Imperial County CA Archives History - Books .....Formation Of The Colorado Desert 1918 ************************************************ Copyright. All rights reserved. http://www.usgwarchives.net/copyright.htm http://www.usgwarchives.net/ca/cafiles.htm ************************************************ File contributed for use in USGenWeb Archives by: Joy Fisher sdgenweb@yahoo.com February 14, 2006, 6:18 am Book Title: History Of Imperial County California CHAPTER II FORMATION OF THE COLORADO DESERT LONG ago, before the memory of man, but comparatively recent from a geological standpoint, in what is known as the middle tertiary period, the waters of the Gulf of California reached up as far as the slopes of Mounts San Jacinto and San Bernardino, taking in all of the region now known as the Imperial Valley, Sal ton Basin and Coachella Valley, an area of over 3000 square miles; the whole of the present delta into which emptied the erratic and unreliable Colorado River—the real heroine of the romance of the desert—for without the Colorado the waters of the sea would still bathe the foot of the mountains. Although deprived of a part of its glory by a misnaming of the upper branches, the Colorado is one of the long rivers of the world, being about 2000 miles in length, including the Green River, which unites with the Grand to form the Colorado, the Green being really a continuation of the Colorado itself. The river drains a region of about 300,00x3 square miles, the southwestern part of Wyoming, west Colorado, east Utah, Nevada and new and old Mexico. Most of the land is extremely dry, with an average rainfall of only &y2 inches, the river being supplied chiefly from the melting snow of the mountainous parts of Wyoming, Utah and Colorado. The Colorado Valley is distinctly divided into two sections. The greater part of the lower third is but little above the level of the sea, some parts in fact being more than 200 feet below the sea level, but here and there occasional mountain ranges rise to a height of from 2000 to 6000 feet. Its northern boundary is an almost vertical wall of cliffs, often thousands of feet high. The tableland which forms the rest of the valley is from four to eight thousand feet above the sea, and is surrounded on all sides but the south by snow-capped mountains, some of which are 14,000 feet high. The whole upper part of the Colorado Basin is cut by innumerable gorges of inaccessible depths, caused by the river and its branches. They are dry, however, except during the rainy season and when the snow melts on the mountains. The erosion by the Colorado and its tributaries has played a leading part in making the geography of the country. All of the silt, broken and powdered rocks, vegetation and other rubbish eroded by a river is held in suspension while the river is moving rapidly; it is only when it spreads out, becoming shallow and sluggish, that its burden is deposited along the banks and on the bottom. The Colorado reached no such point until it emptied into the Gulf of California, known at various times as the "Sea of Cortez," the "Sea of California" and the "Vermillion Sea," the latter name originating from the red color imparted by the sediment-laden river, which has been called "The Nile of America." That the valley was originally an arm of the gulf is shown by the shell incrustations and reefs of oyster shells. That the level of the country was raised by volcanic uplifts as some contend seems to be disproved by the fact that the water lines are all unbroken and do not show any evidence of any convulsions of Nature. Hence the theory that the formation of the valley was caused by the silt of the Colorado spreading over the bottom of the gulf, thus displacing the water, seems the right one. Little by little the silt was deposited, and little by little the sea retreated, until what had been the sea became low marshy land, with the river meandering through banks of its own creating. But with the melting of the mountain snow the sluggish, sleepy river, basking lazily in the sun, became a veritable demon of savage irresponsibility, going wherever it would and leaving its burden. At such times it broke all bounds set by previous deposits. During one such flood such a vast amount of debris was deposited that an area in front of its mouth was covered by silt which rose higher than the normal height of the river, so that when the flood subsided a great dam was formed which shut off the northern portion of the gulf (now the Imperial, Salton and Coachella valleys). The channel connecting the two portions must have become more and more shallow until it filled up so that the tide no longer flowed in and out, thus forming a lake the southern boundaries of which were the silt and mud from the Colorado. Prof. Blake's theory, formed from his investigations when with the Williamson expedition, is that at first this lake was kept fresh by channels from the river, but these filling up shut off the supply, and being shut away from the sea also, a rapid process of evaporation took place under the hot rays of the sun and the dry winds, and in the course of a few years the lake dried up. Wharton James on the contrary contends that as the shut-off portion of the gulf contained salt water, that it evaporated by natural processes, and was filled with fresh water by the overflow from the Colorado breaking over channel and dam and forming the ancient Alamo River through which part of the Colorado flowed into the basin and created a fresh-water lake, which it continued to supply as the years passed, keeping as a lake for a time what had been first an arm of the gulf, then a dry basin hundreds of feet below the sea level, then a lake, then dry land again, but how often this region alternated between being lake and dry land no one knows. It is assumed the Indians occupied the basin while dry, which will explain their tradition that after they had lived there many years they were driven out by the floods. This may have happened many times before another flood epoch came and built a new dam across the Alamo channel, which closed the fresh water supply, and the Salton Sea again dried up until it was filled by accident in 1905 through a miscalculation of the Southern California Improvement Company's constructing engineer as to what might be expected of the Colorado River, giving the modern world the opportunity to see Nature at work. But while the cut made by the Southern California Improvement Company was responsible for the divergence of the river primarily, scientists believe from the behavior of the river since that it would have happened from natural causes shortly, anyway. But what was of no particular moment in prehistoric times became a calamity when the basin was occupied by railroads, farms, orchards and homes. Hence at the present time all the ingenuity of man is being brought to bear upon the problem of curbing the riotous Colorado and making it return to its former channel. The land formed by the deposit from the river was exceedingly rich, but unfortunately, except for flood waters, extremely dry, the annual rainfall, as before stated, averaged only about 8^ inches, and it presented all the aspects of a desert land. The Colorado Desert, which is the local name given by Prof. Blake in I853 to that portion of the great Sonorian Desert which lies between Parker, Arizona, and Picacho, California, a long, narrow strip of country containing not less than 500,000 acres of alluvial soil, needing only water to make it fertile. The temperature registers as low as 17 degrees, and occasionally in summer as high as 125 degrees. In the cool of the morning the air is very stimulating and invigorating, but the heat of the afternoon is intense and exhausting. The rainy season is from December to February, but sometimes there are showers in the heart of summer. Additional Comments: Extracted from: THE HISTORY OF IMPERIAL COUNTY CALIFORNIA EDITED BY F. C. FARR IN ONE VOLUME ILLUSTRATED Published by ELMS AND FRANKS BERKELEY, CALIFORNIA 1918 File at: http://files.usgwarchives.net/ca/imperial/history/1918/historyo/formatio230nms.txt This file has been created by a form at http://www.genrecords.net/cafiles/ File size: 8.2 Kb