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Articles 241 - 270 of 295

Full-Text Articles in Environmental Health and Protection

Landscape Plants, Forest Trees, And Crops Most Resistant To Mammal Damage: An Overview, Rex E. Marsh Apr 1991

Landscape Plants, Forest Trees, And Crops Most Resistant To Mammal Damage: An Overview, Rex E. Marsh

Great Plains Wildlife Damage Control Workshop Proceedings

To capitalize on mammal-resistant plants, several approaches may be taken. The most common is to select crops not highly prone to mammal damage (i.e., resistant crops). If a generally susceptible crop is to be grown, the more resistant varieties or cultivars of that crop can be selected, if known. An approach that has not received the attention it warrants is the selection of parent stock with resistant characteristics and the selective breeding of useful species to develop strains, hybrids, or cultivars with improved mammal resistance. For several reasons, this latter approach shows the most promise for forest tree species. It …


Littoral And Limnetic Zooplankton Communities In Lake Mead, Nevada-Arizona, Usa, Patrick J. Sollberger, Larry J. Paulson Jan 1991

Littoral And Limnetic Zooplankton Communities In Lake Mead, Nevada-Arizona, Usa, Patrick J. Sollberger, Larry J. Paulson

Publications (WR)

Zooplankton were collected from adjacent littoral and limnetic sites in Lake Mead, Nevada-Arizona, USA. Limnetic species dominated both littoral and limnetic zooplankton communities; littoral species rarely exceeded 2% of monthly total zooplankton densities. Low species richness of littoral taxa and high similarity in species composition between littoral and limnetic habitats appeared to result from uniform horizontal physical and chemical environments, due to horizontal mixing, and from the absence aquatic macrophytes. Significant differences in spatial distribution occurred in phytoplankton biomass, total zooplankton density, and fish "abundances; highest concentrations of these factors occurred nearest an inflow high in nutrients and progressively declined …


Enhancement And Monitoring Of The Procambarus Clarkii Population In Lake Mead, Mikell Beth Hager May 1990

Enhancement And Monitoring Of The Procambarus Clarkii Population In Lake Mead, Mikell Beth Hager

Publications (WR)

Procambarus clarkii are found in extremely low numbers throughout Lake Mead, AZ-NV. The crayfish are an important dietary component for game fish. Enhancement of the crayfish population would broaden the fishery forage base. Crayfish were stocked and monitored in a study cove on Saddle Island to determine if the Procambarus clarkii population could be enhanced. A trapping survey of the area after the following reproductive season yielded low numbers of crayfish. A comparison of pre-stocking and post-stocking catch per trap day (CPTD) values revealed no significant increase in the population. Procambarus clarkii growth is limited by environmental factors in Lake …


The Development Of A Policy For The Management Of Dingo Populations In South Australia, R. J. Downward, J. E. Bromell Mar 1990

The Development Of A Policy For The Management Of Dingo Populations In South Australia, R. J. Downward, J. E. Bromell

Vertebrate Pest Conference Proceedings: 14th (1990)

Competing concerns between conservation and sheep-growing interests in South Australia over problems associated with the naturalized dog,Canis familiaris dingo, prompted the development of a policy for the management of this subspecies. The background to the development of this policy is outlined. The policy provides for a compromise between the need to protect the livestock industry while ensuring the continued survival of the dingo as a wildlife species.


A Resource Inventory And Impact Analysis Of Great Bog And The Horse Point Delta/Esker System, Problems In Environmental Science Course (Biology 493), Colby College, Biologists Organized For Ecosystem Assessment, Colby College Jan 1990

A Resource Inventory And Impact Analysis Of Great Bog And The Horse Point Delta/Esker System, Problems In Environmental Science Course (Biology 493), Colby College, Biologists Organized For Ecosystem Assessment, Colby College

Colby College Watershed Study: Other Area Studies

In May of 1990, Tilcon-Maine, Inc. submitted an application to mine gravel on the east side of Horse Point Road on Horse Point in the Town of Belgrade. The project site covers 46 acres and the proposed excavation covers 16 acres. An estimated 740,000 cubic yards of material will be removed over a period of six or seven years (Pfister, pers. comm.). According to Tilcon (Timson et al., 1990) the maximum depth of the pit will be 78 feet and the bottom of the pit will be a minimum of 6 feet above the water table. At the present time …


Fisheries Research Report No. 84 - The Marine Open Shelf Environment: Review Of Human Influences, D. A. Hancock Jan 1990

Fisheries Research Report No. 84 - The Marine Open Shelf Environment: Review Of Human Influences, D. A. Hancock

Fisheries Research Reports

For the purpose of this review, the marine environment has been classified into three physical zones - the littoral zone, the open-shelf environment and the coral reef. Since the boundaries are arbitrary, there will inevitably be some overlap, but for this review the subject matter will be related to the area between low water of ordinary spring tides and the edge of the continental shelf; i.e., to a depth varying to 200 metres.

Human influences may have a dual role in affecting the marine environment, firstly in a causative manner and secondly in providing a remedy, in which case the …


Fisheries Management Paper No.23 - Management Of The South-West Inshore Trawl Fishery., N. Moore Feb 1989

Fisheries Management Paper No.23 - Management Of The South-West Inshore Trawl Fishery., N. Moore

Fisheries Management Papers

This report outlines the management plan for the south west inshore trawl fishery which already operates in coastal waters less than 200 metres deep between Guilderton and Cape Leeuwin.

This management plan takes into account these important concerns and has specifically set aside a strip of coastal area from Cape Bouvard to Cape Leeuwin for recreational usage and for protection of the benthic community, and closed the management zone north of Burns Beach to trawling.


Agenda For Action - Casco Bay, Department Of Environmental Protection Jan 1989

Agenda For Action - Casco Bay, Department Of Environmental Protection

Maine Collection

Agenda For Action - Casco Bay

Department of Environmental Protection, Augusta, Maine (January, 1989)

Contents: Introduction / The Problems : Bacteria, Toxics, Nutrients / The Solutions / Recommendations / References


Riparian Plant Water Relations Along The North Fork Of The Kings River, California, J. L. Nachlinger, S. D. Smith, R. J. Risser Jan 1989

Riparian Plant Water Relations Along The North Fork Of The Kings River, California, J. L. Nachlinger, S. D. Smith, R. J. Risser

Life Sciences Faculty Research

Plant water relations of five obligate ripar-ian species were studied along California's North Fork Kings River. Diurnal stomatal conductance, transpi-ration, and xylem pressure potentials were measured throughout the 1986 growing season and in mid-season in 1987. Patterns were similar for all species although absolute values varied considerably. Maximum stomatal conductance occurred early in the day and season during favorable environmental conditions and decreased as air temperature and the vapor pressure difference between the leaf and air increased. Maximum transpiration rates occurred in mid-morning and mid-summer resulting in estimated daily water losses per unit sunlit leaf area of 163-328 mol H2O …


Maine Nonpoint Source Pollution Assessment Report, Bureau Of Water Quality Control Jan 1989

Maine Nonpoint Source Pollution Assessment Report, Bureau Of Water Quality Control

Maine Collection

Maine Nonpoint Source Pollution Assessment Report

Prepared by the Maine Department of Environmental Protection, Bureau of Water Quality Control, Augusta, Maine 1989.

Contents: Executive Summary / Introduction / Methodology / Statewide Water Quality Summary / State And Local Agency Programs for Control of Nonpoint Source Pollution / Process for Identification of Best Management Practices and Associated Standards / List of References / List of Figures / List of Tables



Characterization Of The Aquatic Environment In Lake Mead Near The Proposed Spring Canyon Pumped-Storage Project, And Assessment Of Potential Aquatic Impacts, Charles R. Liston, Stephen J. Grabowski, Bureau Of Reclamation Jun 1988

Characterization Of The Aquatic Environment In Lake Mead Near The Proposed Spring Canyon Pumped-Storage Project, And Assessment Of Potential Aquatic Impacts, Charles R. Liston, Stephen J. Grabowski, Bureau Of Reclamation

Publications (WR)

A pumped storage system consists of an upper reservoir and lower reservoir separated by an elevation difference. During low demand energy periods such as nights and weekends water is pumped from the lower to the upper reservoir using available energy from conventional steam electric power plants. During high energy demand periods, such as mornings and afternoons of weekdays, upper reservoir water is allowed to drop back down through the same system of water conduits and turbines, generating electricity to conveniently meet abrupt electrical energy requirements. The same water turbines thus act both as pumps and as conventional hydroelectric turbines. Because …


A Field Perspective On Groundwater Contamination, John A. Cherry May 1988

A Field Perspective On Groundwater Contamination, John A. Cherry

Maine Collection

A Field Perspective on Groundwater Contamination

Geological Society of Maine Distinguished Lecturer John Cherry, University of Waterloo, Ontario, sponsored by the Department of Geosciences, University of Southern Maine, 19th May 1988.

Contents: Lecture 1 : Contaminant Migration Processes Illustrated by Field Experiments / Lecture 2 : Behavior of Dense Non-Aqueous Phase Liquids, Illustrated by Lab Experiments and Conceptual Examples / Lecture 3 : Field Case Histories on Groundwater Contamination / Lecture 4 : Hydrogeological Concepts and Criteria for Waste Disposal / Waterloo Center for Groundwater Research Publications List


Environmental Assessment Of Las Vegas Wash And Lake Mead Artificial Wetlands Demonstration Project, John R. Baker, R. M. Gersberg, U.S. Environmental Protection Agency Feb 1988

Environmental Assessment Of Las Vegas Wash And Lake Mead Artificial Wetlands Demonstration Project, John R. Baker, R. M. Gersberg, U.S. Environmental Protection Agency

Publications (WR)

The effective use of artificial wetlands for treatment of municipal wastewater is well documented; however, design and economic data for artificial wetlands development are limited (Gersberg et al., 1984a). This is due partly to regional differences in climate, soils, and vegetation and partly to the desired waste treatment. As a result, specific treatment levels and cost benefits relative to the use of an artificial wetlands for a particular site cannot be evaluated adequately without a pilot demonstration project. Las Vegas Wash receives sewage effluent from the Las Vegas metropolitan area and has been designated as a wetlands community park. Las …


Limnological Monitoring Data For Lake Mead During 1987: Technical Report No. 20, Larry J. Paulson Jan 1988

Limnological Monitoring Data For Lake Mead During 1987: Technical Report No. 20, Larry J. Paulson

Publications (WR)

Limnological monitoring was conducted in Las Vegas Bay and Boulder Basin from April to December of 1987. The purpose of the monitoring was to (i) document possible changes in water quality resulting from decreased phosphorus loading in Las Vegas Wash, and (ii) establish a data base for evaluating the adequacy of water quality standards.


Changes In The Morphometry Of Las Vegas Wash And The Impact On Water Quality, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation Jan 1988

Changes In The Morphometry Of Las Vegas Wash And The Impact On Water Quality, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation

Publications (WR)

Las Vegas Wash, a natural wash east of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from two sewage treatment plants to Lake Mead. Over 80 percent of the normal discharge of approximately 3.4 m3/s (120 ft3/s) consists of effluent from the City of Las Vegas and Clark County sewage treatment plants. Beginning in the 1950s, a large wetland area developed along the wash that supported waterfowl populations and contributed to some water quality transformations. Heavy rains and subsequent flooding in the area in 1983 and 1984 resulted in erosion and channelization that greatly …


Las Vegas Wash And Lake Mead Proposed Water Quality Standards: Revisions And Rationale, State Of Nevada: Division Of Environmental Protection May 1987

Las Vegas Wash And Lake Mead Proposed Water Quality Standards: Revisions And Rationale, State Of Nevada: Division Of Environmental Protection

Publications (WR)

Rationale of review and for proposed changes to the Nevada Pollution Control Regulations (NAC 445.1354, 445.1355, 445.1356, 455.1367, 445.1352, 445.1353, 445.1350, 445.1351) before the State Environmental Commission on June 23 and 24, 1987.


Maine Acid Rain Study : Reports, Maine Department Of Environmental Protection Feb 1987

Maine Acid Rain Study : Reports, Maine Department Of Environmental Protection

Maine Collection

Maine Acid Rain Study : Reports

Maine Department of Environmental Protection, Augusta, Maine (February, 1987).

Contents: Acid Rain Precursor Inventory and Evaluation / Modeled Sulfur Deposition in Maine / High Elevation Lake Monitoring in Maine


A Proposal To Fertilize The Overton Arm And Gregg Basin Areas Of Lake Mead, Larry J. Paulson Nov 1984

A Proposal To Fertilize The Overton Arm And Gregg Basin Areas Of Lake Mead, Larry J. Paulson

Publications (WR)

Several limnological studies have been conducted in Lake Mead during the past decade. The recent studies clearly show that most of Lake Mead is deficient in nutrients, especially phosphorus, and very low in productivity. The reservoir-wide average total phosphorus concentration for 1981 - 1982 was only 9 mg/m3. This is below levels found In most oligotrophic lakes and reservoirs. Algal biomass, as measured by chlorophyll-a, averaged only 1.5 mg/m3. That also places Lake Mead in the oligotrophic range. Transparency, as measured by a Secchi disc, averaged 9-5 m in Lake Mead during 1981-1982. That far exceeds …


Seasonal And Spatial Heterogeneity In The Limnetic Zooplankton Community Of Lake Mead, Gene Robert Wilde May 1984

Seasonal And Spatial Heterogeneity In The Limnetic Zooplankton Community Of Lake Mead, Gene Robert Wilde

Publications (WR)

Zooplankton samples collected from throughout Lake Mead, in 1981-1982, demonstrate the presence of a statistically significant seasonal and spatial heterogeneity in zooplankton densities. Seasonally, the major zooplankton groups were most abundant in the spring and fall, coincident with maxima in chlorophyll-a concentrations. Successions among the various rotifers, cladocerans and copepods present in the reservoir were influenced by food availability, diapause, predation by planktivorous fish and, possibly, water temperatures. Spatial heterogeneity in zooplankton densities was unrelated to water temperature, pH, conductivity and dissolved oxygen concentrations, but was related to the abundance of phytoplankton (chlorophyll-a concentrations) and fish. Statistical analyses indicate that …


The Role Of Nannoplankton In The Phytoplankton Dynamics Of Four Colorado River Reservoirs (Lakes Powell, Mead, Mohave, And Havasu), Jeffrey John Janik May 1984

The Role Of Nannoplankton In The Phytoplankton Dynamics Of Four Colorado River Reservoirs (Lakes Powell, Mead, Mohave, And Havasu), Jeffrey John Janik

Publications (WR)

Phytoplankton species composition and community size structure were studied in four warm-monomictic Colorado River reservoirs; lakes Powell, Mead, Mohave, and Havasu from March 1981 to February 1982. Sampling was done at approximately monthly intervals from several stations in each reservoir. The Utermohl technique was used to enumerate phytoplankton. The phytoplankton assemblage was divided into the following six size classes using microscopic techniques; netplankton (>64 um), and nannoplankton (>5, 5-11, 12-21, 22-44, and 45-64 um).

Total phytoplankton biomass and community size structure were different among these four reservoirs with considerable spatial and temporal variation present. Average reservoir-wide areal weighted …


Las Vegas Wash Multispectral Scanner Survey, T. H. Mace, M. V. Olsen, Environmental Protection Agency Feb 1984

Las Vegas Wash Multispectral Scanner Survey, T. H. Mace, M. V. Olsen, Environmental Protection Agency

Publications (WR)

At the request of the U.S. Bureau of Reclamation, Boulder City, Nevada, the U.S. Environmental Protection Agency's Environmental Monitoring Systems Laboratory at Las Vegas collected multispectral scanner imagery of Las Vegas Wash on October 1, 1982. A combined maximum likelihood classification and editing procedure was used to classify the multispectral scanner imagery into 12 categories of land cover. The classification identified four categories of marsh vegetation, one category of riparian, two categories of mixed scrub, and two desert categories. Turbid water and cultivated land formed an "other" category. Area tabulations were formed by georeferencing the classification to the Universal Transverse …


Algal Growth And The Phosphorus Cycle, Arthur J. Mccomb, K. S. Hamel, A. L. Huber, D. K. Kidby, R. J. Lukatelich Jan 1984

Algal Growth And The Phosphorus Cycle, Arthur J. Mccomb, K. S. Hamel, A. L. Huber, D. K. Kidby, R. J. Lukatelich

Journal of the Department of Agriculture, Western Australia, Series 4

Larger algae and microscopic phytoplankton foul the waters of the Peel-Harvey estuarine system, upsetting the fishery and polluting the beaches.

These aquatic plants grow in response to phosphorus runoff from drainage, trapping phosphorus in the estuary and using it in their growth. When they die this phosphorus remains in the system to be recycled for further plant growth.

Algal pollution in the estuary can be lessened by reducing the amount of phosphorus entering the system, increasing phosphorus losses to the ocean, or in some way blocking the trapping and recycling processes.


Tackling The Problem Off The Farm, C M. Croft Jan 1984

Tackling The Problem Off The Farm, C M. Croft

Journal of the Department of Agriculture, Western Australia, Series 4

Methods of redusing phosphorus losses from the catchment soils of the Peel-Harvey esturine system have been discussed in other articles in this Journal.

This article briefly discusses a range of 'off the farm' techniques to improve phosphorus flushing from Peel Inlet or Harvey Estuary to the sea and to treat the phosphorus and the algae. These techniques were among more than 100 management options evaluated by the Peel-Harvey Study Group.


Las Vegas Wash Advanced Water Quality Study: Final Report, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation Jan 1984

Las Vegas Wash Advanced Water Quality Study: Final Report, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation

Publications (WR)

The purpose of the Las Vegas Wash Advanced Water Quality Study is to determine the existence, extent, and mechanisms of nutrient and toxin stripping in Las Vegas Wash under present conditions and under future conditions, both with and without construction of the proposed salinity control unit as described by the Bureau of Reclamation (USBR, 1982b). This study was performed for the Lower Colorado Region Division of Planning by personnel of the Environmental Sciences Section of the Division of Research and Laboratory Services, E&R Center, Denver, Colorado. Work on the study began in February 1983. The general approach adopted for this …


Water Quality Trends In The Las Vegas Wash Wetlands, F. A. Morris, L. J. Paulson Jan 1983

Water Quality Trends In The Las Vegas Wash Wetlands, F. A. Morris, L. J. Paulson

Publications (WR)

The Las Vegas Wash is a wetlands ecosystem that acts to buffer the effects of wastewater discharges on the receiving waters of Lake Mead. The wash is the terminus for the 4,144 km2 Las Vegas Valley drainage basin, emptying into Las Vegas Bay of Lake Mead (Colorado River). It is in the northern Mojave desert, which receives an average of only 10 cm of rainfall annually. The Las Vegas Wash is technically an artificial wetland supported almost entirely by the perennial flows from sewage treatment plants. These flows contribute an average of 3-7 t of nutrients (nitrogen and phosphorus) and …


The Influence Of Lake Powell On The Suspended Sediment-Phosphorus Dynamics Of The Colorado River Inflow To Lake Mead, T. D. Evans, Larry J. Paulson Jan 1983

The Influence Of Lake Powell On The Suspended Sediment-Phosphorus Dynamics Of The Colorado River Inflow To Lake Mead, T. D. Evans, Larry J. Paulson

Publications (WR)

The Colorado River has been successively modified by the construction of several reservoirs, beginning in 1935 with the formation of Lake Mead by Hoover Dam. These reservoirs are located in a chain, and each one has an influence on the nutrient dynamics and productivity of the river and downstream reservoir. Lake Mead derives 98% of its annual inflow from the Colorado River. Historically, the Colorado River inflow was unregulated into Lake Mead. Regulation occurred in 1963, when Lake Powell was impounded by the construction of Glen Canyon Dam, approximately 450 km upstream. The formation of Lake Powell drastically altered the …


The Voluntary Water Quality Monitoring Program : 1982 Project Report, Barbara Welch, Judy Potvin, Mary Ellen Dennis Jan 1982

The Voluntary Water Quality Monitoring Program : 1982 Project Report, Barbara Welch, Judy Potvin, Mary Ellen Dennis

Maine Collection

The Voluntary Water Quality Monitoring Program : 1982 Project Report

by Barbara Welch, Judy Potvin & Mary Ellen Dennis

Division of Environmental Evaluation and Lake Studies, Maine Department of Environmental Protection, Augusta, Maine 1982.

Contents: Understanding Maine's Lakes and Ponds / Acknowledgement / Temperature / Dissolved Oxygen / Other Measures of Lake Water Quality / Nutrients / Algae and Chlorophyll a / Transparency / Morphometry / Sampling / Protection / Classification / Answers to Most Frequently Asked Questions / Glossary of Terms / Appendix A : Maximum, Minimum, and Mean Values / Appendix B : Phosphate Content of Common Cleansers …


Diagenesis Of Organic Matter In Las Vegas Bay And Bonelli Bay, Lake Mead, James W. Murray, Carolyn J. Jones, Kathy Kuivila, Jeff Sawlan Jul 1981

Diagenesis Of Organic Matter In Las Vegas Bay And Bonelli Bay, Lake Mead, James W. Murray, Carolyn J. Jones, Kathy Kuivila, Jeff Sawlan

Publications (WR)

The interstitial water chemistry of the sediments of Las Vegas Bay and Bonelli Bay in Lake Mead has been studied as part of a comprehensive water quality study of those locations. Pore water and solid phase analyses were completed from four stations in Las Vegas Bay and two stations in Bonelli Bay. At both locations the pore water compositions and organic matter diagenesis in the sediments are dominated by sulfate reduction. This major role of sulfate reduction is unusual for lake sediments and reflects the fact that SO4 is the major anion in the lake water. In addition, gypsum …


Methods For Biological, Chemical, And Physical Analyses In Reservoirs, Penelope E. Kellar, Sherell A. Paulson, Larry J. Paulson Dec 1980

Methods For Biological, Chemical, And Physical Analyses In Reservoirs, Penelope E. Kellar, Sherell A. Paulson, Larry J. Paulson

Publications (WR)

This manual contains detailed descriptions of biological, chemical and physical sampling and analytical procedures used at the Lake Mead Limnological Research Center. The manual was prepared in response to requests made by numerous individuals involved in the Las Vegas Valley Water Quality Program. This manual represents what we consider to be a reasonably complete compilation of methods useful in studying both general and specific limnological questions. While each section is sufficiently detailed to be of use to investigators with little experience in limnological methodology, the methods can be used on a wide variety of lakes and reservoirs, with relatively little …


Nutrient Interactions Among Reservoirs On The Colorado River, Larry J. Paulson, John R. Baker Jun 1980

Nutrient Interactions Among Reservoirs On The Colorado River, Larry J. Paulson, John R. Baker

Publications (WR)

Interactions among physical, chemical and biological processes in reservoirs can significantly alter the characteristics of the discharge (Neel 1963, Wright 1967, Hannan 1979) that, in turn, can influence the ecology of the river downstream .(Ward and Stanford 1979). Investigations of the Colorado River, system reveal that reservoir-induced changes in the river can also affect downstream reservoirs. The formation of Lake Powell, in 1963 was accompanied by reductions in suspended sediment and nutrient loading and changes in the seasonal temperature and discharge cycles of the Colorado River. In this paper, we evaluate how these changes have influenced the nutrient and trophic …