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Articles 1351 - 1357 of 1357

Full-Text Articles in Natural Resources and Conservation

Water Quality Study Of Lake Mead, Dale A. Hoffman, Paul R. Tramutt, Frank C. Heller, Bureau Of Reclamation Nov 1967

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 Jul 1966

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 …


Fisheries Report No 3 - Western Australian Freshwater Fisheries, Donald D. Francois Jan 1966

Fisheries Report No 3 - Western Australian Freshwater Fisheries, Donald D. Francois

Fisheries Research Reports

Most of the Australian States have a comprehensive system of inland waterways, Western Australia, however, is in a less fortunate position. True, the maps of the State show many rivers, but in much of the southern, more populous part, with no summer rain and no winter snow, the majority are virtually a chain of waterholes during the long summer months. At the same time, in a relatively small section in the south-west corner, there is a series of permanent streams flowing through what was originally dense forest. But apart from the three indigenous freshwater crustaceans, the marron (Cherax tenuimanus), the …


Water Chemistry Survey Of Boulder Basin, Lake Mead, P. R. Tramutt, Bureau Of Reclamation Jun 1965

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 …


Available Water Supply Of The Las Vegas Ground-Water Basin Nevada, Glenn Thomas Malmberg Jan 1965

Available Water Supply Of The Las Vegas Ground-Water Basin Nevada, Glenn Thomas Malmberg

Publications (WR)

The Las Vegas ground-water basin as described in this report includes the southern part of Indian Spring Valley, Three Lakes Valley, the northern half of Ivanpah Valley, and Las Vegas Valley. These valleys in part are inferred to form a hydrologic unit that includes an area of about 3,000 square miles in the southern part of Clark County, Nev.

The valleys forming the Las Vegas ground-water basin are broad structural depressions surrounded by mountains. The climate of the region is arid, and precipitation in the basin lowlands rarely exceeds 5 inches per year. Drainage is interior except for occasional Hood …


Fisheries Report Ii (2) - Preliminary Report On The Effectiveness Of Escape-Gaps In Crayfish-Pots, B. K. Bowen Jan 1963

Fisheries Report Ii (2) - Preliminary Report On The Effectiveness Of Escape-Gaps In Crayfish-Pots, B. K. Bowen

Fisheries Research Reports

The Western Australian commercial crayfish, Panulinrus cy,nus George, (1962)", is caught in depths ranging from a few feet to approximately 45 fathoms. In the shallow waters large numbers of crayfish measuring, less than the legal minimum length are brought to the surface in the standard commercial crayfish pots. The law requires that these undersize crayfish be returned to the sea, but there is always the temptation to retain them for illegal sale. In addition, the undersize crayfish which are returned to the sea are often damaged by handling. The probability is that their mortality rate is higher than those which …


Preliminary Report: Monolayer Behavior Studies, 1959, Bureau Of Reclamation Jan 1960

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

Publications (WR)

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 …