bluuebunny/crossref_metadata_2025 huggingface dataset:
Allgemeiner Ausdruck für die Coefficienten der Formel für die Ablenkung einer Magnetnadel durch einen Ablenkungsstab in beliebiger Lage
Authors: Börgen C.
Published: February 2008

Der Ausdruck für die Ablenkung einer Magnetnadel durch einen Magnet ist bisher meistens nur für bestimmt definirte Stellungen des letzteren und bis zu einer massigen, aber im allgemeinen ausreichenden Grenze der negativen Potenzen der Entfernung zwischen Ablenkungsstab und Nadel abgeleitet worden. So von Gauss für die Lage des Ablenkungsstabes in der Horizontal‐Ebene durch die Nadel und senkrecht zum magnetischen Meridian, von Lamont für diese und verschiedene andere Lagen, besonders für die, seitdem vielfach zur Bestimmung der horizontalen Componente der erdmagnetischen Intensität angewandte Stellung des Ablenkungsmagnets senkrecht zur Nadel. Von den Beschränkungen der speciellen Lagen des Ablenkungsstabes in der Ebene machten sich frei Riecke, Kowalsky und Fritsche, aber auch sie behielten die Beschränkung bei, dass die Axe des Magnets in der durch die Nadel gelegten horizontalen Ebene liegen solle. Dr. Fritsche ging auch noch einen Schritt weiter und führte die Reihen‐Entwickelung bis zur Potenz e−9, während man sich bisher mit der Potenz e−7 begnügt hatte.
Sur l'inclinaison de l'aiguille aimantée à l'époque étrusqu
Authors: Carlheim‐Gyllensköld V.
Published: February 2008

Les premières observations directes de l'inclinaison de l'aiguille aimantée datent de la fin du XVIe siècle; des informations antérieures pouvaient être tirées de la position du point de convergence des rayons de l'aurore boréale, si cet élément avait été observé au moyen‐âge.

Dernièrement M. Folgheraiter a publié sur le même sujet plusieurs notes intéressantes, dont M. Chistoni a fait une analyse dans le numéro 2, tome II, de ce journal. En se reportant à l'aimantation conservée par certains objets d'argile cuite, l'Auteur est arrivé à ce résultat, que l'inclinaison en Italie à l'époque étrusque, au VIIIe et VIe siècles avant notre ère, a été nulle ou même négative.
Elster and Geitel's résumé of recent papers on atmospheric electricity
Authors: McAdie Alexander
Published: February 2008

In this supplement to the Year‐book of the Ducal Gymnasium at Wolfenbüttel for 1897, Professors Elster and Geitel sum up in twenty‐four closely printed pages the chief results of the more recent investigations in atmospheric electricity. Few are more competent to undertake such a task. While there has been considerable activity displayed in many parts of the world lately in connection with atmospheric electricity, probably nowhere has this activity been more marked than at Wolfenbüttel. We do not forget the work of Professor F. Exner, the occasional papers of Lord Kelvin and his co‐workers, and the contributions of Schuster, Chree, Andrée, and others.
Le nouveau pavillon magnétique de l'observatoire du Parc Saint‐Maur
Authors: Moureaux Th.
Published: February 2008

L'observatoire du Parc Saint‐Maur est une dépendance du Bureau central météorologique de France; il est situé au voisinage de la Marne, à 12 kilomètres E. SE. de l'observatoire de Paris, et à 7 kilomètres des limites de la capitale. Ses coordonnées géographiques sont:Longitude, 0° 9′ 23″ E. de Paris.Latitude, 48 48 34 N.

La propriété, en grande partie boisée, a une superficie de trios hectares; des rues la bordent sur ses quatre côtés.
On a simple method of obtaining the expression of the magnetic potential of the Earth in a series of spherical harmonics
Authors: Schuster Arthur
Published: February 2008

The methods which have been employed so far to represent the earth's magnetic potential in a series of spherical harmonics suffer from the serious defect that the different coefficients are not determined independently of each other. Thus, in the latest and most accurate computation of Adolf Schmidt, the value of the first and largest coefficient was found to be 1,872, 1,913, or 1,921, according as the expansion is supposed to end with terms of the third, fifth, or seventh order respectively. If the value of the potential were known at all points of the earth's surface, it is well known how, by a direct integration over the surface of the sphere, each coefficient may be separately determined. But there are large tracts of the earth over which the magnetic forces have not been directly observed, and hence some form of interpolation is always implied in whatever method is employed.
Efficiency criteria for market transfers of water
Authors: Hartman L. M. , Seastone D. A.
Published: February 2008

Adjustments of water between uses and areas of use is essential for the public interest in economic efficiency because of changing demands for water, differential rates of regional growth, and limited supplies. The physical aspects of water supplies give rise to rather complicated legal rules regarding property right management, particularly where transfers of ownership are attempted between uses and areas of use. Transfers entail effects on third party users, and the present legal restrictions on transfers do not lead to an economically efficient use of water. Application of marginal efficiency conditions to a water transfer and consideration of physical interrelatedness effects indicate that present procedures take into account protection of losers but do not allow for compensation from third party ‘gainers.’ Conclusions from an economic analysis of the transfer problem indicate that the benefits from the interrelated use before and after the transfer must be taken account of in specification of legal rules. Adoption of such rules would be necessary for efficient market allocation.
Recent results from a mathematical model of water pollution control in the Delaware Estuary
Authors: Thomann Robert V.
Published: February 2008

The basic concepts of systems analysis and optimum (least‐cost) water pollution control are presented. The equations utilized to describe the time and space variability of dissolved oxygen are presented in a systems analysis context, and their usefulness in this form is discussed. The application of the mathematical model to the control of dissolved oxygen in the Delaware Estuary is given. Recent computer solutions are illustrated, and the sensitivity of the least‐cost dissolved oxygen improvement solutions to the rate of atmospheric reaeration is presented.
Comparison of measured and calculated hydraulic conductivities of unsaturated soils
Authors: Jackson R. D. , Reginato R. J. , Van Bavel C. H. M.
Published: February 2008

Three methods to calculate the unsaturated conductivity of soil from its moisture characteristic were tested. Calculated values were compared with direct measurements of conductivity for both sorption and desorption for a sand. Also, comparisons were made for three soil materials. The method of calculation proposed by Millington and Quirk [1959], when matched at the saturated conductivity, gave good results.
Accuracy and precision of laboratory and field methods for the determination of detergents in water
Authors: Wayman C. H. , Miesch A. T.
Published: February 2008

The accuracy and precision of two field methods and a laboratory method for determining detergent (alkylbenzenesulfonate) in water have been investigated. Commercially available kits were used for the field methods. A total of 660 determinations were made by two analysts on prepared solutions containing both branched‐chain and straight‐chain detergents. One of the field methods contains large amounts of negative bias that vary with concentration level. The other field method has poorer precision than the laboratory method but no large amount of bias.
Factors that influence streamflow in the Northeast
Authors: Lull Howard W. , Sopper William E.
Published: February 2008

Average annual and seasonal runoff and daily mean discharges at selected flow durations of 137 watersheds in the northeast United States totaling less than 100 square miles were related to selected climatic, topographic, and land‐use variables. The most influential variables on annual and seasonal discharges, in descending order, were precipitation, percentage of watershed area in forest cover, elevation, latitude, July mean maximum temperature, and percentage of swamp. Isohyetal precipitation was more highly correlated with average annual runoff than precipitation values from stations closest to the watersheds. The degree of correlation of average annual runoff with average annual precipitation in nonmountainous physiographic units was related to the distance between the precipitation station and the center of the watershed. The proportion of forest cover was correlated positively with runoff, its influence very likely integrating a number of environmental factors that would tend to produce greater runoff.
Some criteria for the measurement of rainfall and runoff
Authors: Eagleson P. S. , Shack W. J.
Published: February 2008

Techniques of linear analysis are used to study urban and rural drainage basins as low‐pass filters. The frequency passband of the basin is determined in terms of its physical characteristics. This determination is used, in conjunction with the spectral representation of input rainfall, to investigate the necessary response characteristics of rainfall‐ and runoff‐measuring instruments. (Key words: Hydrologic systems; instruments; rainfall; streamflow)
Diurnal variations in the summer water vapor transport over North America
Authors: Rasmusson Eugene M.
Published: February 2008

Maps of the zonal and meridional components of the vertically integrated total horizontal mean flux of water vapor have been constructed for the North American Sector using 0000 GMT data from the period June through August 1958. Flux divergence maps, computed from the 3‐month average flux maps and from the average of the three individual monthly flux maps, are in good agreement. However, important diurnal flux variations exist over much of this area, at least during the summer months, so that data from only one observation time do not adequately define the mean daily flux and flux divergence. (Key words:North America; atmosphere; hydrologic cycle)
Relationship between precipitation, evaporation, and runoff in tropical‐equatorial regions
Authors: Solomon S.
Published: February 2008

Bouchet's theory on actual and potential evaporation can be used as a basis to develop semi‐empirical relationships between precipitation, actual evaporation, and radiation. These relationships are curvilinear, and the derived precipitation‐runoff relationships are also curvilinear. Since the variation of annual radiation from one year to another in tropical‐equatorial regions is not very significant, the average value of annual radiation can be approximated using direct measurements or indirect estimates from data taken over a period of from two to five years. This value can be used with the semi‐empirical relationship developed in the paper to obtain fair estimates of the annual variation of actual evaporation and runoff from data on annual precipitation and good estimates of the long‐term averages of these hydrologie characteristics. Bouchet's theory can be used to analyze evaporation and runoff for periods of less than one year and for estimating lake and reservoir evaporation. However, in this case, the assessment of the effect of heat and moisture storage requires further investigation.
Time series analysis
Authors: Matalas N. C.
Published: February 2008

A characteristic feature of hydrologic events is that they are not independently distributed in time. The degree of linear dependence between events k time units apart is measured by the serial correlation coefficient. This correlation, which tends to decrease with an increase in k, is attributed to storage processes in the atmosphere or within the drainage basin. The correlation measures the degree of redundancy of information yielded by each hydrologic event. This redundancy implies that statistical parameters computed from a sequence of events are less reliable than is indicated by the sequence length. Hydrologic sequences are formulated in terms of generating models to account for serial dependence between events, to allow prediction of events at future time points, and to assess the effect of serial dependence on hydrologic studies.
Synthetic hydrology based on regional statistical parameters
Authors: Benson M. A. , Matalas N. C.
Published: February 2008

The generation of a long series of hydrologic events by use of the statistical parameters based on a short sample has come to be known as synthetic hydrology. In present practice, there are two major deficiencies in the method. There are large errors due to the sampling errors of the original sample, and there is no way to generate a series for an ungaged location. The authors propose a method to correct for these deficiencies.
A method of determining the permeability and effective porosity of unconfined anisotropie aquifers
Authors: Dagan G.
Published: February 2008

The equations of unsteady flow toward a partially penetrating well in an unconfined aquifer of finite thickness are solved by linearization. It is assumed that the aquifer is nondeformable and that the effective porosity at the water table is constant. It is also assumed that the aquifer is anisotropic (the principal axes of the permeability tensor being horizontal and vertical, respectively), that the pumping discharge is constant, and that the drawdowns are small. The vertical component of the flow velocity is not neglected. The solution is, therefore, equally valid in the vicinity and at large distances from the pumping well. In the latter case, it coincides with the Theis solution. A method of matching the theoretical solution with drawdown measurements during pumping tests is outlined. By the matching method the horizontal and vertical hydraulic conductivities and the effective porosity of the aquifer may be determined. The method is illustrated by analyzing data from pumping tests carried out in three anisotropic aquifers.
Misconceptions in hydrology and their consequences
Authors: Yevjevich Vujica
Published: February 2008

Several misconceptions have been introduced into hydrology that have had adverse consequences on the science and on water‐resources development. Persistent use of the concept of maximum precipitation and maximum probable precipitation, for which there is no physical proof, has discouraged research into the structure and probability of extreme events, and may have led to an unwarranted sense of security concerning flood‐control works. Attempts at long range forecasts of water supply based entirely on meteorological processes have misdirected research and raised false expectations. A misconception that hydrologic processes are composed of a limited number of hidden periodicities has retarded the use of modern stochastic analyses of time series. Cloud‐seeding to increase numbers of raindrops rather than their coalescence may have had a negative effect on precipitation in arid regions. Considering ground water, instead of the aquifer, as a resource has stressed the technology of withdrawal at the expense of study of methods of recharge and has led to much unplanned overdraft of ground water. Use of descriptive instead of numerical variables has delayed the application of modern statistical methods to planning the exploration of the ground‐water environment. As a result of the neglect of the stochastic properties of porous mediums, fluid mechanics theory has not departed far from the original works of Darcy. Hydrology has developed slowly because it has been considered an appendage of hydraulic engineering rather than a natural science.
Dispersion at the interface of miscible liquids in a soil
Authors: Li Wen‐Hsiung , Yeh Gour‐Tsyh
Published: February 2008

When two miscible liquids flow through a porous medium (e.g., fresh water and salt water in an aquifer), the dispersion at the interface is described by Fick's law with a velocity‐dependent coefficient. In the first part of this paper, the horizontal flow of two liquids is used to demonstrate that the influence of gravity and the effects of the differences in density and viscosity are usually negligible. Then solutions are presented for the dispersion at the interface of liquids in two‐dimensional flow.
The investigation of water flow through porous mediums by means of radiotracers
Authors: Ellis W. R. , Kevi L. , Wiebenga W. A.
Published: February 2008

The radioisotope bromine 82 was used to measure the flow of water through a packed sand column. It was shown that the commonly accepted Dupuit‐Forchheimer assumption did not apply under thess conditions. Some information was also obtained on lateral dispersion using iron gauzes and copper 64 solution.
Nonsteady‐State Flow in Phreatic Aquifers
Authors: Weinberger Hershel
Published: February 2008

Analytic solutions of equations for ground‐water flow that contain inertial terms are derived and compared with solutions of equations assuming Darcian flow. The differences between the calculated seepages are immeasurably small for practical values of aquifer constants.
Atmospheric Contributions to Water Quality of Streams in the Hubbard Brook Experimental Forest, New Hampshire
Authors: Fisher D. W. , Gambell A. W. , Likens G. E. , Bormann F. H.
Published: February 2008

The balances of input in atmospheric precipitation and discharge in streams have been determined for selected mineral constituents in three small tributaries to Hubbard Brook in the White Mountains of New Hampshire. Inputs and discharge of sulfate, ammonium, and nitrate were calculated from hydrologic data, together with chemical analyses of weekly samples of precipitation and streamwater taken over a 2‐year period. The calculations show that precipitation provides most of the 30–50 kilograms of sulfate per hectare carried annually by the streams and that inputs exceed outflows of ammonium and of nitrate. Maximum effluent nitrate concentrations of 2 mg/l (milligrams per liter) are observed in early spring. Measurements of pH indicate that the hydrogen ion is one of the major cations in precipitation over the area. Determinations were made of the discharge of bicarbonate, silica, and aluminum in the streams. Annual stream loads of silica ranged from 20 to 40 kilograms per hectare. Effluent bicarbonate and silica concentrations vary directly with each other and inversely with aluminum.
A System for Measuring Conductivity, Acidity, and Rate of Water Flow in a Forest Soil
Authors: Cole Dale W.
Published: February 2008

An integrated system for collecting, recording, and analyzing data describing the behavior of water flowing through a forest soil has been developed. The collecting and recording components are located on a lower terrace of the City of Seattle Cedar River watershed in western Washington. This system includes tension lysimeters installed such that the overlying soil and rooting systems are undisturbed. The lysimeters are constructed from a fused aluminum oxide disk 11 inches (28 cm) in diameter. The suction to each lysimeter is maintained through a single controlled vacuum source. Solutions collected during periods of flow are passed through flow cells measuring conductivity, acidity, and rate of water flow. The sensitivity of the soil moisture flowmeter is in excess of 0.002 cm/hr. The electrical output from the flow cells is coupled to a data‐logging facility and printed as perforations in paper tape. Computer analysis converts these data to tabular and graphic form. Examples demonstrating the functioning of the system during periods of flow are presented.
Optimal Identification of Lumped Watershed Models
Authors: Labadie John W. , Dracup John A.
Published: February 2008

Though several investigators have noted the consistent nonlinearity of hydrologic system response to rainfall, nonlinear models have been avoided because of computational difficulties associated with the identification of model parameters from historic records. A few nonlinear models have been proposed, but the parameter identification methods lack generality and the capacity to deal with complex models. Through quasi‐linearization, implicit solutions to a large class of nonlinear models can be written in terms of a maximizing operation on linear equations. This algorithm also provides for systematic determination of the optimal values of model parameters in the identification problem. Furthermore, a complete set of accurate initial conditions need not be supplied. Application of quasi‐linearization to a recent nonlinear conceptual model of watershed response displayed in particular (1) The simplicity of the computer programing through the use of standard subroutines and (2) The rapid convergence characteristics of the algorithm.
Field Measurement and Use of Soil‐Water Properties
Authors: Davidson J. M. , Stone L. R. , Nielsen D. R. , Larue M. E.
Published: February 2008

The hydraulic conductivity versus soil‐water content relation for different soil depths was measured in the field for three soil profiles. The soils varied in physical properties from homogeneous to heterogeneous with depth and from loamy sand to silty clay in surface soil texture. Hydraulic conductivity values calculated from drainage data taken during different time intervals compared favorably with each other and showed no measurable hysteresis. The soil‐water flux at various soil depths with and without evaporation at the soil surface was measured. The rate at which water drained from each of the profiles was predicted using Darcy's equation and some simplifying assumptions. The agreement between theoretical and measured results is discussed in terms of soil heterogeneity with depth.
A Battery Powered Proportional Stream Water Sampler
Authors: Fredriksen R. L.
Published: February 2008

A stream water sampler was designed and tested to sample water from a stream at a rate proportional to the streamflow rate. A composite of samples taken in this manner is an estimate of the mean concentration of constituents carried by the stream while the sample was collected. The instrument is suitable for estimates of transport of suspended or dissolved constituents in small streams. The sampler can be built for under $1000.
Effects of kaolinite as a reflective antitranspirant on leaf temperature, transpiration, photosynthesis, and water‐use efficiency
Authors: Abou‐Khaled Antonie , Hagan Robert M. , Davenport David C.
Published: February 2008

Transpiration and photosynthesis are influenced by the optical properties of leaves. Application of a uniform white coating of kaolinite (about 225 mg dm−2) to the upper leaf surface produced significant changes in the spectral curves (reflectivity, transmissivity, and absorptivity) of Valencia orange leaves. Photosynthetic light response curves of leaves of orange, lemon, rubber plant (all hypostomatous), and bean (amphibiostomatous) were modified by the reflective material, which at low light intensities decreased photosynthetic rates and increased light saturation levels. The white coating cooled the leaves 3–4°C and reduced transpiration 22–28% under conditions of high light intensity, warm air, low relative humidity, and low wind velocity. However the rubber plant under the same conditions showed a smaller reduction in transpiration (less than 10%), indicating effective self‐regulation of its water loss. These experiments demonstrated that water‐use efficiency of leaves can be improved, particularly under high light intensities.
Increases in Water Yield Following Clear‐Cut Logging in the Pacific Northwest
Authors: Rothacher Jack
Published: February 2008

Increases in water yield following timber harvest roughly conform to the proportion of the area cleared. In high precipitation areas of the Oregon Cascades, clear‐cut logging can increase annual water yield 18 inches. Approximately 80% of the increase occurs during the October to March season.
Stochastic Models in Hydrology
Authors: Scheidegger Adrian E.
Published: February 2008

The stochastic models that can be used to represent growth and steady state phenomena in hydrology are reviewed. It is shown that there are essentially two types of growth models possible; the cyclic growth model and the random configuration model. For steady state phenomena (time series) we are generally restricted to a Gaussian type of model with or without autocorrelation. Self‐similarity models (fractional Brownian motion) lead to physically absurd conditions if they are extrapolated to high frequencies.
Two‐Dimensional Dispersion Experiments in a Porous Medium
Authors: Bruch John C.
Published: February 2008

A series of two‐dimensional dispersion experiments were performed in a one and two layered porous medium. The experimental results were compared with a theoretical and a numerical solution both of which describe the two‐dimensional dispersion of a miscible, second fluid through a unidirectional, seepage flow. The combined effect of longitudinal and lateral dispersion was considered in all cases. The experiments clearly, verified the theoretical and the numerical results.
Extraction Term Models of Soil Moisture Use by Transpiring Plants
Authors: Molz F. J. , Remson Irwin
Published: February 2008

A mathematical model is developed describing moisture removal from soil by the roots of transpiring plants. The model uses a macroscopic extraction term in the one‐dimensional soil moisture flow equation. It describes both moisture removal by the plant and induced moisture movement through the soil. A numerical procedure based on the Douglas‐Jones predictor‐corrector method is used to solve the model, and solutions are compared with experimental data. The results indicate that extraction term models are computationally and physically feasible and give insight into the mechanics of the overall moisture extraction process.
An Improved Method for Size Distribution of Stream Bed Gravel
Authors: Leopold Luna B.
Published: February 2008

Random sampling of surface rocks on a gravel bar is biased toward larger sizes which, because of their area, are more likely to be picked up. Weighting can eliminate this bias. Data on average weight of a single rock are used to change numbers of rocks to weights, thus yielding size frequency data in general agreement with a sieved and weighed sample. The question of what to sample depends on the use to which the data are to be put, and is not treated in detail in this paper.
A Comparison of Energy Balance Methods for Estimating Atmospheric Thermal Radiation
Authors: Cooley Keith R. , Idso Sherwood B.
Published: February 2008

A radiation balance method and a modified radiation balance method were used to determine hourly and daily values of atmospheric thermal radiation on three clear and three cloudy days during February and March 1970 at Phoenix, Arizona. The radiation balance was used over surfaces of bare soil, Bermuda grass, and open water; whereas the modified radiation balance was used over the open water surface only. The modified radiation balance differed from the pure radiation balance method in that net radiation was calculated as the residual in the energy equation rather than measured.

The values of atmospheric thermal radiation thus obtained were compared to valuesobtained from measurements of incoming, all‐wave radiation minus incoming solar radiation.From this analysis it appeared that the best alternative to the semi‐direct measurementof atmospheric thermal radiation was the radiation balance over the bare soil surface.Results from this method were of sufficient accuracy, even on an hourly basis, for mostresearch studies, and were even better on a daily basis. Radiation balances over grass andwater surfaces were somewhat less satisfactory, but still better than the modified radiationbalance method.
Steady State Flow around a Well in a Two‐Layered Aquifer
Authors: Khan Muhammad Yunus , Kirkham Don , Toksöz Sadik
Published: February 2008

Theoretical expressions for the hydraulic head and the stream function are derived for three‐dimensional, axisymmetric steady flow around a well in a two‐layered aquifer. The aquifer receives a steady vertical recharge, and the well is pumped at a constant rate; the hydraulic head at the outer cylindrical boundary is kept constant. Two sets of flow nets and a table of values are presented to show the effect of hydraulic conductivities of the two layers on flow lines, equipotentials, and the height of the water table. Graphs showing the effect of the problem variables on the height of the water table are presented.
Influence Chart for Regional Pumping Effects
Authors: Germán E. , Figueroa V.
Published: February 2008

An influence chart is presented that, within its own limitations, makes possible the calculation of the regional effects of pumping without the help of analog or digital models.
A Gamma Attenuation Unit and Logistic System for Monitoring Water Content of Large Soil Columns
Authors: Cassell D. K. , Nielson D. R.
Published: February 2008

A gamma radiation attenuation unit was designed to monitor water contents of large cores of natural soil. A logistic system was developed that allows one person easily to maneuver and monitor soil cores as large as 1 foot in diameter and feet in height.
Comments on the Stable Isotope Method in Regional Groundwater Investigations
Authors: Gat Joel R.
Published: February 2008

Natural variations of oxygen 18 and deuterium abundances in groundwaters, as compared to the local precipitation, are discussed as a hydrologic tool. It is shown that the residual scatter in time and space of the isotope content of groundwater sources is a measure of the homogeneity of these systems rather than of their age or size and that the concept of a regional slope of evaporation lines on the δD–δ18 O diagram has only limited validity. Isotope criteria are suggested for distinguishing rainfall from past periods of different climate from present rainfall. It is concluded that as a result of the unsteady nature of the mechanisms affecting the isotope composition of groundwaters, their most reliable use, under the limitations of our present quantitative knowledge on the causes of this scatter, is as classifying parameters in regional investigations.
Model Flow Duration and Streamflow Variability
Authors: Singh Krishan P.
Published: February 2008

A simple flow duration model is postulated by using data from 120 gaging stations in Illinois. On the basis of model flow duration, a region can be divided into hydrologic divisions. For each division, the coefficient and exponent in the model have distributions with respect to percent time. The variations in the coefficient and exponent are explained in terms of areal and physiographic factors. An objective method is presented for deriving flow duration of an ungaged stream in a hydrologic division by using model flow duration.
Hydrogeologic Factors Influencing Well Yields in Folded and Faulted Carbonate Rocks in Central Pennsylvania
Authors: Siddiqui S. H. , Parizek R. R.
Published: February 2008

Hydrogeologic factors influencing well yields in folded and faulted Cambro‐Ordovician carbonate rocks and shales were investigated in central Pennsylvania. Productivity values (in gallons per minute per foot of drawdown per foot of saturated thickness) were obtained from 80 wells, the geometric mean value being 19.00, and were grouped into various categories according to well location. Productivities for the various categories were ranked and plotted against the percentage of wells on logarithmic probability paper. Parametric and nonparametric statistical tests were applied; the results of the nonparametric tests are presented. Fracture trace wells were more productive than nonfracture trace wells. Accidentally located fracture trace wells were as productive as intentionally located fracture trace wells because the accidentally located wells were clustered in more productive rocks. The success ratio of accidentally locating a fracture trace well is 4:6. Wells in sandy dolomite and coarse‐grained dolomites were the best producers; wells in valley bottoms were more productive than those in valley walls and uplands; anticlinal wells were better producers than synclina wells; and wells in beds dipping at less than 15° had higher yields than others. The Upper Sandy dolomite member and the Nittany dolomite have similar aquifer characteristics, which are significantly different from those of Bellefonte dolomite, limestones, and shales.
Recurrence intervals between exceedances of selected river levels: 4. Seasonal streams
Authors: Woodyer K. D. , McGilchrist C. A. , Chapman T. G.
Published: February 2008

Seasonality in stream behavior, as expressed by the frequency of exceedance of selected river levels, is determined by a simple test. The previously developed nonseasonal point and interval estimates for the mean recurrence interval between exceedances are found to be robust for all 70 seasonal streams tested. The estimates are not improved by the additional information in a multiplicative model based on relative constancy of the seasonal pattern over the range of upper river levels.
Benefit‐accuracy relationship for small structure design floods
Authors: Wilson Kenneth C.
Published: February 2008

One important function of a hydrometric network is to provide estimates of flood flows for use in the design of small flood control structures. It is demonstrated that the optimum design flow for such structures can be obtained by setting up appropriate functional relationships for the construction cost and the cost of probable future damage and then differentiating. By expressing cost and discharge as ratios of the values at the optimum point, a dimensionless equation has been derived to link the error in flood flow estimates to the resulting increase in the cost of flood control. When the error in flood estimation is not excessively large this cost‐accuracy relationship reduces to a simple square law. It is shown by example how the required coefficients can be determined for representative cases, and the application of the method to network planning is indicated.
Sensitivity of reservoir design to the generating mechanism of inflows
Authors: Wallis J. R. , Matalas N. C.
Published: February 2008

The design capacity of a reservoir depends on the generating mechanism of the inflows. If one uses the sequent peak algorithm in a deterministic manner, the minimum capacity λm required to meet a specified level of demand α is shown to depend on α and the values of the lag 1 serial correlation coefficient ρ and the Hurst coefficient h of the inflows. Although these experimental results may not realistically describe the ranges of the values α, ρ, and h over which other objective functions can be expected to be sensitive to the flow generating model, they do indicate that such ranges exist and that one may have to consider carefully both the list of moments to preserve and the means for their unbiased preservation.
River Dee Research Program: 3. A short‐term control strategy for multipurpose reservoir systems
Authors: Jamieson D. G. , Wilkinson J. C.
Published: February 2008

An automated control strategy has been developed for the short‐term operation of multipurpose reservoir systems that will act as the basis for on‐line processing of data obtained from a sophisticated telemetry scheme. The action of the computer will be (1) to interrogate the outstations via the telemetry scheme to establish the existing state of the water resource system, (2) to forecast the future state of the system, and (3) to decide the optimal releases from the multipurpose reservoirs. The real‐time forecasting stage uses digital simulation, and the decision‐making stage is based on a dynamic programing formulation.
watershed physics: Soil variability criteria
Authors: Rogowski A. S.
Published: February 2008

Variability criteria for input parameters to the moisture characteristic and hydraulic conductivity models are developed. The parameters include the water contents at air entry and at 15 bars as well as the hydraulic conductivity used in matching the predicted values with the experimental values at saturation. The available data suggest that the water contents at 15 bars and at air entry have a normal distribution whereas the hydraulic conductivity has a log normal distribution. The distributions of water contents and conductivities for different soil series with depth and over an area are illustrated, and variability is expressed as the coefficient of variation. It is suggested that in watershed studies a soil be considered uniform with depth or over an area if the coefficient of variation with respect to water content does not exceed 15% at 15 bars and 10% at air entry and the logarithmic standard deviation for hydraulic conductivity used in matching is less than log 2. If the preceding conditions are met, the water contents at 15 bars and at air entry as well as the saturated conductivities may be averaged.
Delineation of areas for terrestrial disposal of waste water
Authors: Bond John G. , Williams Roy E. , Shadid Omar
Published: February 2008

The disposal of municipal, industrial, and livestock waste waters into the Snake River and its tributaries is the source of a serious surface‐water pollution problem in the southern part of Idaho. At places waste water is also a threat to the groundwater resource. Renovation, particularly with respect to organic and nutrient constituents, through irrigation with coincidental crop fertilization and groundwater recharge is proposed for hydrogeologically suitable portions of the Snake River plain, instead of expensive tertiary or sometimes secondary treatment. The region near Idaho Falls and Blackfoot has been used as a case study area to establish the methodology for selecting the most suitable terrestrial disposal sites. The procedures used are sufficiently straightforward; thus they are readily adaptable to other larger areas. Safeguarding surface water and groundwater resources, providing for maximum probability of proper renovation of waste water, and minimizing design and supervision requirements are conditions that must be satisfied by any terrestrial waste water disposal project. The criteria for selecting sites that meet these conditions for proper disposal and renovation include gently sloping topography, a thick subsurface section of unconsolidated, unsaturated porous medium, a surficial mantle of high sand‐silt content, and a well‐understood shallow groundwater flow system. When evaluation and mapping apply to these criteria in the area around Idaho Falls and Blackfoot, Idaho, the delineation of sections of land where successful terrestrial disposal of waste water can be expected is facilitated. The delineation of such areas permits municipalities to identify sites for terrestrial disposal of domestic waste water, and it provides industry with the opportunity to select locations for future plants from which terrestrial disposal of waste water is anticipated; such planning is essential in eliminating the nutrient enrichment of surface water bodies in the future.
Effects of exposure to sublethal DDT on the exploratory behavior of goldfish (Carassius auratus)
Authors: Davy F. B. , Kleerekoper H. , Matis J. H.
Published: February 2008

When they are introduced into a novel environment, normal goldfish display a highly specific, nonrandom exploratory behavior. It consists of a systematic spatial and temporal distribution of activity that in the light of its complexity is assumed to be under the control of the central nervous system. Aspects of this exploratory behavior are significantly affected by chronic exposure to DDT (10 μg/1 p.p.′ DDT for 4 days), and thus earlier suggestions in the literature that the pesticide may affect functions controlled by the central nervous system are reinforced. The maintenance of the fish for 20 hours in laboratory water following exposure to DDT resulted in a decrease in the described DDT effect.
Calibration of distributed parameter groundwater flow models viewed as a multiple‐objective decision process under uncertainty
Authors: Neuman Shlomo P.
Published: February 2008

Owing to the deterministic nature of most groundwater flow models there has been a tendency in the past to overlook the strong element of uncertainty that invariably enters into the problem of parameter identification. It is shown that because of this uncertainty an approach based on the minimization of a single error functional does not in general lead to satisfactory results. A multiple‐objective decision process is postulated taking into account all the available information on the aquifer flow system as well as the range of environmental conditions under which the system is expected to operate in the future. According to this new approach a continuous or discrete set of alternative solutions to the identification problem is generated with the aid of mathematical programing techniques, and the decision maker is asked to apply his own value judgment in selecting a particular model structure. The method is illustrated by applying parametric linear programing to a finite element model of steady state flow in a locally anisotropic aquifer. The reliability of each parameter estimate is ascertained with the aid of a postoptimal sensitivity analysis.
On the uptake of tritium by soil water and groundwater
Authors: Ehhalt D. H.
Published: February 2008

Tritiated molecular hydrogen in the atmosphere is oxidized by soil microorganisms and may contribute to the T input into soil with a rate of 5.4 T atom/cm2 sec.
A stochastic model for daily river flows in an arid region
Authors: Yakowitz Sidney J.
Published: February 2008

We propose a model for daily river flow that differs from approaches (some of which are described herein) taken by other authors in that the flow on any day is a nonlinear function of previous flows plus a random component. Thus the theory of second‐order time series analysis plays no role here. Additionally, ideas from meteorology are incorporated, and the random component is taken to be a Markov process (the transition matrix being dependent on the month of the year), arid thereby droughts, rainy periods, and seasonal variation are incorporated into simulated trajectories. In particular, by proper choice of the random component, sample trajectories exhibit episodes of zero flow such as those that characterize rivers in arid lands, drainage networks, and storm sewers. The statistical and computational properties of the model are explored as we estimate the parameters of the Rillito River and subsequently simulate flows. Then the simulated trajectories are compared to the actual Rillito River streamflow record.
Modified approach to capillary hysteresis based on a similarity hypothesis
Authors: Mualem Yechezkel
Published: February 2008

We present herein a simplified approach to the capillary hysteresis phenomenon. This approach is based on a similarity hypothesis resembling that of Philip (1964), but different basic assumptions lead to a quite simple and handy method of predicting the relationships between the capillary head and the water content within the hysteretic loop. Only the boundary curves of the main loop are required in order to derive analytically the scanning curves. The reliability of the proposed modified model is demonstrated by a comparison of the predicted scanning curves with the measured ones. The computed results are often in more satisfactory agreement with experiments than those obtained with the use of the general Néel‐Everett model.
A study of evapotranspiration from a Douglas fir forest using the energy balance approach
Authors: McNaughton K. G. , Black T. A.
Published: February 2008

Energy balance measurements of evapotranspiration from a young Douglas fir forest are reported for a period of 18 days in July 1970 when soil water was not limiting. Peak daily evapotranspiration rates characteristically occurred 2–3 hours after solar noon, and evapotranspiration showed a short‐term independence from net radiation. This behavior is interpreted as being a consequence of the large forest roughness. Daily evapotranspiration and net radiation were, however, well correlated. Values of surface diffusion resistance calculated from Monteith's combination formula are presented. Daytime values showed significant day‐to‐day differences, and an attempt to define a potential evapotranspiration rate by assuming a constant daytime surface resistance was not successful. Comparison of evapotranspiration measurements with a potential evaporation formula for wet surfaces developed by Priestley and Taylor suggests that evaporation of intercepted water proceeds 20% more rapidly than evapotranspiration from the nonwetted canopy.
Fog drip from artificial leaves in a fog wind tunnel
Authors: Merriam Robert A.
Published: February 2008

The effect of fog intensity and leaf shape On water storage on leaves was studied by using a simple fog wind tunnel and leaves of aluminum and plastic. Test equipment was designed to allow quantification of the chosen variables rather than to duplicate natural conditions. Two intensities of fog were produced, and drip was measured from leaves of five different shapes. Fog intensity effects tended to obscure weaker leaf shape effects in the tests. Drip measurements were reasonably close to values predicted by calculation using an exponential equation based on fog flow and leaf storage capacity. Results indicate that the method of estimating fog drip could be useful when appropriate climatic and vegetative characteristics are known.
An experimental study of immiscible displacement with an unfavorable mobility ratio in porous media
Authors: Gupta Surendra P. , Greenkorn Robert A.
Published: February 2008

The displacement of one fluid by another (miscible or immiscible) in porous media is an important phenomenon that occurs in groundwater movement and oil reservoir engineering. Practical examples are water flooding, solvent flooding, saltwater intrusion into coastal aquifers, and coning. Experiments are presented on viscous fingering in a glass bead packed porous medium model. They cover the entire scope of finger development from the incipient fingers predicted by Chuoke's theory to a parallel‐sided single finger. As incipient fingers move, they decrease in number. Both decay and merging are simple viscous effects. Results of several experiments show that the rate of growth develops almost immediately, well before the finger is parallel sided. The mechanisms of wavelength generation and degeneration are discussed on physical grounds.
Concepts of mathematical modeling of sediment yield
Authors: Bennett James P.
Published: February 2008

A deterministic structure imitating a sediment yield model should mathematically approximate the behavior of two distinct phases of the phenomenon, the upland phase and the lowland channel phase. For upland erosion, research is most needed in quantifying gully erosion, whereas for lowland streams it is most needed to explain the influence of meanders on bed material transport and to develop a floodplain accounting component. In both phases, research is needed to explain the effects of unsteadiness and flow nonuniformities on transport. Sensitivity analysis studies of sediment yield models are needed to illustrate how well the models can be calibrated and what output precision can be expected from input data with known statistical characteristics. Present estimates indicate that although a regression of annual sediment discharge on annual water discharge might be expected to give a prediction within 20% of the observed value, even a well‐calibrated digital model might give an error greater than 40% for a single storm on a small watershed.