摘要:

Quite aside from the distinction of this program as attested by the scientific character of the papers and the eminence of the speakers who are to follow me, it seems clear that your Reporter is determined to make this occasion unique in yet another way. I refer to his originality in proposing that a Symposium on Floods should be inaugurated by a paper dealing with the general subject of stream‐management. From time to time there have appeared in the engineering literature of this country, and I dare say in that of other countries also, reports of symposia on various aspects of water‐control and use, such as floods, droughts, pollution, power, navigation, etc. That these important subjects are inextricably related hydrologically, economically, and socially must be apparent, but in technical discussions such considerations have heretofore been conspicuous by their absence or by the cursory attention accorded them. Man does not live to himself alone, neither does the hydrologic cycle revolve only'around flood‐phenomena. It is gratifying to realize that in your deliberations upon various scientific aspects of floods and flood‐control, you propose to retain a broad perspective with relation to other factors affecting the use and regulation o

ISSN:0002-8606    

DOI:10.1029/TR020i002p00143-2

年代:1939

数据来源: WILEY

摘要:

Flood‐datais the designation herein applied to information concerning floods, statistical as well as analytical, needed by engineers and public officials in the formulation of plans for protection against high water and in the construction of structures such as dams, bridges, and storm‐drainage channels. The statistical phase is concerned with the cataloging and publishing of factual data derived from observations on rainfall, runoff‐rates, flood‐stages, and discharges. The analytical phase is aimed at determining from the observed data the frequency of occurrence and geographical distribution of flood runof

ISSN:0002-8606    

DOI:10.1029/TR020i002p00155

年代:1939

数据来源: WILEY

摘要:

From fragmentary historical notes and native legends, we are accorded a somewhat hazy view of flood‐phenomena under primitive conditions and are led to the conclusion that those phenomena occasionally assumed proportions approaching more or less closely to those observed during the later record period. Reasoning from cause to effect and consideration of specific examples in many localities, support the opinion that frequencies as well as magnitudes have increased, resulting either directly or indirectly from man's occupation and disturbance of the drainage‐areas, the vegetal cover, the flood‐plains, and facilities for surface‐de

ISSN:0002-8606    

DOI:10.1029/TR020i002p00157

年代:1939

数据来源: WILEY

摘要:

The magnitude of flood‐runoff and the degree to which it concentrates in river‐channels with respect to time is known to vary within wide limits. To a considerable extent these variations relate to the physiographic and edaphlc features of the drainage‐basins as they have been developed by the geologic and climatic history of the particular province in which they are located. Although storms of high intensity occur throughout the United States, the runoff therefrom has been observed to have certain inherent characteristics in wet or humid areas that are different from those in arid or semiarld regions even though the laws governing the flow of water either over ground or in river‐channels are universal in application. Essential features of flood‐behavior in wet or humid areas where stream‐flow is sustained throughout the year and river‐channels and valleys are comparatively well defined and permanent, differ from those in arid or semiarld regions where stream‐flow is very erratic and flashy and the channels are formed largely by occasional intense runoff rather than the slow and orderly development by the continuous occupancy by flowing water. Moreover the flood‐problem in areas where a part of the precipitation occurs as snow differs from that in areas where all the precipitation occurs as rain. Furthermore, in areas where snow does occur there seems to be a wide range in flood‐runoff characteristics depending upon the temperature in and altitude of the particular zone. Some of the different flood‐characteristics as they relate to total runoff and the concentration thereof are described herein and possible reasons therefor are related to conditions which seem to be more or less inherent in particular physiographic a

ISSN:0002-8606    

DOI:10.1029/TR020i002p00166

年代:1939

数据来源: WILEY

摘要:

For nearly a century, engineers relied upon empirical formulas to express the rainfall‐runoff relation. Good judgment and experience was required to approximate the effects of the complex variables intervening between rainfall and runoff. To the credit of many of these engineers, the history of their works has confirmed their judgment. It has not confirmed their formulas.We have gradually bettered our ability to estimate the magnitude and frequency of floods. This has been due to the acquisition of stream‐gaging records and to the rainfall‐studies of Meyer, Yarnell, the Miami Conservancy District, and others. Improved statistical methods have helped. The development of the rational method improved the art of estimating runoff—especially for small sewere

ISSN:0002-8606    

DOI:10.1029/TR020i002p00174

年代:1939

数据来源: WILEY

摘要:

The Geological Survey has been engaged for more than 50 years in measuring and publishing the discharge of streams of the United States. Measured discharges have ranged in quantity from a small fraction of a second‐foot measured volumetrically to more than 2,000,000 second‐feet measured by use of the current‐meter equipment recently developed by the Survey and described by the writer in the April 1938 issue ofCivil Engineering. In this work, systematic and generally complete records of discharge are being obtained at about 3700 gaging‐stations maintained and operated by the United States Geological Survey. A typical structure at which records of river‐stages are obtained is shown in Figure 1. A discharge‐record at a gaging‐station is usually derived from a record of stage by means of a curve or table showing the stage‐discharge relation as determined by measurements of discharge distributed over the

ISSN:0002-8606    

DOI:10.1029/TR020i002p00177

年代:1939

数据来源: WILEY

摘要:

From the prophecies of the Ancients to the crystal‐gazing of the Moderns, man's urge to know his fate has been in opposition to the wisdom of a Providence that mercifully cloaks the future and reduces the outlook largely to speculation; and flood‐forecasting, in the general sense, is an example of this characteristically human effort to foretell events. The purpose of this discussion is to consider modern man's attempt to organize his knowledge of floods in order to foresee (1) the extreme experience to which his flood‐control works will be subjected, (2) the number and magnitude of the lesser floods that will probably occur, and (3) the approach of the individual

ISSN:0002-8606    

DOI:10.1029/TR020i002p00187

年代:1939

数据来源: WILEY

摘要:

Storage of water in the form of snow makes possible an advance determination of the probable water‐supply. Forecasts may be expressed in terms of acre‐feet for specific periods, or in terms of discharge in cubic feet per second for specific dates. Forecasting the total supply over a given period, on the basis of snow‐surveys, is now well established, but a determination of the probable discharge for any specific date during the critical runoff‐season is more difficult. On streams having ample surface‐storage, a seasonal forecast is all that is necessary. However, where the water cannot be stored, but must be used as it comes, it is extremely valuable to know the time of its o

ISSN:0002-8606    

DOI:10.1029/TR020i002p00194

年代:1939

数据来源: WILEY

摘要:

(1) It has been recognized by the Federal Government, within recent years, that destructive floods upon the rivers of the United States constitute a menace to national welfare. The River and Harbor Acts of March, 1925, and January, 1927, resulted in what are generally known as H.D. “308” reports covering the principal drainage‐systems in the United States. The “308” reports were followed by Flood‐Control Acts, authorizing projects throughout the United States, such as reservoirs, levees, channel‐improvements, river cut‐offs, diversions, debris‐basins, flood‐ways, and flood‐walls. In addition to the authorization of definite flood‐control projects, the Acts provide for preliminary examinations and surveys for flood‐control at approximately 440 localities throughout the country. Prosecution of this work is by the War Department, under the supervision

ISSN:0002-8606    

DOI:10.1029/TR020i002p00195

年代:1939

数据来源: WILEY

摘要:

Federal policy and program—Congress, in recognition of recurrent flood‐history affecting the general public interest, has projected a long‐range program and policy for the control of destructive floods. It has declared that such protection is a public responsibility and therefore a proper activity of the Federal Government in cooperation with the States and local public agencies. In the enabling flood‐control legislation of 1936, the amendment of 1937, and the Flood‐Control Act of 1938, Congress has prescribed procedures for the establishment of the national flood‐control program. These enactments are the authorities which direct the Secretary of War and the Secretary of Agriculture to carry out an integrated and correlated program for which expenditures have been authorized over a five‐year period, and appropriations made available for the fiscal years

ISSN:0002-8606    

DOI:10.1029/TR020i002p00203

年代:1939

数据来源: WILEY