. Thence westerly the ground falls toward Volcano Lake about 50 feet in a distance of 3 0 miles. From Volcano Lake there is a gradual fall toward the north into Imperial Valley and toward the south into the gulf region. The lowest point of the valley floor along the south boundary line of California, not considering the deeply eroded barranca of New River, is about 6 miles west of Calexico, about 11 feet below sea level. El Centro is about 50 feet and Brawley about 110 feet below sea level. In its natural condition, before being affected by human activities, the Colorado River below Yuma at its flood stages sent water over-bank to the right and left. Some of the right-bank flood water flowing down the slopes of the delta cone collected in channels which |
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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. |