摘要:

The major development in this paper is a method for determining rates of water movement within the soil profile on watersheds under natural conditions. The method uses rainfall rates or infiltration curves as the supply of water to the soil and field measurements of soil‐moisture changes. The major objective was the determination of relationships between infiltration, soil moisture, and surface runoff on watersheds representing two soil types of different hydrologic characteristics and in three vegetal covers. Information was developed on the effect of soil properties and land use upon such relationships.The amounts of water taken up by successive inch increments of soil depth during storms were established by soil‐moisture measurements. The time required for each of these amounts to accumulate was determined from the accumulated infiltration curve, or from rainfall minus interception storage when no runoff occurred. Analyses indicate the velocity of water moving through the soil under various conditions, particularly differences in available storage space. Transmission rates or velocities as high as ten in/hr were obtained for the topsoil or plow layer. For a number of storms, water reached the subsoil shortly after runoff began. After water reached the subsoil, the rates at which the remaining topsoil storage was exhausted were deducted from the infiltration rates and the percolation rates at the bottom of the topsoil established. Percolation rates did not exceed 0.60 in/hr. Using percolation rates as the supply, transmission rates through the subsoil were established. Transmission rates did not exceed 1.50 in/hr for the subsoil. As saturation was approached, rates of infiltration decreased until they approached a constant rate at saturation and the low transmission rates in the subsoil became the controlling factor. Infiltration curves, percolation curves, and transmission rates are illustrated and findings interpreted in the light of soil properties and land

ISSN:0002-8606    

DOI:10.1029/TR030i001p00075

年代:1949

数据来源: WILEY

摘要:

A method is presented for estimating the amount of delayed runoff due to accumulated snow on a drainage area. Although the study as presented pertains to estimating the water supply in the Tuolumne River drainage area, the general principles of the method apply to all Sierra streams. The precipitation‐runoff relationship that is discussed forms the practical working tool of the engineer who must efficiently operate reservoirs for the multiple purpose of water supply, power, irrigation, and flood contro

ISSN:0002-8606    

DOI:10.1029/TR030i001p00089

年代:1949

数据来源: WILEY

摘要:

A need exists for a reliable method of establishing a reference plane of flood runoff for comparison of degree of protection provided by flood‐control projects. This paper presents a method of establishing such a reference plane for the Sacramento‐San Joaquin Basin based on a statistical study of the flood runoff which has been recorded in California and the correlation of flood runoff with various stream‐basin characteri

ISSN:0002-8606    

DOI:10.1029/TR030i001p00098

年代:1949

数据来源: WILEY

摘要:

In a study undertaken by the writer in the central Appalachians, an attempt is being made to determine the effect which tectonic action—diastrophism—may have had on the original stratigraphic thicknesses of sedimentary rocks. This study, of which this account is merely an early progress report, has been initiated at the suggestion and under the most helpful guidance of Ernst Cloos.The Paleozoic rocks with which the work is concerned are considered to be sedimentary in character, although they have been folded and fractured and rearranged to a greater or lesser degree. The major part of this problem deals with the cleavages which are developed in these folded Paleozoic rocks. By coming first to know, as nearly as possible, just what happened to the rock components to produce a given cleavage, inferences as to the effects on thicknesses of such changes as have produced the cleavage, should be more correctly drawn. The examination of the cleavage thickness relationships in more or less completely exposed folds in the field is, perhaps, just as important as the reliance on such inferences. Deductions based on observations of small folds are assumed to hold for large folds which are never completely expo

ISSN:0002-8606    

DOI:10.1029/TR030i001p00116

年代:1949

数据来源: WILEY

摘要:

In view of the development of the geodetic triangulation of Mexico, in which it has not always been possible to follow along parallels and meridians, due principally to the irregularity of the State boundaries in the Republic and to the rugged character of its terrain, we are working actively to finish a project of first order which comprises the arcs represented in Figure 1, in which the parts finished up to the end of 1947 are marked in solid black, and the part which is planned and in progress at the present time is marked with hachures.

ISSN:0002-8606    

DOI:10.1029/TR030i001p00119

年代:1949

数据来源: WILEY

摘要:

One of the first operations of the Geodetic Survey of Canada after its inception in 1905 was the establishment, on a local datum, of the Dusable‐Haldimand net extending from east of Montreal to slightly west of Kingston. In 1913, this net was connected in the Montreal area to the stations, Royal and Bellevue, comprised in the United States Coast and Geodetic Survey network. This connection was of great importance, as it made possible the establishment of the Canadian triangulation the North American datum, which had been adopted that same year by Canada, the United Kites, and Mexico.From this beginning, a primary net was extended northeasterly along the St. Lawrence River (see Fig. 1). till in 1923 the triangulation was terminated in the neighbourhood of Anticosti Island in the Gulf of St. Lawrence. Three of the stations comprised in this net, located near the eastern tip of Gaspé County, Quebec, were then used as a basis for the extension of a net towards the south. This net was projected through eastern New Brunswick to terminate in 1926 at the stations Shepody and Salem, which had already been comprised in the net of Bay of Fundy. The junction of the two primary nets at Shepody‐Salem marked one of the first loop closures of Canadian geodetic triangula

ISSN:0002-8606    

DOI:10.1029/TR030i001p00123

年代:1949

数据来源: WILEY

摘要:

The year 1947 marked a gradual return to normal conditions throughout the scientific world; particularly in the United States was this noticeable.The member stations of the Jesuit Seismological Association whose activities had been largely disrupted by the War not only resumed their normal operations but were taking steps to improve.

ISSN:0002-8606    

DOI:10.1029/TR030i001p00127

年代:1949

数据来源: WILEY

摘要:

For this report it was suggested that, if the committee members did not have current research progress to report, they might contribute their comments on the following topic: Gains in water content of soil or snow during rainless periods. The results are presented below.In some localities where fogs are prevalent, drip from the trees may be an important source of water for the soil when no precipitation is recorded in rain gage in a standard exposure. An outstanding example comes from the Cascade Head Field Station of the Pacific Northwest Forest Experiment Station, which is located close to the Oregon coast. During an aggregate of 142 foggy days, when the precipitation recorded in a, standard gage amounted to 25.19 inches, the average of the catch in three gages under a dense stand of sitka spruce and western hemlock 150 ft high, amounted to 35.42 inches. The excess of 11.23 inches, or 0.08 inch per day, resulted from fog drip from the trees.

ISSN:0002-8606    

DOI:10.1029/TR030i001p00131

年代:1949

数据来源: WILEY

摘要:

Under the discussion of wave period, the author states, “Periods of surface waves are to be expected to be lower than those recorded at or near the bottom.” This statement is true, but it should be supplemented by a statement to the effect that, by placing a pressure pick‐up unit below the sea surface, pressure fluctuations due to the shorter period waves are inappreciable or non‐existent because of hydro‐dynamic filtering. Thus, only the pressure fluctuations from the longer period waves are present to activate an underwater pressure pick‐up unit. The relationships between the period of subsurface pressure‐fluctuations and the average period of the combined wind waves and swell observed at the surface given by the author for stations at Cuttyhunk and Bermuda were merely a function of the depth of the instruments and the wind waves and swell that existed at the time of the observations. With different depths of instrument and different wave conditions, the filtering effects would be different; hence the ratio of periods as observed at the surface and recorded by an underwater instrument would be different. Without explanatory supplementary statements on filtering action accompanying wave motion, it is believed that the casual reader would be led to the erroneous belief that a certain single wave train would have a different period whether observed at the surface or belo

ISSN:0002-8606    

DOI:10.1029/TR030i001p00134-1

年代:1949

数据来源: WILEY

ISSN:0002-8606    

DOI:10.1029/TR030i001p00140

年代:1949

数据来源: WILEY