Terrestrial and Aquatic Ecology Commons^™

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 …

Factors Affecting Reproductive Success Of Bonytail Chubs And Razorback Suckers In Lake Mohave, Michael A. Bozek, Larry J. Paulson, James E. Deacon, U.S. Department Of Interior, Fish And Wildlife Service

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Razorback suckers (Xyrauchen texanus) and bonytail chubs (Gila elegans) were once widespread throughout the Colorado River system. The ranges and populations of these native species and others have declined in the past 50 years. Bonytail chubs appear to be extremely rare and possibly nearing extinction in the Upper Colorado River Basin. The razorback sucker is widely distributed in the upper river but is considered rare throughout most of that range and is also rare in the Grand Canyon. Razorback suckers are abundant only in a few habitats in the upper river. They congregate and spawn over …

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

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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 …

Use Of Hydroelectric Dams To Control Evaporation And Salinity In The Colorado River System, Larry J. Paulson

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The main stem reservoirs on the Colorado River comprise one of the largest and most heavily used freshwater bodies in the nation. These reservoirs (Lake Powell, Lake Mead, Lake Mohave and Lake Havasu) can store up to 53,590,400 acre-feet of water at their maximum capacities. Nonetheless, local water shortages still exist in some areas of the Colorado River Basin. There is also concern that salt concentrations are approaching levels that could severely affect municipal and agricultural uses. Water shortages will become even more acute as demands for water increase with continued urban and agricultural development in the basin. Water conservation …

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

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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 …

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

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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 …

Influence Of Las Vegas Wash Density Current On Nutrient Availability And Phytoplankton Growth In Lake Mead, John R. Baker, Larry J. Paulson

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Density currents are commonly formed in reservoirs because of temperature or salinity induced density differences between inflowing and receiving waters. Anderson and Pritchard (1951) were among the first to demonstrate this in their investigations of density currents in Lake Mead. They found that the Colorado River formed an underflow in Lake Mead during the winter, an overflow in the spring and an interflow in the summer and fall. Wunderlich and Elder (1973) have since described the hydromechanics of these types of flow patterns, and density currents have been reported for several other large reservoirs (Carmack et al. 1979, Johnson and …

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

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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 …

Evaluation Of Impacts Associated With Reregulation Of Water Levels In Lake Mohave, Larry J. Paulson, John R. Baker, U.S. Water And Power Resources Service

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The U.S. Water and Power Resources Service is considering reregulating Lake Mohave water levels to increase the net power benefit from Hoover Dam. Reregulation will not increase the generation capacity of the Hoover powerplant but it will enable the plant operation to be increased when the energy has greater monetary value. Energy generated at different times of the year has different market value, the highest being in January-March and July- September. By generating more power during these periods more net monetary benefit can be derived from Hoover Dam. The total volume of water released from Hoover Dam over an annual …

Influence Of Dredging And High Discharge On The Ecology Of Black Canyon, Larry J. Paulson, Theron G. Miller, John R. Baker, U.S. Water And Power Resources Service

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The Water and Power Resources Service is considering dredging in Black Canyon to create a larger forebay to accommodate higher peak discharges and reverse flows for proposed modifications to Hoover Dam. The Black Canyon area from Hoover Dam to Willow Beach supports a heavily utilized trout fishery and is important habitat for the razorback sucker (Xyrauchen texanus) and possibly bonytail chub (Gila elegans). The Water and Power Resources Service initiated this investigation to determine what effect dredging and higher peak-discharges would have on the ecology of Black Canyon.

Limnological Aspects Of Lake Mead, Nevada-Arizona, John R. Baker, James E. Deacon, Thomas A. Burke, Samuel S. Egdorf, Larry J. Paulson, Richard W. Tew, Bureau Of Reclamation

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Lake Mead is a deep, subtropical, moderately productive, desert impoundment with a negative heterograde oxygen profile occurring during; the summer stratification. investigations of the Boulder Basin of Lake Mead by the University of Nevada were initiated in November 1971. The primary objective of the study was to determine what effects industrial and sewage effluent from the Las Vegas metropolitan area, discharged into Las Vegas Bay, have had on the water quality and limnological conditions of Boulder Basin. Data from the 1975-76 period are presented in detail, with earlier data included in the summaries and discussions. Measurements of water temperature, dissolved …

The Limnetic Zooplankton Community Of Boulder Basin, Lake Mead In Relation To The Metalimnetic Oxygen Minimum, Thomas A. Burke

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The limnetic zooplankton community of Boulder Basin, Lake Mead, was examined to determine the role of this community in the development of a metalimnetic oxygen minimum which regularly occurs in the lake. Analysis of the community from May 1975 to April 1976 revealed that zooplankton maintain high populations within the metalimnion during summer stratification. The species composition of the community changes noticeably during the summer, but due to advanced stages excysting from resting forms, a complete assemblage of individuals are found throughout the 74 day period studied. Thermal stratification was weak, covering a 30 meter metalimnion. Eddy currents powered by …

A Review Of The Limnology Of And Water Quality Standards For Lake Mead, Charles R. Goldman

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1. The waters of Las Vegas Bay, a heavily utilized recreational resource, receive discharges from a variety of municipal and industrial waste sources. The U.S. Environmental Protection Agency has determined, on the basis of numerous studies, that the present water quality violates state and federal standards and constitutes a public nuisance. Consultants have advised the Sewage and Wastewater Advisory Committee that rapid abatement of the alleged pollution conditions can be achieved by an advanced wastewater treatment (AWT) plant.

2. The major problems in Las Vegas Bay are an objectionable water color, excessive turbidity, noxious odors, and oxygen depletion in certain …

Report On Wastewater Disposal To Board Of County Commissioners, Clark County Nevada, Clair N. Sawyer

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This report is concerned with the management of waste-waters and subsurface drainage from the City of Las Vegas and its environs and the BMI complex, all in Clark County, Nevada. The prime objective is to recommend a plan of action which will utilize the natural resources of the area in the least costly manner and still protect Lake Mead for recreational purposes and use as a public water supply, At this writing, conditions in the upper Las Vegas arm of Boulder Basin are quite unsatisfactory for some recreational purposes due to the extensive blooms of algae which develop. Experience at …

Final Report - Lake Mead Monitoring Program, James E. Deacon

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The Lake Mead monitoring program has developed a substantial body of information on the physical, chemical and biological limnology of Lake Mead since 1972. This report summarizes pertinent aspects of that data, with emphasis on studies completed in 1975 -76. It is our continuing hope that the data developed by us will be useful to an ever broader group of users of the water resource represented by Lake Mead. We have been privileged to see our data have a significant influence in some very important water resource decisions over the past four years. There is every reason to expect that …

The Nature And Distribution Of Enteric Bacteria In Las Vegas Bay, Samuel S. Egdorf

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The distribution of water and of enteric bacteria of possible fecal origin into Las Vegas Bay from Las Vegas Wash was determined. Determination of distribution patterns was attained by applying the concept of the population component ratio of enteric bacteria. The development and application of new techniques and methods implicit in the application of the "component ratio" concept are discussed. The unreliability of thoroughly referenced techniques and methods generally accepted as standard are treated in detail. Physical factors affecting the distribution and deposition of enteric bacteria (including those of special public health importance) in Las Vegas Bay are also discussed.

Biological Inventory Of The Southern Nevada Water Project, Second Stage, W. Glen Bradley, J. Scott Miller

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The present report is a biological inventory of the Southern Nevada Water Project, Second Stage. The boundaries of the project encompass sections of North Las Vegas, Las Vegas, East Las Vegas and areas along Las Vegas Wash extending to its drainage point in Las Vegas Bay in Lake Mead. Therefore, it encompasses a wide array of ecological situations and landscapes ranging from essentially natural to various stages of urban development.

This biological inventory presents basic ecological classifications, descriptions of vegetation, lists of vascular plants and vertebrates known to occur in the area. Each major group, i.e., plants, fish, amphibians, reptiles, …

Seasonal And Spatial Variation In Primary Productivity In Boulder Basin, Lake Mead, Clark County, Nevada, Isamu Aoki

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The ¹⁴C light and dark bottle technique for measurement of primary production was utilized as a means of assessing the amount of inorganic carbon being converted Into organic form by the photosynthesis of phytoplankton populations In the Boulder Basin of Lake Mead.

Spatial and time series changes of productivity levels observed at eight sampling locations within Boulder Basin Indicate that the Influence of treated municipal arts' industrial effluent flowing into Les Vegas Bay is contributing high levels of available nutrients at Las Vegas Wash Inlet to cause productivity to approximate those levels associated with polluted waters.

Productivity levels at …

Biological Inventory In Conjunction With The Las Vegas Wash Unit, Colorado River Basin Salinity Control Act Title Ii (P.L. 93-320), W. Glen Bradley, J. Scott Miller

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The present report is a biological inventory in conjunction with the Las Vegas Wash Unit, Colorado River Basin Salinity Control Act, Title II. The boundaries of the project encompass sections of North Las Vegas, Las Vegas, East Las Vegas and areas along Las Vegas Wash extending to its drainage point in Las Vegas Bay in Lake Mead. Therefore, it encompasses a wide array of ecological situations and landscapes ranging from essentially natural to various stages of urban development. This biological inventory presents basic ecological classifications, descriptions of vegetation, lists of vascular plants and vertebrates known to occur in the area. …

A Diurnal Zooplankton Migration Study In Lake Mead, Robert D. Staker

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The diurnal vertical movement of zooplankton was first recorded in freshwater lakes by Weismann (1877) in Lake Constance (Bodensee), although Cuvier was credited with observing the migration of Daphniae in 1817 (Gushing, 1955). The migration is best observed in deep oligotrophic lakes and migrations of 50 m per day are described (Worthington, 1931). In addition, two species of chaetognaths are reported to migrate 400 m a day in marine waters off of Lisbon (Waterman and Berry, 1967) while Birge (1895) found little evidence of the phenomenon at all in Lake Mendota, Wisconsin. Most zooplankton that migrate rise at night and …

Phytoplankton Distribution And Water Quality Indices For Lake Mead (Colorado River), Robert D. Staker, Robert W. Hoshaw, Lorne G. Everett

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Phytoplankton samples were collected in Lake Mend 6 times from September 1910 to June 1971 for 8 stations at depths of 0. 3, 5, 10, 20, and 30 m. These samples were processed through a Millipore filter apparatus and 79 planktonic algae were identified. Algal divisions represented were Bacillariophyta, 42 species; Chlorophyta, 18 ; Cyanophyta, 9; Chrysophyta, 3; Cryptophyta, 3; Pyrrophyta, 2; and Euglenophyta, 2. Blue-green algae were dominant in late summer and fall; green algae, diatoms, and, cryptomonads in winter; and green algae in spring. The early summer flora was best represented by the Chlorophyta, Cryptophyta, and Chrysophyta. Palmer's …

Phytoplankton Successions And Lake Dynamics In Las Vegas Bay, Lake Mead, Nevada, Ervon R. Koening, Richard W. Tew, James E. Deacon

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Phytoplankton successions, applications of the general growth equation, and physical measurements have been employed to investigate events occurring at the interface between industrial and sewage effluent contained in Las Vegas Wash and the waters of Lake Mead, Nevada. The data indicate that the entering waters tend to form a density current interrupted at intervals by dynamic effects generated in the lake. The dynamic relationships described here for the spring months suggest that a much more thorough understanding of physical, chemical and biological interactions is necessary to permit solution of the numerous problems of Las Vegas Bay discussed or alluded to …

A Mathmatical Model Of Primary Productivity And Limnological Patterns In Lake Mead, Lorne G. Everett

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The temporal and spatial changes in chemical and biological properties of Lake Mead have been investigated, thereby indicating the sources of water pollution and the time of highest pollution potential. Planktonic organisms have been shown to indicate the presence of water problems. Macro- and micro-nutrient analyses have shown that primary productivity is not inhibited by limiting concentrations. A mathematical model has been developed, tested with one set of independent data, and shown worthy of management utility. Although the model works very well for the Lake Mead area, the physical reality of the Multiple Linear Regression equation should be tested on …

Report On Water Pollution Problems In Las Vegas Wash And Las Vegas Bay, Environmental Protection Agency

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This report was prepared by the Federal Water- Quality Administration, Pacific Southwest Region, now the Environmental Protection Agency (EPA), Region IX, at the request of the State of Nevada, Department of Health, Welfare, and rehabilitation. In a letter, dated December 5, 1969, this agency asked for technical assistance, as authorized by the Federal Water Pollution Control Act, in developing discharge standards appropriate for Las Vegas Bay, Lake Mead, and the Lower Colorado River. The subsequent study was performed by EPA from January through August, 1970. The establishment of Nevada State Water Quality Standards for these waters will enable responsible officials …

A Conceptual Draft Of A Dynamic Hydro-Biological Model For Lake Mead, L. G. Everett, Bureau Of Reclamation

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Food and energy transformation in an aquatic system must be understood in order to develop a simulation approach. This report provides a comprehensive study of an aquatic ecosystem. The objectives of this report are to show: (1) the biological relationships in an aquatic system (2) the role of nutrients in the biological cycle (3) the role of abiotic factors in a limnetic environment (4) the status of the art of "Eutrophication modeling".

The Effect Of Las Vegas Wash Effluent Upon The Water Quality In Lake Mead, D. A. Hoffman, P. R. Tramutt, F. C. Heller, Bureau Of Reclamation

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This study developed from observations made during an earlier study on Lake Mead which was reported in CHE-70, Water Quality Study of Lake Mead. Results from that study indicated that poor-quality water was flowing into the Las Vegas Bay reach of Boulder Basin, Lake Mead. Also reports of deteriorating water quality, resulting in taste and odors in domestic water supplies taken from Boulder Basin as well as a reduction in the attractiveness of Las Vegas Bay for recreational uses caused by aquatic plants and algae blooms, indicated a need for a concentrated study concerning the effects of flows from Las …

Biological Studies Of Selected Reaches And Tributaries Of The Colorado River, Nelson Thomas, Federal Water Pollution Control Administration

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This report fulfills the request of the Colorado River Basin Project, Denver, Colorado, to determine the effects of municipal and industrial wastes on the aquatic life in selected waters of the Colorado River Basin. These studies were conducted with the assistance of personnel from the Colorado River Basin Project.

Development, Verification, And Use Of Methods To Model Chemical And Thermal Processes Lakes Mead And Powell, Bureau Of Reclamation

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PURPOSE The purpose of the proposed research is to quantify the effects that Lakes Mead and Powell have on the salinity in the Colorado River system, and to evaluate changes that cap be made to the operating system of the reservoirs (within legal/institutional constraints) to enhance salt precipitation and/or minimize evaporation within the reservoirs. The effect of any changes (i.e., selective withdrawal uses, pumped storage, etc.) on reservoir evaporation could also be evaluated with a goal of minimizing evaporation. This will be accomplished through the development of a mathematical model of the reservoirs as described below. BACKGROUND Two major problems …

Water Chemistry Survey Of Boulder Basin, Lake Mead, P. R. Tramutt, Bureau Of Reclamation

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The survey results indicate that the impoundment of water behind Hoover Dam has not adversely affected the dissolved oxygen (DO) content and that water quality and DO content were uniform regardless of depth. The study made in April-May 1964 will provide water quality data of Lake Mead prior to releases from Lake Powell as a basis for evaluating Lake Powell's effect on water quality and limnology of Lake Mead. The performance of a DO analyzer was tested and found unsatisfactory at depths below 150 ft. Parameters tested by standard chemical analyses of water samples in the Denver Laboratory and by …

Preliminary Report: Monolayer Behavior Studies, 1959, Bureau Of Reclamation

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During the fall of 1959, monolayer behavior studies were made on two lakes in the southwest; Boulder Basin of Lake Mead, Nevada, and Lake Sahuaro near Phoenix, Arizona. These studies were made to evaluate the effect of geographical and climatological conditions on movement and behavior of monolayers. The Lake Sahuaro tests also were used to provide data for design and development of improved methods of application and maintenance of a film on this lake in anticipation of full scale, evaporation-reduction tests to be performed there during the summer of I960. The Lake Mead studies produced the following general points of …