bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of hardness on the electrical and magnetic constants of steel, with particular reference to the tempering of the magnetic parts of instruments
Authors: Barus Carl
Published: February 2008

At the request of the Editor, I subjoin certain results in the tempering of magnetic needles, as obtained by Dr. Strouhal and myself some years ago. A full account of the work will be found in the Bulletin of the U.S. Geological Survey, No. 14, 1885, from which the following notes are taken.

The remarks in this memoir refer almost exclusively to the species of hardness known as temper, and which may be imparted to iron‐carburets by sudden cooling from red heat combined with more or less subsequent annealing.
Vertical Earth‐air electric currents
Authors: Bauer L. A.
Published: February 2008

It is well known that the earth's “permanent” magnetic field is a most complex one. Gauss was the first to show how to analyze this field mathematically without making any assumption with regard to the actual distribution of the magnetism within the earth's crust. For a first attempt, he found it sufficient to embrace in his analytical expression terms to the fourth order. With the exception of the first‐order terms, which represent a homogeneous magnetization about a diameter inclined to the earth's rotation axis by an angular amount of about 12°, no physical interpretation of the various terms has as yet been given.
The altitude of the aurora above the Earth's surface
Authors: Abbe Cleveland
Published: February 2008

DALTON.—In the first edition of his Essays, pages 69 and 70, Dalton says that, from observations by himself at Kendal and by Crosthwaite at Keswick, distant 22 miles, at right angles to the observed arch, the altitudes of the edge of the arch being respectively 53° and 48°, the computed altitude by the parallax method was 150 English miles. An error of 2° in either altitude, which exceeds the bounds of probability, would give 83 or 750 miles respectively. In his preface he shows that his ideas of the aurora are original, although partly the same as those of previous authors. He finds that the beams of the aurora borealis are governed by the earth's magnetism, but notes that this idea had been conjectured by Mr. George Birbeck, of Settle, Yorkshire, and that it had also been more fully expounded by Halley.
Results of Professor Eschenhagen's magnetic investigations in the Harz Mountains
Authors: Putnam G. R.
Published: February 2008

Under the auspices of two German geographical and geological societies, Professor Eschenhagen, during the years 1888 and 1890, made detailed magnetic observations at 42 stations in the Harz Mountains, which lie about 125 miles southeast of Berlin. Earlier investigators had noted the fact that the granitic rocks of this region were sometimes strongly magnetic, but had not gone beyond the local surface conditions. This work, however, was intended to develop the more general magnetic anomalies in this region, and especially their relation to the geological structure, and to the data furnished by the geodetic surveys as shown by the plumb line deflections, indicating certain conditions of the attracting masses beneath the surface. An investigation very similar to this was carried out by Fritsche in the vicinity of Moscow in 1983. The Harz region is well adapted to research of this character; for the reason that magnetic observations have been made in the surrounding portions of Germany from which the normal conditions may be deduced; and, further, because these mountains have been studied geologically, and have also been covered by geodetic triangulation, from which the plumb line deflections have been computed.
Patterns of contaminated zones of water in the ground
Authors: Legrand H. E.
Published: February 2008

Movement of contaminants from many waste sites into the subsurface water circulation system results in contaminated zones, or enclaves, in the zone of saturation (below the water table). Difficulty in predicting the areal extent of a contaminated zone stems from the multiplicity of factors that need consideration, including: the great variety of waste materials, their range in toxicity and adverse effects; man's variable pattern of waste disposal and of accidental release of contaminants in the ground; man's variable pattern of water development from wells; behavior of each contaminant in the soil, water, and rock environment; ranges in geologic and hydrologie conditions in space; and ranges in hydrologie conditions in time. Two opposing tendencies need to be in focus before an evaluation of contaminated zones is undertaken: (1) the tendency of contaminants to be entrained in groundwater flow and (2) the tendency for contaminants to be attenuated to varying degrees by dilution in water, decay with time, or some other ‘die‐away’ mechanism, and sorption on earth materials. Once a contaminated zone is approximately stable, an increase in concentration may cause it to remain about the same size under some conditions and to enlarge in others, according to combined attenuation effects. Where attenuation occurs only by dilution, the contaminated zone will become enlarged with increased concentration, and, where dilution is also slight, it may become greatly elongated in the direction of groundwater, and perhaps also of surface‐water, flow. Where attenuation occurs also through decay or sorption, or through both mechanisms, the contaminated zone may not enlarge appreciably, even if the concentration of contamination is increased. The upper part of the zone of saturation in populated parts of the Earth may be considered as a galaxy in which millions of enclaves of contaminated water are scattered in uncontaminated groundwater. Interspersed with these enclaves are millions of water‐supply wells, some of which pump contaminated water or help to disperse it even if it does not reach them. Although too few contaminated zones have been delineated to enable a statistical analysis of areal patterns, an approximation of their patterns of distribution can be deduced.
Streamflow characteristics of physiographic units in the northeast
Authors: Sopper William E. , Lull Howard W.
Published: February 2008

An analysis was made to determine the amount of annual and seasonal water yield, flow duration, and peak flow frequency for seven major physiographic units in the northeast. AU watersheds (137) in the northeast that were less than 100 square miles in area, that had continuous records from 1940 to 1957, and that were not appreciably affected by regulation and diversion were included in the analysis. In addition, streamflows of four small forested experimental watersheds were compared with average streamflow values of the physiographic units in which they were located. The longest simultaneous record available was for a 3‐year period from 1959 to 1962. Results indicate significant differences in water yield between physiographic units as well as between watersheds within units. Water yields from the small experimental watersheds, although based on a shorter and different period of time, were found to correspond closely with average water yields of their respective physiographic units.
Streamflow from small watersheds on the western slope of the Cascade Range of Oregon
Authors: Rothacher Jack
Published: February 2008

Streamflow from small watersheds on the western slopes of the Oregon Cascade Range is strongly influenced by a maritime climate (wet winters and dry summers). Although annual precipitation is high (94 inches in the study area), overland flow is almost unknown. Peak flows result largely from subsurface flow and under conditions in which both retention and detention reservoirs are almost filled during extended periods of low‐intensity rainfall. Under these conditions, vegetation appears to exert a minimum influence on high streamflow. Lowest Streamflow occurs from late August to mid‐November and may follow a 60− to 100‐day period with little or no rain. The dense vegetation of this part of the Douglas‐fir region appears to exert its major influence at such times. Removal of vegetation from only 30% of a 250‐acre watershed has caused a 12–28% increase in minimum streamflow. On a 237‐acre watershed on which 80% of the trees were cut, the increase in low flow was 85%.
Water quality management: Engineering‐economic factors in municipal waste disposal
Authors: Frankel Richard J.
Published: February 2008

Savings in treatment costs to municipal water treatment plants downstream result directly from improved municipal sewage treatment upstream. The maximum return per additional investment dollar is from primary to secondary sewage treatment. The ratio of cost savings to the costs of additional treatment varies between negligible and 0.10. The quantity of withdrawal for municipal water supply required to justify additional upstream treatment costs is of the order of from 16 to 250:1 for small sewage treatment plants and from 10 to 30:1 for large sewage treatment plants, if in‐place use and stream quality are of minor importance. If clean streams are desired, the costs of maintaining high stream quality must therefore be justified by in‐place uses, such as for recreation and fish and wildlife preserves. In areas where reclamation of municipal waste effluents is feasible, present emphasis on maximizing stream assimilative capacity through minimum waste treatment is poor utilization of water resources.
The demand for inland waterway transportation
Authors: Silberberg Eugene
Published: February 2008

A new type of forecasting model of great potential for predicting flows in complicated spatial transportation networks is illustrated through application to the forecasting of interregional coal flows by barge over the Mississippi River system. Changes in these flows are related to regional coal production and consumption levels and to the freight charges by barge and rail. The special feature of the model is the great saving on the data needed for its implementation made possible by assuming that transportation patterns will be efficient, i.e., least‐cost, for given regional imports and exports. This assumption is incorporated by using the linear programming transportation method to generate individual flows from regional barge imports and exports forecasts by a system of statistically fitted equations. Various applications are illustrated.
A conceptual model of stomatal control mechanisms
Authors: Woo K. B. , Stone L. N. , Boersma L.
Published: February 2008

The stomata of plant leaves constitute a main regulating system of the transpiration process. Biologists have suggested a turgor mechanism to explain stomatal movement. The functions of the mechanism are quantitatively described by an osmotic water transfer theory and/or the active water transfer theory in the guard cells. Based on the active water transfer theory and the observations of stomatal movement under various conditions of H2O, CO2, and light, a conceptual model of the stomatal control mechanism is proposed. Transfer functions of the mechanisms characterizing the changes in turgor pressure have been derived. The entire system has been organized by the application of adaptive control system theory and has been simulated on an analog computer. The dynamic characteristics have been investigated with consideration of various environmental conditions. (Key words: Computers, analog; plants; soil moisture.)
Theoretical prediction of evaporation losses from groundwater
Authors: Liakopoulos Aristides C.
Published: February 2008

The transient values of water pressure, water content, and rate of water evaporation from soils can be predicted theoretically from the mathematical model representing the physical problem of the evaporation phenomenon from soils. Evaporation of water from a soil surface is an initial‐value problem arising in many cases of water transfer through soils. A nonsteady state exists that leads to the mathematical model of a nonlinear parabolic partial differential equation in which the time and the position in the vertical direction are taken as the independent variables and the volumetric water content as the dependent variable. Because of the strong nonlinearity, the governing partial differential equation is approximated by finite differences at discrete mesh points in the solution domain and is integrated for initial and boundary conditions corresponding to the evaporation phenomenon. The procedure for the numerous calculations required for the numerical integration is programmed in Fortran coding language, and fast answers consisting of transient values for the pressure distribution, water content, and evaporation rate are obtained with the aid of an electronic digital computer IBM 704. (Key words: Evaporation; porous mediums; soil moisture; unsaturated flow.)
Radar measurements for the assessment of areal rainfall: Review and outlook
Authors: Kessler Edwin
Published: February 2008

Radar applications for measurement of areal precipitation are reviewed. Radars with a beam width of 2° or less and a wavelength of 10 cm should provide improved measurements of areal rainfall and more timely and comprehensive rainfall reports. However, substantial realization of radar's potential in operational hydrology requires further examination of the correspondence between radar and rain gage data, refinement of communicating and computer‐processing techniques for radar data, and development of means for measuring precipitation echoes in the presence of terrain echoes. (Key words: Rainfall; instruments, radar)
Water loss from a natural pond through transpiration by hydrophytes
Authors: Eisenlohr W. S.
Published: February 2008

The water loss to the air from a natural pond in which hydrophytes are growing consists of two parts, evaporation and transpiration. As both parts vary directly with the same meteorologic factors, the total loss, evapotranspiration, can be computed by means of a simplified mass transfer equation in which the only coefficient has been evaluated for that pond by means of a water budget. In addition to the variation with meteorologie factors, transpiration occurs at different rates throughout the growing season, depending on the stage of growth. Evaporation is affected by the amount of vegetation present. The mass transfer coefficient varies in accordance with these conditions. By assuming that the coefficient during the dormant season represents losses by evaporation alone, a basis is obtained for estimating the coefficient representing evaporation during the growing season. The computed evapotranspiration minus the computed evaporation gives the water loss attributed to transpiration alone. (Key words: Hydrophytes; evapotranspiration; lakes; North Dakota)
Theory of rainfall uptake by soils initially drier than their field capacity and its applications
Authors: Rubin Jacob
Published: February 2008

The Darcian approach to moisture transfer in unsaturated soils yields a flow equation that was utilized for formulating a theory of rainfall infiltration. Analytical considerations applied to this equation yield a qualitative description of the infiltration process, as well as the necessary and sufficient conditions for the occurrence of ponding and the absence of soil‐parameter hysteresis. Numerical solutions of the flow equation, obtained by means of finite‐difference methods, furnish quantitative information on the moisture profiles and infiltration rates during nonponding, preponding, and ponded‐rainfall infiltrations. The theory is not utilizable when the soil exhibits significant air compression, parameter hysteresis,fabric transformations, or areal heterogeneity. For soils with known moisture parameters and rains of a given intensity‐pattern, the theory, whenever applicable, can furnish information useful in dealing with problems of runoff control or sprinkler irrigation, e.g., estimates of excess rainfall rates and of water uptakes at incipient ponding.
The effect of natural rainfall variability in verification of rain modification experiments
Authors: Huff F. A.
Published: February 2008

Data from four concentrated rain gage networks in Illinois were used to investigate the effect of natural rainfall variability upon verification of cloud seeding experiments in midwestern, warm season rainfall on areas of county size or less. Hypothetical seeding experiments were made on network data for seasonal periods of 1 to 5 months and or durations of 1 to 10 years. Both target‐control and single‐area randomized experiments were investigated, and the data were grouped into air mass storms and all storms combined. Results indicated that the single‐area sampling experiments are influenced more by the effects of natural rainfall variability than the target control type, but that the background interference is substantial in both cases. The study clearly illustrates the pitfalls in judging the results of cloud seeding on short‐term experiments, and shows how verification may be affected by rain gage density and size of sampling area.
Average probability of extreme events
Authors: Benson Manuel A.
Published: February 2008

During the course of a study of flood insurance and insurance rates, it was found necessary to take into account the risk, over a long period of time, from all floods above the 100‐year flood level. The problem was approached by considering first what is the average probability of all floods above the 100‐year level. It was found that the average probability of all such floods is equal to 0.005, or the probability of the 200‐year flood. In general, it could be shown that the average probability of all floods above the k‐year flood is equal to l/2k.
Drawdown in a well of large diameter
Authors: Papadopulos Istavros S. , Cooper Hilton H.
Published: February 2008

A solution for the drawdown in a large‐diameter well discharging at a constant rate from a homogeneous isotropic artesian aquifer, which also takes into consideration the water derived from storage within the well, is presented. A set of type curves computed from this solution permits a determination of the transmissibility of the aquifer by analysis of drawdown observed in the pumped well.
The effect of applied interception on transpiration rates of potted Ponderosa pine
Authors: Thorud David B.
Published: February 2008

Water was artificially applied to the foliage of small potted ponderosa pine trees to determine the effect of wetting on transpiration rates. By means of unwetted control trees and a prediction equation, the transpiration of wetted trees could be estimated had they not been wetted. The difference between the estimated and actual transpiration was a measure of the transpiration reduction due to treatment. For thirty‐six 2‐hour periods the average transpiration reduction was 14%, or 9% of the applied water. Thus, about 91% of the applied water was a net loss to soil moisture supplies. The saving as a per cent of applied water varied from 4 to 14 and appeared to be weather related. Minimum values were generally observed on both cool, humid days and dry, hot, windy days. Higher savings were observed with more moderate weather. (Key words: Transpiration; interception; soil moisture)
Hydraulic and micromorphological properties of stream channel sediments
Authors: Qashu H. K. , Buol S. W.
Published: February 2008

In the arid and semiarid regions of the southwestern United States, a large portion of the natural water recharge is through channel beds and alluvial deposits in river basins. Water transmission in these beds varies with time, location, depth and extent of alluvium, and hydraulic characteristics of flows, sediment loads, and morphology of the channels. An alluvial profile in an ephemeral stream channel was found to have layers with relatively high clay and silt accumulation. Samples from a pit in the channel were subjected to a micromorphological examination using thin sections. Clay and silt were found to have accumulated on sand and gravel particles and around aggregates. In the laboratory, samples of alluvium material were dispersed. The clay and silt fractions were collected, dried, and then mixed again with the washed material. The hydraulic conductivity of the mixed material was 30% less than that for the nondispersed sample. These results are attributed to the orderly arrangement of clay and silt on the surfaces and between the larger sand and gravel particles of the nondispersed samples. (Key words: Sediment; porous medium; infiltration; permeability)
The determination of the lonization constant of 2,4‐D in water
Authors: Wershaw R. L. , Goldberg M. C. , Pinckney D. J.
Published: February 2008

The compound 2,4‐D (2,4‐dichlorophenoxyacetic acid) is the most widely used herbicide in the United States, and its widespread use may result in the applied compounds being carried or washed into nearby water courses, rivers, lakes, or groundwater reservoirs. This situation has stimulated basic studies on the chemical and physical behavior of 2,4‐D in water. Studies by various authors show that 2,4‐D degrades within several weeks in soils; it can persist for up to six months or more in natural waters. The ionization constant of 2,4‐D has been redetermined at 25°C from conductivity measurements. A value for the ionization constant of 1.169 × 10−3 was calculated when the equivalent conductance at infinite dilution of 2,4‐D was computed from the equivalent conductance at infinite dilution of the sodium salt of 2,4‐D, using the Kohlraush method of independent ion mobilities. These results differ from those obtained by other workers, who have computed the equivalent conductance at infinite dilution of 2,4‐D, using the equations derived by Fuoss and his co‐workers for the conductance of strong electrolytes in polar solvents. (Key words: Geochemistry; pollution; quality of water)
Groundwater management under quadratic criterion functions
Authors: Burt Oscar R.
Published: February 2008

Temporal allocation of groundwater is analyzed for quadratic measures of economic net output from a basin. The two variables of the net output function are rate of use and quantity of stocks. It is shown that an optimal policy for groundwater utilization over time is dependent upon the mean recharge rate but not on higher moments of its probability distribution for the case of quadratic criterion functions, provided that inequality constraints on rate of use are unnecessary. The optimal policy is derived, and some analysis of the probability distribution of groundwater stocks is made. Some consideration is given to approximately optimal policies for the situation arising when inequality constraints on rate of use are binding.
The hydrologic importance of transpiration control by stomata
Authors: Lee Richard
Published: February 2008

Plant canopies are not passive evaporating surfaces. The regulation of water loss from plants is an important function of leaf stomata, and significant stomatal regulation occurs throughout the range of leaf‐pore diameters. Leaf pores do not ‘interfere’ with one another to any significant extent in the conductance of water vapor or other gases. The diffusive conductance of small pores is more sensitive to diameter changes at the larger apertures, thus permitting CO2 exchange for photosynthesis without dehydration of the leaf mesophyll. In still air the external resistance over broad leaves limits control by stomata, but light drafts usually minimize this effect in field situations. Characteristic diffusion coefficients for leaf types, based on a careful study of leaf microstructure, physiology, and seasonal variation, are a rational basis for cover‐type conversions or biochemical controls to reduce water loss.
Simulation of a National Flood Insurance Fund
Authors: Schaake John C. , Fiering Myron B
Published: February 2008

A model for simulating a national flood insurance fund is formulated. The objective is to model the fund and to specify optimal or near‐optimal values of the premium rates, discount coefficients, initial capitalized value, and the reinsurance structure. The simulation model synthesizes flow traces, maps these into damages, collects premiums, indemnifies losses, collects reinsurance premiums from the insurance industry, and indemnifies that industry's excess losses. Relevant statistics that describe the behavior of the fund are accumulated. The mean and variance of simulated annual flood damages for the United States agree well with results of other studies. The agreement is particularly good in view of the paucity of systematically collected flood data in urban areas. Exponential growth in the variance of the fund over time was observed. This growth can be controlled by managing the fund.
Soil water translocation in a high water table area
Authors: Benz L. C. , Willis W. O. , Sandoval F. M. , Mickelson R. H.
Published: February 2008

A field experiment was conducted to evaluate soil water, water table, and soil temperature relations in an area having a high water table, saline soil, and artesian water. The water table during winter lowered owing to upward migration of ground water toward the colder surface soil. However, the water content of the 2.7‐meter soil profile increased in an amount of water exceeding that accountable by the drop in the water table, precipitation, and horizontal flow. The additional water was most likely contributed from the artesian aquifer underlying the area.
A field study of the effectiveness of fatty alcohol mixtures as evaporation reducing monomolecular films
Authors: Bean B. R. , Florey Q. L.
Published: February 2008

A field study of the effectiveness of fatty alcohol mixtures as evaporation reducing monomolecular films was carried out at Lake Hefner, Oklahoma. Evaporation, as determined by the eddy flux method, was reduced, on the average, by 58%.
United States tritium rainout and its hydrologie implications
Authors: Stewart G. L. , Farnsworth R. K.
Published: February 2008

Tritium concentrations of precipitation, total rainout, and rainfall amounts for 1964 and 1965 are listed for 15 stations in the conterminous United States, Alaska, and Puerto Rico. These data show that the major increase in tritium rainout observed in 1963 was followed by a decline of about 27% in 1964 compared with 1963, and an additional decline of about 54% in 1965 compared with 1964. Rainout patterns are characterized by increases in tritium rainout with northern latitudes and with distance from the oceans. The total tritium rainout, being a function of both concentration and amount of precipitation, is more random than average tritium concentration. Seasonal, annual, and even ten‐year tritium pulses have provided a valuable tag for tracing water in many kinds of hydrological and meteorological investigations. The tritium data now available make it possible to estimate the tritium input to the hydrologic environment at any part of the United States.
Reservoir Management: The Tradeoff between Low Flow Regulation and Flood Control
Authors: Young G. K.
Published: February 2008

Existing flood control reservoirs should be considered for use to increase flow in dry periods to accommodate water quality. This issue is discussed, and a simplified case study is presented. The objective is to find operation schemes that minimize expected losses, which are specified such that low flow penalties are considered along with flood losses. Solutions for the example are given that indicate the degree to which flood and water quality control are complementary.
A Versatile, Gas‐Operated Water‐Level Recorder
Authors: Helmers A. E.
Published: February 2008

A water‐level recorder that operates by sensing pressure as gas is bubbled freely, through depths of water has been used for recording water levels in piezometers and storage precipitation gages. This instrument appears adaptable to recording stream stage and ground water levels and to other uses. Parts and materials cost less than $200.
Water Temperatures in a Shallow Lake During Ice Formation, Growth, and Decay
Authors: Bilello Michael A.
Published: February 2008

Continuous water‐temperature measurements were made in a shallow lake in upper Michigan during ice formation, growth, and decay. Just before complete freeze‐over, the temperature of the water from just below the surface to the bottom of the lake reached a minimum of +0.2°C. After a permanent ice cover had formed, the water beneath the ice began to warm up. During a 25‐day period in December, the water temperature near the bottom of the lake increased from +0.3°C to +3.0°C. A quantitative analysis of this heat gain attempts to show that most of it came from the energy stored during the summer in the underlying soils. During the ice‐thaw period in April, the temperature throughout the main mass of water decreased substantially. Since the lake until this time was in a state of quasi‐stable thermal stratification, it was assumed that this cooling resulted from the mixing of meltwater flowing into the lake from surrounding snow.
Laboratory Evaluation of Selected Radioisotopes as Ground‐Water Tracers
Authors: Jennings A. Ray , Schroeder Melvin C.
Published: February 2008

As the appearance of a tracer results from movement along the most direct flow path, the arrival of the maximum concentration is the best index for determining the average water velocity. Antimony 121, cerium 141, chromium 51, indium 114, ruthenium 103, and strontium 85 in chelate form were tested, as the unchelated ions are subject to greater delay by adsorption and ion exchange. Distribution‐coefficient measurements were made under static conditions for crushed illitic shale and limestone. These measurements can be used to predict the elution history of a tracer from an exchange column. Comparisons of the predictions, the tracer elution histories, and elution histories for chloride pulses indicate that chelated chromium 51 is an adequate ground‐water tracer. The average velocity of ground water is equal to the sum of the tracer velocity plus the product of the tracer velocity, the distribution coefficient, and the bulk density of the aquifer divided by its effective porosity. The distribution coefficient for an ideal tracer is zero, and the average velocity of this tracer is equal to the average ground‐water velocity.
Steady Infiltration From Buried Point Sources and Spherical Cavities
Authors: Philip J. R.
Published: February 2008

Steady infiltration in two‐ and three‐dimensional systems has been treated classically as a process of saturated flow with a free surface. The series this paper initiates deals with the generally unsaturated flow regimes set up by prolonged infiltration into regions with no shallow ambient water table. The analysis is simpler than the classical one in the sense that it does not involve a free surface. With hydraulic conductivity represented by an exponential function of moisture potential, the nonlinear equation for steady flow is transformed into a linear equation which is formally equivalent to that for diffusion in a moving medium. The fundamental point source solution is explored and is used as the basis of an analysis of steady infiltration from spherical cavities. For cavities of small (dimensionless) radius, the infiltration rate is determined almost wholly by capillarity; on the other hand, gravity distorts the pattern of moisture distribution strongly, even when the cavity radius is small.
Seepage Through an Earth Dam Computed by the Relaxation Technique
Authors: Finnemore E. John , Perry Byrne
Published: February 2008

The problem of seepage flow through a homogeneous earth dam is investigated on the assumption that the flow is plane, steady, and governed by Darcy's law. In this case the governing equation for the pressure head is the Laplace equation, and the boundary conditions are straightforward except at the phreatic surface, which is a free streamline with location initially unknown. The problem is solved by adapting the relaxation method for machine computation. In particular, the intuition of the hand calculator is replaced by automatic procedures more suited for the machine. Closely agreeing solutions were obtained for separate executions having widely different initial (guessed) positions of the free streamline. These solutions, execution of each of which took from 50 to 70 seconds on an IBM 7090, are in excellent agreement with the longhand solutions of Shaw and Southwell. Computer flow rates agreed very well with the theoretical discharge given by the Dupuit formula.
A New Method of Flow Routing
Authors: Himmelblau D. M. , Yates R. V.
Published: February 2008

A population balance model to predict the excess flow above the normal channel flow involves four coefficients that can be evaluated at a downstream point from pulse impulses of water upstream. Furthermore, the parameters can be directly related to the general characteristics of the stream in terms of hold up, bypassing, and dead space. The model itself comprises two parallel series of well‐mixed vessels without interchange of water and can be modified to make the model more complex. Application of the model to data from the Colorado River in Texas indicates that the model satisfactorily represents the excess flow for pulselike stream releases. (Key words: Forecasting; hydrology; streamflow)
Field Observations on Changes in the Subsurface Water Regime During Influent Seepage in the Santa Cruz River
Authors: Wilson L. G. , De Cook K. J.
Published: February 2008

Field studies were conducted during the winter 1965–1966 at an instrumented research site near Tucson, Arizona, to characterize changes in the subsurface water regime of the stratified sediments at the site during influent seepage in the Santa Cruz River. At the peak of recharge from the principal runoff event of the winter, observation well data accounted for 33% of the observed total change in the subsurface water content. The remaining 67%, observed by means of moisture logs in access tubes, was contained in two near‐saturated mounds in the intermediate vadose zone. Slow drainage of water from these mounds into the semiconfined phreatic zone apparently reduced the rates of recession of observation well hydrographs. Water content changes in the intermediate vadose zone and related long‐term drainage should be accounted for during water balance studies and aquifer testing in the Tucson Basin. (Key words: Arizona; river seepage; ground water)
The Measurement of Low Fluid Velocities with the Aid of a Tethered Sphere
Authors: Stefan Heinz , Schiebe Frank R.
Published: February 2008

Two‐ or three‐dimensional velocity fields in hydraulic models can be measured with the aid of a tethered sphere if the absolute velocity values are very small. The apparatus is relatively simple and quite sensitive. Experimental data can be handled numerically, taking into account all effects, and print‐out is readily available in useful tabular or graphical form. The greatest disadvantage at present seems to be that the position of the tethered sphere is not stable, and it is difficult to define when turbulence is present in the flow. The average position of the sphere will most probably not correspond to the velocity average in this case. This disadvantage is, however, shared by most velocity measuring devices with low frequency response. The second inaccuracy is that the program presently available is based on the assumption that the velocity is uniform over the height of the probe. The development of a new program taking into account continuously varying velocity and temperature profiles is in progress. It is of particular importance for small spheres on long support lines. The instrument may also be inverted by using a sphere slightly heavier than water. Such an instrument would be suitable for velocity measurements near the bottom of a channel. (Key words: Data; density currents; instruments; low velocity)
Water Pollution Control Using By‐Pass Piping
Authors: Graves G. W. , Hatfield G. B. , Whinston A.
Published: February 2008

This paper presents a mathematical model of regional water quality management using by‐pass piping. The model is developed within the framework of linear programming and a large‐scale problem is solved using semi‐realistic data from the Delaware Estuary. The technique of generation of elements is used in conjunction with the truncated tableau to provide efficient solutions. A possible method of taxation is indicated based on the values of the dual variables.
Runoff Hydrograph as a Function of Rainfall Excess
Authors: Hill I. K.
Published: February 2008

A set of differential equations has been obtained for the overland runoff from an arbitrary catchment when the rainfall excess over the catchment is known as a function of space and time. An analytical solution is given for a steady rain of finite duration. The differential equations obtained are also solved analytically for a moving top‐hat storm over a plane catchment, and the maximum depth is obtained explicitly as a function of the storm duration and catchment length. The results for all plane catchments with a given resistance formula are reduced to a single curve. It is found that the depth is increased if the storm moves downstream and decreased if the storm moves upstream, the slower the storm the greater being the change. If the storm period exceeds a critical value, with a storm moving downstream, then the depth is increased by a factor n1/n−1 for a sufficiently long catchment. The parameter n is the exponent of depth in the discharge depth relation. Finally, it is shown that all the results apply qualitatively to open channel flow where the kinematic wave approach is suitable. If the lateral inflow replaces the rainfall excess, it is found that the form of the curve describing the variation of depth with time is a function of the cross‐section geometry but is qualitatively similar to the overland flow curve described above.
Linear time‐varying model of rainfall‐runoff relation
Authors: Chiu Chao‐Lin , Bittler Ronald P.
Published: February 2008

The linear time‐varying system model of the rainfall‐runoff relation can be represented by a first‐order, linear differential equation with time‐varying coefficients that depend on two parameters. The model does not require the time‐variance assumption necessary in the conventional unit hydrograph method. The long‐ and short‐term trends for a hydrologic system to change with time can be considered and described with the technique developed. Analysis of historical data for the rainfall‐runoff relation of a basin used for an experimental study indicates that the response of the basin to rainfall significantly changes with months during a year, although the yearly variation is not significant. The developed model and techniques used in the experimental study to describe and predict the rainfall‐runoff relation have proved satisfactory.
The improvement of water quality under a financial constraint: A commentary on ‘linear programming applied to water quality management’
Authors: Revelle Charles , Dietrich Gary , Stensel David
Published: February 2008

Limited funds for building treatment facilities on a river basin are allocated to secure the largest possible value of the minimum level of dissolved oxygen. Linear programming is utilized to determine the configuration of efficiencies that achieve this goal. At optimality, the dual variable associated with the financial constraint indicates the instantaneous rate of change of the minimum dissolved oxygen concentration with respect to the funds available. Several alternative formulations of the problem are discussed. A numerical example is solved to illustrate the methodology.
Optimization of a Class of River Aeration Problems by the Use of Multivariable Distributed Parameter Control Theory
Authors: Tarassov Victor J. , Perlis Harlan J. , Davidson Burton
Published: February 2008

Multivariable distributed parameter control theory has been applied to the optimization of artificial in‐stream aeration of polluted rivers. The optimization was developed for a general integral type of cost functional with weighted energy constraints. Three specific types of aeration control policies were considered: distributed space and time control, distributed time control, and distributed space control. Employing typical hydrologic coefficients with the transient version of Streeter‐Phelps equation, the optimal aeration control surfaces obtained were all found to lie well within the operating characteristics of commercial aeration equipment. Distributed parameter control theory applied to water pollution systems proved to be a powerful mathematical programing method comparable to linear and dynamic programing.
Plant Nutrients in Base Flow of Streams in Southwestern Wisconsin
Authors: Minshall Neal , Nichols M. Starr , Witzel S. A.
Published: February 2008

The study covers a two year period in order to determine the plant nutrients in the base flow of southwestern Wisconsin streams. The average base flow from 36 drainage areas covering a total of 643 square miles was 0.360 cu ft/sec sq mi, representing 4.9 in/yr. The annual nutrient losses in base flow were nitrogen, 1.1 lbs/acre; phosphorus, 0.10 lb/acre; and potassium, 1.8 lbs/acre. These losses were only one fourth of those in the 1967 surface runoff from 0.01‐acre plots at the Lancaster Experimental Farm and three Agricultural Research Service watersheds near Fennimore, Wisconsin.
A Simple Snowmelt Lysimeter
Authors: Haupt Harold F.
Published: February 2008

A simple gage on the lysimeter principle has been developed to provide continuous readings of the volume of water flowing from the base of a snowpack in the form of surface melt alone or rain percolate and surface melt combined. The data obtained show promise, after two seasons, of being applicable in river flood forecasting, as well as in studies of snow hydrology.
Snow Accumulation on Mount Logan, Yukon Territory, Canada
Authors: Keeler C. M.
Published: February 2008

Measurement of snow accumulation for the year from summer 1967 to summer 1968 on Mt. Logan, St. Elias Mountains, Yukon Territory, Canada, indicates that annual precipitation is approximately 0.65 meters yr−1 for elevations between 3350 and 5400 meters. This is less by a factor of 5 than annual precipitation at sea level on the Gulf of Alaska. On a regional basis precipitation decreases inland from the Pacific Ocean at a rate of approximately 2 × 10−5 meters km−1. Precipitation decreases on the windward and increases on the leeward sides of the St. Elias Mountains with respect to elevation.
Generation of an Evaporation Time Series for Lake Ontario
Authors: Yu Shaw Lei , Brutsaert Wilfried
Published: February 2008

Monthly mean values of evaporation from Lake Ontario for the period from 1872 to 1965 inclusive were generated by a mass transfer procedure. Available onshore recorded meteorologic data were adjusted to obtain approximate over lake values with empirically derived equations. The mass transfer coefficient was calculated by using an equation proposed by Harbeck [1962] relating the coefficient with water surface area. A comparison of the generated mass transfer evaporation data with water budget estimates obtained by Morton [1967] revealed that on the average the two methods gave similar results.
Numeric Studies of a Composite Soil Moisture Ground‐Water System
Authors: Hornberger G. M. , Remson Irwin , Fungaroli A. A.
Published: February 2008

A model of transient moisture movement in a composite soil moisture ground‐water system is described. The model was used to study two‐dimensional flow in response to a falling water table. The solution provided information about the interaction of the saturated and unsaturated portions of the subsurface system.

The results of the composite model are compared with those obtained from three one‐dimensional ground‐water models. That soil moisture and nonlinearity do not have a significant effect on the position of the water table in the system studied is inferred.
Evaluation of benefits of a flood warning system
Authors: Day H. J. , Bugliarello G. , Ho P. H. P. , Houghton V. T.
Published: February 2008

Benefits due to a flood warning system are estimated by using individual structure stage damage curves for several warning periods. Typical stage damage warning time data for residences, a grocery Supermarket, and a railroad switchyard serve as examples for benefit evaluation. The application of these concepts to 650 residences involved in the 1959 flood at Meadville, Pennsylvania, indicated that reducible damages represent approximately one third of the total residential damage. Both evacuation and temporary floodproofing, two non‐structural alternatives used frequently, may be evaluated more explicitly by this method.
Storage yield: Extending the Sequent Peak Algorithm to multiple reservoirs
Authors: Young G. K. , Puentes C. D
Published: February 2008

The sequent peak algorithm is extended to find volume requirements as a function of time. These requirements are helpful in determining reservoir construction timing in multiple reservoir systems. The principal variable used in the algorithm characterizes a reservoir storage history which is unfounded by volume limits.
Net radiation in a riparian mesquite community
Authors: Tromble J. M. , Simanton J. R.
Published: February 2008

Net radiation patterns for a riparian mesquite community are similar to net radiation patterns obtained for a humid forest. The net radiation peak of the open area was 61% of the net radiation peak above the canopy. The net radiation within a mesquite canopy peaked 9% higher but had a lower daily total value than the radiation above the canopy. The differences in net radiation peaks were attributed to differences in the canopy geometry, solar position, and surface reflectance, whereas differences in daily net radiation were attributed to differences in surface reflectance characteristics.
An Alternate Procedure for the Optimization of Operations for Planning with Multiple River, Multiple Purpose Systems
Authors: Hall Warren A. , Tauxe G. W. , Yeh W. W‐G.
Published: February 2008

A technique is developed for maximizing the financial feasibility of a complex, multiple river water resources system for planning purposes, based on deliveries of firm power, in‐season water, dump power, and off‐season water, with flood control and releases for noncommensurate objectives as parameters.

This method is an important modification of a previously reported analysis involving dynamic programing, linear programing, and modified gradient procedure, replacing the computationally inefficient linear programing determination of the shadow prices by a standard sequence of constraints. Total computation time is reduced from hours to minutes.
On the Extreme Value Distribution for Describing Annual Flood Series
Authors: Huxham S. H. , McGilchrist C. A.
Published: February 2008

Some criticisms concerning the use of the extreme value distribution for annual flood series are considered. The extreme value distribution can now be fitted easily and efficiently to extreme data. Although the theoretical extreme value distribution is only an asymptotic result, for moderate sample sizes an extreme value distribution with parameters different from the theoretical ones is often a good fit to the data.
Estimation of Statistical Parameters for Annual River Flows
Authors: Rodríguez‐Iturbe Ignacio
Published: February 2008

A first order Markov process is chosen as representative for annual river flows. The normalized standard errors of the estimates of the mean, the variance, and the first autocorrelation coefficient are shown as functions of the sample size for a river which is considered to have average statistical characteristics. The theoretical analysis is complemented with a study of the variations with sample size of the main statistical parameters of three rivers with a large amount of data. The results show that on the average between 40 and 60 years of data are desirable to estimate the mean and the variance. The normalized standard error grows rapidly with any diminishing of the sample size. Beyond this range the normalized standard error of estimate decreases slowly with lengthening sample size. Large errors appear to be common in estimating the first autocorrelation coefficient, even for series whose length is much longer than is normally found.