Biology Commons^™

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 …

Temporal And Spatial Patterns Of Abundance Of Age 0 Threadfin Shad (Dorosoma Petenense) In Overton Arm, Lake Mead, William Lee Pelle

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Temporal and spatial patterns of age 0 threadfin shad (Dorosoma petenense) abundance and growth, in the Overton Arm of Lake Mead, were examined to evaluate the effects of resource availability on the young fish. This was part of a larger, game fishery enhancement study (Lake Mead Fertilization Project), designed to assess feasability of increasing survivorship of larval/juvenile shad by boosting phosphate levels, thereby increasing algal and zooplankton biomass, during the shad spawning period. Shad are the primary forage base for the striped bass (Morone saxatilis) and black bass (Macropterus salmoides) fisheries. Weekly samples were …

Limnological Monitoring Data For Lake Mead During 1988, Suzanne E. Leavitt, Larry J. Paulson, State Of Nevada: Division Of Environmental Protection

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Limnological monitoring was conducted in Las Vegas Bay and Boulder Basin from April to December of 1988. The purpose of the monitoring was to (i) document possible changes in water quality resulting from decreased phosphorus loading and increased ammonia in Las Vegas Wash, and (ii) establish a data base for evaluating the adequacy of water quality standards.

Red Swamp Crayfish Ecology In Lake Mead, Suzanne E. Leavitt, Jennifer Stephens Haley, Mikell Hager, Donald H. Baepler, Nevada Department Of Wildlife

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Red swamp crayfish (Procambarus clarkii) were trapped in Flamingo Wash, an urban wash of Las Vegas, during four periods of 1988. Life history and reproductive success were determined. The trapped crayfish were marked and released into a study cove in Lake Mead as part of an experimental stocking program. Retrap data from the study cove were used to determine life history, habitat preferences, and movement patterns of the stocked crayfish. In addition, a literature search was done on red swamp crayfish ecology, including food preferences, life history, habitat preferences and fish predation.

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

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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 …

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

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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 …

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

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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.

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

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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 …

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

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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.

Comparison Of Littoral And Limnetic Zooplankton Communities Of Lake Mead, Patrick Joseph Sollberger

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Microfaunal communities were studied in littoral (inshore) and limnetic (offshore) areas of the lower basin in Lake Mead to compare species composition and abundance between the two zones. Planktonic forms (zooplankton) dominated inshore and offshore habitats and the occurrence of littoral species was low. Therefore, high similarity in zooplankton species composition was found among all sampling stations. This was perhaps due to two main factors: (i) the physical and chemical environment among the stations were very similar and (ii) the lack of aquatic vegetation in the littoral zone reduced the occurrence of littoral species.

Although species composition did not vary …

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

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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 …

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 …

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 …

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 …

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.

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 …