bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infiltration and Soil Water Processes
Authors: Holden Joseph 
Published: April 2005

Abstract
Water at the soil surface is drawn into the soil pores under the influence of both suction and gravity. Suction (or tension/capillary) forces are largest in the small pore spaces between soil particles. Therefore, small pores fill first, and large pores empty first. As a soil becomes saturated, suction forces approach zero. As a soil dries, suction forces dominate, and there is little or no gravitational flow. For a dry soil during the early stages of wetting, the effect of soil pore suction is predominant. However, as the depth of wet soil increases, the suction gradient decreases (the same difference in suction is spread over an ever increasing depth interval) and the gravitational head gradient becomes the main driving force.
Infiltration processes cannot easily be separated from the processes involved in movement of water within soil because the rate of infiltration is partly controlled by the rate of soil water movement below the surface. Soil water movement continues after an infiltration, as the infiltrated water is redistributed. Infiltration and soil water processes play a key role in surface runoff, groundwater recharge, ecology, evapotranspiration, soil erosion, and transport of nutrients and other solutes in surface and subsurface waters.
Karst Hydrology
Authors: Bednar David M. 
Published: April 2005

AbstractThe most interesting aspect of a karst landscape is its unique hydrologic system. Karst landscapes are primarily underlain by carbonate, primarily limestone and dolomite, where surface water and groundwater are interconnected to form one functional unit. The end result of this hydrologically integrated flow system is the karst spring. Springs provide substantial quantities of water for human consumption and commercial enterprises. Because karst aquifers provide effective natural cleansing, it is imperative to understand the dynamic flow systems within these aquifers to protect these vulnerable water supplies from contamination.
Karst Topography
Authors: Bednar David M. 
Published: April 2005

Abstract
Karst is an irregularly shaped area of land where underground drainage dominates and has resulted in dissolving the bedrock to form distinctive surface and subsurface features. Karst predominately develops on lands underlain by soluble bedrock such as limestone and dolomite, but can also form in marble, gypsum, and halite. Due to differences in climate, cover, rock type, hydrology, and geologic structure, some areas show significant expression of karst development at the surface, and others show no obvious signs at all. Chemical solution of the bedrock by groundwater leads to the formation of open passageways into and through the subsurface. The degree of development of these features varies greatly from one region to another.
Lysimeters
Authors: Brye Kristofor R. 
Published: April 2005

Abstract
Lysimetry is a measurement technique that employs sampling devices called lysimeters to measure the movement of water and solutes through a porous medium. Lysimeters have most commonly been used to quantify water movement (i.e., drainage) through soil and typically consist of a porous plate surface of varying pore sizes through which water moves from the soil into a collection reservoir.
Methane in Groundwater
Authors: Priyadarshi Nitish 
Published: April 2005

Abstract

Methane is a colorless, odorless, and tasteless gas, which is produced by biological decay of organic materials or by high temperatures acting on organic materials in unconsolidated and geologically young deposits. These materials include coals, organic rich shales, landfill materials, compost piles, and other accumulations of organic materials both above and underground. For example, a buried oak log, only 1 ft in diameter and 5 ft long, can generate enough methane when it decomposes underground to form an explosive mixture in 400 to 1200 m
3
of air (1).

Methane is produced by biological processes where oxygen is excluded (anaerobic conditions). Methane can be oxidized in water that contains dissolved oxygen, so the amount that reaches the surface depends on the depth of water. Its rate of production generally increases with temperature.
Nitrate Contamination of Groundwater
Authors: Azadpour‐Keeley Ann , Keeley Jack 
Published: April 2005

Abstract
Groundwater supplies drinking water for half of the people in the country and represents the total water supply for many of the western states. Numerous contaminants are anthropogenic, including petroleum products, chlorinated solvents, and pesticides, but nitrate contamination can be either natural or man‐made and is one of the most common chemical contaminants of groundwater. Nitrate levels in uncontaminated groundwater are generally less than 2 mg/L, but levels have been increasing during the past five to six decades in areas where contamination has occurred.
Nonpoint Sources
Authors: Jain Chakresh K. 
Published: April 2005

AbstractIn recent years, it is being recognized that the nonpoint sources of water pollution have greater importance than point sources. This is due in part to the continuing efforts to reduce pollution from point sources during the past few decades, as well as recognition that nonpoint sources, such as storm water, may contain harmful contaminants. Modern agriculture has also relied, among other things, on heavy use of fertilizers and pesticides. This has largely occurred without any serious regard to the environmental consequences, especially pollution of both surface and groundwater resources. Chemicals (fertilizers and pesticides) applied in agroecosystems invariably enter the hydrologic cycle and contaminate both surface and groundwater resources. Nutrients and pesticides, particularly, are of major concern because of eutrophication and toxicity. Nutrients and pesticides are transported from cropland either by being absorbed onto eroded soil particles or dissolved in runoff water. This has increased the need to identify and quantify major sources of nutrients and pesticides deposited within river systems. In this article, some basic concepts of nonpoint source pollution, including the effects and extent of pollution in surface and groundwater bodies, pollution control measures, monitoring and modeling approaches, and management options are presented.
Perched Groundwater
Authors: Leonhart Leo S. 
Published: April 2005

Abstract

Perched ground water is subsurface water that forms a saturated horizon within porous media at an elevation higher than the local or regional groundwater table. This condition may result from various field conditions, but the requisite condition is a soil or rock horizon of significantly lower vertical hydraulic conductivity (
K
v
) (perching unit) amid contrastingly higher
K
v
strata. Downward movement of infiltrating water through the higher
K
v
materials is retarded and accumulates above and/or within the perching unit. This typically “mounds” saturated water above the perching unit, leaving an unsaturated (vadose) horizon below the perching unit. The upper limit of saturation in a perched zone is referred to as a perched water table, whereas the lower limit has been defined as an inverted water table.
Permeability
Authors: Priyadarshi Nitish 
Published: April 2005

Abstract

Permeability is a measure of the ease with which fluids pass through a porous medium. It was established experimentally by Darcy in 1856 that

urn:x-wiley:9780471478447:media:gw826:xm1

in which
k
is the permeability,
Q
is the volume of fluid which passes in unit time through area
A
in the direction
s
of the pressure gradient d
p
/d
s
, and
n
is the viscosity of the fluid. The unit of permeability in most common use by geologists and members of the oil industry is the darcy (D), which corresponds to a flow of 1 cm
3
s
−1
cm
−2
at a pressure gradient of 1bar cm
−1
. If the fluid is water, material with a permeability of 1D will pass 10
−3
cm
3
s
−1
cm
−1
at a pressure gradient of 1 g cm
2
cm
−1
.
Phytoremediation of Selenium‐Laden Soils
Authors: Datta Rupali , Sarkar Dibyendu 
Published: April 2005

Abstract

Selenium (Se) is a naturally occurring metalloid that is toxic at high concentrations but is also a nutritionally essential element. In the 1980s, Se‐contaminated water at the natural wildlife refuge at Kesterson Reservoir, California was responsible for widespread reproductive failure, developmental defects, and death in migratory aquatic birds and fish. The environmental and health impacts of this incident have resulted in extensive research on the behavior of Se in soils and plants. The cost of using conventional remediation technologies for cleaning up Se‐contaminated soils is very high, so recent research has focused on phytoremediation of Se from contaminated soils. Selenium accumulation by plants and its subsequent volatilization are very effective in remediating Se‐contaminated soil and water. Natural hyperaccumulator plants such as
Astragalus
growing in seleniferous soils accumulate high concentrations of Se in their tissues. However, the main drawback of using these plants for phytoremediation is their slow growth rate and low biomass. This has prompted researchers to investigate the possibility of developing genetically engineered plants with better Se phytoextracting capacity. Understanding the speciation and bioavailability of Se in soils and the biochemistry of Se in plants and microorganisms is the first step toward developing effective phytoremediation strategies for Se‐laden soils.
Recharge in Desert Regions Around the World
Authors: Uhlman Kristine 
Published: April 2005

Abstract
Following Potter's classification, arid and semiarid regions are those whose precipitation to evaporation (P/E) ratios are smaller than 0.5 and between 0.5 and 1.0, respectively. In addition to a lower net precipitation rate, rainfalls are typically infrequent and of short duration; high‐intensity seasonal storms contribute a major portion of the annual rainfall over short periods of time. Under these conditions, the shallow soil surface layer infiltration capacity may be exceeded and excess overland flow propagates rapidly to flash flooding. Even low‐intensity rainfalls, can lead to significant surface runoff when desert soil crusts have formed.
Water focused and concentrated by topography into ephemeral washes, wadis, sabkhas, and playas provides locations of enhanced recharge in arid areas. A significant component of recharge to arid basin aquifers occurs along mountain fronts. Important aspects along the mountain front include the partitioning of rainfall and snowmelt into surface runoff, deep infiltration along fractures and faults, and vegetation‐controlled evapotranspiration. Focused flow along mountain stream channels into the major washes in the Tucson Basin (Arizona) visibly infiltrates flood‐plain sediment, and surface water commonly does not leave the watershed. Half the annual recharge of 9 to 10 mm/year to the Ogallala Aquifer in the southern High Plains (Oklahoma and Texas) occurs through playa floors that cover only 6% of the aquifer land surface area.
Polycyclic Aromatic Hydrocarbons
Authors: Ashworth Samuel C. 
Published: April 2005

AbstractPolycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds that have two or more fused aromatic rings. They have relatively low solubility in water and are highly lipophilic. The term polycyclic organic matter (POM) defines a broad class of compounds that generally includes all organic structures that have two or more fused aromatic rings. Polycyclic organic matter has been identified with as many as seven fused rings and, theoretically, millions of POM compounds could exist; however, only about 100 species have been identified and studied, and typically only a small fraction of them are regularly tested for as part of emissions measurement programs. Any effort to quantify emissions of POM relies on the group of compounds or analytes targeted by the test method employed. The EPA has defined these eight major categories of compounds in the class known as POM.polycyclic aromatic hydrocarbons (PAHs);aromatic hydrocarbons that contain nitrogen in a heterocyclic ring;aromatic hydrocarbons that contain a carbon–nitrogen double bond (CNH);aromatic hydrocarbons that contain a one‐ring carbonyl divalent group (CO), also known as quinones; contain two‐ring carbonyl divalent groups;carbonyl arenes that contain hydroxy groups and possibly alkoxy or acyloxy groups;oxa arenes are aromatic hydrocarbons that contain an oxygen atom in a heterocyclic ring; thia arenes are aromatic hydrocarbons that contain a sulfur atom in a heterocyclic ring; andsome polyhalo compounds, such as polychlorinated dibenzo‐p‐dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), may be considered POM although they do not have two or more fused aromatic rings.
Water Treatment in Spent Nuclear Fuel Storage
Authors: Ashworth Samuel C. 
Published: April 2005

AbstractSome of the variables that affect the growth of microorganisms include food/nutrient availability, temperature, pH, biocide concentrations, radiation, makeup water microorganism concentration, and predation. There are practical limitations to the types of activities that can be used to control microorganisms, for example, restricting the use of biocides or pH out of the range of water chemistry requirements.The first substances on a surface during biofilm formation are trace organics (2). Almost immediately after the clean pipe surface comes into contact with water, an organic layer deposits on the water/solid interface (3). These organics form a conditioning layer that neutralizes excessive surface charge and surface free energy that may prevent a bacterial cell from approaching near enough to initiate attachment. In addition, the absorbed organic molecules often serve as a nutrient source for bacteria.
Economics of Industrial Water Demands
Authors: Renzetti Steven J. 
Published: April 2005

Abstract
This article examines what is known regarding the economic characteristics of industrial water use. Understanding the economic dimension of industrial water use is important for several reasons. First, in some countries, industrial water use is already an important part of total water use. Furthermore, in a number of countries, the proportion of total water use accounted for by industry is rising rapidly. Second, much of industrial water use results in significant alterations in water quality. Third, industrial water use differs from water use in other sectors because many firms recycle water and because many firms may choose their source of water supply.
Water Use in Energy Production
Authors: Inhaber Herbert 
Published: April 2005

AbstractThe United States uses far more water to produce energy and electricity than any other sector. A slight reduction in water use in the electricity sector would far outweigh other modes of saving—toilets using less water, low‐flow shower heads,—in the household sector.Most attention here will be devoted to thermoelectric and hydroelectric plants. Thermoelectric plants can be divided into fossil fuel—coal, oil, and natural gas—and nuclear. These constitute almost all the electricity producers in this country. Water use is usually defined and measured in terms of withdrawal or consumption. The former is what is taken, and the latter is that which is used up. Water withdrawal in energy production is much greater than consumption. In hydroelectric plants, far more water is used than in any other energy source. However, the amount of water consumed—that is, not available for further use—is a small fraction of the water used and is attributable to evaporation from lakes behind hydro dams. Energy consumption for thermoelectric plants is of the order of 2% of water used.Some of the water used to produce energy becomes contaminated with pollutants. This aspect of energy production is not discussed in this article; it is treated in detail in other articles in this publication.
Energy Dissipation
Authors: Bott T. R. 
Published: April 2005

Abstract
Many process industries, such as oil refining or chemical manufacture, need to cool products or intermediate streams that may be either liquids or gases, before storage or further processing. To conserve heat and hence costs, it is usual to transfer as much heat energy as possible from an outgoing “hot” stream to an incoming cold stream or intermediate. However as the temperature of the “hot” stream is reduced, there comes a point where it is no longer economical or feasible to reduce the temperature of the stream to be cooled by further interchange of heat. As the temperature of the “hot” stream approaches the temperature of the incoming stream, the temperature driving force for heat transfer is reduced so that a relatively large heat transfer area is required to complete the cooling process. In general, naturally occurring water has a relatively low temperature and because there is so much of it in the world—in seas, lakes, rivers, canals, and boreholes—water is used as a universal cooling medium. The increasing world shortage of water, however, requires effective water management to conserve supplies and to protect the environment.
Industrial Cooling Water—Biofouling
Authors: Bott T. R. 
Published: April 2005

AbstractThe accumulation of living matter in cooling water systems may be the result of the activity of microorganisms such as bacteria, algae, and fungi, or the growth of macroorganisms that include mussels, barnacles, hydroids, and serpulid worms and plant material such as water weeds. The extent of the deposition of both micro‐ and macroorganisms, depends very much on the origin of the water employed in the cooling water circuit. In general, the water is taken from a natural source, which contains the organisms and nutrients to sustain life and growth. Some sources, such as borehole water, are relatively free of organic material, but in “open” cooling water circuits, it rapidly becomes contaminated from contact with the atmosphere. Water from other sources, including freshwater rivers, canals or lakes, estuarine or seawater, is already heavily contaminated before it is taken into an industrial system.
Evapotranspiration
Authors: Payero Jose O. 
Published: April 2005

AbstractLiquid water from a surface can be transformed into water vapor by either evaporation or by transpiration.Evaporationis the process for converting liquid water to water vapor and removing it from the evaporating surface.Transpirationis the vaporization of water contained in plant tissues and the removal of vapor to the atmosphere through leaf stomata. Evaporation and transpiration occur simultaneously in cropped surfaces, and there is no easy way of quantifying the magnitude of each component. For practical applications, such as irrigation scheduling and irrigation system design, it has been more useful to consider both processes combined. The combination of these two processes is calledevapotranspiration. The proportion of each component in a cropped surface is affected by factors such as vegetative cover, available water in the soil, and surface wetness. For an annual crop like corn, evaporation is the dominant component of evapotranspiration at the beginning of the season when the soil surface is exposed to solar radiation. As the crop grows and the canopy covers the surface, evaporation is minimized, and transpiration becomes the dominant component.
Hydrosphere
Authors: Araya Yoseph Negusse 
Published: April 2005

Abstract

The hydrosphere [Greek
hydor
water and
sphera
sphere] refers to the water on or surrounding the surface of the globe, as distinguished from those of the lithosphere (the solid upper crust of the earth) and the atmosphere (the air surrounding the earth). More specifically, the hydrosphere includes the region that includes all the earth's liquid water, frozen and floating ice, water in the upper layer of soil, and the small amounts of water vapor in the earth's atmosphere. The hydrosphere is the major setting for the earth's hydrologic cycle [see H
YDROLOGIC
C
YCLE
].

The earth's water has six major reservoirs in which water resides. These include the oceans, the atmosphere (split into two reservoirs, one over the land and one over the oceans), surface water (including water in lakes, streams, and the water held in the soil), groundwater (water held in the pore spaces of rocks below the surface), and snow and ice.
The quality of natural water in the various reservoirs of the hydrosphere depends on a number of interrelated factors. These factors include geology, climate, topography, biological processes, land use, and the time for which the water has been in residence.
Monsoon
Authors: Holst Arthur M. 
Published: April 2005

Abstract
Cyclic air masses accompanied by either much or little rain, carried by winds that reverse direction semiannually, are called monsoons. The word monsoon comes from the Arabic word “mausim,” which is translated as “season.” Monsoons occur over almost every continent, but they come in varying degrees of strength, as judged by rainfall production and wind speed. The most powerful and well‐known monsoons occur in India and Southeast Asia.
Chinook
Authors: Holst Arthur M. 
Published: April 2005

Abstract
Wind is defined as the movement of air. Although we commonly define wind as a gentle breeze or a harsh gust of cold air, there is a wind phenomenon that can increase the temperature instead of lowering it. It is called a Chinook wind. Chinooks are most commonly associated with the Rocky Mountain range in North American but can also be found in the Swiss Alps and the Andes. They can increase temperatures high enough to melt the snow in their path as they travel down the mountainside. The Chinook wind falls under the classification of katabatic wind, which means that it moves downhill.
Radar Use in Rainfall Measurements
Authors: Endreny Theodore A. 
Published: April 2005

Abstract
Meteorologists, hydrologists, and other environmental scientists use microwave radar (radio detection and ranging) techniques to observe remotely the location, type, and intensity of atmospheric precipitation. Doppler radar units provide an additional measurement of storm movement and wind rotational strength. Hence, microwave radar units are used for remotely sensing precipitation and winds.
Radar operates by emitting electromagnetic radiation into the air at various scan heights and then detecting the part of that radiation that is reflected back by hydrometeors (e.g., backscattered) to the radar device and considered reflectivity. Hydrometeors refer to liquid and frozen precipitation, but backscattering can also occur from large flocks of birds, insects, and other large airborne particles. Based on the density, size, and shape of the hydrometeors (e.g., spherical liquid vs. angular frozen crystals) and the polarization of the radar beam, the algorithms processing the radar signal can determine precipitation type and intensity.
Rain Simulators
Authors: Holden Joseph 
Published: April 2005

Abstract
There are two rainfall simulator systems: spray nozzles (including rotating sprays) and drip‐screens. Spray systems generally supply rainfall in pulses to the ground, and rotating sprays deliver rainfall across a large surface area although intensity usually decreases with distance from the rotating nozzle. The spray‐type systems often provide rainfall at terminal velocities which approach that of natural rainfall. Drip systems use hypodermic syringes or other drop formers across a fixed grid to produce rainfall across relatively small surface areas. The drop formers are often not raised high enough to allow representative terminal velocities, but they generally allow a constant rainfall rate whose drop sizes are more easily controlled than in the spray systems.