bluuebunny/crossref_metadata_2025 huggingface dataset:
A Real‐Time Hydrological Information System for Cities
Authors: Hung M. Eng Nguyen Quang , Weesakul Sutat , Weesakul Uruya , Chaliraktrakul Chavalit , Mark Ole , Larsen Lars Chr
Published: April 2005

Nowadays, many organizations collect hydrologic information for various purposes. But still, little information from the huge sources of data is made public in real time, and only a small fraction of the data is applied for real‐time decision making. Once the hydrologic data have become “historical” (the data are no longer applicable for real‐time decision making), the data are still very valuable for design and for evaluating and understanding the hydrologic environment. But if hydrological data are used only after they have become “history,” the value of the data collection is not fully used.

Before starting to disseminate hydrologic information it is important to address the following questions:

What kind of real‐time information should be shown to the public?

How and where should the real‐time information be presented to the public?

When do hydrologic data change from valuable real‐time information to less interesting (from a public point of view) historical hydrologic data?

What does it take in knowledge, technology, and hardware to provide real‐time hydrologic information?

This article discusses experience gathered from a research project in Bangkok concerning provision of real‐time rainfall data to the public through the Internet, hand‐held computers, and mobile phones. It also provides an outline of the future use of hydrologic information in real time. The potential benefits from the described framework for using the information are

a public rainfall and flood information service, like the daily weather forecast, and flood warning system

traffic information about streets that have a potential risk for flooding,

a decision support system for reducing flooding in the Bangkok area.
Reverse Osmosis, Membrane Cleaning
Authors: Ning Robert Y.
Published: April 2005

Reverse osmosis membrane cleaning has been extensively addressed over the years. Severe concentration of dissolved and suspended matter occurs when water is purified by using reverse osmosis (RO) membranes. Permeate recoveries of 50–90% correspond to 2–10‐fold concentrations in the reject brine. Precipitation or crystallization of foulants can occur in the narrow brine flow channels within the membrane elements, leading to reduced membrane flux or increased differential pressure across the system, or both. Crystallization of salts or precipitation of colloidal matter occur more toward the back end of the system, and preexisting silt and flocculated organic matter can clog the leading elements of the system.
Water Disinfection Using
UV
Radiation—A
S
ri
L
ankan Experience
Authors: Ratnayake Niranjanie
Published: April 2005

UV radiation has been established as an effective bactericide and viricide. UV radiation penetrates the cell wall and is absorbed by cellular nucleic acids. Radiation absorption prevents replication, thus killing the cell. However, the effectiveness of UV radiation in killing spore forming bacteria such as
Giardia lamblia
has not yet been established. UV radiation is not a chemical agent, so it produces no toxic residuals.

A special lamp is used to transfer electromagnetic energy to the target organism's cells. Mercury arc lamps are the most commonly used type of lamp because about 85% of the energy output is of the 253.7 nm wavelength, which is within the optimum germicidal range of 250–270 nm.

The effectiveness of radiation is a direct function of the energy dose absorbed by the organism, which is measured as the product of the lamp's intensity and the time of exposure. Intensity is the rate at which photons are delivered to the target organism. It is governed by the lamp's power, the depth of water, and the presence of substances that absorb the energy, such as suspended solids, color, turbidity, and soluble organic matter. The radiation dose absorbed by the water is the water's UV demand (which is similar to the chlorine demand) and is quantified as the absorption of UV energy (wavelength 253.7 nm) in a given depth of water. The energy dose also depends on the exposure time of the water to the UV radiation, although the required time is only seconds, rather than minutes, for effective disinfection. However, water that has high concentrations of substances like suspended solids, color, turbidity, and soluble organic matter may not receive an adequate radiation dose for effective disinfection.
Water Meter
Authors: Buenfil Rodriguez Mario O.
Published: April 2005

Most modern water‐meters act on the principle of counting the number of turns made by a small reaction turbine moved by the water as it flows through it. This is the basis of Sir William Siemens' invention, who patented his water meter (‘fluid meter’) in April 1852 (1). Until that time, water metering was not possible; several attempts had been made to devise a suitable device, but all had failed. W. Siemens also invented meters for other applications (bathometer for the depth of the sea, electric pyrometer, etc.).

Ironically, England, where meters were invented, remains until now one of the few countries where almost no houses have water meters installed. This gives an idea of the complexity and expense of installing and reading them, particularly when they are not really indispensable (the United Kingdom: has a relatively good quantity of rain and water to waste, but it is not the same in other countries).

Nowadays, water meters, instead of mechanical transmission of movements and signals (as in old clock gearing), send magnetic, electric, or digital pulses which can be stored (remote dial counter or display, data‐logger, etc.)
Quantification of Anoxia and Hypoxia in Water Bodies
Authors: Nürnberg Gertrud K.
Published: April 2005

Hypoxic conditions (dissolved oxygen, DO, concentration below saturation) are widely spread in freshwater and saline environments. Especially in recent years, anthropogenic impacts have led to severe increases in estuarine and coastal anoxia [e.g., Gulf of Mexico and European coast‐lines]. Diaz describes 44 marine areas of moderate to severe hypoxia worldwide. Hypoxia and anoxia (lack of oxygen or zero concentration of DO) may even be more established in the freshwater environment, where it can occur naturally in lakes or not and where recent increases in organic and nutrient loading and changes in water flow have increased oxygen depletion in lakes, reservoirs, and large rivers.
Tidally Mediated Changes in Nutrient Concentrations
Authors: Magni Paolo , Montani Shigeru
Published: April 2005

Freshwater runoff during ebb flow and salt water intrusion during the flood may have a major effect on short‐term changes in nutrient (ammonium, nitrate+nitrite, phosphate, and silicate) concentrations along an estuary. Time series hourly measurements conducted in a mixed‐semidiurnal type estuary (i.e., characterized by two major lower and higher tidal levels) show that these changes are a strong function of both tidal state (e.g., low vs. high tide) and amplitude (e.g., neap vs. spring tide). In particular, the changes in nutrient concentrations are higher during ebb than during flood tide and largest between the lower low tide and the higher high tide of a spring tide. Finally, the importance of investigating simultaneously different stations along the estuarine spine is highlighted, in addition to studying the nutrient distribution based on selected salinity intervals which may reflect only the conditions at a particular tidal state.
Temporal Scaling of Benthic Nutrient Regeneration in Bivalve‐Dominated Tidal Flat
Authors: Magni Paolo , Montani Shigeru
Published: April 2005

Beside light and temperature, nutrients such as ammonium (NH
4
+
‐N), phosphate (PO
4
3−
‐P), and silicate [Si(OH)
4
‐Si] are a key factor in controlling the growth, abundance, and structure of primary producers in the ocean. Hence, it is important to investigate the availability, sources, and distribution of these nutrient species, as well as their spatial and temporal scaling. Biological processes strongly influence nutrient regeneration in different marine systems. In the open ocean, an important portion of reduced N‐forms (e.g., NH
4
+
‐N), for instance, is made available
in situ
from waste products of plankton metabolism and supports the so‐called “regenerated” primary production. In coastal marine ecosystems, benthic nutrient regeneration is a major driving force in cycling biophilic elements (e.g., N, P, and Si) and abundant macrofauna, for example, dense assemblages of bivalves, it has been shown, play a major role in these processes.
Physical and Chemical Variability of Tidal Streams
Authors: Magni Paolo , Montani Shigeru
Published: April 2005

This article focuses on the variability of major hydrologic parameters of tidal streams that occur on different temporal and spatial scales within an individual estuary. Rapid changes in water temperature and salinity take place on a timescale of <1 hour, as a strong function of the tidal state (e.g., low vs. high tide) and amplitude (e.g., spring vs. neap tide). Large day–night fluctuations of dissolved oxygen (DO) concentration are also demonstrated and discussed in relation to the extent ofin situbiological processes. In addition, the variability of these parameters is evaluated seasonally at controlled low tide. Finally, the year‐round distribution of nutrient concentrations (i.e., ammonium, phosphate, silicate, and nitrate+nitrite) in low tide ebbing water is presented and compared with the variability in nutrient concentrations in the sediment porewater of an adjacent exposed sandflat.
Laboratory Experiments on Bivalve Excretion Rates of Nutrients
Authors: Magni Paolo , Montani Shigeru
Published: April 2005

Benthic nutrient regeneration may be referred to as a new availability to the water column of significant amounts of nitrogen, phosphorus, and other nutrients, as a consequence of the metabolism of organic matter by the benthos. The processes of benthic nutrient regeneration in coastal marine systems are strongly influenced by the presence of abundant macrofauna. Correct evaluation of the biogenic flux of nutrients due to the excretory activity of infaunal species is therefore an important background of information to investigate the cycling of biophilic elements (nitrogen, phosphorus, and silicon).
Deuterium
Authors: Kazemi Gholam A.
Published: April 2005

The hydrogen atom is believed to have been created during the “Big Bang” by proton–electron combinations (2). Together with an oxygen atom, it forms the water molecule and has three isotopes:
1
H (common hydrogen),
2
H (deuterium, D), and
3
H (tritium, T). Deuterium, discovered by Urey et al. (3) in 1932, is much heavier than
1
H. Common hydrogen has one proton, deuterium has one proton and one neutron, and tritium has one proton and two neutrons. Deuterium (also referred to as the heavy stable isotope of hydrogen) and common hydrogen are stable, but tritium is radioactive. In seawater, the relative abundances of hydrogen isotopes are H (99.984%), D (0.016%), and T (5 × 10
−5
%) (1). In the hydrosphere, there is only one deuterium atom per 6700 H atoms (4). Note that the arena of this article is limited to deuterium as it is a part of the water molecule. Hence, deuterium that may exist in other materials such as methane will not be dealt with here.
Hydrogen Ion
Authors: Kazemi Gholam A.
Published: April 2005

Hydrogen, the lightest of all gases, is colorless, odorless, and tasteless. Together with helium, it occupies the first period of the periodic chart of elements and is the most abundant element in the solar system. After helium, it has the second lowest boiling temperature of all elements. Because of its low boiling point, liquid hydrogen is used as a cryogenic fluid (to produce low temperatures), and because of its high heat of combustion (120 kJ/g), it is a valuable rocket fuel. Molecular hydrogen, H
2
, can combine directly with most elements. Mixtures of H
2
and O
2
can be explosive. Much of the industrial consumption of hydrogen is in hydrogenation reactions, the addition of H
2
to other molecules. Water and power are required to produce hydrogen. In its compounds, hydrogen is found in three oxidation states, +1, −1, and 0. Hydrogen is such an important element that it has its own association. The National Hydrogen Association (
WWW.Hydrogenus.org
), for example, was formed in 1989 (in the U.S.) to act as a focal point in hydrogen related matters. Anyone interested in water related matters should know the important characteristics of hydrogen because of its place in the water molecule.
Age Dating Old Groundwater
Authors: Kazemi Gholam A
Published: April 2005

First, two closely interrelated terms, groundwater age and groundwater residence time, need to be explained and differentiated. Groundwater age is the amount of time that has lapsed since the water molecule, whose age is of concern, was recharged into the system till this molecule is sampled for age‐dating. Groundwater residence time is the time it takes for a single molecule of water to travel from the recharge area to the discharge area of the aquifer, the time interval between infiltrating into, and exfiltrating out of, the subsurface media. Groundwater age and residence time are comparable to the age and lifetime of a person, respectively.

Old groundwaters may be defined as those that are too old to be dated using techniques like
3
H, CFCs,
85
Kr,
36
Cl/Cl and
3
H–
3
He. These techniques are specifically applied to age‐date young groundwater. Four methods have been in use for dating old groundwaters. In the order of the age range they can measure, these include (1)
39
Ar, (2)
14
C, (3)
36
Cl, and (4)
4
He.

The
14
C method is the most extensively used method for dating old groundwater.
14
C, also known as radiocarbon, has a half‐life of 5730 years; it can enter groundwater systems by various geochemical and biological processes.
Nitrogen
Authors: Steele Kenneth F. , Brye Kristofor R.
Published: April 2005

Nitrogen (N) is ubiquitous in the environment and in the correct form is an essential nutrient for plants and animals. About 26.5% of Earth's nitrogen is in rocks and essentially all of the remainder (73%) is in the atmosphere as an inert monotomic gas (N
2
) that comprises 78% of the atmosphere. Only a small amount of nitrogen is present in the hydrosphere and biosphere, but nitrogen is a crucial nutrient there. For nitrogen to be used by organisms, it must be in a usable form; it must be combined or “fixed” with oxygen or hydrogen. The most common fixed form of nitrogen in ground water is the anionic oxide—nitrate (NO
3
−
), and the second most common form is the cationic form–ammonium (NH
4
+
). Approximately 85% of the nitrogen in stream water is in the form of organic N and most of the rest (NO
3
−
and NH
4
+
) is derived from the decomposition of organic matter. N
2
is converted to organic nitrogen predominantly by microorganisms and certain plants. About 96% of the nitrogen in soil is bound in organic matter, and nitrate is a product of organic matter degradation. Nitrogen occurs in five oxidation states, −3, 0, +1, +3 and +5, that are primarily the result of bacteria‐induced oxidation.
Ammonia
Authors: Burgess Robert M.
Published: April 2005

Ammonia is a primary breakdown product of nitrogen‐containing organic matter in aquatic environments. Because a great deal of organic matter and waste is introduced into the hydrologic cycle by natural and anthropogenic processes, ammonia can be found in aquatic environments, especially those exposed to large amounts of human or domestic animal wastes. Ammonia is also of great importance in understanding the global cycling of several key elements, including nitrogen and carbon. Ammonia is one of the compound uniquely critical to life which when not present in adequate amounts in aquatic environments can be associated with negative biological effects and when in excess can result in adverse ecological and toxic effects. When insufficient ammonia is available to plants, which assimilate ammonia to grow, they may experience metabolic problems due to nutrient limitations. Conversely, excess ammonia is commonly associated with eutrophic conditions in water bodies and toxicity to some organisms. Further, nitrous oxide (N
2
O) a molecule involved in the environmental cycling of ammonia is considered a potential ‘greenhouse gas’ which can also destroy stratospheric ozone. Because of these adverse effects, ammonia is frequently considered a pollutant in aquatic systems.
Beryllium in Water
Authors: Clausen Jay
Published: April 2005

Numerous analytical methods are available for analyzing beryllium: inductively coupled plasma‐mass spectrometry (ICP‐MS), optical emission spectrometry (ICP‐OES), atomic absorption spectrometry (AAS), colorimetric, and fluorimetric methods (10, 11). A detailed listing of the colorimetric methods can be found in Taylor et al. (12). The preferred method for soil and water analysis in the environmental business is ICP‐MS following United States Environmental Protection Agency (USEPA) methods 200.7 and 6010. The ICP‐MS instrumentation has greater sensitivity and reduced interference from other metals, compared to other analytical methods. A typical reporting limit of beryllium in environmental investigations using the ICP‐MS method is 5 ppb; typical method of detection limits for soil and water are 0.1 µg/kg and 0.7 µg/L, respectively. AAS is also an USEPA approved process following method 7090 or 7091. Due to beryllium's low concentration and subsequent interference with other metals in environmental samples, a number of separation and preconcentration methods have been developed using chelating agents, ion‐exchange resins, sorbants, and surfactants.
Time of Concentration and Travel Time in Watersheds
Authors: Saghafian Bahram
Published: April 2005

Time of concentration is usually defined as one of the following categories:

The time that it takes for water to travel from the most distant part of a watershed to the outlet. Some literature appropriately emphasizes that the distance has a hydraulic base and not necessarily a geometric base.

The wave travel time from the most hydraulically remote point to the outlet of a watershed.

The time elapsed for which all parts of a watershed contribute to direct runoff at the outlet.

In hydrograph analysis,Tcis defined as the time between the end of excess rainfall and the inflection point on the falling limb of the hydrograph. It is assumed that the inflection point indicates the end of direct runoff. The centroid of the rainfall hyetograph is sometimes defined as the beginning ofTc.

Uncertainty in computingTcandTtrepresenting watershed time responses is due mainly to simplifications of complex rainfall–runoff processes. Watershed time response depends strongly on watershed static characteristics, such as shape, area, slope, length, roughness (neglecting long‐term changes), and drainage pattern. On the other hand, time response is a function of nonstationary factors such as spatial and temporal rainfall variations. Therefore, watershed time response is generally event‐dependent and not a stationary character of a watershed.
Water Quality in Ponds
Authors: Priyadarshi Nitish
Published: April 2005

A pond is a body of water usually smaller than a lake, encircled by vegetation, and generally shallow enough for sunlight to reach the bottom. Rotted plants can grow in any spot within the pond. Widespread plant growth, such as pickerelweed, spatterdock, and cattails, is quite common in and around ponds and aids in creating a habitat for various forms of animal life, including insects (e.g., damselflies and dragonflies), bullfrogs, greenfrogs, red winged blackbirds, marsh wrens, and bats.

The chemical composition of any pond water ultimately depends on those elements and compounds in solution, in suspension, and those accumulating along the pond bottom, most of which come secondarily to the ponds from runoff. Other substances are produced by chemical reactions between the different elements and/or compounds by vegetation growing in or around the ponds.
Watershed
Authors: Brettschneider Karen D.
Published: April 2005

Watersheds are defined by first selecting a point along a stream or river. The stream and its tributaries, if any, are then traced backward from there, and the topography of the terrain is analyzed. The watershed boundary is defined by the high point, or ridge, between streams flowing to separate major waterbodies or “stems.” All waters falling within the watershed boundary, in theory, eventually flow to the original point designated to define the watershed.
Watershed Hydrology
Authors: Black Peter E.
Published: April 2005

Consideration of a drainage basin as the basic unit of supply and management goes beyond merely calling attention to the need for watershed management based on what we typically visualize of the natural environment. This article seeks to establish a broad base for anyone who wishes to base policy decisions on sound science, in this case, on some readily identified and easily comprehended fundamentals about natural and disturbed hydrologic environments. This article organizes, defines, and explains the importance of seven basic functions of watersheds, augmented by some essential topics aimed at a more thorough understanding of the functions.
Acidification of Freshwater Resources
Authors: Geller Walter H.
Published: April 2005

All freshwater resources, groundwaters, lakes, and rivers, can be acidified. Inland waters receive acid inputs via the atmospheric path and by direct inflows from surface runoff and from groundwaters. Sources of acids are smoke from burning of fossil combustibles and from volcanoes, acidic wastewater from industrial plants, geogenic acids from weathering of sulfidic deposits at their natural sites, or from oxidation of sulfides with/after mining ores, hard coal, and lignite. Accordingly, the acid inputs into ground‐ and surface waters are either distributed by acid rain over long ranges and large areas, or they are restricted to local impacts by draining of mines, dumps, or sulfidic natural deposits. Both pathways are found in active volcanoes regionally releasing volatile acids into the atmosphere and being direct, local sources of highly mineralized acidic brines. Last but not least, freshwaters can be directly acidified by inflows of industrial wastewater. The effect of acidic inputs is larger in soft water because of the low content of ions and low buffering capacity.
Fish Cells in the Toxicological Evaluation of Environmental Contaminants
Authors: Sweet Leonard I.
Published: April 2005

Aquatic life at risk to modulation by environmental contaminants include fish and their organs, tissues, cells, and subcellular processes. Through branchial, dermal, and oral absorption, as well as biomagnification, it is highly probable that fish are exposed to many chemical species, their metabolites, and their mixtures (e.g., aromatic hydrocarbons, carbamates, heterocyclic compounds, heavy metals, organophosphates, and halogenated compounds). Sources of toxicant exposure include primary anthropogenic emissions, municipal and hazardous waste landfills, incinerators, episodic and diffuse loadings, as well as global secondary sources that involve complex cycling across air–water (e.g., deposition, rain, snow), sediment–water, and biotic interfaces (e.g., vegetation, fish, birds).

Environmental contaminants of concern require research into their accumulation potential, toxicological potency, and heath effects, because they can adversely affect aspects of fish life histories through direct effects (e.g., on developing eggs and larvae) or by more indirect means (e.g., immunosuppression, and enhanced skin and liver disease). Chemical contaminant exposure can interfere with critical phases of the cellular response by destroying, sensitizing, or otherwise altering the functions of cells.
Factors Affecting Fish Growth and Production
Authors: Viadero Roger C.
Published: April 2005

The health and subsequent growth of fish are directly related to the quality of water in which the fish are raised. In general, factors affecting fish growth and production in freshwater aquatic systems can be classified as physical, chemical/biochemical, or a combination thereof. The physical properties of water that are important to fish production and growth include temperature and the concentrations of suspended and settleable solids; important chemical parameters include pH, alkalinity, hardness, and metals.

Water temperature is one of the most important physical factors affecting fish growth and production. Fish are cold‐blooded animals which assume approximately the same temperature as their surroundings. Typically, fish are classified broadly as cold, cool, or warm water, depending on their tolerance for particular temperature ranges. Within each temperature classification, fish survival is bounded by an upper and lower temperature, between which an optimum temperature for growth exists. When temperatures vary outside the optimum range, decreased tolerance to changes in water quality constituents (particularly metabolites such as ammonia) and a decrease in immunological response can occur. Consequently, decreased growth/productivity and in some cases, mortalities, may result, depending on the magnitude of the deviation from the optimum temperature. For example, the survivable temperature range for rainbow trout (Oncorhynchus mykiss) is ∼1 to 26°C. However, depending on the reference source, the “optimum” temperature range for growth is 13 to 21°C.
Flood Control in the
Y
ellow
R
iver
B
asin in
C
hina
Authors: Li Rongchao
Published: April 2005

During the early decades of the twentieth century, flood control in the Yellow River basin has evolved as a combination of traditional management practices, influences from European‐based industrial society, and new technical and organizational features from modern Chinese society. The views on flood management were determined by the famous Chinese flood managers, Li Yizhi, Shen Yi, Zhang Hanying, and Wang Huayun. In the mid‐1950s, a multipurpose plan for permanent control of the river was initiated. This plan included the construction of more than 40 dams and projects to moderate the river's flow (and produce energy).

Today, on the upper and middle stream of the Yellow River, there are 173 large and medium‐sized reservoirs whose total storage capacity is 55.2 billion m
3
. Downstream of the Sanmenxia reservoir (see Figs. 2 and 5), two large flood retardation basins—the Beijinti and the Dongpinghu—were constructed. Their storage capacity is 2 billion m
3
each and detention area 2316 km
2
and 627 km
2
, respectively. Altogether 5000 bank protection works with a total length of 585 km were built. In this way, the flood control works can resist peak discharges of 22,000 m
3
/s (1958 flood) at the Huayuankou hydrologic station (1958 flood), corresponding to a 60‐year return period. The Xiaolangdi Reservoir whose a storage capacity is 12.65 billion m
3
on the lower reach increased the protection standard there to a return period of 1000 years.
Floodwater Spreading
Authors: Bahram Saghafian
Published: April 2005

Providing usable water resources, especially in arid and semiarid regions, is going to be one of the major challenges of the twenty‐first century. Therefore, alternatives in water resources development must be studied thoroughly as population growth increases the pressure on renewable and nonrenewable water resources. Most of the precipitation and surface runoff in areas subjected to water scarcity usually occur in seasons that do not coincide with periods of high water demand. On the other hand, growth in drinking and irrigation water demand has caused overuse of more reliable resources, such as groundwater, and has degraded their quality.

Flood spreading is a practical water and soil conservation technique that, if designed and maintained properly, can address one or a combination of water‐related issues on local scales. Such issues may involve reduction of flood damage downstream by diverting a portion of the flood volume, controlling sheet and gully erosion over the land by maintaining vegetation cover, storing water in the soil profile or in underground aquifers for future use, improving soil fertility through sediment deposition, leaching saline soils, and irrigating cultivated and cropped lands where the rainy period and the growing period nearly coincide. The suitability and success of a flood spreading system depends on the project objective(s), nature of the soil, amount and temporal distribution of precipitation, land topography, and water demand.
Forensic Hydrogeology
Authors: Leonhart Leo S. , Hargis David R.
Published: April 2005

Forensic hydrogeology is a branch of environmental forensics, a relatively new discipline involving the use of environmental science to support litigation.

Due to the technical complexities of many legal matters pertaining to environmental issues, hydrogeologists often find themselves as members of interdisciplinary litigation support teams. These teams may comprise other experts in fields such as toxicology, chemistry, microbiology, engineering, industrial hygiene and safety, regulatory compliance, and industrial history and standards. Typical tasks for hydrogeologists include delineation of the source(s) and extent of contamination in subsurface soils and groundwater, interpretation of subsurface conditions controlling such flow and transport, analysis of groundwater flow and contaminant transport, determination of risk pathways toward potential receptors, and feasibility assessment of various remedial alternatives.

There are forensic applications in hydrogeology that involve litigation, but which do not involve contamination or toxic tort matters. Examples include settlement of damages between parties involving water supply issues, such as well interference or interruption of baseflow; flooding, such as watershed or hydrographic modifications resulting in increased runoff; or simply well drilling and design, involving poor yields or failures.
Geochemistry of Acid Mine Drainage
Authors: Viadero Roger C.
Published: April 2005

Acid mine drainage (AMD) results when metal pyrites come in contact with water and/or air, to form dilute sulfuric acid. For instance, iron pyrite (FeS2) is the major iron‐sulfur impurity found in mined earth, particularly in the eastern United States where coal mining is prevalent. Typically, AMD waters contain elevated concentrations of SO4, Fe, Mn, Al, and other metal ions. As an example, representative AMD water quality parameters from the Roaring Creek‐Grassy Run Watershed, located in Elkins, West Virginia, include pH from 2.4 to 3.3, mineral acidities from 2.4 to 980 mg/L as CaCO3, dissolved iron between 35 and 260 mg/L, and sulfate concentrations from 190 to 740 mg/L.

In contrast, copper and arsenic sulfide compounds associated with “hard rock” mining operations are common in the western United States; such compounds are generally much less prevalent in the east. In such instances, sulfide containing minerals such as pyrrhotite (FeS), arsenopyrite (FeAsS), and chalcopyrite (CuFeS2) can produce acidic drainage when oxidized.
Kinematic Shock
Authors: Singh Vijay P.
Published: April 2005

Kinematic shocks form due to a variety of factors, including spatial and temporal variability of inflow, systems geometry, and initial and boundary conditions. This study provides a short overview of the formation, propagation, tracing, and fitting of shocks in hydrologic modeling, in particular, referring to rainfall–runoff modeling.

The kinematic shock is a discontinuity representing a sudden rise or surge in flow depth. For example, flood waves have an intrinsic tendency to steepen as they propagate downstream due to lateral inflow or geometric constriction and eventually form a shock. The discontinuity can also represent a sudden decrease in flow depth. For example, when flow advances over a porous bed, there comes a time when the flow rate is not sufficient to satisfy the infiltrating demand of the bed and is, therefore, suddenly absorbed by the bed. This phenomenon is observed in ephemeral streams and irrigation borders and furrows. Discontinuities in flow are also observed in geologic formations due to fracture, fissures, and sudden changes in porous media properties. Shocks are also observed in landscape evolution and formation of deltas, river bed profiles, and river junctions.
Kinematic Wave and Diffusion Wave Theories
Authors: Singh Vijay P.
Published: April 2005

A wide range of phenomena, natural as well as man‐made, in physical, chemical, and biological hydrology exhibit characteristics similar to those of kinematic or diffusion waves. The wide range of phenomena suggests that these waves are very pervasive. This study presents theories that are considered fundamental to advancing the state of the art of hydrology.

The term “wave” implies a disturbance traveling upstream, downstream, or remaining stationary. We can visualize a water wave propagating where the water itself stays very much where it was before the wave was produced. We witness other waves that travel as well, such as heat waves, pressure waves, and sound waves. There is obviously the motion of matter, but there can also be the motion of form and other properties of matter.
Kinematic Wave Flow Routing
Authors: Singh Vijay P.
Published: April 2005

Flow routing on planes, in channels, and in storm sewers using the kinematic wave theory is quite popular, especially for urban drainage design and planning. The small watershed sizes and the often fairly steeper prismatic conduits in an urban environment are well suited for application of the theory. Little or no stream‐flow data are required to develop the kinematic wave routing method. In nonurban environments, the kinematic routing wave method, corrected for dynamic effects, is also becoming increasingly popular.
Lakes
Authors: Geller Walter
Published: April 2005

Lakesare waterbodies of considerable size that are larger than ponds.Shallow lakesare mixed by the wind from the surface to the ground, and the daylight reaches the bottom.Stratified lakesare deep enough to be vertically divided into a lighted surface‐neareuphoticzone, where photosynthesis of green plants is possible, and a deep‐wateraphoticzone, which is too dark for photosynthetic activities. In many lakes, thermal vertical stratification is observed as a warm layer near the surface, the epilimnion, and a colder layer below, the hypolimnion. The epilimnion is wind‐exposed and well mixed, whereas the deep water layer of the hypolimnion is not included in the mixis process.

Lake basins containing standing waterbodies were formed by different processes; tectonic forces; volcanic, glacial, fluviatile activities; or by solution of easily dissolvable rock such as limestone.
Modeling of Urban Drainage and Stormwater
Authors: Mark Ole , Weesakul Sutat
Published: April 2005

The construction and operation of urban drainage and stormwater systems have historically been driven by the objectives of maintaining public hygiene and preventing flooding. All over the world, cities have grown rapidly during the last century, and city authorities have built and continuously expanded storm and wastewater drainage facilities. Many old cities have developed according to their varying historical needs and visions. Hence, the layout and design of the infrastructure have gradually developed into rather complex systems, which require tools to handle such situations.

An understanding of the physical system and its interaction with the environment is a prerequisite for effective planning and management of urban drainage and stormwater systems. In this respect, computer models provide the opportunity for well‐structured analyses of the current performance of a system and the effect of potential changes in the system; they offer a sound scientific framework for coordinated management and planning. Apart from assessing different scenarios, the models also help to improve process understanding. Urban drainage models are used to understand the often rather complex interaction between rainfall and overflow/flooding. Once the existing conditions have been analyzed and understood, alleviating schemes can be evaluated, and the optimal scheme implemented.

Today's advances in computer technology allow many cities all over the world to report overflows from their sewers yearly using a combination of measurements and modeling, and in many places, they manage local and minor flooding problems using computer‐based solutions. This involves developing computer models of the drainage/sewer system, for instance, by using software such as InfoWorks, MIKE URBAN, MOUSE, PCSWMM, and SWMM. All are hydrodynamic modeling packages that solve the one‐dimensional equations of St. Venant.
Modeling of Water Quality in Sewers
Authors: Mark Ole
Published: April 2005

Modeling of water quality in sewers emerged during the late 1990s. The water quality and amount of water in sewers are dominant factors for designing wastewater treatment plants and for analyzing water quality impacts from sewer overflows. In addition, sewage under anaerobic conditions may cause corrosion of pipes, malodors, and pose health risks for sewage workers. Hence, it is of utmost importance to analyze and understand the transport and transformation of wastewater in sewers. Ideally, modeling of sewer systems and wastewater treatment plants should be based on the same general principles and done in integrated models to pursue an integrated understanding and management of sewers, wastewater treatment plants, and receiving waters. However, it must be stressed that the transformation of wastewater in sewers is not identical to the processes in activated sludge and biofilm systems—so even though several similarities exist between sewers and wastewater treatment plants, modeling of water quality in sewers is a discipline of it own. This article focuses on how to model water quality in sewers.
Biotic Integrity Index to Evaluate Water Resource Integrity in Freshwater Systems
Authors: Wang Lizhu , Weigel Brian B.
Published: April 2005

Many varied and complex environmental problems, particularly row crop and grazing agriculture, urbanization, highway building, timber harvesting, and water projects such as dams, water withdrawals, and stream channel modifications have seriously affected the health of freshwater resources in many parts of the world. The health of aquatic resources can be measured in many ways. Among them, biotic (or biological) integrity is a concept most commonly used by the public, biologists, resource managers, and policy makers to measure the status of aquatic systems.

Biotic integrity is “the capability of supporting and maintaining a balanced, integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of natural habitat of the region.”

Aquatic systems of high biotic integrity have a biological community in which composition, structure, and function have not been seriously altered by human activities. Such systems can withstand or rapidly recover from some perturbations imposed by natural environmental processes and survive many major disruptions induced by humans. Aquatic systems that lack integrity are often degraded and when further perturbed by natural or human‐induced events are likely to change rapidly to an even more undesirable status.
An Outline of the History of Fishpond Culture in
S
ilesia, the Western Part of
P
oland
Authors: Szumiec Maria A.
Published: April 2005

The need for pond construction in Silesia arose from the lack of large natural waterbodies and the long distance to the sea. The abundance of water, benign climate, fertile soils, the growing demand for fish in the developing towns; and the possibility of transporting fish along the rivers favored the development of fish farming.

The first development and breakdown of fishpond culture occurred between the twelfth and middle of the fifteenth century. Probably, Cistercians began to breed fish in ponds in the eleventh or twelfth century. Fishpond farming developed after the rivers and natural waterbodies had been wastefully exploited owing to the increasing population and strict observance of fasting. The highest progress in fish farming occurred in the fourteenth century and resulted from a rapid economic progress accompanying the growing mining industry and developing trade. Numerous fishponds as well as the introduction of the carp, probably from Czech and Moravia, allowed people to meet the religious demands.

The fish from Upper Silesian ponds were transported by the River Vistula to Cracovia the capital of Poland where the king's court and an increasing number of citizens created high demand for fish. In some estates, the income from pond farming was estimated at 50–60% of total income.

Pond complexes also alleviated and prevented frequent freshets and floods in mountainous regions where forests disappeared owing to developing ferrous metallurgy. In periods of drought, pond waters were used to irrigate fields. Ponds were also built to reclaim marshy sites and to increase the area of cropland and meadows.
Potential Health Issues Associated With Blue‐Green Algae Blooms in Impoundments, Ponds, and Lakes
Authors: Rosen Barry H.
Published: April 2005

Cyanobacteria, also known as blue‐green algae, are the most primitive group of algae. Although they are most closely related to other bacteria, they have the same pigment for photosynthesis that other algae and plants have. They are simple but remarkably successful organisms. Individually, they are microscopic; however, large clusters of cells are easily visible as a surface scum (a type of algal bloom) on any stable body of water. Some kinds of blue‐green algae produce natural toxins. Unfortunately, no visual technique can distinguish between toxin‐producing blue‐greens and those that are harmless. Ingestion of these toxins has caused the poisoning of domestic animals, sometimes resulting in death. These include cattle, horses, sheep, hogs, ducks, dogs, and wildlife. Human exposure and toxicity, ranging from intestinal problems to liver damage and fatalities has only recently been documented.
Reliability Concepts in Reservoir Design
Authors: Koutsoyiannis Demetris
Published: April 2005

A reservoir's function is to regulate natural inflows, which vary irregularly, to provide outflows at a more regular rate that is determined by water demand for one or more uses (water supply, irrigation, hydropower), temporarily storing the surplus, when inflows exceed outflows. Reservoir reliability is defined as the probability that the reservoir will perform the required function, i.e. provide the outflow required to satisfy the water demand, at a specified period of time under stated conditions. The traditional reservoir design procedures are more commonly based on empirical approaches. It is shown, however, that the reliability concept is a more rational basis, and provides easy and accurate computational procedures, for reservoir design and operation. Under some simplified assumptions, a simple explicit expression relating reservoir size, yield and reliability is extracted. This expression can be used for preliminary stages of a reservoir design. For more detailed and accurate studies, a generalized solution procedure based on stochastic simulation of inputs is outlined.
Reservoir Sedimentation
Authors: Jain Sharad K.
Published: April 2005

The detachment and transportation of soil is termed soil erosion. Every stream carries some sediment in suspension and moves larger particles along its bed. The deposition of sediment in channels or reservoirs creates a variety of problems, such as raising stream beds, meandering and overflow along the banks, and, of course, depletion of storage capacity in reservoirs.

The sediment content in river waters varies with flow conditions. It is small in lean flow months, but it attains a maximum value during floods. The total quantity of sediment transported annually to the sea by rivers of the world is about 2 × 10
10
tons or about 13.5 km
3
in volume. Worldwide, reservoirs are annually losing about 1% of their storage capacity or about 65 km
3
/year. The rate of loss of reservoir storage in the United States is about 0.22%/year which is equivalent to 2020 million m
3
/year. Based on weighted average data from 144 reservoirs in India, the annual loss of gross storage was estimated at 0.44%.

Sediment source and reservoir locations are not uniformly distributed; the problem is really severe in some countries. China has more than 80,000 reservoirs that are annually losing, on average, 2.3% of their storage capacity due to sedimentation.
Riparian Systems
Authors: Endreny Theodore A.
Published: April 2005

Riparian areas are those along the bank of a watercourse, which is a relatively narrow transition zone between a downslope aquatic waterbody and an upslope terrestrial watershed. Riparian areas are predominantly associated with a river or stream, but also define the bank of a lake, wetland, or other standing water. The riparian system refers to the atmospheric, vegetation, and soil components; their physical, chemical, and biological properties; and their interaction with each other and the upslope terrestrial and downslope aquatic hydrologic cycle. It is important to recognize that riparian areas may border both influent and effluent streams, known as those that lose or gain water to the groundwater.
Cienega
Authors: Leonhart Leo S.
Published: April 2005

Cienega is both a hydrologic and ecological term used primarily in the southwestern United States and northwestern Mexico to designate a riparian marshland. The term cienega derives from the Spanish phrasecien aguas(literally “hundred waters” or more figuratively, “place of one hundred springs”). The modern Spanish equivalent isciénaga(“marsh, swamp”).

Most often, the term cienega refers to broad riparian areas of slowly flowing or ponded water, populated by dense vegetation. Such hydrologic conditions are unique in the Southwest because of the limited and declining number of perennially flowing stream reaches in the arid Southwest. Cienegas may also result from the discharge of springs or other conditions involving shallow or discharging groundwater. The term has also been applied to more diverse aquatic habitats throughout areas of Hispanic influence.
Sediment Load Measurements
Authors: Erskine Wayne D.
Published: April 2005

Two modes of sediment transport by rivers, suspended load and bed load, are usually recognized on behavioral grounds.Suspended loadrefers to the relatively fine part of the total sediment load that is transported in continuous or intermittent suspension. For sediment to remain in suspension, flow turbulence and velocity must be sufficiently great to counter the tendency of suspended sediment to settle to the riverbed. The two main factors determining sediment settling velocity are grain size and density.Bed or traction loadrefers to the relatively coarse part of the total sediment load that is transported along or close to the riverbed by rolling, sliding, or saltation. The latter term refers to sand movement in a series of hops across a riverbed in a distinct, concentrated layer.