bluuebunny/crossref_metadata_2025 huggingface dataset:
Migration of Pollutants in a Glacial Outwash Environment, 2
Authors: Crosby James W. , Johnstone Donald L. , Fenton Robert L.
Published: February 2008

A test drilling program was conducted at a local dairy in the Spokane Valley, Washington, to determine the effects of feedlot operation on groundwater quality. Coliform bacteria, enterococci, and fecal coliforms were found to die off within a relatively few feet of the ground surface. Chlorides and nitrates, however, proved to be persistent in depth and may actually reach the groundwater body. The low natural moisture content of the soil, coupled with the apparent high moisture tensions, suggests that soil moisture is not presently moving downward in the system. It is concluded that the downward migration of inorganic chemicals from the feedlot environment must represent an early phase of the operation, which is arrested as organic mattes are formed in near‐surface layers.
General Multistage Marginal Cost Dynamic Programing Model for the Optimization of a Class of Investment‐Pricing Decisions
Authors: Riordan Courtney
Published: February 2008

A general method is developed for finding an optimal solution to the dynamic investment‐pricing problem of a publicly owned or regulated monopolistic enterprise with a technology of production exhibiting economies of scale given a market demand for the output of the enterprise that is sensitive to price. Previous authors have dealt successfully with the same capital investment problem under the assumption of completely inelastic demand; price has thereby been eliminated as a rationing device. The major significance of the general model developed here is that it combines the theory of welfare economics and the dynamic programing technique to solve the joint investment‐pricing problem under a particular, but not too restrictive, set of structural and procedural assumptions.
Application of User Charges to Water Quality Management
Authors: Upton Charles
Published: February 2008

The problems of user charges as a device for regulating the discharge of pollutants are considered for the Miami (Ohio) river basin. Cost functions for treatment processes are estimated for this basin. The analysis indicates that if taxes are levied to achieve the minimum cost of meeting a water quality standard, the receipts would pay about 85% of the cost of centralized treatment. However, user charges levied to pay for centralized treatment would erase this deficit at an additional total cost of only about 1%.
An Algorithm for Needle Ice Growth
Authors: Outcalt Sam I.
Published: February 2008

The morphology of needle ice growth is variable owing to entrapment of mineral soil particles, freezing plane depth, and banding. This paper attempts to link these morphologic variations to the needle growth environment by means of a simple algorithm. The algorithm is based on the hypothesis that morphologic variability can be traced to variability in surface energy transfer, soil water tension, and the thermal‐hydraulic properties of the near‐surface soil layers during needle evolution.
Computer Determination of the Geometry and Topology of Stream Networks
Authors: Coffman D. M. , Turner A. K.
Published: February 2008

Previously proposed binary string procedures for describing stream network topology do not greatly assist geomorphic and engineering studies that require network geometry information. A variation of these procedures is described that can determine the network geometry as well as its topology. Two years' experience has shown that this extension of the, binary string methods, which includes geometric properties, is an efficient and practical method of studying real stream networks.
Note on the Map Scale Effect in the Study of Stream Morphology
Authors: Yang Chih Ted , Stall John B.
Published: February 2008

The Strahler stream order assigned to a particular stream segment depends on the scale of the topographic map used in ordering the stream network. However, the Horton‐Strahler bifurcation ratio of stream number, stream length ratio, and stream concavity are found to be independent of map scale. The coefficients in Horton's laws obtained from a map system of one scale can be transferred to a map system of another scale if the stream order difference between the two map systems is given. Yang's theoretical and equilibrium longitudinal stream bed profiles are shown to be independent of map scale and can be compared favorably with an actual profile obtained from a topographic map of any scale.
Pollution Charges Income and the Costs of Water Quality Management
Authors: Boyd J. Hayden
Published: February 2008

A river basin authority seeking to maximize the economic value of a river's pollutant disposal and water quality services may limit pollutant discharges and/or increase the river's waste assimilative capacity. Pricing pollutant disposal induces disposers to recognize the opportunity cost of this service, or the value of downstream water quality foregone at the margin. The income from pollution charges can also reimburse the authority for the cost of capacity augmentation. There is some evidence that optimal pollutant charges would yield less than the cost of an optimal level of artificial aeration because of mild scale economics. Low flow augmentation, similarly optimized, should earn a surplus because of both diminishing marginal product and eventual increasing cost of reservoir storage.
Optimal Intraseasonal Irrigation Water Allocation
Authors: Dudley Norman J. , Howell David T. , Musgrave Warren F.
Published: February 2008

Determining the optimal timing of irrigations over a season in an uncertain environment is a significant problem in operating and planning irrigation schemes. In the absence of suitable experimental results, a plant growth‐soil moisture simulation model is incorporated into a two state variable stochastic dynamic programing model to determine the optimal intraseasonal allocation pattern for irrigation water in a variable environment. Historical traces of climatic data are used, although these data could be synthesized. Given the initial assumptions within the model, the results suggest that an irrigator should maintain available soil moisture in the root zone at a high level, even if it means exhausting the water supply early in the season. However, optimal irrigation strategies are sensitive to changes in the biologic assumptions within the model and thus indicate the importance of good experimental data on which to base these assumptions.
A Model of the Hydrology of the Lakes of the Lower Grand Coulee, Washington
Authors: Friedman Irving , Redfield Alfred C.
Published: February 2008

The lakes that occupy the abandoned gorge of the Columbia River below Dry Falls, Washington, were formerly fed by groundwater and precipitation, and they lost water solely by evaporation. As a result the lower lakes became saline. Since 1951 an inflow of irrigation water from the development of the Columbia Basin Irrigation Project has caused the lakes to freshen. The lake levels are now controlled by pumping excess water directly from Lake Lenore and from protective wells drilled around the perimeter of Soap Lake. Data on the distribution of deuterium and chloride in the system, on measurements of the flow of water between two of the lakes, and on measurements of the pumpage have been used to develop models of the system for preirrigation and postirrigation periods. The models indicate the quantities of water that entered each lake from natural sources and from the irrigation system and that left by evaporation and by flow or seepage between the lakes, e.g., the quantities required to maintain the balance of water and chloride in the several lakes and in the system as a whole and to reproduce the distribution of deuterium and chloride in the lake waters. Annually prior to irrigation about 14 × 106 m3 of water entered the system and escaped by evaporation. About 20% of this amount was precipitated on the lake surfaces. The remainder was groundwater that entered in about equal quantities two areas separated by, the Park and Blue lakes; the groundwater seepage into these two lakes appears to have been negligible. Precipitation and groundwater have introduced 93 tons of chloride annually, and chloride has accumulated in Soap Lake at the same rate. At this rate 2350 years would have been required for the accumulation of the preirrigation chloride in Soap Lake. At present 20 × 106 m3 of irrigation water enters the system annually. The accessions of irrigation water, like those of natural groundwater, are limited to two areas separated by the Park, Blue, and Alkali lakes. The protective wells intercept much of the irrigation water and natural groundwater that would otherwise enter Soap Lake. The flow of water through the lakes is 1.7 of that prior to irrigation. The wells remove from the lakes 2550 tons of chloride annually, which is 25 times the annual inflow; this removal is rapidly reducing the chlorinity of Lake Lenore and Soap Lake. The history of the lake system in relation to changing climate is discussed.
Hydrogeology of Ash Flow Tuff: A Preliminary Statement
Authors: Winograd Isaac J.
Published: February 2008

Ash flow tuffs, silicic pyroclastic rocks commonly mapped as silicic lava flows (rhyolite, dacite, or quartz latite) on many pre‐1960 geologic maps, cover tens of thousands of square miles in the southwestern states and aggregate between 35,000 and 60,000 mi3 in the Great basin alone. In contrast to silicic lava flows but similar to basalts, ash flow tuffs are sheetlike bodies; individual flows have been traced for as much as 100 miles. Welding, the cohesion of molten glassy shards and pumice fragments during emplacement of these rocks, results in significant vertical variations in physical properties within individual flows. Interstitial porosity and permeability vary from 70% and 2 gpd/ft2 (gallons per day per square foot), respectively, in nonwelded portions or zones of ash flows to less than 5% porosity and virtually zero permeability in densely welded zones. Primary and secondary joints spaced several feet apart in nonwelded zones are as close as a fraction of an inch in densely welded zones. Fracture transmissibility of welded zones within ash flow tuffs varies from 100–100,000 gpd/ft. The nonwelded zones are aquitards. Spring groups with discharges ranging from 20–200 cfs (cubic feet per second) emerge from welded tuff in eastern Idaho and Sumatra, Indonesia. The magnitude of the spring discharge attests to the regional hydraulic continuity of these strata. Development of groundwater from welded tuff in the Southwest appears several decades away because of depth of burial, large variations in yield, and locally poor water quality. Nevertheless, further study of these rocks is warranted to test the assumption common to many water budget studies that interbasin movement through and ‘mountain front recharge’ from silicic volcanic rocks are negligible.
Some Long Run Effects of Water‐Pricing Policies
Authors: Gysi Marshall , Loucks Daniel P.
Published: February 2008

The long run effects of various pricing policies are investigated in terms of consumer benefits and system costs. Price can play a major role in planning by delaying expansions and lowering system costs. A combination of summer differential plus increasing block rate structure appears to offer the greatest net benefits to the system.
Formation of Riffles and Pools
Authors: Yang Chih Ted
Published: February 2008

The formation of riffles and pools in natural streams is a means of self‐adjustment that minimizes their time rate of potential energy expenditure per unit mass of water in accordance with the law of least time rate of energy expenditure. The actual formation of pools and riffles is a combined process of dispersion and sorting.
Algebraic technological function from a simulation model
Authors: Maddock Thomas
Published: February 2008

Distributed parameter groundwater simulation models are difficult to couple explicitly with management models that seek to optimize an economic objective. For a groundwater system whose drawdown in response to pumping was modeled by a two‐dimensional linear partial differential equation, an algebraic technological function was produced that related seasonal pumping at wells in the system to drawdown at those wells. The algebraic technological function allowed an explicit coupling of the groundwater model with a quadratic programing management model.
A regional groundwater resource management model
Authors: Maddaus William O. , Aaronson Michael A.
Published: February 2008

This paper demonstrates the application of a groundwater quantity and quality model to large‐scale groundwater basin management. The model employs a finite difference formulation of groundwater flow to compute the groundwater elevations at the node points of a two‐dimensional homogeneous aquifer. A compatible groundwater quality model uses a control volume or mass balance approach to compute the concentration of a conservative constituent at each node. The model was calibrated to a 1200 mi2 groundwater basin in central California. Over 300 nodes were used in a symmetrical network. Water and waste water management alternatives are input to the model: amounts of pumping, natural infiltration, surface water use, and waste water recharge at selected future dates are specified. The impact of five alternatives on the groundwater basin over a simulated 45 years of operation is shown. Thus the evaluation of alternative water resource management schemes was based, in part, on model performance. This type of groundwater model shows promise as an integral tool in planning and managing the development of groundwater basins.
Mathematical programing for regional water quality management
Authors: Graves Glenn W. , Hatfield Gordon B. , Whinston Andrew B.
Published: February 2008

This paper details an application of mathematical programing to the problem of optimal water quality control in an estuary. The mathematical models allow for the possibilities of at‐source treatment, regional treatment plants, and by‐pass piping. Actual data from the Delaware Estuary are used to solve a large‐scale problem and the solution is given. The results indicate that a regional treatment system for the Delaware Estuary is superior, in terms of total cost, to other proposed schemes.
Chance constrained reservoir model
Authors: Eisel L. M.
Published: February 2008

A chance constrained model of an irrigation reservoir is developed that employs a more general reservoir operating policy than previous chance constrained reservoir models. Development of this model demonstrates the possible convolution problems associated with chance constrained models of water resource systems. The optimal reservoir design and operating parameters resulting from model solution are investigated in a simple reservoir simulation model employing operational hydrology. Results of the simulation studies validate the chance constrained reservoir model.
Errors in output of hydrologic models due to errors in input potential evapotranspiration
Authors: Parmele Leslie H.
Published: February 2008

A study was conducted to give some perspective to the importance of accurate evapotranspiration (ET) input data to hydrologic models. For the analysis, computed output from three hydrologic models was considered as the true watershed response. Variations in the form of random fluctuations and fixed biases were introduced into the potential evapotranspiration (Pet) input data of the test models. By leaving the other inputs and parameters unchanged, such an analysis shows the effect of evapotranspiration on streamflow under the regulation of the other components in the model. It is shown that a constant bias of 20% in the Pet input data has a cumulative effect and results in considerable error in the computed hydrograph peaks and recession characteristics, whereas the influence of the random error on estimated streamflow was generally not measurable for the watersheds and models studied.
Radiant energy transfer in waters
Authors: Viskanta R. , Toor J. S.
Published: February 2008

A model is presented for predicting the local radiant flux and the net rate of gain or loss of radiant energy per unit volume on spectral and total bases for a layer of natural water by using exact radiative transfer theory. The model considers attenuation (absorption and scattering) and multiple scattering by water and accounts not only for the transmission and internal reflection of radiation at the air‐water interface but also for reflection at the bottom. Some numerical results are reported for pure water, multiple scattering being neglected. The results show that analyses that neglect the spectral nature of the incident flux and assume water to be gray lead to appreciable errors in total radiant flux computations and in the amount of internal absorption of solar radiation. For accurate predictions, the reflection from the bottom and the internal reflection from the air‐water interface must be properly accounted for in shallow waters.
Source areas and climatic effects in carbonate groundwaters determined by saturation indices and carbon dioxide pressures
Authors: Shuster Evan T. , White William B.
Published: February 2008

A previous study of 14 carbonate springs in Nittany valley in central Pennsylvania showed that the feeder system for the springs could be characterized as conduit flow or diffuse flow on the basis of the variability in water chemistry. Saturation indices and CO2 partial pressures calculated from the raw data of the previous study were then sorted into monthly groups and averaged. Conduit springwaters are always aggressive with respect to both calcite and dolomite, no seasonal trend being in evidence. The high variability reflects mostly variation in recharge, short residence time, and slow kinetics of equilibration between water and wall rock. Diffuse springwaters are somewhat aggressive with respect to calcite during the growing season but become somewhat supersaturated during the winter. Waters from diffuse‐flow springs in dolomite are nearly at saturation, whereas waters from diffuse‐flow springs in limestone are always undersaturated with respect to dolomite. The equilibrium CO2 pressures of conduit springwaters show a regular seasonal trend having a pronounced maximum during the growing season. The CO2 content of diffuse‐flow springs is highly variable, and although the summer maximum is present, the CO2 content also reflects variations in the CO2 production in the catchment areas of infiltrating waters.
Solutions of hydrodynamic dispersion in porous media
Authors: Eldor Menahem , Dagan Gedeon
Published: February 2008

Problems of hydrodynamic dispersion in porous media with radioactive decay and/or adsorption of the tracer are solved by an approximate analytical method. The flow of the carrier fluid is assumed to be steady and two dimensional. Initially a sharp front separates two regions of different constant tracer concentrations. The general solution is applied to a few examples of hydrologic interest: radial flow from a recharging well, a recharging well in a uniform flow field, two wells, and soil leaching by uniform recharge.
Seasonal sediment yield patterns of U.S. rivers
Authors: Wilson Lee
Published: February 2008

The sedihydrogram is a double log plot of mean monthly sediment yield against mean monthly water yield. A line connecting consecutive months indicates the seasonal rhythm of erosion and runoff occurring in a drainage basin. Sediment regimes seen on the sedihydrogram are explained by a model that relates basin hydrology to the dominance of common air masses. Mediterranean and continental climate and erosion regimes are well expressed in U.S. rivers. Mediterranean regimes in the western United States have a dry summer and a wet winter with strong seasonal contrasts between early wet season floods and less turbid flow events later in the wet season. Large sediment yield values may be expected from basins in which seasonal desiccation alternates with heavy rains. Continental regimes in the central and eastern United States have a water yield event in late winter or early spring with a low sediment concentration. Summer storms produce high concentrations and a low water yield. The summer component of the sedihydrogram is dominant in dry regions but minor in humid areas, where vegetation offers effective protection from storms. Land use factors influence sedihydrogram patterns. Basins in eastern humid states have a sedihydrogram typical of arid regions if strip mining or urbanization has had an important effect on the basin hydrology. Most climate regimes show a seasonal shift in the parameters of the sediment transport curve, so that an analysis of seasonally grouped data results in improved equations for relating sediment movement to environmental controls. The prediction of sediment yield requires that separate consideration be given to those factors affecting runoff and those affecting sediment concentration.
Hurst phenomenon in turbulence
Authors: Nordin Carl F. , McQuivey Raul S. , Mejia Jose M.
Published: February 2008

Records of turbulent velocity fluctuations from both laboratory flumes and rivers exhibit the Hurst phenomenon, R/S ∽ sH, where R is the range of the cumulative sum of departures from the mean for a time series of length s, S is the standard deviation of the time series, and 0.5 ≤ H ≤ 1. The Hurst phenomenon suggests long‐term persistence in a time series. The implications in turbulent flows are that the integral time scales do not exist and, rather, that the turbulent velocity fluctuations have the properties of fractional Gaussian noise. Some indirect evidence from dispersion studies supports these implications.
Cost sharing and multiobjectives in water resource development
Authors: Marshall Harold Emory
Published: February 2008

The U.S. Water Resources Council has considered objectives in addition to national economic development for the evaluation of water projects. Cost‐sharing rules have not been proposed for the new objectives. A conceptual method is proposed for planning the nationally optimal project with multiobjectives. The data required for project evaluation with multiobjectives are used to apply a cost‐sharing rule that induces local interests to choose nationally efficient projects. The rule is recommended for traditional project purposes and some new purposes. It can be applied to a multiple‐purpose project without allocating project joint costs. A ceiling and a floor on local percentage cost shares of 100% and 20% of project costs, respectively, are considered for traditional purposes. Local percentage cost shares of 50% and 100% are considered for all costs allocated to environmental quality and regional development objectives, respectively.
Development and display of multiple‐objective project impacts
Authors: Miller W. L. , Byers D. M.
Published: February 2008

This research develops and illustrates composite trade‐off functions that can be used to display the relationship between the economic efficiency and environmental quality impacts of investment in a water resource project. The composite trade‐off model is applied to analysis of some aspects of environmental quality and economic efficiency in a Soil Conservation Service small watershed project. This application demonstrates the feasibility of using this technique and describes some environmental enhancement occurring through land treatment programs.
Flow near a pumped well in an unconfined aquifer under nonsteady conditions
Authors: Streltsova T. D.
Published: February 2008

The problem of unsteady radial flow in an unconfined aquifer is considered as a boundary value problem with discontinuous initial conditions at the surface of the well. The discontinuity of heads occurs at the surface of the well as pumping commences; it dies down in time exponentially and thus represents the delay of the transitional process of reestablishing equilibrium in time. The downward variable movement of water in the vicinity of the well resulting from this discontinuity is proportional to the difference between the gradually falling water table and the average head and is a cause of the slow draining of the unconfined aquifer. The contribution of the unsaturated zone of the aquifer in the process of slow drainage is usually of minor importance and subordinate as far as most drainage problems are concerned. Experimental verification and model design are presented.
A technique using porous cups for water sampling at any depth in the unsaturated zone
Authors: Wood Warren W.
Published: February 2008

Porous cups or suction lysimeters provide a simple and direct method for collecting water samples in the unsaturated zone. A new procedure is described in which a check valve is placed in the sample collection assembly. This construction permits complete collection at any depth without the loss of samples. A detailed description of construction and operation illustrates the advancement over previous designs.
Nitrogen and phosphorus losses in surface runoff from agricultural land as influenced by placement of broadcast fertilizer
Authors: Timmons D. R. , Burwell R. E. , Holt R. F.
Published: February 2008

Nitrogen (N) and phosphorus (P) losses were determined in the sediment and water components of surface runoff from fertilized and unfertilized plots on a Barnes loam soil located in west‐central Minnesota. Simulated rainfall was used to cause surface runoff from small fallow plots that received uniform amounts of N and P but that had a different placement of the broadcast fertilizer. Deep incorporation of the fertilizer by plowing down (and subsequent disking) caused N and P losses about equal to those in surface runoff from unfertilized plots. The highest nutrient losses occurred when the fertilizer was broadcast on a disked surface.
Simulation of hydrochemical patterns in regional groundwater flow
Authors: Schwartz Franklin W. , Domenico Patrick A.
Published: February 2008

The chemical state of a regional groundwater system in which several different processes are acting is described by a partial equilibrium simulation model that incorporates mass transfer rates and reaction kinetics. Quantitative analysis with the model indicates that mineral dissolution, saturation constraints on dissolution, the degree of saturation, partial pressures of CO2 gas, and reaction kinetics in relation to the residence time of the groundwater flow play different roles in determining the spatial distribution of ionic constituents. Simultaneous evaluation of several geochemical processes permits the study of interdependent phenomena such as shifts in equilibrium concentrations resulting from the addition of common ions by cation exchange or sulfate reduction processes. The utility of the model is demonstrated by applying it to the groundwater reservoir in the Upper Kettle Creek, Ontario, Canada, where a favorable comparison is achieved between the real and the theoretical hydrochemical patterns.
Forecasting water use for electric power generation
Authors: Young H. Peyton , Thompson Russell G.
Published: February 2008

Knowledge of demand functions for water and electricity provides a basis for forecasting water withdrawals, water consumption, and heat discharges to the water in electric power generation. The variables in these demand functions may be significantly affected by direct and indirect variations in policy. Forecasts of water withdrawals and consumption of water are made for alternative combinations of the variables in the demand functions and compared with the results of previous studies in which the demands for water were forecast as ‘requirements.’
Monitoring snow water equivalent by using natural soil radioactivity
Authors: Bissell Vernon C. , Peck Eugene L.
Published: February 2008

The attenuation by snow cover of natural gamma radiation emitted from the soil serves as an excellent index to the water equivalent of the snow cover. A small portable gamma ray detector was installed on a boom about 2 meters above the ground at the National Oceanic and Atmospheric Administration‐Agricultural Research Service (ARS) cooperative snow study site at the ARS Sleepers River watershed near Danville, Vermont, for the 1970–1971 snow season. Comparison of gamma ray count rates with snow measurements taken at the site indicates that the small unshielded gage could be used to measure snow water equivalent (range 5–40 cm) with a standard error of 1.5 cm without preliminary editing of gamma ray count rates. A major source of this error was the deposition of radioactive aerosols on the snow surface by precipitation. The deviation of gamma ray count rates due to precipitation events is short‐lived, and a simple editing procedure on the count rate time trace reduced the snow season standard error to 1.1 cm. The edited count rate yielded 6% error in the 5‐ to 13‐cm water equivalent range, decreasing to 4% in the 25‐ to 40‐cm water equivalent range. This measurement method could be extremely valuable in providing unmanned measurement of snow water equivalents at remote locations.
Clogging in simulated glacial aquifers due to artificial recharge
Authors: Ripley David P. , Saleem Z. A.
Published: February 2008

Clogging due to artificial recharge in laboratory‐simulated unconsolidated aquifers displayed two types of patterns. The first type, resulting from recharge with turbid water containing an effective microbial inhibitor, showed clogging throughout the aquifers ranging in length from 48 to 123 cm. The rate of clogging at different depths was dependent on the size distribution of the particles in the water relative to the pore size distribution of the porous media. Clogging tended to be more severe at the influent portion of the sample; however, when the particles in the recharge water were smaller in size or when the pore sizes of the porous media were larger, the result was a more uniform rate of clogging with respect to depth. The second type, resulting from recharge with nonturbid water and no effective microbial inhibitor, shows clogging only in the top few centimeters. If it is not understood that these two patterns result from different causes, such a pattern resulting from the combined factors could be attributed to only one cause, namely, turbidity. Such a decision could lead to the conclusion that clogging due to turbidity will not penetrate deeply into the porous media, whereas if little microbial clogging is occurring, the result will be more clogging at greater depths.
Sample error of T‐year events commuted by fitting a Pearson type 3 distribution
Authors: Bobée Bernard
Published: February 2008

Estimation of events with given return periods and the sampling variance of these events are of great importance in hydrology. In the case of Pearson type 3 and gamma distributions that efficiently describe the hydrologic extreme values, floods, for example, the usual formulas are based on simplified assumptions such as neglecting the variability of the skewness coefficient. More general relationships are derived and then compared with the simplified ones. Great differences may happen: for instance, for large return periods the confidence interval is underestimated, specially when C8 ≠ 2CV, whereas for return periods T < 20 the confidence interval given by usual methods is overestimated. These errors in estimating the confidence intervals may come out with economical implications, particularly in works constitution. This result shows the importance of using the most representative formulas.
Forest transpiration greatly speeds streamflow recession
Authors: Federer C. A.
Published: February 2008

Streamflow recessions from a 42‐ha forested watershed in New Hampshire are greatly affected by transpiration. In the dormant season, recession flow continues for many days at rates around 1 mm/day, whereas, in the growing season, Streamflow rate declines in several days to less than 0.05 mm/day. Transitions between the two regimes occur in June and late September or early October, corresponding to the leaf out and color change phenology of the area. Elimination of transpiration by cutting and herbiciding a 16‐ha watershed changed the rate of its summer recession from the rapid decline associated with transpiration to the slow recession characteristic of no transpiration. The recession without transpiration is probably maintained by slow drainage of unsaturated soil, since groundwater exists only during snowmelt on these steep watersheds. Rapid recession occurs when transpiration over the whole watershed removes soil water that would otherwise drain and become Streamflow.
The Operation of a Stream‐Aquifer System Under Stochastic Demands
Authors: Maddock Thomas
Published: February 2008

It is possible to develop operating rules for the conjunctive use of surface water and groundwater when the demand and supply sources are stochastic. These rules allow the quantities of water pumped from wells, diverted from streams, spread, and returned to the stream after use to be determined for a given time period even if the required needs and availability of supply are uncertain at the beginning of the time period. These rules are dependent on a technological function relating streamflow interaction with well pumping and with the statistics of the demands, streamflow, pumping, and drawdowns.
Optimal Planning for a Thermal Discharge Treatment System
Authors: Dracup John A. , Fogarty Thomas J.
Published: February 2008

The characteristics and economic implications of thermal pollution are considered within the context of the planning of a treatment system for a series of hypothetical nuclear power plants that are to be located adjacent to a river. It is assumed that these power plants will discharge sufficient heated cooling water to make these treatment facilities necessary. The problem that is being considered is to determine the optimal planning of a treatment system. The objective of the planning procedure is to minimize the total annual cost for the construction and operation of the entire system. The constraint on this minimization process is not to violate a maximum temperature requirement within each reach or section of the river. The problem is solved by considering the effect that a bypass‐piping system has on temperatures within the river. The technique of bypass piping consists of piping waste water downstream to reaches of a river where the regenerative powers of the physical system have reduced the level of pollution to the extent that more waste water may be disposed. By noting that the bypass‐piping system allows the beginning and end temperatures of a section of the river to be controlled, a procedure can be developed for separating the optimization model of the entire system. This model is separated into a set of small subproblems that are solved by simulation and a system problem that is solved by dynamic programing. The results of the implementation of this model showed that the bypass‐piping system significantly reduced the cost of the entire treatment system.
The Locomotor Response of Goldfish to a Steep Gradient of Copper Ions
Authors: Westlake G. F. , Kleerekoper H. , Matis J.
Published: February 2008

The intent of this investigation was to verify whether the previously observed attraction of the goldfish to a sublethal concentration of copper ions presented in a shallow gradient also occurs when the fish are confronted with a steep gradient of the same concentration. The locomotion of goldfish exposed to laboratory water and a steep gradient of ‘copper‐polluted’ water in a free choice situation was monitored to establish the orientation of the fish in relation to the copper‐containing mass of water. Separate tests were made for 0.005, 0.01, 0.025, and 10.0 ppm Cu++ at 21°C ± 1° in continuously flowing water. In all concentrations the number of entries into the copper‐affected zone and the time spent there per entry decreased significantly. Absolute avoidance of the copper‐containing water mass did not occur even at 10.0 ppm. It is apparent that the locomotor response of the fish is dependent on the slope of the gradient of the copper ion, all other conditions being similar. A steep gradient may elicit avoidance escape; a shallow gradient may produce ‘attraction.’
Effects of Colorado River water quality and supply on irrigated agriculture
Authors: Moore C. V. , Snyder J. H. , Sun Peter
Published: February 2008

A production function relating irrigated crop yield to the quality and supply of irrigation water is developed. It was found that the adverse effects of saline irrigation water can be offset by application of additional water over and above that required for plant transpiration. Results indicate that a degradation of the water supply in the Colorado River at Imperial Dam from the existing level of electroconductivity of 1.50 mmho to the projected level for the year 2000 of 2.0 mmho would cause a decline in the return to land and water of about 14% for farmers in the Imperial Valley of California. Because of the relatively elastic demand for irrigation water at the current price, any attempt to ration water through a market price mechanism would have no effect, unless water rates were about double their current levels.
Quality of water discharged from two agricultural watersheds in southwestern Iowa
Authors: Burwell R. E. , Schuman G. E. , Piest R. F. , Spomer R. G. , McCalla T. M.
Published: February 2008

The quality of water discharged from a 157.5‐ha diversified conservation‐farmed watershed in southwestern Iowa was within acceptable limits for potable water except for the levels of ammonia, inorganic phosphorus, and coliform. Total coliform levels exceeded the established criteria on two occasions, and fecal coliform once during the 2‐year study. Nutrient concentration was high occasionally, but the nutrient quantities discharged from the watershed were low, the effectiveness of the level‐terrace system in controlling surface runoff and erosion thus being shown. Atrazine residue in the runoff and sediment was detected in only one sample. Even though several chlorinated hydrocarbon and organophosphate compounds had been applied to the watershed, none was detected in runoff or sediment. A comparison of the data from a 33.6‐ha contour‐farmed watershed with the data from the 157.5‐ha well‐planned conservation watershed showed the benefits and necessity of using some means of controlling runoff and erosion to prevent loss of agricultural chemicals that may degrade our surface waters.
Toward the structure of a production function for wheat yields with dated inputs of irrigation water
Authors: Minhas B. S. , Parikh K. S. , Srinivasan T. N.
Published: February 2008

The interdependence between the rate of water used by plants and the available stocks of moisture in the soil, the temporal interdependence between water use at different time points, and the consequences of these interdependencies for the relationship between time profiles as well as the quantities of water used by crop plants and yields have not generally been analyzed in a unified framework. We present one such unified framework for the analysis of optimal use of irrigation water. We have estimated from experimental data the mathematical form of a water use function and have used this function to compute the time profiles of actual water use for two crops: wheat in Delhi and alfalfa in Ohio. The estimated time profiles of consumptive use have been used to determine the relationship between wheat yields and dated inputs of water in Delhi.
Identification of parameters in an inhomogeneous aquifer by use of the maximum principle of optimal control and quasi‐linearization
Authors: Lin Albert C. , Yeh William W‐G.
Published: February 2008

Optimal identification of aquifer parameters in a distributed system is formulated as an optimal control problem. The dynamics of the head is governed by a second‐order nonlinear partial differential equation. The numerical example presented considers that the parameters to be identified are functions of the space variable. Observations on head variations are available at several observation wells distributed within the system. Spatial discretization is first used to transform the distributed system to a lumped system. The least squares criterion function is then established. After introducing the Lagrange multipliers, the maximum principle is applied to obtain the set of necessary conditions that is optimal. These conditions are expressed in terms of a set of canonic equations of two‐point boundary value type that is easily solved by the technique of quasi‐linearization. Thus aquifer parameters are directly identified on the basis of observational data taken at observation stations. The maximum principle formulation is inherently more accurate and stable, since it minimizes the least squares error over the whole time and space domains. Computationally, it is extremely efficient. The numerical example presented demonstrates simultaneous identification of 11 parameters defined at discretized points along the space variable. Quadratic convergence is also demonstrated by numerical experimentation.
Procedures for determining the order of dependence in streamflow records
Authors: Denny J. L. , Kisiel C. C. , Yakowitz S. J.
Published: February 2008

As will be documented in detail, a common feature of all the streamflow models in the literature is that they assume some known order of Markov dependency to be available prior to calibration of the model parameters. Yet the statistical methods for finding this order are subtle and perhaps may themselves need refinement. In brief, the problem of finding the minimum order of Markov dependence is a difficult one and yet one that must be faced no matter what streamflow model is selected. This study is devoted in the main to setting forth the extant statistical techniques available for this problem of determining Markov order and applying the stated techniques to finding the order of records of particular rivers in the Tucson basin. Care is taken in describing the hydrologic properties of the rivers studied, since these properties may ultimately be crucial in establishing some a priori feelings for the range of likely orders.
Worth of additional data to a digital computer model of a groundwater basin
Authors: Gates Joseph S. , Kisiel Chester C.
Published: February 2008

The worth of additional data to a digital model of the Tucson basin, Arizona, was computed by using a basic form of statistical decision theory. The model variables for which additional data were hypothesized included the aquifer coefficients of storage and transmissivity, initial water levels, discharge, and recharge. The worth of data was evaluated in terms of the expected reduction in error in predicted water levels associated with collection of more data on one variable at one point in the model. A limited number of tests suggested that the Tucson basin model could be improved most by obtaining more data on discharge and recharge in areas where these variables were large and by obtaining more data on transmissivity where it was uncertain. More data on initial water levels and storage coefficient commonly were less helpful. The sensitivity of the results to the assumptions made in postulating discrete frequency distributions with largely subjectively determined parameters for the model variables was estimated. These tests indicated that the numerical values for worth of data were sensitive to the assumptions but that the relative rankings of variables in terms of worth of added data remained constant.
On seawater encroachment in coastal aquifers
Authors: Lee Chun‐Hian , Cheng Ralph Ta‐Shun
Published: February 2008

The seawater encroachment in a coastal aquifer is studied by means of a mathematical model. In some aquifers the dispersion amalgamates the encroaching seawater and the discharging freshwater to produce an extensive zone of diffusion. The coupled nonlinear conservation equations of mass and of salt are formulated and solved by the finite element method with the aids of iteration and underrelaxation. The numerical procedure is verified by comparing solutions with known results in the literature. In this study the seawater encroachment in the Biscayne aquifer at Cutler area, Florida, is modeled; the numerical results are in good qualitative agreement with the field data obtained by Kohout.
Acid precipitation in the northeastern United States
Authors: Cogbill Charles V. , Likens Gene E.
Published: February 2008

Analysis of recent precipitation samples from the northeastern United States has shown a consistent pH of less than 4.4, when the expected pH based upon equilibrium with CO2 would be 5.6. A stoichiometric formation process being assumed, some 65% of the acidity is due to H2SO4, 30% to HNO3, and less than 5% to HCl. The pH values may be predicted from chemical content and generally agree to within 0.1 pH unit with the observed pH. The distribution of acid precipitation encompasses most of the northeastern United States. This pattern apparently has existed since about 1950–1955, but the intensity of acid deposition, especially that due to HNO3, has increased since then. Analysis of prevailing winds indicates that much of the acidity originates as a general source over industrial areas in the Midwest.
Hydrologic simulation of watersheds with artificial drainage
Authors: Campbell Kenneth L. , Johnson Howard P.
Published: February 2008

A deterministic hydrologic watershed model that simulates the watershed discharge and soil moisture status continuously throughout the crop season was developed for drainage watersheds with depressional storage. The model simulates the processes of interception, surface storage, infiltration, surface runoff, soil profile storage, percolation to the water table, subsurface tile drainage, soil moisture redistribution, evapotranspiration, and routing through depressions, tile mains, and the drainage ditch. The resulting outputs are daily evapotranspiration, soil moisture status in the crop root zone, and watershed discharge. The model simulated the watershed discharge and soil moisture status of the 24‐mi2 East Fork Hardin Creek watershed near Jefferson, Iowa, for the 1964 crop season as well as could be expected with the input data that were available. Discrepancies between the measured discharge and the predicted discharge were in part due to spatial variations in precipitation over the watershed, which were not accounted for in the model input data.
Estimating land use characteristics for hydrologic models
Authors: Gluck William R. , McCuen Richard H.
Published: February 2008

Many hydrologic models, including both linked process simulation models and unit hydrograph models, require estimates of land use characteristics (e.g., percentage of impervious area) for calibration. Past investigations have demonstrated that reliable estimates of land use can be obtained by aerial photograph sampling analyses. Even when aerial photographs are available, however, it is an expensive and time‐consuming process to measure land use characteristics. Prediction equations that are derived from data characterized by high variability in the land use characteristics appear to be a reliable alternative to aerial photograph sampling analyses. In addition to being less expensive and time consuming the prediction equation approach can be used in generating land use estimates for future land use configurations. The prediction equations derived herein require demographic characteristics (e.g., population density and housing density) that can be obtained from census summaries or projections compiled by planning agencies and thus could be used with hydrologic models to estimate the impact of future development alternatives.
An empirical method of estimating the retention of phosphorus in lakes
Authors: Kirchner W. B. , Dillon P. J.
Published: February 2008

The relationship between phosphorus retention and several other lake and watershed parameters was examined for 15 lakes. A model relating the areal water load (qs) to phosphorus retention was proposed:Rp = 0.426 exp (−0.271qs) + 0.574 exp (−0.00949qs). This model was found to be theoretically sound, and the predicted and measured values were in close agreement (r = 0.94).