摘要:

The American Geophysical Union was established in 1919 as the American Committee of the International Union of Geodesy and Geophysics, and its Executive Committee is the Committee on geophysics of the National Research Council. The objects of the Union are to promote the study of problems concerned with the figure and physics of the Earth, to initiate and coordinate researches which depend upon international and national cooperation, and to provide for their scientific discussion and publication. In the accomplishment of these objects, the Union is divided into Sections following the plan of organization of the International Union of Geodesy and Geophysics. There are now eight Sections, namely, (a) Geodesy, (b) Seismology, (c) Meteorology, (d) Terrestrial Magnetism and Electricity, (e) Oceanography, (f) Volcanology, (g) Hydrology, and (b) Tectonophysics. A Section of Geophysical Chemistry was discontinued May 31, 1924, as the International Union had failed to provide such a Section. The Section of Hydrology was established November 15, 1930—matters pertaining to scientific hydrology referred to the American Geophysical Union had been previously looked after by special committees on Hydrology. The Section of Tectonophysics was established April 9, 1940, for the purpose of promoting and encouraging research of fundamental importance to our knowledge of Earth‐structure not covered in any one of the other Sections of the Un

ISSN:0002-8606    

DOI:10.1029/TR022i003p00587

年代:1941

数据来源: WILEY

摘要:

In semiarid regions near the seacoast excessive pumping of wells is liable to cause salt‐water intrusion either from the ocean itself or from relatively impervious marine sedimentary rocks surrounding the aquifer which yields ground‐water. Since the ground‐waters of semiarid regions commonly have a relatively high and variable concentration of dissolved salts, a slight increase in concentration, such as is found by measuring resistivity [see 8 of “References” at and of paper[, may not alone be sufficient to prove the presence of sea water. On the other hand, since ground‐waters usually differ widely from sea water in composition, it might be thought that changes in the proportions of different chemical components of well‐waters in the direction if sea water could be used to detect the beginnings of admixture. Actually, however, the observed changes in composition of well‐waters may be quite different from those that would occur on simple mixing with a small portion of sea water owing to the modifications which sea water itself may undergo as it passes through the ground or through marine and estuarine sediments. The absence of those proportional changes which would result from a direct mixture of sea water and ground‐water cannot be taken as a warrant for disregarding other signs of salt

ISSN:0002-8606    

DOI:10.1029/TR022i003p00593

年代:1941

数据来源: WILEY

摘要:

The viscosity of a clay suspension is measured for varying degrees of concentration and flocculation and the results interpreted as a possible explanation of the behavior of underflows of water, with high clay concentration, through reservoirs.When we attempt to explain, why, and under what conditions non‐mixing underflows are possible, we must remember that an underflow is a problem of hydrodynamics, like any other flow. We must also remember that, from the standpoint of hydrodynamics, laminar flow Is the normal kind of flaw in a liquid and that laminar flow will take place everywhere unless it is disturbed. These disturbances are called turbulence and are created mainly along solid wails or in places with a discontinuity of velocity. Both kinds of sources for the creation of turbulence are found in the case of an underflow, the solid surface at the bottom, and the discontinuity at the interface between lake water and underflo

ISSN:0002-8606    

DOI:10.1029/TR022i003p00597

年代:1941

数据来源: WILEY

摘要:

The general theory of the vertical distribution of suspended sediment in a turbulent water stream has been sufficiently well established to permit its use in making calculations of the suspended material transportation in connection with engineering problems. It is the purpose of this paper to present simplified methods for making the necessary calculations of the total amount of sediment transported in suspension in a river or canal. Field‐data is presented for purposes of checking the validity of the various approximations made, and to indicate the accuracy of the proposed calculation

ISSN:0002-8606    

DOI:10.1029/TR022i003p00603

年代:1941

数据来源: WILEY

摘要:

The purpose of this paper is to present briefly the results of experiments on the transportation of a suspended load of sediment by water. In the experiments, measurements were made of the total load carried by such flows and of the distribution of the load in the flow. This work was done by the Cooperative Laboratory of the Soil Conservation Service and the California Institute of Technology, as a part of the research program of the laboratory having to do with the mechanics of entrainment, transportation, and deposition of sediments. The objective of these studies is to clarify the mechanism of erosion and to establish physical laws governing erosion‐phenomena that will be of assistance in the work, of the Soil Conservation Service. The present paper is submitted as a contribution to this objectiv

ISSN:0002-8606    

DOI:10.1029/TR022i003p00608

年代:1941

数据来源: WILEY

摘要:

River engineering has been faced for many years with the dilemma that, on the one hand, its accumulated experience is sometimes inadequate for reliable prediction of river behavior, while, on the other hand, there has been little attempt at systematic quantitative evaluations to “discover identity in difference”—all the above referring particularly to the form of river‐channels, in cross‐section, plan, and profile. The purpose of this paper is to review certain principles which afford a rational derivation of the profile of river‐beds and to test the results on several Amer

ISSN:0002-8606    

DOI:10.1029/TR022i003p00622

年代:1941

数据来源: WILEY

摘要:

This paper sets forth, certain fundamentals relating to the dynamics of meandering streams derived from extended observations made by the writer on streams ranging in size from mere rivulets to as large as the Lower Mississippi River. These observations were supplemented by others made on undistorted as well as on distorted experimental models. The nomenclature and definitions herein were selected by reference to what appeared to be the best usage found in the literature on the subject.

ISSN:0002-8606    

DOI:10.1029/TR022i003p00632

年代:1941

数据来源: WILEY

摘要:

Recent studies made in the Ohio River Division Office of the United States Engineer Department have involved the analysis of storage‐ and discharge‐relations and have resulted in development of approximate flood‐routing procedure for the Lower Ohio River Valley where the situation is complicated by the confluence of the Ohio River with the Mississippi, Tennessee, Cumberland, and Wabash rivers, in this paper are presented the results obtained from study of the following reaches:(1) Reach terminating at the confluence of the Ohio and Mississippi rivers at Cairo, Illinois and extending from Thebes, Illinois, on the Mississippi River, 44 miles above Cairo Point, and from Golconda, Illinois, on the Ohio River, 78 miles above Cairo Point.(2) Reach terminating at Shawneetown, Illinois, on the Ohio River and extending from Mt. Carmel, Illinois, on the Wabash River, 95 miles from Shawneetown, and from Evansville, Indiana, on the Ohio River, 66 miles from Shawneetown.(3) Reach of the Cumberland River from Dover, Tennessee, to its mouth, a distance of 88

ISSN:0002-8606    

DOI:10.1029/TR022i003p00637

年代:1941

数据来源: WILEY

摘要:

In the States of Indiana, Kentucky, Michigan, Ohio, and Tennessee, there are tame 440 reservoirs exclusive of farm ponds, built for water‐supply, power, flood‐control, recreation, or conservation. Their aggregate cost is estimated at $415,000,000.Approximately 25 of these reservoirs have been studied for the purpose of estimating their rates of silting. Most of the field‐examinations were of the nature of a reconnaissance, although data on several reservoirs obtained from published reports were apparently derived from instrumentally controlled surveys. Examinations by the Soil Conservation Service consist of soundings and determinations of depths of sediment at numerous points in the reservoir, but because instrumental control was not used the results, which are averages of the measurements, must be considered only as approximate and not comparable with Soil Conservation Service detailed surveys. They are, however, a useful and inexpensive method of making rough estimates of silting damage and determining the range of magnitude of sediment‐production per unit of area. They are probably at least as good as, if not better than, suspended‐load records of only one or two years'

ISSN:0002-8606    

DOI:10.1029/TR022i003p00649

年代:1941

数据来源: WILEY

摘要:

The first law of thermodynamics requires that a balance of energy exist between the loss and gain in heat at the surface of a body of water. Thus, the insolational energy absorbed at a water‐surface may be equated to the heat‐losses from the surface through the process of radiation, conduction, and convection and to the energy expended in raising the temperature of the water and in the process of evaporation.In 1915 Schmidt [see 11 of “References” at end of paper] applied this principle of conservation of energy to the problem of evaporation and computed the moisture‐losses from large bodies of water. Ångström [1], in 1920, published a paper on the application of this energy‐equilibrium to the problem of evaporation from lakes and adequately pointed out its limitations. Schmidt's treatment of various elements in the heat‐balance relations was shown to be unsatisfactory. Specifically, Schmidt's general assumptions regarding the ratio between the heat carried away by convection and heat used for evaporation which involved the further assumption that the water‐bodies under consideration will be generally warmer than the air we

ISSN:0002-8606    

DOI:10.1029/TR022i003p00655

年代:1941

数据来源: WILEY