bluuebunny/crossref_metadata_2025 huggingface dataset:
Diurnal variation of the atmospheric potential‐gradient at Penalosa, Kansas
Authors: Wait G. R.
Published: February 2008

Atmospheric potential‐gradient data from only a small number of American stations have been published. At but four of these was the character of the observations such as to furnish a diurnal‐variation series. Three of the stations were either on or near the Atlantic coast while the remaining station was near the Pacific coast. There exists no published diurnal‐variation series from a station situated well in the interior of the Continent. Such a station was consequently established at Penalosa, Kansas, near the geographical center of the United States and records of the potential gradient secured during a portion of August 1929.

Diurnal‐variation results for the potential gradient at some land stations in the past may appear to have been seriously affected by a systematic variation and especially in the two ‘factors insulation‐leak and atmospheric pollution. Considerable care was exercised therefore both before and throughout the series to insure these factors would be negligibly small in the present investigation. The resulting diurnal‐variation curve when plotted on Greenwich meridian time shows very close agreement with one obtained by the Carnegie over the Pacific Ocean the following month as well as with the one for the period August, to October from data obtained on Cruises IV, V, and VI of the Carnegie.
Twenty‐five years' work on the polar aurora
Authors: Störmer Carl
Published: February 2008

In the following pages I will try to give an extract of some lectures given at English universities during the spring of 1930 regarding my work on the polar aurora during the last twenty‐five years.

As to the different forms of aurora polaris, reference may be made to the photographic atlas of aurora published by the International Union of Geodesy and Geophysics (1).
The geographical distribution of magnetic disturbance
Authors: Wallis W. F.
Published: February 2008

A discussion at the Department of Terrestrial Magnetism of the magnetic results obtained by the two MacMillan arctic expeditions of 1921–22 and 1923–24, and a comparison of these results with those from several other stations, indicate that during magnetic storms the greatest disturbance occurs in the region of the zone of maximum auroral frequency, and that there is a close correlation between the curves of magnetic activity and auroral frequency when both are plotted in relation to magnetic latitude. A study of the propagation of different types of magnetic disturbance indicates that all types are not propagated with the same velocity. Possible causes of terrestrial magnetic disturbances are discussed.
Louis Agricola Bauer and terrestrial magnetism
Authors: Nippoldt A.
Published: February 2008

On April 12, 1932, the fruitful and active life of Louis Agricola Bauer, director emeritus of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington, came to an end. Seldom has it been given to an investigator to call into existence, in his own branch of science, an organization of such wide interests and on so large a scale, as Bauer did in his chosen field—terrestrial magnetism and electricity. In an exemplary manner, he placed in the service of science, a nature richly endowed with ideas and with the theoretical as well as practical ability. I esteem it a great honor, at the request of the editor of this JOURNAL which Bauer founded, to present on behalf of international geophysical science, a picture of the activities and achievements of this investigator, by repeating the words which I published elsewhere some seven years ago on the occasion of the sixtieth birthday of our departed friend.
Studies on the magnetic conditions in the region between Gjöahavn and the Magnetic Pole during the year 1904
Authors: Wasserfall K. F.
Published: February 2008

Introduction—Actual observations of geographical coordinates at the Magnetic North Pole have been made on only two occasions. The geographical coordinates are latitude 70° 05′ north in longitude 96° 46′ west as determined by James Ross in 1831 and 70° 30′ north in longitude 96° 30′ west as determined by Roald Amundsen in 1904. Ross's coordinates were revised by Nippoldt several years ago [see 1 of “References” at end of paper], who found them more or less satisfactory, while Amundsen's values have been accepted as above as given in the paper containing the results of the Gjöa Expedition [2].

Because of the small number of stations by the Gjöa Expedition it was difficult to decide whether fixing of the geographical coordinates of the Pole could be justified. In their discussion, Steen, Russeltwedt, and Wasserfall agreed on the following statement [2]: “From what has been said it is clear that we cannot form a decided opinion as to the exact coordinates of the Pole, but we may nevertheless be allowed to hazard the following assertion as more or less probable.” As one of the authors, I may confess that because of this first decision, the material itself was not sufficiently and critically examined. Recent investigation shows this to be the case and has resulted in the conclusion, that the available material is such that it actually makes possible a fairly exact determination of the main Pole‐point. The facts which may be considered to justify a new determination and an outline of the reasoning employed are given in this paper.
Collected volumes of information on terrestrial magnetism and electricity
Authors: Pushkov N. W.
Published: February 2008

Beginning with the year 1935 the Magnetic Observatory of Sloutsk has published periodically “Collected volumes” of information on terrestrial magnetism and electricity. At the present time four volumes have already appeared and the fifth volume is now in the press.

One of the chief objects of these volumes is to inform, as quickly and fully as possible, the scientists working in terrestrial magnetism and electricity and the allied sciences of all essential scientific discoveries concerning terrestrial magnetism and electricity. In conformity with this purpose the “Collected volumes” contain not only original articles but also reviews and bibliographical indexes of papers published in Russian and other languages.
Some Early Contributions to the History of Geomagnetism—VII
Authors: Harradon H. D.
Published: February 2008

Joäo de Castro was a Portuguese naval commander and explorer, born in Lisbon in 1500, the son of Alvaro de Castro, governor of that city. As a young man he distinguished himself in the campaigns against the Moors in North Africa. In 1545 he was sent to the “Indies” with six ships where he overthrew Mahmud, King of Gujarat, relieved the besieged town of Diu, and achieved a number of other military successes.1 In 1547 he was appointed Viceroy of India by Joäo III, but soon after receiving his full commission he died at Ormuz, June 6, 1548.2
Chapters in the history of terrestrial magnetism
Authors: Mitchell A. Crichton
Published: February 2008

1—It is generally recognised that the early history of the simpler phenomena of Magnetism was confined at first to the progress made within two well‐defined, but widely separated, areas. One of these lay in the eastern Mediterranean, notably in Greece and Egypt, and for this the extant sources of information, scanty though they are, provide evidence of a reliable character. The other, possibly earlier, was in the Far East, principally China, and for this the record is of a less satisfactory kind. As far as the evidence relating to each can be trusted, it would appear that the course of development of the science followed different lines in these two areas.
The secular variation of the direction of a freely suspended magnetic needle at Callao, Valparaiso, Shanghai, Hong‐Kong, and Sydney
Authors: Littlehales G. W.
Published: February 2008

The object of this paper is part of a general purpose to collect and present from time to time the recorded observations of the magnetic declination and dip at stations in all parts of the world, with a view of amplifying the investigations that have already been made into this subject and thus preparing the way for throwing more light upon the question of the periodic nature of the secular variation of the magnetic needle.

The collections of data relating to Callao, Valparaiso, Shanghai, Hongkong, and Sydney are here presented together with the results obtained by adapting formulas of interpolation to the observations. And the curves traced out by the north end of the needle upon planes tangent to the sphere in latitudes corresponding to the mean values of the dip at the various stations are also given in accordance with the method employed by Dr. L. A. Bauer. Attention is especially invited to the new case presented at Sydney, where the needle has receded, since 1860, over the path along which it passed prior to that year.
Ueber die Fehler bei erdmagnetischen Messungen
Authors: Wild H.
Published: February 2008

Jede Bestimmung der Elemente des Erdmagnetismus stellt eine physicalische, bei der Declination auch theilweise eine astronomische Messung dar, und man darf daher erwarten, dass, wie es bei diesen üblich ist, so auch dort nicht einfach bloss das Resultat der Messung, sondern auch die Sicherheit desselben—mittlerer oder wahrscheinlicher Fehler einer einzelnen Messung oder auch des Resultats aus mehreren gleichartigen Messungen—mitgetheilt werde. Es gilt dies sowohl von den absoluten magnetischen Messungen, als auch von den blossen Variationsbeobachtungen der erdmagnetischen Elemente. Diese Sicherheit wird je nach den Umständen, über die man nicht immer unbedingt verfügen kann, wie z. B. die Grösse der aufzuwendenden Mittel für Personal und Instrumente, die Art der zur Disposition stehenden Idealitäten, u. s. w. eine sehr verschiedene sein; aber ob sie nun grosser oder kleiner sei, in allen Fällen wird es für die Benutzung der betreffenden Daten und insbesondere für ihre Vergleichbarkeit mit ändern nothwendig sein, da&s man über den Grad der Genauigkeit oder Zuverlässigkeit derselben vom Beobachter unterrichtet werde.

Angesichts nun der Thatsache, dass nicht bloss bezüglich vieler vereinzelter magnetischer Messungen, sondern sogar von den Beobachtungen der Mehrzahl der magnetischen Observatorien keine oder nur ungenügende Angaben über die Sicherheit der Resultate vorliegen, dürfte es wohl zeitgemäss sein, einmal des Nähern auf alle die nähern Aufschlüsse hinzuweisen, welche der Beobachter von seinen Messungen zu geben hat, damit die Genauigkeit des Resultats befriedigend festgestellt werden kann. Eine solche Erörterung wird vielleicht geeignet sein, die Differenzen etwas aufzuklären, welche man z. B. bei der Vergleichung der Intensitätsmessungen mit verschiedenen Instrumenten gefunden hat.
On the investigation of hidden periodicities with application to a supposed 26 day period of meteorological phenomena
Authors: Schuster Arthur
Published: February 2008

1. Obvious and hidden periodicities. A variable quantity may show periodic changes which become obvious as soon as a sufficient record has been obtained; such are the semi‐diurnal changes of the tides, or the eleven years recurrence of sunspot maxima. We may call these obvious periodicities. Most often, however, small periodic variations are hidden behind irregular fluctuations, and their investigation then becomes a matter of considerable difficulty.
Steady state water flow in a saturated inclined soil slab
Authors: Klute A. , Scott E. J. , Whisler F. D.
Published: February 2008

Equipotential and isobar patterns were calculated for the case of flow in a saturated inclined soil slab resting on an impermeable base. Two situations were analyzed, one with both upper and lower ends of the slab closed to flow and another with only the upper end closed. Most of the water flowing through the slab enters and leaves in a surface region near the ends of the slab. For slope length‐to‐depth ratios greater than about 10, the total flow can be estimated quite closely by treating the slab as an inclined one‐dimensional flow system.
Rates of vertical groundwater movement estimated from the Earth's thermal profile
Authors: Bredehoeft J. D. , Papaopulos I. S.
Published: February 2008

An analytical solution is developed describing vertical steady flow of groundwater and heat through an isotropic, homogeneous, and fully saturated semiconfining layer. A type‐curve method for estimating groundwater velocities from temperature data is presented.
An optimization scheme for gaging
Authors: Fiering Myron B
Published: February 2008

The conjunctive use of nonlinear integer programming and principal component analysis is suggested for specification of a constrained optimal gaging program whose objective is to define efficient estimates of the several annual means. The assumptions in the analysis are restrictive; data from thensites are presumed to be available forn1years, andn2years of additional gaging are contemplated. The observations are presumed to derive from a multivariate normal population with no serial correlation. The method specifies which sites from among thencandidates should be continued and which should be estimated by linear regression. Although the discussion is directed toward hydrologie applications, it should be recognized that the technique is generally applicable to sampling surveys.
Viscous model study of drain spacing on sloping land and comparison with mathematical solution
Authors: Guitjens J. C. , Luthin J. N.
Published: February 2008

Schmid and Luthin have proposed a mathematical solution for draining sloping land by evenly spaced ditches that reach to the impermeable layer. Their theory was based on solutions of the Boussinesq equation for the water table in equilibrium with rainfall. The Dupuit‐Forchheimer assumptions inherent in the Boussinesq equation lead to an undetermined error in the results. A Hele‐Shaw model used to solve the same problem indicated that the error due to the Dupuit‐Forchheimer assumption was small for slopes less than 30%. For slopes greater than 30% the mathematical solution gave ditch spacings that were too great.
Water from low‐permeability sediments and land subsidence
Authors: Domenico P. A. , Mifflin M. D.
Published: February 2008

Seepage pressures are part of the neutral or nondeformative stresses acting in a groundwater basin. The reduction of these pressures gives rise to a stress transfer from neutral to effective. The increase in effective stresses is, exclusively responsible for measurable deformations of the land surface. The amount of land subsidence or groundwater recovery from compressible confining layers depends upon the specific storage of the strata and the average head change within them. Expressions for the specific storage are obtained from both consolidation theory and conservation principles of compressible flow. Average head changes are identified on a depth‐pressure diagram in terms of head changes in adjacent aquifers and are referred to as ‘effective‐pressure areas.’ The geometry of the effective‐pressure area is shown to depend upon the thickness of the compressible strata, the magnitude of artesian pressure decline, the manner in which the basin is developed, and time. These factors are embodied in equations that quantitatively describe the release of stored water from compressible confining layers resulting from their vertical compression in areas of land subsidence.
Stochastic branching processes and the law of stream orders
Authors: Scheidegger Adrian E.
Published: February 2008

The law of stream orders can be deduced by assuming that river junctions are subject to a statistical branching process. (Key words: Drainage basin characteristics; river classification; statistics.)
Moisture movement in soils under temperature gradients with the cold‐side temperature below freezing
Authors: Hoekstra Pieter
Published: February 2008

Moisture movement to a freezing front in an unsaturated porous medium of Fairbanks silt was measured by γ‐ray attenuation. It was shown that the presence of an ice phase greatly enhances the amount of moisture transfer under temperature gradients. The chemical potential of soil water in the frozen soil as a function of temperature is calculated. The chemical potential of unfrozen absorbed water in frozen soils, if in equilibrium with ice, is independent of total water content (unfrozen water plus ice). Consequently, no equilibrium moisture content distribution is reached, and water content in the frozen soil changes continuously. Moisture flow in the frozen soil takes place under temperature gradients through the films of unfrozen water. Since the thickness of the unfrozen films decreases with temperature, the rate of water transport also decreases rapidly with decreasing temperature below 0°C. (Key words: Frost; soil moisture.)
Darcy's law in saturated kaolinite
Authors: Olsen Harold W.
Published: February 2008

Data obtained with a new laboratory technique for measuring the hydraulic conductivity of saturated clays show that Darcy's law is obeyed at low gradients in saturated kaolinite over a wide range of porosities. The new technique involves producing arbitrary constant flow rates through a rigidly confined clay sample, using a multispeed syringe pump, and measuring the gradients induced thereby with a differential pressure transducer. This procedure avoids the errors in the conventional technique that arise from atmospheric contamination and from the long time intervals needed to obtain measurable flow rates. The results presented, together with the previous evidence, suggest that Darcy's law is valid in many saturated natural clays and clayey sediments, but that exceptions may occur in extremely fine‐grained clays and also where high gradients are present in shallow, unconfined sediments or in granular soils containing small amounts of clay. (Key words: Permeability; porous mediums.)
Redistribution of soil water after infiltration
Authors: Biswas T. D. , Nielsen D. R. , Biggar J. W.
Published: February 2008

The redistribution of soil water after the cessation of infiltration in three agricultural soils was analyzed experimentally in the laboratory. It was found that the rate of redistribution within the soil profiles depended upon the initial depth of wetting and the soil water content‐soil water pressure‐capillary conductivity relations. The results are discussed in relation to measured and predicted profiles of inert porous mediums. (Key words: Infiltration;irrigation; soft water)
Hydrology of a Karst Area in east‐central West Virginia
Authors: White William B. , Schmidt Victor A.
Published: February 2008

Movement of groundwater through a maturely karsted limestone aquifer in Pocahontas County, West Virginia, was studied by dye‐tracing and extensive underground mapping techniques. The aquifer consists of 400 feet of flat‐lying Mississippian Greenbrier limestone. The drainage basin of Hills Creek is completely enclosed by clastic rocks, and discharge is by subterranean flow. The Swago Creek underground drainage is quite unrelated to surface drainage, and drainage lines cross major surface divides. Underground divides have been mapped and may occur under valleys as well as under ridges. The water table is remarkably flat, with abrupt breaks in slope only near the margins of the area under a rugged surface topography whose relief exceeds 2000 feet. The surface topography is not reflected in the karst water table, and free‐surface flow often occurs as much as 1000 feet below the land surface. Even minor insoluble beds are capable of perching tributary underground streams as much as several hundred feet above base level. Underground flow takes place along hydraulic gradients that point to the major base‐leveling stream of the area, the Greenbrier River, rather than to surface valleys. (Key words: Drainage basin characteristics; geomorphology; groundwater; West Virginia)
Theoretical analysis of regional groundwater flow: 1. Analytical and numerical solutions to the mathematical model
Authors: Freeze R. Allan , Witherspoon P. A.
Published: February 2008

It is possible to represent steady‐state regional groundwater flow in a three‐dimensional, nonhomogeneous, anisotropic basin by a mathematical model. The numerical finite‐difference approach can be used to solve the general case; the analytical separation of variables technique is restricted to two‐dimensional layered mediums. The numerical method is more versatile, mathematically simpler, and well suited to computer oriented methods of data storage. Computer results are in the form of plotted potential nets from which flow patterns can be constructed.
Grain size distribution and its effect on the permeability of unconsolidated sands
Authors: Masch Frank D. , Denny Kleber J.
Published: February 2008

Since permeability is the measure of the ease with which water moves through aquifer material, certain relationships must exist between permeability and the statistical parameters that describe the grain size distribution of the porous mediums. Experimental studies to investigate these relationships consisted of systematic variation of the values of the statistical parameters and evaluation of the corresponding permeabilities of the samples. The parameters investigated included measures of the average size, dispersion, skewness, peakedness, and modality of the sample distributions. Several graphs were developed that related permeability to the various statistical parameters. On the basis of these plots a group of curves was defined to predict laboratory permeability values for aquifer samples with random statistical distribution. This set of prediction curves incorporated only the average size and dispersion, because these parameters best described the relationship between permeability and the grain size properties of the porous mediums. These prediction curves were then used to determine the laboratory permeability coefficients for a group of samples obtained from a natural aquifer, and the results were compared with actual permeability values obtained from laboratory tests.
An instantaneous profile method for determining the hydraulic conductivity of unsaturated porous materials
Authors: Watson K. K.
Published: February 2008

The hydraulic conductivity‐water content relationship, as used in the differential equation describing unsteady flow in unsaturated porous materials, is determined from measurements obtained during the drainage of an initially saturated sand column. The approach utilizes instantaneous profiles of the macroscopic flow velocity, the potential gradient, and the water content. The derived relationship exhibits a direct proportionality between the instantaneous velocity and the corresponding potential gradient, thus lending strong support to the contention that Darcy's Law is applicable to flow in unsaturated porous materials of the size range considered in this study.
The role of universities in water resources education: The social sciences
Authors: Hufschmidt Maynard M.
Published: February 2008

The future role of the social sciences in the specialist education of graduates who will work in the field of water resources is examined. The current comparatively small participation of university social science departments in such training is reviewed briefly, and proposed methods of interdisciplinary involvement are suggested, such as water resources topics for theses within the social sciences, service courses in a social science discipline for engineering and natural sciences students, and social science participation in water‐resource‐oriented seminars. Specific suggestions are advanced for participation of the social sciences in a water resources study program involving the long‐term interdisciplinary collaboration of social scientists with natural scientists and engineers in an integrated series of graduate courses and research seminars dealing with water resources problems, issues, and policies. A partial list of relevant areas and courses within the social sciences is proposed for discussion.
The impact of price on residential water demand and its relation to system design and price structure
Authors: Howe Charles W. , Linaweaver F. P.
Published: February 2008

This paper formulates models of residential water demand and estimates the relevant parameters from cross‐sectional data. For the first time, it has been possible to differentiate not only between domestic (inside) and sprinkling uses but also among metered, flat‐rate, septic tank, and apartment areas. The major findings are: (1) domestic demands are relatively inelastic with respect to price; (2) sprinkling demands are elastic with respect to price, but less so in the west than in the east; (3) maximum day sprinkling demands, so important to system design, are inelastic in the west but relatively elastic in the east. The findings indicate that the elasticity of total demand, which this and other studies have found to be about −0.4, is a weighted average of the domestic and sprinkling elasticities. Longer term adjustments to price are empirically investigated, and the role of demand functions in pricing and system design is discussed.
Depletion of flow in right‐angle stream bends by steady wells
Authors: Hantush Mahdi S.
Published: February 2008

The flow of a stream that is hydraulically connected to an aquifer can be reduced considerably by nearby pumping wells. Pumping such wells will either increase the infiltration from the nearby streams or decrease the natural groundwater flow that would have discharged into the streams if the wells had not been pumped, or effect both processes at the same time. The depletion of the stream flow is an increase to the perennial yield of the sand. Consequently, greater supplies of water can be obtained than would be available as groundwater alone in such systems. Natural as well as artificial streams meeting at approximately right angles are not uncommon in nature. Irrigation and drainage canals, and streams having a trellis drainage pattern, are examples of such an occurrence. Wells for domestic as well as for irrigation use are often installed near such streams. Rational estimates of the rate of depleting such streams by the nearby pumping wells are therefore of practical interest. Formulas for estimating the rate and volume of stream depletion in such systems are developed in terms of extensively tabulated functions.
Carbon 14 ages and flow rates of water in Carrizo Sand, Atascosa County, Texas
Authors: Pearson F. J. , White D. E.
Published: February 2008

Ages of groundwater can be determined from the carbon 14 content of the carbonate dissolved in the water. The carbon 14 is derived from plant‐produced CO2 in the soil of the recharge area and is usually diluted by carbon 14‐free carbonate dissolved from carbonate minerals in the soil and in the aquifer. Techniques based on the ratios of the stable carbon isotopes and on the over‐all carbonate chemistry of the water can be used to correct for this dilution and to allow the calculation of true water ages. Water samples from wells in the Eocene Carrizo Sand in Atascosa and adjacent counties, Texas, were dated by this method. The ages of the water samples ranged from 0 years at the outcrop to 27,000 years 35 miles downdip. Based on the carbon 14 ages, the water velocities were about 8 feet per year 10 miles from the outcrop and 5.3 feet per year at 31 miles. Flow rates calculated from available hydrologic data are in agreement with carbon 14 results.
Observations on Title II, Water Resources Planning Act
Authors: Morgan Horace P.
Published: February 2008

A year has elapsed since the Water Resources Planning Act, Public Law 89‐80, 89th Congress, S. 21, was approved on July 22, 1965 [Water Resources Planning Act, 1965].

It is too early to assess results obtained from the Act. But it appears timely to make some observations on one aspect of the legislation.
Control levels for quantitative evaluation of weather modification attainments
Authors: Markovic Radmilo D.
Published: February 2008

There are three basic control levels from which the quantitative (statistical) evaluation of weather modification (cloud seeding) attainments can be considered, corresponding to three particular stages in the general hydrologic cycle: cloud phenomena, precipitation, and river flow control levels. The cloud phenomena level of control is suitable for qualitative (physical) rather than for quantitative (statistical) evaluation of weather modification attainments. The precipitation level of control may be used for both qualitative and quantitative evaluations. However, the inaccuracy involved in single measurements of precipitation under different environmental conditions and in the determination of mean areal precipitation makes this level of control unreliable for the quantitative evaluation of weather modification attainments at present. The river flow control level has been shown to be suitable and promising, accurate, and reliable for practical purposes, and it is, therefore, highly recommended for use in the quantitative evaluation of weather modification attainments. (Key words: Precipitation; atmosphere; weather modification; runoff)
Slope length of claypan soil affects runoff
Authors: Jamison V. C. , Peters D. B.
Published: February 2008

Measurements of runoff after prolonged irrigation of grass plots on a claypan soil (Mexico silt loam) showed that recession yields per unit area increased with slope length. Yields from slopes of lengths varying from 76 to 323 feet indicated return flow (‘interflow’) during runoff recession of at least 0.1 inch from the longer plots. During a simulated wet season using irrigation to supplement rainfall in the summer of 1965, per unit area yields were greatest for long plots, except for small events or events of long duration. The seasonal yield was 1.69 inches, or about 19% more from the long than from the short plots. Hydraulic conductivity measurements indicate that the predominant path of interflow is in the upper inch or two of the soil surface. However, soil moisture content and hydraulic pressure gradient changes during recession runoff indicated that there may be an interflow contribution from the loessal soil layer between weathered till and claypan. (Key words: Runoff; soil moisture; infiltration)
Insecticides in tile drainage effluent
Authors: Johnston William R. , Ittihadieh F. T. , Craig Kenneth R. , Pillsbury Arthur F.
Published: February 2008

Drainage effluent from systems located on irrigated land in the San Joaquin Valley of California was analyzed for insecticide residues. Only relatively small quantities of chlorinated hydrocarbon residues were found in tile drainage effluent, but higher concentrations were found in effluent from open drains where both surface and subsurface drainage waters were collected. Traces of residue were found in the irrigation water applied to tile drained farms. When the concentration factor is considered, i.e., depth of irrigation water applied/depth of drainage water removed, on a unit baas, the total quantity of insecticide residue in tile drainage effluent does not exceed and is generally less than the total quantity of residue applied in the irrigation water. Tailwater, or surface runoff, contained from 7 to 12 times as much residue as the applied water when DDT was applied to the land and as much as 85 times more residue than the irrigation water when Lindane was applied to the land. Relatively large concentrations of residue were found in the surface soil of the area studied, even where no pesticides had been applied directly to the soil. (Key words: Drainage; groundwater; insecticides; quality of water)
Infiltration in sands and its relation to groundwater recharge
Authors: Smith W. O.
Published: February 2008

The unconsolidated sediments that permit substantial infiltration are sands, silts, and gravels. Several experiments on the mechanics of infiltration with sands and glass beads involve one or the other of the following: a bulk mass of liquid originating at the surface of the medium in a stream ranging from a thin thread to a sizable flow; a sheet of liquid laid entirely across the surface of the medium; and, finally, drops of liquid similar to raindrops falling on the surface. All result in essentially the same picture, that of a drop of liquid falling in a capillary tube. The water moves as a bulk mass. There may, be some film flow locally, but it is relatively insignificant. During the process of infiltration each element of a sand, silt, or gravel extracts enough water to satisfy its capillary requirements, to the extent that they are not satisfied by water already present from previous infiltrations. In gravel capillarity is usually negligible. The retained water per unit mass of dry soil is known as specific retention and may also be called field capacity. The balance of the infiltrating water proceeds downward until it either is totally absorbed by the sand or reaches the water table as recharge. The equations of capillarity are reviewed from a thermodynamic standpoint and are given in both differential and integral form. It is concluded that infiltration is a downward movement of water in bulk form, under ordinary hydraulic laws subject only to the reduced or otherwise altered pressures caused by capillarity within the bulk mass of liquid. Film flow appears to be confined to local flow to contact points, which situation is compatible with the condition that the free, energy Fs, of capillary surfaces in a sand, given by Fs = ∫ σ dO, where σ is the surface tension of water and dO is an element of the capillary surface, must be at a minimum. The results when applied to the infiltration process agree with field data. (Key words: Hydraulics; infiltration in sediments; groundwater)
Theoretical analysis of regional groundwater flow: 2. Effect of water‐table configuration and subsurface permeability variation
Authors: Freeze R. Allan , Witherspoon P. A.
Published: February 2008

Details of steady‐state flow in regional groundwater basins can be investigated using digital computer solutions of appropriately designed mathematical models. The factors that must be considered are: (1) ratio of depth to lateral extent of the basin; (2) Watertable configuration; and (3) stratigraphy and resulting subsurface variations in permeability. The results of this study provide a theoretical basis for the following properties of regional flow systems: (1) groundwater discharge will tend to be concentrated in major valleys; (2) recharge areas are invariably larger than discharge areas; (3) in hummocky terrain, numerous sub‐basins are superposed on the regional system; (4) buried aquifers tend to concentrate flow toward the principal discharge area, have a limiting effect on sub‐basins, and need not outcrop to produce artesian flow conditions; (5), stratigraphic discontinuities can lead to distributions of recharge and discharge areas that are difficult to anticipate and that are largely independent of the water‐table configuration. (Key words: Groundwater; computers, digital; drainage basin characteristics)
Note on ‘The accuracy of the prediction of floods of high return period’
Authors: Nash J. E. , Amorocho J.
Published: February 2008

While pursuing further studies on this subject our attention has been directed by the reference in the WMO ‘Guide to Hydrometeorological Practices’ [1965] to the work of Kaczmerek [1957], which was unknown to us at the time of writing the above paper [Nash and Amorocho, 1966]. In Kaczmerek's work, a formula for the standard deviation of estimates of the magnitude of a flood of given return period is derived. This formula may be written in our notation as

urn:x-wiley:00431397:media:wrcr210:wrcr210-math-0001
It agrees with equation 14 of our paper, except for the coefficient of K.

The difference between the two formulas arises in the evaluation by us of the coefficient of correlation between the mean and the standard deviation of samples drawn from a double exponential universe. Using a Monte Carlo process, we obtained a value of 0.56 for this quantity. A value of 0.62, which is not inconsistent with our results, would render the two formulas identical. Kaczmerek's treatment of the problem, and his derivations, were entirely analytical and, we believe, are superior to ours. It is gratifying, however, that we obtained such close agreement with his results by a completely different approach.
Design philosophy, specifications, and implications of ‘Hydro’, A pilot computer language for hydrology and hydraulic engineering
Authors: Bugliarello G. , Mcnally W. D. , Gormley J. T. , Onstott J. T.
Published: February 2008

The increasingly pressing needs for effective means of analyzing and controlling water resources problems make it imperative to use to the fullest advantage the capabilities of computing machines. Determination of the optimal interface between man and computer in water resources is a many‐faceted and largely unexplored problem involving a variety of goals and possible approaches.

This paper describes one possible aspect of the interface, the design of a problem‐oriented computer language, that is, a language with commands and data format specifically geared to the field of water resources.
Mean range of linearly dependent normal variables with application to storage problems
Authors: Yevjevich Vujica
Published: February 2008

The exact equations for the mean range of some normal but autocorrelated variables, of known population means and known linear dependence, are developed. The basic hypothesis was that the exact expression in the general form for the mean range of linearly dependent normal variables is the same as for the normal independent variable, which form was derived from the mean range given by Anis and Lloyd. The data generation method (with a large sample of 250,000 random numbers) was used to assess the differences in mean ranges between the developed equations and the computer results. For three cases—the first‐and the second‐order Markov linear dependence and the simple moving average scheme—these differences are very small, and they are of the order of magnitude of the sampling errors for the data generation method. The expressions for exact values of mean range are derived for: (1) the general Markov linear dependence model; (2) the first‐order Markov linear dependence; (3) the general linear moving average scheme; and (4) the simple linear moving average scheme.
Determination of the hydraulic conductivity of unsaturated soils from an analysis of transient flow data
Authors: Vachaud Georges
Published: February 2008

From analysis of the water profiles obtained by gamma ray absorption during infiltration into soil columns, and of the wetting branch of the soil water‐suction water content relation, this paper suggests a method for checking the validity of the generalized Darcy's law and for computing the values of the hydraulic conductivity at various water contents. Tests have been made for horizontal infiltration and for capillary rise. In both tests, for a given water content, the capillary conductivity k is constant, and the generalized Darcy's law is valid and may be used to describe a transient flow in unsaturated soils.
Mathematical assessment of synthetic hydrology
Authors: Matalas N. C.
Published: February 2008

To generate multivariate synthetic sequences that will resemble multivariate historic sequences in terms of means, standard deviations, skewnesses, lag‐one serial correlation, and lag‐zero cross‐correlations, a multivariate, weakly stationary process is used. Techniques of regionalization and maximum likelihood estimates may be used to minimize the biases associated with the estimates of the parameters that characterize the historic sequences.
The dynamics of public roles in the selection of revenue sources in local water administration
Authors: Garrison Charles L. , Hill Duane W.
Published: February 2008

One of the largest voids in the information available to local decision‐makers on water use is the knowledge of limits placed upon the policy‐makers' opinions by their respective publics. Results from an effort to classify orientations toward debt‐retirement policy alternatives of a special rural‐domestic water district's public demonstrated: (1) that persons who would grant flexibility in policy‐making were lower social status newcomers with a low rate of political participation but a relatively high political efficacy, an urban outlook, high personal rigidity, and high deference toward authority; (2) that the restrictiveness of the resister who comes primarily from the high income, participant‐oriented, upper middle class is probably a function of his ideological framework and a consistent level of activity that gives him high potential for limiting the policy‐makers' decision‐making options; and (3) that the complaint medium is a viable component for measuring and classifying political behavior.
The relation between mainstream length and area in drainage basins
Authors: Smart J. S. , Surkan A. J.
Published: February 2008

Hack and Gray have both found that data on mainstream lengths and basin areas can be represented by the equation L′ = CAn′, where C is about 1.4 (measurements in miles), and n′ is about 0.6. Hack has suggested that the deviation of n′ from ½ can be explained by an elongation of drainage basin shapes with increasing area. We point out that variations of stream sinuosity with area can also affect the value of n′. A simple approximate formula is deduced that relates mainstream length, sinuosity, basin shape, and area, and shows how the contributions of sinuosity and shape variation to the quantity (n′ − ½) may be separated and evaluated. Data that illustrate these points are presented for both real and simulated stream systems. Our conclusions are: (1) Variation in mainstream sinuosity with area can be responsible for a significant part of the deviation of n′ from ½. (2) The generally accepted statement that drainage basins become more elongated as their area increases needs further investigation.
Note on ‘ New approach for estimating transmissibility from specific capacity’ by R. Theodore Hurr
Authors: Narasimhan T. N.
Published: February 2008

I was interested in the paper by Hurr [1966] on the estimation of transmissibility from specific capacity, since I too have concerned myself in the recent past with the same problem and allied aspects, but from a different angle.

I prepared [Narasimhan, 1966] on double logarithmic graph sheets (see Fig. 1) the variation of yield per foot of drawdown in relation to T and r2S/t. With the help of this chart, T can easily be extrapolated if the values of Q/s, r and t are known and a reasonably accurate idea of S is available from geological considerations. The estimated value of T in this method, as well as in the Hurr method, is only as accurate as that of the assumed value of S.
The synthesis of distributed inputs for hydrograph predictions
Authors: Brakensiek D. L. , Onstad C. A.
Published: February 2008

A surface flow model based on kinematic wave theory is applied to a flow system derived from the geomorphic properties of the watershed in question. This model facilitates the inclusion of conventional hydraulic methods for computations and avoids one of the major sources of error in watershed modeling: the lumping of input (rainfall excess). Input can be introduced as a distributed variable. The hydrograph synthesis process is evaluated by an objective function based on observed hydrograph peak flow. An example is used to illustrate the modeling process and its application.
Runoff estimation for very small drainage areas
Authors: Viessman Warren
Published: February 2008

Analyses of hydrologic data from high‐intensity short‐duration storms on very small drainage areas having varying physical characteristics indicated that a 1‐minute unit hydrograph could be used as the basis for generting runoff from an effective rainstorm input. The single parameter of the unit hydrograph (time constant K) was shown to be related to the physical characteristics of the drainage area. No evidence of the correlation between K and the storm pattern was discovered. Procedures are given for estimating net storm inputs.
Discussion of ‘The growth and development of attached stream bacteria: Part 1. Theoretical growth kinetics of attached stream bacteria,’ by W. M. Sanders III
Authors: Pincince Albert B.
Published: February 2008

Sanders [1967] has analyzed the growth kinetics of attached bacteria for a completely mixed model. Figure 1 is an idealized sketch of such a model.

The equation for the change in nutrient can be obtained by a mass balance as ∂C/∂t = qC0 ‐ qC + RV where

V = the volume of substrate in reactor, volume;

C = nutrient concentration in reactor and, therefore, in effluent, weight per unit volume;

C0 = influent nutrient concentration, weight per unit volume;

q = flow of substrate, volume per unit time;

t = time;

R = rate of addition of nutrients by bacterial action, weight per unit volume per unit time.
Optimal ground‐water mining
Authors: Domenico P. A. , Anderson D. V. , Case C. M.
Published: February 2008

A mathematical expression relating the economic worth of ground‐water mining to the remaining worth of a basin after it has been partially depleted permits establishment of an optimal, one‐time storage reserve that may justifiably be exploited. With water‐level position selected as the denominator common to both the ground‐water basin and its economic worth, the extreme conditions of perennial use of natural replenishment and depletion of the entire reserve emerge as special cases of the general model. This is reflected through an expression for optimal mining yield, a one‐time volume of nonrenewable water that may take on values ranging from zero to the maximum amount of usable water in storage. The maximizing conditions are expressed in terms of verbal decision rules and give new interpretation to the concept of overdevelopment generally associated with exceeding safe yield. A criterion is thus provided by which the economic state of development can be tested at any time.
Factor Analysis in Hydrology—An Agnostic View
Authors: Wallis James R.
Published: February 2008

It is suggested that factor analysis, if used in the classical manner, will never be of great value for hydrologic analysis. However, factor analysis used as a numerical procedure for screening variables and building effective regression equations is a useful and powerful tool for hydrologie analysis that can be expected to yield equations that outperform others when used as predictors for control samples.
Onset of Thermohaline Convection in a Porous Medium
Authors: Nield D. A.
Published: February 2008

The problem of the onset of convection, induced by buoyancy effects resulting from vertical thermal and solute concentration gradients, in a horizontal layer of a saturated porous medium, is treated by linear perturbation analysis. It is shown that oscillatory instability may be possible when a strongly stabilizing solute gradient is opposed by a destabilizing thermal gradient, but attention is concentrated on monotonic instability. The eigenvalue equation, which involves a thermal Rayleigh number R and an analogous solute Rayleigh number S, is obtained, by a Fourier series method, for a general set of boundary conditions. Numerical solutions are found for some special limiting cases, extending existing results for the thermal problem. When the thermal and solute boundary conditions are formally identical, the net destabilizing effect is expressed by the sum of R and S.
Analytical and Computer Solutions of Transient Water Tables for Drainage of Sloping Land
Authors: Chauhan H. S. , Schwab G. O. , Hamdy M. Y.
Published: February 2008

Transient water table drawdown in sloping land lying between parallel open ditches was obtained by solving Boussinesq's equation on the analog computer and by analytical methods for zero and time‐variable end conditions at the ditches. Comparison of the results with observations made on a viscous flow model indicated that the solution with time‐variable end conditions described the flow region beter than the solution with zero end conditions.