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Salinity

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Articles 61 - 77 of 77

Full-Text Articles in Environmental Indicators and Impact Assessment

Bulletin No 4174 - Tree Planting On Farms In High Rainfall Areas, Ken Angell Jul 1990

Bulletin No 4174 - Tree Planting On Farms In High Rainfall Areas, Ken Angell

Bulletins 4000 -

Many of the techniques described in this Bulletin are applicable to broadacre farms. However, they are specifically directed to small rural properties in the high rainfall areas.

Trees can usually serve more than one purpose on small rural properties. They can be used as ornamentals, to provide shelter and shade, for erosion control, as a wildlife habitat, or for waterlogging and salinity control.


Saltland Management, Tim Negus Jan 1989

Saltland Management, Tim Negus

Natural resources published reports

Salt land problems in Western Australia are categorized into one of three types:

* Valley waterlogging

* hillside seepage

* dry land salt


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 …


Lake Mead Cover Enhancement Project, Jennifer Stevens Haley, Suzanne Leavitt, Larry Paulson, Donald H. Baepler Jul 1987

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 …


The Effects Of Impoundments On Salinity In The Colorado River, Larry J. Paulson, John R. Baker Jan 1983

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 …


Use Of Hydroelectric Dams To Control Evaporation And Salinity In The Colorado River System, Larry J. Paulson Jan 1983

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 …


An Ecological Analysis Of Relic Diatoms In Sediments Of Las Vegas Bay, Lake Mead, David Ross Hetzel Jul 1982

An Ecological Analysis Of Relic Diatoms In Sediments Of Las Vegas Bay, Lake Mead, David Ross Hetzel

Publications (WR)

Relic diatoms in sediments of the inner Las Vegas Bay, near the Las Vegas Wash sewage inflow, were examined in order to assess historic trophic conditions in this area of Lake Mead. Diatom sedimentation rates and ratios of Araphidineae/Centrales (A/C) diatom groups were determined from sediment cores collected in the old wash channel 1.5 km from the sewage inflow (station 2), in a small cove 1.5 km further downstream (station 3) and in an adjacent embayment off Gypsum Wash (station 4). Diatom sedimentation rates generally increased from the bottom to the top of each core, but pronounced minima existed at …


Influence Of Las Vegas Wash Density Current On Nutrient Availability And Phytoplankton Growth In Lake Mead, John R. Baker, Larry J. Paulson Jun 1980

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

Publications (WR)

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 Jun 1980

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

Publications (WR)

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 …


Lake Mead And Lake Powell Salinity Reports, Cathy Lee, Steve Gazafy Feb 1979

Lake Mead And Lake Powell Salinity Reports, Cathy Lee, Steve Gazafy

Publications (WR)

The enclosed reports were compiled for the Colorado River Water Quality Office based on salinity data for Lake Mead and Lake Powell. According to the regional director of the office, the reports are not considered "polished" documents for public distribution. However, he considers them to be "interesting, rough appraisals of general trends that may be very important In our understanding the hydro-salinity system in the Colorado River."


The Causes Of Saltland : A Case Study At Esperance, P R. George, S. C. Bull Jan 1979

The Causes Of Saltland : A Case Study At Esperance, P R. George, S. C. Bull

Journal of the Department of Agriculture, Western Australia, Series 4

A series of bores on the Esperance Downs Research Station has demonstrated that the groundwater levels change after clearing, and the relatiojnnship between groundwater levels and soil salinity has been emphasised. This pattern of hydrological change leading to soil salinity problems applies widely in the wheatbelt.


Landform, Natural Drainage And Salinity, Eric Bettenay Jan 1978

Landform, Natural Drainage And Salinity, Eric Bettenay

Journal of the Department of Agriculture, Western Australia, Series 4

An understanding of salt movement in streams and groundwater may lead to better methods of control and prevention of salinity.


Soil Salinity In Western Australia : A Summary, T C. Stoneman Jan 1978

Soil Salinity In Western Australia : A Summary, T C. Stoneman

Journal of the Department of Agriculture, Western Australia, Series 4

Soil salinity problems have long been recognised in Western Australia. The earliest published explanation in 1924 suggested that removing native vegetation increased stream salinity, and this basic cause has been confirmed by many studies since.


The Dryland Salinity Problem In North America, P R. George Jan 1978

The Dryland Salinity Problem In North America, P R. George

Journal of the Department of Agriculture, Western Australia, Series 4

North america also has a dryland salinity problem although the source is different.


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 …


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 …