摘要:

The work of streams is highly important in several fields of geology. Streams remove rock‐debris from the sites of weathering and transport it to flood‐plains, lakes, and ocean, where it is deposited to form new rocks. And during this erosion, transportation, and deposition, streams carve out and build up land‐forms, such as mountains, valleys, and plains. Because of these multifold results of stream‐activity, geologists have long been interested in the processes of stream‐work. Fifty‐six years ago, Gilbert formulated the major principles of stream‐work and land‐sculpture in a paper (G. K. Gilbert, Report on the geology of the Henry Mountains, U.S. Geog. and Geol. Sur. of the Rocky Mountain Region, pp. 99–150, 1877) which still, from the geological viewpoint, stands as the classic of the subject. The essence of Gilbert s ideas is the concept of graded streams—the concept that, either by cutting down their beds or by building them up with sediment, streams tend always to make for themselves channels and slopes that, over a period of years, will transport exactly the load of sediment delivered i

ISSN:0002-8606    

DOI:10.1029/TR014i001p00497

年代:1933

数据来源: WILEY

摘要:

1—The object of this paper is to stimulate interest in research relating to the division of the bed‐load at stream‐forks. This much‐neglected chapter in dynamics of streams has lately become of intense practical interest to hydraulic engineers as well as to scientists. Comparatively few of its many phases have been investigated to any extent.2—One well‐known phase, which has received much attention, is concerned with preventing sediment, more especially the heavier bed‐load materials, from entering the intakes of irrigation‐canals. This problem has intrigued man's ingenuity as far back as history is written, yet, today, its solution is far from perfect and some of its aspects are but li

ISSN:0002-8606    

DOI:10.1029/TR014i001p00506

年代:1933

数据来源: WILEY

摘要:

Hydraulic models for the solution of problems relating to the improvement of river and harbors may be grouped into two general classes distinguished from each other by the character of the bed employed. The purpose of this discussion is to present a brief but comprehensive outline of the methods of design and utilization of movable bed‐models, but before this can be done it will be necessary to differentiate briefly between the two types, and to describe their particular fields of usefulness.A fixed bed‐model may be considered as any hydraulic model simulating in miniature a natural or artificial watercourse whose bed and banks are essentially non‐erodible, so far as the problem at hand is concerned. Such models are particularly adapted to the precise determination of writer‐surface elevations, slopes, backwater, and sundry related factors and

ISSN:0002-8606    

DOI:10.1029/TR014i001p00509

年代:1933

数据来源: WILEY

摘要:

Battering seas, high tides, and storm‐driven, on‐shore winds always cause heavy damage along the seacoast and particularly at many beach communities. The destruction of property is heavy, houses are isolated by the high water, and the need of adequate beach‐protection is again vividly brought to the attention of the public.Along the New Jersey shore where the sandy beaches are used as playgrounds by so many people, it is usually the policy to extend the beach ocaanward by constructing jetties to hold the sand. This affords protection to the beach properties, since the wave‐energy is dissipated on the sand before any serious damage

ISSN:0002-8606    

DOI:10.1029/TR014i001p00512

年代:1933

数据来源: WILEY

摘要:

There are numerous types of waves with which the hydraulic engineer must deal, such as tidal waves, flood‐waves, waves in a canal due to the filling or emptying of a lock, power‐waves, and so on. Power‐ or increment‐waves will be the chief subject of this paper, and some mention will be made of experimental work on power‐waves and tidal waves which has been done at the Massachusetts Institute of T

ISSN:0002-8606    

DOI:10.1029/TR014i001p00516

年代:1933

数据来源: WILEY

摘要:

The Bureau of Agricultural Engineering has, since 1910, been studying the problem of runoff from small areas of land. Early studies would be considered crude today but the technique has been gradually improved until now we feel that the studies cover fairly adequately the purposes for which they are made.The first studies undertaken were made for the purpose of determining the amount of runoff that should be provided for drainage‐ditches that were to provide artificial drainage for cultivated land. When I joined the staff of Drainage Investigations, Office of Experiment Stations, in 1907, one of the moot points in the design of drainage‐ditches was the amount of runoff it was necessary to provide for in order to secure adequate drainage ditches was the amount of runoff it was necessary to provide for in order to secure adequate drainage. About the only data available were the records of the United States Geological Survey in regard to the discharge of streams and every engineer engaged in this work—and there were not so many of us in those days—had his opinion as to the proper amount of runoff to provide for, but very little information with which to back his judgment. Consequently, the arguments were numerous and at times

ISSN:0002-8606    

DOI:10.1029/TR014i001p00518

年代:1933

数据来源: WILEY