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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Chemical and Biological Problems in the Grand Canyon

05 May 1973 (has links)
A survey of chemical and bacteriological water quality in the Grand Canyon was undertaken to assess possible health hazards to river travelers. The water quality of the main Colorado River channel is relatively stable with only slight increases in ionic concentration and bacteriological load with respect to distance from Lee Ferry and time over the summer season. The tributary streams show extreme temporal variability in chemical water quality and bacteriological contamination as a result of the summer rain and flood patterns in the tributary canyons. These side streams pose a definite health hazard to unwary river travelers. More extensive sampling is called for to determine the sources of this contamination and to protect the quality of the Grand Canyon experience.
12

Nitrogen Removal from Secondary Effluent Applied to a Soil-Turf Filter

Anderson, E. L., Pepper, I. L., Johnson, G. V. 15 April 1978 (has links)
From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / This study investigated the potential of a soil-turf filter to renovate secondary effluent applied in excess of consumptive use. Lysimeter plots were filled with a sand and a sand mix, and seeded to winter ryegrass. In spring, plots were scalped and seeded to bermudagrass. Plots were drip irrigated twice a week with secondary effluent at rates of 10, 17, 22, 34, and 43 mm/day. Leachate and effluent were analyzed for NH -N, NO,-N, and organic-N. Grass clippings were oven dried, weighed, and analyzed for organic -N. Percent of leachate available for groundwater recharge was 50% at the lowest rate and 68% at the highest rate when values were averaged for both soils. The amount of nitrogen removed by the soil-turf filter using sand was 42 to 87% and 52 to 90% on the mix, decreasing as application rate increased. The highest nitrogen removal and utilization occurred at the lowest application rate. Turf utilization of nitrogen was 10 to 28% on sand and 18 to 36% on mix, decreasing as rate of application increased. The sand-turf filter renovated 22 mm/day and the mix-turf filter renovated 43 mm/day, yielding leachate averaging less than 10 ppm NO₃-N.
13

Reclamation of Orphaned Mine Sites and Their Effect on the Water Quality of the Lynx Creek Watershed

Verma, Tika R., Felix, Ernesto N. 16 April 1977 (has links)
From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Lynx Creek Watershed is located eight miles southeast of Prescott, Arizona, on the Prescott National Forest. The watershed consists of 13,600 acres, which are National Forest Lands. Approximately 600 acres in the watershed are patented mining claims. Gold was discovered in Lynx Creek in 1863 and the watershed was extensively mined for gold, silver and copper. The aftermath of the mining has resulted in numerous mine shafts, waste dumps and mill tailing ponds that were abandoned after the ore was played out. Drainage from the orphaned mine sites contribute a certain extent of toxic mineral and sediment pollution into Lynx Creek and eventually into Lynx Lake. Lynx Creek carries runoff which is slightly acidic in nature and has high concentrations of copper, manganese, iron, zinc and sulfates. The mineral pollutants have reduced the recreational and fisheries potential of the Lake. The Sheldon Mine complex consisting of a waste dump and the mill tailing dump were considered the major sources of pollutants into the Lake. The Sheldon Tailings pond was rehabilitated during the summer of 1975 and the waste dump during the summer of 1976 as part of a reclamation study that is being sponsored by SEAM (Surface Environment and Mining). The study is being conducted cooperatively by the School of Renewable Natural Resources, University of Arizona, and the Prescott National Forest. Both sites were culturally treated and dressed with lime and topsoil. Studies are currently being conducted to measure the beneficial effects of the reclamation projects.
14

Bottom Sediment Analysis of the Recreational Waters of Upper Sabino Creek

McKee, Patrick L., Brickler, Stanley K. 16 April 1977 (has links)
From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Bottom sediment quality of the upper four miles of Sabino Creek in the Santa Catalina mountains near Tucson, Arizona was examined from September, 1975 through August, 1976. Two primary bottom sediment parameters were examined: 1) sediment fecal bacterial concentrations, and 2) sediment particle size distribution. Analyses of bottom sediment parameters and selected surface water parameters were conducted to ascertain interrelationships between bottom sediment quality and surface water quality. Results indicate the importance of bottom sediments in the overall quality of the Creek. Bottom sediment fecal bacterial concentrations have a significant influence on surface water fecal bacterial concentrations through suspension of sediment stored bacteria into the overlying water. Significantly higher bacterial concentrations were observed during highest recreational use periods.
15

Ephemeral Flow and Water Quality Problems: A Case Study of the San Pedro River in Southeastern Arizona

Keith, S. J. 15 April 1978 (has links)
From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Discontinuous water quality data for the San Pedro River in southeastern Arizona is analyzed to illustrate the nature of water quality problems of ephemeral flow. The San Pedro drains a northerly-trending basin of 4,483 square miles, of which 696 are in Mexico and 3,787 in Arizona. Several questions arise in the consideration of a rational management plan: what is the necessity for protection of ephemeral flow quality when the channel consists of a dry wash much of the year, where there is little aquatic or wildlife to protect, and where occasional flow during flood conditions is put to little use by humans; and where and how do we use the ephemeral flow it is indeed decided to utilize it. Such questions as these form the basis of this discussion in an effort to bring out the point that water quality problems of ephemeral flow in arid areas differ from those in the humid zone. It is argued that in between the extremes of prohibiting or treating all runoff or eliminating all sources of pollution, there is actually little that can be done to control all sources of pollution in this typical arid stream, despite the fact that standards, for the most part unattainable, have been set for this flow.
16

Vývoj znečištění ovzduší ve vybraném území / Development of air pollution in the selected area

BARTŮŠEK, Ondřej January 2017 (has links)
This thesis presents a comparison of the development of the concentrations of nitrogen oxides and sulfur dioxide in the air in the Usti region. The work described generally air pollution and related terms such as the sources of pollution emission, immission and atmospheric deposition. The study also evaluated pollution nitrogen oxides and sutur dioxide in the Usti region. This work describes the methods that were used in the calculations and evaluations. It also deals with the selecting appropriate measuring stations to handle the development of the concentrations of these substances in the air. The aim of this work is to find trends in time series of concentrations of NOx and SO2 and statistical evaluation of development levels in selected cities Ústí Region. The next section is evaluated spatial analysis of the concentration of nitrogen oxides and sulfur dioxide in the air in the Ústí Region. This area was chosen primarily because it is characterized by significant air pollution.
17

Análises espaço temporais da qualidade da água bruta do Aquífero Bauru na área urbana de Araguari, MG

Borges, Eduardo Humberto Campos 21 March 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / O Aquífero Bauru é considerado a unidade hidrogeológica mais importante de Araguari, Minas Gerais. A água deste aquífero é intensamente explorada devido ao baixo custo de captação, que está relacionado ao fato de ser um aquífero freático, pouco profundo e local, submetido a uma abundante recarga. No entanto, essas características o torna potencialmente vulnerável aos agentes poluidores. Este trabalho teve como objetivo oferecer um panorama geral sobre a qualidade da água bruta do aquífero Bauru, na zona urbana de Araguari, identificando possíveis fontes de poluição. As amostras de água foram coletadas em poços da concessionária de abastecimento público. Os critérios para seleção dos poços foram: distribuição espacial, operacionalidade, estrutura e zonas de risco. As amostras foram coletadas a montante do ponto de aplicação do desinfetante, garantindo os aspectos qualitativos da água bruta. Foram amostrados 68 poços, correspondendo a 80 % do poços em operação. Foram realizadas 2 campanhas de campo, sendo a primeira em novembro de 2012 e a segunda em dezembro de 2014. A amostras foram submetidas a ensaios de pH, nitrato, nitrito, fósforo, DQO, DBO5, cor aparente, turbidez, sólidos totais, sólidos dissolvidos totais, sólidos suspensos totais, sólidos voláteis totais e fixos totais. Os resultados das etapas de campo e laboratoriais permitiram o mapeamento dos parâmetros de qualidade e a identificação das áreas críticas em termos de poluição. Os resultados indicaram que vazamentos de esgoto sanitário, em áreas que apresentam elevados índices de vulnerabilidade, podem ser a causa da presença nitrato e sólidos voláteis em alguns poços analisados. Apesar disso, a água bruta do Aquífero Bauru ainda apresenta boa qualidade com propriedades físico- químicas e bacteriológicas adequadas a diversos usos. Apesar das concentrações encontradas ainda serem inferiores aos limites estabelecidos pela legislação vigente, fica evidente a importância do monitoramento contínuo da qualidade da água subterrânea extraída para o abastecimento urbano. / The Bauru Aquifer is considered the most important hydrogeological unit of the city of Araguari, Minas Gerais. The water from this aquifer is exploited due to low cost, which is related to the fact of being a shallow and local subjected to an abundant recharging. However, these characteristics makes it potentially vulnerable to pollutants. This work aimed to provide an overview of the quality of raw water from the aquifer Bauru underlying the urban area of Araguari, identifying possible sources of pollution. Water samples were collected in wells of public water utility. The criteria for selection of the wells were: spatial distribution, operation, structure and risk areas. The samples were collected upstream of disinfectant application point, ensuring the qualitative aspects of raw water. 68 wells were sampled corresponding to 80% of the wells in operation. Were held two field campaigns, the first in November 2012 and the second in December 2014. The samples were subjected to pH tests, nitrate, nitrite, phosphorus, COD, BOD, apparent color, turbidity, total solids, solids total dissolved, total suspended solids, total volatile solids and total fixed. The results of field and laboratory steps allowed the mapping of quality parameters and the identification of critical areas in terms of pollution. The results indicated that wastewater leaks in areas that have high levels of vulnerability may be the cause of nitrate and volatile solids present in some wells examined. Nevertheless, the raw water from the aquifer Bauru still has good quality with physical-chemical and bacteriological appropriate to different uses. Although the concentrations found are still below the limits established by law, it is clear the importance of continuous monitoring of groundwater quality extracted for urban supply. / Dissertação (Mestrado)
18

Nutrient and Water Quality Analysis of a Lake Erie Headwater Tributary

Hejna, MaryAnne 25 August 2020 (has links)
No description available.
19

The Use of Chemical Hydrographs in Groundwater Quality Studies

Schmidt, Kenneth D. 23 April 1971 (has links)
From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / High nitrates in drinking water are significant in relation to an infant disease, methemoglobinemia, and the U.S. public health service has set a limit of 45 ppm for human consumption. This paper illustrates how chemical hydrographs were used in a study of nitrates in the groundwater of the Fresno-Clovis metropolitan area (F.C.M.A.) of semiarid central California. The area comprises about 145 square miles, with a population of 310,000. Urban water use is entirely derived from wells, whereas the surrounding agriculture relies on surface and ground water. In 1965, the California department of water resources noted nitrate concentrations in the F.C.M.A. were exceeding the safe limit. A number of sources of error in chemical analyses of water quality are noted. A measure of the accuracies of analyses and a method of double-checking anomalous results is furnished by plotting chemical hydrographs of individual wells. Seasonal changes in nitrate were consistent for many parts of the area, and were related to hydrogeologic factors and parameters directly affecting nitrification. Nitrate hydrographs were monitored by chloride hydrographs. The highest nitrate concentrations were in the shallower parts of the aquifer, and well deepening and changes in water level, pumping patterns and recharge rates complicated interpretations. However, the hydrographs helped to pinpoint the source of nitrate in areas where several possible sources were present.
20

Salinity Problems of the Safford Valley: An Interdisciplinary Analysis

Muller, Anthony B. 05 May 1973 (has links)
From the Proceedings of the 1973 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 4-5, 1973, Tucson, Arizona / A change in groundwater quality, averaging approximately +0.13 millimhos electrical conductivity and +35 ppm chloride per year, has been documented between 1940 and 1972 with data from ten long -term sample wells. The decrement in the water quality of the surficial aquifer seems to be attributable to four major mechanisms. An increase in salinity may be expected from leakage of saline water from the artesian aquifer. Such leakage would be stimulated by pumping- caused reduction of confining pressure, and by the puncture of the cap beds by deep wells. Water reaching the aquifer from natural recharge may contribute salts to the system. Such recharging water, if passed through soluble beds, could contribute to the salt. Lateral movement of water through similar deposits may be a contribution, and the concentration and infiltration of agricultural water could also add to aquifer salinity. The economic analysis of the Safford Valley, based on the modeling of a "Representative Farm" analog, indicates that cotton will remain economical to produce on the basis of the projected salinity trends, for a significant time beyond limits of prediction. The analysis indicates that the optimum salt-resistant crops for the area are being cultivated, and, of these, alfalfa will cease to be productive in large areas of the valley by 1990. The entire valley will not produce alfalfa for profit by 2040. The methodologies shown in the paper indicate how pumping influences salinity change and outline salinity control recommendations for the area.

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