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Articles 901 - 930 of 1042

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Monitoring The 1996 Drought Using The Standardized Precipitation Index, Michael J. Hayes, Mark D. Svoboda, Donald A. Wilhite, Olga V. Vanyarkho Jan 1999

Monitoring The 1996 Drought Using The Standardized Precipitation Index, Michael J. Hayes, Mark D. Svoboda, Donald A. Wilhite, Olga V. Vanyarkho

National Drought Mitigation Center: Faculty Publications

Droughts are difficult to detect and monitor. Drought indices, most commonly the Palmer Drought Severity Index (PDSI), have been used with limited success as operational drought monitoring tools and triggers for policy responses. Recently, a new index, the Standardized Precipitation Index (SPI), was developed to improve drought detection and monitoring capabilities. The SPI has several characteristics that are an improvement over previous indices, including its simplicity and temporal flexibility, that allow its application for water resources on all timescales. In this article, the 1996 drought in the southern plains and southwestern United States is examined using the SPI. A series …


Observations On Groundwater Recharge In The Westdale Catchment, M F. Lewis, C E. Mcconnell Dec 1998

Observations On Groundwater Recharge In The Westdale Catchment, M F. Lewis, C E. Mcconnell

Resource management technical reports

A study of the role of groundwater carriers and barriers in controlling salinity was carried out in the Westdale Catchment by Lewis and McConnell (in preparation). Although that study was primarily concerned with groundwater flow and discharge processes, the data collected also provided rudimentary information on the timing of groundwater recharge events and their distribution across the landscape.


Vulnerability And Use Of Ground And Surface Waters In The Southern Mississippi Valley Region, H. Don Scott Sep 1998

Vulnerability And Use Of Ground And Surface Waters In The Southern Mississippi Valley Region, H. Don Scott

Arkansas Water Resources Center Technical Reports

There is a concern in the Southern Mississippi River Valley of the United States over non-point source pollution of ground and surface waters resulting from activities associated with agricultural production. This agriculturally intensive region consists of two major land resource areas (MLRAs): Southern Mississippi Valley Silty Uplands (MLRA 134) and the Southern Mississippi Valley Alluvium (MLRA 131). Both MLRAs have level to undulating and rolling topography, relatively fertile soils and a climate particularly conducive for row crop production.


How To Reduce Drought Risk, Cody Knutson, Mike Hayes, Tom Phillips Mar 1998

How To Reduce Drought Risk, Cody Knutson, Mike Hayes, Tom Phillips

National Drought Mitigation Center: Faculty Publications

This guide describes a practical step-by-step process for identifying actions that can be taken to reduce potential drought-related impacts before a drought occurs. Step 1 begins with making sure that the right people are brought together and supplied with adequate data to make informed and equitable decisions during the process. Steps 2 and 3 narrow the focus of the study by identifying high priority drought-related impacts that are relevant to the user’s location or activity. Step 4 demonstrates that in order to reduce the potential for the identified impacts to occur in the future, it is necessary to understand the …


Hydrology Of Two Interdunal Valleys In The Nebraska Sand Hills, Steve Drda Feb 1998

Hydrology Of Two Interdunal Valleys In The Nebraska Sand Hills, Steve Drda

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Two neighboring interdunal valleys are compared within a study area of about 15 square miles in the Nebraska Sand Hills. One is a subirrigated wet meadow drained by a manmade ditch. The other is topographically lower, but dry at the surface. The goal of this study is to identify the factors responsible for the hydrologic regime present in each valley, and to discern the reasons for the differences between the two valleys. Water levels in 39 piezometers positioned at different locations across both valleys, and at different depths were monitored for two-and-a-half years to determine groundwater flow paths, gradients, and …


Inventory Of Sub-Catchments Within The Wilson Inlet Catchment, B Radys Jan 1998

Inventory Of Sub-Catchments Within The Wilson Inlet Catchment, B Radys

Resource management technical reports

The release of the "Salinity Action Plan for Western Australia' in December 996 highlighted the need for catchment scale planning and coordinated actions to reverse salinity trends.

A separate report has been produced for each major catchment area. Each report contains and inventory of all sub-catchments. with information on area, degradation risks and group activities with each catchment.


Chapter 2 Climate, Donald A. Wilhite, Kenneth G. Hubbard Jan 1998

Chapter 2 Climate, Donald A. Wilhite, Kenneth G. Hubbard

National Drought Mitigation Center: Faculty Publications

The broad climatic patterns of the Sand Hills region are also characteristic of the central Great Plains environment. The spatial and temporal patterns of these climatic variables have a significant effect on the natural resources of the region.


Inventory Of Sub-Catchments Within The Oyster Harbour Catchment, B Radys Jan 1998

Inventory Of Sub-Catchments Within The Oyster Harbour Catchment, B Radys

Resource management technical reports

The release of the "Salinity Action Plan for Western Australia' in December 996 highlighted the need for catchment scale planning and coordinated actions to reverse salinity trends.

A separate report has been produced for each major catchment area. Each report contains and inventory of all sub-catchments, with information on area, degradation risks and group activities with each catchment.


Inventory Of Sub-Catchments Within The Albany Eastern Hinterland, B Radys Jan 1998

Inventory Of Sub-Catchments Within The Albany Eastern Hinterland, B Radys

Resource management technical reports

The release of the "Salinity Action Plan for Western Australia' in December 996 highlighted the need for catchment scale planning and coordinated actions to reverse salinity trends.

A separate report has been produced for each major catchment area. Each report contains and inventory of all sub-catchments, with information on area, degradation risks and group activities with each catchment.


Heat And Salt Changes On The Continental Shelf West Of The Antarctic Peninsula Between January 1993 And January 1994, John M. Klinck Jan 1998

Heat And Salt Changes On The Continental Shelf West Of The Antarctic Peninsula Between January 1993 And January 1994, John M. Klinck

CCPO Publications

Hydrographic measurements from four cruises between January 1993 and January 1994 over the continental shelf west of the Antarctic Peninsula allow analysis of seasonal changes in heat and salt content of this region. Changes above the permanent pycnocline (about 150 m) follow a seasonal pattern of cooling and increasing in salt from summer to winter and warming and freshening from winter to summer. These near-surface changes expressed as net heating or salting rate, were above 80 W m(-2) and 4 mg salt m(-2) s(-1). The year to year difference was small compared to the seasonal changes. There was no seasonal …


Review Of The United States Environmental Protection Agency Superfund Technical Assistance Grant Program, Robert Leslie Annear, Scott A. Wells, Shuguang Li, Marvin Beeson, Michael L. Cummings, Richard Pratt Jun 1997

Review Of The United States Environmental Protection Agency Superfund Technical Assistance Grant Program, Robert Leslie Annear, Scott A. Wells, Shuguang Li, Marvin Beeson, Michael L. Cummings, Richard Pratt

Civil and Environmental Engineering Faculty Publications and Presentations

The EPA Technical Assistance Grant Program has been around for several years, but there are not many examples of its use in the Pacific Northwest from which citizens can learn from when considering applying for a Technical Assistance Grant. The EPA program is designed to provide citizens with technical assistance in understanding the issues related to a Superfund site (or proposed Superfund site) in their community. This report provides an overview of the Technical Assistance Grant Program with information on applying for the grant, selecting a Technical Advisor and managing the grant. Additionally two case studies are reviewed in order …


Estimation Of Groundwater Velocities From Yucca Flat To The Amargosa Desert Using Geochemistry And Environmental Isotopes, Ronald L. Hershey, Steve Y. Acheampong Jun 1997

Estimation Of Groundwater Velocities From Yucca Flat To The Amargosa Desert Using Geochemistry And Environmental Isotopes, Ronald L. Hershey, Steve Y. Acheampong

Publications (WR)

Geochemical modeling techniques were applied to groundwater flowpaths from Yucca Flat on the Nevada Test Site (NTS) to the Amargosa Desert, south of the NTS to estimate groundwater flow velocities for independent comparison to velocities calculated by other methods. The groundwater flowpaths examined considered flow in the carbonate aquifer beneath Yucca and Frenchman flats mixing with flow from carbonate aquifers east and southeast of the NTS and discharging at wells south of the NTS border. The approach used the computer codes WATEQ4F and NETPATH to calculate chemical speciation, determine the saturation state of mineral phases, and simulate mixing and the …


Bulletin 4333 - Furrow Sowing On Water Repellent Soils, Paul Blackwell, Grant Morrow Mar 1997

Bulletin 4333 - Furrow Sowing On Water Repellent Soils, Paul Blackwell, Grant Morrow

Bulletins 4000 -

This Bulletin discusses the benefits that furrow sowing brings to crop growth and production on water repellent sand, based on research and farm observations in Western Australian. By understanding the benefits and risks of several key processes, producers can better evaluate the potential role of furrow sowing in combating water repellency. This is true whether one is using direct drilling, no-till (narrow points or discs) or zero till (single, double or triple disc openers) methods.


The Columbia Slough, Scott A. Wells Mar 1997

The Columbia Slough, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

This report was written in an attempt to provide the public and Bureau of Environmental Services Staff with a summary of work accomplished on the Columbia Slough system by Portland State University and other consultants working on the Slough over the last 6 years. An attempt was made to create an easy-to-read report with important overviews of the "big picture", glossary of definitions, index, and further details to assist in technology transfer.


Fresh-Water Aquifer In The Knox Group (Cambrian–Ordovician) Of Central Kentucky, James A. Kipp Jan 1997

Fresh-Water Aquifer In The Knox Group (Cambrian–Ordovician) Of Central Kentucky, James A. Kipp

Report of Investigations--KGS

Fresh water can be found in Cambrian and Ordovician carbonate rocks of the Knox Group in central Kentucky. The top of the aquifer is as much as 300 ft above mean sea level (m.s.l.) on the crest of the Cincinnati Arch, but descends off the flanks of the arch. Water is normally found in the upper 100 to 250 ft of the Knox, primarily in secondary porosity apparently associated with the unconformity at the top of the unit. Knox wells commonly exceed 750 ft in total depth, but because the aquifer is artesian, water rises to an elevation of about …


Hydrogeological And Hydrochemical Connection Between The Decatur City Spring And Crystal Lake, Benton County, Arkansas, Demetra O. Salisbury, Ralph K. Davis Jan 1997

Hydrogeological And Hydrochemical Connection Between The Decatur City Spring And Crystal Lake, Benton County, Arkansas, Demetra O. Salisbury, Ralph K. Davis

Journal of the Arkansas Academy of Science

Arkansas is ranked nationally in the production of broilers, laying hens, turkey, swine and beef cattle. These animals produce large volumes of waste, which are spread on pasture land as a method of disposal, as well as a source of fertilizer, resulting in nonpoint source contamination of surface water and ground water. One area of concern includes the Decatur City Spring, which provides municipal water for the city of Decatur. A total of eight sites in the surrounding area were monitored routinely for water quality parameters, including pH, specific conductance, and nitrate-nitrogen. Water temperature and spring and lake stage were …


Ground Water, Robert F. Diffendal Jr. Jan 1997

Ground Water, Robert F. Diffendal Jr.

Department of Earth and Atmospheric Sciences: Faculty Publications

A geologic overview of the groundwater supply underlying Cheyenne County, Nebraska (1997).


Western Australian Salinity Action Plan, Agriculture Western Australia, Department Of Conservation And Land Management, Department Of Environmental Protection, Water And Rivers Commission Nov 1996

Western Australian Salinity Action Plan, Agriculture Western Australia, Department Of Conservation And Land Management, Department Of Environmental Protection, Water And Rivers Commission

Natural resources published reports

Salinity is one of the State's most critical environmental problems, threatening major economic and social consequences. It is preventable and, in the long term, reversible. Complete elimination is not realistic, but we can dramatically reduce its impact.

Salinity is caused by replacing deep-rooted native plants with shallow-rooted crops and pastures. More rainfall passed below the root zone and accumulates as groundwater so that watertables rise. The groundwater mobilises natural salts in the soil as it rises and carries them towards the surface, eventually degrading land and streams.


Influence Of Rice Production On The Quality Of Water In Tailwater Collection Reservoirs, R. A. Dewell, T. L. Lavy Jun 1996

Influence Of Rice Production On The Quality Of Water In Tailwater Collection Reservoirs, R. A. Dewell, T. L. Lavy

Arkansas Water Resources Center Technical Reports

Since maintaining high water quality standards in the state remains a high priority, monitoring for pesticides in water sources must continue. Determining the type, concentration, and characteristics of any pesticides present in water supplies are essential to the overall assessment of water quality. Five independent locations, implementing contained water management systems and recyclable water, were monitored in 1995 and 1996. Irrigation, runoff, and pond water samples were collected every 10 to 14 days between permanent flood establishment and draining. Water samples were transported to the laboratory and extracted for 16 pesticides using solid phase extraction (SPE) techniques. Quantification and confirmation …


Effects Of Zebra, Mussel, Dreissena Polymorpha Infestation On Lake Dardanelle Water Quality, Charles J. Gagen, Joseph N. Stoeckel Jun 1996

Effects Of Zebra, Mussel, Dreissena Polymorpha Infestation On Lake Dardanelle Water Quality, Charles J. Gagen, Joseph N. Stoeckel

Arkansas Water Resources Center Technical Reports

Zebra mussels recently invaded southern waterways including the Arkansas River. Large-scale filtration of suspended particulate matter by dense populations could alter reservoir ecosystem function. Furthermore, they attach to hard surfaces, thereby threatening normal operations of artificial structures. We designed this study to provide baseline data prior to establishment of high population levels of zebra mussels in Lake Dardanelle. The characterization of spatial and temporal variability in water quality, zooplankton, phytoplankton, and macrophytes will allow testing of several hypotheses. We sampled zebra mussel veliger and settling juvenile densities and zooplankton densities at four fixed sites and the key water quality variables …


Bioaccumulation Of Methyl Mercury Through A Food Chain, J. T. Knight Jun 1996

Bioaccumulation Of Methyl Mercury Through A Food Chain, J. T. Knight

Arkansas Water Resources Center Technical Reports

The bioaccumulation of mercury through the food chain has received much attention in Arkansas during the last three years. The discovery of mercury contamination and subsequent fish consumption advisories in southwest Arkansas have increased public awareness of the potential for bioaccumulation of different toxic compounds. It is postulated that the mercury problem in Arkansas is a result of methylation and resulting bioaccumulation of mercury as methyl mercury. This study was designed to derive a Bioaccumulation Factor (BAF) for mercury in a simple food chain under controlled conditions. A BAF is calculated by dividing the concentration found in the organism by …


Trace Element Analysis Of Selected Springs In The Virgin River Basin, Mary A. Yelken May 1996

Trace Element Analysis Of Selected Springs In The Virgin River Basin, Mary A. Yelken

UNLV Theses, Dissertations, Professional Papers, and Capstones

Spring water from 23 springs in and near the Virgin River Basin (southwestern Utah, northwestern Arizona, and southeastern Nevada) was collected and analyzed for chemical concentrations. Trace elements and major ion chemistry was used to determine the potential for utilizing water chemistry to provide information on spring water source and flow pathways. Principal Component Analysis (PCA), rare earth element (REE) normalization patterns, and mineral equilibrium modeling (PHREEQE) techniques were used to analyze the data set. Four major spring water groups were displayed by the PCA, based on similarities in water chemistry. The analyses suggest that spring water chemistry is a …


Survival Of Fecal Contamination Indicator Organisms In Soil, K. A. Teague, D. C. Wolf, P. F. Vendrell Sep 1995

Survival Of Fecal Contamination Indicator Organisms In Soil, K. A. Teague, D. C. Wolf, P. F. Vendrell

Arkansas Water Resources Center Technical Reports

Soils amended with human or animal waste may result in pathogen contamination of ground and surface water. Because temperature has been shown to affect pathogen survival, two laboratory studies were conducted to evaluate the impact of extremes in temperature on bacterial and viral pathogen indicator die-off in soil. A Captina silt loam was amended with broiler litter (0.1 g/g dry soil), septic tank effluent, or Escherichia coli (ATCC 13706) culture (both at 0.04 and 0.1 mL/g dry soil in the two respective studies), incubated at 5 and 35°C, and analyzed over time to determine the number of fecal coliform, E. …


Spatial Distribution Of The Surface Geology And 1992 Land Use Of The Buffalo River Watershed, Kimberly R. Hofer, H. Don Scott, James M. Mckimmey Jul 1995

Spatial Distribution Of The Surface Geology And 1992 Land Use Of The Buffalo River Watershed, Kimberly R. Hofer, H. Don Scott, James M. Mckimmey

Arkansas Water Resources Center Technical Reports

The Buffalo River was established by Congress in 1972 as the first National River in the United States and is one of the few remaining free-flowing streams in Arkansas . The Buffalo River flows through the three major physiographic provinces of northern Arkansas, originating in the higher elevations of the Boston Mountains, and flowing generally northeastward to cut through the Springfield and Salem Plateaus. It drops from approximately 2000 feet in the headwaters to around 500 feet above sea level at its confluence with the White River in Marion County. The Buffalo River is considered to be one of Arkansas' …


Spatial And Temporal Analysis Of The Morphological And Land Use Characteristics Of The Buffalo River Watershed, H. Don Scott, Kimberly R. Hofer Jul 1995

Spatial And Temporal Analysis Of The Morphological And Land Use Characteristics Of The Buffalo River Watershed, H. Don Scott, Kimberly R. Hofer

Arkansas Water Resources Center Technical Reports

The Buffalo River was established by Congress iQ. 1972 as the first National River in the United States. The Buffalo River, which originates in the higher elevations of the Boston Mountains in Newton County, is one of the few remaining free-flowing streams in Arkansas. It is considered to be one of Arkansas' greatest natural treasures, and thus, there is strong interest in protecting it from anthropogenic influences. An initial characterization of the soil taxonomic units, watershed boundaries, topography and physiographic units in the Buffalo River Watershed was presented by Scott and Smith (1994). The spatial distribution of the geologic units …


The Effect Of Arctic River Hydrological Cycles On Arctic Ocean Circulation, Peter Becker Jul 1995

The Effect Of Arctic River Hydrological Cycles On Arctic Ocean Circulation, Peter Becker

OES Theses and Dissertations

Understanding Arctic Ocean circulation may be critical to fully understanding the global oceanic salt and heat cycles and their response to climate variability. This thesis examines how one important aspect of Arctic Ocean circulation, the effect of freshwater inflow, may contribute to the variability of these cycles. The multiple roles that freshwater runoff performs in the Arctic Ocean include: (1) the formation of shelf and basin scale density currents; (2) maintenance of the strong density stratification; (3) control of the thickness and strength of the ice pack; and (4) control of deep convection. Sources and sinks of freshwater in the …


Effects Of Zebra Mussel, Dreissena Polymorpha, Infestation On Lake Dardanelle Water Quality, Charles J. Gagen, Joseph N. Stoeckel Jun 1995

Effects Of Zebra Mussel, Dreissena Polymorpha, Infestation On Lake Dardanelle Water Quality, Charles J. Gagen, Joseph N. Stoeckel

Arkansas Water Resources Center Technical Reports

Zebra mussels recently invaded southern waterways including the Arkansas River. Exponential population growth and high filtration capacity of dense populations could alter reservoir ecosystem function. Furthermore, they attach to hard surfaces; thus, threatening normal operations of many artificial structures. We designed this study to provide baseline data prior to high population levels of zebra mussels in Lake Dardanelle. The characterization of spatial and temporal variability in water quality, zooplankton, phytoplankton, and macrophytes will allow testing of several hypotheses. We sampled zebra mussel density and zooplankton at four fixed sites and the other key variables at three of these sites biweekly …


Assessment Of Effectiveness Of Buffer Zones In Removing Impurities In Runoff From Areas Treated With Poultry Litter. Part Ii: Source Areas To Buffer Areas Ratio Effects, P. Srivastava, D. R. Edards, T. C. Daniel Jun 1995

Assessment Of Effectiveness Of Buffer Zones In Removing Impurities In Runoff From Areas Treated With Poultry Litter. Part Ii: Source Areas To Buffer Areas Ratio Effects, P. Srivastava, D. R. Edards, T. C. Daniel

Arkansas Water Resources Center Technical Reports

Vegetative filter strips (VFS) are known to reduce runoff losses of nutrients. solids. and other materials from land areas treated with fertilizers . Although VFS effectiveness is known to depend partially on the relative lengths of filter and pollutant source areas. there is little experimental evidence available to quantify this dependence. This is particularly the case when VFS are implemented down-slope of pasture areas treated with animal manures such as poultry litter. This study assessed the influences of pollutant source area (treated with poultry litter) and VFS lengths on VFS removal of total Kjeldahl nitrogen (TKN). ammonia nitrogen (NH3 -N …


An Understanding Of Factors Controlling Isotopic Ratios Of Wine As A Potential Surrogate Of Past Precipitation, Eric Alan Caldwell May 1995

An Understanding Of Factors Controlling Isotopic Ratios Of Wine As A Potential Surrogate Of Past Precipitation, Eric Alan Caldwell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Precipitation, vapor water, ground water, soil water, grape berry and grape leaf water, grape must, and vintage wines were collected from northern California for stable isotopic analysis. An understanding of factors controlling isotopic ratios of wine allows evaluation of wine as a surrogate of past precipitation. Stable isotopic compositions of grape berry waters collected at Charles Krug Winery in Napa Valley. CA range from -31 to -17 per mil in 8D and +7.2 to +15.3 per mil in 8180, and plot along a transpiration line of slope 2. 7. Grape leaf waters range from -25 to +5 per mil in …


Geology Of The Ogallala/High Plains Regional Aquifer System In Nebraska, Robert F. Diffendal Jr. Apr 1995

Geology Of The Ogallala/High Plains Regional Aquifer System In Nebraska, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

This guide is mostly figures with a reference section containing some of the pertinent literature on the Cenozoic geology we will see over the next four days. Copies of some of the cited works will be assembled in a packet and handed out on the morning of April 29th. We will make all 17 stops. if the weather is reasonably good and the roads are passable. On the first day, April 29, we will try to get to stops 1-5, the more distal parts of the Ogallala and younger deposits in Nebraska. On April 30, we will try to visit …