bluuebunny/crossref_metadata_2025 huggingface dataset:
A systems approach to assessment of rural water supply program effectiveness
Authors: Frankel Richard J.
Published: February 2008

Systems analysis was used to improve the methodology of impact evaluation by determining the role of resource constraints and complementary inputs in the development of the rural water supply program in Thailand. An impact evaluation was undertaken to analyze the effectiveness of the National Potable Water Project and to provide feedback to the government for improving the administrative, technical, and operational aspects of the program. Objectives of the evaluation were to provide guidelines for design, construction, finance, and administration of the potable water projects; operational guidance for management; information for training plant operators; and feedback on villager attitudes, water habits, water use, and village development. The methodology developed measured the social, economic, and public health implications of the water projects toward achieving rural community development. Data are being collected from some 165 village projects throughout northeast Thailand.
The influence of geological membranes on the geochemistry of subsurface waters from Miocene sediments at Kettleman North Dome in California
Authors: Kharaka Yousif K. , Berry Frederick A. F.
Published: February 2008

A detailed account of the geology, regional hydrodynamics, isotopic data, and formation water chemistry of the Kettleman North Dome oil field in California indicates that the waters from the Temblor formation (Miocene) are principally meteoric in origin, related to recharge areas located to the west. Their concentration relative to meteoric water is attributed to hyperfiltration through geological membranes as well as to water‐rock interactions. The chemistry of the waters in each subzone of the Temblor formation is characteristic of that subzone and shows membrane effluent characteristics to a given subzone with respect to the one stratigraphically below it. The chemical relations are attributed to increased efficiency of shale membranes with increased depth of burial. Membrane behavior of shales controls completely or in part the distribution of the following ratios: Li/Na, Rb/Na, NH3/Na, Mg/Ca, Sr/Ca, Ca/Na, alkalinity/Cl, SO4/Cl, I/Br, and B/Cl. Some of these ratios are modified by temperature‐controlled water‐rock interactions. The K/Na ratios and the SiO2 and Ba concentrations, on the other hand, are completely dependent on water‐rock interactions.
Autocorrelation structure of monthly streamflows
Authors: Moss Marshall E. , Bryson Maurice C.
Published: February 2008

The autocorrelation structure of monthly streamflows, a nonstationary process, is developed from a mathematical model that assumes that monthly precipitation is an independent series and that the base flow of the stream is derived from a linear aquifer. Under these assumptions the first‐order autocorrelation coefficients of streamflow are found to vary seasonally, as do other statistics such as monthly means and standard deviations. Comparison of the autocorrelation coefficients predicted by the model with those computed from an actual streamflow record of 58 years indicates that the seasonality of streamflow is well represented by the model.
Two‐distribution method for modeling and sequential generation of monthly streamflows
Authors: Singh K. P. , Lonnquist C. G.
Published: February 2008

Distributions of observed monthly streamflows at many gaging stations exhibit slight, moderate, or sharp reverse curvatures that cannot be accommodated by the commonly used classical distributions such as the normal and gamma (Pearson type 3) distributions applied to flows or their logarithms. The two distribution, essentially a bimodal distribution, fits most of these observed distributions very well. Herein is presented a unique and versatile method for modeling and sequential generation of monthly streamflows. In order to assure the normality of the multivariate distribution of variables representing monthly flows the flows or their logarithms are converted to standardized normal deviates by suitable transforms. The distributions of monthly streamflows generated by the two‐distribution method fit best the observed flow distributions. Annual flows obtained by summing generated monthly flows fit the observed annual flows very well. The use of the two‐distribution method can obviate arbitrary adjustments in generated monthly flows to bring the annual flows obtained from them in line with observed annual flows.
Galerkin approximation of the time derivative in the finite element analysis of groundwater flow
Authors: Gray William G. , Pinder George F.
Published: February 2008

Whereas considerable effort has been expended in generating approximations to the spatial derivatives encountered in porous media flow, the time derivative has received relatively little attention. In spite of the fact that sophisticated finite element formulations have been developed for the spatial derivatives, finite difference methods are generally applied to the time derivative. The Galerkin method of approximation permits a high‐order approximation in time as well as in space. The resulting approximate equations have been successfully solved by using a prismatic element with triangular cross section. The time axis runs the length of the prism and is subdivided into elements that may be linear, quadratic, or cubic. Because this formulation requires in general the solution for several time levels simultaneously, there is a resulting increase in computer time required to solve the larger matrix. Numerical experiments indicate that the selection of an optimum numerical scheme is dependent not only on the particular problem considered but also on the sequence of time steps used.
Effects of agricultural acreage reduction on water availability and salinity in the Upper Colorado River Basin
Authors: Howe Charles W. , Orr Douglas V.
Published: February 2008

Consideration is given to the costs in terms of regional income likely to be lost if irrigated acreages were to be reduced in the Upper Main Stem subbasin of the Colorado River as a means of freeing water for alternative uses and reducing salt loadings. The cost estimates, known to be biased upward, appear competitive with other water augmentation and salinity reduction programs.
Mineralogy of suspended sediment and concentration of Fe, Mn, Ni, Zn, Cu, and Pb in water and Fe, Mn, and Pb in suspended load of selected Kansas streams
Authors: Angino E. E. , Magnuson L. M. , Waugh T. C.
Published: February 2008

When concentration levels of the elements studied in the suspended sediment are compared to average reported values for shales, they show Fe to be low. The other elements are higher. Values for these elements in the dissolved portion are variable, reflecting in some cases possibly lithologic differences. The dissolved trace element composition of the water is not reflected in the chemistry of the detrital load. X‐ray diffraction study of the mineralogical content of the suspended sediment indicated that mortmorillonite was the clay mineral present in all cases. Other minerals present in almost all the samples were calcite and quartz. Gypsum, dolomite, feldspar, illite, and kaolinite were present in lesser amounts in some of the samples. Some question of the source of specific trace elements in these stream waters exists. For Ni and Pb, however, pollution is a possible source. The iron and manganese levels in the suspended sediments of all streams are not unusual. Significant correlations of the Pb with Mn and Fe are strongly suggestive of coprecipitation with Fe and Mn oxides.
More on an approximate solution for nonlinear diffusion
Authors: Brutsaert Wilfried
Published: February 2008

A method of solution developed earlier (1970) for a diffusivity, that is, a power function of concentration, is shown to be more generally applicable. One of the conditions of its applicability is the existence of a sharp diffusing front. As an illustration the solution is worked out herein for a diffusivity that has been useful in the analysis of soil water problems.
The effects of streamflow variation on production and income of irrigated farms operating under the doctrine of prior appropriation
Authors: Anderson Raymond L.
Published: February 2008

Many irrigated farms dependent upon varying streamflow frequently encounter periods of inadequate water supply because streamflow is inadequate to serve all water rights. Streams fed by mountain snowmelt exhibit sharply peaked hydrographs. During the peak runoff period most water rights can be served. Thereafter streamflow declines rapidly, and many of the later water rights are denied water. Farms that are prohibited from diverting water suffer reduction in crop yields and income. To get the most benefit from varying flow, streams must be closely monitored so that as many rights as possible can be served with the original flow and the return flow that occurs.
Markov mixture models for drought lengths
Authors: Jackson Barbara Bund
Published: February 2008

Markov mixture models combine a Markov model for transitions between low and normal streamflow states with a mixture model blending two normal subpopulations. The models are particularly effective for generating synthetic streamflow records with long and severe droughts. Their use in a hypothetical planning problem illustrates the application of a set of modeling precepts.
A Galerkin‐finite element technique for calculating the transient position of the saltwater front
Authors: Segol Genevieve , Pinder George F. , Gray William G.
Published: February 2008

The set of nonlinear partial differential equations that describe the movement of the saltwater front in a coastal aquifer is solved by the Galerkin‐finite element method. Pressure and velocities are obtained simultaneously in order to guarantee continuity of velocities between elements. A layered aquifer is modeled either with a functional representation of permeability or by a constant value of permeability over each element.
Systems evaluation of village water supply and treatment in Thailand
Authors: Frankel Richard J.
Published: February 2008

A systematic evaluation was made of 165 village water supply and treatment systems in Northeast Thailand for studying problems involved in the design, construction, operation, administration, and financing of such systems. The evaluation included 1 year of field data collection covering system operation by village operators. This is believed to be the first such evaluation of the effectiveness of a rural water supply development program. Findings include quantification of strengths and weaknesses pertinent to management, and recommendations are developed for guiding governmental agencies operating such programs and international agencies participating in their planning and financing.
Comparison of precipitation gage catches with a modified alter and a rigid alter type windshield
Authors: Rawls Walter J. , Robertson David C. , Zuzel John F. , Hamon W. R.
Published: February 2008

Gage catch from two standard weighing recording rain gages (Belfort model 5‐780), one with a modified Alter windshield and one with a rigid Alter type windshield, were compared for 89 storms with wind speeds ranging from 4 to 32 mph (6.4 to 51.5 km/h) and temperatures ranging from 14° to 69°F (−10° to 21°C). The differences between gage catches were statistically significant at the 1% level for wind speeds of 12 to 16 mph (19.3 to 25.7 km/h) and for temperatures of 23°F (−5°C) or less. Since on the average the windshields do not produce significantly different catches, either windshield can be used to compute actual precipitation by using the Hamon dual gage approach.
Changes in storm hydrographs after road building and clear‐cutting in the Oregon Coast Range
Authors: Harr R. Dennis , Harper Warren C. , Krygier James T. , Hsieh Frederic S.
Published: February 2008

Changes in storm hydrographs after road building, clear‐cutting, and burning were determined for six small watersheds in the Oregon Coast Range. Peak flows were increased significantly after road building, but only when roads occupied at least 12% of the watershed. Roads had no detectable effect on volumes of storm hydrographs. By reducing transpiration and interception, partial clear‐cutting increased peak flow, quick flow, delayed flow, and total storm hydrograph volume of some streams. Most increases were largest in the fall when maximum differences in soil water content existed between cut and uncut watersheds. Maximum increases in storm flow occurred after a 175‐acre watershed was 82% clear‐cut. Here peak flow increased 16 ft3/s/mi2, quick flow 1.5 in., and total storm hydrograph volume 2.6 in. during the fall. The average increase in winter peak flows was smaller. The effect of roads on peak flows has significance for design of culverts and bridges in headwater areas, but probably does not influence downstream flooding. Increases in streamflow after clear‐cutting should have no appreciable effect on either damage to bridges and culverts in headwater areas or downstream flooding. Caution must be used in extending results of this study to storm runoff events of low frequency and large magnitude.
Regional hydrochemistry of North American carbonate terrains
Authors: Harmon Russell S. , White William B. , Drake John J. , Hess John W.
Published: February 2008

The chemical variation of water samples drawn from carbonate terrains between southern Canada and northern Mexico is shown to be divisible into, first, variations at the local level due to (1) hydrogeologic conditions (time independent), (2) short‐term fluctuations of hydrologic factors (stochastic in time), and (3) seasonal fluctuations of such factors as temperature, precipitation, and plant growth (systematic in time) and, second, regional climatic effects. These regional climatic effects can be satisfactorily represented by mean annual groundwater temperature variation. The regional variation only emerges clearly if care is taken to compare water samples from the same hydrologic class, in this case, springwater. The partial pressure of carbon dioxide with which a springwater sample is in equilibrium is well represented by log Pco2 = a + bT, where a is of the order of −3.5 and b is approximately 0.07 with Pco2 in atmospheres and T in degrees Celsius.
Determining aquifer coefficients from residual drawdown data
Authors: Berg A. Vanden
Published: February 2008

Hantush's equation for the drawdown in a leaky, infinite aquifer, adapted to the residual drawdown, is used to obtain a least sum of squares fit to the residual drawdown measurements in an observation well by iteratively adjusting the transmissivity, storativity, and leakage factor. First estimates for the least squares method are obtained by first fitting the equation, with a fixed high value of the leakage factor, to two points of the data; this is followed by a number of fits to three points, each fit yielding a set of values for the three aquifer coefficients; the set which yields the least sum of squares is selected as first estimate to the main routine. An application to data from a pump test at Chatham, New Brunswick, is shown as an example.
A device for evaluating the water vapor exchange between snow and air
Authors: Cox Lloyd M. , Zuzel John F. , Perkins Lee
Published: February 2008

This paper describes a device developed for evaluating net vapor exchanges between snow and air that minimizes many of the errors inherent in pan measurements and provides a measurement of snowmelt during the study period. It consists of (1) a cylinder for holding an ‘undisturbed’ snow core, (2) a melt collection chamber, and (3) hydraulic pistons for maintaining the snow core level with the melting snow surface.

The change in weight of the snow core with time is a measure of the net vapor exchange between the air and the snow. Results are presented for seven 14‐hour days during May–June 1972 and six 24‐hour days during May–June 1973. The study site is located on sagebrush rangeland on the Reynolds Creek Experimental Watershed in southwest Idaho at an elevation of 2.13km.
Shapes of steady state perched groundwater mounds
Authors: Khan Muhammad Yunus , Kirkham Don , Handy R. L.
Published: February 2008

A potential theory flow solution for the potential function, stream function, and shape of the water table is given for a class of steady state two‐ and three‐dimensional perched groundwater mounds formed under a long rectangular recharge basin or under a circular recharge basin. The solutions are done by a Gram‐Schmidt method and a simple iteration scheme. The mounds are formed in a stratum of conductivity k1 overlying a perching stratum of much lower conductivity k2. Capillary fringe effects are neglected. The recharge rate is R. Potential theory mound heights are compared with those given by the Dupuit‐Forchheimer (DF) theory. For the cases computed (R/k2 = 10, 100, and 500 and k1/k2 = 50,100, 500, 600, 750, and 1000) the DF theory gives apex heights of mounds correct to better than 7% for two‐ dimensional mounds. For three‐dimensional mounds the DF theory gives in one case a mound height that is 69% too low (for R/k2 = 500 and k1/k2 = 600) and in another case a mound height that is 28% too low (for R/k2 = 500 and k1/k2 = 1000). Profiles of the computed mounds are graphed, and examples of use of the graphs in applications are given. Sample flow nets are presented.
The hypsometric integral and low streamflow in two Pennsylvania provinces
Authors: Kowall Stephen J.
Published: February 2008

Summer streamflow duration and base flow recession curves for eight watersheds draining sandstone‐siltstone‐shale terranes in the Appalachian Plateau and Folded Appalachian Mountains of Pennsylvania reflect variations in areal distribution and state of structural deformation of shallower lithologic units. The hypsometric integral (HI) has been used as a rapid reconnaissance technique to evaluate hydrology characteristics and to quantify the effects of lithology and structural deformation on low streamflow. The HI provides a measure of the areal extent of sandstone in each watershed, and the magnitude of summer streamflow (ft3/s/mi2) increases as the value of the integral increases, to indicate a higher percent of sandstone. Streamflow duration data from the two provinces show that siltstone‐shale areas in the mountain province can produce as much low streamflow per unit area as sandstone areas in the plateau province.
Quantifying societal goals: Development of a weighting methodology
Authors: Gum Russell L. , Roefs Theodore G. , Kimball Dan B.
Published: February 2008

The basic structure of the Techcom planning methodology is reviewed. In the context of this system a weighting methodology is developed to measure preferences regarding the attainment of postulated societal goals. The selected methodology, the Metfessel general allocation test, is applied to the hierarchies of three Techcom goals relating to aesthetics, economics, and recreation. The weighting methodology is tested with answers to a mail questionnaire randomly distributed throughout Arizona and New Mexico. Examples of the resulting preference weights are presented, and the use of such measures by decision makers discussed.
A stable estimator for linear models: 1. Theoretical development and Monte Carlo Experiments
Authors: Natale L. , Todini E.
Published: February 2008

Instant unit hydrograph (IUH) type linear models have been widely used to simulate many hydrologic systems. Unfortunately, the classical parameter estimators used to calibrate this type of model often fail to give a reliable and meaningful solution. It has been suggested that a set of constraints that can be deduced from the physics of the hydrologic system be imposed on the IUH in order to reduce the high sensitivity of the classical estimators to errors in the available data. Therefore a mathematically correct constrained estimator has been devised, and its solution is obtained by using quadratic programing. The higher degree of efficiency of this estimator (smaller dispersion of the estimates about the true value) is shown numerically through Monte Carlo experiments.
Optimal estimation of DO, BOD, and stream parameters using a dynamic discrete time model
Authors: Koivo A. J. , Phillips G.
Published: February 2008

A modified Streeter‐Phelps equation is used as the starting equation to obtain a discrete time mathematical representation which represents a model for the biological oxygen demand and the dissolved oxygen concentrations in a polluted stream. The unknown parameters to be estimated are treated as state variables in order to compute their numerical values from noise‐corrupted measurements. An optimal estimator is constructed for the estimation of the unknown parameters. The optimization scheme can be implemented in a small computer. The approach is illustrated by a numerical example.
Conversion of irregular finite element grid data to regular grid for three‐dimensional computer plotting
Authors: Gupta S. K. , Morrissey Michael W. , Lonczak John , Tanji K. K.
Published: February 2008

Three‐dimensional plotting provides a useful means for the illustration and interpretation of results from finite element simulation. The computer graphic packages usually available at computer centers, however, require data on regular grids and thus are not adaptable to isoparametric finite elements, which are combinations of various shapes and sizes of trapezoids. By using the basis functions, a method is presented for the estimation of regular grid values from irregular gridded data for plotting purposes.
Variation of link magnitude with map scale
Authors: Kheoruenromne Irb , Sharp W. E. , Gardner Leonard R.
Published: February 2008

The mean ratio of the link magnitude of drainage patterns on a small‐scale map to that of a large‐scale map is equal to twice the ratio of the map scales. This finding is confirmed by statistical testing of link magnitude data from a large number of maps of several different scales. The distribution of the observed link magnitude ratios is log normal, and the variance is independent of map scale ratio. These results can be partially explained by Shreve's (1974) theory of topologically random stream networks.
The different forms of moisture profile development during the redistribution of soil water after infiltration
Authors: Youngs E. G. , Poulovassilis A.
Published: February 2008

Two different forms of moisture profile development may occur during the redistribution of soil water after infiltration. In one the profile shape continues to be similar to that during the infiltration process, with a fairly uniform water content region near the soil surface above a steep wetting front, and the rate of redistribution is inversely related to the infiltration depth. In the other, water drains from near the surface to appear as a step in the moisture profile below the wetting front at the cessation of infiltration, and the rate of redistribution is directly related to infiltration depth. Classical theory of soil water movement is shown to account for both forms of moisture profile development, which depend on the moisture profile shape at the cessation of infiltration and on the soil water properties of the porous material. Experimental results of moisture profile development in a sand column illustrate how different profile forms develop as the depth of infiltration is increased and, by inclining the experimental column, how they depend on the relative importance of the soil water pressure head gradients compared with that of gravity.
Infiltration analysis and perturbation methods: 3. Vertical infiltration
Authors: Babu D. K.
Published: February 2008

Simple perturbation methods continue to yield good results in the solution of the problem of vertical infiltration of water into unsaturated soils. The initial approximation is valid for all times and gives useful information about important flow characteristics. The required computations are always direct and simple. Some numerical work pertaining to Yolo light clay is presented to exhibit the advantages, relevance, and simplicity of the present analysis compared to other existing works on this topic.
Metarationality in benefit‐cost analyses
Authors: Ragade R. K. , Hipel Keith W. , Unny T. E.
Published: February 2008

A type of benefit‐cost analysis which is capable of handling both quantitative and intangible benefits and costs is presented. It is possible for each interest group to assign values to benefits and costs according to what that group thinks is correct. Linguistic descriptions are sufficient for the intangibles. The method is based upon the theory of metarationality, and it is shown how pseudo‐Boolean functions can be used to define the concepts of metarationality and also record preferences of the parties involved in an analysis.
Major carbon 14 anomaly in a regional carbonate aquifer: Possible evidence for megascale channeling, South Central Great Basin
Authors: Winograd Isaac J. , Pearson F. J.
Published: February 2008

The carbon 14 content of groundwater at the center of a 16‐km‐long fault‐controlled spring line at Ash Meadows in south central Nevada is 5 times greater than that in water from other major springs along the lineament. The difference in carbon 14 stands in marked contrast to the near identity of all springwaters in alkalinity, pH, carbon 13, oxygen 18, deuterium, tritium, and other major and trace ions. Ten possible explanations of this major carbon 14 anomaly are evaluated by using all available chemical and isotopic data from basin‐wide wells and upland springs tapping the regional carbonate aquifer discharging at Ash Meadows. The four most plausible hypotheses require the presence of a major longitudinal heterogeneity in the distal portion of the groundwater basin to explain the anomaly. Flow channeling with an amplitude of at least 11 km is indicated. The simplifying assumption commonly used in simulation of basin‐wide flow through fractured or solution‐riddled aquifers, namely, that the aquifer is ‘homogenous in its heterogeneity,’ is not applicable to the dense fractured Paleozoic carbonate rocks comprising the Nevada aquifer; heterogeneities in this aquifer do not cancel each other areally.
Optimal long‐term control of a multipurpose reservoir with indirect users
Authors: Opricović Serafim , Djordjević Branislav
Published: February 2008

A new algorithm for optimal long‐term control of a multipurpose reservoir with direct and indirect users is described. (Indirect users are those who reuse water after some direct user, e.g., the hydro.) In such cases the usual dynamic programing algorithms cannot be used. We have developed a three‐level algorithm for solving such problems: At the first level, optimize the distribution of available water among time intervals; at the second level, allocate water to direct users in one time interval; at the third level, allocate water already used by direct users to indirect users further downstream. Dynamic programing is employed at all three levels, but the recurrence relations are developed in accordance with the decomposition of the control problem.
A hierarchy of response functions for groundwater management
Authors: Dreizin Yosef C. , Haimes Yacov Y.
Published: February 2008

The physical system this paper deals with is a river basin with multiunit aquifers and interconnected streams. The problem was how to model this complex system mathematically and then to represent it in terms of its response to stress in the form of pumpage and recharge. The system responds to pumpage in two ways: as drawdown or as flow between streams and aquifers. A hierarchy of linear mathematical models for a large‐scale physical system response to stress was developed. For the system response an explicit mathematical expression was used to couple the physical system with the formulation of a management model. The models developed in this paper were successfully tested on a case study of the Fairfield‐New Baltimore area at the lower part of the Great Miami River in southwestern Ohio.
Quality characteristics of urban storm water in Sydney, Australia
Authors: Cordery Ian
Published: February 2008

Storm water samples collected from three urban watersheds in Sydney, Australia, show that in separately sewered areas the surface runoff has a greater concentration and carries a greater total load of pollutants than effluent from secondary sewage treatment plants. Pollution and nutrient indicators are highly concentrated in the ‘first flush’ at the start of urban storm runoff, but these concentrations fall rapidly to quite low levels during the passage of each flood. An important exception to this trend is phosphate. The phosphate concentration remains approximately constant during each flood. Whenever the discharge increases sharply, the concentrations of suspended solids and phosphate increase slightly. However, the concentrations of BOD and ammonia do not usually increase after the first flush unless a later increase in discharge is extremely rapid. Fecal coliform concentrations in flood flows are usually about 2 orders of magnitude less than those for raw sewage.
Snowmelt: A two‐dimensional turbulent diffusion model
Authors: Weisman Richard N.
Published: February 2008

The melt from a ripe snowpack due to sensible and latent heat flux is considered. The problem is two‐ dimensional; the snow field has a well‐defined leading edge. The equations that describe the airflow over the snow are the conservation of momentum, sensible heat, and water vapor. The turbulent diffusion is formulated by semi‐empirical turbulence theory. The solution shows the manner in which the point melt varies downwind from the leading edge and the average melt varies with the fetch of the snowpack for varying degrees of atmospheric stability conditions. The results indicate that a reasonably accurate estimate of total melt can be achieved by using the one‐dimensional formulae with temperature, humidity, and velocity measurements taken over the central part of the snow field.
The design of a system for collecting leachate from a lined landfill site
Authors: Wong J.
Published: February 2008

A system for collecting leachate at the bottom of a landfill site is conceptualized, and the design parameters for the system are specified. The core of the system is a sloped low‐permeability earthen liner that deflects downward infiltration to a series of collector tiles. Equations are derived that describe the drainage and leakage processes on top of the leaky liner. A simple graphical procedure is developed to quantitatively evaluate the collection efficiency of the system. With this procedure, some implications of various options available to landfill design are examined. Finally, the main assumptions used in the model are examined critically to explain qualitatively the limitations of the model.
Determination of regional evapotranspiration from upper air meteorological data
Authors: Mawdsley John A. , Brutsaert Wilfried
Published: February 2008

A procedure, recently proposed by the authors to calculate actual evapotranspiration on the basis of parameterization of the atmospheric boundary layer, was applied for the period April through November 1969–1972 with upper air (‘rawinsonde’) meteorological data from Omaha, Nebraska. The accuracy of the 1‐day, 3‐day, weekly, and monthly evapotranspiration totals was assessed by comparing them to evapotranspiration data estimated by a suitable adjustment of potential evapotranspiration from a nearby catchment in the Treynor basins. Several alternative methods for determining the height of the boundary layer and the wind speed at the top of the boundary layer were used; as a result, seven variations of the basic procedure were tested. The similarity functions for water vapor D were found to be smaller than the corresponding functions for sensible heat C and not equal as was previously assumed. Difficulties were encountered, since published upper air humidity data were in error; nevertheless, the method was reasonably successful on a monthly basis with a correlation coefficient of the order of 0.83 but far less so on a daily basis. The recommended version of the method uses the height of the temperature inversion as an estimate of the boundary layer height and the measured wind as the estimate of the wind speed at the top of the boundary layer.
On determining distances through stream networks
Authors: Ferguson R. I.
Published: February 2008

Simple methods are described for calculating the magnitudes and lengths of all links in a stream network and their topologic and geometric distances from the outlet, starting from the binary topologic string and digitized junction and source coordinates. By processing the complete network in reverse maze order, successive stages of the analysis yield the properties of all subnets.
Similarity solutions for convection of groundwater adjacent to horizontal impermeable surfaces with axisymmetric temperature distribution
Authors: Cheng Ping , Chau W. C.
Published: February 2008

The axisymmetric buoyancy‐induced groundwater flow adjacent to horizontal impermeable surfaces, wall temperature being a power function of radius, is discussed in this paper. With the boundary layer simplifications the governing nonlinear partial differential equations can be transformed into a coupled pair of nonlinear ordinary differential equations with two‐point boundary conditions that can be integrated numerically by established techniques. Simple algebraic expressions for boundary layer thickness and heat transfer rate are obtained. Applications to free convective flow in a liquid‐dominated geothermal system at high Rayleigh numbers are discussed.
Water shortage in Israel: Long‐run policy for the farm sector
Authors: Gisser Micha , Pohoryles Samuel
Published: February 2008

Israel faces a situation of a limited amount of water supply and increasing demands. Since agriculture uses a large fraction of the water available in this country, one potential policy is to reduce allocations of water to agriculture in order to permit the growth of use in other sectors. Estimates of the total loss in income to agriculture from reduction in current allocations are made by using a linear programing model. These are to be taken as guideline estimates only.
Evaporation in high latitudes
Authors: Rouse Wayne R. , Mills Peter F. , Stewart Robert B.
Published: February 2008

A simplified form of the equilibrium model of evaporation predicts evaporation from six subarctic and tundra surfaces with an accuracy of 8%. Input data to the model are net radiation, screen air temperature, and an evaporability factor characteristic of the surface. The radiation and energy balances of the six surfaces are compared.
Price variable in residential water demand models
Authors: Gibbs Kenneth C.
Published: February 2008

There have been inconsistencies in past residential water demand studies concerning the specification of the relevant price variable. Both average and marginal price have been used. Households faced with the decision to expand (or contract) their water consumption are responsive to the additional cost (or savings) involved with this decision. The appropriate measure of this price is marginal price, not average price. Data were gathered from a large metropolitan area, Miami, Florida, to illustrate the divergence in estimation from two demand models, identically specified, except for the price variable. One utilized marginal price, the other average price. Predictions of consumption varied from 22 to 107% between the two models. The average price model significantly overestimated the response of consumption to price and income changes, a result worthy of consideration.
Reservoir storage with dependent, periodic net inputs
Authors: Troutman Brent M.
Published: February 2008

Let Rn denote the range of cumulative sums of the net inputs to a reservoir during n time intervals. For periodic net inputs possessing a wide variety of covariance structures, the asymptotic behavior of Rn is given by limn→∞ P[Rn/γn½ ≤ r] = FR(r), where γ is a function of the dependence and periodicity assumptions on the net inputs and FR is the cumulative distribution function of the range of a standard Brownian motion process. Analogous results hold for the adjusted range, rescaled adjusted range, and maximum deficit. (The last quantity is the storage obtained upon application of the sequent peak algorithm.) As previous authors have argued, the n½ behavior of the rescaled adjusted range is not inconsistent with H. E. Hurst's empirical findings if it is assumed that the so‐called Hurst phenomenon is a preasymptotic property of reservoir behavior. Useful representations for the parameter γ may be obtained for many of the net input sequences employed in hydrologic modeling, such as mth‐order autoregressive (stationary or periodic) and log autoregressive processes.
Ralston Creek hourly precipitation model
Authors: Croley Thomas E. , Eli Robert N. , Cryer Jonathan D.
Published: February 2008

A stochastic hourly precipitation model is developed by using the Iowa City‐Ralston Creek hourly precipitation record of 33 years length. Six divisions of the year are used to account for seasonal nonstationarity. Related wet time intervals, corresponding to storm events, are scheduled by an exponentially distributed interarrival time model. Intrastorm structure is described in terms of ‘storm segments,’ corresponding to the passage of a storm rainfall cell or a group of cells. It is found that the location in time and the duration of storm segments can be adequately modeled by independent random variables, thus avoiding traditional computation difficulties in modeling the persistence effects encountered in hourly data. Observed ‘persistence’ is preserved, since persistence results from the clustering of wet hours and the clustering of dry hours. The intensity and distribution of precipitation within storm segments are modeled by fitted log normal intensity probability distributions and by cataloging sample storm segment shapes. Generated data analysis indicates that very precise precipitation modeling and extremely high speed data generation result.
Atmospheric nitrogen and phosphorus loading to Harp Lake, Ontario, Canada
Authors: Nicholls Kenneth H. , Cox Charles M.
Published: February 2008

Nitrogen and phosphorus in precipitation and dry fallout (aeolian sources), as well as the pH of rainfall, were measured over Harp Lake in Ontario during 1974. Weighted mean concentrations of total N and total P during the ice‐free period of collection were 1.91 mg N/l and 0.105 mg P/l. Winter concentrations of total N were similar, but total P concentrations were much lower, averaging 0.013 mg/l in fresh snow. Total atmospheric loading of P to the lake was 74.4 mg P/m2 yr, and the total N loading was 1600 mg N/m2 yr. About 52%, or 39.0 mg P/m2 yr, of the total P loading from the atmosphere was total dissolved P (0.22‐µm filtrate), and 28%, or 20.6 mg P/m2 yr, of the total P loading was dissolved reactive P (‘Orthophosphate’ P). Dissolved inorganic N loading at 1010 mg N/m2yr comprised about 63% of the total N loading from the atmosphere. Pollen, from a variety of trees surrounding the lake, contributed about 20% of the total P input. The pH of rainfall samples ranged from 3.2 to 5.1 with a median value of 3.9 (n = 14).
Water pressure in ripe snowpacks
Authors: Wankiewicz Anthony
Published: February 2008

The water pressure regime of a quasi steadily melting homogeneous and isotropic snowpack is derived from Darcy's equation and from an experimental determination of the permeability‐pressure relation for snow. The derivation demonstrates that at a given melt rate, (1) significant water pressure gradients are confined to the base of the snowpack and (2) the snow water pressure at higher levels is independent of depth and equal to a characteristic value called the gravity flow pressure, which is a function of the melt rate and wetting history of the snow. Simple and inexpensive tensiometers were used to measure the water pressure variations in a deep snowpack. Diurnal pressure changes were found to be about 300 N m−2 in amplitude within the ripe snow. Layering resulted in a scattering of the water pressures along the vertical direction. Such simple tensiometer measurements can now be used with the above derivation to provide field measurements of the permeability of different types of snow.
Climate, soil, and vegetation: 4. The expected value of annual evapotranspiration
Authors: Eagleson Peter S.
Published: February 2008

The depth of interstorm evapotranspiration from natural surfaces is composed (by proportion to vegetal canopy density) of evaporation from bare soil and transpiration from vegetation. The former is obtained in terms of random variables describing initial soil moisture, time between storms, and potential rate of evapotranspiration from an exfiltration analogy to the Philip infiltration equation modified to incorporate moisture extraction by plant roots. The latter is assumed to occur at the potential rate for natural vegetal systems. In a zeroth‐order approximation the initial soil moisture is fixed at its climatic space and time average whereby using an exponential distribution of time between storms and a constant potential rate of evapotranspiration the expected value of interstorm evapotranspiration is derived. This mean value is used to obtain the annual average point evapotranspiration as a fraction of the potential value and as a function of dimensionless parameters defining the climate‐soil‐vegetation system.
Some comparisons of flood statistics in real and log space
Authors: Landwehr J. Maciunas , Matalas N. C. , Wallis J. R.
Published: February 2008

Some statistics of historical and simulated flood sequences were examined in real and log space. It was found that several statistical properties of floods in real space could not be inferred from those in log space without extensive knowledge of the distribution of floods in real space as well as information about their sampling characteristics. It is shown that the construction and use of regional skew maps in log space are most likely counterproductive.
Application of decision theory to salmon management
Authors: Sheehan S. W. , Russell S. O.
Published: February 2008

Bayesian decision theory provides concepts that seem ideally suited to many renewable resource management problems. A procedure for applying the concepts to salmon management in real time is illustrated with an example from the Skeena River fishery in Northern British Columbia, Canada. The decision in question is the escapement to allow for spawning purposes in a particular year. The procedure involves determining a probabilistic relationship between the escapement in one year and the number of adults returning in the cycle year 4 years later, defining a utility curve for the catch, forecasting the number of salmon expected to return in the current year, and computing the escapement with the maximum expected utility. Discussion indicates areas where further work is needed and also other possible applications of the procedure.
Relationship between alluvial soils and flooding in the Piedmont lowland of southeastern Pennsylvania
Authors: Price Helen , Johnson Arthur
Published: February 2008

Regressions of 50‐ and 100‐year synthetic flood widths on widths of alluvial soils bordering the stream were computed with confidence intervals for data from streams in the Piedmont Lowland of southeastern Pennsylvania. These intervals were too wide to recommend use of alluvial soils in floodplain zoning in this gently rolling terrain. A rule of thumb of 2½ times the alluvial soils width was suggested for safe location of land uses for which flooding would be intolerable. Data for one of the minor soils indicated that some soils may delineate flood hazard areas better than others, but too few data were available for complete analysis.
The generalization of Darcy's Law for nonuniform flows
Authors: Dagan G.
Published: February 2008

A generalized Darcy's law for nonuniform flows in which the pressure gradient depends on the velocity and its derivatives is adopted. The permeability coefficient, as well as a new coefficient, is investigated with the aid of the averaged dissipation equation. The additional coefficient appearing in the generalized law is estimated with the aid of a cell model, and the generalized law is employed in order to solve a few problems (Couette flow past a porous boundary, refraction at the boundary between two porous samples, and flow around a thin partition). Deviations from Darcy's law are found to be confined to thin layers near the medium boundaries.
Unsteady groundwater flow on sloping bedrock
Authors: Frangakis C. N. , Tzimopoulos C.
Published: February 2008

A numerical model based on the equation describing the unsteady groundwater flow on impervious sloping bedrock has been herewith formulated. The case which has been studied concerns the groundwater flow from one canal to another with a sudden rising of the canal level as an upstream boundary condition, while the downstream level remains constant. Initially, at time t = 0, both levels are equal. The numerical model uses the finite element technique with Galerkin's method. The stability and accuracy of the method have been proven by comparison of numerical results with the Crank‐Nicolson scheme. The algorithm developed for the finite element technique gives the same results as the one for the finite difference scheme. The effect of inclination of lower impervious boundary on outflow rate has been studied.
Wastewater treatment capacity expansion with time‐varying assimilative constraints
Authors: Baziw John , Scherer Charles R.
Published: February 2008

Optimal wastewater plant capacity expansion is reexamined for the general case where effluent receiving water standards vary with time. A deterministic dynamic programing framework is used to find cost‐minimizing expansion plans for wastewater treatment when hydraulic demand is assumed known and nondecreasing with time. The effect of discount rate, initial hydraulic capacity, and initial plant pollutant removal rate on expansion plan is investigated. Results show time‐variable effluent receiving standards can significantly influence cost‐minimizing expansion plans.
Unsteady interzonal free surface flow in porous media
Authors: Liggett James A. , Liu Philip L.‐F.
Published: February 2008

The behavior of the free water surface at discontinuities in permeability for steady flow has been known for more than 40 years and has been used in numerical solutions and flow net sketching. The present paper extends that analysis to unsteady flow, primarily for use in numerical solutions. For a rising free surface the diffraction between zones is given in graphical form. For a falling free surface (almost) no diffraction solution exists and the free surface is either horizontal or tangent to the line of discontinuity. However, sharp curvatures may occur in the vicinity of a permeability change so care must be exercised in extrapolating free surface slopes to neighboring regions.