bluuebunny/crossref_metadata_2025 huggingface dataset:
Steady Infiltration from a Shallow Circular Pond
Authors: Wooding R. A.
Published: February 2008

Steady infiltration from a shallow, circular, inundated area on the horizontal surface of a semi‐infinite porous medium is treated by a method of linearization proposed by J. R. Philip. Using this method, Philip retains most of the properties of the nonlinear system but reduces the differential equation to a linear type governing steady diffusion in a steady uniform flow. On the surface of the medium, the boundary conditions are of mixed type, although linear. These conditions are reduced to a system of dual integral equations solved by a modification of Tranter's method. Expressions for the distributions of vertical flux density, moisture content, and Stokes' stream function are derived, and numerical values of the last two quantities are illustrated graphically. It is found that the total flux depends almost linearly upon a parameter α, defined as the logarithmic derivative of the hydraulic conductivity with respect to capillary potential. Curves of mean flux over various radii (fractions of the total source radius) for various values of α indicate the importance of the guard ring in infiltrometer design.
Determining the Ratio of Horizontal to Vertical Permeability by Aquifer‐Test Analysis
Authors: Weeks Edwin P.
Published: February 2008

The ratio of horizontal to vertical permeability may be determined by analysis of drawdown data from piezometers or partially penetrating observation wells near a partially penetrating production well. The analyses are made by comparing measured drawdowns in the piezometers to those predicted if the production well fully penetrated the aquifer. The differences between the measured and predicted drawdowns are determined, and the distances from the pumped well at which these differences would occur in an isotropic aquifer are determined from an equation. The permeability ratio is computed as the square of the ratio of actual distances to computed distances. The ratio of horizontal to vertical permeability in glacial outwash in central Wisconsin was determined from 5 aquifer tests to range from about 2 to about 20.
In Defense of Experimental Watersheds
Authors: Hewlett John D. , Lull Howard W. , Reinhart Kenneth G.
Published: February 2008

Recent criticisms discount the contribution of experimental watersheds to the science of hydrology and to watershed management. The critics cite as disadvantages the cost of experimental watersheds, their unrepresentativeness, leakiness, difficulty in applying results to other areas, and the lack of progress in basic knowledge about hydrologie processes. Some critics propose mathematical synthesis, statistical analysis, plot studies, soil moisture studies, meteorological methods, and the study of individual hydrologie processes as alternatives to experimental watersheds. The criticisms lack weight, because published results of catchment experiments were not carefully reviewed. The alternatives are obviously aids rather than substitutes for experiments on watersheds. By reference to recent and older results, the authors argue that the experimental watershed method has produced much of our present knowledge about the land phase of the hydrologie cycle and man's influence on it, that the method is sound, and that its future in any comprehensive research program is secure.
The effect of bends on dispersion in streams
Authors: Fischer Hugo B.
Published: February 2008

Bends in streams induce secondary currents that alter the rates of both transverse mixing and longitudinal dispersion. Within a bend the transverse mixing coefficient depends on the square of the mean velocity, cube of the depth, and inversely on the shear velocity and square of the radius of curvature, as verified by a laboratory experiment. The longitudinal dispersion coefficient depends on the channel geometry, velocity distribution, rate of transverse mixing, and a dimensionless parameter that includes the mean velocity and length of an average bend. A numerical program for predicting dispersion coefficients in streams differs from previous theories by including the effect of the alternating direction of curvature in a series of bends; the difference is important for wide streams but not for narrow ones. Experimental findings in two streams, the Green‐Duwamish in Washington (width 20 meters), and the Missouri near Omaha, Nebraska (width 180 meters), verify the numerical program.
A coring device for unconsolidated lake sediments
Authors: Schneider Robert F.
Published: February 2008

A piston‐type coring device for unconsolidated bottom deposits is described. The apparatus is a modification of the lightweight Livingstone corer. The coring tube is clear plastic, allowing visual examination of the core before extrusion, and the piston contains a vacuum release tube to prevent expansion of the cored material during removal of the piston. It is easily constructed, requiring no special machining, and is therefore relatively inexpensive compared with other similar coring devices.
Soil Slips Related to Vegetation, Topography, and Soil in Southern California
Authors: Rice R. M. , Crobett E. S. , Bailey R. G.
Published: February 2008

Soil slippage, a form of shallow mass soil movement, was studied on the San Dimas Experimental Forest in southern California after several large storms in 1965 and 1966. The three‐part study consisted of analyzing topographic data from 200 random points measured photogrammetrically; measuring soil texture, soil depth, wettability of surface soil, and hydraulic conductivity of slip surface on slipped and stable sites; and mapping and analyzing soil slips to assess the effects of watershed variables. All slips occurred on slopes greater than 80%. The ocurrence of slips was inversely related to the size and density of vegetation. In brush areas, northerly aspects were more stable than southerly ones. Conversion from brush to grass on the experimental forest may have resulted in an additional 135 m3/ha of soil slip erosion during the winter of 1965–1966.
On the Random Occurrence of Major Floods
Authors: Kirby William
Published: February 2008

Plausible hydrologic arguments imply that floods can be represented as the successes or exceedances in a sequence of randomly spaced Bernoulli trials representing the occurrence of hydrograph peaks. This representation generalizes existing flood occurrence models by admitting an arbitrary probability distribution of the times between trials and an arbitrary criterion for distinguishing between floods and ordinary hydrograph peaks. Analysis of this model shows that at sufficiently small exceedance probabilities the probability distributions and moments of the interexceedance time, the waiting time to the next exceedance, and the number of exceedances approach those implied by the occurrence of trials in a Poisson process. This theory therefore constitutes a rational justification of Poisson models of flood occurrence as well as a rational explanation of empiric observations.
A Method of Analyzing Transient Fluid Flow in Multilayered Aquifers
Authors: Javandel Iraj , Witherspoon Paul A.
Published: February 2008

A new approach to transient fluid flow in multilayered aquifers has been developed using the finite element method. This is a numeric technique in which an initial boundary value problem is converted to a variational problem and applied to a descretized system of elements. Details for the case of isotropic systems have been presented elsewhere. This paper extends the treatment to anisotropic systems. The method has been used to investigate potential distributions in multilayered aquifers of finite radial extent being pumped at constant rate using completely penetrating wells. An analysis of two‐layer systems with permeability contrasts of up to 100:1 indicates that at early time the drawdown behavior can vary significantly from the Theis solution, depending on where observations are made. As time increases, however, the results eventually converge on the Theis solution regardless of the permeability contrast. A 13‐layer aquifer containing either isotropic or anisotropic layers has been examined, and the results are in general agreement with the behavior for two‐layer systems.
The opportunity cost of displaced private spending and the social discount rate
Authors: Haveman Robert H.
Published: February 2008

The three purposes of this paper are: (1) to describe the major schools of thought regarding the meaning and calculation of the appropriate social discount rate, (2) to specify and defend a preferred opportunity cost approach, and (3) to present an empiric estimate of the appropriate discount rate under conditions prevailing in 1966. This rate was found to be 7.3% for 1966.
Marginal Values of Dilution Waters
Authors: Merritt Lavere B. , Mar Brian W.
Published: February 2008

The marginal value of water for dilution of waste is observed to be small when computed on either a long run or a short run basis. A policy of clean water places a low marginal value on dilution water since these values increase in many situations with any increase in allowable concentration of waste in the receiving water. The marginal value of waters used to dilute saline irrigation return flows is generally higher than those used to dilute oxygen demanding wastes because of the relative currently higher salt removal treatment costs and the much higher allowable receiving water concentration for most salts.
Determining Specific Yield of the Ogallala Aquifer by the Neutron Method
Authors: Jones Ordie R. , Schneider Arland D.
Published: February 2008

The specific yield of the Ogallala formation, a water table aquifer, was determined with a neutron moisture meter. An access tube penetrated a 12‐foot section of the aquifer. This section was saturated by recharging water to the aquifer and then dewatered by pumping for 11 days. The specific yield of the aquifer was calculated from neutron moisture measurements made at saturation after most gravity drainage had occurred. The average specific yield for 25 measurements made at ½‐foot intervals was 052. This value compares favorably with the specific yields determined by tracer techniques and laboratory analysis of cores. However, the specific yield determined by the neutron method was 50% greater than the specific yield determined by pumping tests.
Unification of Data on Sediment Transport in Flumes by Similitude Principles
Authors: Willis Joe C. , Coleman Neil L.
Published: February 2008

Similitude criteria for flow with sediment transport are derived by normalizing equations of continuity and motion for flow in an alluvial channel. The well‐known Reynolds and Froude numbers are obtained as well as a transport similitude number that prescribes the sediment effects on the inertial, gravitational, and viscous forces acting in the flow system. The Froude number along with a similitude number for the median diameter of the sediment particles is found to specify transport similitude for various flume investigations. A unified correlation of sediment discharge data from numerous laboratory flume studies is developed through the similitude analysis.
Regional Variations of River Water Composition Resulting From Halite Solution, Mackenzie River Drainage Basin, Canada
Authors: Hitchon Brian , Levinson A. A. , Reeder S. W.
Published: February 2008

The composition of surface waters in the Mackenzie River drainage basin falls into three general groups: (1) rivers entering the Slave‐Mackenzie system from the west which have sum‐of‐constituents 100–200 mg/1 and chloride in the range < 1 mg/1 in their headwaters to 2–5 mg/1 at their mouths; (2) surface waters on the Canadian Shield which have lower sum‐of‐constituents (<100 mg/1) and chloride (<1 mg/1); and (3) the Slave and Mackenzie rivers and the Great Bear and Great Slave lakes, which have sum‐of‐constituents 100—200 mg/1 and chloride 5–10 mg/1. Hydraulic head cross sections with evidence of solution collapse structures and anomalous depositional thicknesses indicate extensive solution of Middle Devonian halite and movement of the resulting brines to discharge areas at the principal Devonian outcrop near the Slave River. Chemical and isotopic analysis of saline springs in the discharge area confirms an origin by solution of halite (and gypsum) by meteoric water.
A two‐stage optimization model for design of a multipurpose reservoir
Authors: Mobasheri Fereidoun , Harboe Ricardo C.
Published: February 2008

A mathematical model that can be useful in determining the optimum design and operation of a single multipurpose reservoir is presented. The development purposes include firm water supply, firm on‐peak and dump hydropower production, flood control, and low flow augmentation. The model is based upon a two‐stage optimization technique. It takes into account the fact that economic returns from a project are a function of both design and operational rules of the project. A dynamic programing algorithm which has a physical recursive equation computes the optimum operation policy of a feasible design. An iterative uniform grid sampling algorithm is then used to compare designs for which optimum operations are already determined and to select the best design. The model is applied to a hypothetical water resources project for illustrative purposes. The limitations of this mathematical model and some future research that may eliminate these limitations are discussed.
Snowmelt runoff from measurements of tritium and oxygen‐18
Authors: Dinçer T. , Payne B. R. , Florkowski T. , Martinec J. , Tongiorgi E.
Published: February 2008

During 1965–1967 the snowmelt runoff in a small mountain basin in Northern Czechoslovakia was studied by measuring the tritium and oxygen‐18 content of precipitation, snowpack, and runoff, in addition to an improved degree‐day method which was used as a standard tool. The results showed that about two‐thirds of the meltwater infiltrated to the soil, and the displaced water recharged during the previous years toward the stream channels. The tritium content of the baseflow and the subsurface runoff indicated that the mean residence time of the subsurface water in the basin was approximately 2.5 years with a standard deviation of 1.25 years. The volume of the subsurface storage was estimated to be 2.6×106 m3. The oxygen‐18 content of snow samples was in agreement with the tritium results on the relative contribution of the meltwater and subsurface runoff to the total runoff from the basin.
A graphic presentation of stream gain or loss as an aid in understanding streamflow characteristics
Authors: Koch Neil C.
Published: February 2008

A graphic presentation of cumulative monthly stream gain or loss on a given stream reach is used as a tool to show whether the stream gain or loss is apparent or real, and to determine the magnitude, time, and cause of the gain or loss. The graphic method could also be used to determine how much of the base flow is ground‐water discharge. Interpretations of the cumulative gain or loss graph are described for three reaches on the James River in northeastern South Dakota and southeastern North Dakota.
On the hierarchical structure of natural drainage systems
Authors: Mayer Hugo E.
Published: February 2008

A relation exists among four parameters of natural drainage systems. The parameters are: the bifurcation ratio, the stream length ratio, the basin area ratio, and the basin shape parameter. The bifurcation ratio is found to vary directly with the basin area ratio, and the stream length ratio raised to a power which is the reciprocal of the basin shape parameter. Bounds for the basin area ratio are determined by exploiting the fact that some streams of order i do not join streams of order i+1 but join streams of higher order. Those bounds, with given values for the basin shaped parameter, enable us to determine admissible regions for feasible pairs of values that the bifurcation and stream length ratios may assume. A plot of an admissible region and some associated tables are provided.
Note on evaluations of R/S for fractional noises and geophysical records
Authors: Taqqu Murad
Published: February 2008

In the computer program evaluating the statistic R/S, I have found a mistake affecting the figures in Mandelbrot and Wallis [1969 a, b, c, d]. Once the mistake is corrected the self‐similar model of hydrologie time series turns out to be even better than I would have thought from the above mentioned papers.

The mistake has an important effect only when the lag s is small. For small s, R(t, s) / S(t, s) as it appears in the papers' figures is often smaller than its true value, and the graph log R/S versus log s presents an important initial transient phase before the pox diagram becomes tightly aligned along a straight line of slope H. After correction this initial transient phase is greatly reduced. This reduction indicates that the penultimate behavior of R/S often starts at very small values of the lag.
Cost‐Sharing for Federal Water Resource Programs with Emphasis on Flood Protection
Authors: Loughlin James C.
Published: February 2008

Differences in cost‐sharing policy can cause inefficiencies and inequities to arise among and within federal water resource programs. Beneficiaries may not choose the least cost alternative, the optimal scale may not be chosen, and optimal use of existing capacity may not be realized. Equity problems include varying reimbursement requirements for similar, or the same programs; the ‘tilting’ of project costs toward nonreimbursable purposes; and the arbitrariness of existing cost‐sharing provisions. Case studies pertaining to flood control are presented illustrating several of the above points. A uniform cost‐sharing policy for flood protection is proposed.
Evaporation Measurements by an Eddy Correlation Method
Authors: Goltz S. M. , Tanner C. B. , Thurtell G. W. , Jones F. E.
Published: February 2008

Eddy correlation measurements of water vapor flux density have been made by using a barium fluoride film humidity sensor and a three‐dimensional anemometer. During morning and evening periods, good agreement was obtained between eddy correlation data and two independent methods. Serious disagreement between measurements occurred only when the humidity sensor was operating within a poorly defined portion of the calibration curve that was not suited to on‐line calculations. The results indicate that the humidity sensor could be modified to allow operation at all times within linear segments of the calibration curve, thereby permiting successful on‐line computer calculations of eddy correlation vapor flux within one meter of the surface.
Dissolved Solids‐Discharge Relationships: 1. Mixing Models
Authors: Hall Francis R.
Published: February 2008

With the increasing interest in the relationships between dissolved constituents and discharge in streams a reasonable basis is needed for the selection of possible models that might aid in analyzing the data. A series of simple mixing models based on mass balance calculations is presented along with derivations and solutions for certain assumptions about the mixing volumes and the storage volume‐discharge relationship. If concentration and discharge data show a hysteresis or loop relationship with time, then the commonly assumed direct relationship between total volume of water in the stream channel and stream discharge is probably not valid. The relationship of the constants in the derived equations to physical or chemical factors is masked at the present time by the nature of the initial assumptions and the method of derivation.
Flow from a Spherical Source with Water Content Dependent Diffusivity
Authors: Singh Rameshwar
Published: February 2008

Leakage of moisture from underground buried sources can occur in nature because of cracking or deterioration of confining surfaces. Leaking moisture can be radioactive or contaminated and may endanger public health. In disposal of such substances underground, consideration must be given to the extent of dispersal of moisture from wet containers in case of accidents. The movement of moisture from a spherical buried source into partially saturated surroundings is described by a nonlinear partial differential equation. Complexity of the equation prevents obtaining an explicit solution of the problem; however, an approximate solution has been extracted by the method of weighted residuals. The technique calls for representing the solution with a polynomial in space variable that has its coefficients as unknown functions of time, to be determined from the conditions and by satisfying the equation over the range of space variable in an averaging sense. This procedure accepts any kind of diffusivity function including numerical values obtained from experiments. The method is simple in its application and produces results that compare well with the known solution.
A Power Wind Law for Turbulent Transfer Computations
Authors: Brutsaert Wilfried , Yeh Gour‐Tsyh
Published: February 2008

The parameters C and m of a power law for the wind profile u = Cu*(z/z0)m, where u* is the friction velocity and z0 is the roughness length of the surface, are determined as functions of the roughness and of the Monin‐Obukhov stability length L through comparison with the log linear law for stable conditions and the interpolation law for unstable conditions. As expected, for neutral conditions the results show that m and C are approximately equal to 1/7 and 6, respectively. Parameter C increases slightly whereas m decreases with decreasing stability.
Playa Water Quality Changes with Time and Effects on Clarification
Authors: Lehman Oliver R. , Hauser Victor L.
Published: February 2008

An estimated 2 to 5 million acre‐feet of runoff water accumulates annually in playas on the semiarid southern high plains; however, development of this large potential water source has been impeded by lack of water quality data. Most of the water is lost by evaporation, and timely utilization is essential. Therefore, a particular need exists for quality data on freshly impounded water. Water from five playas was sampled and analyzed at intervals for 24 days following runoff from a single storm. Chemical analyses showed playa waters were excellent for irrigation; however, adequate economical clarification is probably needed for such projects as direct aquifer injection. With aging, less synthetic cationic polyelectrolyte and more alum was required for water clarification. Initially low nitrate and chemical oxygen demand values decreased with time.
Need for Saline Groundwater Data To Advance Desalting Technology
Authors: Rinne W. W.
Published: February 2008

The use of desalting technology to supplement the water resources in semiarid areas of the United States indicates the need for more detailed information on the quantity and quality of saline groundwater supplies. The disposal of brine, a waste product of all desalting processes, poses a formidable problem at inland plant sites. Present work indicates that solar evaporation ponds and subsurface injection are the preferred methods of disposal. The latter method, if employed, would require more data and information on the geologic and hydrologic features of subsurface formations. Systems studies relating the intake and brine disposal facilities with the desalting process are being conducted to achieve optimum system economics.
A Flood Insurance Model for Sharing the Costs of Flood Protection
Authors: Loughlin James C.
Published: February 2008

To encourage optimal future use of the floodplains, Congress in 1968 passed the Federal Flood Insurance Program. Under this program, existing occupants would pay a chargeable or a subsidized premium whereas future developers would pay the full actuarial premium. A complementary cost sharing model for structural flood protection programs is proposed related to savings in flood insurance premiums. With this model, existing occupants would share flood protection costs allocated to them in the proportion that reductions in their chargeable premiums and noninsurable damages (i.e., local benefits) bear to the total benefits to existing developments. This amount would vary from project to project. Future developers would share in costs allocated to them in the proportion that reductions in their actuarial premiums and noninsurable damages (i.e., local benefits) bear to the total benefits to future developments. Thus they would be paying 100% of the costs allocated to future developments, inasmuch as the full actuarial premium and all uninsured damages are the responsibility of future developers under the flood insurance program. The magnitude of the cost shares with this model is computed for a sample of 57 U.S. Army Corps of Engineers projects indicating a total local contribution of about 75% of total capitalized flood protection project costs.
Effect of Soil Moisture Hysteresis on the Water Table Profile Around a Gravity Well
Authors: Guitjens J. C. , Luthin James N.
Published: February 2008

Gravity wells, pumped intermittently, can have different degrees of drainage in the unsaturated zone at the onset of water table recovery. Each part of the aquifer profile follows a specific scanning curve of rewetting. The measured hysteresis phenomenon of Oso Flaco fine sand and the hydraulic conductivity as a function of moisture content are incorporated in the finite difference form of the partial differential equations for steady and unsteady radial flow to solve for the soil moisture pressure distribution of one water table drawdown and three different kinds of recovery. The method of independent domains describes the hysteresis phenomenon and accounts for a gradual release and uptake of water rather than constant changes based on the concept of specific yield. Small differences between the computed values of the three water table recoveries, each one starting at a different degree of drainage in the zone above the water table, are probably due to the relatively small unsaturated portion of the aquifer profile.
Three‐Dimensional, Transient, Saturated‐Unsaturated Flow in a Groundwater Basin
Authors: Freeze R. Allan
Published: February 2008

A three‐dimensional finite difference model has been developed for the treatment of saturated‐unsaturated transient flow in small nonhomogeneous, anisotropic geologic basins. The uniqueness of the model lies in its inclusion of the unsaturated zone in a basin wide model that can also handle both confined and unconfined saturated aquifers, under both natural and developed conditions. The integrated equation of flow is solved by the line successive overrelaxation technique. The model allows any generalized region shape and any configuration of time variant boundary conditions. When applied to natural flow systems, the model provides quantitative hydrographs of surface infiltration, groundwater recharge, water table depth, and stream base flow. Results of simulations for hypothetical basins provide insight into the mechanisms involved in the development of perched water tables. The unsaturated basin response is identified as the controlling factor in determining the nature of the base flow hydrograph. Application of the model to developed basins allows one to simulate not only the manner in which groundwater withdrawals are transmitted through the aquifers, but also the changes in the rates of groundwater recharge and discharge induced by the withdrawals. For any proposed pumping pattern, it is possible to predict the maximum basin yield that can be sustained by a flow system in equilibrium with the recharge‐discharge characteristics of the basin.
Introduction to Bayesian Methods Using the Thomas‐Fiering Model
Authors: Conover W. J.
Published: February 2008

Investment decisions in water resources planning depend on estimation of unknown parameters. The Bayesian approach to estimation involves use of the estimator that minimizes the expected risk, where risk is the expected loss. Bayes' estimators may be used in a wide variety of situations for which probabilistic models have been specified. In an example, a Bayes estimator of the serial correlation coefficient in streamflow is shown to be a weighted average of the sample serial correlation coefficient and the mean of all population serial correlation coefficients.
Some Efficient Dynamic Programing Algorithms for the Optimal Sequencing and Scheduling of Water Supply Projects
Authors: Morin Thomas L. , Esogbue Augustine M. O.
Published: February 2008

The sequencing and scheduling aspects of some important capacity expansion problems encountered in water resources development are studied. Dynamic programing algorithms are developed for both project timing problems and combined project selection and timing problems involving durable high cost water supply projects, which in the aggregate are subject to continuous time demand requirements. The structure of the problems is successfully exploited to produce computationally efficient algorithms to solve problems of the dimension encountered in water resources systems. The computational superiority of these algorithms over conventional dynamic programing algorithms is discussed and illustrated by a numerical example.
Migration of Pollutants in a Glacial Outwash Environment, 3
Authors: Crosby James W. , Johnstone Donald L. , Fenton Robert L.
Published: February 2008

Continued investigations of the drain field environment in the Spokane Valley of eastern Washington strengthen earlier conclusions. Very high prevalent moisture tensions, at depth, are related to a lack of deep fluid percolation and lateral movement of waste waters is assumed. Downward movement of chemical pollutants cannot be demonstrated but may occur during early stages of drain field operation. Migration of bacteria is restricted to a relatively few feet from the leach bed. Routine monitoring of groundwater quality did not at any time produce positive results for coliform bacteria. Neither could the chemical quality of the groundwater be related to drain field operation. Local areas where problems have been associated with the use of septic tanks and drain fields appear to be restricted to marginal valley settings where geologic conditions are vastly different.
Method of Calculating Secondary Flow
Authors: Chiu Chao‐Lin , Lee Teh‐Shee
Published: February 2008

Secondary flow plays an important role in a number of areas in hydraulics, such as sediment transport, distribution of primary flow velocity and boundary shear, flow resistance, and stream meandering. In this study, secondary currents generated in a straight, triangular open channel are investigated and used to develop a method of calculating secondary flow in an entire transverse cross section of a straight channel. The method developed involves the use in different regions of a cross section of different sets of curvilinear coordinate systems consisting of isovels of primary flow and their orthogonal trajectories. Descriptions of the method as well as calculated results are presented.
Optimal Angles of Stream Junction: Geometric, Stability to Capture, and Minimum Power Criteria
Authors: Howard Alan D.
Published: February 2008

The angles of junction of streams adjust by erosion and sedimentation at the junction until the water surfaces and floodplains merge accordantly with each other and with the stream segment continuing downstream. A simplified geometric model of the zone of merger predicts angles of junction determined by the gradient relationships at the junction that are close to those in badland rill and gully networks. Merging streams with these predicted angles of junction should not be subject to discrete capture by each other or by their downstream continuation. Evaluation of angles of junction with regard to minimum rate of work performed by gravity produces normative equations for these angles that are unexplainedly similar to those predicted by the geometric model within the range of rates of downstream decrease of gradient typical of natural streams.
Use of Fluorescein To Measure the Composition of Waterdrop Splash
Authors: Timmons D. R. , Mutchler C. K. , Sherstad E. M.
Published: February 2008

Fluorescein, a fluorescent compound, was used as a tracer to measure the amount of waterdrop water in splash after impact of the waterdrop in various depths of water. The addition to water of up to 50 ppm of fluorescein caused negligible changes in liquid density, surface tension, and viscosity. The tracer technique was successfully used to show the proportions of waterdrop water in splash from varying depths of target water.
Determination of Nonlinear Functional Response Functions in Rainfall‐Runoff Processes
Authors: Amorocho J. , Brandstetter A.
Published: February 2008

The operation of some hydrologie systems can be represented by a functional series expansion involving higher order nonlinear generalizations of the convolution integral, which underlies the unit hydrograph concept. A method was developed to determine the linear and nonlinear response functions of such systems on the basis of concurrent records of the input and output. This procedure was successfully tested in a special laboratory catchment and in a natural watershed to establish rainfall‐runoff relations.
Estuary Water Temperature Sensitivity to Meteorologie Conditions
Authors: Young G. K. , Tseng M. T. , Taylor R. S.
Published: February 2008

Determination of the time history of water temperature in an estuary is accomplished by using a thermal quality model in conjunction with a hydrodynamic simulation model. The hydrodynamic model computes tidal stages and flows throughout the estuary for any tidal cycle. The thermal quality model uses the results of the hydrodynamic model and observed meteorologic data to predict water temperatures. These models have been used successfully in case studies to reproduce observed water temperatures. The sensitivity of the resulting temperatures to the various meteorologic parameters, such as wind conditions, dew point temperature, and solar radiation, is presented. Dew point temperature is shown to exert a major influence on water temperature.
An Intersectoral Programing Model for the Management of the Waste Water Economy of the San Francisco Bay Region
Authors: Bargur J. S. , Davis H. C. , Lofting E. M.
Published: February 2008

The usefulness of interindustry models for regional water resource and broader environmental studies is becoming increasingly apparent. Data requirements may appear formidable; however, secondary data sources can be adequate for many aspects of analysis. An intersectoral model for the nine‐county San Francisco Bay region was constructed from secondary data and used to develop pollution coefficients for several specific waste constituents, both conservative and nonconservative. Intersectoral programing methods in conjunction with a steady state linear optimal dispersion model of the bay were used to determine the levels of waste treatment necessary to meet quality standards for future time frames.
Direct Field Determination of the Natural Reaeration Coecient by Frequency Response Analysis
Authors: Shieth Yei‐Shong , Davidson Burton
Published: February 2008

By means of a mechanical instream aerator operated in a sinusoidal fashion with a known amplitude and frequency, it is possible to determine quantitatively the value of the natural reaeration coefficient from chosen field measurements of dissolved oxygen (DO) concentration. The method uses a mechanical aerator as a boundary condition in conjunction with a detailed one‐dimensional, unsteady state Streeter‐Phelps model of a polluted river. By means of an analysis Au Gres sand and of parent material in Grayling sand, (c) Gravity yield in relation to depth for of the DO variation with time at a fixed distance downstream from the forcing function at the end of the transient period, the natural reaeration coefficient can be uncoupled parametrically from the biochemical removal coefficient, the benthal demand factor, and the respiration term in a unique way. The frequency response method of determining the natural reaeration coefficient under dynamic field conditions has widespread applicability in water pollution analysis.
Electromagnetic Dispersion Curves for Natural Waters
Authors: Lepley Larry K. , Adams William M.
Published: February 2008

The dispersion curves of the electromagnetic properties of water to radiation of 106 to 1.3 × 1010 Hz at normal incidence are computed and plotted for 39 salinity and temperature combinations. The elementary theoretical basis of these calculations is given in a tutorial presentation. These graphs indicate that the frequency dispersion of the reflectance of radio energy in the 106‐ to 109‐Hz band at normal incidence to a smooth water surface is strongly influenced by the salinity of the water and that the spectral signature can be used as a measure of water salinity as distinguished from water temperature. These curves should be of value to workers in remote sensing, hydrology, and limnology.
Dynamic Simulation of Vertical Infiltration into Unsaturated Soils
Authors: Bhuiyan S. I. , Hiler E. A. , Van Bavel C. H. M. , Aston A. R.
Published: February 2008

A dynamic simulation language (S/360 CSMP) was used to develop a computer model that simulated the vertical infiltration of water into unsaturated soil. The modeling concept consisted primarily of dividing the soil into a large number of layers of equal thickness. The net flux of water through each layer at any particular time was established by using the principles of conservation of mass and Darcy's law. The ensuing water content was then calculated by integrating the net flux by means of the fourth order Runge‐Kutta method with suitable error criteria. The cumulative infiltration was calculated from the instantaneous infiltration rates by using the same integration technique. Water content profiles with time were obtained for three different soils: (1) Yolo light clay, (2) Adelanto loam, and (3) Pachappa loam. The infiltration rate and cumulative amount were also calculated with time, a complete picture of the water intake characteristics of the soil thus being given. Our simulation results for Yolo light clay were compared with those obtained by Philip under identical boundary and initial conditions. The principal advantage of the numerical procedure is its complete generality and the ease with which numerical data on the hydraulic characteristics of the soil may be used without arbitrary assumptions or function‐fitting procedures. Also, soil inhomogeneity and special boundary conditions can easily be specified in refinements of the present program.
Ocean Sludge Disposal by Barges
Authors: Koh Robert C. Y.
Published: February 2008

A simple model is constructed to examine the dispersion and settling of wastes such as sewage sludge or dredge spoils discharged from barges into the ocean. Several example cases are analyzed using the model; it is found that the proper choice of disposal depends strongly on the local environmental conditions and the characteristics of the waste.
Bayesian decision theory applied to design in hydrology
Authors: Davis Donald R. , Kisiel Chester C. , Duckstein Lucien
Published: February 2008

The role of Bayesian decision theory in hydrologic design problems is presented both in theory and by example. The theory is applied to an actual flood levee design problem on the Rillito Creek floodplain in Tucson, Arizona. Computer solutions provide a basis for judging the costs of overdesign in the face of uncertainty in the parameters of the flood frequency model (log normal) and for determining the worth of hydrologic data. One conclusion is that decision theoretic analysis looks at the decision situation from the standpoint of the engineer: how can one best decide in the face of limited data and the present knowledge about system behavior?
A water yield model for small watersheds
Authors: Haan C. T.
Published: February 2008

Studies on seven small watersheds have shown that monthly runoff can be satisfactorily predicted from a self‐calibrating four‐parameter model. The model requires as input the estimated average potential evapotranspiration and the daily rainfall. In addition at least one and preferably two or three years of observed monthly flows are required for parameter estimation. The model is adaptable to a wide range of hydrologic conditions.
Automatic sampler for dye tracer studies
Authors: Kilpatrick F. A.
Published: February 2008

A simple, largely mechanical device for automatically collecting periodic discrete water samples for use in dye tracer studies has been developed and successfully used by the U.S. Geological Survey. The device consists essentially of two rows of spring‐loaded hypodermic syringes that are released from their closed position at selected time intervals to draw in and retain the desired water samples. The sampler is mounted in a boatlike structure partially immersed in the flow to be sampled.
The NAR Study: A case study in systems analysis
Authors: Schwarz Harry E.
Published: February 2008

Water resource planning should be objective oriented, must strive to search out as many alternatives as practicable, must be flexible to respond to changes in conditions, objectives, and values, and should be a continuous process rather than culminating in a single final plan. The methods of systems analysis were found to be applicable, and three models were considered. Two of these models, a demand model and a supply model for water withdrawal uses, appeared to be practical within the limits of data and time. The specifications for the demand model included consistent economic parameters, the separation of procedures for the economic and technologic assumptions, the separation of demands into broad water quality groups, the ability to aggregate data, the simplification of input data modification, the production of self‐explanatory outputs, and complete control by the user of all the input and output functions. The specifications for the supply model included compatibility with the demand model, use of generalized cost curves for six supply categories, use of hydrologic and instream use constraints, and optimization by cost minimization.
New concept in hydrograph analysis
Authors: Rogers W. F.
Published: February 2008

Channel length frequency distribution is a new drainage basin parameter that has a qualitative relationship to the surface runoff hydrograph. Measurements of the distance from the basin outlet along the drainage channel to the head of each first order channel form a random distribution of distances. Frequency histograms of these distances, when compared with the surface runoff hydrograph from general storms, show consistent similarity. Some implications involving these similarities are that (1) first order channels are source areas of surface runoff, (2) concentrations of similar first order channel distances account for the hydrograph peak and secondary hydrograph peaks, (3) the timing of delivery of surface runoff to the outlet influences the hydrograph rise time and base width, (4) surface runoff occurs lower on the hydrograph recession limb than is generally assumed, (5) arbitrary base flow and interflow separation has questionable validity, (6) the distribution of first order channels in a drainage basin reflects the influence of geology on surface runoff, (7) channel length frequency distribution influences the distribution of unit volume runoff for unit hydrographs, and (8) channel length frequency distribution alone can account for variations in hydrograph peaks of otherwise homogeneous drainage basins.
Unsteady radial flow in an unconfined aquifer
Authors: Streltsova T. D.
Published: February 2008

The partial differential equations are deduced for unsteady radial flow to a well that is tapping an unconfined aquifer of infinite extent and discharging at a constant rate. Complete penetration of the aquifer by the well is assumed. Consideration is given to the average head, which is the observational head in a well that is screened throughout the unconfined aquifer, as well as to the head that corresponds to the free surface value. A relationship between the average head and the free surface head is assumed to be in the form of a vertical transfer linear equation.
Environmental adjustments for the airborne radiation thermometer measuring water surface temperature
Authors: Shaw R. W. , Irbe J. G.
Published: February 2008

An evaluation was made of the combined effects on airborne radiation thermometer (Art) readings in the 8–14 μm region of the emissivity of the water whose surface temperature is being measured, the infrared radiation from water vapor and carbon dioxide in the optical path, and the radiation reflected from the surface of the water. The water vapor and carbon dioxide in the optical path beneath the aircraft contributed 10–25% of the measured radiation; gaseous radiation reflected from the water contributed 0.1–0.6%. Radiation emitted from an overcast cloud layer (other than cirrus) and reflected from the water increased the Art reading by 0.5°C. The environmental adjustment reduced the root‐mean‐square difference between Art readings and a ship bucket thermometer from 1.7 to 0.6°C for 27 cases. A simple rapid graphic method based on the theoretical model was used on 51 cases at different aircraft heights and widely varying meteorologic conditions and produced a similar improvement.
Zone of flow establishment for round buoyant jets
Authors: Hirst Eric
Published: February 2008

A method is developed to predict physical properties within the zone of flow establishment (ZFE) for thermal effluents discharged as buoyant jets through round submerged diffusers. The ZFE is the region immediately beyond the diffuser exit in which the mean flow profiles undergo a transition from their internal flow shapes to a free turbulent flow condition. The integral equations of mass, energy, and momentum conservation are used. The solution includes the length of the ZFE and the values of jet width, jet orientation, and center line temperature throughout this zone. The method can predict buoyant jets with three‐dimensional trajectories discharged to flowing stratified ambients. Results obtained with the method agree well with the limited experimental data available and with existing empirical correlations. These results provide the necessary initial conditions for conventional (applicable only in the zone of established flow) jet prediction methods; and thus the accuracy of hydrothermal predictions of thermal effluents from power plants will be improved.
Role of subsurface flow in generating surface runoff: 2. Upstream source areas
Authors: Freeze R. Allan
Published: February 2008

Runoff simulation for rainfall events on hypothetical upstream source areas, carried out with a deterministic mathematical model that couples channel flow and saturated‐unsaturated subsurface flow, provides theoretical support for the runoff‐generating mechanisms observed in the field by Ragan and Dunne. The simulations show that there are stringent limitations on the occurrence of subsurface storm flow as a quantitatively significant runoff component. Only on convex hillslopes that feed deeply incised channels, and then only when saturated soil conductivities are very large, is subsurface storm flow a feasible mechanism. On concave slopes with lower permeabilities, and on all convex slopes, hydrographs are dominated by direct runoff through very short overland flow paths from precipitation on transient near‐channel wetlands. On these wetlands surface saturation occurs from below because of rising water tables that are fed by vertical infiltration rather than by lateral subsurface flow. These conclusions, when coupled with field observations that show classic Hortonian overland flow to be a rare occurrence in vegetated humid environments, have implications in the planning of field instrumentation networks, and in the designing of hydrologic response models.