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Show SOIL SURVEYS. CLASSIFICATION OF SOILS BORDERING THE IMPERIAL VALLEY. By Charles F. Shaw, Professor of Soil Technology, University of California. April 22,1921. The following^ report on the character of the soils of the regions bordering the ^Imperial Valley is based largely on the very careful and thorough examination of these soils that? w^as made by Mr. A. T\ Strahorn, of the Bureau of Soils, and Mr. S. W. Cosby, of the University of California;. The writer went over the area with these men, discussing the classifications that they had made and examined and studied the definite bodies of soils as delineated on their maps. Earlier investigations of portions of this area had been made in the course of other surveys in the Imperial Valley and some supjile-mental examinations were made of lands within the general region, but outside of the area included in this survey. All of this informal tion is drawn upon in the preparation of this report. • The soils of the east mesa are prevailingly sandy., ranging from a light sandy loam to a gravelly sand, with by far the larger part of & light fine sandy loam texture. The subsoils are likewise sandy, and quite uniform in character. These sandy soils rest upon a substratum of compact, stratified clays, at depths of 25 feet, more or less, below the surface. In a few places these compact clays are within- 6 feet of the surface and a few outcrops of this material,give some small areas of clay soils, usually containing alkali. These soils, together with a few areas of steep or rough land along the mesa margin, with the areas of wind-eroded "blow-outs" and the areas of dune sand, constitute the nonagricultural lands of the east mesa. A study of the soil maps shows that, excluding the dunes which border the mesa on the east, there are about 54,000 acres of nonagricultural land within the area of the east mesa. The survey shows that this mesa includes 169,739 acres of agricultural land, of which 125,227 acres are relatively smooth and level and of good quality, while 44,512 acres are more irregular, with scattered low mounds, ridges, or dunes that would need considerable work in leveling in order to prepare them for irrigation. While of a sandy texture, the agricultural lands of the east mesa are of good quality and should give good results with the crops suited to that region. North of the east mesa, from Niland to the Coachella Valley the soils are of a poor quality. Here compact stratified clays, carrying large quantities of alkali, are exposed on the surface or are covered by a veneer of recent wash from the mountains on the east. Some extensive deposits of this recent alluvium occur, but for the most part they are considered nonagricultural because of the ever-present danger of brief but locally severe floods which cause such serious erosion that in spite of < extensive control measures the railway roadbed is not infrequently washed out. Of the 107,435 acres in this 93 |
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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] : |