bluuebunny/crossref_metadata_2025 huggingface dataset:
Electric car disturbances at the magnetic observatory of the United States Naval Observatory
Authors: Davis C. H.
Published: February 2008

The magnetic instruments at the Naval Observatory in the city of Washington consist of a Kew vertical‐force needle, Kew declination needle, Kew horizontal‐force needle, and Mascart vertical‐force needle. These instruments are mounted underground, in a vault specially designed for the purpose, and are self‐registering by means of photography.

The Observatory itself is situated on Georgetown Heights in the suburbs of the city of Washington, on a spot selected by a commission appointed for the purpose. The purchase of this site, which is irregular in shape, and contains nearly seventy acres, was made in 1882. One of the principal requirements of the commission was to choose a site which should probably remain free from disturbances due to the proximity of a city and the effects of traffic. The electric railway had not then been perfected, and no more desirable site could have been selected. The construction of the new buildings, laying out and grading the grounds, and preparing for the removal of the instruments extended over a period of ten years, and the old site of the Observatory on the bank of the Potomac was finally abandoned in 1893.
The altitude of the aurora above the Earth's surface
Authors: Abbe Cleveland
Published: February 2008

During the past three centuries, numerous observers and physicists, astronomers and mathematicians, have endeavored to contribute to our knowledge of the altitude of the region whence the auroral light proceeds, and still the greatest diversity of opinion seems to prevail on this subject. Some observers—such as Captain Parry, Sir James Clark Ross, and Sir John Ross his uncle, Dr. Walker, and Professor J. P. Lesley—have seen the light in such positions between themselves and neighboring objects as to demonstrate that the aurora, like the lightning, descends to the very surface of the earth, and may even be entirely confined to the lowest stratum.

Others—such as Dr. Richardson, Sir John Franklin, Silbermann—have seen it so located among the clouds that its origin must be placed at or below their level, and therefore within a few thousand feet of the earth's surface. On the other hand, those who have calculated the altitudes of specific beams and arches by trigonometrical or equivalent methods, have generally found figures indicating altitudes between twenty and a hundred miles. Perhaps the highest altitudes that have been deduced were the following: Dalton, 150 miles; Loomis, 400 to 600; Bergman, 468; Boscovich, 825; Fournerius, 1,006; Twining, 1,100; Krämer, 1,945 kilometers, or 1,200 miles.
Note in regard to magnetic disturbances on St. George Island, Bering Sea
Authors: Putnam G. R.
Published: February 2008

The Pribilof Islands, in Bering Sea, are entirely volcanic in origin. St. George, the second in size of this group, is somewhat over twelve miles in length and five miles in width. Its surface is strewn with lava rock and scoria, except around the borders of the island, where there is a heavy growth of grass. There are, however, no well‐marked volcanic craters as on the sister island of St. Paul.
Ueber eine Methode, die Richtung Electrischer Verticalströme in der Atmosphaere durch Luftelectrische Beobachtungen zu Bestimmen
Authors: Elster J. , Geitel H.
Published: February 2008

In neuerer Zeit ist von verschiedenen Seiten die Möglichkeit erwogen worden, ob ein Bruchteil der magnetischen Kraft der Erde auf die Wirkung electrischer Ströme zurückzuführen sei, die von der Oberfläche der Erde in die Atmosphäre und umgekehrt fliessen. Die Existenz solcher Ströme würde,—ein nach Genauigkeit und geographischer Vollständigkeit ausreichendes Material erdmagnetischer Beobachtungen vorausgesetzt—in einfacher Weise daraus erschlossen werden können, dass das Linien‐Integral der magnetischen Kraft an der Erdoberfläche längs geschlossener Curven einen von Null verschiedenen Wert haben müsste. Die auf Grund des vorhandenen Beobachtungsmateriales sowohl für die ganze Erde, wie auch die unter Verwertung der Ergebnisse der magnetischen Aufnahmen von eng begränzten Gebieten für diese allein angestellten Berechnungen sind der Annahme solcher electrischer Verticalstrome im allgemeinen nicht ungünstig, doch machen die Berechner z. T. selbst darauf aufmerksam, wie unsicher bei dem geringen Betrage der gefundenen Stromintensitäten deren Existenz begründet ist.
Suggestions as to questions to be addressed to the directors of magnetic observatories
Authors: Eschenhagen
Published: February 2008

Es ist für die magnetische Forschung sehr nützlich, wenn ein vollständiges Verzeichnis aller magnetischen Observatorien nebst einer Uebersicht der an denselben ausgeführten Arbeiten und Veröffentlichungen allgemein bekannt würde.

Der unterzeichnete Vorsitzende des internationalen magnetischen Comités, welches von der Conferenz der Directoren meteorologischer Institute im September 1896 zu Paris ernannt wurde, ist bereit eine solche Zusammenstellung auszuführen und zur Veröffentlichung zu bringen.
On magnetic observations in the Azores
Authors: Albert
Published: February 2008

After having perceived the capital importance of the Azores, from their geographical position, for the establishment of meteorological observatories with a view to weather predictions, I thought that these observatories might be of service to other branches of science. For instance, the communications of Messrs. Neumayer, Mascart, von Bezold, and other eminent meteorologists, to the International Conference of Meteorologists in 1896, show that magnetic observations made at the Azores would offer the following advantages : (i) A situation near latitude 40°N. (page 22); (2) remoteness from the permanent causes of perturbation of actual magnetic observation, such as electric lighting tramways, and other applications of electricity; and (3) a geographical position intermediate between Europe and America, capable of furnishing most useful indications for the comparison of the magnetic curves obtained in these two parts of the world (pp. 36 and 90).

The examination of these considerations and different interviews which I had with M. Mascart, director of the Bureau Centrale Météorologique of France, convinced me of the advantage which would be gained if Captain Chaves, director of the Meteorological Observatory of Ponte Delgada, came to Europe to study the practical details of the magnetic service there. I therefore communicated my ideas to the Portuguese Government, who recalled Captain Chaves to undertake a mission in this sense.
Sur le mouvement diurne du pôle nord d'un barreau magnétiqué suspendu par le centre de gravité
Authors: Capello J. B.
Published: February 2008

En combinant les variations diurnes de l'inclinaison avec celles de la déclinaison, sur un plan perpendiculaire à la direction de l'inclinaison, résulte une courbe fermée.

Les variations ou écarts de l'inclinaison sont positives vers le sud, et celles de la déclinaison positives vers l'ouest.
On the relations between the variations in the earth currents, the electric currents from the atmosphere, and the magnetic perturbations
Authors: Lemström Selim
Published: February 2008

The paper contains an historical sketch of the observations and researches made on the earth currents by Lamont, Airy, Wild, Blavier, and others. The author describes the method employed by him for measuring the electro‐motive force of the electric currents coming from the atmosphere, and gives the evidence of the fact that the variations or earth currents occur a short time (five minutes) before the magnetic perturbations, and that the former are more numerous than the latter. From the observations in Sodankyla it is, however, proved that all magnetic perturbations are not preceded by variations in the earth currents, but that these probably are caused by electrical currents from the atmosphere to the earth, or vice versa.

The proofs of that conclusion are: (1) That the magnetic perturbations in polar regions have a contrary direction to those in more southern countries; (2) That at the times of auroras the electrical current from the atmosphere varies much, and must exert on magnetic instruments a marked influence depending on their position, relative to the space within which this current is moving. It follows from this that we can not find the causes of the magnetic variations, or, rather, perturbations, before we have investigated the earth currents and the electrical currents in the atmosphere.
Criteria for social investment
Authors: Arrow Kenneth J.
Published: February 2008

An elementary exposition of choice criteria for social investment is presented. The two causes for discounting the future benefits, time preference and opportunity cost, are discussed. The general reasons for special methods of measuring benefits are brought out. The subsequent discussion is a more detailed analysis of the application of these general principles, together with some remarks on the measurement of costs.
A note on a new method of cost allocation for combined power and water desalination plants
Authors: Barnea Joseph
Published: February 2008

The cost allocation method described here, which is for dual purposes or combined electricity water desalination plants, uses exclusively economic data. The method is based on the cost of power and water produced in single‐purpose plants and on the application of the cost relationship for a given net output of water and power to the total annual cost of a combined plant.
Field level planning of water resource systems
Authors: Hufschmidt Maynard F.
Published: February 2008

Comprehensive water resource planning formulates optimal programs, largely investment programs, in a systems context through use of principles of production and allocation economics and operations research. The planning problem entails maximization of an objective function, subject to constraints and to the production function. System design consists of derivation of three fundamental relationships—the cost‐input, benefit‐output, and output‐input functions—and their application to the system under study. The process of system design at field level consists of three major elements: preparation for planning; performance of basic physical, economic, and social studies; and formulating system designs, which in turn involves preliminary screening of development alternatives and detailed systems analysis of the alternatives that survive the screening. Major new techniques of analysis, typically computer oriented, include (1) optimal scheduling methods for the planning task, such as the Critical Path Method and its variants; (2) regional input‐output analysis to derive regional economic projections; (3) improved theoretical models and practical methods of data analysis for deriving benefit‐output functions, including those for flood prevention, outdoor recreation, and domestic and industrial water supply; (4) models for generating synthetic streamflow sequences and stochastic storage‐yield functions; (5) linear programming and rough simulation techniques for preliminary screening of development alternatives; and (6) detailed simulation analyses and response‐surface sampling for derivation and study of final system designs. Some of the new techniques can be used feasibly in current planning; others require further development and testing before they can be put to practical use.
The regimen of the Andrews Glacier in Rocky Mountain National Park, Colorado, 1957–1963
Authors: Outcalt Samuel I.
Published: February 2008

The Andrews Glacier is the only Front Range Glacier for which quantitative glacier net budget data are currently available. The National Park Service has run a transit‐stadia profile down the center of the glacier intermittently, late in the ablation season, since 1957. Ablation measurements were carried out during the summer of 1962. The Glacio‐Climatic Mapping Project prepared photogrammetric maps of the glacier surface from late September photography flown in 1962 and 1963. The variation of mean summer temperature and winter precipitation at two nearby weather stations can be related to mean‐height variation along the profile through regression analysis. The glacier, when viewed over the entire observation period, appears to be maintaining a near equilibrium condition. The study indicates the feasibility of applying the techniques of regression analysis to longer data series in the future.
Discussion of ‘Estimates of extreme values by different distribution functions’ by K. C. Majumdar and R. P. Sawhney [Comment]
Authors: Weiss L. L.
Published: February 2008

Majumdar and Sawhney [1965] present very useful comparisons of some distribution functions widely used in hydrological practice. The comparison made by expressing the ratio of the exceedance probabilities is most practical. Because the extreme‐value and the log‐normal distributions have perhaps the largest number of devotees, the ratios of equation 12 presented in Figure 1 are of prime interest.

Following equation 12 the authors state that the ratio depends ‘only’ on the coefficient of variation. This relationship holds true, of course, only if KT is calculated from equation 10 or 11, which implicitly assume that the period of record (n) is infinite. When that is not the case, the ratio is dependent on n as well as Cv
Computing lake evaporation in Illinois
Authors: Roberts W. J. , Stall John B.
Published: February 2008

A detailed study of lake evaporation in Illinois has been made utilizing a technique developed by the United States Weather Bureau. Monthly lake evaporation and pan evaporation have been computed for a 52‐year period utilizing parameters of air temperature, dewpoint, solar radiation, and wind movement. Records of seven weather stations in and around Illinois were used. The results were checked against observed pan evaporation data for various periods of years available at seven locations. The resulting map of annual lake evaporation in Illinois is based on considerably more information than was previously available and permits more efficient design and operation of water supply impoundments. (Key words: Computers, digital; evaporation; lakes; reservoirs; water management.)
Viscous model study of groundwater flow in a wedge‐shaped aquifer
Authors: Williams Dennis E.
Published: February 2008

Groundwater flow in sands of nonuniform thickness is 2‐dimensional in nature, assuming, of course, that the flow has no significant component of velocity in the y‐direction, so that its pattern in all vertical (x‐z) planes is the same. Rigorous expressions for the hydraulic head distribution in several such flow systems are available but, in general, they are relatively complicated and formidable to use. Analytical studies have revealed, however, that these expressions can be simplified considerably if the actual 2‐dimensional flow in such systems is replaced with unidirectional flow, that is, flow in which the vertical component of velocity can be assumed to be negligible. Theoretical analyses have shown that such an assumption can be safely made if the slopes of the confining beds in such systems are less than 20%. These analyses assume, of course, that the aquifer is homogeneous and that the hydraulic properties of the formation remain uniform in space and time. The approximate solutions thus obtained yield results that are in close agreement with those obtained from their rigorously derived counterpart. Such conclusions are here tested experimentally, using a viscous‐flow model in which 2‐dimensional flow is simulated. In general, the experimental results confirm the theoretical conclusions. (Key words: Groundwater; drainage; model study)
Effects of climatologic and basin characteristics on annual runoff
Authors: Mustonen Seppo E.
Published: February 2008

Climatologic and basin characteristics affecting the annual runoff in Finland are selected by the orthogonal regression method. Climatologic variables, especially seasonal precipitation and mean annual temperature, are found to be much more important than basin characteristics such as soil type and vegetation. Frost depth is inversely related to annual runoff. The percentages of cultivated land and peat land are not significant variables in these data. The simple linear multiple regression approach was successful (R = 0.943, s0 = 34 mm) in developing a reliable prediction equation. However, no statistical procedure can uncover the underlying laws governing runoff until the basic physical relationships are better understood. Furthermore, most available climatologic and basin characteristics are only indices of the combined effects of several physical factors. Hence, the utility of some of the more complex statistical approaches is questioned.
Experience with the pressure pillow as a snow measuring device
Authors: Penton V. E. , Robertson A. C.
Published: February 2008

Experience indicates that although pressure pillows provide useful accuracy for seasonal measurements of snow‐water equivalent, there may be problems in providing accurate measurements of the variation in melt rates for short periods of time. Temperature and barometric variations affect the accuracy of measurements of melt rates but are predictable or small. However, unexplained diurnal variations were found to be significant during the snowmelt period. These diurnal fluctuations are large enough to cause significant error in measurements of the daily melt but not in the measurements of the seasonal accumulation. (Key words: Snow; instruments)
High alcohols as antitranspirants
Authors: Gale J. , Roberts Edwin B. , Hagan Robert M.
Published: February 2008

The use of monomolecular films of high alcohols to reduce evaporation from open water surfaces has stimulated much work on the possibility of applying these materials to plants to reduce transpiration. The results of 17 such investigations indicate that at concentrations that reduce transpiration, these materials also reduce plant growth. The one study that reported reduction of plant transpiration and increase of growth was repeated, but with negative results. Analysis of the relative resistances of hexadecanol films to flow of CO2 and water vapor and their relation to resistances to flow normally found in plant leaves indicates that these films should reduce photosynthesis more than transpiration. It is concluded that such materials are not suitable as antitranspirants. (Key words: Evapotranspiration; plants; vegetation)
Variance spectrum analysis
Authors: Julian Paul R.
Published: February 2008

This paper is an annotated review of variance spectrum analysis. Faced with the impossible task of reviewing here the technique, providing illustrative examples from the field of hydrology, and providing learned insight into the uses of these techniques that are likely to be productive, I make no apology for the material included and omitted. The researcher with the appropriate problem and the ability to perceive that this or that particular tool is suited to the solution of that problem is the researcher who advances the science. It is my hope that the discussion and examples contained in this review will stimulate workers to acquaint themselves with spectral techniques and thereby prepare themselves to choose those problems in time (or space) series for which the techniques are suited. Spectrum and cross‐spectrum analyses are useful in analyzing the random or stochastic components in a time (or space) series. For certain problems auto‐ or cross‐correlation analysis may be most attractive, and for others spectrum analysis might be more appropriate.
A review of rainfall‐runoff, physical models as developed by dimensional analysis and other methods
Authors: Chery D. L.
Published: February 2008

Limited similitude relations for the construction of physical models of the watershed hydrologic system have been developed, using dimensional analysis, by Mamisao and Chery. Tests on both constructed models indicate that the hoped for similarity did not materialize, and that further testing is necessary to develop empirically the needed similarity relations. Grace and Eagleson have, using differential equations, also developed similitude relations for hydrologic system modeling and discussed the limitations of such modeling. Other individuals are also contemplating modeling, but their endeavors are not concerned with similitude relations, because their devices are non‐scaled representatives of parts of the natural hydrologic system.
Snow catch by Contier Crowns
Authors: Satterlund Donald R. , Haupt Harold F.
Published: February 2008

Study of interception storage of snow by two species of sapling conifers in northern Idaho revealed that cumulative snow catch follows the classical law of autocatakinetic growth, or

where Is, is interception storage, S is the interception storage capacity of the tree, e is the base of the natural logarithm, k is a constant expressing the rate of interception storage, P is accumulated snowfall, and P0 is accumulated snowfall at the time of most rapid storage (i.e., the point of inflection of the sigmoid curve). Interception storage conformed to the law in five storms in which snowfall began while the trees were bare, and in two storms in which snow fell while snow from previous storms persisted on the trees. Several small storms yielded insufficient data to define the appropriate constants, but inspection indicated no serious deviation from the general law.
Analysis of nonlinearities in ground water hydrology: A hybrid computer approach
Authors: Vemuri Venkateswararao , Dracup John A.
Published: February 2008

A hybrid computer method to solve nonlinear partial differential equations describing the flow of fluids in underground formations is described. Using finite difference methods, the problems are first programmed by a flow chart for a pure digital computer solution. Because the ability of resistance networks to solve a set of simultaneous equations instantaneously is recognized, major matrix inversion subroutines in the digital flow chart are replaced by analog resistance network hardware. Incorporation of analog hardware drastically reduces the computation time involved in inversion of large matrices. The resistance network constructed on an analog computer patch board allows an unparalleled flexibility not available in a digital computer.
Surface Chloride distribution in Maine lakes
Authors: Mairs Donald F.
Published: February 2008

Chloride analyses on surface water samples collected from 126 Maine lakes demonstrate the generally acknowledged trend toward decreasing chlorides as distance from the coast increases. Some anomalous values are reported, about half of which are in hardwater areas. The possibility is raised that highway salting in winter may affect surface chloride levels in Maine lakes.
Net rainfall under hardwoods and red pine in central Pennsylvania
Authors: Rogerson T. L. , Byrnes W. R.
Published: February 2008

Throughfall averaged 80% of gross summer precipitation both under a natural hardwood stand and under a red pine plantation in central Pennsylvania. Stemflow averaged 2% of gross precipitation in the hardwoods and 1% in the pine. Linear regressions relating net precipitation (Pn) to gross precipitation (Pg) were Pn = 0.907 Pg − 0.046 for the hardwoods, and Pn = 0.905 Pg − 0.045 for the pine.
A derivation of Dupuit solution of steady flow toward wells by matched asymptotic expansions
Authors: Dagan G.
Published: February 2008

An approximate solution of the steady and shallow free‐surface flow toward a well in a layer of infinite extent is obtained by expanding the velocity potential in a small parameter power series. This expansion is shown to be valid only in the vicinity of the well and is, therefore, called the inner expansion. An outer expansion, which solves the flow problem at large distance from the well, is derived by using the method of matched asymptotic expansions. The Dupuit approximation coincides with the zero order term of the potential outer expansion. The derivation of a second order outer term makes possible the discussion of the validity of the Dupuit approximation, which tends asymptotically toward the exact solution. In the outer zone, the streamlines are parabolic and are not orthogonal to the equipotentials. The method is illustrated by two numerical examples.
Physical and Economic Design Criteria for Induced Snow Accumulation Projects
Authors: Tabler Ronald D.
Published: February 2008

Snow fencing promises to be an important means of increasing surface water yield or ground water recharge on windswept watersheds where snow is an important form of precipitation. Assuming an equally spaced series of snow fences, a physical production function can be developed that relates fence spacing to the ‘most probable’ annual snow catch, based on a probability analysis of winter precipitation. The optimum scale of development in terms of fence spacing, determined by standard marginal analysis, indicates that the smaller the marginal value of output with respect to inputs, the greater the probability must be of the fences filling annually if net benefits are to be maximized.
Nonsteady Compressible Flow through Anisotropie Porous Mediums with Particular Reference to Snow
Authors: Fan S. S. T. , Yen Yin‐Chao
Published: February 2008

The equations describing the unsteady flow of air through an anisotropic layer of snow are solved numerically. It has been found that even at a moderate boundary pressure of 2 atmospheres, the penetration of the pressure front becomes appreciably more damped, and the rate of propagation reduces in the case of van der Waal's gas as compared with the case of ideal gas. These differences are more pronounced for pressures of 5 and 50 atmospheres. The results point out the need of caution in making the assumption of ideal gas behavior for dealing with problems of compressible fluid flow through porous mediums. Furthermore, for a medium of variable porosity, the use of a mean dimensionless porosity
instead of Φ = Φ (ξ) (ξ is the dimensionless depth of the medium) introduces an unrealistically large damping effect on the pressure distribution in the medium.
Snowmelt at an Index Plot
Authors: Pysklywec D. W. , Davar K. S. , Bray D. I.
Published: February 2008

A small experimental index plot has been installed in the open at a climatological station in the North Nashwaaksis Stream Basin, N. B., to obtain a reliable regional relation between snowmelt measured at the plot and meteorological parameters thermodynamically related to the snowmelt process.

The data collected during the 1966 spring snowmelt season were analyzed by three methods: The degree‐day method, the U.S. Corps of Engineers generalized snowmelt equations, and optimal regression equations derived from the measured snowmelt at the index plot and related thermal budget indices formed from individual meteorological parameters or a rational form of their product combinations. All three methods gave generally comparable results; their specific merits and limitations are discussed in the text. The per cent deviation of seasonal totals by the three methods varied from −15.6 to +54.5%. A comparison of the relative accuracy of the three techniques as daily predictors was obtained by taking the root‐mean‐squared values of the deviations of daily estimated snowmelt from the daily measured values; these ranged from 0.17 to 0.22 in.

It is suggested that experimental index snowmelt plots and computerized optimal regression equations offer possibilities for dependable predictions of point snowmelt rates that may be used as input information for estimation of basin‐wide snowmelt and hydrograph synthesis.
Discussion of “Similitude Theory Applied to Correlation of Flume Sediment Transport Data” by D. I. H. Barr and J. G. Herbertson
Authors: Maddock Thomas
Published: February 2008

Barr and Herbertson, in the abstract of their paper ‘Similitude Theory Applied to the Correlation of Flume Sediment Transport Data,’ state:

A rigorous method of correlation compatible with feasible laboratory procedures is presented and illustrated in figure form using available data. It was found that the bulk of the published data was in a form unsuitable for use in a rational correlation. The authors conclude that new experimentation is required and that could best be done by cooperation among institutions with the necessary apparatus.

The authors appear to say that their proposed approach to the analysis of sediment transport data is not supported by existing data; hence it is necessary to perform additional experiments in hopes of finding some data that will fit the plot.
Observations on Dredging and Dissolved Oxygen in a Tidal Waterway
Authors: Brown Charles L. , Robert Clark
Published: February 2008

Evidence indicates that resuspension of oxidizable bottom sediments in a tidal waterway caused significant reductions in the dissolved oxygen (D.O.) concentration of the water. During dredging, D.O. was reduced between 16–83% below normal.
Evaporative cooling of heated irrigation water by sprinkler application
Authors: Cline J. F. , Wolf M. A. , Hungate F. P.
Published: February 2008

Heated water was cooled rapidly to impact temperatures that produce optimum growth in plants by applying the water with a standard irrigation sprinkler. Maximum cooling was observed nearest the sprinkler, where the smallest droplets were measured, and temperatures and mean diameters generally increased with distance from the source. Impact temperatures of the water droplets approached but did not reach wet bulb temperatures. Water as hot as 50°C was cooled to droplet temperatures of 25°C or less when the sprinklers were operated in an associated arid climate and at line pressures greater than 25 psi. A theoretical treatment correlated well with one selected set of experimental data and with predicted cooling rates for specified droplets in several typical atmospheric conditions and one untypical condition for an arid climate. Only under the condition of high relative humidity at a given ambient temperature does it appear that cooling might be insufficient to produce usable sprinkler water from 50°C supply water for crop production.
Conditional probabilities of failures in reservoir operation for the Moran‐Gould Model
Authors: Venetis C.
Published: February 2008

The distribution of the number of failures n in N years of reservoir operation is examined via the Moran‐Gould model of seasonal inflows. This distribution is conditional on the initial state of the system. It is derived from the m‐step transition matrices (m = 1, 2, … N) and the vector of probabilities of intrayear failure corresponding to all states of the system Ei (i = 0, 1, 2,… k). Introduction of probability generating functions simplifies the presentation of the material. These functions are briefly discussed. A simple numerical example illustrates the theory.
The Vertical Movement of Water in Stratified Porous Material: 2. Transient Stages of Drainage to a Water Table
Authors: Bybordi M.
Published: February 2008

An equation is derived to describe the yield of water at a given time from a freely draining composite column of initially saturated porous materials in a gravitational field by using Green and Ampt's [1911] concept. The equation is supported by experimental results.
Movement of DDT and nitrates during ground‐water recharge
Authors: Scalf Marion R. , Dunlap William J. , McMillion Leslie G. , Keeley Jack W.
Published: February 2008

The Robert S. Kerr Water Research Center, U.S. Department of the Interior, and Southwestern Great Plains Research Center, U.S. Department of Agriculture, recently cooperated in a field investigation of the fate of DDT and nitrates when artificially recharged into the Ogallala aquifer. The USDA provided recharge and observation wells and hydraulic equipment for injecting 350 gallons per minute of water with known concentrations of radio‐active tracer, DDT, and nitrates. Following 10 days of recharge, the recharge well was pumped for 12 days at 500 gallons per minute. During recharge the nitrates moved to the observation wells e:ssentially at the same rate as the recharge water, and the DDT was adsorbed to the aquifer material very near the recharge well. During the pumping phase, 94% of both the recharge water and the nitrates was recovered. The concentration of DDT in the pumped water was about 16 times the recharge concentration at initiation of pumping but dropped below recharge concentration within one hour. Apparently a major portion of the DDT introduced during recharge was not recovered during pumping but remained in the aquifier.
Diel and Seasonal Variations in Physiochemical Limnology, Speed River, Ontario
Authors: Kelso John R. M. , MacCrimmon Hugh R.
Published: February 2008

Diel pulses occurred in pH, dissolved oxygen, and free carbon dioxide. Iron and fluoride levels were stable. Total alkalinity, silica, and turbidity levels varied, but not significantly. Wide diel ranges existed in ammonia, chloride, nitrate, nitrite, orthophosphate, sulphate, and specific conductance levels. High hexavalent chromium levels (0.57 mg/1) occurred only on one occasion. Diel means of these characteristics showed seasonal change fitting the seasonal trends evident during the year of observation. The nature and extent of diel variation are generally required to determine an effective procedure for examination of local changes in limnologic conditions.
A Ten‐Unit Water Level Sensing and Recording System
Authors: Ragan Robert M. , Hais Alan B.
Published: February 2008

An instrument to record a number of water levels on one chart for field studies was developed around a float‐pulley mechanism attached to the shaft of a potentiometer. A timing circuit allows one 6‐second recording cycle each minute for each of 10 sensors. Drift due to battery drain has not been encountered, and field performance has been satisfactory at a total cost of less than $400.
Weekly and monthly flows in synthetic hydrology
Authors: Moreau David H. , Pyatt Edwin E.
Published: February 2008

A nonstationary model for synthesizing weekly flow patterns, such that means, variances, and covariances of weekly and monthly flows, as estimated from historical records, will be preserved under the assumption of a Markov structure for monthly flows, is developed and applied to the Haw River in North Carolina. Analyses show excellent agreement between statistics of the historical record and those of the simulated record when weekly flows were assumed to follow a log normal distribution. A moving average process is used to reduce sampling errors of parameter estimates from the historical record.
Theory of multiple leaky aquifers
Authors: Herrera Ismael
Published: February 2008

This paper is an extension of previous work by Herrera and Figueroa to multiple leaky aquifers. The equations governing the motion of such systems are transformed to obtain a simpler system suitable for numerical treatment. An essential feature of the method is the introduction of a lag time that occurs because the influence of any aquifer is not transmitted instantly to its neighbors. This approximation is suitable for treating cases for which the conditions on the aquifers vary slowly. The numerical treatment of the resulting system of equations is of the same order of complexity as that for a single aquifer.
Stream Temperature Prediction Model
Authors: Morse William L.
Published: February 2008

Given certain meteorologic and hydraulic‐hydrologic data a dynamic deterministic one‐dimensional model, based on evaluation of the heat exchange across the air‐water interface, predicts the water temperatures of streams. The model itself is a quasilinear partial differential equation that represents an abbreviated energy conservation equation. For an extended upper reach (200 miles) of the Columbia River during July 1966, it has predicted water temperatures on the average within 0.3°F. More important, this model has been subjected to a statistical validity test which indicates a certain level of acceptance.
Dependence of stream link lengths and drainage areas on stream order
Authors: Ghosh A. K. , Scheidegger A. E.
Published: February 2008

It has been suggested in the literature that the lengths of interior links (distances along river course between subsequent junctions) in a given river network are independent random variables drawn from the same population. However, the validity of this basic hypothesis with relation to nature had never been investigated. Thus a test was made to find the exact relationship between the stream lengths and the corresponding stream orders by comparing the theoretical length ratios calculated, assuming all link lengths to be equal, and the natural length ratios for rivers with the same number of first order streams. The results show that the link length always has a tendency to increase geometrically with the Strahler order. This leads to the conclusion that a law of link lengths exists that is similar to the well‐known laws of stream orders, stream lengths, and areas. A similar analysis with regard to the areas drained by each link in a river network shows that these areas are constant.
A Steady State Optimal Design of Artificial Induced Aeration in Polluted Streams by the Use of Pontryagin's Minimum Principle
Authors: Davidson Burton , Bradshaw Robert W.
Published: February 2008

Optimal control theory based on Pontryagin's minimum principle has been applied to the problem of specifying the steady state distribution of artificial aeration in polluted rivers. The optimization was developed for a general integral type cost functional with weighted energy constraints. The system equations used were of the classical Streeter‐Phelps genre with an induced aeration term added as the control function. The formulation of the problem yielded the famous Riccati‐Kalman structure and an analytical solution. Several optimal and suboptimal aeration designs at different temperature levels were obtained using a digital computer and an automatic plotting routine. An analog computer was used in the critical stages of the numerical solutions. Results from the analog computer pointed the way to the ultimate use of Laplace transform techniques in conjunction with a digital computer for maximum accuracy.
Variation of the Longitudinal Dispersion Coefficient in the Delaware River Estuary as a Function of Freshwater Inflow
Authors: Paulson Richard W.
Published: February 2008

Three solutions of the one‐dimensional steady state diffusion equation for a conservative substance (ocean salinity) have been derived for an estuary whose cross‐sectional area increases linearly in the seaward direction. One solution results from the assumption that freshwater enters the estuary only at the upstream end. The two other solutions result from the assumption that freshwater inflow increases as a function of distance along the estuary. The latter two solutions are separated by different upstream boundary conditions. The three solutions have been tested with U.S. Geological Survey water quality monitor data from a reach of the Delaware estuary. The tests indicate that the longitudinal dispersion coefficient, which is assumed to be spatially constant at any particular time, increases with freshwater inflow from about 140 to 200 m2/sec as the freshwater inflow at Trenton, New Jersey, increases from 2000 to 6000 cfs (60 to 180 m3/sec).
Velocity Measurement with Radioactive Spheres
Authors: Yen Ben Chie , McGillivray Terrence L.
Published: February 2008

Experimental evidence shows that the use of radioactive spheres as a flow velocity tracer is feasible. The technique involves trapping a small amount of radioisotope inside a sphere and then measuring the motion of the sphere in the flow. For steady uniform subcritical turbulent flows tested with the Reynolds number up to 13,000 and the flow depth to sphere diameter ratio greater than 1.7 the accuracy of flow velocity measurement with floating tracers is usually within ± 7%. The accuracy can be improved if the correction for the relative velocity between the fluid and the sphere is made. The advantages of this technique are its simplicity, its relatively small contamination problem, its low cost, and its potential to be used in a wide range of flow conditions.
Plant Cover, Runoff, and Sediment Yield Relationships on Mancos Shale in Western Colorado
Authors: Branson F. A. , Owen J. B.
Published: February 2008

Relationships between vegetation and hydrologic measurements for 17 watersheds near Grand Junction, Colorado, were subjected to correlation analyses. Six years of vegetation measurements, four vegetation measurement methods, and 15 years of hydrologic records were used in the analyses. Highly significant correlation coefficients were found for percent bare soil and runoff, but the relationships between bare soil and sediment yields were not statistically significant. Geomorphic parameters such as angle of junction, mean slope, drainage density, relief ratio, length‐width ratio, and watershed area were more highly correlated with sediment yields than with runoff. Correlation coefficients for spring vegetation measurements and runoff were higher than for autumn measurements. First contact methods and step point vegetation measurement methods were superior to the loop method and the all contacts point method. Curves for the relationship of runoff to bare soil were strikingly different for three sets of watersheds from different precipitation zones. Bare soil measurements may provide rapid and inexpensive estimates of runoff for watersheds similar to the ones studied.
Transpiration of Ponderosa Pine and Douglas Fir after Treatment with Phenylmercuric Acetate
Authors: Brooks Kenneth N. , Thorud David B.
Published: February 2008

Phenylmercuric acetate (0.001 M) reduced transpiration of ponderosa pine and Douglas fir in a greenhouse without increasing foliage temperatures. The reductions were 48% and 24%, respectively, and the effect lasted at least seven days. Some foliage on one treated tree of each species showed browning four weeks after treatment.
The Measurement of Gradation Using Surveyed Cross Sections
Authors: Johnson F. A.
Published: February 2008

A variation of hypsometric analysis gives quantitative information on relative changes within a river cross section. Area‐elevation curves and area‐distance curves determine the degree of activity of segments of a cross section.
Measuring Flow through Crest Gates
Authors: Terney George E.
Published: February 2008

Equipment has been developed for the measurement of flow through crest gates on movable crest dams. Because of divergency of flow upstream of gate openings, conventional flow measuring devices are not applicable. This system suspends a strain gage and sensor in the flow and measures the resultant forces on the sensor.
Saline Water Symposium: Introduction
Authors: Johnson A. I.
Published: February 2008

‘Saline water—A valuable resource’ was the unusual concept that became the subject of a symposium presented on April 24, 1969, during the Fiftieth Annual Meeting of the American Geophysical Union in Washington, D.C. The symposium was sponsored by the Groundwater Committee, Section of Hydrology, American Geophysical Union.

The objective of this symposium was to provide a new perspective on the value of saline ground water and saline aquifers, based on the most recent industrial and technological developments. The rapid development of desalination technology has brought with it the recognition of a new intrinsic worth for saline water, especially saline ground water. In addition, increased awareness in surface pollution and the need for protection of man's environment has greatly intensified the interest in use of saline aquifers for disposal, or storage, of toxic industrial wastes and other fluids. With these trends in mind, the Groundwater Committee believed that a symposium on this subject was timely in developing among hydrologists and water resource managers the recognition that saline ground water and saline aquifers actually could be a valuable resource.
Regulatory Aspects of Liquid Waste Injection into Saline Aquifers
Authors: Warner Don L.
Published: February 2008

Industrial waste water injection wells have been constructed in at least 20 states. This distribution has caused many state and federal government officials to consider how best to regulate the construction and operation of these systems. Review of the procedures followed in various states has led to the conclusion that essential steps in the development, operation, and regulation of waste water injection systems are: (1) Preliminary assessment by the applicant of the geology and geohydrology at the proposed site and of the suitability of the waste water for subsurface injection, in consultation with the appropriate regulatory authorities. (2) Formal request, by the applicant for permission to drill and test a well or convert and test an existing well for underground waste water injection. (3) Construction or conversion and testing of the well, and submission of subsurface information to the regulatory authorities. (4) Formal request by the applicant for permission to use the completed well for waste water injection. (5) Operation of the system under supervision of the regulatory authorities. (6) Abandonment of the well by the operator with the approval and supervision of the regulatory authorities. In many states, the responsibility for regulation of injection wells, the necessary technical expertise, and the basic geologic information for decision making are located within several agencies. Although this situation complicates the regulation of subsurface disposal, it can have the desirable effect of involving a greater spectrum of technical competence and experience than would otherwise be available.
Storage of Natural Gas in Saline Aquifers
Authors: Katz Donald L. , Tek M. Rasin
Published: February 2008

Value, extent, and engineering description of underground storage of natural gas in saline aquifers are reviewed. Problems associated with evaluation of aquifer storage prospects, geologic and geochemical requirements have been discussed along with topics related to operating pressures, gas retention, and pump tests.
A Note on Linear Decision Rules
Authors: Nayak Satish C. , Arora Sant R.
Published: February 2008

In a recent letter Loucks [1970] made a few interesting comments about the linear decision rule proposed by Revelle et al. [1969].

Loucks' first comment concerns the initial storage volume defined as a0 · C; a0 ≥ am, where a0 and am are specified fractions. The release constraints for the first time period are given by

urn:x-wiley:00431397:media:wrcr864:wrcr864-math-0001
where a1, b1, f1, a0, am, and C have the same meanings as defined by Loucks and Revelle et al.
Generating Skilled Manpower for Irrigation Projects in Developing Countries: A Study of Northwest Mexico
Authors: Haissman I.
Published: February 2008

A simple, practical method for finding the numbers of skilled personnel necessary for the successful implementation of irrigation projects in developing countries, and for designing a training system to generate this personnel is given. The occupations critical to irrigation development and the agricultural activities in which each occupation is deployed are listed. A series of coefficients, based mainly on the successful irrigation development in northwest Mexico, determines the manpower quantities required as functions of given project parameters. A network flows model and a linear programing model are developed for designing the appropriate training systems.
Law of Stream Relief in Horton's Stream Morphological System
Authors: Fok Yu‐Si
Published: February 2008

Within a river basin, the streams can be classified by the Horton‐Strahler stream order system. In 1945, Horton introduced the law of stream lengths and the law of stream slopes and found the average stream lengths and slopes as semilogarithmic functions of the stream order. In this study, paralleling Horton's development, the law of stream relief is proposed and the average stream relief is found also to be a semilog function of the stream order. Results from numerical analysis indicate that the riverbed profile can be described by a semilog equation expressing stream relief as a function of stream length. The F value in the stream relief equation may be considered as an indicator of the riverbed profile properties; however, more investigations are needed before any conclusive statements can be made.