Physical Sciences and Mathematics Commons^™

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 …

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.

Lake Mead Cover Enhancement Project, Jennifer Stevens Haley, Suzanne Leavitt, Larry Paulson, Donald H. Baepler

Publications (WR)

Ninety-three wildlife agencies were surveyed for information on their attempts to improve fish habitat. In addition, an annotated bibliography including over 100 summaries was completed on:

1. largemouth bass cover requirements and preferences,

2. use and effectiveness of artificial cover,

3. aquatic plant introduction and species requirements for germination and establishment,

4. terrestrial plant introduction and species requirements for germination and establishment, and

5. nutrient exchange between sediment, aquatic plants, and water.

A reconnaissance of existing terrestrial and aquatic vegetation was completed in June 1986 including the production of a video tape of the Nevada shoreline of Lake Mead.

Cover …

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.

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 …

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 …

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

Publications (WR)

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 Effects Of Impoundments On Salinity In The Colorado River, Larry J. Paulson, John R. Baker

Publications (WR)

The increase in salinity of our western rivers has been identified as one of the most serious water quality problems in the nation. This is of special concern in the Colorado River where salinity has increased from pristine levels estimated at 380 mg/1 to present-day levels of 825 mg/1 at Imperial Dam. Flow depletions, associated with decreased runoff and increased evaporation and diversions, coupled with high salt loading from natural and man-created sources are considered the primary causes for rising salinity in the river. The urban and agricultural development projected to occur in the basin through this century could deplete …

Final Report On Interrelationships Between Chemical, Physical And Biological Conditions Of The Waters Of Las Vegas Bay Of Lake Mead, James E. Deacon, Richard W. Tew

Publications (WR)

This program was a status study of the interaction between Las Vegas Wash, an enriched stream, and Las Vegas Bay, a wedge shaped arm of one of the world's deeper reservoirs. The program centered primarily on identification and counting of planktonic algae from several points in Las Vegas Bay. Additional work on nutrient enrichment of water samples was conducted to aid in interpretation of algal distribution related to nutrient input. Examination of a variety of physical, chemical, and biological parameters, both at many surface points in the bay, as well as in vertical profile, was also accomplished and further aided …

Micronutrients And Biological Patterns In Lake Mead, Hasan K. Qashu, Lorne G. Everett, J. S. Carlson, Bureau Of Reclamation

Publications (WR)

Progressive increases in concentration of dissolved solids in the Colorado River water from Lake Powell to Imperial Dam seem to alter plankton dynamics and biological productivity of the river. Also, changes in biological productivity and micronutrients concentrations occur within the same reservoir. Development of a digital simulation model to predict micronutrients concentrations and biological productivity is necessary for diagnosing changes in plankton population and effluent-carrying capacity of the system.

The objectives of the study are: (1) to determine trace metal balance at different locations in Lake Mead, (2) to measure biological productivity and conduct plankton population counts at each sampling …

Water Quality Study Of Lake Mead, Dale A. Hoffman, Paul R. Tramutt, Frank C. Heller, Bureau Of Reclamation

Publications (WR)

This report presents Lake Mead Water quality data obtained from 1964 to 1966. The effect of filling Lake Powell on the water quality of Lake Mead is evaluated. General limnological principles and the present limnology of Lake Mead are discussed. Lake Mead has a warm monomictic annual temperature cycle characterized by summer stratification, fall overturn leading into a continuous circulation throughout the winter; temperatures never fall below 39 deg F (4 deg C). During stratification, lower dissolved oxygen values were recorded in the thermocline than in the epilimnion and hypolimnion. Mineral content increases from the upper to the lower end …

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

Publications (WR)

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

Publications (WR)

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 …