摘要:

This meeting of the South Pacific Coast Area for the Section of Hydrology of the American Geophysical Union is the eighth regional meeting to be held in Southern California and the second one in Pasadena, the first being held in 1936. While the South Pacific Coast Area includes more than California members, perhaps the reason for holding the meetings in California is because of the very high percentage of the membership in this State. The aim, however, has been to make the meetings regional in character. The attendance of members outside of California is evidence that the meetings have accomplished this purpose. Holding meetings in the northern part of the State one year and in the southern part the next has been the policy of the South Pacific Regional Committee.

ISSN:0002-8606    

DOI:10.1029/TR023i001p00059

年代:1942

数据来源: WILEY

摘要:

There now exists in theoretical analyses, in laboratory findings, and in conventional engineering‐design practice, a skeleton of facts on which a rational scour‐control procedure can be based. The writer has assembled these facts and stated them in as straightforward a manner as he believes, in consistent with current knowledge. Examples of the manner in which the analysis is taken into account in ordinary engineering design are given in support, ther

ISSN:0002-8606    

DOI:10.1029/TR023i001p00060-2

年代:1942

数据来源: WILEY

摘要:

Density‐currents are of major importance as transporting and sorting agents for fine sediment. Under unusual or extreme conditions they have a part in the distribution of surprisingly coarse material. The magnitude of the work they perform in sedimentation may have been obscured somewhat in recent years because there has been a tendency to think of density‐currents almost solely as turbid underflows in bodies of still water, especially in reservoirs that are fed by muddy rivers. Density‐currents are not limited to underflows, be they turbid or otherwise. Their occurrence is confined neither to reservoirs in particular nor to bodies of water in general. For example, dust storms usually are true density‐currents [see 1 of “References” at end of paper]. The importance of the atmosphere as a transporting and sorting agent is well known, and has been demonstrated clearly by evidence gathered by JOHAN AUGUST UDDEN [2], EDWARD ELWAY FREE [3], and many others. The fact that needs wider recognition is that the atmospheric transportation of sediment is accomplished very largely by densi

ISSN:0002-8606    

DOI:10.1029/TR023i001p00067

年代:1942

数据来源: WILEY

摘要:

It has been known for a great many years that the flow of water on steep slopes differs in many respects from that on milder slopes. Of the peculiarities the more important are: (1) A different law of resistance; (2) entrainment of air; and (3) roller‐waves.Regarding the first of these I have little to report except that my observations confirm completely the formula obtained by R. EHRENBERGER [see 1 of “References” at end of paper] for the mean velocity of flow in a rectangular channel of planed wood. In foot‐second units his formula reads:where V is average velocity, R is hydraulic radius, and S is the sine of the slope‐angle. This formula was based on tests on slopes from 0.153 to 0.707 and depths of flow up to one foot in a channel approximately ten inches wide. My own observations on a channel of similar size indicate that this formula is valid for much flatter slopes than 0.153 but I am not prepared to say what the lower limit of applicability is. At any rate the older CHECZY formula seems to agree closer with measurements than does that of ROBERT MANNING for slopes appreciably steeper than the

ISSN:0002-8606    

DOI:10.1029/TR023i001p00074

年代:1942

数据来源: WILEY

摘要:

As evaporation and transpiration are important elements in the water‐cycle, they must be given careful consideration before the available water‐resources of a drainage‐basin can be satisfactorily ascertained. Evapo‐transpiration or consumptive use of water involves problems of water‐supply, both surface and underground. This subject is increasingly significant, particularly in the irrigated regions of the West, where consumptive use may be several times as great as precipitation. The consumptive‐use requirement for water has become an important factor in the arbitration of controversies over major stream‐systems where the public welfare of valleys, states and even nations is involved [see 1 of “References”

ISSN:0002-8606    

DOI:10.1029/TR023i001p00076

年代:1942

数据来源: WILEY

摘要:

Two‐dimensional waves on a free‐water surface have been investigated experimentally in relatively narrow laboratory channels. In planning such experiments, there arises a question as to the width necessary to avoid appreciable losses of wave‐energy by wall‐friction. If the crest‐lengths were infinite, as assumed in the theoretical analysis of gravity‐waves [H. LAMB, Hydrodynamics, 6th Ed., p. 619], only internal and bottom friction decrease the wave‐energy and these effects are usually small but in laboratory wave‐tanks friction resulting from the very steep velocity‐gradients near the walls of the tank may have an effect so great as to render the experimental results worthless. The practical problem involved is the selection of a width of tank showing inappreciable wall‐effect rather than prediction of the loss of energy in a tank of

ISSN:0002-8606    

DOI:10.1029/TR023i001p00084

年代:1942

数据来源: WILEY

摘要:

Use of ground‐water has tended to increase progressively in recent years and probably will continue to increase in the immediate future; thus, it is to be expected that ground‐water supplies will become depleted or seriously overdrawn in some areas. With overdraft, the water‐level or pressure‐head of the fresh water falls so that salt water may be drawn into pervious beds along the ocean shore or near some other source of saline water. Bodies of ground‐water have been so contaminated in some areas along the Atlantic, Gulf, and Pacific coasts of the United States and locally within the interior; some of these areas of salt‐water contamination will tend to enlarge and others probably will develop. Problems encountered in the investigation of ground‐water supplies so contaminated create a challenge to develop improved and more precise methods for quantitative evaluation of salt‐wat

ISSN:0002-8606    

DOI:10.1029/TR023i001p00087-2

年代:1942

数据来源: WILEY

摘要:

Deliveries of Colorado River water to member cities of The Metropolitan Water District of Southern California began here at Pasadena on June 17, 1941, after an eight‐year aqueduct‐construction period that had been preceded by an equally long program of surveys, investigations, and planning. To many of us who have worked on the project, this date naturally seemed an end and a climax, rather than the real beginning of an even more important, if less exciting, period of operations, for which all earlier work had merely been a preparation. So before passing to present problems of technical interest, as indicated by the assigned title, the aqueduct had best be located and its construction completed for you briefly. It has been so often and thoroughly described in detail in many technical journals, however, that little repetition of general data is now justif

ISSN:0002-8606    

DOI:10.1029/TR023i001p00095

年代:1942

数据来源: WILEY

摘要:

Conditions of runoff and rainfall over the South Coast Area of California during the season of 1940–41 were such that the public at large was kept in a state of resigned expectancy. With the memory of the flood of March 1938 still fresh in their minds, people, through the months of February and March, 1941, began noting with growing apprehension the mounting precipitation‐figures and the constant and prolonged storms that covered the South Coast Area. Newspapers headlined rainfall as records approached 25‐year highs, 40‐year highs, and edged toward the all‐time recorded high. The layman in this territory, perhaps to a greater extent than elsewhere, instinctively realizes that a continual recurrence of rain is usually an indicator

ISSN:0002-8606    

DOI:10.1029/TR023i001p00103

年代:1942

数据来源: WILEY

摘要:

In the bulletins of the California State Division of Water Resources dealing with the various phenomena occurring within the area, South Coastal Basin is defined as the drainage‐areas of the Los Angeles, San Gabriel, and Santa Ana rivers, together with areas draining directly to the ocean between Topanga Canyon and San Joaquin Hills, as delimited on the key map of Figure 1.The area includes the south slope of San Gabriel and San Bernardino Mountains, an intermediate range of lower mountains and hills roughly paralleling them extending between the Santa Monica and Santa Ana Mountains, and valley‐lands lying between the two ranges and between the lower range and the ocean. The mountains and hills are shown cross‐hatched on the map and the valley‐lands left unshaded. Within these alluvial valleys lie the several ground‐water basins bounded and named on the map, which are here discussed. While the basin‐boundaries shown enclose also the tributary nonwater‐bearing mountain and hill areas, the ground‐water basins themselves are here considered to include only the alluvial water

ISSN:0002-8606    

DOI:10.1029/TR023i001p00108

年代:1942

数据来源: WILEY