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Articles 241 - 270 of 308

Full-Text Articles in Natural Resources and Conservation

Vegetation Analysis: A Graphical Analysis Of Plant Succession In Desert Communities Affected By Fire, Jeff Lantow Oct 1998

Vegetation Analysis: A Graphical Analysis Of Plant Succession In Desert Communities Affected By Fire, Jeff Lantow

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Mojave Desert is affected by fire every year. With each fire comes the removal of old growth and, in its place, new growth – consisting primarily of those species which thrive in disturbed areas. The focus of my research is to look at plant communities that have been disturbed by fire, and examine the successional pathway of these disturbed environments. The seven environments I analyzed were burned within the last twenty years and are found in the Coleogyne ramosissima ecotone throughout the Spring Mountain range near Las Vegas, Nevada. The data was collected with randomly chosen circle plots in …


Water Conservation In The Las Vegas Valley, Judith M. Keir Oct 1998

Water Conservation In The Las Vegas Valley, Judith M. Keir

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis deals primarily with residential use of water in the Las Vegas Valley, an arid climate located in the Mojave Desert, and whether the education of people living here has any bearing on whether or not they conserve water. Many of the residents of the Las Vegas Valley have moved from other areas of the country, and perhaps are not aware of the fact that there is a limited supply of water available to the Valley. I believe that people are not necessarily wasteful, and that they would want to conserve water, if they were aware that conservation and …


Lead Shot Concentration In Soil At The Overton Wildlife Management Area, Nevada, George R. Bertoty Oct 1998

Lead Shot Concentration In Soil At The Overton Wildlife Management Area, Nevada, George R. Bertoty

UNLV Theses, Dissertations, Professional Papers, and Capstones

During the spring of 1998, soil samples were collected from two areas at the Overton Wildlife Management Area (OWMA), located in the Moapa Valley of Clark County, Nevada. Lead shot has been banned for the hunting of waterfowl since 1986 but is still legal for upland game hunting. Both types of hunting occur at OWMA. One area sampled is a cultivated field and serves primarily as a dove hunting area. The other area is primarily a waterfowl hunting area and is flooded during the waterfowl-hunting season. Lead shot was recovered from 83% of the samples from the dove hunting area, …


Interagency Lake Mead And Las Vegas Wash Monitoring Program: Standard Operating Procedures Manual, Bureau Of Reclamation, City Of Henderson Water Reclamation Facility, City Of Las Vegas Water Pollution Control Facility, Clark County Sanitation District, Nevada, Southern Nevada Water Authority Oct 1998

Interagency Lake Mead And Las Vegas Wash Monitoring Program: Standard Operating Procedures Manual, Bureau Of Reclamation, City Of Henderson Water Reclamation Facility, City Of Las Vegas Water Pollution Control Facility, Clark County Sanitation District, Nevada, Southern Nevada Water Authority

Publications (WR)

A number of agencies sample Lake Mead and the Las Vegas Wash on a routine basis at several locations. In order to share and properly interpret the data, the Bureau of Reclamation, Southern Nevada Water Authority and the three Wastewater Treatment Facilities (City of Las Vegas, Clark County Sanitation District and City of Henderson) formed a committee to examine sampling and analytical protocols and to share information with the goal of maximizing the data quality. The group first met in April 1997. It was agreed that an effort should be made to discuss and compare specific sampling and analytical techniques …


Artificial Recharge In The Las Vegas Valley: An Operational History, Michael Johnson, Erin Cole, Kay Brothers, Las Vegas Valley Water District Jun 1997

Artificial Recharge In The Las Vegas Valley: An Operational History, Michael Johnson, Erin Cole, Kay Brothers, Las Vegas Valley Water District

Publications (WR)

Artificially recharging the Las Vegas Valley (Valley) ground-water system with treated Colorado River water is one water resource management option employed by the Las Vegas Valley Water District (District) to help meet future long-term and short-term peak water demands. The District began operation of an artificial ground-water recharge program in 1988 in order to bank water for future use and to slow declining water levels. Artificial recharge occurs in the winter months, typically from October to May, when there is excess capacity in the Southern Nevada Water System (SNWS), currently a 400 Million Gallon per Day (MGD) treatment and transmission …


Las Vegas Wash Water Quality Monitoring Program: 1996 Report Of Findings, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation, U.S. Geological Survey Apr 1997

Las Vegas Wash Water Quality Monitoring Program: 1996 Report Of Findings, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation, U.S. Geological Survey

Publications (WR)

Las Vegas Wash, a natural wash east of the city of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from three sewage treatment plants to Lake Mead. The Wash provides nearly the only surface water outlet for the entire 2,193 mi2 of Las Vegas Valley. A drainage area of 1,586 mi2 contributes directly to the Wash through surface flow which is channeled to Las Vegas Bay of Lake Mead, while drainage of the remaining 607 mi2 is presumably subsurface and may drain toward Las Vegas Wash.

In the 1930's and 1940's, sewage treatment plants were …


Composting Landscape Waste From The University Of Nevada, Las Vegas, K. Jill Hammond Mar 1997

Composting Landscape Waste From The University Of Nevada, Las Vegas, K. Jill Hammond

UNLV Theses, Dissertations, Professional Papers, and Capstones

The University of Nevada, Las Vegas is a major producer of organic waste in the Las Vegas Valley. Composting landscape wastes is one way to reduce both landfill dumping and fertilizer costs for the university. It is also an environmentally friendly means of curbing a nationwide problem: unnecessary use of landfill space. Three sites within Clark County were analyzed for the feasibility of composting: Frenchman Mountain, UNLV Campus, and Boulder City Landfill. Using cost analysis, water availability, and other factors to analyze each site, Boulder City Landfill appears to be the best place to house UNLV's composting operation. Composting in …


Las Vegas Flamigo Hilton/Unlv Environmental Studies Program Environmental Resource Analysis & Optimization Plan, Dennis Nowlin Jul 1996

Las Vegas Flamigo Hilton/Unlv Environmental Studies Program Environmental Resource Analysis & Optimization Plan, Dennis Nowlin

UNLV Theses, Dissertations, Professional Papers, and Capstones

From 1987 through 1992 the Las Vegas Flamingo Hilton instituted resource efficiency improvements in electrical, natural gas, water and materials consumption. In 1992, the Flamingo Hilton commissioned the University of Nevada Las Vegas Environmental Studies Department to analyze and quantify the improvements made by The Flamingo Hilton and investigate the potential for further improvements.

Historical billing data from the periods 1987 - 1992 were used to analyze past and present (1992) electric, natural gas and water consumption. Materials disposal data was only available for a ten month period in 1992. Pollutant emissions data were supplied by Nevada Power Company.

The …


The Real Cost Of Beef: A Monetary Assessment Of The Environmental Degradation Caused By Beef Production, Carolyn Babcock Jul 1996

The Real Cost Of Beef: A Monetary Assessment Of The Environmental Degradation Caused By Beef Production, Carolyn Babcock

UNLV Theses, Dissertations, Professional Papers, and Capstones

The environmental degradation caused by beef production is severe. The current literature assesses the ecological damage, but falls short of assigning a per pound dollar amount to reflect the real cost of beef. In the United States, most of the environmental focus has been centered around the use of public lands for grazing and the grazing fee the government considers appropriate. The fee covers the maintenance of the grazing program, which includes maintenance of the actual land. This paper will concentrate on beef-related environmental degradation and select specific damage for monetary valuation.


Report Of Significant Findings--Las Vegas Bay/Boulder Basin Investigations, James F. Labounty, Michael Horn, Bureau Of Reclamation Apr 1996

Report Of Significant Findings--Las Vegas Bay/Boulder Basin Investigations, James F. Labounty, Michael Horn, Bureau Of Reclamation

Publications (WR)

Field sampling was carried out between 0830 and 1500 beginning at the confluence of Las Vegas Wash and the Inner Las Vegas Bay. Ten (10) locations were sampled, each in a similar manner. Locations of sampling stations are in line from the Wash-Bay confluence to a point midway between Saddle and Black Islands. In addition, sampling was done at a location midway between Sentinel Island and the base of Fortification Hill, and at the buoy line in front of Hoover Dam. Sampling stations are labeled from LV01, at Wash-Bay confluence, to LV17 at Hoover Dam. A significant data collection point …


An Analysis Of Remediation Alternatives In An Attempt To Establish An Effective Hydrocarbon-Contaminated Soils Remediation Program At The Yucca Mountain Site Characterization Project (Ymp), Marc A. Gonzales Apr 1996

An Analysis Of Remediation Alternatives In An Attempt To Establish An Effective Hydrocarbon-Contaminated Soils Remediation Program At The Yucca Mountain Site Characterization Project (Ymp), Marc A. Gonzales

UNLV Theses, Dissertations, Professional Papers, and Capstones

An analyses, of six (6) soil remediation alternatives was completed in attempt to establish an effective hydrocarbon-contaminated soils remediation program at the Yucca Mountain Site Characterization Program (YMP). The remediation alternatives analyzed included: no remediation, on-site incineration, off-site incineration, in-situ .bioremediation, ex-situ bioremediation, and excavation and disposal. Variables considered in the evaluation process included cost of contaminated soil transportation, treatment costs, future liability, and success of remediating the contaminated soils to below regulatory thresholds. The analysis concluded in the recommendation of an on-site ex-situ bioremediation treatment facility (BTF) to remediate hydrocarbon-contaminated soils at the YMP. The selection was based on …


Synthetic Organic Compounds: Las Vegas Wash And Lake Mead, National Water Quality Assessment Program (Nawqa): Nevada Basin And Range Jan 1996

Synthetic Organic Compounds: Las Vegas Wash And Lake Mead, National Water Quality Assessment Program (Nawqa): Nevada Basin And Range

Publications (WR)

The Nevada Basin and Range (NVBR) study unit of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program is investigating the status of, trends in, and factors affecting water quality in the Las Vegas area. A principal objective of the investigation is to assess the effects of urbanization on the quality of area water resources. Las Vegas Wash is the surface-water outlet for the Las Vegas area. The wash transports stormwater runoff, shallow ground-water discharge, and tertiary-treated sewage effluent from the Las Vegas area to Las Vegas Bay of Lake Mead on the Colorado River. Most of the flow—about 96 …


Nutrient Limitation In A Southwestern Desert Reservoir: Eutrophication Of Las Vegas Bay, Lake Mead, Nevada, Davine M. Lieberman Sep 1995

Nutrient Limitation In A Southwestern Desert Reservoir: Eutrophication Of Las Vegas Bay, Lake Mead, Nevada, Davine M. Lieberman

Publications (WR)

Algal bioassay tests were conducted with Selenastrum capricornutum and natural algae on inner Las Vegas Bay, Lake Mead, Nevada, from December 1992 through September 1993, to identify any nutrient limitation in an area of the reservoir that has experienced problems associated with severe nutrient enrichment. Three areas were sampled based on a gradient of water quality conditions that existed in Las Vegas Bay (LVB). Disodium ethylenedinitrilotetraacetate (EDTA) significantly stimulated algal growth compared to non-EDTA treatment. Algal bioassays indicated that phosphorus (P) was the primary limiting nutrient at all stations for most of the test dates. Chl a response with EDTA …


Limiting Growth In Las Vegas - A Necessary Growth Strategy For The Twenty-First Century, Cheryl Ann Frassa Apr 1995

Limiting Growth In Las Vegas - A Necessary Growth Strategy For The Twenty-First Century, Cheryl Ann Frassa

UNLV Theses, Dissertations, Professional Papers, and Capstones

Land development in the Las Vegas Valley continues at an unprecedented rate and future growth will no doubt be strongly advocated. Yet, water resources in this desert area are finite, and in the near future, supply will fall short of demand. Plans are underway to supplement the existing supply, and proposals to secure additional sources are under investigation. But there are no guarantees these ambitious endeavors will materialize. In light of the pending water crisis, the pervasive "growth at all cost" policies now dominant in the valley must be abandoned and more realistic land-use policies developed; ones based on the …


Baseline Water Quality Data Inventory And Analysis: Lake Mead National Recreation Area, Volume Ii Of Ii, National Park Service Dec 1994

Baseline Water Quality Data Inventory And Analysis: Lake Mead National Recreation Area, Volume Ii Of Ii, National Park Service

Publications (WR)

This document presents the results of surface-water-quality data retrievals for Lake Mead National Recreation Area (LAME) from five of the United States Environmental Protection Agency's (EPA) national databases: (1) Storage and Retrieval (STORET) database management system; (2) River Reach File (RF3); (3) Industrial Facilities Discharge (IFD); (4) Drinking Water Supplies (DRINKS); and (5) Flow Gages (GAGES). This document is one product resulting from a cooperative contractual endeavor between the National Park Service's Servicewide Inventory and Monitoring Program, the National Park Service's Water Resources Division (WRD), and Horizon Systems Corporation to retrieve, format, and analyze water quality data for all units …


Baseline Water Quality Data Inventory And Analysis: Lake Mead National Recreation Area, Volume I Of Ii, National Park Service Dec 1994

Baseline Water Quality Data Inventory And Analysis: Lake Mead National Recreation Area, Volume I Of Ii, National Park Service

Publications (WR)

This document presents the results of surface-water-quality data retrievals for Lake Mead National Recreation Area (LAME) from five of the United States Environmental Protection Agency's (EPA) national databases: (1) Storage and Retrieval (STORET) database management system; (2) River Reach File (RF3); (3) Industrial Facilities Discharge (IFD); (4) Drinking Water Supplies (DRINKS); and (5) Flow Gages (GAGES). This document is one product resulting from a cooperative contractual endeavor between the National Park Service's Servicewide Inventory and Monitoring Program, the National Park Service's Water Resources Division (WRD), and Horizon Systems Corporation to retrieve, format, and analyze water quality data for all units …


Southern Nevada Effluent Wetlands: A Proposed Cooperative Venture Between The Bureau Of Reclamation & City Of Las Vegas, Bureau Of Reclamation Nov 1992

Southern Nevada Effluent Wetlands: A Proposed Cooperative Venture Between The Bureau Of Reclamation & City Of Las Vegas, Bureau Of Reclamation

Publications (WR)

Throughout North America there is a growing interest in constructed wetlands, both as relatively inexpensive, low-maintenance systems for removing nutrients from wastewater, and as a means of using municipal wastewater to enhance wildlife habitat and create public use opportunities. Because wetlands appear to have good potential as a component in the overall management of scarce water resources, the Bureau of Reclamation (Reclamation) has undertaken several cooperative research and demonstration projects to evaluate their effectiveness in a variety of local environments. While a number of projects have demonstrated that wetlands can be beneficially employed to improve water quality, few such projects …


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 …


Lake Mead Nutrient Enhancement Project, Peter D. Vaux, Larry J. Paulson, Nevada Department Of Wildlife, National Oceanic And Atmospheric Administration Dec 1990

Lake Mead Nutrient Enhancement Project, Peter D. Vaux, Larry J. Paulson, Nevada Department Of Wildlife, National Oceanic And Atmospheric Administration

Publications (WR)

The Lake Mead Fertilization Project is a research program designed to investigate the potential for using large-scale artificial fertilization to enhance the game fisheries of this reservoir through an increase in the population of threadfin shad, the system's primary forage species. A substantial decline in the population of largemouth bass, together with poor condition of adult striped bass, are the two major issues affecting the Lake Mead game fisheries. Both issues have been hypothesized to be a result of an inadequate amount of forage in the reservoir. Previous studies have in turn suggested that a major factor limiting the shad …


Temporal And Spatial Variation In Pelagic Fish Abundance In Lake Mead Determined From Echograms, Gene R. Wilde, Larry J. Paulson Jan 1989

Temporal And Spatial Variation In Pelagic Fish Abundance In Lake Mead Determined From Echograms, Gene R. Wilde, Larry J. Paulson

Publications (WR)

Echograms have been used extensively to locate and estimate the relative abundance of marine fish stocks (Cushing 1973). In freshwater, echograms have been used to describe vertical (Netsch et al. 1971; Eggers 1978; O'Brien et al. 1984; Matthews et al. 1985), spatial (O'Brien et al. 1984; Wanjala et al. 1986) and temporal (Baker and Paulson 1983) patterns in fish abundance. Although most uses of echograms have been qualitative, Mullan and Applegate (1969) and Matthews et al. (1985) obtained relative estimates of fish abundance by counting targets (fish) on echograms. However, neither Mullan and Applegate (1969) nor Matthews et al. (1985) …


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 …


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 …


River Discharge Study, Laughlin, Nevada: Colorado River Model And Diffusion Study, B. Dennis Hugh, David L. Stringfield, Jill C. Bicknell, Robert A. Ryder, Clark County Sanitation District, Nevada Jan 1988

River Discharge Study, Laughlin, Nevada: Colorado River Model And Diffusion Study, B. Dennis Hugh, David L. Stringfield, Jill C. Bicknell, Robert A. Ryder, Clark County Sanitation District, Nevada

Publications (WR)

A water quality modeling study of the Mohave Reach of the Lower Colorado River (from Davis Dam to the Nevada/California Stateline) was conducted to evaluate potential water quality impacts resulting from a proposed Laughlin, Nevada wastewater effluent discharge. The study included four major components: (1) review of the current regulatory framework; (2) a field data collection program to document existing water quality conditions in winter, summer, and fall; (3) development and verification of far-field and near-field (mixing zone) water quality models; and (4) application of the models to project future river quality conditions for several treatment-discharge alternatives as well as …


Fish Aid: The Lake Mead Fertilization Project, Richard Axler, Larry Paulson, Peter Vaux, Patrick Sollberger, Donald H. Baepler Jan 1988

Fish Aid: The Lake Mead Fertilization Project, Richard Axler, Larry Paulson, Peter Vaux, Patrick Sollberger, Donald H. Baepler

Publications (WR)

Sport fishing at Lake Mead in Nevada and Arizona is a resource valued at nearly $100 million per year to southern Nevada. During the past two decades, salmonids, mostly trout, have disappeared entirely, the largemouth bass catch has drastically declined despite greater fishing pressure, and the condition factors for striped bass have steadily deteriorated. It appears that a major reduction in phosphorus loading caused by the upstream impoundment of the Colorado River to form Lake Powell in 1963 and advanced wastewater treatment removal of phosphorus from domestic wastewater inflows in 1981 are the principal factors responsible for decreased production at …


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 …


River Discharge Study, Laughlin, Nevada: Field Survey Data, 1987, B. Dennis Hugh, David L. Stringfield, Jill C. Bicknell, Robert A. Ryder, Clark County Sanitation District, Nevada Dec 1987

River Discharge Study, Laughlin, Nevada: Field Survey Data, 1987, B. Dennis Hugh, David L. Stringfield, Jill C. Bicknell, Robert A. Ryder, Clark County Sanitation District, Nevada

Publications (WR)

A report of the first field data collection effort for the Laughlin River Discharge Study, conducted by Kennedy/Jenks/ChiIton in February, 1987, on the Mohave Reach of the Colorado River. This report also serves to transmit the laboratory analysis reports for all of the analyses performed and summary tables of the results. This report is organized as follows: 1. Field Conditions and Methodology 2. Summary of Sampling and Analysis Results 3. Deviations from the Proposed Sampling Program 4. Recommendations for Future Sampling 5. Attachments: A. Climatological Data B. Davis Dam Average Hourly Releases C. Laboratory Analysis Reports


Lake Mead Prefertilization Study: Preliminary Nutrient Enhancement Studies In Lake Mead, Richard P. Axler, Larry J. Paulson, Patrick J. Sollberger, Donald H. Baepler, U.S. Bureau Of Reclamation Nov 1987

Lake Mead Prefertilization Study: Preliminary Nutrient Enhancement Studies In Lake Mead, Richard P. Axler, Larry J. Paulson, Patrick J. Sollberger, Donald H. Baepler, U.S. Bureau Of Reclamation

Publications (WR)

Studies conducted by the University of Nevada-Las Vegas (UNLV), the Nevada Department of Wildlife (NDOW), the Arizona Game and Fish Department (AGFD), The Nevada Division of Environmental Protection (NDEP), and the United States Bureau of Reclamation (USBR) have identified decreased algal production as a major factor involved in the decline of the Lake Mead sport fishery. Phosphorus-laden silt particles in the Colorado River have been sedimenting out in Lake Powell since the completion of Glen Canyon Dam 286 miles upstream in 1963. This sharp decrease in phosphorus loading to Lake Mead (>5000 tons per year) has resulted in decreased …


Thermal Tolerances And Preferences Of Fishes Of The Virgin River System (Utah, Arizona, Nevada), James E. Deacon, Paul B. Schumann, Edward L. Stuenkel Oct 1987

Thermal Tolerances And Preferences Of Fishes Of The Virgin River System (Utah, Arizona, Nevada), James E. Deacon, Paul B. Schumann, Edward L. Stuenkel

Publications (WR)

Critical thermal maxima (CTM) and thermal preferenda of the common fishes of the Virgin River were examined. Differences in final temperature preferenda and CTM for species with low thermal lability (speckled dace, spinedace, roundtail chub) correspond well with differences in their distribution and abundance in the river. These species shifted their acute thermal preferences relatively little as acclimation temperature increased. For thermally labile species (woundfin, red shiner, desert sucker, and fiannehnouth sucker), the final preferendum is a less precise indicator of probable distribution. The woundfin, an endangered fish, has a high CTM (39.5 C at 25 C acclimation) and a …


Benthic Invertebrates And Crayfish Of Lake Mead, Susan K. Peck, William L. Pratt, James E. Pollard, Larry J. Paulson, Donald H. Baepler Sep 1987

Benthic Invertebrates And Crayfish Of Lake Mead, Susan K. Peck, William L. Pratt, James E. Pollard, Larry J. Paulson, Donald H. Baepler

Publications (WR)

The objectives of this study were to:

1. Establish baseline densities of benthic invertebrates and relative abundance of crayfish in Lake Mead.

2. Evaluate the distributions of benthic organisms and crayfish in relation to existing habitat conditions and 1imnological characteristics of Lake Mead.

3. Measure seasonal changes in abundances of benthic organisms and crayfish in Lake Mead.

4. Compare observations of Procambarus clarkii life history in Lake Mead to reports from other aquatic systems.

5. Evaluate the importance of benthic organisms and crayfish as food sources for game fish in Lake Mead.


Analysis Of The Water-Quality Standards Proposed By The Nevada Division Of Environmental Protection, City Of Las Vegas, Nevada Aug 1987

Analysis Of The Water-Quality Standards Proposed By The Nevada Division Of Environmental Protection, City Of Las Vegas, Nevada

Publications (WR)

The Nevada Division of Environmental Protection (DEP) has proposed water-quality standards, applicable to Las Vegas Bay and Lake Mead, for (1) chlorophyll, (2) un-ionized ammonia, and (3) pH.

We have concluded that the proposed standards are unlikely to protect or improve water quality in Lake Mead. The proposed chlorophyll standard:

May harm the fishery. Lakes with more chlorophyll have greater fish production.

Will not improve clarity. Chlorophyll concentrations above 30 ug/1 have little effect on clarity.

Will not protect against scums or dominance by blue-green algae. Lake Mead shows no consistent relationship between chlorophyll and scums or blue-green dominance.

Will …