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Articles 2071 - 2100 of 2388

Full-Text Articles in Fresh Water Studies

Annual Medics For The Kalgoorlie Region And Adjacent Eastern Rangeland Zones, G Gintzburger Jan 1983

Annual Medics For The Kalgoorlie Region And Adjacent Eastern Rangeland Zones, G Gintzburger

Experimental Summaries - Plant Research

Species selection and establishment methods Extensive overgrazing and burning of the dominant winter rainfall Goldfields pastoral zones have left large areas degraded with a poor annual vegetation cover of nearly no grazing value. Thus, more grazing pressure is exerted on shrubs and small trees accelerating the desertification process. Shrubs and trees are the main stabilising agent left in a rangeland plant community when alI annuals have been grazed out. In order to upgrade or regenerate some of these areas, conventional methods of grazing prohibition or deferred grazing can be used but often, improvement obtained are slow. It is hypothesized that …


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 …


Historical Patterns Of Phytoplankton Productivity In Lake Mead, Richard T. Prentki, Larry J. Paulson Jan 1983

Historical Patterns Of Phytoplankton Productivity In Lake Mead, Richard T. Prentki, Larry J. Paulson

Publications (WR)

Lake Mead was impounded in 1935 by the construction of Hoover Dam. The Colorado River was unregulated prior to then and therefore was subjected to extreme variations in flows and suspended sediment loads. Hoover Dam stabilized flows and reduced suspended sediment loads downstream, but Lake Mead still received silt-laden inflows from the upper Colorado River Basin. The Colorado River contributed 97% of the suspended sediment inputs to Lake Mead, and up to 140 x 1O6 metric tons (t) entered the reservoir in years of high runoff. Most of the sediments were deposited in the river channel and formed an …


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 Jan 1983

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

Publications (WR)

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 …


Raw Water Quality In The New Charleston, Illinois Pump Storage Reservoir, Kevin G. Lookis Jan 1983

Raw Water Quality In The New Charleston, Illinois Pump Storage Reservoir, Kevin G. Lookis

Masters Theses

Charleston, Illinois, a city located in east-central Illinois, recently implemented a new concept in a raw water system. Due to storage capacity-sedimentation problems in the old Lake Charleston-Embarras River raw water supply, the Charleston Pump Storage Reservoir was constructed. The new system involved building a dike separating the Lake Charleston impoundment from the Embarras River. Water to increase the storage capacity of the reservoir can now be selectively pumped into the impoundment from the river.

Raw water quality in the reservoir was monitored on a weekly basis for a full year from August, 1981 to August, 1982. The levels of …


The Application Of Laser Intracavity Absorption Detector To Gas Chromatography Of Trace Organic Pollutants In Water, Robert B. Green Dec 1982

The Application Of Laser Intracavity Absorption Detector To Gas Chromatography Of Trace Organic Pollutants In Water, Robert B. Green

Arkansas Water Resources Center Technical Reports

A helium-neon (HeNe) laser operating simultaneously at 3.39 um (infrared) and 0.63 um (visible) has been used as a selective detector for hydrocarbons in the effluent of a gas chromatograph. The infrared and visible laser transitions originate at the same energy level and are competitive. When a hydrocarbon enters the laser's resonant cavity, the 3.39 um energy is absorbed due to the C-H stretching vibration and the visible emission is enhanced. The visible laser emission is monitored with a photodiode as a quantitative measure of the concentration of the absorbing molecule. The minimum detectable concentration for propane using the double-beam …


Effects Of Wastewater Discharges On Periphyton Growth In Lake Mead, Nevada-Arizona, Marsha Korb Morris Dec 1982

Effects Of Wastewater Discharges On Periphyton Growth In Lake Mead, Nevada-Arizona, Marsha Korb Morris

Publications (WR)

A study of the effects of secondary-treated wastewater on periphyton growth in Lake Mead, Nevada-Arizona was conducted from September 1979 to December 1980. Periphyton ash-free dry weight, chlorophyll-a, dominant species composition, and alkaline phosphatase activity were measured on fiberglass substrates. Substrates were incubated for two to four weeks in littoral and limnetic habitats. Physical and chemical variables and phytoplankton chlorophyll-a were measured concurrently.

Transparency increased with increasing distance from the discharge. Secchi depth ranged from 0.75 m at the discharge confluence (station 2) in August, to greater than 20 m at the most distant stations (stations 9 and 10) in …


A Faunal And Seasonal Study Of The Aquatic Insects In Two Water Ecosystems In South Arkansas: Degray Reservoir And The Upper Cadda River, Robert T. Allen Oct 1982

A Faunal And Seasonal Study Of The Aquatic Insects In Two Water Ecosystems In South Arkansas: Degray Reservoir And The Upper Cadda River, Robert T. Allen

Arkansas Water Resources Center Technical Reports

The impounding of the lower Caddo River to create DeGray Reservoir radically changed the water habitats in that portion of the Caddo River. A number of new and different habitats were created by the lake. The objective of this study was to determine what, if any, differences existed between the aquatic insect biotas of DeGray Reservoir and the upper Caddo River. Four collecting stations along the shore of DeGray Reservoir and four stations along the upper Caddo River were selected as sampling sites. Collections were made at one month (March, April, Oct., Nov.) intervals or at two week intervals (May, …


The Effects Of Varying Fresh Water Discharge On Dispersion In An Estuarine Hydraulic Model Of The Lafayette River, Norfolk, Virginia, Michael J. Jugan Oct 1982

The Effects Of Varying Fresh Water Discharge On Dispersion In An Estuarine Hydraulic Model Of The Lafayette River, Norfolk, Virginia, Michael J. Jugan

OES Theses and Dissertations

Three experimental tests were conducted in the Lafayette River branch of the Chesapeake Bay Hydraulic Model, each successive test with an increase in the amount of fresh water discharged into the head of the river. This was done to study the response from varying river discharge on mixing parameters including the longitudinal dispersion coefficient (E).

The model generated a tide of constant range and period. Batch releases of Rhodamine WT dye were made in the model and sampled throughout the river for ten tidal cycles. Samples were taken simultaneously at selected high and low water slack.

The calculation of the …


Factors Effecting Phytoplankton Assemblages In The Lafayette River Estuary, Laurie Ann Kalenak Oct 1982

Factors Effecting Phytoplankton Assemblages In The Lafayette River Estuary, Laurie Ann Kalenak

OES Theses and Dissertations

Chemical and physical parameters were measured with phytoplankton species composition and abundance in the Lafayette River from August to October 1981. Stations located in four distinct areas of the river were statistically analyzed to determine data relationships. Environmental factors considered as potentially influencing the presence and numbers of phytoplankton were salinity, temperature, Secchi depth, tidal phase, orthophosphate, combined nitrates and nitrites, ammonia, and reactive silicates.

The River mouth had higher salinity and nutrient values, with lower temperatures than the other river sections. Diatoms were the dominant cells in this section of the River. At mid-river, salinity and nutrient concentrations decreased, …


Effects Of Water On The Fate Of Herbicides In Irrigated Soils, Terry L. Lavy Aug 1982

Effects Of Water On The Fate Of Herbicides In Irrigated Soils, Terry L. Lavy

Arkansas Water Resources Center Technical Reports

The wide use of soil-applied herbicides necessitates an understanding of their fate in soil if we are to use them in the most beneficial manner. All herbicides have some degree of water solubility and the field performance of many are dependent on ample, timely availability of soil moisture. It is important that different aspects of soil-herbicide-water interactions be thoroughly investigated. An excess use of water for irrigation purposes can result in the downward movement of herbicides in the soil profile. Subsoils are less adsorptive and a decreased degradation potential exists when herbicides move below the top 15 cm. In sandy …


Atrazine Degradation, Sorption And Bioconcentration In Water Systems, Duane C. Wolf, Ramon L. Jackson Aug 1982

Atrazine Degradation, Sorption And Bioconcentration In Water Systems, Duane C. Wolf, Ramon L. Jackson

Arkansas Water Resources Center Technical Reports

The herbicide atrazine is used extensively to control broadleaf and grass weeds in such crops as sorghum and corn. A small portion of the atrazine may be lost from the area of application by surface runoff and could enter a stream or lake. The objective of this study was to evaluate atrazine degradation, sorption, and bioconcentration in watersediment systems. The results indicated that sediments with lower pH values and higher organic matter levels adsorbed higher levels of atrazine than sediments with neutral pH values and lower organic matter levels. Microbial decomposition of the herbicide was slow under the conditions of …


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 …


Development, Verification And Use Of Methods To Model Chemical And Thermal Processes For Lakes Mead And Powell, John Eric Edinger, Edward M. Buchak, Joseph S. Norton, Bureau Of Reclamation Jun 1982

Development, Verification And Use Of Methods To Model Chemical And Thermal Processes For Lakes Mead And Powell, John Eric Edinger, Edward M. Buchak, Joseph S. Norton, Bureau Of Reclamation

Publications (WR)

Analysis and development of carbonate-bicarbonate chemical subroutine.


Foliar Diseases Of Wheat., A. G.P. Brown Jan 1982

Foliar Diseases Of Wheat., A. G.P. Brown

Experimental Summaries - Plant Research

Leaf diseases in the wheatbelt. Fungicides to control Septoria nodorum. Fungicide rate. Fungicides on yellow spot. Effect of stubble residues on septoria. Septoria: economic control on farm crops. 82Ba38 82BA37


Plant Viruses., G. D. Mclean, L. K. Price, J. A. Weir, J. M. Allen, P. Fievez, P. A. Portmann, R. J. Mclean, J. D. Sandow Jan 1982

Plant Viruses., G. D. Mclean, L. K. Price, J. A. Weir, J. M. Allen, P. Fievez, P. A. Portmann, R. J. Mclean, J. D. Sandow

Experimental Summaries - Plant Research

Clover viruses, 82ES38, 82AL47, 82MA19, 82BR19, 82BY29; 82BU5, 82HA9. Lupin virus, diseases. Barley yellow dwarf virus, 82AL46, 82AL51, 82B10, 82BA33, 82BR16, 82BR18, 82C29, 82E27, 82ES37, 82ES40, 82JE19, 82JE20, 82KA33, 82KA34, 82ABI3, 82MA18, 82MN22, 82MT34, 82NA32, 82WH28,82B8, 82MN17, 82E24, 82MT30, 82E25, 82MN18, 82MT31, 82B9, 82ABI2, 82BA31, 82C26, 82JE17, 82WH27, 82AL45, 82BR17, 82ES39, 82MA1, 82MA117, 82MT33,


Investigations Of Ryegrass Toxicity., Brian A. Stynes. Jan 1982

Investigations Of Ryegrass Toxicity., Brian A. Stynes.

Experimental Summaries - Plant Research

Control of spray topping, 82KA28. Emergence of nematode larvae from galls, 82KA29, 82NA33, 82M019. Effects of long term cropping, 81KA57. Long term effects of spray topping, 81KA58. Development of toxicity, 81KA47, 81NA47, 81M047.


Report No 56 - 1981 Review Of Rainfall And Wetlands In The South-West Of Western Australia, J. A.K. Lane, D. R. Munro Jan 1982

Report No 56 - 1981 Review Of Rainfall And Wetlands In The South-West Of Western Australia, J. A.K. Lane, D. R. Munro

Fisheries Research Reports

An account is given of the biological principles involved in decisions concerning duck-shooting seasons in the south-west of Western Australia.

The conditions for waterfowl which prevailed during 1981 are described through the use of rainfall statistics and data obtained from the Department's wetland monitoring programme.

Rainfall was generally average over central and northern areas of the south-west during 1981. Rainfall in southern areas, however, was generally

below to much-below-average, although south coastal areas from Augusta to Albany received average falls.

Unusually heavy falls were recorded in North Coastal, North Central and Central Coastal Districts in May, and average falls were …


Sorrel, Dicamba Soil Residual Effects, Glean, Veldt Grass, Declared Weeds Blackberry, Pattersons Curse, Penny Royal, J Moore Jan 1982

Sorrel, Dicamba Soil Residual Effects, Glean, Veldt Grass, Declared Weeds Blackberry, Pattersons Curse, Penny Royal, J Moore

Experimental Summaries - Plant Research

CONCLUSIONS This trial has confirmed the field observation that 2,4,5-T whilst giving good initial control of Pennyroyal, fails after a number of years. Round up has a far longer term effect. This can only be attributed to a more complete initial kill as both herbicides are essentially non residual. Further work needs to be conducted on Round up in combination with soil residual chemicals or multiple applications to overcome the problem of reinfestation from seed reserves. 81A1 -01


Grapevines - Herbicide Tolerance, Sorrel - Effects Of Nutrients, Bracken - Wick Application, Pennyroyal - Control, Blackberry – Control., John Moore Jan 1982

Grapevines - Herbicide Tolerance, Sorrel - Effects Of Nutrients, Bracken - Wick Application, Pennyroyal - Control, Blackberry – Control., John Moore

Experimental Summaries - Plant Research

Grapevines - Herbicide tolerance Sorrel -Effects of Nutrients Bracken- Wick application Pennyroyal - Control Blackberry - Control 82 MT 57, 82 MT 58, 82 MT 59, 81 MT 60, 80 KA 40, 80KA39, 82 AL 48, 80 AL 10, 81 AL 101,


Oilseed Agronomy., A. G. Mckay Jan 1982

Oilseed Agronomy., A. G. Mckay

Experimental Summaries - Plant Research

Time of nitrogen application on rapeseed, 82MT39. Time of sowing x rate of nitrogen on rapeseed, 82MA16, 82AL42. Oilseed phenology trials brassica species, 82A5, 82BA40, 82C35, 82E30, 82M33, 82MT36, 82WH29. Rapeseed windrowing, time of harvest, 82MT35, 82AL50. Shattering differences among rapeseed lines, 82MT37, 82WH30. Wesroona reselection evaluation, 82MT38. Triazine herbicide resistant rapeseed, 82GL12. Podquat on rape seed 82MT54. Sunflower varieties, winter sown, 82GE31


1. Phosphorus Sources Trials 2. Miscellaneous Trials, J W. Bowden, R J. Lunt, M J. Baker Jan 1982

1. Phosphorus Sources Trials 2. Miscellaneous Trials, J W. Bowden, R J. Lunt, M J. Baker

Experimental Summaries - Plant Research

Sources of phosphorus trials - 1982 results. Pasture Trials, 76MT10, 77MT1, 77MT2, 76BU1, 77EI. Cropping Trials, 76WH14, 76WH10, 76WH9, 76N4, 76LG6, 80BA6. Trials not assessed in 1982, 77WH2 Pasture phase. Miscellaneous trials. Long term trials, 66M30, 65Al, 65A1, 65C5, 69WH15, 75LG26, 81N044, 78BA7. 1982 Trials, 82N04, 82BA2, 82N02, 82N05, 82WH2, 81N044.


Soil Physical Conditions And Crop Production, A. P. Hamlin Jan 1982

Soil Physical Conditions And Crop Production, A. P. Hamlin

Experimental Summaries - Plant Research

1a. Differences in water balance and resultant crop growth related to soil structure: Merredin red brown solonized earth. 1b. Soil structure effects on crop growth (Merredin). 77M13, 77M56. 2. Water balance studies under wheat on Wongan loamy sand (82WH8)


Summary Of Experimental Results., J. Peirce, B. J. Rayner Jan 1982

Summary Of Experimental Results., J. Peirce, B. J. Rayner

Experimental Summaries - Plant Research

81GE22. 81GE28, soursob control. 81N056, in cereals. 81N057. 82LG34, chemical x water volumes (broadleaved weeds). 82LG36, hoegrass, rate x volume (ryegrass). 82N039, crop damage in wheel tracks x spraying. 82N043, ropewick for cape tulip control. 82NR3, patersons curse control in hay crops. 82NR8, patersons curse control in hay crops. 82N055, hoegrass, rate x volume (wild oats). 82N056, chemical x volume (broadleaved weeds). Demonstration, soursob control in cereals. 82ME44, matricaria control in cereals. 82ME57, crop damage in wheel tracks x spraying. 82ME59, chemical x volume (broadleaved weeds). 82ME60, hoegrass, rate x volume (ryegrass). 82ME81, matricaria control in pastures. 82ME86, cereal tolerance …


Phosphorus Nutrition On Leaching Sands., D. M. Deeley, S. M. Mason, B. G. Barker Jan 1982

Phosphorus Nutrition On Leaching Sands., D. M. Deeley, S. M. Mason, B. G. Barker

Experimental Summaries - Plant Research

The excessive amounts of nutrients entering the Peel-Harvey Estuarine system have resulted in a marked increase in the abundance of algal species .within the estuary and reduced production on the sandy coastal soils of the catchment from which the nutrients are being leached. Recent stream samplings by D.C.E have shown that the deep grey Bassendean sands may be contributing up to 40 per cent of the total P loading in the Harvey River. Agriculture Department trials around Albany on similar sands have shown that up to 80 per cent of the bicarb extractable P may be lost after only 150 …


Low Rainfall Pasture Project., M. Ewing Jan 1982

Low Rainfall Pasture Project., M. Ewing

Experimental Summaries - Plant Research

1. Variety Trials - large plots: 82ME47, 82ME48, 82ME49, 82ME50, 82ME51, 82M27, 82N044, 82N31, 82TS27, 82LG32, 82TS32 2. Variety Tests – rows: 82M40, 82M44, 82M45, 82M49, 82M59, 82ME77. 3. Pasture Establishment and Re-establishment: 82M41, 82M42. 4. Lupins - Rates of P. 82ME64.


Alternative Pasture Species To Ryegrass For Areas Affected By Annual Ryegrass Toxicity., P. Dixon Jan 1982

Alternative Pasture Species To Ryegrass For Areas Affected By Annual Ryegrass Toxicity., P. Dixon

Experimental Summaries - Plant Research

The aim of this project is to find alternative pasture species to ryegrass in areas which are affected by Annual Ryegrass Toxicity, 82 KA 45. Pasture species row evaluation, 82 KA 40. Pasture species row evaluation, 82 KA 41. Pasture species row evaluation, 82 KA 42. Pasture species row evaluation, 82 KA 43. Medic species trial, 82 KA 44. Medic species trial, 82 KA 45.


Diseases Of Lupins And Lupinosis., P M. Wood Jan 1982

Diseases Of Lupins And Lupinosis., P M. Wood

Experimental Summaries - Plant Research

Lupin diseases, 82 TS 30, 82 TS 29, 82 TS 28, 82 GE 24, 82 ME 45, 82 ME 46, 82 BR 20,


Pasture Species Investigations High Rainfall Area., D. A. Nicholas Jan 1982

Pasture Species Investigations High Rainfall Area., D. A. Nicholas

Experimental Summaries - Plant Research

Selection of an alternative to cv Woogenellup clover. 79MT48, Mount Barker research station. 79MA13, Palgarup. 80AL59, Narribup. 80BR18, Mayanup. 80BU7, Vasse. 81NA37, North Bannister. 81PE6, Byford. 82NA36, West Wandering. 82AL72, South Stirlings. Screening of midseason to late maturing lines of subterranean clover. 82BU12, Karridale. 82AL71, Cuthbert.


Long Term Rotation Trials, Lupins, Wheat Rotation, Continuous Cropping With Nitrogenous Fertiliser, I. Rowland Jan 1982

Long Term Rotation Trials, Lupins, Wheat Rotation, Continuous Cropping With Nitrogenous Fertiliser, I. Rowland

Experimental Summaries - Plant Research

Long Term Rotation Trials, 66M29, 67C13, 67N4, 68E5, 68SG5, 73SG16. Lupins, wheat rotation, 79GE36, 80TS3, 82TS2. Continuous cropping with nitrogenous fertiliser, 80NA6.