bluuebunny/crossref_metadata_2025 huggingface dataset:
Final Relative Sunspot‐Numbers for 1943
Authors: Brunner W.
Published: February 2008

Table 1 contains the final sunspot‐numbers for 1943, for the whole disk of the Sun, based on observations made at the Zürich Observatory, supplemented by series furnished by other cooperating observatories for days (indicated by asterisks) on which no observations were possible at Zürich.

Table 2 gives the yearly means of the relative numbers, R, since the last minimum 1933 and the number of days without spots.
Magnetic Data, Cape Town and Hermanus Magnetic Observatories, 1940–1942
Authors: Ogg A.
Published: February 2008

The Cape Town Magnetic Observatory, which was established for the Polar Year 1932–1933, was unsuitable as a permanent observatory owing to magnetic disturbances caused by the electric railways. The observatory, however, continued in operation until the end of 1940, when a new observatory at Hermanus was ready for work.

Table 1 gives the mean yearly values of the magnetic elements at the Magnetic Observatory, Hermanus, for the years 1941 and 1942, and also gives the relation between these and the Cape Town values for the years 1933–1940, which were published in this JOURNAL September 1941, p. 364.
Diurnal‐variation anomalies at Tucson
Authors: Rooney W. J.
Published: February 2008

The seasonal changes in diurnal variation at Tucson are of unusual interest because of the location of the observatory in the transition‐belt where the type of diurnal variation changes markedly during the year. Monthly hodograms of the diurnal variation in earth‐current potential‐gradient indicate that its changes are in general consistent with the recognized movement of the current‐systems in the ionosphere northward and southward with the Sun. Two definite anomalies, less readily explained, are found to exist. The first is a marked increase in activity in January, appearing as a large increase in amplitude, and the second consists of a decrease and irregularity in the eastward component during March. Corresponding anomalies are found in the magnetic diurnal variation. In January, that of the total force, F, is increased to a value well above its mean winter level, with X, Y, and Z all showing approximately the same change in percentage. In March only X is abnormal and, like the eastward earth‐current component, its diurnal variation is small and irregular. The winter anomaly might be accounted for by assuming the existence of a zone of unusually high conductivity in the ionosphere, into which the current‐system passes at its southern‐most position. The anomaly in March may be due to erratic shifting of the latitude of the current‐center to the northward such as that deduced by Hasegawa from the records at Japanese stations.
The Magnetic Observatory at Manhay
Authors: Harradon H. D.
Published: February 2008

The participation of Belgium in the Second International Polar Year, 1932–33, was marked by the establishment of two magnetic observatories, one at Manhay (Province of Luxembourg, Belgium) and the other at Elisabethville (Belgian Congo). The site of Manhay, 45 km from Liège on the height of land between the valleys of the Ourthe and the Amblève and about 15 km distant from each stream (latitude 50° 17.′9 north, longitude 5° 40.′9 east) seemed very suitable for a permanent observatory destined to replace the observatories of Uccle and Cointe, long ago rendered useless by the encroachments of electric tram‐lines.

The construction of the building for the Manhay Observatory was completed at the end of July, 1932. The installation and adjustment of the variometers occupied the whole of the month of August. The station was ready for operation by September 1, but the absolute hourly values of the horizontal and vertical components could not, for various reasons, be satisfactorily obtained until towards the end of 1932. The magnetic results for Manhay for the International Polar Year 1932–33 were published in 1937.
The fiftieth year of the Journal, 1945
Authors: Chapman Sydney
Published: February 2008

Workers on geomagnetism and its allied sciences owe a well‐recognized debt to Terrestrial Magnetism, which has so greatly aided progress in these branches of knowledge. It has provided a focus and a forum particularly necessary and valuable for such a group of borderland subjects. Previously work in these fields was published in a host of periodicals and in many countries, and few workers had ready access to them; too often even the existence of important papers might long remain unknown to researchers in cognate fields. These difficulties have not been and could not be entirely removed by this quarterly, but they have been greatly diminished, and not least by its “Reviews of publications,” started in the first issue, and the “List of publications,” begun in the second issue.
Effects on the ionosphere at Huancayo, Peru, of the solar eclipse, January 25, 1944
Authors: Ledig P. G. , Jones M. W. , Giesecke A. A. , Chernosky E. J.
Published: February 2008

The results of the effects of a solar eclipse of magnitude 0.88 at Huancayo, Peru, on the various components of the E‐, F1‐, and F2‐layers of the ionosphere are described. Minima in ion‐density were observed for the E‐ and F1‐layers near the time of maximum eclipse. A delayed effect on the decrease of F2‐layer ion‐density was observed. An effect on F2‐layer ion‐density, which may be attributed to a corpuscular eclipse, is described. (Other suggestions regarding this effect are given in a separate report by H. W. Wells and A. H. Shapley.) The results of signal‐intensity variations, WWV, are also noted.
Persistent solar rotation‐period of 26 7/8 days and solar‐diurnal variation in terrestrial magnetism
Authors: Olsen Johannes
Published: February 2008

An examination of the daily means of the horizontal force at Godhavn Greenland, during the years 1926 to 1941 shows that there seems to exist a recurrence‐tendency for the mean values of H with a period of 26 7/8 days during that epoch, the values being rather low in the first half of the period and rather high in the latter half. The phenomenon is most pronounced during the four summer months where the values increase in a rather regular way from a minimum in the first half‐period to a maximum 40 γ higher in the last half. A further investigation shows that this variation is due to the disturbance daily variation, SD, that varies in a regular way during the period so that the amplitude for the eleventh day in the period is about four times greater than that for the twentieth day. Even when a sequence of only three days is examined it turns out that there is a systematic difference between the SD for days belonging to the eleventh‐day group and the SD for days of the twentieth‐day group. A similar recurrence‐tendency is not found at Sodankylä. The author assumes that the effect found at Godhavn is due to the fact that the maximum magnetic disturbance at Godhavn occurs at noon which implies that the maximum stream of charged corpuscles from the Sun hits a sunlit atmosphere. This phenomenon is restricted to places north of the auroral zone. The persistence of a fixed period during 15 years points to the possibility that the origin of this effect is located in a layer on the Sun with a fixed rotation‐period during a long time.
Committee to promote observations of daily variation of the horizontal magnetic force between and near the geographic and magnetic equators
Authors: Egedal J.
Published: February 2008

The work to be done by this newly‐formed Committee is indicated in Resolution No. 7 adopted at the Oslo Assembly (1948) of the International Association of Terrestrial Magnetism and Electricity. This resolution reads:

"The International Association of Terrestrial Magnetism and Electricity endorses resolution No. 14 adopted at the Brussels meeting of the Mixed Commission on the Ionosphere of the International Council of Scientific Unions, namely: 'That, in view of the remarkable geomagnetic control of F2‐layer density and the known abnormal daily variation of the magnetic force in regions where the geomagnetic and geographical equators are widely separated, efforts should be made to achieve operation, for one or two years, of a chain of ionospheric and magnetic stations across these equators near the longitude of Huancayo or in East Africa and, if possible, another chain near a place at which these equators coincide'."
Halley's earliest equal variation chart
Authors: Bauer L. A.
Published: February 2008

In Nature, of May 23, 1895, the writer made known the finding of a Halley isogonic chart in the British Museum which had apparently escaped the attention of modern magneticians and bibliographers and to which Halley himself, as far as has been ascertained, made no reference. Upon seeing the notice, Mr. Thos. Ward of Northwich, England, made known in the following number of the same periodical the fact that he likewise possessed a copy, bound up with other charts of the 17th and 18th centuries. Through his courtesy and kindness the JOURNAL is enabled to present the first facsimile reproduction, as far as known.
Relation of carbon 14 concentrations to saline water contamination of coastal aquifers
Authors: Hanshaw Bruce B. , Back William , Rubin Meyer , Wait Robert L.
Published: February 2008

Naturally occurring stable or radioactive isotopes may be used in some places to identify the origin of saline water that contaminates some coastal aquifers. In a recent study to determine the origin of saline water in the Ocala Limestone aquifer near Brunswick, Georgia, the following sources were analyzed for C14 and deuterium concentrations: potable water from the Ocala Limestone, contaminated water from the Ocala Limestone, saune water from the underlying Claiborne Group, and nearby ocean water. The chloride concentration of the groundwater ranges from about 25 ppm in the potable water to more than 2000 ppm in the deeper part of the Claiborne Group. From an interpretation of piezometric maps and other hydrologic data, previous investigators had concluded that the source of the contaminating water was the Claiborne Group and not the nearby ocean. The essentially uniform range of low values of −965 to −987‰ of the modern standard (National Bureau Standard C14 oxalic acid) for the C14 activity of the groundwater samples (regardless of the degree of contamination) is in agreement with this conclusion. If recent ocean water, which had a C14 value of +285‰, were the source of contamination, the contaminated water would have had a C14 activity higher than the activity of the fresh water. Deuterium analyses are not inconsistent with the interpretation that water from the Claiborne Group, rather than recent ocean water, is the source of the contaminating water. The concurrence of the hydrologic and the isotopic data in this area where the hydrology is well known suggests that isotopic analysis may be used to identify the origin of water in different portions of a hydrologic environment.
Variation of the permeability tensor ellipsoid in homogeneous anisotropic soils
Authors: Liakopoulos Aristides C.
Published: February 2008

The flow of water through a homogeneous anisotropic soil is governed by Darcy's equation in which the velocity is proportional to the imposed hydraulic gradient. The constant of proportionality (coefficient of permeability) is a symmetric tensor of second rank, reducing to a scalar only in the case of isotropic soils. It is shown that for determining the velocity vector from a known hydraulic gradient the permeability tensor ellipsoid should be constructed with semiaxes equal to the inverse of the square root of the permeability values. For determining the hydraulic gradient from a known velocity, the permeability tensor ellipsoid should have semiaxes equal to the square root of the principal permeability values. The fact that two different tensor ellipsoids can be constructed for a given anisotropic soil may produce confusion and give rise to a significant error. Special attention should therefore be given in evaluating the appropriate permeability value to be used in Darey's equation. It is recommended that the ellipsoid used always be the one with semiaxes equal to the inverse square root of the principal permeability values. Permeability tests were conducted on anisotropic sandstone. Cylindrical cores were taken at various directions with respect to a fixed coordinate system, and permeability values were determined in a constant‐head permeameter. The values obtained when plotted on polar coordinate paper result in a two‐dimensional permeability ellipse. The necessary graphical constructions for determining the direction of the velocity or the direction of the hydraulic gradient from the corresponding tensor ellipses are also given.
Viscous model study of sea water intrusion in water table aquifers
Authors: Columbus Nathan
Published: February 2008

An equation is developed for the length of sea water intrusion under conditions of steady‐state flow in unconfined coastal aquifers. A viscous flow model is used to verify the equation for the length of salt water intrusion. Figures are constructed to show the relationship between theoretical curves and experimental data. The experimental results are conclusive in proving the validity of this equation. The equation appears to be valid even when the Dupuit assumptions are no longer valid. It is conjectured that this equation may be rigorously valid in spite of the fact that it is derived on the basis of several simplifying assumptions. The theoretical profiles of the fresh water‐salt water interface reproduce closely the observed profiles. It is observed that salt water moves toward the outlet along the zone of diffusion toward the outflow section. This observation confirms previous flow‐net analysis.
Some observations on the hot springs of central Chile
Authors: De Grys Ann
Published: February 2008

The Cordilleran hot springs of central Chile can be divided into four groups: (A) Pre‐Cordillera springs of variable composition emerging from continental sediments and andesites. Temperature ranges from 22 to 30°C. (B) Inner Cordillera springs found along a zone of structural weakness indicated by the presence of volcanoes and faults. The waters are rich in Ca, Mg, HCO3, and SO4, and minor elements, Sr, B, V, and Ti derived from marine sediments containing limestone and gypsum deposits. Some of the springs have considerable amounts of Fe and Mn. Temperatures are variable, ranging from 30 to 80°C. (C) Sulfuric‐acid type springs with a temperature of about 85°C.‐These waters leach Fe, Mn, and Al from the rocks. (D) Dilute NaCl springs in the batholith with temperatures ranging from 40 to 75°C. All the springs are near volcanic centers. The origin of the water is discussed, but not all the springs are considered to have contributions from magmatic sources. Some variations in the discharge occur, but the temperature and comparison, so far as can be ascertained, are constant.
Determination of Columbia River flow times downstream from Pasco, Washington, using radioactive tracers introduced by the Hanford reactors
Authors: Nelson Jack L. , Perkins R. W. , Haushild W. L
Published: February 2008

Radioactive tracers introduced into the Columbia River in cooling water from the Hanford reactors were used to measure flow times downstream from Pasco, Washington, as far as Astoria, Oregon. The use of two tracer methods was investigated. One method used the decay of a steady release of Na24 (15‐hour half‐life) to determine flow times to various downstream locations, and flow times were also determined from the time required for peak concentration of instantaneous releases of I131 (8‐day half‐life) to reach these locations. Flow times determined from the simultaneous use of the two methods agreed closely. The measured flow times for the 224 miles from Pasco to Vancouver, Washington, ranged from 14.6 to 3.6 days, respectively, for discharges of 108,000 and 630,000 ft3/sec at Vancouver, Washington. A graphic relation for estimating flow times at discharges other than those measured and for several locations between Pasco and Vancouver was prepared from the data of tests made at four river discharges. Some limited data are also presented on the characteristics of dispersion of I131 in the Columbia River. (Keywords: Radioactivity; time of flow; Columbia River.)
Asymmetry between bribes and charges
Authors: Kamien M. I. , Schwartz N. L. , Dolbear F. T.
Published: February 2008

A classic and increasingly important example of the technological externalities problem is that of a firm discharging waste into a stream, thereby inflicting damages on down‐stream users of the water. As long as there is no economic or legal incentive to do otherwise, the firm will ignore the effects of this action on others. It has been argued that, asymmetries in income distribution and administration aside, the levying of a charge and the payment of a bribe are symmetric means of internalizing to the firm the externality resulting from its discharge of waste into the stream. It is shown that this symmetry between bribes and charges does not hold when the cost and revenue functions are subject to change, unless these functions are known by the affected parties. Furthermore, a bribe will not only cause the firm to produce at least as much waste matter as under a charge alternative of the same cost but may even induce the firm to produce more waste matter than in the absence of a bribe or a charge. Our analysis deals with water pollution for the sake of exposition; the analysis can be extended readily to other situations giving rise to externalities.
Determining the average porosity and permeability of a stratified aquifer with the aid of radioactive tracers
Authors: Mercado A. , Halevy E.
Published: February 2008

A tracing technique for determining the average porosity and the permeability of the various layers of a stratified aquifer is presented. The average porosity and the different permeabilities of the four layers of a shallow sandstone aquifer were determined by tracing a pulse of K3Co60 (CN)6 between two wells located 15 meters apart, as well as by using standard pumping‐test techniques. The results were confirmed by the salinity balance of the aquifer. The experiment has indicated the usefulness of radiotracer techniques combined with standard pumping techniques and chemical analyses for the study of microstructural properties of sandstone aquifers. (Key words: Permeability; porosity)
Probabilistic models for predicting stream quality
Authors: Loucks D. P. , Lynn W. R.
Published: February 2008

Mathematical models are developed to predict the probability distribution of minimum dissolved oxygen concentrations occurring downstream from any particular wastewater treatment facility. Each of the models is based on different assumptions of average daily stream and sewage flow conditions. Using a hypothetical example, distributions of minimum dissolved oxygen concentrations in a stream are determined for 1, 2, and 3 consecutive‐day periods. Knowledge of the cost required to reduce the probability of having less than some desired level of stream quality for various consecutive‐day periods can be used as a basis for selecting the degree of wastewater treatment as well as for establishing more realistic stream quality standards. (Key words: Quality of streams; probabilistic models)
An evaluation of the effect of groundwater pumpage on the infiltration rate of a semipervious streambed
Authors: Moore J. E. , Jenkins C. T.
Published: February 2008

A quantitative evaluation of the effect of ground water pumpage on the Arkansas River in southeastern Colorado using both groundwater and surface‐water data has shown that, in at least one reach of the valley, pumping has lowered the water table below the level of the apparently pervious streambed, thereby breaking the hydraulic connection between the stream and the water table. The river is gaining except in reaches where withdrawals of water from the valley fill are large. However, a large cone of depression has formed directly beneath the stream because of continuous withdrawal of about 10 cfs of groundwater at Lamar. The cone extends under the losing reach of the stream without appreciable distortion and has been as much as 12 feet below the streambed. In the 1‐mile reach immediately upstream from the wells, the stream lost about 2 cfs during each of three sets of observations. Once the water table is lowered below the streambed, hydraulic connection is broken, and changes in depth to water table have no measurable effect on the rate of depletion of streamflow. The major control on infiltration loss, where hydraulic connection is broken, is probably the permeability of the least permeable layer of the streambed. Studies of stream reaches that have beds with wide ranges of grain size and sorting suggest that the range in maximum infiltration rates is small if the streambeds are undistributed and depth of water in the stream is less than about 1 ft. A maximum infiltration rate of 20 gal/ft2/day is suggested as a reasonable first approximation in the absence of observed rates.
Rainfall distribution over dissected terrain in southwestern Wisconsin
Authors: Sartz Richard S.
Published: February 2008

Rainfall studies on the Coulee Experimental Forest in southwestern Wisconsin have shown that the dissected terrain of the area has only a small effect on annual point rainfall. On a steep ridge, rain gages on the windward side caught 3% less rain than gages on the leeward side. The difference for the storms of 0.5‐inch precipitation or more was only 2%. A comparison of rainfall caught by ridge and valley gages indicated that ridge gages tended to catch more, but these differences were also small. Thus, rainfall on the experimental forest varies from place to place, but the differences probably result more from normal storm variation than from topographic effects per se.
Cloud seeding trials in the rainy belt of western Colombia
Authors: Lopez Manuel E.
Published: February 2008

Evaluation of a rain stimulation operation for the Río Anchicayá, near Buenaventura, Colombia, during ‘dry’ seasons since 1963 was hampered by lack of rainfall data. Daily streamflow data were manipulated to remove serial correlation and to derive a series of daily equivalent rainfalls by comparing each day's runoff with the maximum corresponding runoff decrement observed on rainless days. The Bayes criterion, applied to frequency distributions of equivalent daily rainfall before and during the seeding, consistently recommended continuation of the seeding. The total equivalent rainfall per month was found to correlate well with the number of days per month with equivalent rainfall above 2.5 mm, and comparison of the seeded period with the regression of equivalent rainfall per month on number of rainy days per month for unseeded history indicated an increase of 13%, with one chance in 8 of random occurrence, corresponding to 2100 kw added power generation and about a sixfold economic return.
Similarities between flood control problems and other aspects of water management in the United States
Authors: Walker William R.
Published: February 2008

Until the Federal Flood Control Act of 1936, very little activity was directed toward minimizing floods and reducing flood damage in the United States. Flooding in certain areas was considered something that must be endured like the weather. Most of the effort expended to reduce damage was by small groups and individuals and had very little effect. Since 1936, the Federal Government has spent large sums of money annually to control and minimize the effect of floods, yet flood damage continues to rise.
Viewing water renovation and reuse in regional water resources systems
Authors: Frankel Richard J.
Published: February 2008

In planning regional water resource systems, water renovation and reuse on a large‐scale basis are virtually disregarded as serious alternatives to pollution abatement for future water use requirements. Where projects are wholly federally planned, the chief reason for this situation stems from current policy, which authorizes low‐flow augmentation as the sole tool of water quality management available to river‐basin planners on a nonreimbursable basis. This institutional constraint has introduced serious inefficiencies into federal expenditure programs for quality improvement [Davis, 1966; Natl. Acad. Sci., 1966].

No public measures currently exist to induce municipalities to reclaim wastewaters, and if the only beneficiaries are downstream water users, the municipalities themselves are unwilling to take action. However, by enforcing high effluent standards and thereby forcing municipalities to expend large sums in waste treatment, pollution control agencies have improved the prospects for wastewater reclamation. Obviously, with sale of reclaimed effluent for water supplies or reutilization of reclaimed waters for recreation, upstream as well as downstream communities can benefit greatly through reclamation measures.
Recreation benefits from water pollution control: A further note on benefit evaluation
Authors: Stevens Joe B.
Published: February 2008

In my recent paper [Stevens, 1966], estimates of demand functions and angling ‘success elasticities’ were presented for three sport fisheries as a methodological basis for determining recreation benefits from water pollution control. By utilizing success elasticities to shift the demand function for one of the fisheries (D0 to D1 in Figure 1), it was possible to argue that anglers would supply themselves with a lesser quantity of angling at some reduced level of angling success. If the reduced quantity of angling effort (S1) were to be rationed among the original users (D0), a price of AB would be expected. Accordingly, benefits from preventing water pollution would accrue from avoiding this leftward shift of the demand function.
The growth and development of attached stream bacteria, Part 1. Theoretical growth kinetics of attached stream bacteria
Authors: Sanders Walter M.
Published: February 2008

The growth rate of slime bacteria is limited when the attaching surface becomes completely covered with one layer of cells. At this point, the increase in mass of organisms shifts from logarithmic to linear with respect to time. A second growth limiting factor occurs when the thickness of the slime mass exceeds the limiting thickness for the diffusion of oxygen. From this point on, the rate of oxygen consumption will remain constant with respect to time. The maximum rate of nutrient removal from the substrate will occur when the slime thickness equals the limiting thickness for the diffusion of oxygen.
Six federal reclamation projects and the distribution of income
Authors: Freeman A. Myrick
Published: February 2008

The major concern of this paper is the effect of Bureau of Reclamation Irrigation Projects on the size distribution of income and means of evaluating these effects. Estimates of the before and after project distributions of income for six recent projects are provided. These estimates are based on Bureau data on the sizes of project farms and on benefit and cost data revised by the author. A social welfare function incorporating income distribution is used to calculate welfare‐weighted benefit‐cost ratios for comparison with the revised efficiency benefit‐cost ratios normally used in project evaluation. All projects were redistributing income in the ‘right’ direction. However, only one of the six projects had a welfare‐weighted benefit‐cost ratio greater than 1. (Key words: Agriculture; economics; planning; resources; water management; water resources)
When is it safe to extend a prediction equation?—An answer based upon factor and discriminant function analysis
Authors: Wallis James R.
Published: February 2008

Prediction equations for hydrologic events developed from one population of observations (watersheds) are often solved for another population that is removed either in time or in space. Predictions of this kind are never certainties, although some predictions are obviously more uncertain than others. This paper proposes an empirical uncertainty classification that may be found useful for separating probably successful from probably unsuccessful extensions of prediction equations. The classification system is illustrated by a prediction equation for suspended sediment discharge developed from some watersheds in California, and by a discriminant function for marine versus nonmarine sediments based upon microelements. (Key words: Statistics; principal components analysis; linear discriminant functions).
Accuracy of discrete models used to predict estuary pollution
Authors: Leeds J. V.
Published: February 2008

In the solution of estuary pollution problems, the mathematical model is a partial differential equation, which is often replaced by a set of ordinary differential equations with time as the independent variable. The solution to these equations is taken as the solution of the partial differential equations at points dx apart. A significant problem is to determine the closeness of the solution of the ordinary differential equation to the solution of the partial differential equation, the spacing dx, and the number of sections. The closeness of the solution can be judged by examining the magnitude and phase of the frequency response of the partial differential equations and the set of ordinary differential equations. Selecting a given phase error allows one to obtain a relation giving the allowed spacing dx. Selecting an attenuation error sets the number of sections. Thus, from the knowledge of the frequency response of the system the rules developed give the number of sections and spacing to meet specified errors in the approximation. (Key words: Computers, digital; estuaries; frequency analysis; pollution; quality of water)
Hydrologic data collection in tidal estuaries
Authors: Gunnerson Charles G.
Published: February 2008

For predictive models, the optimum sampling interval and record length depend upon the frequencies at which significant variance is found. Estimates of spectral density, coherence, and phase relationships of stage, velocity, and salinity provide a basis for evaluating hydrologic data collection and utilization near the mouth of the Sacramento River. Here it was found that a 2‐hour sampling interval provided the essential data for engineering purposes. This interval is consistent with those found for the Potomac River estuary and for Raritan Bay, (Key words: Data; estuaries; pollution)
Flow of groundwater in relatively thick leaky aquifers
Authors: Hantush Mahdi S.
Published: February 2008

Solutions to many problems of flow in leaky aquifers are based on a differential equation that includes a leakage term in addition to the usual terms of the equation of groundwater motion. In other words, the effect of leakage on the flow is incorporated in the differential equation rather than expressed as a boundary condition, as it actually occurs in the physical system. Such an approximation is justified when the main aquifer is relatively thin, provided, of course, that the conductivity of the semipervious layer relative to those of the main aquifers of the leaky system is small. Although the latter condition is almost always prevalent in nature, the aquifers are not always relatively thin. In such aquifers, the use of the available solutions may yield poor results, especially when a quantitative criterion for the relative thickness of the aquifers is not available. Solutions are developed by using the usual differential equation of groundwater motion and the pertinent initial and boundary conditions, expressing the effect of leakage on the flow as a boundary condition. Moreover, a quantitative criterion is established for the applicability of the solutions that are already available from the approximate theory now in use. The already available solutions appear to be applicable wherever b/B < 0.10, where b is the thickness of the main aquifer, and
is the leakage factor; T is the transmissivity of the aquifer; and (K′/b′} is the leakage coefficient of the flow system. (Key words: Groundwater; hydrologie systems; leaky aquifers; seepage; wells)
Recovery of bacterial pathogens from high quality surface water
Authors: Fair J. F. , Morrison S. M.
Published: February 2008

An investigation of the presence of enteric disease producing bacteria in a high quality mountain stream in Colorado yielded 11 isolants of members of the genus Salmonella and 51 isolants of organisms belonging to the Arizona group. An improved method for the recovery of these organisms from high quality water was developed and used successfully in the study. The presence of these potentially pathogenic bacteria, which appeared to be the result of contamination by wild or domestic animals, may be a potential hazard to public health.
Linear analysis of hydrographs
Authors: Mitchell William D.
Published: February 2008

A linear hydrograph is described by the values of five parameters: the size of the drainage area (A), the amount of rainfall excess (Pe), the duration of rainfall excess (D), the translation time (T), and a storage index (k). The unit hydrograph, or any other linear flood hydrograph for a given basin, may be computed merely by incorporating the values of these parameters into a generalized, dimensionless model hydrograph.
Simplified versus optimum unit hydrographs—one comparison
Authors: Snyder Willard M.
Published: February 2008

A unit hydrograph is derived from a record storm previously analyzed for the optimum realizable unit hydrograph. The simplified curve‐fitting procedures produce a more rational appearing unit hydrograph in this case study.
Generalized estimates of free‐water evaporation
Authors: Kohler M. A. , Parmele L. H.
Published: February 2008

A modified method for deriving free‐water evaporation estimates from network observations of air temperature, dew point, wind movement, and incoming minus reflected radiation is presented. Taking into account the difference between air and water temperature in computing emitted radiation from the water surface, the expression is an improvement over the original Penman type equation where observation of net radiation over the actual water surface is lacking. The accuracy of the method depends on the applicable mass transfer wind function. Techniques are derived to adjust for the effects of advected energy and heat storage when applying the free‐water evaporation estimate to actual water bodies. Computations of lake evaporation made with the modified method for a number of locations where verification data are available indicate that the relation provides a suitable basis for estimating actual evaporation without the expense of continuous over‐water observations.
A thermodynamic analogy for meander systems
Authors: Scheidegger A. E.
Published: February 2008

A thermodynamic analogy for meander systems can be set up such that analogs of temperature, entropy, free‐energy can be defined, based on the statistical aspects of meander formation
Linear programming applied to water quality management
Authors: Revelle Charles S. , Loucks Daniel P. , Lynn Walter R.
Published: February 2008

Linear programming is applied to the management of water quality in a river basin. The charge is to select the efficiencies of the treatment plants on the river that will achieve the dissolved oxygen standards at a minimum cost. The objective function is structured in terms of the costs of the treatment plants. The principal constraints prevent violation of the dissolved oxygen standards. A simplified version of the Willamette River in Oregon is studied, using the linear programming formulation, and the results are compared with those obtained by dynamic programming. The effects of changes in the dissolved oxygen standards are explored by use of the dual variables.
Stream length and elevation for the model of Leopold and Langbein
Authors: Dacey Michael F.
Published: February 2008

A random walk formulation is given for a simple model of stream profile. The basic assumptions of the model are that in a unit of distance the elevation of the stream remains constant or drops by a unit of elevation and that the probability of each event depends upon elevation. This model is analyzed to obtain the frequency functions, means, and variances for length of stream from its origin to ‘sea‐level’ and for elevation of the stream at each unit distance from its origin.
Recurrence intervals between exceedances of selected river levels: I. Introduction and a Markov Model
Authors: McGilchrist C. A. , Woodyer K. D. , Chapman T. G.
Published: February 2008

Analysis of the frequency of exceedance of low river levels requires the examination of conditional probabilities. A first‐order Markov model is selected as a first approximation of the probability of exceedance of a selected stage for daily maximum water levels. Confidence limits are calculated on this basis.
Commentary: On the marginal cost pricing of municipal water
Authors: Bonem Gilbert W.
Published: February 2008

It has been maintained that municipal water supply should be priced so that marginal cost equals price. However, there are likely to be ‘third party’ benefits from some components of municipal water use, primarily from the use of water for landscaping and gardening. Because gardening affects the quality of the urban environment, social benefits may exceed private benefits, and marginal cost pricing may result in a price that exceeds a socially optimal price. The magnitude of divergence of the marginal cost price from the optimal price will depend primarily upon the size of the ‘third party’ benefits.
An application of principal component analysis and analysis in the study of water yield
Authors: Diaz Guillermo , Sewell J. I. , Shelton C. H.
Published: February 2008

Principal component and factor analyses were applied to annual precipitation and runoff data of fourteen watersheds from Coshocton, Ohio, and seven watersheds from Riesel, Texas. The objective was to identify the factors affecting the water yield of these watersheds and to determine the relative importance of the identified factors. From the Ohio watersheds, the rotated factor analysis suggested that watersheds area and slope were, in that order, the two most important factors affecting water yield. For the Texas watersheds, three almost equally important watershed factors were identified as the soil type, cultural practices, and land capability. A stepwise regression of runoff‐precipitation ratios of the Ohio data on area‐slope variables substantiated the effects of area and slope on runoff as determined by the factor analysis.
Discussion of ‘Interception by eastern white pine’ by J. D. Helvey and ‘Throughfall and stemflow in a pine‐hardwood stand in the Oachita Mountains of Arkansas’ by E. R. Lawson
Authors: Miller David H.
Published: February 2008

Two papers [Helvey, 1967; Lawson, 1967] on interception of rainfall in the latest issue of Water Resources Research appear to be incomplete with regard to reporting measurements of an overlooked, yet important, parameter in the interception process, i.e., the amount of rain delivered to the top of the forest stand in which measurements of throughfall and stemflow were carried out. Although the authors note that rainfall was measured in ‘openings’ or ‘clearings,’ they do not report the dimensions, shapes, or aerodynamic characteristics of these gage sites, or any of the other properties known to affect rain gage performance. Neither author ventures an opinion on how measurements made in the openings should be corrected to represent rainfall delivery at the forest top. Without this information, regrettably, Helvey has not demonstrated that ‘interception loss from white pine exceeds loss from mixed hardwoods.’ Nor has Lawson shown that ‘throughfall averaged 84.9% of gross precipitation. The remainder, of course [sic], was intercepted by the forest canopy’; nor has he shown that the throughfall equations reported are applicable even ‘to the stands studied.’ Supplying information on water input to the forest stands examined would help readers in evaluating the data presented by the authors.
The California Water Project: Is Public Decision Making Becoming More Efficient?
Authors: Brown Gardner
Published: February 2008

It is argued that the use of an incorrect discount rate, the application of procedures that overestimate net benefits, and the failure to charge a scarcity price for water are inappropriate arguments against the value of the California State Water Project. However, the existence of alternative public investment opportunities and technological progress in desalination are two factors to which the State may have given inadequate attention. As a consequence, although the State's water pricing policy encourages more efficient resource allocation than that of the federal government, there are plausible grounds for believing that further improvement is possible.
An Evaluation of the Use of Escherichia Coli Serogroups as a Means of Tracing Microbial Pollution in Water
Authors: Glantz Paul J. , Jacks Thomas M.
Published: February 2008

Escherichia coli serogroups were used as a means of tracing, and total and fecal coliform counts were utilized to determine the degree, location, and variations of, microbial pollution of water. In one area a lake served as a reservoir for the constant influx of coliform bacteria from two streams. Total and fecal coliforms increased from May through July, declined in August and September, and appeared subject to human and animal activity and weather. E. coli serogroups were traced upstream from the lake either via Paradise Creek or the Fish Hatchery, and through the Hatchery holding ponds to their spring water source. In the second study treated sewage effluent entering one of two branches of Spring Creek did not appear to furnish most of the total and fecal coliform bacteria as microbial pollution from other sources occurred. The E. coli serogroups isolated at the different sampling points were traced to their probable upstream source. The results of this study indicate that tracing microbial pollution by serologically identifying the E. coli strains is feasible.
Uniform Flood‐Frequency Estimating Methods for Federal Agencies
Authors: Benson Manuel A.
Published: February 2008

Large‐scale planning for improved flood‐plain management and expanding water‐resources development has made it increasingly important that a consistent approach be adopted for estimating flood frequencies, a major analytical component in studies required in flood‐plain management and, in a larger sense, in river‐basin management. A Federal interagency group has studied the most commonly used methods of flood‐frequency analysis and has compared the results of applying these methods to a selected group of long‐record representative sites in different parts of the country. Based on these comparisons and on other considerations, it is recommended that all government agencies adopt a uniform procedure for flood‐frequency analysis at sites where records are available. The log‐Pearson Type III distribution has been selected as the base method, with provisions for departures from the base method where justified. Continuing study leading toward improvement or revision of methods is recommended.
Statistical Properties of Stream Lengths
Authors: Smart J. S.
Published: February 2008

Two basic assumptions are employed in this treatment of the statistics of stream lengths: (1) All topologically distinct networks with a given number of sources are equally likely (after Shreve). (2) Lengths of interior links in a given network are independent random variables drawn from the same population. The mathematical development leads to an approximate expression for
that contains no adjustable parameters and that depends only on the stream numbers and the mean link length. This expression gives somewhat better agreement with data on actual stream systems than does Horton's law of stream lengths; other advantages over Horton's law are cited. Quantitatively, our procedure appears to account for about 65% of the variance in mean stream length data for third‐ and fourth‐order basins. If exact values of the link numbers are introduced into the calculation, the unexplained variance is reduced to about 15%. For a complete statistical description of stream lengths, it is necessary to know the distribution of interior link lengths. Results of computer simulation studies suggest that this distribution is negative exponential. Data taken on two small watersheds (140 links) show reasonable agreement with this hypothesis.
Influence of the Physical and Chemical Properties of Soil on Measurements of Water Content Using Neutron Probes
Authors: Cotecchia Vincenzo , Inzaghi Angelo , Pirastru Enzo , Ricchena Raffaele
Published: February 2008

The multigroup transport theory was used to study the influence of the physical and chemical properties of soil on the measurement of the water content by means of neutron probes. Calculations of the thermal neutron flux were made to examine the behavior of four soils (two of which are really rocks) frequently encountered in Southern Italy: Siliceous sand, limestone, dolomitic limestone, and terra rossa. The results show that although these soils do not contain elements with a great capture cross section for thermal neutrons (boron, chlorine, cadmium, etc.) they behave in quite different ways in the process of neutron moderation, diffusion, and capture. Hence, the response of the probe varies considerably for the same water content and dry density. Interpretation of the values obtained is thus not reliable, and the measurement of the water content by thermal neutron counts does not provide a sufficient guarantee of accuracy.
Steady Downward Flow to a Water Table
Authors: Arbhabhirama Anat , Kridakorn Chanaphan
Published: February 2008

A partially saturated zone in a porous medium is usually found above a water table when the rate of downward flow per unit area of cross section is less than the hydraulic conductivity of the porous medium. Theoretical solutions describing the distribution of capillary pressure above the water table during steady downward flow are presented. Experiments were conducted, using water as the wetting fluid and air as the nonwetting fluid, for both homogeneous and stratified media. The experimental results show good agreement with the theory. (Key words: Porous media; ground water; hydraulics).
Steady‐State Analysis in Activated Sludge Process Design
Authors: Mc Lellan J. C. , Busch A. W.
Published: February 2008

A mass balance on a completely mixed biological reactor allows several significant facts about the performance of the activated sludge process to be determined and some of the basic concepts of biological waste treatment to be illustrated. A steady‐state solution to the equation obtained from the mass balance on substrate is used to determine the reactor volume required. The governing factor in process performance is shown to be the rate at which a unit mass of organisms operates at the desired effluent substrate concentration. Examples are given to show how control of the mixed liquor suspended solids concentration can minimize or offset the effects of changes in flow and influent substrate concentration on effluent substrate concentration.
A Lag‐Deviation Method for Analyzing Channel Bed Forms
Authors: Willis Joe C.
Published: February 2008

A simple method for analyzing alluvial channel bed forms for length and time scales can be applied to records of bed elevation with either distance along the channel or time as moving bed forms pass a channel section. The difficulty of obtaining distance records of bed‐form elevation in the field is lessened by the use of simultaneous time records from two closely spaced points along the channel. Analysis of these dual records provides the dune period and propagation speed from which the dune length may be derived and permits an estimate of the ‘dune load,’ the average contribution of the moving bed forms to the bed material transport rate.