bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal Timing, Sequencing, and Sizing of Multiple Reservoir Surface Water Supply Facilities
Authors: Becker Leonard , Yeh William W‐G.
Published: February 2008

This paper outlines a method whereby the timing, sequencing, and sizing of a water supply development is validly performed. The method takes care of the vital fact that although it is firm water that is demanded or sold, it is reservoir capacity at a particular site that is costed, and the two are not simply related, nor is the relationship independent of previously constructed reservoirs and the stream‐reservoir configuration. A feature of this method is a simple firm water determination concept that is applicable to any steam‐reservoir configuration and that uses rational and reasonable operating rules at each basic time period for the calculations of reservoir storage changes resulting from excess or deficit streamflows relative to demand in those periods. Details of interchanges of water between reservoirs are not relevant to this concept. Streamflows are taken to be the subnormal flow hydrographs that would correspond to a critical period analysis method, but no advantage is taken of any supposed knowledge about future flows.
Simulation of Gamma‐Distributed First‐Order Markov Chain
Authors: Klemeš V. , Borůvka L.
Published: February 2008

A first‐order Gaussian Markov chain is used to produce a Markovian series of numbers uniformly distributed in the interval (0, 1), which in turn is used for generating a first‐order Markov chain with a gamma‐type marginal distribution.
Response and Recovery of a Piedmont Watershed From Tropical Storm Agnes, June 1972
Authors: Costa John E.
Published: February 2008

Tropical storm Agnes generated flooding with a recurrence interval much greater than 100 years in a Piedmont watershed: 633 cfs/mi2 from 60 mi2. Deposits on floodplains were scarce and could be mapped as sand and gravel and as sand. Deposition occurred where tributaries joined the main channel, across meander bends, and below valley constrictions such as roads and bridges. Despite the magnitude of the rainfall and flooding there were no slope failures in the basin. The only modifications to the watershed were observed in the lowlands along the main channels. Channel widening was the most spectacular modification. Within 1 year of the flood, channel cross sections were well along recovery toward pre‐Agnes dimensions. Meandering reaches of the channel recover faster than straight reaches. The Agnes flood is nearly the largest ever reported from a Piedmont watershed of this size. Large floods in the Piedmont apparently play a minor role in shaping the landscape, whereas large floods in the Blue Ridge/Valley and Ridge and Appalachian Plateau provinces, and consequent slope failure, are very active landscaping agents.
A numerical model based on coupled one‐dimensional Richards and Boussinesq equations
Authors: Pikul Mary F. , Street Robert L. , Remson Irwin
Published: February 2008

An approximate numerical method to solve transient two‐dimensional unsaturated‐saturated subsurface flow problems is presented. Several one‐dimensional vertical unsaturated column models are linked to a one‐dimensional saturated flow model. The Dupuit‐Forchheimer assumptions are used for the saturated flow, and the unsaturated flow is assumed to be strictly vertical. The systems are linked because solutions of the equation governing unsaturated flow determine recharge and storage information used to solve the equation governing saturated flow. In addition, the position of the water table locates the lower boundaries of the unsaturated models. The solution of a test problem using a linked model is compared with results from a rigorous two‐dimensional model. The comparison is good at early times when recharge to the water table is small but poor at later times when recharge increases. Applications are then made to field‐size problems. Results compare closely with an actual groundwater hydrograph. In addition, a linked model is used to show that in a specific humid climate watershed the type of vegetation does not significantly affect the groundwater regimen, whereas in a given arid climate watershed the type of vegetation would determine whether groundwater recharge occurred. For field‐size problems where water table movement is relatively small, where the Dupuit‐Forchheimer assumptions are valid, and where lateral unsaturated flow is not important, the linked model offers an efficient approximate way to solve unsaturated‐saturated flow problems.
Price responsiveness of the industrial demand for water
Authors: De Rooy Jacob
Published: February 2008

In order to determine the sensitivity of the industrial demand for water to changes in price a simple set of demand equations is formulated and tested with data on water use by 30 large plants. Results suggest that firms do adjust quantities demanded in response to even small price changes. Demand is also significantly affected by changes in output, by technological improvements, and by employment.
Mathematical simulation of the subsidence of Venice: 2. Results
Authors: Gambolati Giuseppe , Gatto Paolo , Freeze R. Allan
Published: February 2008

Land subsidence at Venice is the result of aquitard compaction caused by extensive groundwater withdrawals from the unconsolidated Quaternary aquifer‐aquitard system that underlies the Venetian lagoon. A two‐step mathematical model consisting of a regional hydrologic model and a local subsidence model has been used to analyze the system. Results show that the total subsidence over the period 1930–1973 has been about 15 cm. Geodetic records, which cover only the latter portion of this period, provide documentary evidence for a 10‐cm subsidence during 1952–1969. Simulations of the past used to calibrate the model show that extractions from a single large well in the Tronchetto region of Venice have exerted a small but measurable influence on the subsidence, but the main responsibility for subsidence at Venice must be placed on the heavy industrial pumpage at the mainland port of Marghera. Predictive simulations show that any changes in the withdrawal rate at Marghera will tend to propagate their effects to Venice in a relatively short time, and there will be little delay between the occurrence of head declines at Venice and the resulting subsidence. If withdrawals at Tronchetto and Marghera are kept constant in the future as they have been since 1969, about 3 cm of further subsidence can be expected. Subsidence could be arrested at its present level by a shutdown of the Tronchetto well and a reduction of Marghera pumpage to three quarters of its present value. Complete cessation of all pumping would provide a modest rebound of about 2 cm over the next 25 years. The results of this study are based on a model that was limited by the requirements of radial symmetry and a calibration that was hampered by the sparseness of the available data. The subsidence situation at Venice should remain under continued evaluation as further data become available and more complex models become feasible.
Analysis of unsteady flow toward an artesian well by three‐dimensional finite elements
Authors: Huang Yang H. , Sonnenfeld Stephen L.
Published: February 2008

A numerical method based on three‐dimensional finite elements is presented for determining the unsteady drawdown around an artesian well. The uniqueness of the method lies in the use of cylindrical elements, the stiffness matrix of which can be easily derived. The method was programed for a high‐speed computer, and the capability of the computer program is described. A comparison between the finite element and the exact analytical solutions for some simple cases indicates that the use of cylindrical elements yields accurate results. An example is given to illustrate the application of the method to non‐homogeneous and asymmetric aquifers where the hydrogeologic boundaries can be approximated by the cylindrical elements.
Generalized skew coefficients of annual floods in the United States and their application
Authors: Hardison Clayton H.
Published: February 2008

Generalized skew coefficients for use in defining flood‐frequency curves that follow log Pearson type 3 distributions are shown by isopleths on a map of conterminous United States. The generalized logarithmic skew coefficients range from 0.6 along the eastern seaboard to −0.5 in Indiana and Illinois. West of the one‐hundredth meridian the coefficients range from −0.3 to 0.2 except for a small area in Nebraska where the generalized skew goes as high as 0.4. The validity of the map values is verified by a split‐sampling procedure. In the west the discharge of 50‐ and 100‐yr peaks computed by using map values of skew is more accurate than that computed by using the observed skew of a sample of 30 annual peaks. East of the Mississippi River the accuracy is even higher and approaches the equivalent of 60 annual peaks along the east coast. An equation gives the adjustment by which a T‐yr peak computed by using map skew would have to be increased to give a discharge that has an average exceedance probability equal to 1/T.
Adjustment of river channel capacity downstream from a reservoir
Authors: Gregory K. J. , Park C.
Published: February 2008

The construction of a reservoir may provide an opportunity to identify the way in which a changed pattern of river discharge below a dam results in an adjusted channel capacity. This is tested in the basin of the River Tone, Somerset, by comparing channel capacity above and below the Clatworthy reservoir, constructed in 1959. At a number of sites below the dam the channel cross section is multiple in form, the upper element represents the bank‐full stage prior to dam construction, and the lower element is the contemporary bank‐full level. The reduction of channel capacity downstream from the reservoir persists for a distance of 11 km until the catchment area contributing to the river is at least 4 times that draining to the reservoir. Peak discharge below the dam is deduced to be approximately 40% of the value that obtained prior to reservoir construction.
The Oxygen Sag Equation: New properties and a linear equation for the critical deficit
Authors: Arbabi Mansur , Elzinga Jack , ReVelle Charles
Published: February 2008

In this paper some newly discovered properties of the Streeter‐Phelps oxygen sag equation are examined. The convexity of the critical dissolved oxygen (DO) deficit is established, and it is shown that the critical DO deficit can be represented by a conical surface. By using these properties it is shown how to approximate with a high degree of accuracy the critical deficit as a linear function of initial BOD loading and initial oxygen deficit. The linear approximating equation will find use in mathematical programing formulations of water quality management problems.
Modification of routed streamflow by channel loss and base flow
Authors: Moench Allen F. , Sauer Vernon B. , Jennings Marshall E.
Published: February 2008

The convolution integral is used to compute continuous variations in channel loss and base flow that result from a reservoir release on the North Canadian River in central Oklahoma. The open channel flow hydrograph is routed by using the unit response method and then modified for interaction with the aquifer. Stream losses and gains are evaluated from the arbitrary fluctuations in stream stage by using average values of aquifer parameters. In spite of gross simplification pertaining to the nature of the groundwater system, good agreement with the actual flow hydrograph is obtained.
Statistical analysis of water temperature residuals
Authors: Gillett Billy E. , Long Leland L.
Published: February 2008

Water temperature residuals, which are taken as the difference between the daily average water temperature (Missouri River, Boonville, Missouri) and the Fourier series regression fit to the data points, are analyzed. A 1‐yr record length is used as a base period. The Kolmogorov‐Smirnov test is used to determine, for a given number of extracted harmonics, the sample size required to yield a set of normal random variates with mean zero. It is also shown that with only the fundamental harmonic removed, a sample size of at least 180 is required to yield a sample average residual of less than 0.2°F. When the fundamental and higher order harmonics are removed, this sample size is reduced considerably.
On thermal stratification in large bodies of water
Authors: Rahman M. , Marcotte N.
Published: February 2008

A method of predicting water temperature in large bodies of water has been presented in this paper. The vertical water column is subdivided into two layers: an isothermal surface layer and a temperature‐stratified diffusion layer. Meteorological data, either real or imposed, are used for calculating the variation of water temperature with time in the surface layer utilizing the thermal budget method. Then in the diffusion layer the temperature profiles are obtained by solving the time‐dependent energy equation by the similarity technique with variable density, conductivity, and diffusivity and zero velocity. Calculated water temperatures are compared with the measured values. The comparison shows favorable agreement.
Optimal cost design of branched sewer systems
Authors: Mays Larry W. , Yen Ben Chie
Published: February 2008

Techniques using dynamic programing (DP) and discrete differential dynamic programing (DDDP) to achieve optimal cost design of pipe sizes and elevations of branched sewer systems have been developed and demonstrated by an example. The branched system is decomposed into equivalent serial subsystems, which are then solved in sequence. DDDP requires less computer time than DP, although it cannot guarantee global optimization. Major factors affecting the efficiency in using DDDP are the location and width of the initial trial trajectory corridor, the number of states (lattice points) used, and the reduction rate of the state increment during iterations.
On the efficient allocation of environmental assimilative capacity: The case of thermal emissions to a large body of water
Authors: Scherer Charles R.
Published: February 2008

This report considers the economically efficient level of environmental assimilative capacity in the case of thermal electric rejected heat discharges to large lakes subject to temperature standards. A mathematical model relating heated effluent flow rate and ‘near‐field’ temperature is used to determine maximum diffuser port size. Diffusor costs are developed as a function of discharge velocity, port size being given. Cooling tower costs are also developed for comparison with diffusor costs in selecting an optimal level of thermal assimilative capacity. The relationship between this selection process and optimal power plant siting models is outlined. It is shown that arbitrarily fixing discharge velocity at some ‘practical’ level will tend to bias the results of these siting models toward overly conservative use of thermal assimilative capacity. That is, available capacity will not be fully exploited, and the cost of a given level of power output will be greater than is necessary.
Water losses from an irrigated soybean field by deep percolation and evapotranspiration
Authors: Carvallo H. O. , Cassel D. K. , Bauer A.
Published: February 2008

Soil water flux below the root zone of a soybean crop was measured in the field at Oakes, North Dakota, during the crop season in 1972 for four water treatments. Amounts of 0, 30.6, 38.1, and 47.0 cm of water were applied in addition to the 19.5‐cm rainfall occurring during the growing season to treatments W‐1, W‐2, W‐3, and W‐4, respectively. Specific in situ unsaturated hydraulic conductivity for each plot of the Maddock sandy loam soil and hydraulic gradients measured with tensiometers in the field during the growing season were used to compute the soil water flux. Knowledge of the amount of water applied by irrigation and rainfall, of the water loss to deep percolation, and of the changes in soil water content in the soil profile permitted estimation of evapotranspiration from the soil‐plant systems.

This summary and the entire article are available on microfiche. Order as document W‐75‐001 from American Geophysical Union, 1909 K Street, N.W., Washington, D.C. 20006. Payment ($1.00 must accompany order.
Hypolimnetic oxygenation using liquid oxygen
Authors: Fast Arlo W. , Overholtz William J. , Tubb Richard A.
Published: February 2008

A new system of hypolimnetic oxygenation called side stream pumping (SSP) is described. The SSP system uses liquid oxygen and a conventional water pump, whereas most other hypolimnetic oxygenation systems use compressed air and a special aeration chamber. The SSP system was tested in Ottoville Quarry, Ottoville, Ohio, during the summer of 1973. Hypolimnetic oxygen concentrations increased from less than 0.5 mg/1 to over 8.0 mg/1 during 2 months of operation, and thermal stratification was maintained. These improvements created a suitable habitat for cold‐water fish, but care must be exercised in the use of the SSP system to avoid potential problems with high, free carbon dioxide concentrations.
Transient flow routing in channel networks
Authors: Wood Eric F. , Harley Brendan M. , Perkins Frank E.
Published: February 2008

The formulation of a mathematical model to predict transient flows in hydraulic networks is presented. The network formulation consists of breaking the network up into a series of connected reaches; reducing the finite difference equations for each reach into two ‘reach’ equations; forming an exterior matrix consisting of the reach equations, external boundary conditions, and interior compatibility conditions; solving the external matrix for the end values of discharge and water surface elevation for all reaches; and back‐substituting for all interior values. Examples presented include the James River, USA, estuary model (24 nodes and 26 reaches), the Cork Harbor, Ireland, estuary (13‐reach double‐looped network), and the Rio Bayamon basin, Puerto Rico. Results are very satisfactory when they are compared to known data.
Infiltration and runoff for small field plots under constant intensity rainfall
Authors: Swartzendruber D. , Hillel D.
Published: February 2008

A relatively simple infiltration equation is used to express the family of infiltration flux time curves that occur under constant rate water application (sprinkling or rain) from the time that excess water appears at the soil surface. The equation is easily integrated for cumulative water excess as a function of time, which in turn allows taking into account a simplified static surface storage volume to calculate cumulative water runoff. The runoff equation so obtained was tested by means of a sprinkling infiltrometer used on plots of 1 m2 and was found to express with good accuracy the measured cumulative plot runoff as a function of time. The field data, taken with a modified Purdue‐Wisconsin sprinkling infiltrometer on Rehovot loamy sand, were then utilized successfully for obtaining the ultimate steady infiltration flux, even when the period of measuring transient runoff was less than 1 hour and the total runoff less than 1 cm of water. The value of steady flux so obtained was in good agreement with that found under the condition of continuous ponding of water on the soil surface.
Bayesian inference and decision making for extreme hydrologic events
Authors: Wood Eric F. , Rodríguez‐Iturbe Ignacio
Published: February 2008

Hydrologic decision making usually occurs in an uncertain world and should combine inferences about uncertain outcomes with the decision makers’ preferences toward these outcomes. The decisions associated with flood protection are considered in detail where there exists uncertainty in the frequency of future flood discharges. Procedures are developed for analyzing and accounting for both statistical uncertainty of competing flood frequency models and statistical parameter uncertainty for the individual models. Inferences about flood frequency are combined with a decision model for which the decision rule is the maximization of expected monetary benefits. A case study to determine the optimal size of local flood protection by using prior information from a regional regression model, historical data, and realistic flood cost and damage functions is presented.
Parameters for estimating annual runoff and soil loss from agricultural lands in Rhodesia
Authors: Elwell H. A. , Stocking M. A.
Published: February 2008

Cumulative values of rainfall energy, momentum, and precipitation depth were investigated as predictors of annual soil loss and runoff from selected arable and grazing land field trial plots. Energy parameters were the most accurate predictors of soil loss from bare soils, explaining 96.4% of the variation in results from a clay loam and 80.0% from a sandy soil. However, little accuracy was lost by adopting the more practical precipitation depth parameters. There was little to choose between momentum, energy, and precipitation depth parameters as predictors of soil loss from the vegetated plots or as predictors of runoff from both bare and vegetated conditions. Consequently, precipitation depth parameters were selected as being the most practical for soil loss and runoff estimation under the conditions investigated. Percentage vegetal cover was shown to be an additional important variable on grassland.
The Log Pearson type 3 distribution and its application in hydrology
Authors: Bobée Bernard
Published: February 2008

A mathematical and statistical study which shows the flexibility and limitations of the log Pearson type 3 distribution is carried out. The results obtained indicate the various forms of density function and relationships that exist between distribution parameters and moments, coefficient of variation, and coefficient of skewness. The method of fitting proposed by the Hydrology Committee of the Water Resources Council is compared with a new method which instead of using moments of the logarithmic values retains the moments of the original data. In the case of events with a large return period the results obtained by the two methods may deviate appreciably, and because in the proposed method the same weight is given to each of the observed values, it will result in a better fit of the data.
Comment upon multivariate synthetic hydrology
Authors: Finzi G. , Todini E. , Wallis J. R.
Published: February 2008

O'Connell has proposed a correction to Young and Pisano's numerical multisite package (NMP) which we believe is necessary but insufficient to make the computer coding reproduce the desired Matalas algorithm for Markovian synthetic flows. In addition, we believe that the sequences generated by even a corrected computer program may not always be adequate for reservoir optimization studies.
A combined model of water table and river stage evolution
Authors: Morel‐Seytoux H. J.
Published: February 2008

An integral equation is derived which completely characterizes the interaction between a stream and the alluvial aquifer. Expressed in finite difference form, the equation is of great practical utility to solve pure flooding problems (i.e., negligible effect of pumping on river flows) as it relates river stages to return flows, pure conjunctive use of surface water and groundwater problems (i.e., negligible river stage fluctuations) as it relates return flows to pumping rates, or to solve composite problems. The numerical procedures to calculate the response function coefficients in terms of the physical characteristics of the system are given in detail.
The development of water multiplier impacts from input‐output analysis: An empirical example from Boulder, Larimer, and Weld Counties, Colorado
Authors: Gray S. L. , McKean J. R.
Published: February 2008

The relationship between economic activity in a regional economy and water intake and consumptive use requirements is investigated by using the Leontief model. Estimates of direct and indirect water requirements for the regional economy are developed and are applied to three distinct planning questions: estimated aggregate water use in the regional economy, estimated sector by sector water requirements in response to total projected changes in final demands, and estimated changes in water requirements in the regional economy given a change in a single sector's deliveries to final demand.
Fine‐scale time variations of rainfall in western Oregon
Authors: Trump C. L. , Elliott W. P.
Published: February 2008

One‐minute rain rates were measured at three stations on a line running inland from the coast across a low mountain range during a winter rainy season. The averages of three nondimensional variability statistics were significantly greater on the coast than inland. Rain rate distributions showed that a greater portion of the rain fell at higher rates on the coast, and autocorrelation analyses showed that the rainfall was less persistent on the coast than inland. Oregon results were compared with similar results concerning Illinois summer convective rainfall. Even though the Illinois rainfall was distinctly more intense and less persistent than the Oregon rainfall, the relative variabilities were surprisingly similar. The logarithm of the total rain falling at rates greater than a given rate was found to be a linear function of that rate.
A note on computing finite difference interblock transmissivities
Authors: Appel Charles A.
Published: February 2008

A formula is developed for computing interblock transmissivities for the case where the transmissivity varies more or less linearly between block centers. The error in interblock flow rates resulting at steady state conditions, when either the arithmetic or harmonic mean of (T/Δx) is used for adjacent blocks for the interblock transmissivity, can be significant for some variations of block size and transmissivity.
Unsteady groundwater flow beneath strip oceanic islands
Authors: Anderson M. P.
Published: February 2008

Two one‐dimensional models based on the Dupuit‐Forchheimer assumptions to simulate flow beneath strip oceanic islands are presented. A model which is here designated the continuously moving interface (CMI) model is solved by finite differences. The solution agrees well with an analytical solution for a particular case given by Collins (1976). Because of its long response time the CMI model is not able to simulate short‐term fluctuations in water level in a well located on the South Fork of Long Island, New York. A second model, designated the delayed interface response (DIR) model, can reproduce the average hydrograph of the well and the decline in water level during most of an extended drought. However, because the model requires discontinuous movement of the interface between freshwater and salt water, some error is introduced into the solutions. The DIR model is used to predict the response of water levels to modifications in recharge patterns on the South Fork of Long Island.
Modeling of unsteady temperature distribution in rivers with thermal discharges
Authors: Hills R. G. , Viskanta R.
Published: February 2008

Analysis is presented for predicting unsteady temperature distribution in a channel simulating a river. The effects of thermal discharges, meteorological conditions, solar and atmospheric radiation and channel parameters on the thermal structure of a river are analyzed and discussed by utilizing an analytical model for the unsteady three‐dimensional temperature distribution in the far field of a thermally stratified channel. The effects of thermal start‐up, discharge temperature level, discharge location, river flow velocity, and others are investigated. The results show that the greater the temperature excess above the ambient at the discharge, the greater downstream distance is needed to reach a fully mixed condition because of the suppressive effect of stratification on the turbulent mixing. The greater surface temperatures associated with thermally stratified flow result in increased heat dissipation and water evaporation from the surface.
A climatonomic study of the Lake Ontario drainage basin
Authors: Granger Orman
Published: February 2008

An evapotranspiration climatonomy model (Lettau and Baradas, 1973) designed to compute monthly runoff, actual evapotranspiration, exchangeable moisture level, and stored moisture change, and incorporating seasonally varying parameter values was applied to the Lake Ontario drainage basin and to subbasins within it. The model was refined and improved by using a ‘direct search’ optimization technique (Rosenbrock, 1960) to obtain monthly values of the set of prescribed parameters. The parameters were calibrated using data for 1969–1971 inclusive and for long‐term means. They were then applied to relevant 1972 data as an independent test of the validity of the model. The results were consistent and reasonably reliable by comparison with others. The parameter values are physically justifiable and in accord with comparable parameter values reported in the literature. Computed monthly runoffs are within 1.4% of observed streamflow in the unregulated subbasins and within 6.0% in one that is regulated. For the Lake Ontario basin as a whole, computed monthly runoff is within 7.0% of measured outflow adjusted for lake level changes. The agreement is within 3.5% in the case of annual values. Computed monthly actual evapotranspiration is in excellent agreement with other studies. It is concluded that the model, with a calibrated set of seasonally varying parameter values, is a viable approach for the study of the moisture regimes of catchments.
Prediction of mound geometry under recharge basins
Authors: Singh Rameshwar
Published: February 2008

A rising water table under a recharge basin or under a sanitary landfill presents health and engineering problems. Design of recharge facilities close to urban centers requires determination of the transient location of the water table in the general vicinity of a recharge site. This involves solution of the Laplace equation subject to appropriate boundary and initial conditions. Phreatic surface conditions with and without accretion are nonlinear and extremely complex. Solutions have been obtained either by the linearization of phreatic surface conditions or by the use of other simplifying assumptions. Such solutions are usually inapplicable in regions of steep hydraulic gradients. A general technique for computing the transient location of the water table mound under finite width longitudinal and circular recharge basins is presented, which avoids the need for any limiting assumption or linearization. Computations were carried out on the Control Data Corporation (CDC) 3300. The results are presented graphically in terms of dimensionless parameters. Comparisons with other known solutions are made wherever it is appropriate.
A numerical study of confined‐unconfined aquifers including effects of delayed yield and leakage
Authors: Ehlig Christine , Halepaska John C.
Published: February 2008

This report presents a numerical model in radial coordinates for a well penetrating a homogeneous isotropic aquifer of constant thickness. The model defines variations in the transmissivity and effective storage coefficient as functions of the potential. This allows an approximation for the problem of a well pumping in an initially confined system which becomes unconfined near the well as the potential surface drops below the confining layer of the aquifer (confined‐unconfined problem). The model is used to investigate effects of delayed yield and leakage in confined‐unconfined aquifers. Drawdown versus time curves are presented for a variety of boundary conditions. Results show that the conditions producing an inflection in the drawdown versus time curves are not unique and illustrate the difficulty in attempting to determine aquifer characteristics from pumping test data.
The efficiency and equity of cost allocation methods for multipurpose water projects
Authors: Loughlin James C.
Published: February 2008

The efficiency and equity of the separable costs‐remaining benefits (SCRB), alternative justifiable expenditure, and use of facilities methods of cost allocation are examined. On efficiency grounds, only the SCRB formula satisfied all three efficiency criteria. From an equity viewpoint, no one method allocates costs so that each purpose shares fairly in the savings from multiple‐purpose development. The source of inequity with the SCRB and alternative justifiable expenditure methods arises because either separable costs or specific costs are subtracted from justifiable costs on a 1:1 basis. Conceptual problems in defining capacity preclude the use of facilities method from satisfying the equity objective. An adjustment in the SCRB method is proposed which will enable this procedure to satisfy both efficiency and equity criteria.
Morphometric definitions and classifications of Oxbow Lakes, Yukon River Basin, Alaska
Authors: Weihaupt John G.
Published: February 2008

Although oxbow lakes are seldom studied except as subsidiary topics in papers dealing with floodplains or river meanders, they are important because of the information that they can provide about (1) the processes affecting river meanders and meander cutoff, (2) the character and environments of the ancient rivers from which they formed, and (3) the nature and evolution of the oxbow lakes themselves. This paper suggests definitions, classifications, and morphometric techniques for studying oxbow lakes. The morphometric techniques are based upon oxbow lake shapes, dimensions, variable components, degree of complexity, degree of oxbow lake limb closure, and oxbow lake symmetry. These characteristics may be used as the basis for quantitative study.
Variation of width and discharge for natural high‐gradient stream channels
Authors: Osterkamp W. R. , Hedman E. R.
Published: February 2008

Standardized measurements of width at gaging stations on high‐gradient stream channels show that a power function relation, indicative of static allometric growth, exists between width and average discharge in the downstream direction. Results are in close agreement with studies by Leopold and Maddock (1953) and confirm their ‘b’ exponent. Workers currently using active channel width measurements as a means of estimating average discharge from ungaged basins should consider 2.0 as a standard exponent of the regression relation.
The effect of rainfall intensity on storm flow and peak discharge from forest land
Authors: Hewlett J. D. , Fortson J. C. , Cunningham G. B.
Published: February 2008

Analysis of an excellent 30‐year record of rainfall and storm flow (545 events) from a 3‐mi2 forested watershed in the southern Appalachians was made to determine whether rainfall intensity influences storm flow volume or peak discharge per unit area. For all practical purposes, hourly and minutely rainfall intensities during storms had no effect on storm flow volumes delivered by the basin. Storm rainfall P, antecedent flow I, season (winter or summer), and duration of the rainstorm D accounted for 86.4% of the total variation in the log of storm flow. Addition of maximum 60‐, 30‐, 15‐, and 5‐min intensities raised this to 86.7% (the increase was not significant at the 0.05 level) but reduced the standard error (0.354 in logs) by less than ½%. The same four variables (P, I,S, and D) accounted for 72% of the variation in the log of peak flow. Addition of the intensity variables raised this to 76.7% (increase significant at the 0.01 level). Thus only 4.7% of the total variation in the log of peak flow was attributable to intensity. Analysis by eight storm rainfall classes reinforced the conclusion that intensity added nothing to storm rainfall as a predictor of storm flow regardless of storm magnitude. P, I, S, and D accounted for 25–65% of the total variation in the log peak flows within storm classes; addition of all intensity variables raised this to 36–85%, but the increases were nonsignificant at the 0.05 level in four of the eight classes. A strong inference is made that neither estimates nor measurements of hourly and minutely rainfall intensity are of practical value in predicting storm flow volume from this forested basin. Furthermore, intensity played a much smaller role in peak discharge generation on this basin than was expected. The hypothesis is offered that rainfall intensity variation is not a dominant variable controlling flood generation in humid region, wild land watersheds.
Effects of spatial variability of soil hydraulic properties in water budget modeling
Authors: Peck A. J. , Luxmoore R. J. , Stolzy Janice L.
Published: February 2008

There is appreciable spatial variability of soil properties on the scale of a watershed or a field even in a single soil type. The spatial variation of soil water characteristics in an area was simulated from average properties and the assumption of scale heterogeneity (Philip, 1967). Simulated soil water characteristics and other data representing forest vegetation were used in a model to simulate water budgets over part of a watershed in eastern Tennessee for average April and July weather. Precipitation was assumed to be uniform over the area, and there was no runoff even from the least permeable soil during the months simulated. The spatial variability of soil water conditions had only a small effect on evapotranspiration. Water storage in the soil profile changed, so that the drainage flux beyond the root zone tended to become uniform throughout the area simulated. The characteristic microscopic length of the soil was assumed to be normally distributed in an area, and equations were developed for calculating average soil water characteristics from the retention curves and hydraulic conductivities of a number of soil samples. Components of the water budgets simulated with average soil water characteristics were in excellent agreement with the simulated behavior of the spatially variable soil unit as a whole. This result does not imply similar agreement for other distribution functions and soil‐plant‐weather combinations, but the methodology developed may be applied to investigate these problems.
The use of the Pearson type 3 and log Pearson type 3 distributions revisited
Authors: Bobee Bernard B. , Robitaille Roland
Published: February 2008

Different methods of fitting the Pearson type 3 and log Pearson type 3 distributions are applied to several long‐term records of annual flood flows previously tested for independence and homogeneity. By using this empirical comparison, it is shown that (1) the Pearson type 3 distribution conforms generally better to annual flood data than the log Pearson type 3 distribution, (2) it is preferable with respect to the log Pearson type 3 distribution to apply the method of moments to the observed sample rather than to the logarithmically transformed sample, and (3) it is important to correct the bias of the coefficient of skewness
Flow in fractured porous media
Authors: Duguid James O. , Lee P. C. Y.
Published: February 2008

The equations governing the flow of fluid through fractured porous media are derived. These equations consist of Darcy's law for fluid flow in the primary pores, equations of motion for fluid flow in the fractures, and two continuity equations. The system of equations is coupled by the interaction of fluid in the primary pores with fluid in the fractures. The coupling terms, which are incorporated in the continuity equations, describe the transient flux of fluid out of the primary pores and into the fractures. The finite element Galerkin method is used to solve this coupled system of equations for transient flow in a confined leaky aquifer. Solutions are obtained for both constant discharge and step drawdown problems. The importance of coupling the primary blocks to the fracture system and the effect of the acceleration term in the equation of motion in the fractures are studied by using this model.
Estimating the effective capillary pressure in the Green and Ampt Infiltration Equation
Authors: Brakensiek D. L.
Published: February 2008

A considerable amount of research indicates that the Green and Ampt infiltration equation can be used in hydrologic modeling with confidence. The parameters, however, still require considerable field and/or laboratory effort to determine estimated values. Reported here are alternatives for determining the average wetting front capillary pressure parameter. Only a moisture characteristic would be required.
An illustrative example of the use of multiattribute utility theory for water resource planning
Authors: Keeney Ralph L. , Wood Eric F.
Published: February 2008

Selecting a plan to develop the water resources of a region involves the consideration of economic, environmental, social, and technical objectives. Twelve attributes are defined to indicate the degree to which such objectives are achieved in the Tisza River basin of Hungary. A preliminary multiattribute utility function is assessed over these attributes. This is combined with existing information describing the possible consequences of five alternative development plans to yield an overall rating of their desirability. The utility function explicitly indicates the preference trade‐offs among attributes. Discussion indicates further uses of the utility function in the planning and evaluation processes.
Head gradient control in aquifers used for fluid storage
Authors: Molz Fred J. , Bell Lansford C.
Published: February 2008

Attempts to store fluids in confined aquifers will sometimes be frustrated by regional groundwater flow and/or by buoyancy drift due to density differences between the stored fluid and the native groundwater. Such effects can largely be overcome through the use of gradient control wells. A procedure based on linear programing can be used for the initial design of a well field that will create a zero gradient or a finite gradient in a given region. The finite difference form of the steady state groundwater equation provides one set of constraints, while the gradient condition in the storage region provides a second set. A standard linear programing solution routine is then used to provide the minimum pumping rates and head distribution consistent with the constraints and the chosen well array.
Rainfall network systems analysis: The optimal estimation of total areal storm depth
Authors: Lenton Roberto L. , Rodríguez‐Iturbe Ignacio
Published: February 2008

The design of rainfall networks for the purpose of estimating areal averages of rainfall is formulated as a mathematical programing problem whose objective function is the minimization of the cost and mean square error of the network and whose decision variables are the total number of rain gages, the coordinates of each of them, and the estimator weights. A two‐stage methodology is proposed, wherein the optimal configuration of the network is determined first, followed by the optimal estimator weights. A case study is presented in order to illustrate the various concepts developed in the paper.
Capital cost functions of a surface water treatment plant and its components
Authors: Hinomoto Hirohide
Published: February 2008

The capital cost function of a surface water treatment plant has been estimated in a few past studies, of which the best known are a study by Orlob and Lindorf and another by Koenig. The present study presents an estimate of the capital cost function of a surface water treatment plant and estimates of the plant's major components which have hitherto been unavailable in literature. The results of the past studies indicated economies of scale, but the results of the present study show small but positive diseconomies of scale in the capital cost of a plant with a capacity in a range of 1–12 mgd.
Governing equations for geothermal reservoirs
Authors: Brownell D. H. , Garg S. K. , Pritchett J. W.
Published: February 2008

Balance laws and constitutive relations are developed for convective hydrothermal (liquid water and liquid water–steam) geothermal reservoirs. A fully interactive rock‐fluid system is considered; typical rock‐fluid interactions involve momentum and energy transfer and the dependence of rock porosity (and permeability) upon the fluid and rock stresses. The geologic stress‐strain behavior treatment permits the nonlinear and history‐dependent constitutive behavior of the material to be properly taken into account.
Modeling daily precipitation occurrence process with Markov Chain
Authors: Chin Edwin H.
Published: February 2008

Daily precipitation records for 25 years at more than 100 stations in the conterminous United States have been analyzed. The order of the Markov chain representing the conditional dependence of precipitation occurrences at each station has been studied. This is done by using a decision procedure based on an extension of the principle of maximum likelihood. A loss function composed of a log‐likelihood ratio term and a degree‐of‐freedom term is used as the decision criterion. Among several competing Markov orders, the one that minimizes this loss function is selected. The results show that the order of conditional dependence of daily precipitation occurrences depends on the season and geographical location. There exists a prevalence of first‐order conditional dependence in summer and higher‐order conditional dependence in winter. An explanation based on meteorology is proposed. In both seasons, there are areas where the Markov order deviates from the prevalent patterns. If the record length is too short (n ≪ 1000 days), there is a tendency for a low‐order chain to be misrepresented as the proper model. A specific example in which a third‐order model is required to depict the precipitation occurrence in winter is also given in some detail. Therefore the proper Markov order describing the daily precipitation occurrence process has to be determined and cannot be assumed a priori. The common practice of assuming that the Markov order is always 1 is unjustified.
Estimates of low flows using watershed and climatic parameters
Authors: Chang Mingteh , Boyer Douglas G.
Published: February 2008

The lowest 7‐day streamflows (10‐yr return period, Q10) of 12 Monongahela tributaries in West Virginia were estimated from watershed and climatic parameters. Of the parameters studied, watershed perimeter alone accounted for about 88% of the spatial variability of 7‐day low flows in a multiple‐regression analysis. Main channel length and watershed form increased the predictability to about 95%. Precipitation and temperature parameters, which were highly correlated with watershed elevation and latitude, raised the R2 to 0.999. The standard error of estimate was 7.43 ft3/s, or about 30‐ of the observed mean; this result, an order of magnitude smaller than that obtained in an earlier study, suggests that meaningful low‐flow estimates can be obtained from watershed parameters alone in a mountainous humid region.
Sequential explicitly stochastic linear programing models: A proposed method for design and management of multipurpose reservoir systems
Authors: Huock Mark Hedrich , Cohon Jared L.
Published: February 2008

A sequential explicitly stochastic linear programing model (SESLP) which consists of a nonlinear program and an algorithm for obtaining an approximate solution is presented. The SESLP model can be used either to determine for a multipurpose multiple‐reservoir system both a design and a management policy or to determine only a management policy. A discrete lag‐one Markov process is explicitly included in the model as the streamflow description. The approximate solution to the nonlinear program is obtained by sequentially solving two linear programs which are subsets of the nonlinear program. A method of significantly reducing the computational burden and data requirements of the SESLP model is also presented. The method (system coordinated performance‐individual operation (Scorpio)) is effective because within the SESLP/Scorpio model, although the operating rules for each reservoir are dependent on events occurring only at that reservoir site, system‐wide performance levels are measured and the operation of each reservoir is coordinated with all other reservoirs.